GAINESVILLE, Fla. — Vividly colorful giant clams officially called tridacnids decorate many an upscale aquarium. But now experts say they boast an exterior beauty that masks an ugly truth: their potential for carrying foreign diseases.

In findings that may impact the reef clam industry as well as international trade, a University of Florida veterinary pathologist recently discovered Perkinsus olseni, an internationally reportable foreign pathogen, in aquacultured clams imported from Vietnam.

While not believed to be a threat to human health or other reef aquarium species, the pathogen’s presence concerns scientists as well as aquaculture industry representatives and points out the largely unregulated environment in which the importation of aquacultured reef clams from Asia occurs.

“I had 30 clams in my lab as part of a student research project,” said Barbara Sheppard, a clinical associate professor of pathology at the UF College of Veterinary Medicine. “Then they started looking sickly, and within four months, all of them were dead.”

As a pathologist, Sheppard was intrigued. She began investigating the cause of death by freezing tissues, putting them into formalin and conducting histopathology and DNA tests in her laboratory. Her findings, which will appear in an upcoming issue of Diseases of Aquatic Organisms, showed the presence of Perkinsus olseni along with a new species of Perkinsus that has yet to be characterized.

“This is an important finding,” said Ralph Elston, president of AquaTechnics, a Carlsborg, Wash.-based company that provides veterinary, laboratory and environmental assessment services to the shellfish industry. “It indicates the potential risk of the spread of animal disease when health monitoring is not in place to control such risks.”

Elston added that further research is needed to evaluate the distribution of previously unknown species of Perkinsus in Florida.

Giant clams are the largest bivalves in the world. Their range stretches across the Indo-Pacific region from the eastern coast of Africa in the west to the South Pacific in the east, according to the United Nations Environment Program’s World Conservation Monitoring Center. These clams represent an increasingly large proportion of the live invertebrates imported to become aquarium specimens. As a result of overexploitation, all species of giant clams are included in the Convention on International Trade in Endangered Species of Wild Fauna and Flora, an international agreement between governments that aims to ensure that international trade in specimens of wild animals and plants does not threaten their survival.

Based on CITES data from 1993-2001, Vietnam has dominated the export of live giant clams since 1998. The United States and Europe are the main importers, and captive bred, or aquacultured, clams represent only about a third of the nearly 1 million tridacnids traded worldwide.

Sheppard is now collaborating with the Virginia Institute of Marine Sciences, the Maryland Department of Agriculture and Anita Wright, a Perkinsus researcher and associate professor at UF, to further characterize the new exotic species of Perkinsus that Sheppard discovered in her clam colony.

“This is not a zoonotic disease, transmissible to people,” Sheppard said. “No one is going to get sick from this, as far as we know. The problem here is economic and international trade. We know that Perkinsus is a pathogen of aquatic shellfish, and the reason it is so important is that it makes animals very vulnerable to dying when the weather gets hot or when they get stressed in some other way.”

She added that a major pathogen known as Perkinsus marinus is already associated with the depletion of major oyster stocks on the Atlantic coast.

“It’s indigenous; you can’t avoid it, and we know that particular pathogen is already economically devastating to our shellfish industries,” Sheppard said. “They don’t want this Pacific version of Perkinsus (olseni) to be transported here.”

Although the infected clams were found in Florida, tridacnids are imported and distributed to hobbyists throughout the United States. Sheppard’s findings suggest that almost certainly clams infected with Perkinsus olseni and the new Perkinsus species have made their way into consumer aquariums throughout the United States, she said.

“This is a great example of why you should never release an aquarium animal anywhere, under any circumstances,” said Ruth Francis-Floyd, director of UF’s Aquatic Animal Health Program. Aquarium owners seeking an aquatic veterinarian may reference the AquaVets Web site at www.aquavetmed.info/.

The ornamental aquarium trade operates globally with very few restrictions to transport product as quickly as possible, said Craig Watson, director of UF’s Tropical Aquaculture Laboratory in Ruskin.

“There are probably 3,000 species involved, and no one species has the value to justify the cost of a quarantine facility big enough to handle everything,” Watson said.

Members of the clam aquaculture industry as well as the oyster industry are aware of the recent Perkinsus olseni findings and are trying to respond, he added.

Watson said he is working with Florida aquaculture representatives who “really want to do the right thing” and added that his laboratory has proposed a voluntary protocol involving testing and quarantine procedures.

“The cost of doing this, however, is significant,” he said. “The ultimate goal would be to start a Perkinsus-free aquaculture industry in the United States where baby clams that have never been exposed to the disease are produced.”

Researchers at UF’s College of Veterinary Medicine’s Analytical Toxicology Core Laboratory, in collaboration with Mote Marine Laboratory in Sarasota, are studying the bull shark’s exposure to pharmaceutical drug residue found in the waters of the Caloosahatchee River near Fort Myers. Bull sharks leave the ocean to spend time in brackish rivers and estuaries, and the river serves as a nursery for their young.

“Because bull sharks have the unique ability to survive in both saltwater and freshwater environments, they are in close, frequent contact with people — and, as a result, are frequently exposed to wastewater pollutants found in freshwater basins,” said Jim Gelsleichter, senior scientist at Mote Marine Laboratory.

Scientists are trying to determine whether exposure to prescription residue contaminants from water treatment plants and other sources affects the sharks’ ability to grow and reproduce.

“Treatment plants were designed to remove pathogens like viruses and bacterial agents, and that they do very well,” said Nancy Szabo, Gelsleichter’s co-investigator and director of UF’s Analytical Toxicology Core Laboratory. But these facilities simply aren’t designed to deal with pharmaceuticals, she said.

Evidence suggests that low-level pharmaceutical pollution is widespread. In 1999 and 2000, the U.S. Geological Survey sampled 139 streams in 30 states for organic wastewater contaminants, including common pharmaceuticals. Eighty percent of the streams studied contained traces of chemical pollution. The consequences of such contamination are not yet fully known, although some research has shown even low levels of these contaminants affect several fish species.

Federal guidelines for proper disposal of prescription drugs recommend flushing them down the toilet only if the accompanying patient information specifically says it is safe to do so.

Gelsleichter is testing for the presence and levels of human drug contaminants in bull shark blood by tagging bull sharks in the river basin with passive sampling devices — silicone rubber discs that collect chemical samples in the water for later examination. When sharks are caught by local anglers or by the Mote team on subsequent research expeditions, the tags are retrieved and sent to UF’s Analytical Toxicology Core Laboratory for analysis.

When the blood and silicone-rubber discs from the bull sharks arrive at the laboratory, Szabo’s team analyzes the samples to determine the variety and concentration of chemicals present in the bull shark’s environment.

The UF laboratory specializes in non-routine analysis. Szabo’s team works with researchers both at UF and elsewhere to develop appropriate methods for measuring and analyzing whatever toxins are being examined. These techniques are tailored specifically to each client.

For the bull shark study, the UF laboratory has been able to use distinctive techniques to gauge chemical levels in bull shark blood. The laboratory worked with Mote not only to design the experiment but also to adapt the analytical methods used to ensure valid results are produced.

“The type of work we do requires a lot of effort, and one has to have the expertise available to know where to even begin,” Szabo said.

The bull shark study, which is funded through September 2008 by the Charlotte Harbor National Estuary Program and a federal grant to the National Shark Research Foundation, is the most recent collaboration between the UF laboratory and Mote. The two groups have worked together for the past nine years.

“Our collaborative efforts have provided new data on the environmental quality of essential fish habitat for the U.S. shark populations,” Gelsleichter added. “This information is necessary for NOAA (National Oceanic and Atmospheric Administration) fisheries to have so they can manage and conserve these populations from an ecosystem perspective.”

“The National Weather Service is projecting a warmer than normal winter, so horse owners should not become complacent and make sure they vaccinate their horse,” said Michael Short, equine programs manager for the Florida Department of Agriculture and Consumer Services’ Division of Animal Industry.

While state officials report no equine cases yet this year, a new single-dose vaccine recently tested in horses by a University of Florida infectious disease specialist may reduce the overall occurrence of the cyclical virus because the product can be administered any time of year, with almost immediate protection. Known as PreveNile, the vaccine began reaching veterinarians in late September.

“Horse owners who have not vaccinated their animals already should do so as soon as possible,” said Maureen Long, an associate professor of equine medicine at UF’s College of Veterinary Medicine and a nationally recognized expert on West Nile virus. “We want horse owners to vaccinate if they haven’t, because since there is no cure for West Nile Virus, prevention is really the only tool we have for controlling this ongoing threat.”

As of Oct. 31, the disease has been reported in 3,752 people nationwide and in 939 horses this year. In its most serious manifestation, West Nile virus causes fatal inflammation of the brain, and it also occurs in a variety of domestic and wild birds, including crows. Nationwide, more than 23,000 cases have been reported in horses since its initial appearance in 1999, with more than a third of these animals dying, including more than 1,000 in Florida.

West Nile virus cycles between birds and mosquitoes, and mosquito bites are the only way a horse can become infected. Horses and humans infected with the disease cannot infect other horses and humans, experts say. Compared with most states, Florida has a year-round mosquito season, but the insects are most active in the summer and fall.

“Vaccination is a very important component of horses’ health, and the arboviruses, West Nile virus and Eastern equine encephalitis, are two diseases we strongly urge horse owners to have their horses vaccinated for,” Short said. “Many horses die every year from these two diseases and those we report are just confirmed cases. There probably are a lot more out there that we don’t hear about.”

PreveNile is marketed by Intervet Inc. and received approval from the U.S. Department of Agriculture for commercial use in July. Long and her staff provided immune protection studies for the product, the first live-virus vaccine to prevent West Nile virus in horses.

PreveNile provides 12 months of immunity and may be used even if other products have been administered within the past year. Other vaccines previously on the market required two doses before becoming effective.

“The other vaccines are labeled only for protection against viremia, or the presence of virus in the blood,” Long said. “This is the only market vaccine that is labeled for protection against disease itself because of the way in which we tested the product in horses.”

Some 19,000 humans have been infected with the virus, and nearly 800 people have died from it, according to the USDA’s animal and plant health industry surveillance program.

“There is intense interest in developing vaccination strategies for humans,” Long said. “A similar product is currently being tested in humans by Acambis Inc., the human vaccine company that constructed this product originally. Work in horses is invaluable for assessment of this type of vaccine for use in humans.”

Horse owners with questions about vaccination protocols and options should contact their veterinarian.

Manatees depend on both natural and artificial warm water refuges like those found near coal-burning power plants to survive cold winters. As older coal-burning power plants are phased out in the next 10 to 20 years, researchers fear chronic exposure to cooler waters could weaken the large herbivores’ immune system, and they could sicken or even die.

By sampling manatees’ tear film in addition to performing other standard tests, scientists think they might be able to more efficiently evaluate manatees’ immune system function and better determine strategies for rescue, treatment and rehabilitation.

The current tear analysis project, believed to be the first of its kind, builds on work UF veterinary scientists published recently in the journal Veterinary Ophthalmology that described the abundance of blood vessels found in manatee corneas. Blood vessels could have a tendency to move into the cornea to supply oxygen because the tear film creates a barrier so thick that oxygen present in air can’t penetrate it, said Don Samuelson, a professor of ophthalmology in the Marine Mammal Medicine program at UF’s College of Veterinary Medicine.

Manatees are believed to have the thickest tear film of any sea mammal, and possibly of any animal, Samuelson said. In general, mammals produce tears to protect against infection, because the eye itself does not have immune system components.

“Through this protection against the potential for infection, the manatee is able to enter murky waters just rich with potential pathogens,” Samuelson said. “For that reason, we think this very thick tear film, undoubtedly rich with antimicrobial components, serves to protect in areas that could otherwise be devastating.”

Researchers speculate that tears, which can be collected without removing manatees from the water using a small, soft cotton swab, may one day be used along with or instead of blood tests to assess health status and to gauge whether the mammals were recently exposed to health threats such as red tide. Ongoing UF studies are exploring the relationship between the tear film and blood vessel formation.

“One of the findings of our earlier work was that there is absolutely no pathology involved in the formation of these manatee blood vessels, which in other species occur predominantly because of trauma or disease,” Samuelson said. “So the question is, why do these mammals have such thick tears that corneal blood vessels form naturally, even in the fetus?”

Samuelson collaborated with Roger Reep, a UF professor of neurology, and Jenny Harper, a recent doctoral graduate who is now an assistant professor at Coastal Georgia Community College. Together they examined 26 eyes from 22 individual manatees and constructed 3-D images of the corneas.

“We’ve completed the evaluation and mapped the blood vessels, so we know where within the cornea they are located and how many there are,” Samuelson said. “Our next goal is to start examining the tears and evaluate them with regard to the whole animal’s health status.”

He added that the recent study clearly documented the fact that these blood vessels are present, do not appear to interfere with manatee vision and appear to be a part of manatee anatomy beginning in the embryo.

“With that in mind, we are examining the tears to see what they exactly consist of, particularly with regard to the anti-infectious component,” Samuelson said. “This may eventually be an opportunity to examine an individual manatee’s state of health with regard to their immune system by analyzing their tears.”

Tear analysis is being used in human ophthalmology and is in its early stages in veterinary medicine, he said.

Kendal Harr, assistant director of UF’s Marine Mammal Medicine program, is collaborating with Samuelson on a large federal Fish and Wildlife Service research initiative to assess the immune function of manatees at Homosassa Springs State Park. She is coordinating sample and data collection for the UF veterinary college as part of the project.

“We suspect that manatees’ thick, mucusy tear film likely contains proteins, such as antibodies, that would prevent bacteria and other pathogens from causing disease,” Harr said. “We are currently developing qualitative assays to measure antibodies in blood as well as in tear film and milk.”

University of Florida researchers have discovered that despite the placid sea cows’ huge size, their bones are actually as brittle as some porcelain plates. That may make them even more vulnerable than anyone thought to suffering life-threatening injuries in a collision.

Boat strikes are the leading cause of manatee deaths in Florida, but until now scientists haven’t understood the mechanics of what happens to the endangered marine mammals when these deadly accidents occur. The surprising finding could ultimately change public policy for the management of Florida’s waterways, said Roger Reep, a professor in the UF College of Veterinary Medicine’s physiological sciences department.

“When you pick up a manatee rib, it’s much denser than a cow bone or a human bone,” Reep said. “Most people would think these ribs would be really strong, as they’re so heavy. But in fact they behave like a ceramic material. We feel this information will contribute significantly to our understanding of manatee-boat interactions, and will be critical in establishing boat speed zones adequate to minimize the chance of fatal impacts.”

Manatee bones have no marrow cavity, which is why their bones are so dense. That density makes manatee bones fragile and more likely to break than most other types, with fractures occurring more or less along straight lines as opposed to being dispersed within the bone, Reep said. The typical manatee rib weighs about 2 pounds and has a higher mineral content than other types of bone, researchers also found — up to 70 percent compared with 65 percent. While the difference seems small, it apparently translates into large changes in mechanical properties, they said.

Additional findings from the ongoing project, which mingles veterinary physiology and engineering expertise in a first-ever effort to describe the biomechanics of impact injuries, will be published in an upcoming issue of the Journal of Biomechanics. UF scientists also will discuss the study April 9 at the UF-sponsored Marine Mammal Medicine conference in Gainesville.

Using an air gun to hurl a 2-by-4-inch board toward a manatee bone target, and strain gauges to measure load at the moment of impact, the researchers are able to reconstruct the way various forces are distributed through the bone.

“You can actually measure the amount of energy that was propagated through the bone just by looking at the geometry. What we’re doing is getting an idea of the amount of energy it takes to break a bone,” said Reep, who has teamed with Jack Mecholsky, the study’s other principal investigator and a professor and associate chairman of the department of materials science and engineering at UF’s College of Engineering. They are working with UF graduate student Kari Clifton on the project, who began the study as part of her dissertation research in 1998 with funding from UF’s Marine Mammal Medicine Program.

The force applied by a boat to a manatee during impact depends primarily on boat speed, but also on variables such as the size of the boat, researchers said.

“One thing we’re not sure about yet is how much of the force of the boat actually reaches the ribs, since manatees don’t get hit directly on the ribs, but rather on the soft tissue covering the ribs,” Reep said. “This is an unanswered question.”

Manatees, listed as an endangered species by the federal government since 1967, are large, slow-swimming, gentle mammals that are entirely aquatic. Human activities are the major threat to their survival through boat-related injuries and deaths, habitat loss or degradation, and in some countries, hunting, according to the U.S. Geological Survey’s Sirenia Project.

Only about 3,000 manatees remain in the wild. Most are concentrated in Florida, but can be found in summer months as far west as Texas and as far north as Virginia. West Indian manatees can also be found in the coastal and inland waterways of Central America and on the northern coast of South America.

Officials have documented 5,329 manatee deaths in Florida from 1974 to 2004, of which 1,164 were attributed to watercraft collision, according to the Florida Fish and Wildlife Conservation Commission.

The U.S. Geological Survey’s 2003 population model predicted that if the manatee mortality rate from boating accidents continues to increase at the rate observed since 1992, the situation in the Atlantic and Southwest regions is dire, with no chance of the manatee population recovering within the next century.

“Most concerning is the fact that watercraft collisions are the leading cause of death of adult, reproductive-age manatees,” said Patti Thompson, director of science and conservation for the Maitland, Fla. based Save the Manatee Club. “Reducing adult manatee mortality is the most effective method to increasing the manatee’s recovery rate, and the reduction of watercraft-related mortality is the most productive and reliable means to reduce these deaths.”

Thompson said the UF research is significant because it could eventually lead to better boat management in the environment.

“It’s a surprising outcome of UF’s research that their bones are much more fragile than anyone expected,” Thompson said.

“This project is significant because the biochemical components of blood plasma — the liquid portion of blood — can help us determine the health status of both populations of free-ranging sea turtles and those ill sea turtles brought into rehabilitation facilities,” said Elliott Jacobson, a professor of zoological medicine at UF’s College of Veterinary Medicine and the project’s lead researcher.

Blood parameters are commonly used to assess the condition of all sorts of animals, Jacobson said, adding that more than 1,000 turtles are trapped annually in the Port St. Lucie power plant’s intake canal, making it one of the best sites in the world for access to a huge number of sea turtles. All the turtles trapped in the plant’s canal are removed, weighed, measured and tagged. Last month, scientists added a step: They take a small sample of blood from each turtle before releasing it or sending it to a rehabilitation facility.

“A reliable and sizable database consisting of what essentially are blood blueprints for turtles appearing normal, as well as for those appearing sick, could give veterinarians and rehabilitation specialists additional tools for deciding how to treat these turtles and when to return them to the wild,” Jacobson said.

Researchers aim to collect data from 415 turtles the first year and hope to continue the project for five years.

In the past century, habitat destruction, incidental and intentional turtle harvesting and temperature change have accelerated the decline of sea turtle populations worldwide, according to the Smithsonian National Zoological Park Web site. An increasing incidence of diseases and health-related problems in the wild pose an additional threat to their survival.

Today, all sea turtles found in U.S. waters are federally listed as endangered, except for the loggerhead, which is listed as threatened.

Collaborators in the project, which is funded by the Florida sea turtle license plate grant program and is a result of a grant from UF’s Opportunity Fund, include UF’s Archie Carr Center for Sea Turtle Research, Marinelife Center of Juno Beach and the Clearwater Marine Aquarium. The Archie Carr Center will create a database based on the species, size, sex and water temperature at time of sampling and will link this data to a Web page where the findings will be available to those working with sea turtles around the world.

Marinelife Center and Clearwater Marine Aquarium are the primary recipients of ill or injured turtles found in the canal. Power plant-based personnel from a federally contracted organization known as Quantum Inc. fish the turtles out of the canal. Then, Quantum staff members determine if the turtles are sick and if so, arrange for transport. Staff members release the large, air-breathing reptiles back into the sea when they seem healthy.

Along with Glenn Harmon of the Clearwater Marine Aquarium, Jacobson visited the power plant in June to demonstrate to Quantum staff members and rehabilitation organization representatives how to take blood and process it for testing. He was accompanied by a UF videographer, who filmed the procedure to prepare a video that in several months will be available on the Archie Carr Center Web site to help others.
The project began officially in late July, and the first samples arrived at UF in mid-August for testing. Officials will collect blood from turtles at the power plant, and the sick ones will be retested again at the rehabilitation centers where they are sent.

“While people have been collecting data on turtle blood for years, I believe this may be the largest project of its type in terms of numbers to be sampled,” said Sandy Fournies, a rehabilitation specialist at Marinelife Center. “There have been some published results, but sample sizes are much smaller than for this project.”

Fournies pointed out that the project would also be unique in that its results would be available on the Web.

“Any information that advances our understanding of sea turtles helps us become better at rehabilitation,” she said. “The more data we have on a healthy population, the better we understand what we are aiming for with recovering turtles. Ideally, this results in a greater chance of survival for the turtles we treat.”

Jacobson has two veterinary students working on related studies, one of which focuses on how long the average sea turtle stays in a rehabilitation facility for treatment.

“Do blood values help at all in making a determination whether to release an animal? We don’t really know,” Jacobson said. “However, we do hope to keep this project going for a long time and to build on it. For example, a key component in assessing the health status of wild animals is to evaluate health status both in the wild and in captivity. Ultimately, we hope to be able to build on this database to assess the vitality of wild populations of sea turtles.”

Scientists at the University of Florida have launched an ambitious effort to jump start research on at least 237 species of South American birds that migrate north in the winter with a goal not only of counting and monitoring their populations, but understanding their habitat requirements in both their “homes” - where they breed and where they winter - in order to aid conservation efforts.

Although North American birds that journey south are well researched, little is known about austral migrating birds. This is largely because U.S. and Canadian scientists have focused on native birds, and South American scientists have received much less financial and government support, UF researchers say.

“Very little field work has been done on this subject, which is ironic because South America is known as the bird continent,” said Alex Jahn, a UF doctoral student in ecology, explaining that South America is home to 3,000 species, compared to North America’s roughly 650 species.

In general, austral migrants are birds that breed in Argentina in the South American summer and fly north across the Tropic of Capricorn to winter in northern Bolivia or other points north, though they do not come as far as the United States, said Doug Levey, a UF professor of zoology. They include ducks, sparrows, flycatchers and swallows, he said, and unlike most of their North American counterparts, many appear to be “partial migrants,” with some members migrating and others staying put.

That complexity - and the general health of the birds’ populations - is among the many relatively unknown and intriguing issues surrounding the birds, he said. Others include the birds’ contributions to the health of the larger ecosystem and their potential to carry disease, Levey said.

“West Nile Virus in the Northern Hemisphere is definitely spread by birds,” he said. “It’s quite likely that there are similar sorts of diseases spread by birds in South America, but currently we don’t know enough about bird movements there to assess this possibility.”

Supported by a grant from the National Science Foundation, Jahn and Levey sponsored the world’s first scientific symposium on austral migration last fall, attended by scientists from both North and South American. The two also launched a Web site, http://www.zoo.ufl.edu/ajahn/, aimed at promoting the study of the phenomenon. And this fall, Jahn will journey to Argentina and Bolivia to begin research on austral birds for his doctoral dissertation.

But keeping Fido and Fluffy happy, healthy and away from holiday hazards can be a challenge amid the season’s temptations, edible or otherwise, University of Florida veterinarians warn.

Each year, thousands of pets are treated for holiday-related injuries or illnesses, ranging from severe digestive troubles prompted by eating fatty foods or sweets to tangles with tree-trimming tinsel and other decorations. Although no national statistics are known to exist on the precise frequency of celebration-related pet health problems, UF veterinarians say it’s natural that those who eat, drink and make merry should take extra precautions to avoid pitfalls that can affect household pets.

“The most common thing we see around this time of year is pancreatitis, a sometimes-fatal inflammation of the pancreas that can result from eating high-fat foods like turkey skin,” said Chris Adin, a veterinary surgeon at UF’s Veterinary Medical Teaching Hospital and an assistant professor at the College of Veterinary Medicine. “Severe abdominal pain, vomiting and diarrhea can result.”

Does this mean Rover can’t get the occasional turkey table scrap?

“Probably not a good idea,” Adin said. “Gastrointestinal problems are always a risk when animals eat things they don’t normally have in their diet.”

Save the turkey and ham bones for soup: Bones can become stuck in a pet’s throat, stomach or intestinal tract. Avoid giving animals eggnog, champagne or other alcoholic beverages. And give your pets real kisses, not chocolate ones, over the holidays. Chocolate contains a caffeine-like chemical, theobromine, that can be toxic to animals.

Certain plants, such as holly and mistletoe, also are poisonous. The sap and leaves of the poinsettia can irritate the mouth and trigger severe stomach upset, while various lilies can cause kidney failure in cats if eaten. Ribbons, wrapping paper and tinsel also attract playful pets, who may swallow them. These objects can easily become stuck in the gastrointestinal tract.

“As a surgeon, I see a lot of what we call foreign body obstruction, when cats eat tinsel or other strings, for example,” Adin said. “A linear foreign body that saws back and forth on the intestines potentially involves surgery to remove it.”

Experts offer these pet-proofing tips:

• Firmly anchor your holiday tree to withstand cats that climb or dogs that jump-or engage in powerful tail-wagging.
• Steer clear of using preservatives in a tree stand’s water basin, including homespun additions like sugar or aspirin, all of which can cause nausea or vomiting.
• Place sharp ornaments or fragile decorations out of reach.
• Make sure puppies and kittens don’t use electrical cords and light strands as chew toys.
• Never leave lighted candles unattended.

If you’re planning on going over the river and through the woods-by air or by car-to grandmother’s house and taking Rover along, it’s probably best to acclimate him to a crate if he’s not accustomed to it. Any stress experienced by pets during travel could be exacerbated if they have to be confined to a crate, especially if they aren’t used to it, said Kris Cooke, an assistant professor of small animal medicine at UF.

“Some people will travel with their pets, and depending on where they are going, the airlines will have certain restrictions,” she added. “It’s probably a good idea not to feed animals that morning if they’re going to be flying.”

Checking with airlines ahead of time is the best way to plan ahead to minimize stress on the animals, Cooke said.

And finally, keep an eye on the door when greeting your guests and make sure your pets are wearing identification. An open door can be an open invitation for a quick escape. And consider placing pets in a quiet, secluded part of the house when festivities are in full swing.

Funded by the National Science Foundation, the Florida-based project is one of the largest of its kind ever awarded for this type of research involving wild animal disease as a model for understanding not only the impact on humans but on the entire ecosystem.

“The tortoise is unique, as it has about the same life span as a human and reaches reproductive age at about the same time,” said Mary Brown, a professor of pathobiology at UF’s College of Veterinary Medicine and a principal investigator. “Lots of changes have occurred in the tortoise’s habitat, many of which are human-induced. We are interested in learning more about how natural factors combine with human-induced ones, such as relocation and fire exclusion, and how those relationships interact with biological and microbial factors to determine the incidence and spread of disease.”

In the first year of the new project, a team of experts led by Brown and colleague Paul Klein will survey more than 700 tortoises at 30 Florida sites to determine population characteristics, habitat quality and upper respiratory tract disease status at each location. The sites include state parks, water management areas, military reserves, state mitigation parks and private holdings.

In subsequent years, they will focus on 12 of these sites using ecological, molecular and other diagnostic tools to determine the influence of anthropogenic, or human-induced, factors in disease spread and virulence. Researchers expect these multidisciplinary approaches to shed light on how respiratory disease in its various stages affects gopher tortoise populations. They also hope to develop mathematical models in order to predict the effect these multiple, complex factors have on disease spread.

“Infectious diseases are an ever-present risk to wildlife, particularly during situations in which animals are removed from their natural habitats for captive breeding programs or during conditions of stress, such as release into new habitats or encroachment into their habitats by urbanization,” Brown said. “This is even more important when the species concerned is a keystone species, such as the Florida gopher tortoise, that is critical to ecosystem health.”

As many as 360 animal species depend on the gopher tortoise for survival, including other threatened species such as the indigo snake.

“Without the gopher tortoise, the biological diversity of upland habitats would be greatly diminished,” said Klein, a professor and comparative immunologist in the UF College of Medicine who has a joint appointment in the veterinary college’s department of pathobiology. “Furthermore, in a long-lived species that does not attain reproductive maturity for 10 to 20 years, a single catastrophic event such as a disease epidemic could reduce a population to the point that recovery would be extremely difficult.”

Such an event has happened to the threatened desert tortoise of the American Southwest, according to Kristin Berry, a biologist with the U.S. Geological Survey who first brought the respiratory disease, called mycoplasmosis, to the attention of the UF group a decade ago.

“We have experienced catastrophic declines,” Berry said. “We have lost at least 90 percent of our breeding tortoises in some populations, and in some of these groups, mycoplasmosis has played a role. It’s going to take decades, if not centuries, for us to see recovery.”

Brown, Klein and others at UF who have studied this disease in both the gopher and desert tortoises, were first to identify the mycoplasma bacteria as the disease-causing agent. The group amassed data on several key populations of the gopher tortoise in Florida, “an important foundation for the current research,” Brown said.

“It is exciting that the National Science Foundation is realizing the role of disease in the ecology of wildlife,” Brown said. “They are recognizing that in general, microbial infections in wildlife populations could have an impact on human populations, and that understanding how the disease spreads and what factors affect microbial virulence is very important.”

She added that the UF team’s overall goal is to provide better information to state and federal wildlife management agencies in order to assist them make decisions. In addition to Brown and Klein, experts in reptile medicine and biology, habitat assessment, population dynamics and modeling are contributing to the project.

“If we can provide better answers regarding the impacts of tortoise relocation, for example, these agencies might be able to make better management decisions,” Brown said.

The U.S. Department of Agriculture granted a license last week that will enable Kansas-based Fort Dodge Animal Health to market the product developed by Janet Yamamoto, a professor at UF’s College of Veterinary Medicine who co-discovered the feline immunodeficiency virus. The FIV vaccine is expected to be available to cat owners - through their veterinarians - as early as this summer. Fort Dodge Animal Health is a division of New Jersey-based Wyeth pharmaceuticals.

“This is the first product to ever be made available for preventing this viral infection,” said USDA spokesperson Jim Rogers. “For that matter, it’s the first time any type of vaccine to prevent any type of animal immunodeficiency virus infection has ever been approved for commercial use.”

FIV has many biological similarities to the human immunodeficiency virus, or HIV, the cause of human AIDS. For that reason, strategies and procedures for protecting cats from FIV are expected to aid in the development of human AIDS vaccines.

FIV attacks a cat’s immune system, causing AIDS in cats worldwide. Between 2 percent and 25 percent of the global domestic cat population is believed to be infected with the virus, according to the USDA. The numbers vary due to geographic region, ages of the cats, whether they are kept outdoors and other health problems they may have.

“It is generally believed that transmission of FIV takes place through bite wounds inflicted during fighting, and no cat-to-human transmission has ever been reported ages of the cats, whether in the literature,” Yamamoto said. “However, we are looking into this possibility.”

She added that cats with FIV develop symptoms in three stages.

“In the acute initial stage, cats show loss of appetite, transient fever, lethargy and have a low white blood cell count,” Yamamoto said. “Many cats recover from the initial phase and become lifelong carriers of the virus.

In the second stage, the cats exhibit no overt symptoms. In the third stage, however, cats experience severe weight loss, and secondary infections that become resistant to treatment or frequently recur.”

Yamamoto’s vaccine technology is based on viruses from cats called “long-term nonprogressors,” so named because the animals have been infected with FIV but take a long time to show symptoms of the disease.

“This vaccine is truly international and unique because it is composed of two different FIV strains from two different subgroups of the virus from both the United States and Asia,” Yamamoto said. “These strains take a long time to cause disease, and once symptoms do occur, the disease is milder.”

This interests Yamamoto because she believes long-term nonprogressor cats are probably capable of mounting effective immune responses against the FIV virus, since the virus takes so long to cause disease.

“Instead of rapidly destroying the immune system, the virus hangs around at low levels in these cats and stimulates the immune system, allowing it to respond more effectively,” said Yamamoto, whose research has received grant support from the National Institutes of Health.

“Dr. Yamamoto has always been in the front line of research about FIV and the development of vaccines against feline AIDS, starting from the first identification of the virus in 1986,” said Dr. Mauro Bendinelli, a professor at the University of Pisa in Italy.

“Her achievements in the area are indeed outstanding. The fact that USDA has approved Janet’s FIV vaccine for commercial use is an extremely important step forward in the area of vaccines against lentiviruses in general, since it represents the first vaccine to be considered of practical value by an official regulatory body,” Bendinelli said. “I expect this will boost interest in the development of other lentiviral vaccines, including HIV.”

Dr. Steve Chu, senior vice president for global research and development at Fort Dodge Animal Health, called Yamamoto’s vaccine technology, “a scientific breakthrough for lentivirus vaccine and disease prevention.”

Yamamoto first discovered the virus in 1986 along with a former colleague, Dr. Niels Pedersen of the University of California, Davis. Yamamoto has continued to study the virus and its pathogenesis, which provided the foundation for developing the vaccine.

UF and the Regents of the University of California jointly hold the patents for the FIV vaccine, and the two institutions have reached agreement with Fort Dodge to explore the use of the FIV vaccine for commercial applications, according to Bin Yan, assistant director of life sciences at UF’s Office of Technology Licensing.

“In our experience, a vaccine made using my approach is safe,” Yamamoto said. “However, it is critical that further studies of our vaccine take place on an international level to assess whether protection against worldwide strains of feline AIDS is possible, and whether vaccines composed of viruses from these long-term nonprogressor cats are effective.”

It was as if the lumbering sea cows had a sixth sense that kept them posted on his location. Now, Marshall, who did his doctoral research at the University of Florida, and two UF colleagues think they’ve discovered exactly what that sense is.

In a paper accepted last month at the journal Brain, Behavior and Evolution, the researchers argue that manatees use small hairs on their body as “tiny antennas” that pick up information about water currents, nearby landscape and the presence of other animals. Such an “underwater distance tactile system” is found in fish, which monitor underwater surroundings through sensory pores set along their bodies in twin lateral lines. But the results represent the first time such a system has been documented in mammals, the scientists say.

“In the underwater environment, if you don’t have echolocation, and most of the time you’re in a situation where the water is not all that clear, then another option is to use the tactile sense,” said Roger Reep, the paper’s lead author and UF associate professor of physiological sciences affiliated with the UF College of Veterinary Medicine and the Evelyn F. and William L. McKnight Brain Institute.

“Fish use their lateral line to detect movement and objects in the environment, and we’re arguing that manatees are doing something similar with tactile hairs.”

Although many Florida residents see manatees in Florida’s clear springs, they spend most or their lives in water stained by tannins or clouded with sediment, said Marshall, now an assistant professor of marine biology at Texas A&M University.

Researchers have long puzzled over how manatees, which have relatively poor vision, find their way in these conditions, he said. Also puzzling to scientists: manatees’ proclivity for taking advantage of water flow. For example, manatees often swim from an estuary into a river just as the tide starts coming in, Marshall said.

In research beginning in the early 1990s, the UF scientists focused first on manatees’ unusual facial hairs, known as vibrissae.

That research, which has appeared in Marine Mammal Science and other journals, showed that manatees use the vibrissae both as tools to grasp plants to eat and as sensory organs. Although only the long hairs near their mouths are used for grasping, the sensory hairs are distributed all over their faces, which is very unusual for mammals, Reep said.

“If you look at cats and dogs and most other mammals, their whiskers are largely limited to what you might call the moustache area,” Reep said. “Manatees have these hairs on nine distinct regions of their faces.”

The findings prompted the scientists to probe the role of hairs on the rest of the manatee body — hairs that are so sparsely distributed their function clearly is not to keep the animal warm, Reep said. The scientists examined the anatomy surrounding individual hairs by dissecting carcasses of manatees that had been killed in boat collisions and stored at the Florida Marine Research Institute’s necropsy laboratory in St. Petersburg.

Sure enough, the scientists found that each hair on the body is a tactile hair, with a specialized follicle and dense nerve connections. If these are anything like tactile hairs in other animals, they are surrounded by motion detectors called mechanoreceptors, with nerves connecting to the brain, the researchers said. Margaret Stoll, a biological scientist at UF, participated with Reep and Marshall in the latest research.

“When a hair is deflected, the mechanoreceptors on that side get squeezed, and they send a signal through network of nerves to the brain,” Marshall said. “So it’s a really an integral part of the sensory system of the animal.”

A major killer of manatees is collisions with boats. Marshall said the animals’ unique antenna system is no help in these circumstances, because it is only sensitive to the environment near the animal, meaning if boats are traveling too quickly the animals will receive the information too late to respond.

However, he said, learning about the antenna system may indirectly help managers save manatees, which are protected by the Endangered Species Act.

“No one knows how these animals dig down into the substrate to get at the roots they eat, and my idea is they’re doing it with these vibrissae around their mouths,” Marshall said. “So this study is allowing us to understand the natural history of the animal, and by understanding the natural history we can better manage and protect it.”

The 12-week program, now under way, involves a series of videotaped lectures in which UF veterinarians are teaching 53 foreign veterinary graduates how to prepare for the written portion of the licensing examination they must pass if they intend to practice in this country.

“All veterinary graduates must take this test, which is known as the North American Veterinary Licensing Examination, or NAVLE,” said Carlos Risco, an associate professor in the UF veterinary college’s Food Animal Service.

The course came about largely through the efforts of Sergio Vega, immediate past president of the Dade County Veterinary Foundation, who contacted administrators at UF and within the veterinary college. Vega, who is a member of the Department of Business and Professional Regulation’s board of veterinary medicine, convinced UF’s team that such a course would be a win-win for all involved.

“There was such a need,” Vega said. “These foreign veterinarians do not have any type of study guide. They come in from other countries and are faced with having to take the exam, but don’t know how to prepare for it.”

About 30 of the course participants are from Cuba, Vega said. Others come from Venezuela, Mexico, Peru, Ecuador and Puerto Rico. Topics covered in the course run the gamut from small and large animal medicine and surgery to bacteriology, pathology, immunology, pharmacology, radiology, infectious diseases, ophthalmology, foreign animal diseases and more –- everything veterinarians in a typical D.V.M. program are expected to know when they sit for their licensure exam.

“Originally, we were told we needed 30 people to make this work,” Vega said. “I managed to come up with 53, and there are others who would have signed up if they had been aware of it. I’m really hoping this course is a success, as I would love to see it continue.”

Class participants finish their coursework in March. They will take the licensure examination in April, he added.

From the UF veterinary college, Dr. Paul Gibbs, former director of UF’s International Center and a professor of infectious diseases, has been instrumental in pulling the course together with Risco’s assistance. The Institute of Food and Agricultural Sciences provides the teleconferencing capability.

“This is probably the most ambitious project we’ve ever done, from the standpoint of getting all of the UF veterinarians here to tape their presentations, and then back again for the live question-and-answer taping session,” said Ron Thomas, coordinator of distance education for IFAS Communication Services.

Thomas said 30 presentations are taped, and 60 copies made of each videotape. The tapes are then sent to Vega, who distributes them to each class participant. The foreign veterinarians then view the tape individually, and then again collectively at Nova, which provides a room with teleconferencing facilities for each session. At the end of the video, the professor featured on the tape appears for a 30-minute, live question-and-answer session.

“This type of teleconferencing collaboration with another university is also unique for us,” Thomas said.

Gibbs makes regular trips to South Florida to keep participants motivated.

“The detail of the questions asked of our faculty during the question-and-answer sessions indicates that the veterinarians involved in this course are working very hard,” Gibbs said. “Since many, if not all, have other jobs during the day and they must drive an hour each way to and from Nova University, they are definitely burning the midnight oil.”

One of the participants, Yolanda Melendez, works as a veterinary assistant at Parrot Jungle and Gardens in Miami. In a recent letter to the UF veterinary college dean, Joseph DiPietro, who also has been directly involved in setting up the course, Melendez called the classes “very specific and well organized” and Nova’s facilities “excellent and very modern.”

Her one problem: not enough time for the Q-and-A.

“We have so many questions; we would love to have another hour,” Melendez wrote. “But the professors are giving us their e-mail addresses, so we can communicate with them.”

The Virtual Anesthesia Machine program, dubbed “VAM” for short, is available for free on the World Wide Web at http://www.anest.ufl.edu/vam. It simulates the inner workings of an anesthesia machine and ventilator-the complex machinery in which oxygen, nitrous oxide and anesthetics mix to render patients insensitive to pain during surgery and other procedures. The designers’ goal is to increase patient safety by arming the next generation of anesthetists with a clear understanding of the flow of gas within the equipment and the consequences of machine malfunctions or user actions on pressures, flows, and volumes and composition of gases in the anesthesia machine.

“They say a picture is worth a thousand words. We take it a step farther and postulate that an animation is worth a thousand drawings,” said Sem Lampotang, an associate professor of anesthesiology who together with Dr. Edwin Liem, David Lizdas and Walter Dobbins designed the interactive animation based on earlier work by Dr. J.S. Gravenstein, Dr. Michael Good, and Lampotang.

A 1999 Institute of Medicine report estimated that medical errors cause between 44,000 and 98,000 deaths annually in the United States. Malfunctions in the anesthesia machine and its ancillary equipment, when combined with a failure to properly check the anesthesia machine before use, may contribute to some of these medical errors. Human error and equipment malfunctions are estimated to lead to critical incidents in approximately one in 200,000 cases in which anesthesia is administered.

“Just like a pilot has to do a cockpit check before taking off, an anesthesiologist is supposed to perform a machine pre-use check before anesthetizing a patient to make sure all the components are working as they should,” said Lampotang, who is based at the Evelyn F. and William L. McKnight Brain Institute of UF.

The Food and Drug Administration recommends that such a check be conducted. “Among other learning objectives, the tutorials included in the Virtual Anesthesia Machine Web site explain the FDA pre-use check,” Lampotang said. “A better understanding of the anesthesia machine facilitates proper and expeditious execution of this check.”

At the world’s largest international scientific meeting of anesthesiologists last October, the Virtual Anesthesia Machine won the American Society of Anesthesiologists’ prize for best scientific and educational exhibit and the Anesthesia Patient Safety Foundation’s award for the best patient safety-related scientific exhibit. The VAM Web site receives thousands of visitors each month. Anesthesia instructors in New Zealand, France and many parts of the United States report they are using the program in their courses.

“I refer every resident I teach to the VAM Web site,” said Dr. G. Alec Rooke, a professor of anesthesiology at the University of Washington in Seattle. “For many years I have given residents a tutorial on the various types of gasses, but the lesson was hampered by the lack of a visual illustration of the flow of gas through the system. The Virtual Anesthesia Machine elegantly provides such visualization. The simulator clearly demonstrates the changes in gas movement during inhalation and exhalation and effectively dispels common misperceptions. It’s an incredibly useful teaching tool.”

The Virtual Anesthesia Machine depicts lungs, dials, gas canisters, pipes, ventilator settings and anesthetic agents. Color-coded circles flow through the pipes to represent molecules of oxygen, carbon dioxide, air, volatile anesthetics and nitrous oxide. Dials can be adjusted, valves opened and closed, and rates and directions of gas flow changed. Just as significantly, users are allowed to adjust the controls improperly - for example, excessively inflating the lungs - and therefore can learn from their mistakes. Equipment faults also can be simulated.

“Students have been learning how to operate an anesthesia machine by looking at static pictures in textbooks and during lectures. The crucial dimension of time is missing from these static pictures. And that’s a lot of knowing how to use the machine and timing interventions appropriately,” Lampotang said.

The Virtual Anesthesia Machine is not the first major teaching tool Lampotang has developed. He was part of the UF team that developed and refined the Human Patient Simulator over the past 15 years. The Human Patient Simulator features a lifelike, programmable mannequin that can be used to train health-care personnel how to respond to various medical emergency scenarios. Academic centers throughout the world, including UF and Santa Fe Community College in Gainesville, use the simulator to teach students.

“A major advantage of simulation is that you can focus on learning without being distracted by the concern of placing an actual patient at risk,” Lampotang said.

With the new technique, pets can be treated in one session of high-dose, precisely targeted X-ray treatment, rather than through repeated sessions over a period of weeks.

“So far we’ve done a total of 22 animals, including both dogs and cats,” said Nola Lester, a clinical instructor in radiology with the UF College of Veterinary Medicine. “About 20 of those cases have been treated over the past two years, and most have been patients with brain tumors and other tumors in the head region.”

Known as stereotactic radiosurgery, the original method has evolved as the treatment of choice for humans with certain types of intracranial tumors since its inception more than a decade ago. In 1988, Frank J. Bova and Dr. William Friedman, initiated radiosurgery treatments using their patented system known as the LINAC Scalpel. This system assists with localizing, planning and treating intracranial tumors using a specially designed adaptation of a medical linear accelerator. Recently, Bova and Friedman have developed an additional method that uses a three-dimensional ultrasound guidance system to pinpoint tumor location and target radiation beams precisely to tumors in internal organs.

“Radiosurgery has been used to treat certain brain tumors and arteriovenous malformations in people for many years,” Lester said. “We have been able to transfer this technology to animals and are using it to benefit our cancer patients.”

“As far we know, there are no other veterinary facilities in the country, and probably the world, that are doing this procedure on animals,” Lester said. “We are extremely fortunate to be in such close proximity to the Brain Institute and to have people there who are willing to collaborate with us.”

Through precision targeting, stereotactic radiosurgery allows a higher dose of radiation to be given in one session than would be administered during more traditional radiation therapy - and often with better results, Lester said.

Six years ago when she was still a puppy, Cindy was rescued from abandonment and starvation. But that wasn’t the end of the Dunnellon dog’s troubles. When she developed a tumor two years later, salvation came from a pioneering form of radiation therapy developed at the University of Florida.

With one massive but precisely targeted dose of radiation directed at the life-threatening tumor above her eye, UF veterinarians ensured that the mixed-breed dog, owned by Dorothy Schweitzer, would again prevail over adversity.

Another advantage is that animal patients receive a single dose of anesthesia rather than several that would be administered over a period of time during traditional fractionalized therapy, in which several doses of less potent radiation are given in a more general region of the area surrounding the tumor.

“Pet owners having the procedure done here need to bring their pets to the UF Veterinary Medical Teaching Hospital one time, which can be a big advantage, particularly for those who would be traveling long distances,” Lester added.

The procedure is also being used at the veterinary teaching hospital to treat vaccine-associated fibrosarcomas in cats and osteosarcomas in dogs, she said.

“In people, a stereotactic head frame was built to aid radiologists in obtaining their up-to-the-minute computer images, but we found it just didn’t work well in dogs and cats,” she said. “So we adapted a method using a ‘bite plate’ - a dental mechanism - that works much more effectively in animals.”

Lester stressed that the procedure is at times extremely effective, and at times, less so.

“In some cases, we have seen fantastic results and the tumor completely disappears. In others, this is not the case. So we are still in the early stages of figuring out what responds well and what doesn’t.”

The procedure costs approximately $2,200, roughly the same as for traditional veterinary radiation therapy. Certain animals may be eligible for a $700 UF subsidy, in addition to free follow-up care and imaging.

Dorothy Schweitzer’s dog, Cindy, though successfully treated for her eye tumor, subsequently developed an unrelated mass in her spleen, which was surgically removed at UF.

“She is really the miracle dog because she is now considerably beyond the average survival time for both of the unrelated cancers she had,” said Tim Cutler, an ophthalmology resident at the UF veterinary college who was Cindy’s initial clinician.

The finding - that the striped skunk and nine-banded armadillo play key roles in hosting the parasite that causes equine protozoal myeloencephalitis, or EPM - may lead to improved control of a disease that, according to the most recent National Animal Health Monitoring System survey, cost the U.S. horse industry $27 million in 1998.

“Basically, horses become infected with the parasite that causes EPM by eating feed or drinking water that is contaminated by stages of the parasite released in opossum feces,” said veterinary researcher Andy Cheadle, whose findings appeared in the April and June issues of the International Journal for Parasitology. “What we’ve found is that opossums can become infected by eating skunk and armadillo muscle that contains the parasite.”

The message to horse owners: Control the opossum, skunk and armadillo population on your farm. “The single most important animal to remove would be the opossum,” said Cheadle, who recently received his doctorate from the University of Florida.

Each year, several thousand new cases of EPM are reported, with 14 out of every 10,000 horses in the United States developing the disease, according to the National Animal Health survey. The number can be as high as 60 cases per 10,000 in performance horses, said UF equine medicine Professor Rob MacKay. No reliable estimates are available for how many horses live with the condition, but studies have shown that only 40 percent of horses appear to recover completely.

“In some horses, the signs may be very subtle and difficult to distinguish from a musculoskeletal problem or an obscure lameness,” said Stephen Reed, professor and head of equine medicine and surgery at The Ohio State University College of Veterinary Medicine. “Many affected horses show muscle wasting and profound weakness.”

Treatment for the disease involves the use of various medications, as well as other therapies that may act to increase the horse’s natural defense mechanisms, Reed added.

The parasite’s life cycle has confounded scientists nationwide who have worked diligently in recent years to identify all the stages of the disease cycle and be able to reproduce the disease in horses in order to better study it.

The opossum’s role as a definitive host for the parasite, a single-celled organism called Sarcocystis neurona, has been known since a 1995 discovery by University of Kentucky researchers. The animal that the opossum was eating to become infected remained unknown.

UF scientists have maintained an extensive EPM research program since the mid-1990s seeking to identify the intermediate hosts of the EPM parasite. Molecular tools developed by UF researchers Susan Tanhauser and John Dame helped lay the groundwork for further studies conducted by the EPM group.

While working in the laboratory of UF researcher Ellis Greiner, graduate students developed the idea of establishing an unusual “road-kill hot line” to investigate the program. Radio ads encouraged residents of Central Florida to phone the hot line when they spotted dead opossums along the roadside. Student assistants were charged with the unenviable task of collecting the opossum remains for scientists to gather samples of the EPM parasite.

“We’ve always wanted to know what the opossums were eating to become infected,” Cheadle said. “The intermediate host continues the life cycle of the parasite and makes it available to the opossum, so without it, the opossum would not become infected and pass the parasite on to the horse.”

After evaluating many different kinds of animals, Cheadle found that opossums became infected with, and released, S. neurona in their feces after being fed infected armadillo muscle. Colleagues at Washington State University fed the parasites to a horse, which developed antibodies to the parasite and transient EPM.

“It was very important to show that the parasites we collected from opossums fed armadillo muscle would cause clinical signs in the horse,” Cheadle said.

Cheadle also found that the striped skunk was in intermediate host to S. neurona. Skunks, deliberately infected with the EPM parasite, developed sarcocysts of S. neurona in their muscles. Opossums fed these infected skunk tissues produced the stage of the parasite infective for horses.

Researchers suspect that other animals, including the brown-headed cowbird and the domestic cat, may also play a role in the parasite’s life cycle.

“We now have methods for producing the parasite, which paves the way for further development of animal models, as well as new molecular tests, vaccine development and treatments for the parasite,” Cheadle said.

The UF study was supported by grants from the Florida Department of Business Regulation’s Division of Pari-mutuel Wagering and the U.S. Department of Agriculture.