• UF study shows long-term drug abuse starts with alcohol
• UF scientists find state record 87 eggs in largest python from Everglades
• University of Florida astronomer reports rare case of gravitational lensing
• UF report: 2011 shark attacks remain steady, deaths highest since 1993
• UF researchers develop “nanorobot” that can be programmed to target different diseases
• New UF study shows early North Americans lived with extinct giant beasts
• UF’s Gator Marching Band makes history in London
• Search Committee Appointed to Recruit New UF President
• UF veterinary researchers discover new virus linked to death of Australian snakes
• UF trustees OK naming building, business school for Heavener

University of Florida veterinarians identified the parasite, called Leishmania siamensis, in summer 2011. This particular species of parasite previously had been found only in Thailand and parts of Europe. No Leishmania infections of any species had been previously reported in a horse native to the United States.

The UF discovery raises awareness of how widespread the parasite is and suggests a need for watchfulness regarding potential transmission to humans, the researchers said.

“We now know the parasites that cause this disease also exist here in the U.S. and that we have some insect, presumably the sandfly, that is capable of transmitting the disease,” said Sarah Reuss, a clinical assistant professor of large animal medicine at the UF College of Veterinary Medicine. Reuss, UF colleagues and a private practice clinical pathologist described the findings in the September issue of Emerging Infectious Diseases, a journal of the Centers for Disease Control and Prevention. “Our findings raise several potential avenues of further investigation, including the prevalence of this disease in horses in the U.S., a better understanding of the sandfly life cycle and the potential of this leishmaniasis species to be transmitted from animals to humans,” Reuss said.

Leishmaniasis is a parasitic infection spread through the bites of infected sandflies. The disease shows up most commonly in two forms: cutaneous, which causes sores on the skin and is self-healing; and visceral, the most severe form, which affects the entire body and is almost always fatal if left untreated.

After malaria, leishmaniasis is the leading parasitic cause of death in humans. The disease has been found in four continents and is considered to be endemic in 88 countries, including 16 developed nations, according to the World Health Organization. The WHO estimates the worldwide prevalence at 12 million cases, with about 350 million people at risk of infection and about 60,000 people dying from the disease each year. Leishmaniasis is rare in people in the U.S.

“It really hasn’t been a disease that has affected Americans, but there are really good data with climate change models that predict sandfly ranges will expand, making this disease much more of a threat because of global warming,” said co-author James Wellehan Jr., a veterinarian from the UF research team, who confirmed the presence of the disease in the Florida horse by analyzing the genes of the parasite.

The visceral form of leishmaniasis is endemic in foxhounds in the U.S, associated with a parasite species different from the one found in the Florida horse. But aside from some regional transmission in the Southwest, most of the leishmaniasis skin infection cases in the U.S. are believed to have occurred in animals brought in from countries where the disease is common, or in people who had recently spent time in those countries.

“Thousands of people serving in the U.S. military have returned from Iraq and Afghanistan with cutaneous or visceral leishmaniasis,” said Christine Petersen, an associate professor of veterinary pathology at Iowa State University’s College of Veterinary Medicine and an expert on Leishmania transmission, immune responses and veterinary disease, who was not involved in the study. “In a few cases, these individuals have brought dogs back with them that also have leishmaniasis.”

But the horse diagnosed at UF had no history of travel outside of the eastern U.S. The pregnant 10-year-old Morgan mare was treated as an outpatient at the University of Florida Large Animal Hospital for sores inside her left ear. A biopsy done in the field revealed what looked like the rare parasite within inflammatory cells in the tissue. Further tissue sampling and genetic analysis were used to confirm the identity of the disease-causing organism.

Often, leishmaniasis of the skin will resolve without medical treatment. But the mare’s sores worsened over time — a development the veterinarians attributed to the pregnancy.

“Many of the horses in other countries that have been diagnosed with leishmaniasis were pregnant, so we think perhaps these horses have pregnancy-altered immune systems and are therefore more vulnerable to the disease,” Reuss said.

The drug used to treat horses with the disease in other parts of the world isn’t readily available in the U.S., and surgery wasn’t an option because the sores were inside the horse’s ear. After treatment with anti-fungal drugs, the sores eventually regressed.

Horses housed at home with the affected horse did not show any signs of illness. Though the disease needs the blood-sucking sandfly as a carrier and does not pass directly among horses or between horses and humans, veterinary experts say the discovery of the new parasitic species in the U.S. is cause for increased vigilance.

“As a disease of animals capable of being transmitted to humans, leishmaniasis requires more attention to ensure we do not have vector-borne transmission within larger areas of the country,” Petersen said.

The researchers found that the bacteria, known as Mycoplasma canis, invade dog’s cells and suppress their immune system responses.

“This could explain how the bacteria are able to enter the brain in certain circumstances,” said lead investigator Daniel Brown, an associate professor of infectious diseases at the UF College of Veterinary Medicine. “If our theory is correct, it is possible that antibiotic therapy aimed at the mycoplasma could be beneficial if the condition is diagnosed early enough.”

The findings, which appear in the August issue of the Journal of Bacteriology, were also presented at the annual meeting of the International Organization for Mycoplasmology in France.

The researchers studied two common brain syndromes called granulomatous meningoencephalomyelitis, or GME, and necrotizing meningoencephalitis, or NME, which occur primarily in small toy-breed dogs such as pugs, Malteses, Yorkshire terriers, Chihuahuas and Pomeranians. The diseases affect the central nervous system, causing brain damage and symptoms such as seizures, decreased alertness and difficulty maintaining balance. There is no cure, but drugs can control the brain inflammation by suppressing the immune system.

No clear data exist on how widespread the disorders are.

“Although reliable information on new and existing cases is pretty scarce or nonexistent, inflammatory central nervous system disease is certainly one of the most common problems we deal with as veterinary neurologists,” said Christopher Mariani, D.V.M., Ph.D., an assistant professor of neurology at North Carolina State University’s College of Veterinary Medicine. Mariana was not involved in the UF study.

The syndromes previously were thought to be caused by a virus or by an attack of the body’s own immune system. But University of Georgia researchers Renee Barber, and Scott Schatzberg, and colleagues, including Brown, reported earlier this year that whereas viruses were absent from the brain tissues of dogs with the diseases, the bacterium Mycoplasma canis was unexpectedly common. Interestingly, the researchers also found traces of the bacteria in some dogs that did not have the disease.

The bacteria would not have been detected by the methods used previously to search for a presumed viral agent.

In the new study, Brown and colleagues examined five strains of Mycoplasma canis isolated from three different parts of the body — the brain, the genital tract and the throat.

They found no difference between the genetic makeup of the bacteria from brain tissue and that of the bacteria from other sites.

What they did find was evidence that the bacteria don’t just sit on the surfaces of cells, but actually penetrate inside cells. That may be what enables entry into the bloodstream and eventually, to the brain, the researchers said.

“This finding is tantalizing, because it may offer an explanation as to why scientists have never been able to specify a viral, autoimmune or other cause of GME and NME,” Brown said.

In addition, different strains of bacteria were not equally efficient at suppressing the dogs’ immune responses.

The researchers are continuing to analyze the effects of bacterial infection on immune system cells known as macrophages to determine how the bacteria could breach the blood-brain barrier. Later, they will extend their studies to examining how the bacteria interact with different types of brain cells.

“The study is intriguing, but more work needs to be completed to determine the significance of these bacteria as a possible cause of GME and NME,” said Karen Vernau, an associate clinical professor and chief of neurology/neurosurgery at the University of California, Davis’ College of Veterinary Medicine, who was not involved in the study.

Dubbed the “Sunshine virus” because of its discovery in Australia’s Sunshine Coast region, the organism causes nervous system and respiratory disease and is the first of its kind to be identified. Although it is in the same overall family as other viruses that affect snakes and lizards, the Sunshine virus doesn’t fit into existing subgroups of viruses.

The discovery, described online and in the upcoming October 2012 print edition of the journal Infection, Genetics and Evolution, might help scientists better understand the biology and origin of an important group of disease-causing organisms and inform efforts to prevent future outbreaks.

“Understanding the ecology and diversity of infectious diseases of wildlife is critical,” said co-author James Wellehan, an assistant professor of zoological medicine at the UF College of Veterinary Medicine. “While medicine has traditionally waited for big outbreaks to cause large numbers of deaths and then dealt with new diseases reactively, an understanding of what viruses are out there and how they can be expected to behave allows us to be proactive, being aware of and monitoring agents of potential concern.”

The emergence in recent years of deadly new viruses that attack humans has raised concerns regarding transmission between wildlife, livestock and humans. For example, the Hendra and Nipah viruses caused high rates of death in Australia and Indonesia in the 1990s, not just among horses and pigs but also among humans.

The quest to identify the new virus started as an investigation of the cause of a 2008 disease outbreak in a privately owned Australian collection of 70 pythons. As more and more animals became sick, showing signs of pneumonia, depression, lethargy and abnormal behavior such as “star gazing” — staring up at things — they were all eventually euthanized.

The researchers had great difficulty detecting the elusive virus and struggled to identify the category in which it belonged.

“We screened more than 450 samples, including swabs, tissues and blood for snake viruses,” said lead author Timothy Hyndman, a lecturer and graduate student at Murdoch University in Australia. “It was very frustrating. After two and a half years, we finally isolated something. A year later, we figured out what it was.”

The researchers infected snake heart cells with virus collected from tissues of the affected snakes and found that it caused the cells to become abnormally large and have more than one nucleus, the cell’s command center.

Using sophisticated techniques for analyzing large numbers of genetic sequences at the same time, the researchers identified several that had limited similarity to known viruses in large genetic databases. They used this information to put together the genetic blueprint of the Sunshine virus. Statistical analyses that allow construction of a “family tree” showed that the Sunshine virus belonged to a family called paramyxovirus. That family contains some of the most significant disease-causing agents in animals and humans, according to the National Center for Biotechnology Information. Measles, mumps and canine distemper are all in the family.

But unlike all known snake and lizard viruses in that family, the new virus did not fit into a subgroup called ferlavirus. The new virus is only distantly related to those viruses.

“This is the first non-ferlavirus paramyxovirus to be discovered from a reptile,” Hyndman said. “In the previous 40 years, reptilian paramyxoviruses were all very similar until this one was discovered.”

Previously known members of the virus family have grouped into two subfamilies. The Sunshine virus fell outside both of those known groups. Inclusion of Sunshine virus in the family tree analysis showed that viruses thought to be in the same subfamilies might not actually share recent ancestors, the researchers said.

“The two subfamilies may need to be split up into distinct families,” Wellehan said.

Although it is likely that the virus was responsible for the outbreak of disease in the collection of pythons, that has not been proved irrefutably.

The study shows off how sophisticated gene sequencing technology can be used to characterize mysterious new viruses and possibly speed up public health responses to outbreaks in humans, animals and plants, the researchers said.

“This virus was invisible to prior technologies,” said Eric Delwart, director of molecular virology at the Blood Systems Research Institute and an adjunct professor of laboratory medicine at the University of California, San Francisco, who was not involved in the study. “Besides providing assays to help track and control outbreaks of this new snake virus, the study highlights the enhanced ability of scientists to rapidly identify novel pathogens.”

“We have demonstrated that our bacterial treatment can take on established colon cancer,” said principal investigator Mansour Mohamadzadeh, a professor in the UF College of Veterinary Medicine department of infectious diseases and pathology and a faculty member in the UF College of Medicine division of gastroenterology, hepatology and nutrition in the department of medicine. “This is huge, because people don’t come to you 10 years before they have colon cancer saying, ‘I may get colon cancer, can you treat me?’ They come to you and say, ‘I have colon cancer.’”

For years researchers have understood that uncontrolled inflammation in the large intestine can result in various diseases, including colon cancer and inflammatory bowel diseases such as ulcerative colitis. The new study focused on understanding how to curb immune system processes in the gut that lead to harmful inflammation. Resulting treatments could work not just for diseases of the digestive tract, but also for other conditions such as diabetes and Sjögrens syndrome in which inflammation plays a major role.

Some inflammation in the gut is a good thing, as it serves to keep the body’s immune system in tip-top, disease-fighting shape. But under stress, the immune system overreacts with a cascade of inflammation-causing reactions. That can lead to afflictions in which the immune system attacks instead of protects the body. It can even cause colon cancer, which kills more than 50,000 Americans every year and is one of the nation’s leading causes of cancer deaths, according to the National Institutes of Health.

Mohamadzadeh, a member of the UF Shands Cancer Center and the UF Emerging Pathogens Institute, and colleagues previously demonstrated that a genetically modified form of the beneficial bacterium Lactobacillus acidophilus can bring overactive immune responses back to normal. They have now found that proteins on the surface of the bacteria can act on the immune system to either cause inflammation in the gut or tune it down.

The researchers removed an inflammation-causing gene from the bacterium, and the result was a form of the bacteria that was even better at controlling disease-causing inflammation. Moreover, mice with severe cases of polyps and cancerous intestinal lesions that were fed the modified bacteria had significantly reduced numbers of colon polyps compared with untreated mice, and showed no signs of active colon cancer or disease-causing inflammation.

“This is a major discovery that defines how ‘healthy’ microbes function in the gut,” said Dr. Eugene B. Chang, the Martin Boyer professor of medicine at the University of Chicago Knapp Center for Biomedical Discovery. Chang was not involved in the UF study. “This has far-reaching implications for the development of therapies derived from microbes that can treat many types of complex immune and digestive disorders.”

The modified bacteria are easy and cost-effective to produce. Mohamadzadeh anticipates that a treatment for humans could be a pill that can be taken by mouth. Patients could receive the beneficial bacterial treatment in combination with surgery or other therapies.

Using gene sequencing technology, the researchers developed a “brain and immunity chip” to characterize molecular changes in the equine brain during illness and recovery from West Nile virus. The findings were published in the journal PloS One in October.

“We hope this will help us understand why some animals and humans become sick and others succumb to the virus resulting in severe illness, lifelong neurological debilitation and even death,” said senior author Maureen Long, an associate professor of infectious diseases and pathology. “Knowing this will allow us to come up with treatments that aid in recovery from illness.”

Lead author and Long’s former graduate student Melissa Bourgeois, created a gene library enriched for neurological and immunological sequences to develop the novel chip, which will help target genes that are active during brain disease states.

A gene chip, or microarray, is a slide with hundreds of pieces of DNA strands arranged in a regular pattern. When those strands, called probes, are exposed to genetic material from equine cells, researchers can identify genes associated with equine brain disease. The UF group relied on Agilent Technologies, based in Santa Clara, Calif., which has patented the probes.

In the end, the equine brain chip consisted of 41,040 genes and included many targets that have counterparts in human psychiatric diseases, such as depression and schizophrenia; and neurodegenerative diseases, such as Parkinson’s and Lou Gehrig’s disease.

West Nile virus is a potentially serious illness often transmitted by mosquitoes. Since 1999, more than 24,000 cases of West Nile virus encephalitis have been reported in horses in the United States, with more than 1,000 cases reported in 2006, according to the American Association of Equine Practitioners. In 2006, there was a 14 percent increase in human cases and new expansion of the virus into 52 U.S. counties.

Long and Bourgeois investigated the basic idea that certain families of genes change expression in a consistent manner during West Nile virus infection, as well as during the disease and recovery from encephalitis caused by it.

“Although we knew there were microarrays that had previously been developed for horses, our goal was to create a brain and inflammation-based array to look specifically at how function was affected during brain infection,” said Long, who is also a member of the UF Emerging Pathogens Institute. “This chip has applications to many brain and spinal abnormalities of the horse including eastern equine encephalitis, equine protozoal myelitis, rabies, and even non-infectious diseases like Wobbler syndrome. This allowed us to detect changes that would not be common in normal horses.”

The UF study took more than five years and relied heavily on sequencing and bioinformatics expertise provided by the university’s Interdisciplinary Center for Biotechnology Research.

“Analysis of the data found that many of the psychiatric, Parkinson genes and neuromuscular diseases were triggered,” Long said. “Then a computer program that can analyze hundreds of genes simultaneously was used to build models of various disease processes that may be affected in the acute disease and may result in other diseases once the infection is long gone.”

Data mining and testing of individual pathways of disease is the focus of current work in Long’s laboratory.

“The wonderful resources and excellent collaborators at the University of Florida will allow us to use the power of comparative medicine to contribute to the biology of brain infection in humans in animals,” Long said.

Bourgeois, who now works in the influenza division of the Centers for Disease Control in Atlanta, said, “Information discovered in this research could eventually be used to combat not only outbreaks of West Nile virus, but also as a model to understand and reduce the impact of viral encephalitis in general.”

Other collaborators include UF’s Nancy Denslow, a professor of physiological sciences; David Barber, formerly an assistant professor of physiological sciences at UF; and Kathy Seino, an assistant professor at Washington State University.

The scientists hope their findings will aid in the registration and use of the vaccine, called GonaCon, to help manage overabundant feral cat populations humanely.

“Millions of free-roaming feral cats exist in the United States and in other countries around the world,” said Julie Levy, the lead researcher and director of the Maddie’s Shelter Medicine Program at UF. “Unfortunately, their welfare is not always adequate, and they can have a negative impact on public health and the environment.

“We’re hoping this research will lead to a nonlethal method of control for feral cat populations that is less expensive, labor-intensive, and invasive than current methods, such as surgical sterilization,” Levy said.

Funded by Morris Animal Foundation, a nonprofit organization that advances veterinary research to protect, treat and cure animals, the five-year study was published in August online in the scientific journal Theriogenology.

GonaCon was developed by researchers at the USDA Animal and Plant Health Inspection Service National Wildlife Research Center. The NWRC is the federal institution devoted to resolving problems caused by the interaction of wild animals and society. The UF researchers involved in the testing do not have any licensing agreements with the USDA or any commercial interests in the vaccine.

In the study, 15 adult female cats received a single dose of the vaccine while five received a placebo. After the injections, the female cats were allowed access to a breeding male cat. All five placebo females became pregnant within seven to 28 days.

Cats injected with the vaccine, on the other hand, remained infertile from five months to more than five years. All of the cats were adopted at the end of the study.

“A total of 93 percent of the cats treated with GonaCon remained infertile for the first year,” Levy said. “In subsequent years, we saw a steady and expected decline in infertility as antibodies to the vaccine decreased. However, numbers were still quite high, with 73 percent of the cats remaining infertile during the second year, 53 percent in year three, 40 percent in year four, and 27 percent in year five when we ended the study.”

Although permanent sterilization is ideal, the relatively short lifespan of many free-roaming feral cats suggests that a contraceptive that blocks fertility for several years may be successful in reducing the population.

Joyce Briggs, president of the Alliance for Contraception in Cats & Dogs, a group advocating for nonsurgical birth control methods, called Levy “a key player in efforts to advance new methods of fertility control.”

“We are intrigued by this study,” Briggs said. “Although a permanent sterilant would be ideal, a long-acting contraceptive could be an effective tool for managing feral cat populations, especially where surgery is unavailable or impractical.”

GonaCon is currently registered by the U.S. Environmental Protection Agency for use on female white-tailed deer; however, the vaccine has also proved successful with numerous other mammal species including feral horses, bison, elk, prairie dogs and ground squirrels.

The single-shot, multiyear vaccine stimulates the production of antibodies that bind to GnRH, a hormone in an animal’s body that signals the production of sex hormones, such as estrogen, progesterone and testosterone. By binding to GnRH, the antibodies reduce its ability to stimulate the release of these sex hormones. All sexual activity is inhibited, and animals remain in a nonreproductive state as long as a sufficient level of antibody activity is present.

In the July issue of Vaccine, UF veterinary scientists report sequencing the genes of multiple strains of the bacteria from across North America to identify common substances that could be candidates for vaccine development.

Anaplasma bacteria infect red blood cells and are estimated to cost the cattle industry $300 million a year, according to industry estimates. Sick animals may develop a fever, have difficulty breathing and may be anemic. Thirty percent of the animals that contract bovine anaplasmosis die.

“At the DNA level, we examined genes to determine how similar they are among various strains of the disease,” said Michael J. Dark, an assistant professor in the college’s department of infectious diseases and pathology. “If they show similarity, they are probably better vaccine candidates because they would presumably offer cross-protection against multiple strains.”

Although many attempts have been made since the early 1900s to develop a vaccine against Anaplasma marginale, none have provided complete protection against infection with different strains of the bacteria, Dark said. Some previous studies have focused on two particular proteins, MSP2 and MSP3, which are known to protect against certain strains, but which have not yielded universal protection.

The research team, including scientist Basima Al-Khedery, and Anthony F. Barbet, a professor of molecular biology, used a technique known as pyrosequencing to compare multiple strains of Anaplasma marginale and determine which showed fewer DNA changes from strain to strain.

“No vaccine has been proven 100 percent effective against all strains, which is necessary for an effective vaccine,” Dark said. “Ideally, the perfect vaccine would also have other characteristics, such as
not needing to be refrigerated; otherwise in places like Africa, you’d never be able to use it. You’d also want a vaccine to be effective quickly and long-lasting, hopefully for the life of the animal, or at least so that it wouldn’t need booster shots every year.”

But the disease is difficult to defend against, for several reasons.

“We already have vaccines for diseases that are relatively easy to produce vaccines for, such as smallpox in people,” Dark said. “The biology of Anaplasma marginale is more difficult to protect against, because the organism has evolved in order to infect cattle for life. Because of its ability to adapt and evade the immune system, this disease has made our lives that much more difficult in terms of trying to find a vaccine that is effective.”

Dark and Barbet are also members of UF’s Emerging Pathogens Institute, a multidisciplinary research endeavor to prevent or contain new or re-emerging diseases.

Jim Handley, executive vice president of the Florida Cattlemen’s Association, said he was excited about the “cutting-edge” research being conducted at UF.

“As with many cattle diseases, Anaplasma continues to offer economic challenges to producers,” Handley said. “Any advancement toward the development of a vaccine against Anaplasma offers huge potential for commercial application.”

Researchers say more is understood about the way in which Anaplasma affects the immune system than is known about many human diseases and even many other tick-borne diseases that affect livestock and other animals.

“Yet, despite that knowledge, we still can’t create a vaccine that protects against every strain,” Dark said.

He added that molecular analysis has given researchers useful tools for examining differences between individual organisms, such as information that could be gleaned to yield important epidemiologic information, or determine disease origin.

“We are starting to get into more of the details as to what makes up the organism, but what is the difference between Anaplasma marginale in Florida and in Puerto Rico, and how can we use genetic information to determine where a disease comes from?” Dark said.

“Does every strain from Florida have certain characteristics? Might something work against a disease found in that state but not elsewhere? We have a lot of questions open up when we can look at all these organisms quickly and fairly cheaply at the genetic level, and we can also get more information than we ever have before.”

“We discovered that dolphins get multiple infections of papillomaviruses, which are known to be linked with cervical cancer in women,” said Hendrik Nollens, a marine mammal biologist and clinical assistant professor at UF’s College of Veterinary Medicine today (Feb. 18) at the annual meeting of the American Academy for the Advancement of Science. “Dolphins are the only species besides humans that we know of that can harbor coinfections, or infections of multiple papillomavirus types, in the genital mucosa.”

There are approximately 100 types of human papillomaviruses, and multiple infections of up to eight HPV types have been reported in humans, he said.

“Even more surprisingly, some virus groups have shown the ability to cross the marine-terrestrial ecosystem boundary — from sea to land,” Nollens said. “We have demonstrated at least one case of genetic recombination between viruses of human and marine mammals. So while it’s exciting that dolphins can provide a unique window into the role of coinfection in human cervical cancer, we can’t rule out that the next high-risk virus, such as SARS, or West Nile, might actually come from the marine environment.”

The presence of coinfections is believed to be one of the biggest risk factors for the development of cervical cancer in humans, Nollens said, although he added that there is no evidence that dolphins develop the disease.

“Why do people develop the disease, but dolphins don’t? If we can figure out why, the human medical community might be very interested in how that information might be applied to human strategies for preventing the disease,” he said.

Of all creatures that inhabit the ocean, dolphins and other marine mammals are the closest relatives of humans, but researchers say scientific knowledge of infectious diseases, particularly viral diseases, affecting these animals is limited.

In hopes of shedding more light on the nature, prevalence and potential of such diseases to be passed to humans, Nollens and his colleagues at UF’s Marine Animal Disease Laboratory have embarked on a large-scale collaborative research project to catalogue previously unrecognized and emerging viruses of marine mammals, both in collections and in the wild.

Over a four-year period, some 1,500 blood, tissue and fecal samples taken from dolphins have been analyzed at different laboratories across the United States, Nollens said. No animals were harmed during collection of cell and tissue samples, although some were obtained from animals that have died of natural causes in the wild.

“Some 90 percent of what we do in the laboratory is molecular analyses,” Nollens said. “Because of advances in molecular medicine since January 2006, we’ve found more than 40 new viruses in dolphins alone. When the last textbook came out in 2003, only 19 were noted.”

All viruses found in the laboratory and suspected of having pathogenic potential are further evaluated to assess the impact each could have on the health of individual dolphins, he added. The information is then used to generate guidelines for disease outbreak management and prevention strategies.

“This process helps us understand disease and disease prevention,” Nollens said, adding that for more than a decade, scientists have been looking for cures to human diseases, including cancer, among marine invertebrates.

“Maybe there will be a similar story with dolphin papilloma viruses and prevention of cervical cancer in humans,” he said. “It wouldn’t be the first time we’ve come up with useful information from looking at marine animals.”

The discovery of new infectious diseases and viruses in marine mammals is important for conservation as well as for a better scientific understanding of the connections between oceans and people, according to Teri Rowles, director of the National Oceanic and Atmospheric Administration’s Marine Mammal Health and Stranding Response Program.

“This work highlights the importance of partnerships in this type of interdisciplinary ‘One Health’ science to allow us to be better stewards of healthy oceans and coasts, healthy marine mammal populations and healthy people,” Rowles said.

GAINESVILLE, Fla. — It’s bad enough that the Southeast is bedeviled by a tick that doesn’t mind taking up residence inside homes.

But now researchers say they believe the brown dog tick has developed resistance to the treatments most commonly used to fight it.

University of Florida researchers Phil Kaufman and Faith Oi will work with USDA tick expert Robert Miller to test the ticks’ resistance to permethrin, a chemical found in many pesticides and repellents, and fipronil, found in Frontline. Both are sold in pet stores.

A $171,000 grant from the USDA’s Southern Region Integrated Pest Management Center will support the researchers’ three-year study. When it ends, they hope to know the tick’s level of resistance to both chemicals and to have an array of materials aimed at teaching the public how best to guard against infestations and what to do if they face one.

The brown dog tick has been invading homes across the Southeast for years, Kaufman said, but its resistance to chemical foes seems to have been building the last five to eight years. This study will be the first to document the ticks’ resistance in the U.S.

“The challenge now is in people not being able to control or knock out the ticks with some of the pesticides,” he said. “And for controlling this particular tick, pesticides are almost essential.”

Having one’s home infested with the brown dog tick is nothing short of miserable. While they’re not generally known for spreading disease to humans, they are often described as “predatory,” lying in wait for whatever organism will provide their next blood meal, whether it be dog – or human.

The ticks are small — about the size of a match head — before they get a blood meal and grow noticeably bigger. Before that, they’re tough to see, leaving homeowners to often miss the first signs of an infestation, especially when even tinier larvae and nymphs are present.

The first indication often comes when residents see ticks crawling up the walls or curtains.

“I always tell people it’s a minimum of a six-month ordeal and oftentimes, up to a year to clear an infestation,” Kaufman said. “One female tick can lay 5,000 eggs. And if you miss one tick, and she lays those eggs — you’re starting over.”

Part of the problem likely lies in pet owners’ good intentions, the researchers say. Pet owners don’t like the idea of pets with fleas or ticks, so they buy pesticides that come in handy one-month doses, and then treat for ticks and fleas whether they’re present or not.

That type of preventative spraying and dosing is typically reserved for pests that can kill us or our pets, Kaufman said, such as heartworm.

Under the tenets of Integrated Pest Management, researchers work to keep pesticides viable as long as possible by encouraging people not to overuse them, and to employ other techniques instead.

That means carefully monitoring one’s dog for any sign of ticks, shampooing the dog and physically removing ticks before they gain a foothold, vacuuming frequently and ensuring that hedges and underbrush where ticks can hide are kept cut back.

While the brown dog tick isn’t a major disease threat to humans, it falls into the same “creepy crawly” category as bedbugs or fleas, said Faith Oi, an assistant extension scientist with UF’s entomology and nematology department.

“They’re bloodsucking insects,” she said. “It’s a difficult problem once the populations get high because they’re very good at getting into cracks and crevices. If you know where to treat, that’s one thing, but if you don’t even know where they are, it gets more difficult, and then you have to keep going back and back and it’s a very long process to get a handle on.”

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.