College of Veterinary Medicine Research Brochure

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Mycoplasmas Play Key Role in Disease of Humans, AnimalsIIt’s no wonder that pathobiologistMary Brown is one of the topfundedresearchers in the University ofFlorida’s College of Veterinary Medicine.Her specialty – microscopic organismscalled mycoplasmas – show up justabout everywhere.Over the past 20 years, Brown hasstudied infections in creatures fromalligators to humans. She has studiedthe role of mycoplasma in the prematurebirth of babies and in a respiratoryailment of tortoises. Mycoplasmas areat work in urinary tract infections inwomen and in economically importantdiseases of dairy calves.Mycoplasmas are busy, and they keepBrown busy, too.“Only a few hundred of usworldwide work on thesemicrobes,” Brown said. “We try toadvance the basic science, and Ialways find there are so manyquestions to ask but so little time.”Mycoplasmas are the smallest freelivingbacteria. They need intimatecontact with a host, for instance inthe respiratory or urogenital tract,and establish a chronic disease thatusually is not fatal because theyneed the host in order to survive.The bacteria spread through directcontact, and “walking pneumonia” isone example of a mycoplasmaldisease in people. Few could lovemycoplasmas, but they have yieldeda lifetime of research for Brown.“There are so many interesting hostsin veterinary medicine,encompassing animal and humanhealth as well as conservationissues,” Brown said. “With thisresearch we can not only help theanimals but help humans, too.”Most recently, Brown has beenstudying the role of mycoplasmasin a respiratory infection that hasspread rapidly among Florida gophertortoises, a species of special concern.The gopher tortoise population hasdeclined in part because of loss ofhabitat. The habitat loss also meansgopher tortoises live in closerproximity to each other, a conditionthat likely allows infections to spreadmore easily.Well-meaning citizens havecompounded the problem, Brownsaid. In one study site in DuvalCounty, people were releasingtortoises displaced by developmentof a subdivision. The newcomertortoises were sick withrespiratory mycoplasmosis, whichswept quickly through the existinggopher tortoise population.“This was a prime example of whathappens when an acute diseasecomes through a population,”Brown said. “We are seeing verysick animals and increased deaths.Some females also appear not to beproducing eggs. Loss ofreproductive-age adults, decreasedreproductive rates and the lowsurvival rate of young tortoisehatchlings combine to make it veryhard for a tortoise population torecover from a population crash.”Brown and her team worked withregulatory agencies, state parks andwater management districts to do astatewide survey of habitat statusand changes in the gopher tortoisepopulation. She and the team alsodeveloped a diagnostic test for thepresence of mycoplasma.Her work with the threatened speciesattracted a $2.2 million grant fromthe National Science Foundation tosupport further investigation.“We’re just beginning to understandthe diseases in wildlife that arecaused by mycoplasma,” Brown said.“It’s a very adaptive organism.”On the human side, women stand tobenefit from Brown’s research.Mycoplasma can take up residencein the urogenital tract, causing avariety of problems.Brown has been awarded a NationalInstitutes of Health grant to studythe role of mycoplasma in recurrenturinary tract infections in women.Her research is centered on findingthe factors that dispose somewomen to recurrent infections asopposed to one-time infection andwhether mycoplasma plays a role inan exaggerated inflammatoryresponse to an infection. She is alsostudying whether there are geneticfactors in a woman’s susceptibilityto urinary infections.Women also could gain from a studyon mycoplasma infections in thegenital tract and their role inpregnancy loss and premature birth.In that study, Brown is questioningwhether loss of pregnancy is thebody’s response to the infection. Hereventual goal is to develop a methodto screen women for pregnancy loss.In the meantime, she is working onan animal model using rats infectedwith mycoplasma.“Once we establish the model, wecan ask and answer a lot ofquestions,” Brown said. “Somestrains of rats are moresusceptible to adverse pregnancyoutcome, so we will look intowhich genes are turned on in theplacenta of those rats and whenthey are turned on and turned off.”“The data would help humansand animals, and that makes it awin-win,” Brown said.The U.S. Department ofAgriculture has funded yetanother study of mycoplasmaldisease in food and fiber animals.In dairy cows, for instance, thebacteria cause mastitis. In youngcalves, a mycoplasmal infection canlead to severe disease and sometimeseven death, and is an important herdcost for dairy farmers.“There are as many differentspecies of mycoplasma as there arehosts,” Brown said. “All theseprojects require large teams, a realteam approach. Science is not donein a vacuum.”Brown likes to share her success atgetting grants by helping graduatestudents and other youngresearchers obtain grants of theirown. For her, that’s as rewarding asthe basic science.“When I watch the development ofthese young scientists,” Brown said,“I can’t imagine having a better job.”Photo left: Dr. Mary Brown, shown with scientistDr. Lori Wendland, has been studying the roleof mycoplasmas in a respiratory infectionthat has spread rapidly among Florida gophertortoises, a species of special concern.30Research • University of Florida College of Veterinary Medicine••Environment • www.vetmed.ufl.edu31
Advancing Health of Wildlife, Endangered SpeciesHHe is the go-to guy forpeople who want to helpailing reptiles, including endangeredturtles at sea and tortoises on land.The plight of these mild-manneredcreatures has taken Universityof Florida wildlife and zoologicalmedicine Professor Elliott Jacobsonfrom the Florida Keys to theMojave Desert.Jacobson has seen sea turtleswith fibropapillomatosis –grotesque tumors that are benignin themselves but kill when theycover the eyes or mouth or interferewith the motion of flippers.In tortoises, both in the MojaveDesert and Florida, he has studieddeadly respiratory ailments thatcan spread quickly.Unlike veterinarians who treatbetter-known domestic animals,wildlife veterinarians often havelittle of even the most basicinformation, and that is whereJacobson’s work begins.“For many wildlife species we don’thave reference values,” Jacobsonsaid. “So we need to establish anormal database in order todetermine what is not normal forthese animals.“We’re in the process of building adatabase on blood values for seaturtles in Florida and around theworld, so we will know what’s intheir blood, the biochemicalcomponents of their blood,” saidJacobson, who is collaborating onthe project with the Archie CarrCenter for Sea Turtle Research andthe St. Lucie Power Plant. “Thiswill become more and moreimportant as we try to help theseanimals survive.”Jacobson and his colleagues beganworking on fibropapillomatosis insea turtles in the mid-1980s whenturtles with the bizarre growthsbegan showing up at a hospital inMarathon. A single turtle can havemore than 50 lesions, some as largeas 12 inches across, on both softbody tissue and the shell. Sea turtlesare endangered and reproduceslowly, so a disease likefibropapillomatosis, which affectsmore than 50 percent of some turtlepopulations, can be devastating.Jacobson and a graduate studentdiscovered herpes virus in thetumors. The student is now thehead of Laboratory Animal Medicineat Albert Einstein College ofMedicine in New York and isinvestigating a link between thevirus and the tumors.More recently, Jacobson hasbegun work on ways to improvediagnosis of maladies in wildlife. InNovember, he published the resultsof a study of the usefulness ofmagnetic resonance imaging andradiography in determining thepresence of internal fibropapillomasin sea turtles.At the turtle hospital in Marathon,veterinarians have been able toremove the exterior tumors from seaturtles and return them to theocean. However, the possibilityexisted that the animals would goon to suffer and die from internaltumors. Most turtles with internaltumors need to be euthanizedbecause the tumors interfere withthe operation of organs and severelydamage surrounding tissue.Jacobson’s study foundradiography’s benefits limitedbecause internal views weresomewhat obscured by the shell.However, MRI scans were notaffected by the shell andprovided detailed views of theturtle’s organs and internal tissue,easily revealing the presence orabsence of the tumors.There are both practical andemotional reasons to do this work,Jacobson said.“Sea turtles are important to Florida.We have the largest nesting beachesin the United States and more deadturtles wash up here thanelsewhere,” Jacobson said. “It’s afederally listed, charismatic animal.You see a sea turtle laying eggs andpeople are fascinated by them. Theyare benign, long-lived animals.”Jacobson and a graduate studentalso have begun work on anotherproblem plaguing sea turtles.Somewhere on their round-tripbetween Florida and theMediterranean, the animals arepicking up deadly parasites.“Sea turtles have the most uniquemigration pattern of any animalon the planet,” Jacobson said.“They travel from here to theMediterranean and back, andsometimes it takes 10 to 20 yearsto complete that migration. Theseparasites don’t exist in the CanaryIslands, so that’s an important partof this puzzle. They’re picking themup when they come back.”Necropsies have shown clustersof parasites in the brain, butJacobson and veterinary pathologistBrian Stacy are just beginningresearch to find out where theparasites come from.On land, Jacobson’s work withtortoises began in 1989 with anurgent call from a Californiapreservation group worried about astrange upper respiratory tractdisease that was causing a die-off oftortoises in the Mojave Desert.Jacobson put together a researchteam that discovered a microbeknown as mycoplasma wasresponsible for the infections.Soon after, the problem cropped upcloser to home when Florida gophertortoises began contracting therespiratory ailment. The researchused in the desert tortoise studieswas applied to the gopher tortoisesand the presence of the mycoplasmawas detected.While scientists continue to studythe disease in tortoises, which arespecies of concern due to sharpdeclines in their populations,Jacobson says some common senseguidelines would help controlspread of the disease. For example,in high-growth areas it is commonfor well-meaning people to relocatethe displaced animals to anotherwild area. What they don’t realize,Jacobson said, is that they may berelocating a sick animal andspreading the disease.With 260 species of turtles andtortoises, most in decline, moreresearch and collaboration isneeded, Jacboson said.“We’re seeing an extreme loss oftortoises and habitat,” Jacobsonsaid. “As populations dwindle, thosepopulations will need to be moreintensely managed. One of the mostimportant outcomes of our work isto bring attention to these issuesand educate people.”Photo left: Dr. Elliott Jacobson shownwith a sea turtle that received rehabilitationafter being drawn into a canal near thePort St. Lucie Power Plant. Jacobson workswith many sea turtles, snakes and otherreptiles both clinically and in his research.32Research • University of Florida College of Veterinary Medicine••Environment • www.vetmed.ufl.edu33
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