Connecticut Veterinary Medical Diagnostic Laboratory

Equine Owners Should Vaccinate for EEE, Warns CVMDL at UConn

Eastern equine encephalitis slide
Colourised transmission electron micrograph (TEM) depicting a salivary gland that had been extracted from a mosquito, which was infected by the Eastern equine encephalitis (EEE) virus, which has been colorized red; magnified 83,900x. {{PD-USGov-HHS-CDC}}

Eastern Equine Encephalitis (EEE) is a disease caused by a virus that mosquitos transmit. The name of the disease is misleading in that this virus can infect and cause disease in humans and a wide variety of animal species, including birds as well as horses and other equids. Horses that have not been vaccinated for EEE die within days of being infected as there is no treatment. There is an effective equine vaccine for EEE, however not for other species. In recent weeks. two unrelated sick birds, one of which was a bald eagle, tested positive for EEE at UConn’s Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL). Researchers and veterinarians at CVMDL encourage equine owners to consider vaccinating their animals, and other animal owners to implement measures to reduce mosquito habitats and thereby potential contact with mosquitos.

Mosquitos that feed on infected wild birds transmit EEE to horses and humans. Once infected, the virus attacks the central nervous system of the host. For horses, disease signs usually appear within five days and the clinical signs include fever, a dull or sleepy appearance, muscle twitches, and a weak staggering gait. Fatality in horses is 90% or higher as horses often go down and are unable to stand again, and those that do survive may have permanent brain damage.

EEE is transmitted by two main types of mosquito vectors; the primary vector and the bridging vector. Culiseta melanura, the primary vector which feeds almost exclusively on birds, serves to amplify and maintain the virus within wild bird populations. Other mosquito species, which indiscriminatingly feed on birds, horses, and humans, serve as the bridging vector capable of transmitting EEE from wildlife to horses and humans.

With the location of horse barns and pastures in rural areas the animals have increased exposure to mosquitos. Horses cannot pass EEE to humans, or to other horses, and are therefore referred to as a dead-end host. If an infected mosquito bites a human, that person can be infected and may develop disease. According to the Center for Disease Control, illness in humans due to EEE is rare, but when disease develops, it is serious.

Proactive steps can be taken to prevent EEE virus infection in humans and horses. A vaccine is available for horses, talk to your veterinarian about vaccinating annually for EEE. Mosquito control techniques include eliminating standing water, cleaning water troughs weekly, avoiding mosquito-infested areas, and using insect repellent.

CVMDL, part of the Department of Pathobiology in UConn’s College of Agriculture, Health and Natural Resources, is on the frontlines of research and testing to keep humans and animals safe. For more information visit http://cvmdl.uconn.eduor call 860-486-3738.

References:

LSU Ag Center Research and Extension: http://www.lmca.us/PDF/pub2834eee.pdf

UConn CVMDL Monitoring for Longhorned Tick

A female longhorned tick (Haemaphysalis longicornis). Credit/ James Gathany/CDC/Anna E. Perea2018
A female longhorned tick (Haemaphysalis longicornis). Credit: James Gathany/CDC/Anna E. Perea 2018

Recent reports of the longhorned tick (Haemaphysalis longicornis or Asian Longhorned tick)being found in Westchester County, New York have alarmed livestock owners and outdoor enthusiasts statewide. The longhorned tick is native to Asia and was reported in the continental USA in November 2017, when it was first discovered on a sheep farm in Hunterdon County, New Jersey.  This tick has already been identified in western Connecticut.  While the Asian longhorned ticks discovered in the United States has not been found to carry any pathogen causing human diseases, In Asia the longhorned tick has been associated with tick-borne encephalitis, and they are apparently capable of carrying Anaplasma phagocytophilum, Ehrlichia chaffeensis, Babesiaspecies, and Powassan virus all of which can affect humans. This tick may also represent a problem for farm animals since they can transmit a pathogen that causes theileriosis, a disease of cattle and sheep, as well as the agents that cause babesisosis in animals. An interesting feature of this tick is that it can reproduce by parthogenesis (no male needed), so the number of ticks on one animal can be very high.

UConn’s Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL), part of the Department of Pathobiology in the College of Agriculture, Health and Natural Resources, is on the frontline of tick testing to keep humans and animals safe.

“Our staff are watching out for this tick among our tick submissions,” says Dr. Joan Smyth, Director of CVMDL. “To date we have not had any longhorned ticks. Our lab offers tick identification services, in addition to the many other services provided.”

Ticks are disease-carrying arachnids that reside in moist areas, long grass and the leaf litter and will latch onto humans and animals alike. Although there are many different species of ticks, people generally think of one tick species in particular when worrying about illness: the deer tick (Ixodes scapularis). While the Deer tick is predominantly known for transmitting Lyme disease (caused by the corkscrew-shaped bacterium, Borrelia burgdorferi) it can also carry other disease-causing agents. A single tick can transmit more than one infectious agent.

In humans, symptoms from a longhorned tick bite include rash, fever, nausea, body aches, tiredness, headache and vomiting. Symptoms for animals vary by species and can include blood loss, anemia, skin irritations and infections. Always consult your veterinarian if you notice changes in your animals.

Tick testing at CVMDL serves multiple purposes. It helps the person or veterinarian who submitted the tick understand the potential exposure of the subject that the tick was found on. Our researchers are also using the results from tick testing to track current and emerging disease producing agents carried by ticks. The data can be used in setting priority areas for prevention and vaccine development.

If you find a tick on yourself, your child, or your pet, remove it immediately! CVMDL can test the tick for pathogens. Ticks received at the CVMDL are first examined under a microscope by trained technicians to determine the species of tick, life stage, and degree of blood engorgement, all of which are factors that may impact transmission of pathogens to the person or animal. Ticks may then be tested for the DNA of pathogens that are common to that tick species. Results are normally reported within 3-5 business days of receiving the sample, but next day testing is available for an additional fee.

Please send ticks together with a small square of moist paper towel, in sealed zip lock bags. The submission form, pricing and the “Do’s and Don’ts of tick testing” can be found on our website at http://s.uconn.edu/468.

For more information, read the article from UConn Magazinethat includes tips to prevent tick bites, or watch the UConn Science in Seconds video. You can also contact the Connecticut Veterinary Medical Diagnostic Laboratory at cvmdl@uconn.edu or 860-486-3738 or visit the tick testing page on our website http://cvmdl.uconn.edu/service/tick.php.

Bats and Rabies: How UConn May Help

The Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) within the Department of Pathobiology and Veterinary Science (PVS) in the College of Agriculture, Health and Natural Resources (CAHNR) at the University of Connecticut routinely tests domestic and wild animals for rabies. Rabies is one of the oldest recognized diseases to mankind. Rabies can affect all warm-blooded animals which plays an important role in transmission of the disease and serve as reservoirs for the rabies virus.

To detect rabies in animals, a set of strict standard operating procedures are followed. The CVMDL performs a Direct Immunofluorescent Assay (DFA) on brain tissue derived from dead animals. These animals, usually with a history of abnormal behavior, are submitted to the laboratory for testing.

The CVMDL tests many domestic and wild animal species on a weekly basis for rabies. Among them, bats are a fairly common submission to CVMDL for rabies testing. For instance, during 2016, a total of 28 bats were submitted to CVMDL, with the majority of the submissions taking place during the months of June, July and August. All of these bats tested negative for rabies.

graph of 2016 rabies tests in bats

Interestingly enough, in 2017, CVMDL has already tested 40 bats for rabies. The virus was detected in the brains of two bats that were submitted to the lab in July and October, respectively. Remember, always be cautious when dealing with wild animals. CVMDL suggests to call your local animal control to help collecting or trapping wild animals.

For more information, visit cvmdl.uconn.edu or contact 860-486-3738 or CVMDL@uconn.edu.