Investigators at the Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) at UConn recently reported a new canine disease, identified for the first time in New England. This is the same group, same laboratory, that recently reported eastern equine encephalomyelitis in horses and birds and earlier recognized epizootic hemorrhagic disease in deer (September 2017) and West Nile encephalitis in crows (2001).
The published case report (Journal of Veterinary Diagnostic Investigation, September 2019) documents the death of a 5-month-old dog that originated in Mississippi, was shelter-housed in Texas for a time, and then was delivered for adoption in Connecticut. The disease was characterized by severe bloody gastroenteritis and rapid progression to death. Autopsy was followed by electron microscopy and molecular techniques which demonstrated a circovirus as the cause of disease and death. First recognized in California in 2013, the appearance of canine circovirus disease in New England, in dogs shuttled among shelters, raises concerns for dog owners and veterinarians. At this time, it is hard to know if this disease will spread, like parvovirus disease in the 1980s, or remain sporadic.
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. Researchers and veterinarians UConn’s Connecticut Veterinary Medical Diagnostic Laboratory (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.
Pet owners, livestock owners, and outdoor enthusiasts statewide need to maintain vigilance against ticks because as the fall season approaches will see an increase in their activity. UConn’s Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL), part of the Department of Pathobiology & Veterinary Science in the College of Agriculture, Health and Natural Resources, is on the frontline of tick testing to inform submitters of the risks associated with that tick.
Ticks are disease-carrying arachnids that reside in moist areas, such as 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 the agent that causes Lyme disease (the corkscrew-shaped bacterium, Borrelia burgdorferi), it can also carry other disease-causing agents. A single tick can transmit more than one infectious agent.
“Our lab offers tick identification services, in addition to many other services,” says Dr. Joan Smyth, Director of CVMDL. 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, and to monitor for the spread of ticks that may have been recently introduced to our area, for example the long-horned tick. 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 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 three to five 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.