Are there more fleas, ticks and other pests? Have they developed resistance to spot-on and other protective treatments?
The answer to the first question is yes. As more people move to the suburbs wildlife and its population of fleas and ticks have greater access to our pets. Hunting and natural predation has a smaller impact so populations of deer and some other species are exploding. Changing climate and habitat brings both host species and parasitic vector species into new regions of the country, while new species are being introduced inadvertently from abroad, whether it is juvenile forms carried by migratory birds, or parasites hitching rides on international travelers or in products imported to this country. One such immigrant is the Asian tiger mosquito Aedes albopictus. Unlike native species of mosquitoes which do not feed during the day, this species does. Since it first appeared in the US in 1985 it has become widespread in the Eastern part of the country, and can now be found as far north as Maine.
Heartworm, Lyme disease, anaplasmosis and ehrlichiosis have been found in virtually all the states, although incidence still varies. Snap 3Dx and 4Dx test results from 3 million dogs between 2000 and 2008 for example found heartworm in 3.9% of dogs in the Southeast, 0.8% in the Midwest, 0.6% in the northeast and 1.2% in the west, an area where the disease was previously thought to be rare to non-existent. Nationwide 5% of dogs show exposure to Lyme disease, with the highest incidence in the Northeast. Meanwhile ehrlichiosis is most common in the South and anaplasmosis in the Midwest.
It is the increased prevalence of fleas, ticks and mosquitoes that lead many of us to conclude that the parasites have developed resistance to the spot on products such a Frontline, Advantage/Advantix and Revolution, when they are simply overwhelmed. We need to treat the environment as well as the animal.
What can you tell me about Babesia?
Babesia is protozoan parasite found in the blood that causes a hemolytic disease known as babesiosis. It has been receiving quite a bit of interest lately. It seems that Babesia spp are spreading into areas where they previously didn’t exist, but we also more aware of the organism and more likely to test for it. It has been discovered that there are at least 10 species of the parasite that are genetically unique. In the past, diagnosis was usually made by finding the parasite on a blood smear, but the newer panels used to test for tick borne diseases on a molecular level are far more likely to identify Babesia as a cause of disease. While Babesia is most common in the southeastern United States, it cannot be ruled out in other locations, ticks and dogs are on the move!
As well as being transmitted by ticks, babesiosis can be transmitted by blood transfusion, transplacentally and directly by bite wounds from an infected animal. The “vaccines” available against some forms of Babesia that are available in parts of Europe are not effective against the species found in the US. They also do not prevent infection just reduce the severity of clinical disease.
Any dog with thrombocytopenia (low platelets), regenerative anemia, elevated blood globulins and/or a fever that comes and goes should be tested for babesiosis. While babesiosis is most commonly found in pit bulls and greyhounds, a history of exposure to ticks, being bitten by a dog of one of those two breeds or having had a blood transfusion would increase the likelihood of babesiosis.
Treatment is based on species. B. canis is treated with imidocarb dipropionate, while for B. gibsoni a combination of atovaquone and azithromycin is used. Treating with prednisone tends to reduce the efficacy of these drugs. This is important because if you do not clear infection with B. gibsoni at the first attempt, it usually becomes resistant and the patient remains infected for life. Antibiotics such as doxycycline are ineffective against Babesia spp.
I’ve heard about a new strain of killer parvovirus (2c) what can you tell me?
Canine parvovirus 2c (CPV-2c), just like the older strains (2a and 2b), can cause the same range of clinical signs from mild to severe. While other strains are more likely to produce hemorrhagic diarrhea, CPV-2c often produces a yellowish diarrhea, which might reduce the veterinarian and owner’s suspicion that the dog has parvo. While CPV-2c has been reported in 15 states there is no reason to suspect it won’t eventually spread throughout the country. It was first reported in Italy and has been found elsewhere in Europe as well as in parts of Africa and South America. Unlike the other strains it may as likely be found in small as large breeds of dog. Like the other species it is primarily found in puppies though with the peak age being 2 months. Shipping puppies in poorly ventilated conditions with lowered immunity due to ill-health and disease will help spread infection. Good news is that according to Dr. Ron Schultz of the department of pathobiological sciences, University of Wisconsin School of Veterinary Medicine current vaccines for CPV are protective against CPV-2c, and provided the dog has received the vaccine after maternal antibodies have worn off, the vaccine should protect for life as it does against other strains. The CPV-2c variant is also detected by the Idexx Snap Parvo test making for rapid diagnosis if a dog is infected. Treatment – as for other variants – is isolation and supportive care to replace electrolytes lost through vomiting and diarrhea. This is a very stable and hardy virus that can live a long time in the environment, so disinfection is critical to prevent it recurring in other animals kept in the same environment.
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