CANINE DISTEMPER
ByThe American Veterinary Medical Association
Canine distemper is a highly contagious and serious disease caused by a virus that attacks the respiratory, gastrointestinal, and, often, the nervous systems of puppies and dogs. They usually become infected through airborne exposure to the virus contained in respiratory secretions of an infected dog or wild animal. Outbreaks of distemper tend to be sporadic. Because canine distemper also affects wildlife populations, contact between wild canids and domestic dogs may facilitate spread of the virus.
All dogs are at risk but puppies younger than four months old and dogs that have not been vaccinated against canine distemper are at increased risk of acquiring the disease. The first sign of distemper is eye discharge that may appear watery to pus-like. Subsequently, dogs develop fever, nasal discharge, coughing, lethargy, reduced appetite, vomiting, and diarrhea. In later stages, the virus may attack the nervous system, bringing about seizures, twitching, or partial or complete paralysis. Occasionally, the virus may cause footpads to harden. Distemper is often fatal. Even if a dog does not die from the disease, canine distemper virus can cause irreparable damage to a dog’s nervous system. Distemper is so serious and the signs so varied that any sick dog should be taken to a veterinarian for an examination and diagnosis.
Veterinarians diagnose canine distemper on the basis of clinical appearance and laboratory tests. No specific drug is available that will kill the virus in infected dogs. Treatment consists primarily of efforts to prevent secondary infections; control vomiting, diarrhea, or neurologic symptoms; and combat dehydration through administration of fluids. Sick dogs should be kept warm, receive good nursing care, and be separated from other dogs.
Vaccinations and avoiding contact with infected animals are key elements of canine distemper prevention. Young puppies are very susceptible to infection because the natural immunity provided in their mothers’ milk may wear off before the puppies’ own immune systems are mature enough to fight off infection. If a puppy is exposed to canine distemper virus during this gap in protection, it may become ill. Ann additional concern is that immunity provided by a mother’s mild may interfere with an effective response to vaccination. This means even vaccinated puppies may occasionally succumb to distemper. To narrow gaps in protection and optimally defend against canine distemper during the first few months of life, a series of vaccinations is administered.
Until a puppy has received its complete series of vaccinations, pet owners should use caution when taking their pet to places where young puppies congregate (pet shops, parks, puppy classes, obedience classes, doggy daycare, and grooming establishments). Reputable establishments and training programs reduce exposure risk by requiring vaccinations, health examinations, good hygiene, and isolation of ill puppies and dogs. To protect their adult dogs, pet owners should be sure that their dog’s distemper vaccination is up-to-date.
EXPERTS CAUTION AGAINST LYME DISEASE
By Alana Melanson
Though the tick season may have started earlier due to the mild winter the region has experienced, it does not necessarily mean there will be more ticks later on, experts say. According to Dr. SamTelford, a professor of infectious diseases atTuftsUniversity’s Cummings School of Veterinary Medicine in Grafton, there is no surefire way to predict the cycles of tick populations. Telfordhas been studying Lyme disease and other tick-borne illnesses since 1984, and says there is still no predictive model that observations could be plugged into to determine how future seasons will go, despite predictions some are making that this season will be particularly bad in terms of a larger tick population and more cases of Lyme disease.
Telfordsaid the fall of 2010 was a particularly bad time for ticks because of a number of environmental factors that came into play. For instance, oak trees produced more acorns, meaning squirrels, mice and other rodents were plentiful and able to survive longer through the cold weather, he said, acting as hosts for the ticks and spreading them wherever they scurried. The amount of moisture available in the environment plays a role as well, he said. “Ticks require very high humidity to survive for a long time,”Telfordsaid. “That’s why we don’t see ticks on well-groomed lawns.” With the sun beating down and nowhere for the ticks to hide,Telfordexplained, they can’t survive for long in those hot, dry conditions and will often take shelter where there is more vegetation.
Someone would have to spend four hours in the center of a lawn, or 20 minutes at the edge of a yard bordering a forest, to be exposed to the same amount of ticks one could pick up from five minutes in the deep woods, he said. Telfordsaid there are likely to be about 10 times fewer ticks present from noon to 4 p.m., as that is when daytime temperatures usually reach their peak and when it tends to be least humid.
If May and June are dry, he said, there could be relatively fewer ticks than normal at that time of year. But because no one can accurately predict the long-term course ofNew Englandweather, he said it is best to practice good sense when it comes to traversing through wooded areas. A large deer population also affects whether there will be a boom in deer ticks,Telfordsaid, and deer are staying closer and closer to suburban areas as development takes over their woodland homes. Retaining a proximity to houses and settled areas also means the deer are less likely to be hunted in those areas, he said.
According toTomO’Shea, assistant director of wildlife for Mass Wildlife,Fitchburgand its environs tend to be around the state’s deer-density goal of 12 deer per square mile, but east of the area, deer densities are significantly higher. Some communities further east have experienced a surge in Lyme disease, and as a result have allowed hunting on municipal properties to bring the deer population down, O’Shea said.
Although ticks can pose quite a problem, that shouldn’t stop people from enjoying walks in the forest,Telfordsaid, adding that they should simply be more vigilant and take proper precautions. Wear long sleeves and tuck long pants into socks, he said, and spray ankles and shoes with bug repellent. Although most strong repellents with DEETwill work, he recommends permethrin, a chemical used in military uniforms that causes ticks and mosquitoes to die within a few hours of exposure. It is also the active ingredient in most head-lice shampoos, he said. “What’s even more helpful is to take a shower after walks in the woods,”Telfordsaid, explaining that running water is likely to remove any ticks that have not implanted themselves. He recommended checking one’s own body for new bumps as well as having a partner check areas that are difficult to see.
If bitten by a tick, it generally takes an attached tick about 24 hours to transmit Lyme disease and other tick-carried illnesses,Telfordsaid. Only Lyme may boast a bull’s-eye rash, but all will produce flu-like symptoms, including fever and muscle aches, he said, so if those are present, it is best to see a doctor. If one is worried and does not want to wait until symptoms are exhibited, most doctors will prescribe a single dose of the antibiotic doxycycline to try to prevent an infection, he said.
If possible, Telfordrecommends taping the tick to an index card and writing the date on it, to show to a doctor later should symptoms arise. Several online resources for identifying types of ticks and other insects are available as well, he said, including www.identifyus.com, a site run by colleagues of his. In addition to Lyme disease, consideration must also be taken for Babesiosis and Ehrlichiosis (also called anaplasmosis),Telford said, similar bacterial infections that ticks in this area are known to carry, though to a much smaller extent.
The vast majority of people with Babesiosis exhibit no symptoms and may go their entire lives without knowing they are infected, provided they remain in good health,Telfordsaid. Only in cases of those with suppressed immune systems or those who lose their spleens due to accidents can the infection become fatal, he said. The problem that is beginning to arise, however, is that Babesiosis-infected people may donate blood and pass the infection along to those who may not be able to fight it,Telfordsaid, as it is not among screened-for diseases.
While a Lyme disease vaccine exists for canines, there is not one available for humans,Telfordsaid. Though SmithKline (now GlaxoSmith-Kline) developed one previously, he said, the company stopped offering it because it was losing money on the product in a time when Lyme disease wasn’t as big a problem as it has become. As there is no way to ensure zero risk of Lyme disease and other tick-borne illnesses,Telford said exercising caution, for both humans and animals, is the best way to reduce risk.
Though people tend to think of the winter months as a safe time from ticks, local veterinarians say it is best to keep pets protected year-round. “We see ticks on dogs and cats every month of the year,” Dr. Carl Flinkstrom of the Lunenburg Veterinary Hospital said. “One out of seven dogs that walk in this door test positive for Lyme disease.” At Twin City Animal Hospital in Fitchburg, Dr. Terra Baldarelli said about one in four dogs tests positive. “We live in an endemic area,” she said. “It’s extremely common here. But it doesn’t mean that they all get sick.” Only about 5 percent or less of the dogs actually come down with symptoms, she said, but those that test positive do get treated to ensure they do not become sick later.