Anthrax: Is your pet
or farm dog at risk?

WHETHER we like it or not, the world is experiencing a resurgence in anthrax - a disease primarily of herbivorous animals. Human infections can be fatal and the slightest suspicion of anthrax contamination feeds our fears in a new world of terrorism and biological warfare. Around the globe anthrax spores are being detected amidst a flurry of hoaxes. Nowhere is this more apparent than in the United States of America. With a rising tide of anthrax hysteria placing limitations on our daily lives, we may be forgiven if we have not stopped to consider the impact anthrax may have on our pets.

Reports of anthrax occurrence in dogs scavenging infected carcasses are not entirely uncommon. Outbreaks in livestock and wildlife are encountered globally and the annual count for human anthrax is typically between 2000 and 3000, the majority of cases being reported from developing countries.

The World Health Organization has reported that countries with a low incidence, or that have become free of anthrax, usually have a larger number of infected animals when an outbreak does occur. This is mainly due to decreasing veterinary experience in recognizing cases and in dealing appropriately with outbreaks.

Canine outbreaks generally result from consumption of contaminated foods. Carcasses pose the most hazards in endemic regions and spores can live in the soil for many years. Anthrax is still common in European countries adjoining the Mediterranean (Greece, Italy, Spain, Turkey and Yugoslavia). In Canada anthrax persists in bison in the MacKenzie Bison Range, North West Territory, and Northern Alberta. Infrequent and sporadic incidences occur in southern Alberta and Saskatchewan. In the USA naturally occurring anthrax is confined to South Dakota, Nebraska and Oklahoma and is thought to persist throughout the south western quadrant of Texas.

Terrorist activities in the USA have undoubtedly changed this distribution as anthrax spores are detected within urban populations. A small risk to animals has been created within the city limits of those cities affected by bio-terrorism. Prior to such deliberate acts, anthrax was typically a disease of wild or farm animals in only a few isolated regions in the developed world. Anthrax is often endemic in developing countries. South America, Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East all report more anthrax in animals than other regions of the world.

Symptoms of anthrax disease vary between species, most veterinarians being familiar with the livestock indicators such as high fever, bleeding from the body openings, disinterest in feed, and quick onset. But a dog with anthrax will rarely show the same indicators as ruminant animals.

Canine anthrax typically has a slower onset becoming chronic. Most commonly, canine anthrax is limited to gastroenteritis and pharyngeal edema - a swelling of the neck and throat that can lead to asphyxiation. The organism enters tissue from the upper part of the digestive tract, probably through the tonsils. The intestinal form causes severe diarrhoea. As horrific as the above symptoms may seem, many dogs appear to have a natural resistance to anthrax and remain unaffected after ingesting spores from carcasses. Of course, in no way does this imply that it is safe to let dogs eat infected meat or carcasses. Dogs are tolerant of a larger number of spores, more so than most other mammals.

However, if your dog inhales or ingests enough anthrax, the result may be fatal to your pet and pose a significant risk to you personally.

Diagnosis usually involves an examination of the history and onset of the symptoms, isolation of Bacillus anthracis in the blood, and post-mortem if the dog has died. Sporulation is rapid on exposure to oxygen in the air but is almost eliminated if the carcass is not opened. In some countries it is illegal to perform post-mortem on animals that are anthrax suspects.

Antibiotics may be prescribed and must be administered early in the course of the disease to be effective. Treatment with antibiotics may remove the bacteria from its blood and tissues, but if sufficient toxin has been released by the organism then the disease may still have a fatal outcome for your pet. Vaccines for animals are available. Unfortunately the vaccine is not licensed for use in pets and if used some recipients may become very ill. As responsible pet owners we need to protect our dogs against anthrax. The best way to do this is to prevent your dog from eating any dead animal that has died of unknown causes. Wild animals in the suburbs and parks may become contaminated in their scavenging for food. Provide a fenced yard for your dog to live in and do not allow your pet to run loose as they may find a dead animal in their wanderings.

This has always been the advice to rural dog owners but now the same precautions must apply to dog owners within the suburbs and cities globally. Follow your government's regulations for pet ownership as these rules ultimately protect you and your dog from hazardous disease and serve to contain outbreaks when these do occur.

If your pet is displaying symptoms typical of anthrax disease then contact your veterinarian immediately. Any delay may diminish its chances for survival. The veterinarian may wish to examine the animal at your residence to prevent exposure of anthrax spores to other pets, persons, or the environment.

If your vet suspects anthrax, it would be wise to seek medical advice for your family just as a precaution. Anthrax can be transmitted to people from animal hair. With much of the world cautiously on alert looking for the next case of anthrax, it is easy to put any potential risk well out of proportion. With customs and drug dogs being the exception, any risks to your pet at the time of writing are only slightly raised and it is unlikely that your pet will encounter this disease. However, the extent that spores have contaminated our environment is as yet unknown and it may be some time before the full impact of recent events is realised. - K Scott