When you live in a country such as the United States, where vaccination of dogs and cats is common, at least in your neighborhood, it can be easy to forget that there’s a reason why we vaccinate. The core vaccines we provide to our pets were invented in response to specific fatal outbreaks and epidemics that have killed many animals but that are much less frequent now due to our widespread vaccination programs. One can be reminded of the negative effects of non-vaccination by looking at shelters statistics or by visiting a developing country.

Says Janice Girardi, founder and director of the Bali Animal Welfare Association serving Bali, one of the islands that is part of the 17000 island archipelago that forms Indonesia, “We see distemper and parvovirus infection a lot. It’s our biggest problem. It goes in waves. We are in an upwave with distemper right now and for instance, just euthanized two affected puppies yesterday for distemper.”

She continues, “We have to buy test kits and if we see any dogs with symptoms test them and euthanize them if they are positive. We cannot treat sick animal successfully.”

Parvovirus, the intestinal virus that causes diarrhea, dehydration, and ultimately shuts the dog’s system down is common too. While puppies in the U.S. are treated aggressively and have a good chance of survival, in Bali, where treatment is bare bones, the recovery rate is low. Even worse, the virus can survive for a year in the ground.

Overall, distemper and parvovirus infections are status quo in developing nations, but the infectious disease that is oft forgotten causing the most problems right now is rabies. Today on World Rabies Day, which occurs on September 28 of each year, it’s a good time to remember the importance of vaccinating for rabies too.

Worldwide rabies kills roughly 55,000 people per year, mostly in developing countries where few animals are vaccinated.  Because of the lack of vaccination, a single animal with rabies can cause an outbreak. For instance, in 2008 Bali, which had been rabies free, reported its first case of human rabies. The virus, which is most frequently transmitted by bites from infected dogs, gradually spread throughout Bali and in just under three years, 130 people have been died. This scenario is not that uncommon. China reported an outbreak in 2006, 2009, and again this year, and in 2009 a rabies outbreak in Luanda, the capital of Angola, lead to the death of 93 children within 3 months.

Many developing countries with low funds for healthcare resort to trying to rid the country or area of dogs. According to Francois-Xavier Meslin, leader of the World Health Organization’s Neglected Zoonotic Diseases team in Geneva, “The problem is that killing dogs, the favored method for dealing with rabies in much of the developing world, simply creates a “vacuum effect” whereby infected dogs move into the areas where culling has occurred.”

What works better is vaccinating a large enough portion of the population, generally 70%–80%.  By vaccinating this large percentage, the population of dogs develop what’s called herd immunity. That is the population develops a level of resistance that is sufficient to prevent the reintroduction of the virus from causing an outbreak. While individual dogs may be sporadically infected by the disease, the number of dogs with disease remains low. Additionally, vaccinated females produce maternal antibody which helps protect their puppies during the first couple of months while their immune system is developing.

The moral of the story for us in the United States, is that if your dog remains unvaccinated against rabies, or parvovirus or distemper and he does not get disease it doesn’t mean that the practice of non vaccination is safe. It means he’s just lucky that he lives in a country where the level of virus is relatively low because many other dogs are vaccinated. But if he finds himself in a shelter situation or other location with a high number of unvaccinated dogs and a dog comes in with infectious disease, that disease may spread quickly, producing huge amounts of virus in the environment, meaning a higher likelihood for each dog to get sick and a high likelihood of outbreak. For proof, just search the web for examples of such outbreaks covered in the news.

Even worse, if the rest of the population follows your lead and decides they will never vaccinate their pets, eventually your community’s herd immunity towards that disease will decrease. If that were to happen, then we in the U.S. could experience what developing regions such as Bali, or Angola, or China experience every day.

For other articles on this subject, read these on Huffington Post and Victoria Stilwell’s Positively.com blog.  

Have you had a pet get a disease that could have been vaccinated against?  Share your story here.