Rabies Immunity

For decades, rabies has been viewed as a 100% fatal disease. A new study released today has not only shown that that is an inaccurate statement, but that some people may have a natural immunity. The study, conducted in an isolated group of Peruvian natives in the Amazon, showed that almost 10% of those who were exposed to the virus never got sick.

In the Amazon, there is a plethora of vampire bats, which normally feed on livestock, but when there are no animals around to feed on they pray on sleeping humans. It is not uncommon for natives to have interactions with these bats, and many may even sleep through the whole situation. It is believed that the constant exposure to these bats is what has begun to build antibodies and a certain level of immunity in the natives.

Blood samples were taken from 63 of the 92 participants in the study. Out of those 63 participants, 11% of them had a natural immunity to rabies. 50 of the participants were able to confirm that they had previously been bitten by a bat. One of the seven (11%) in the group had previously been vaccinated for rabies, so the new focus is on the 6 who have never had a vaccination and had not sought medical care after a bite. The new questions for researchers – How did they build this immunity?

While more thorough research is needed to conclusively determine if the antibodies were built from a weaker form of the rabies disease, it is suggested that rabies may not be fatal to every human on the planet. Once a new study is able to determine how this has occurred and what is making it occur, there could be potential for a new vaccine or treatment that may save more lives.

Rabies kills nearly 55,000 people a year worldwide, with the highest case numbers coming from Africa and Asia. In the United States, while there has been a slight outbreak due to our light winter (reported in our previous rabies post), we have almost eradicated the disease thanks to our domestic animal vaccinations. Researchers agree that patients who show clinical symptoms of the disease will endure a fatal case, but there are many who never exhibit symptoms and avoid medical treatment post exposure.

The one thing to keep in mind is that while rabies usually presents sooner rather than later, it can incubate in the body for lengthy periods of time. This will no doubt play part in further study, and could explain why some never gets sick from the virus, if they are simply able to remain carriers. In any event, it is an interesting change in how this disease is looked at, with the potential for a positive outcome.

Sources: US News/HealthDay http://health.usnews.com/health-news/news/articles/2012/08/01/untreated-rabies-may-not-be-lethal-for-all-study-says LiveScience http://www.livescience.com/22044-vampire-bat-bites-rabies-immunity.html Daily Mail UK http://www.dailymail.co.uk/sciencetech/article-2182589/Potential-new-vaccine-rabies-bad-news-youll-need-bitten-vampire-bat.html?ito=feeds-newsxml