Cows, Drugs, Vultures, Bats and Rabies

They have just worked out that a mass accidental poisoning of vultures in India has indirectly killed 50,000 people in a horrible manner.

You see the vultures were eating the dead cows. Often before the cows died, and routinely while they were alive, they were given a drug called Diclofenac (also known as Voltarol) which is a pain kller. Good for cows (and people) but it causes kidney failure in vultures. They have died in the millions in India. A terrible conservation disaster...

But next level of unforeseen disaster has only just come to light. There has been a big jump in the number of people dieing of rabies and almost 50,000 have died. How come?

Well, without the vultures to compete with the feral dogs numbers have boomed - and the dogs are a very efficient vector for rabies - more feral dogs = more feral dogs with rabies = more people bitten by rabid dogs = more deaths from rabies. Here is the article in the New Scientist about it...

There is a similar disaster concerning rabies and cows unfolding in the Venezuelan jungle where 38 members of the isolated Warao tribe are sucoming to a fatal mystery disease. Many doctors believe this too is rabies, but this time carried by vampire bats (how about that for a theme for a horror movie?). Again from the New Scientist

There have been vampire bats, rabid vampire bats, and people in the South American jungle since time immemorial, so why the problem now?

Well, during a similar outbreak in Brazil a few years ago (See BBC) it was thought that cattle and our need for cheap meat is the root cause. The forest is being cut down to make room for cows and the deforestation is making the Indians' lives harder and they are, as a result, poorer and spend more time sleeping in the open.

On the other hand the cattle which had moved into the cleared areas have become a very good source of food for a growing population of vampire bats. When the cattle owners started putting their cattle into netted shelters at night, swarms of hungry vampire bats started looking elsewhere for food. The tribespeople sleeping in the open have been an excellent alternative for the bats, and inevitably some of these bats carry rabies. This particular form of rabies seems to be quite slow acting (it kills after 7 to 10 days) so the infected people can be bitten by non-infected bats who in turn become rabid and bite each other and yet more Warao tribespeople - not nice!