Worms and Germs Blog
Cows to vultures to dogs to rabies: unintended consequences
"Unintended consequences" are outcomes (usually negative) of a particular action that are unexpected. For example, in some areas, hospitals now receive decreased reimbursement for MRSA infections. This policy was meant to help encourage hospitals to reduce MRSA infection rates. However, there are concerns are that this has actually lead to decreased MRSA testing (and potentially compromised patient care), because if the MRSA infection isn't documented, payment will not be withheld.
Unintended consequences can be found in many diverse areas. An interesting example was recently published in Ecological Economics and reported by the Toronto Star. It described the unintended consequences that linked use of a cattle drug to rabies deaths in India. Here's here story:
- Didofenac is a drug that was routinely used in cattle in India
- The drug is apparently highly toxic to vultures
- Vultures fed on cattle that died of natural causes, but that had didofenac in their bodies
- Millions of vultures died, which led to a larger food supply for feral dogs
- It was estimated that this lead to 5.5 million more feral dogs in India from 1992 to 2006
- These additional dogs would have accounted for at least 38.5 million dog bites
- Rabies is a serious problem in feral dogs in India
- In India, 123 people die of rabies per 100 000 dog bites.
Putting these numbers together, the unintended consequences of didofenac use in cattle may have result in 47 000 human deaths from rabies and $34 billion in health care costs. There are a lot of assumptions in this report, but it is an interesting story and highlights the unpredictable nature of infectious diseases, and the varying effects that seemingly unrelated actions can have.
More information on rabies can be found on the Worms & Germs Resources page.
University of Guelph
Guelph, Ontario, N1G2W1, Canada.