Restore vulture populations to control human rabies


Rabies (perhaps also anthrax and cholera, but via different mechanisms)


Severe vulture population declines and extinction risks for several species


In Asia, the intervention is switching from a commonly-used veterinary drug, diclofenac, which causes vulture mortality, to a vulture-friendly veterinary drug, like Meloxicam.


Populations of threatened and near threatened vulture species


Vultures compete with free-ranging dogs for carrion and thus increasing/restoring vulture populations might limit free-ranging dog populations via competition, thereby reducing the risks that humans will be bitten by rabies-infected dogs.


OBSERVATIONAL: During vulture declines in India, the free-ranging dog population increased despite a sterilization program, potentially due to reduced carcass competition, but other confounding factors could have been important. MODEL/REVIEW: If it works, the Meloxicam switch and other vulture conservation efforts would be COST-EFFECTIVE, especially because the countries with the most priority areas for vulture conservation also have the highest expenditures related to human rabies (e.g., India, China, and Myanmar).


Due to 95-99% vulture population declines, 5 out of 9 Indian vulture species have recently become endangered. VETMED/MODEL: Diclofenac poisoning alone can explain rapid declines in vulture populations. BEFORE-AFTER: Since the 2006 diclofenac ban, Indian vulture populations have stopped declining, but have not yet begun increasing. 


Vulture declines are worst in South Asia and Africa (where rabies risks from free-ranging dogs are highest) and the Iberian Peninsula. Diclofenac may be used less in Africa, so other interventions might be important there. There is a multi-country Asian diclofenac ban.  


Vulture declines occurred over a few decades. It took at least one decade to stop the population declines in India, and restoration may take much longer due to low birth rates.


Hypothetically, decreased free-ranging dog population sizes, number of dog bites reported, and/or rabies cases or deaths, but no such outcomes have been measured yet.


Stabilized vulture population sizes and reduced number/percent of carcasses containing diclofenac


Aesthetics and economic benefits associated with rapidly-removed carrion and spiritual and cultural values associated with vultures (e.g., Parsi religion) 



Restored food web functioning, reduction in contacts at carcasses that are quickly removed and thus maybe less disease transmission among mammalian scavengers


Minor vulture–human conflicts may occur (e.g., smell, nuisance).


None known


Generally socially acceptable (e.g., 94% of Namibian farmers think vultures are useful), but some vulture-human conflicts exist (e.g., farmers think vultures hurt livestock, poachers kill vultures to avoid detection, etc.).



Meloxicam is not as cheap as diclofenac (though it is more effective at lower dose), so the ban might be felt disproportionately by the poorest people. Governments imposing these bans could run assistance programs to fix this issue, if it exists.


If large free-ranging dog populations can outcompete vultures at carrion, additional measures will be needed to restore vulture populations, and it is therefore unclear if vulture restoration alone can reduce free-ranging dog populations. Other threats to vultures still exist (e.g., poison baits, which are toxic to vultures, are used for mammalian predators, especially in Africa.)


Diclofenac is banned in India and surrounding countries, and there is a solid cost-benefit analysis for the ban. But vulture poisoning is ongoing elsewhere; for instance, diclofenac is used in Spain.


Critical need for data regarding free-ranging dog populations, human bite cases, and human rabies incidence to evaluate the human health impacts of the ongoing diclofenac ban.



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Page last updated: 9/5/2020 

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