Street Saviors


Written by Merrit Clifton • Special Features • October 2010

7-1 Following floods of apocalyptic magnitude, most people in Pakistan probably do not want to think about dogs. But this is the time, especially in the areas that were flooded, to hope there are enough healthy dogs left to protect the nation from a potential epidemic of leptospirosis.

Leptospirosis thrives in recently flooded areas. About 90% of those who are infected have only flu-like symptoms, but about 10% become seriously ill, and 10% of them die, typically of painful renal failure.

Leptospirosis may be spread by almost any mammal, but mostly it is spread with the urine of rats and mice, and infects humans through exposure to contaminated water.

This was no small issue in Pakistan even before the 2010 monsoon floods. Pakistan's health director general Rashid Jooma in November 2009 told the 13th National Health Sciences Research Symposium that 24% of the hospital beds in Pakistan were occupied by people suffering from waterborne diseases.

Data produced by the Pakistan Science Foundation shows that more than half of the people and livestock in Pakistan have already had some exposure to leptospirosis, if not enough to become actively infected.

Dogs, like most mammals, can contract leptospirosis. But dogs are mostly the front line of defense against it. Dogs consume food waste and other refuse that might otherwise feed rodents. Dogs hunt rodents, who are much less likely to infest a house where dogs are present. And, having evolved as scavengers, dogs have greater resistance than most animals to infectious diseases, including leptospirosis.

Since dogs are often thought of in Pakistan as "unclean," precisely because they are scavengers, the notion that dogs have a vital role in protecting human health may surprise many readers. But the notion that dogs are "unclean" and potentially dangerous is historically associated with just one disease, rabies, an infection so virulent that it rapidly kills the host. Surviving only if an infected victim bites and infects another victim before dying, rabies has justly been feared since ancient times.

Yet rabies can also be eradicated by vaccinating dogs. Canine rabies has now been eliminated from the U.S., Brazil, Argentina, Uruguay, the whole of western Europe, and even the cities of Chennai, Jaipur, and Visakhapatnam in India.

Currently Pakistan - like much of the rest of the developing world - still tries to fight rabies by administering post-exposure vaccination to humans who have been bitten by suspected rapid dogs, and by killing dogs in the vicinity of rabies outbreaks. Decades ago this was believed to be the most cost-effective approach; but no longer. The World Health Organization points out that thousands of dogs can be vaccinated at less cost than safely handling even one human rabies fatality. Hundreds of dogs can be vaccinated at less cost than administering even one dose of human post-rabies exposure vaccine.

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Killing dogs, contrary to common belief, has never been effective in fighting rabies at all. The logic of exterminating dogs does appear inescapable: kill them and they will be no more. Yet life had already evolved a counter-strategy many hundreds of millions of years before humans existed. All species, from the leptospirosis spirochete and rabies virus to blue whales, reproduce up to the carrying capacity of their habitat, as rapidly as possible. If one species succumbs to disease, disaster, or predation so rapidly that it cannot fill the habitat, another species moves in. Never does nature allow habitat to go unoccupied. Until the carrying capacity of cities for hosting dogs is permanently reduced by instituting effective sanitation, killing dogs just removes a major check on the growth of the rat and mouse population.

Policymakers in Pakistan, as elsewhere in the developing world, often seek for their cities the superficially animal-free, clean appearance of a "modern" city that they see in Europe and the U.S. - and this aesthetic notion is often associated with the hope of eliminating rabies. But casual observation of European and U.S. cities by daylight is deeply deceptive. European and American cities currently support even more dogs, cats, and wild animals per thousand humans than the cities of the developing world. They have merely achieved a transition from hosting outdoor animals, seen in daytime, to hosting mostly indoor pets and nocturnal wildlife.

U.S. urban sanitation circa 1950 was quite similar to that of Pakistan - at least the parts that escaped flood damage. In 1950 pioneering demographer John Marbanks found that the U.S. had about 10 million street dogs, among about 30 million dogs total.

Within 30 years the U.S. street dog population had disappeared, but not because Americans killed them all, though many cities tried, or had fewer dogs. In fact, the U.S. had almost twice as many dogs.

In the interim, the U.S. human environment evolved through the advent of refrigeration, reliable garbage collection, and enclosed sewers and dumps. Instead of supporting dogs who scavenged rats and refuse, the U.S. came to support dogs who consumed slaughterhouse offal and other food waste that was processed into pet food, fed to them in human homes. Unvaccinated street dogs had been replaced by an almost equal number of vaccinated pets - and canine rabies in the U.S. was soon to become history.

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But the elimination of street dogs and rabies from the U.S. did not mean fewer dog bites, for reasons also worth recognition in Pakistan. Street dogs freely wander among humans all day, every day, but rarely bite anyone, unless they are rabid, because dogs who bite people tend to be quickly culled. Because street dogs have no particular home, they are relatively non-territorial. Neither do they have anyone to defend except their own pups. Dogs kept in a home become territorial and protective. Tripling the number of dogs kept in homes in the U.S. between 1950 and 2010 brought an eightfold increase in the number of dog bites requiring hospital treatment.

The number of U.S. dog attack fatalities rose from circa one every five years at mid-century to 33 in just the first eight months of 2010. Twenty-seven of those fatalities were inflicted by pit bull terriers, a breed constituting just 4.1% of the U.S. dog population - and a breed so artificially created through line breeding, or systematized inbreeding, as to have no resemblance to street dogs anywhere. The pit bull traits are not conducive to the survival of a street dog, who depends above all else upon being inconspicuous, non-problematic, and socially well-adapted to the proximity of both humans and other animals.

Pakistan already has some pit bulls, used in illegal dogfighting and bear-baiting, and kept by certain criminal elements to protect their activities. Unfortunately, these dogs will not be of much use in preventing leptospirosis, because they cannot be safely allowed to run free to hunt rats.

The dogs whom Pakistan needs are the dogs who have co-evolved with the civilization, the street dogs, who have shared with humans every hardship. They need vaccination against rabies. They might appreciate an occasional kind word, or treat.

All they ask, though, is tolerance as they go about their work of helping to protect society.