Unfortunately, pigeons carry a surprisingly large number of diseases that are transmissible to humans (called "zoonoses"). And they have few effective predators, which means that their numbers are fearsome indeed. We probably won't be rid of the ubiquitous pigeon any time soon, no matter how many peregrine falcons make the rooftops of our skyscrapers their home.
The primary means of transmission is through the droppings. The infected pigeon's droppings have the infection vector in them (be it a virus or a bacteria). When these droppings dry, they become powdered and float up into the air as dust, kicked up by passing feet. You inhale the pigeon dropping dust and bingo: pigeon disease.
1. Cryptococcal Meningitis
I was reminded of my former pigeon disease tracking hobby when I read this heartbreaking article in the Canadian newspaper The Globe and Mail, about a woman who contracted an extremely virulent and dangerous form of pigeon-borne meningitis.
She came down with a terrible migraine, then she was hospitalized, fell into a coma for several days, and woke up blind. Richards was lucky to be 23, young and strong and fit. Anyone in lesser health would likely have died.
2. Salmonella and Listeria
We think of these as being food-borne illnesses. But the salmonella and listeria bacteria are also carried by pigeons. These diseases are no joke: listeria is particularly dangerous for pregnant women and babies, as it can cause "meningitis in newborns, abortions, premature delivery, stillbirths, and death."
3. Viral Encephalitis
Pigeons are one of the primary reservoirs of West Nile virus, Western Equine Encephalomyelitis, and St. Louis Encephalitis. These variable diseases can cause anything from temporary illness to permanent nervous system damage or death. They are particularly dangerous to children and the elderly, where they frequently prove fatal.
The transmission vector in the case of these diseases is the mosquito. A mosquito bites an infected bird, then bites a person. As it bites, it backwashes the infected bird's blood into your blood stream. Mosquitoes definitely deserve a whole 'nother level of loathing, as mosquito-borne diseases account for a staggering number of human deaths worldwide.
4. E. Coli
If you are worried about e. coli infections from under-cooked meat, you should also be washing your hands whenever you spend time in a pigeon-rich environment.
Pigeons are extremely effective transmitters of e. coli to humans. It's impossible to say how many e. coli infections in city-dwellers actually stem from accidental contact with pigeon droppings. How many people have written off the last restaurant they ate at, when a pigeon was the real culprit?
Photo credit: Flickr/Danko :)