How Mumbai's well-fed pigeons are killing its residents

Mumbai’s pulmonologists have linked a worrying rise in cases of fibrotic lung disease hypersensitivity pneumonitis or bird breeder’s lung to the city’s exploding pigeon population.While till a decade ago, the hypersensitivity pneumonitis cases would mostly involve people who worked or lived in close proximity to birds — veterinarians, employees tasked with cleaning kabutar khanas (where pigeons are kept) and those who fed birds or resided around bird-feeding points — now people from all walks of life and from all across the city are being detected with acute lung damage.Hypersensitivity pneumonitis is an immune system disorder caused by inhaled organic antigens or low molecular weight chemical compounds. These substances trigger the immune system, causing short- or long-term inflammation, especially in a part of the lungs called the interstitium, and thus the umbrella term interstitial lung disease. medium98152481Pigeon droppings and dust that rises when it is swept off a surface is the most common form of allergen that causes hypersensitivity pneumonitis. The droppings contain fungi like aspergillus which, when inhaled, can cause histoplasmosis, which can lead to interstitial lung disease, more specifically hypersensitivity pneumonitis.In Mumbai, experts believe that the number of hypersensitivity pneumonitis cases has risen fivefold in the past seven-eight years. Doctors have also observed hypersensitivity pneumonitis cases progressing into chronic hypersensitivity pneumonitis or pulmonary fibrosis, which is irreversible scarring of lungs.Chronic hypersensitivity pneumonitis requires a patient to be on 24x7 oxygen support and there is no treatment available to reverse the damage except lung replacement. medium98185575Watch: 'My husband's condition deteriorated soon' medium nocaption98172368Dr Lancelot Pinto, consultant pulmonologist and epidemiologist at Hinduja Hospital, says that while earlier he would come across one or two cases of hypersensitivity pneumonitis in a month, the number has now grown to four to five in a week. He says most of the patients, when asked if they have pigeons around their house, say their balconies, spaces outside windows and ducts are overrun by them.The Indian Chest Society, a body of pulmonologists and chest physicians, recently carried out a study on interstitial lung disease. The study, under which 1,100 samples from 23 medical institutes were collected, found that hypersensitivity pneumonitis is the most common cause for interstitial lung disease and nearly all cases of hypersensitivity pneumonitis reported for this study had exposure to pigeons.Dr Virendra Singh, former president, Indian Chest Society, and senior pulmonologist and president, Rajasthan Hospital in Jaipur, says the study was instituted after doctors at the society’s annual conferences began mentioning more and more hypersensitivity pneumonitis cases in discussions. “The study concluded that hypersensitivity pneumonitis accounts for almost 47% of all interstitial lung disease with pigeon droppings being the common link,” he says.The study has not only been accepted by the European Respiratory Journal, but the Indian Council of Medical Research has now begun developing a registry for interstitial lung disease. “The registry will help us to frame a policy to control the pigeon population,” Dr Singh says. medium98152094How pigeons edged out other birdsOrnithologist Mohammed Dilawar, president, Nature Forever Society, attests that pigeons now outnumber any other species of birds in the city by a very long margin. He says pigeons, originally cliff-dwelling, adapted to living in cities decades ago, but their numbers were never this high.A well-fed pigeon on an average dispenses up to 11.5kg of droppings a year. Bird experts say the unregulated practice of feeding, especially at kabutar khanas, is one of the main reasons for the explosion of the pigeon population. The other being the absence of natural predators.Dr Sujit Rajan, who is attached to Bhatia Hospital and Bombay Hospital in Mumbai, says he sees up to two dozen cases of interstitial lung disease in a week with at least three or four already in progressive fibrotic stage, which essentially indicates 70-80% tissue damage.Watch: Mumbai doc on perils of pulmonary fibrosis medium nocaption98172253“A lot of people are not aware of the cost of living in proximity to pigeons. They see local physicians for breathing problems. By the time they consult a specialist, it is too late. What is most distressing is seeing many young patients in an advanced stage of lung fibrosis,” he says.Pulmonologist Dr Prahlad Prabhudesai, who is attached to Lilavati Hospital, says the symptoms of hypersensitivity pneumonitis are mistaken for two common diseases — influenza and bronchial asthma — because the initial symptoms are similar. “It is important that chest physicians should advise CT scan of lungs if the symptoms persist for more than five weeks. It is distressing to see patients approaching us when substantial damage to lungs has already taken place,” he says.Dr Prabhudesai says Mumbaikars must do themselves a favour and stop feeding birds. “You are only inviting trouble. It is easy to see how the city has been overrun by pigeons. Also, people must wash the outdoors — balconies, the space outside the windows, ducts — frequently to prevent the accumulation of pigeon droppings.”medium98295799Renowned pulmonologist Dr Zarir Udwadia says the only way the mounting cases of hypersensitivity pneumonitis in Mumbai can be controlled is by stopping feeding of pigeons. “Pigeon exposure triggers interstitial lung disease, which is the commonest form of lung fibrosis encountered in India,” he says.Dr Namrata Jasani, senior pulmonologist at Global Hospital, Parel, says people with no history of lung disease are being diagnosed with sensitivity pneumonitis. “The lockdown is one of the reasons, I think, why cases have shot up. People worked out of homes and they would keep the windows open, not realising the dust they breathed carried pigeon fungi,” she says.Watch: How pigeons are harming Mumbaikars' lungs medium nocaption98172176Dr Jasani also stresses the importance of early detection. “If it is caught within six weeks, hypersensitivity pneumonitis is reversible. But in most cases patients approach us very late, when the damage has already progressed to the irreversible stage,” she says.Dr Jasani recently saw a 32-year-old who had no history of any lung distress and no comorbidities like blood pressure or diabetes. “This man developed such bad breathing congestion that we had to shift him to the ICU [intensive care unit], where he spent two months. He told us about pigeons laying eggs outside his window. We advised him to either close the space outside his window or move to another house. If he continues to be exposed to pigeons, he will be in trouble again,” she says.Photos and videos by Raju Shinde