People with low immunity are most vulnerable. Pigeon droppings cause secondary infections to those who are already ill.
“Pigeon droppings will affect the passengers if they are not cleaned for a long time. In Metro ceilings, on air conditioner vents and beside stairs, there are pigeon droppings that not cleaned regularly. If dried faeces are disturbed, they turn to aerosols. Aerosols spread in the air and can cause lung diseases among people who have low immunity,” Dr K.M. Chandrashekar, former assistant professor, veterinary microbiology, Veterinary College, informed The Observer.
An aerosol is the suspension of organisms in a droplet. It spreads in the air and enters the human body.
Pigeon droppings can cause secondary infections among people who are anaemic and sick, he added.
Veterinary microbiologists at the Karnataka Veterinary, Animal and Fisheries University say pathogens in pigeon droppings can cause up to 60 different diseases.
Pigeon droppings have more creatinine, an organic compound, than in the excreta of other birds. It creates pathogens, bacteria, viruses or other microorganism that can cause diseases. When pathogens in pigeon droppings mix with soil, they turn to Cryptococcus and Histoplasma,fungi that affect people with low immunity, particularly those who have advanced AIDS and cancer. These fungi also affect the respiratory organs of anaemic people.
Cryptococcus neoformenas is a fungus seen mostly in dried pigeon droppings. It can even cause the death of AIDS patients. Psittacosis, also called parrot fever, is another infectious disease transmitted by bird droppings.
Pigeons are uricotelic – meaning they excrete nitrogenous waste from bloodstream as uric acid instead of urea and ammonia. Like other birds, they don’t have a urinary bladder, so their urine mixes with faeces, making them semi-solid. Uric acid is converted to ammonia that can spread in air.
“If the pigeons are dangerous, then the BMRCL should take action. It doesn’t mean BMRCL should kill them, but it can prevent the pigeons from entering the Metro stations and dirtying the place,” said Mahalakshmi, a Metro commuter.
BMRCL has installed dartboards in the Trinity station to drive pigeons away. But the dartboards are only placed at the entrances and exits, not inside the station. Pigeons are seen all over the station.
The Environment (Protection) Act, 1986, says the government should take appropriate steps for the protection and improvement of human environment. The ministry of environment, forest and climate change is the body responsible for implementation of the Act.
“Workers clean the Metro stations regularly. The floor is cleaned every 2-3 hours, and heavy cleaning is done at night. Instructions are given to contractors who take care of the cleaning teams. We gave guidelines for them to wear gloves and masks while cleaning,” B.L. Yeshwanth Chavan, BMRCL chief PRO, said.
Susila Anand, a Metro worker said: “We clean the floor many times a day. We are provided with gloves, masks and coats. We wear the gloves and masks only while cleaning dusty areas.”
Pigeon droppings become dangerous when they dry up. Those who clean them without protection are at high risk as they breathe the aerosol. It can lead to lung problems.
“We can prevent infection by moisturising it before cleaning. If it is moisturised, it won’t spread in air. Those who clean pigeon droppings should be healthy and take precautions like wearing masks, gloves and aprons,” Chandrashekar said.
If bird faeces come in contact with injuries, harmful organisms enter the blood stream. In December 2018, a child died of Cryptococcus at Queen Elizabeth University Hospital, Glasgow. The autopsy report showed that inhaling of fungus was the primary reason of death.
Chandrashekar has conducted awareness programmes to let people know that pigeon droppings can spread parasites, ticks and fleas in the environment.