Watch out, it’s raining bacteria

If the adage is to be believed, getting wet in the first rains of the season is good for you. But according to a study conducted by a team of researchers from the Department of Environmental Science at the Bangalore University, it's preferable to stay out of the rain altogether. The study has revealed the presence of pathogenic bacteria including E Coli, which could lead to various health problems in the sodden individual.

The year-long study collected samples from the summer's first rain and the hailstorms that the city received. They revealed that apart from E coli, evidence of Streptococcus spp, Staphylococcus aureus, Enterococcus spp, Actinomyces spp, Bacillus subtilis, Neisseria spp, and Mycobacterium sp was seen.

The study, which was conducted by the chairperson of the department, Dr Nandini N, and research scholar Sivasakthivel S, stated that these bacteria could cause illnesses like meningitis, bacterial pneumonia, endocarditis and necrotizing fasciitis, especially in children and people whose immune system had been suppressed. They also led to skin allergies and rashes.
The study stated that E Coli, Pseudomonas spp, and fungal species like Fusarium spp, and Alternaria spp, populated the breathing zone up to 1.2 to two metres. The number of organisms, however, reduced by 68 per cent above the breathing zone. The bacterial and fungal pollution randomly decreased after the rains. The population density of microbial pollution decreased from 67cfu/m3 (colony forming unit per metre cube) to 38cfu/m3.

“These fungal species can cause infectious disease, have acute toxic effects, and give rise to allergies and cancers. The study revealed that initial rain, during summer, enhanced the bio-pollution emission from the soil surface and other sources, which is harmful to humans beings,” Dr Nandini said.

Explaining further, she added that during summer there is a lot of dust and particulate matter in the atmosphere, which settles in the stratosphere. Hence, when the first rain occurs, all microbes that were growing in the atmosphere are brought down to the soil. But once regular rainfall commences the atmosphere clears of microbes. Also when the initial rain hits the soil, the fungi in the ground are sent into the air, in the form of bio-aerosols. These bio-aerosols are very dangerous and when people breathe them in, they give rise to respiratory problems.

Dr Nandini pointed out that the levels of bio-pollution in Bangalore's air were very high, and needed to be addressed. The study will now be submitted to the government and patented. In the next step, the researchers are recording data of variants and temperatures.

“We want to make a complete record — seasonwise, timewise, and regionwise study of the organisms. After which it will be analysed to find out which organism has seen an increase, at what time of the day, and where and how it can be controlled.