What’s in a gutter? There is a lot in a sewage that could provide vital clues to crippling diseases like polio, particularly for a country like India, which has just successfully controlled this major health menace. Researchers will now scour the sewage in select cities to find out if polio virus thrives in the dirty waters. India had last reported a polio case 18 months ago and it still needs a few more months to qualify for the polio elimination certificate. If no polio cases are reported for another five years, the World Health Organisation will declare polio as eradicated from India.
Polio virus is shed through faeces. Even the oral polio vaccine, which is a live but attenuated virus, also causes shedding of the virus through faeces. So, analysing sewage samples reveals if the virus is circulating in the drains. Since transmission of polio virus is through faeco-oral route, any contamination of drinking water may lead to resurfacing of the problem. Apart from zero clinical cases of polio, zero positive results from sewage are also important to win the war against polio.
Teams from WHO will collect sewage samples from different cities for analysis. Samples collected last year from Delhi, Mumbai and other places did not show the presence of the virus. However, as a precaution, it will take up sewage scouring in more cities to be doubly sure there is no polio virus circulating in the sewer lines. WHO is concentrating on Punjab now.
Authorities in Hyderabad have yet to receive an official message from WHO for sewage sampling. GHMC chief medical officer Dr D. Shalini said, “We have not yet carried out sampling of sewage for poliovirus. However, we do occasional testing of faecal samples for acute flaccid paralysis in suspected polio cases.”