For 32 years, Mary Mallon, an Irish-born cook who had settled in the US in 1884, was a silent carrier of a bacteria that caused typhoid fever. Mallon, also known as 'Typhoid Mary', infected 51 people before she was identified and sent in isolation twice totalling around 26 years. She finally died in quarantine in 1938.
In India, medical experts say, the biggest challenge is to identify and isolate 'Mary Mallon' of Coronavirus -- the asymptomatic cases of Coronavirus or the silent carriers of the virus.
According to a recent statement by the Indian Council of Medical Research (ICMR), 80 per cent of patients of COVID-19 are asymptomatic in India.
“It took almost a year to find out how a lady was a healthy carrier of dangerous bacteria. One can understand the challenges asymptomatic patients of COVID-19 can pose in India as their numbers could be in lakhs,” Dr Rajeev Ranjan from the Laboratory Medicine Department of AIIMS, Delhi said.
Asymptomatic patients of COVID-19 are those who carry the virus inside their body but don’t show any symptoms such as coughing, sneezing, fever etc. In fact, such patients are themselves unaware that they are infected.
“Their immune system is so strong that virus doesn’t cause any harm to them but it uses them as a means to survive and spread,” Dr Sagar Poudel from community medicine department of AIIMS, Delhi, said.
Poudel also admits that to identify such patients and isolate them seems an indomitable task.
They are also a threat to doctors as they get admission in hospitals for treatment of some other disease but become a source of infection for doctors.
“In many hospitals, doctors were infected as they treat asymptomatic patients for other diseases. They realise it when they themselves develop symptoms,” Dr Adarsh Pratap Singh, President, Residents’ Doctors Association, AIIMS, Delhi, said.
The medical experts said that due to the limited availability of test kits, every patient coming to the hospital for treatment cannot be put to COVID-19 test. Only those who show symptoms undergo a test and till the results are out, they are kept in isolation so that they don’t infect other doctors.
But asymptomatic carriers get admission without any test and carry a risk to health care professionals.
Dr Deepak Sadwani, founder, Prognosis Lab, says, “If one member of family tests COIVID-19 positive, it is still easy to test other members to find out asymptomatic ones. Even if you don’t test everyone, you can at least bring them under surveillance as suspects and isolate them. But what about those asymptomatic cases whose contact history with a positive patient is unknown?”
Till now, contact tracing of a COVID-19 positive patient has been the only way to reach out to asymptomatic ones.
“Either you conduct tests on all 135 crore people in the country to segregate the asymptomatic cases or you trace the contacts of COVID-19 positive patients and test them only. I think the latter one is the logical solution,” Poudel said adding that rapid testing is the only way out.