West Bengal is in the grip of an unprecedented adenovirus outbreak. Of the 500 samples tested by the National Institute of Cholera and Enteric Diseases from January-February this year, 33 per cent tested positive for this respiratory virus.
The illness is typically one of the upper respiratory tract manifesting as a cough, cold and fever. However, many severe cases have been recorded in this outbreak with three children succumbing to the infection.
Paediatrics beds in both private and government hospitals are all occupied. The same goes for intensive care unit and emergency care beds. Doctors have seen an at least 50 per cent increase in cases this year compared to usual.
“Children have to wait for 48 hours before getting a bed. Emergency beds are also booked. We have had doctors treating patients in ambulances because there is no space in hospitals,” Dr Pallab Chatterjee, a Kolkata-based paediatrician with an interest in pulmonology, told Down To Earth (DTE). “The situation hasn't yet gone into an unmanageable stage but we do have at least 3-4 patients waiting to take one bed. We are functioning at full capacity and are trying our best to figure a way out,” Dr Sanjukta Dey, paediatrician at Kolkata’s Peerless Hospital, told DTE.
Physicians on the frontline believe the increase in adenovirus cases is mainly due to two reasons. Adenovirus has been around for ages but for the longest time, we didn't have enough kits to diagnose the illness. So, it was often just a clinical diagnosis of a respiratory illness, Dr Dey explained.
Now, we are able to diagnose more definitively using the kits and so, the virus is being identified more reliably, the doctor said. “The biofire test, being used here largely for severe paediatric cases, is expensive, costing around Rs 15,000, the doctor said. So, it is not a viable option for all cases and is primarily reserved for those requiring hospitalisation.”
“The PCR test is done for multiple respiratory viruses and adenovirus is one of the viruses on the panel. For adults, the demand for a biofire test isn't so high so we don’t know exactly how many cases there are in that cohort,” Dr Chandramouli Bhattacharya, infectious disease expert at Peerless Hospital, Kolkata, said.
There is no specific treatment for an adenovirus infection — the route is largely one of providing supportive care. A majority of cases Dr Dey has seen are those of co-infections: Adenovirus with parainfluenza, adenovirus with flu or adenovirus with rhinovirus for instance. “Once you have a combination of viruses, you are liable to become much sicker,” Dr Chatterjee explained.
Another possible hypothesis is that the strain of adenovirus might have mutated. Currently, type 3 and type 7 of adenovirus are circulating, which have evolved over the time, Dr Subhrajyoti Bhowmick, also of Kolkata’s Peerless Hospital, said.
The clinical features have changed: High fever not responding to paracetamol, longer duration of illness which is starting with cough and going up to diarrhoea are being reported in many cases, according to medical practitioners. It is basically going through the whole gamut, Dr Dey said.
She has also recorded severe post-infection complications such as cardiomyopathy in the seven months to 11 years age group. “The virus seems to be affecting in a strange way depending on the host, some can have severe side effects but 80-90 per cent of patients have the usual symptoms,” she said.
Dr Bhattacharya posited a similar theory, arguing that we normally expect a lot of upper respiratory tract infections — sore throat, runny nose, fever — which is self-limiting but the past two months have been characterised by patients requiring hospitalisation because their lower respiratory system is being attacked. This typically presents as breathing difficulty and low oxygen saturation. “It is possible the virus changed to have a greater predilection to involve the lungs,” he said.
Breakdown of immunisation chains, particularly for children, during the pandemic also added to the infection-susceptible pool. Doctors also believe that the immunity debt concept has a role to play here — since children were not as exposed to the environment due to the COVID-19 induced lockdown, their immune systems have weakened.
“By design, an immune system is more effective when regularly challenged. So, it would be logical to expect that the immune systems of a major part of the population have been weakened since the pandemic began,” virologist Shahid Jameel had earlier told DTE.
However, lack of scientific evidence doesn’t evoke confidence in this phenomenon. Experts have argued justifying such outbreaks with immunity debt runs the risk of spreading misinformation about the need to be exposed to pathogens to maintain a strong immune system.
While the adenovirus outbreak is being officially reported from West Bengal right now, doctors have been treating patients with similar symptoms in several other cities like Mumbai and Delhi. “If we do widespread testing across the country, the scenario will probably change,” Dr Bhowmick said.