Given the two major outbreaks of 2018, what are the current threats when it comes to viral diseases?
The basic threats that we face currently are the dengue and chikungunya viruses. However, since Zika has now established itself in the country, it is a major concern for us. In 2017, after four cases were detected in the country, we had predicted that Zika would soon emerge as a public health concern, given our experience with the chikungunya virus that reappeared after more than three decades. At NIV, however, we had been preparing to deal with the Zika virus since 2015 by building capacity for testing. We had also studied the natural life cycle of the virus and its modes of transmission. This was being done in collaboration with the Centre for Disease Control, Atlanta.
How do we understand the current spate of viral diseases?
The presence of the virus in our ecosystem is not new. Viruses have been there for centuries. In India, the presence of the dengue virus was first detected in 1956. The rare, deadly CCHF virus (Crimean-Congo haemorrhagic fever) was also first detected in the country by the NIV in 2011. The NIV has detected 26 new viruses until now. However, what is being seen now is that the viruses are jumping hosts—from animals, where the viral disease is asymptomatic, to humans, where they can prove to be deadly. Viruses also replicate very fast, with several mutations taking place in a matter of seconds, like the influenza virus.
Viral diseases are rising, and the majority of new diseases are zoonotic (from animals to humans). Of these, a majority comprises of viral diseases where birds are the primary hosts, and about 30-40 per cent are where the hosts are bats.
The reason for the deadly outbreak of different viruses can be attributed to various reasons such as large-scale deforestation and urbanisation. Cities are becoming congested, allowing for the mosquito to breed in abundance. This mosquito is then becoming an active host to different viruses. By cutting our forests, we are also now going closer to wildlife, and subsequently, the viruses. Take for instance, the Nipah virus and its host, the fruit bat. Climate change has also altered the ecology—the places that used to be warm and cold are no longer so.
What about new vaccines to deal with the viruses?
Research is on to find vaccines for various viral diseases such as Zika and dengue. But the question is can we provide vaccines for the entire population, given the huge costs involved? Are vaccines the solution for a country like ours? We need to hit at the root of the problem—the breeding of the Aedes aegypti mosquito, for instance. The Aedes mosquito breeds in places where clean water is stored. Here, individual responsibility matters. People need to ensure that water storage sites inside the home do not become breeding grounds. Besides, we also need to increase awareness around personal hygiene and encourage simple practices such as hand washing. This will help prevent the gastric diseases that spread through the excreta of dogs and pigs, especially in the rainy season.
What is the current status of expertise in India in the field of virology?
We are really short of experts in the field—the requirement is 20 times more than what we have now. Besides, the best in the field do not choose to specialise in virology, because it is a tough one. However, we intend to start PG courses in the subject to augment the manpower that we require.