The recent panic globally, following reports of person-to-person transmission of hantaviral infection on a cruise ship, was reminiscent of early events during Covid aboard another luxury cruise liner - Diamond Princess. While it is expected that the current cluster will end as previous hantavirus clusters did, with only a few deaths, it is yet another reminder that Disease X lurks around the corner.
In Feb 2020, Diamond Princess lay quarantined off Yokohama. Of roughly 3,700 passengers and crew, around 700 were infected and 14 died. Six years on, MV Hondius, returning from Argentina, has produced a cluster of severe respiratory illness, with hantavirus confirmed by PCR, three deaths and rare human-to-human transmission of what is almost certainly the Andes strain, without any threatening new mutations. There is no known spread in India, and the global risk remains low.
Also read: Hantavirus outbreak: How an African lab identified the deadly Andes strain
A small battle may have ended in our favour, but the larger war continues. Disease X - WHO's placeholder for the next unknown pathogen capable of sparking an epidemic - is not a hypothetical threat lurking in some distant jungle. It is a near certainty. Most likely, it will emerge when a respiratory virus jumps from animals to humans among whom we live, work, or trade.
The pattern has repeated itself across half a century of emerging infectious diseases. Each originated in an animal reservoir. Each seized an opportunity created by human-animal contact, and often by delayed recognition and response.
Hantavirus is much more mundane than it is made out to be. The virus has lived inside rodent populations for decades, transmitted to humans through inhaled aerosols of dried rodent urine, droppings, or saliva. This may happen when someone cleans a closed rodent-infested storeroom or a barn containing stored grain. Just a human being, a rodent and a lapse in hygiene. This can happen anywhere, and the reason it has never become a pandemic is that human-to-human transmission is much less frequent than with other viruses on the list. Can a new mutation change this? Yes, and indeed that is the first thing we check for.
Other than the low likelihood of a large Andes strain outbreak, Indian public health has built impressive crisis-response muscle since 2020. What remains to be built, whether in India or elsewhere, is the infrastructure of prevention. The guidance for hantavirus prevention is almost mundane: do not sweep or vacuum dry rodent droppings, wet the area first with disinfectant, ventilate enclosed spaces for 30 minutes before cleaning, wear gloves and a mask, seal gaps around doors, pipes and roofs, and store food in rodent-proof containers. All of it requires awareness and an environment in which acting on that awareness is realistic.
This is where India faces a structural challenge. In a country of 1.5 bn people, human-animal contact is not an exception but a baseline of daily life. Stray dogs and cattle share our streets. Monkeys raid kitchens. Rodents are endemic to grain storage facilities, food markets, railway stations and residential basements. Open drains, uncollected waste and informal slaughter points compound the exposure. The density and proximity are what make a Disease X event more likely here.
Public health messaging in India tends to switch on when a virus is named in the news and switch off when the news cycle moves on. Awareness spikes for a few weeks, then recedes. Hantavirus will follow the same arc unless we treat this moment as an opportunity to do something different.
Also read: Hantavirus: Britain secures experimental Japanese drug to strengthen response
Three shifts would help.
Sanitation and waste management must be reframed as frontline disease prevention. This is in line with already declared priorities, but more is needed.
Surveillance must expand in the background, continuing consistently and widely between news cycles. Again, we have made impressive strides, but not enough.
We need greater public awareness that becomes ingrained as a way of life through a better understanding of and mitigation of exposure risks.
This hantavirus cluster, like the ones before it, will fade from the front pages within weeks. But fading from the news is not the same as the disappearance of pandemic risk. Disease X will almost certainly emerge from the blurred frontier between humans and animals. Our actions will be judged not by how fast we mobilise once it arrives, but by how much we did in the quieter years before.
The writer is dean, biosciences and health research, Trivedi School of Biosciences, Ashoka University.
