It’s March in Patagonia, the Nire and Lenga trees are just starting to take on autumn hues. A 70-year-old man and his wife are out birdwatching and get caught in an unexpected rainstorm. They take shelter in an old farm shed. They do not notice the rodent droppings on the floor, or the faint plume of dust that rises when the man leans against a stack of bags of dry grain. Thirteen days later, on April 1, the couple are aboard the MV Hondius when it departs Ushuaia, a port city at the southernmost tip of Argentina. On April 6, the man comes down with a fever, a headache, and mild diarrhoea. By April 11, he is dead.
We do not know exactly how the first patient on the MV Hondius got infected with the Andes Hantavirus, but the scenario I described above is a plausible one, pieced together from the available facts. And we do know that he became ill by April 6 and died aboard the ship on April 11. His 69-year-old wife died on April 26 in Johannesburg, South Africa, just days after she disembarked with her husband’s body on the island of Saint Helena. A German woman died aboard the ship on May 2. A French woman was put on extracorporeal life support at Bichat Hospital in Paris. Sixteen Americans have been evacuated to a special facility in Nebraska, and another two are in a bio-containment unit in Atlanta. Twelve Dutch laboratory workers are in six-week quarantine after handling samples from an infected patient.
Our collective response to this outbreak says as much about us as it does about the virus. It’s been more than six years since Covid-19 first emerged, and yet a virus that spreads much more poorly has made the world flinch. Cape Verde, the country closest to the Hondius when news of the infections broke, refused to let the ship dock at all, citing limited healthcare system capacity. The President of the Canary Islands, a Spanish territory, had intended to block the ship from anchoring at the island of Tenerife until the central government in Madrid intervened. The Director-General of the World Health Organisation, Tedros Adhanom Ghebreyesus, flew to Tenerife in person and wrote a letter reminding its residents that “the best immunity any of us has is solidarity”.
On the whole, however, officials and experts around the world have scrambled to respond to this frightening situation and to understand what the risks are. And indeed, knowledge of these risks is critical. The WHO has said hantavirus “spreads differently” from Covid-19 or the flu. And the situation on the Hondius has shown what “differently” means.
Of the roughly 150 people who inhabited the ship for six weeks, 11 have become ill and three have died. Another 122 evacuees are now in monitored quarantine in eight countries. Compare this to the Covid-19 outbreak aboard the Diamond Princess cruise ship in February 2020: 712 Covid cases among 3,711 passengers and crew in less than half the time. Andes virus is absolutely terrifying, especially for the people it infects and for their loved ones. But will this virus become the next pandemic? Absolutely not.
To understand the situation better, it helps to start with the basics. Hantaviruses establish lifelong infections within specific rodent species. Andes virus has co-evolved with the long-tailed pygmy rice rat, a rodent found in southern Argentina and Chile. The virus causes little to no disease in its natural host; the pygmy rice rat’s immune system tolerates the virus, and the animal stays healthy enough to live and breed while it sheds the virus in urine, droppings and saliva for months on end. Human infections are unlucky accidents that occur on a planet that eight billion of us share with a great many other animal species. The adaptations that let a virus persist harmlessly in a rodent or bat are, in these rare and frightening spillovers, the same ones that make it deadly in people.
To be fair, it is indeed concerning that the Andes Hantavirus is the one hantavirus that has been documented to spread from person to person. But the numbers are reassuring. In a prospective study of 476 close contacts, the overall secondary attack rate was 3.4 per cent. Among sexual partners of an index case, the rate was 17.6 per cent, or roughly one in six. Among other household contacts, just 1.2 per cent. For comparison, measles has a basic reproduction number – the expected number of cases generated by one case – of 12 to 18; Covid-19 early in the pandemic, between two and five.
Why does a cruise ship matter for a virus that doesn’t easily transmit through casual contact? Closed quarters, shared dining areas, sustained close contact: these were the conditions that turned a 2018 Andes Hantavirus outbreak in the village of Epuyen, Argentina, into a chain of 34 cases and 11 deaths that began at a birthday party and rippled through funerals and close household contacts over the following months. The same long incubation period – two to six weeks from exposure to symptoms – is why the European Centre for Disease Prevention and Control has requested that passengers who disembarked from the MV Hondius quarantine for a full 42 days.
For people infected with the Andes virus or who have been exposed to it, fear is justified. The case fatality rate of Andes virus runs between 25 and 40 per cent, in the same range as Ebola in treated outbreak settings. There is no licensed vaccine and there are no effective antiviral drugs. Early symptoms are a “flu-like” syndrome and clinicians outside Argentina and Chile rarely think to test for hantavirus. By the time hantavirus is diagnosed, a patient is often in shock, with respiratory failure, cardiac dysfunction and, frequently, acute kidney injury.
It’s important to point out that some aspects of the global response worked out well during this episode. For example, the EU Civil Protection Mechanism was activated within days, Norway dispatched a rescEU air ambulance and laboratories from Dakar to Johannesburg to Atlanta have shared samples and sequences in near-real time. But it’s hard to ignore that Argentina – where the index case is thought to have been infected – and the US, which has 16 evacuated citizens under monitoring in Nebraska, recently reaffirmed their intent to leave the WHO.
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A person wearing a white hazmat suit leaves a plane believed to be carrying passengers from the hantavirus-hit cruise ship MV Hondius, before being escorted to an ambulance, at Amsterdam's Schiphol Airport in the Netherlands. AFP -
MV Hondius leaves Praia, Cape Verde. Reuters -
A convoy of ambulances believed to be carrying at least one person from the cruise ship is escorted by Dutch police in Leiden. AFP -
Security staff at the entrance to the Gomez Ulla Military Hospital in Madrid, where 14 Spanish citizens from the MV Hondius are to be quarantined. Reuters -
A second plane believed to be carrying a sick passenger arrives at Schiphol airport. AFP -
The entrance to the University Hospital in Dusseldorf, where a 65-year-old German woman passenger was taken for treatment. AFP -
Medics await the arrival of a medical plane at the Schiphol airport. AFP
Life-saving advances, such as new vaccines and diagnostics, are made possible when less wealthy nations rapidly share data and patient samples during disease outbreaks. However, if wealthier countries fail to promptly and equitably share such advances with poorer nations, then the incentive to co-operate collapses into suspicion and betrayal. We saw that bitter dynamic play out during Covid-19: the most effective vaccines were available only in wealthy countries, and when poorer countries rapidly shared data on new variants, they were rewarded with travel bans.
Science and vaccines are themselves fruits of international co-operation. To defeat infectious diseases, we must work together – to treat the ill, to share what their cases teach us, and to develop and deploy effective countermeasures. The notion that any country can fare better than another by thinking only of its own needs is as myopic as it is misguided. Infectious diseases do not discriminate between rich and poor, and pathogens have no regard for international borders. But luckily, co-operation, compassion, curiosity, creativity, intelligence and innovation comes from rich and poor alike, and from all national origins. These human qualities are essential to solve countless vexing challenges, including how to protect ourselves from diseases.
Certainly, the MV Hondius is a wake-up call. It took countries on four continents, biocontainment units and the co-ordination of the WHO to manage 11 cases of a virus we have known about for 30 years. So many years since the Covid-19 pandemic, one might expect that we’d be better prepared for the next “big one” (which, fortunately, this hantavirus is not). But smaller international health events like this demonstrate that in order to get to that stage, we still have some ways to go in addressing the fraying fabric of trust in each other, and in science, that makes effective responses possible. World leaders must ensure that the right partnerships and incentives are in place to ensure equitable distribution of medical and humanitarian assistance during outbreaks, and that patient samples and data flow as freely during public health emergencies as commerce and trade do during times of prosperity.
