NEW DELHI: The WHO on Wednesday confirmed that a rare strain of Hantavirus, known to spread from person to person through close contact, has been found in patients linked to an outbreak aboard a luxury Dutch cruise ship.
The World Health Organisation (WHO) said it is working with countries to trace those exposed to the Zoonotic virus so that the spread of the disease is limited.
However, both international and national experts said that the risk to the global population from the outbreak is low.
The hantavirus outbreak due to the Andes strain has led to several infections and three deaths, including those of a Dutch couple.
Quoting the health ministry in South Africa, the WHO said the Andes strain of the virus, which is prominent in Latin America where the cruise originated, has been detected in two people who were evacuated from the ill-fated ship to the country.
Apart from two confirmed cases in South Africa, Swiss authorities also confirmed a case of hantavirus was identified in a passenger from the MV Hondius cruise ship, which started from Argentina across the Atlantic. The patient is receiving care in Zurich, Switzerland.
As of Wednesday, the WHO said there are eight cases, three of which are confirmed as hantavirus by laboratory testing.
“Three suspected #hantavirus case patients have just been evacuated from the ship and are on their way to receive medical care in the Netherlands in coordination with @WHO, the ship’s operator and national authorities from Cabo Verde, the United Kingdom, Spain and the Netherlands,” WHO Director-General Tedros Adhanom Ghebreyesus said.
He said the WHO continues to work with the ship’s operators to monitor the health of passengers and crew closely and to support appropriate medical follow-up and, where needed, evacuation, in coordination with countries.
“Monitoring and follow-up for passengers on board and for those who have already disembarked have been initiated in collaboration with the ship’s operators and national health authorities,” he added.
“At this stage, the overall public health risk remains low,” he further said.
WHO also said they are contact tracing passengers who travelled on a flight with the two evacuated passengers from the luxury cruise between the remote South Atlantic island of Saint Helena and Johannesburg, and who later died of the rare virus.
As many as 150 people are still aboard the cruise ship, which has been anchored near Cape Verde in the central Atlantic Ocean, 620 km off the West African coast, since May 4. It is headed to the Canary Islands.
The passengers have been asked to follow “strict precautionary measures.”
According to WHO, the virus is primarily acquired through contact with the urine, faeces, or saliva of infected rodents. It is a rare but severe disease that can be deadly.
Speaking with this paper, Dr Rajeev Jayadevan, Co-Chairman of the National IMA COVID Task Force, said, "The Hantavirus family has many members, of whom the Andes virus is known for its ability to spread from person to person. The virus on board the ship has been confirmed to be the Andes virus, and this explains the apparent spread of the virus among the occupants of the ship."
He added that hantavirus is not known to have pandemic potential because its ability to spread from person to person is low.
“Standard quarantine and preventive measures are enough to stop the spread, and all such measures are being taken by International health authorities and national agencies who are closely monitoring the situation. Therefore, with the information available so far, there is no need to be concerned about a new pandemic,” he added.
Depending on the species, Hantaviruses can remain asymptomatic or cause severe lung disease or kidney damage. “The problem with developing pneumonia following Hantavirus infection on a cruise ship at sea is that immediate advanced ICU care is often not an option. This can potentially affect survival as the disease can progress rapidly,” he added.
He said how the Andes virus entered the ship remains a matter of speculation.
“As this was a wildlife expedition involving hiking and trekking in wooded areas inhabited by rodents, it is possible that one or more of the passengers may have picked up the infection and brought it back to the ship, subsequently spreading it to others,” he added.
Dr Jayadevan said this explains how the passengers were infected.
“The virus could have spread when the person was not having symptoms and was mingling freely. This virus has an incubation period ranging from one to eight weeks.”
The ship was carrying a total of 147 individuals, including 88 passengers and 59 crew members.
In the Americas, infection can lead to hantavirus cardiopulmonary syndrome (HCPS), a rapidly progressive condition affecting the lungs and heart, while in Europe and Asia, hantaviruses have been known to cause haemorrhagic fever with renal syndrome (HFRS), which primarily affects the kidneys and blood vessels.
While there is no specific treatment that cures hantavirus diseases, early supportive medical care is key to improving survival, which focuses on close clinical monitoring and management of respiratory, cardiac and kidney complications. Prevention largely depends on reducing contact between people and infected rodents.
In East Asia, particularly China and the Republic of Korea, HFRS continues to account for many thousands of cases annually, although incidence has declined in recent decades.
South American countries such as Argentina, Brazil, Chile, and Paraguay report few cases annually. Despite the lower incidence, HCPS has a high case fatality rate, commonly between 20% and 40%, making it a disease of major public health concern, the WHO said.
Early diagnosis of hantavirus infection can be challenging because early symptoms overlap with those of other febrile or respiratory illnesses, such as influenza, COVID-19, viral pneumonia, leptospirosis, dengue, or sepsis.
There is no licensed specific antiviral treatment or vaccine for hantavirus infection.
Care is supportive and focuses on close clinical monitoring and management of respiratory, cardiac and kidney complications. Early access to intensive care, when clinically indicated, improves outcomes, particularly for patients with hantavirus cardiopulmonary syndrome.