Keeping Threat Of Hantavirus At Bay

The hantavirus has been in the limelight since the Dutch cruise ship, the MV Hondius, saw an outbreak in April and May. Eleven people aboard the ship were infected, with three fatalities. Health officials coordinated the repatriations of the passengers and monitored the situation. The ship arrived in Rotterdam on May 18, and every passenger and crew member was retested and left the ship. The ship was then disinfected. 

Hantavirus disease is a zoonotic disease. The hantavirus affects rodents but can also occasionally affect humans. The disease is transmitted through the body fluids such as saliva, urine and droppings of rodents, especially rats. The symptoms manifest themselves one to eight weeks after exposure to the virus and include fever, headache, myalgia and gastrointestinal symptoms such as colic, nausea or vomiting. The manifestations of the symptoms vary depending on the types of viruses and geographical location.  

There are many types of hantaviruses, but only a limited number are known to be pathogenic. In the Americas, the pathogen causes hantavirus cardiopulmonary syndrome with fatality up to 50 per cent. This condition is rapidly progressive and affects the lungs and heart. Its symptoms include cough, dyspnoea, pleural effusion and shock.   In Europe and Asia, the hantavirus causes haemorrhagic fever with renal failure, which affects the kidneys and blood vessels. The fatality rate is put at one in 15 per cent. The disease in later stages causes hypotension, bleeding disorders and renal failure. 

Worldwide, 10,000 to over 100,000 infections are reported annually, with Europe and Asia bearing the brunt. In East Asia – particularly China and the Republic of Korea - haemorrhagic fever with renal failure affects thousands of people each year. But the trend has dwindled in recent decades. In Europe, several thousand people get infected each year. In the Americas, hundreds of cases are reported annually. Hantavirus cardiopulmonary syndrome is rare but fatal, with a fatality rate of 20-40 per cent. Therefore, it is considered a public health concern. 

The one detected on the Dutch cruise ship is the Andes virus, which, unlike other variants, can spread from person to person, as corroborated by previous outbreaks of Andes virus disease marked by limited person-to-person transmission. The virus is found in Argentina and Chile. The virus causes hantavirus pulmonary syndrome. Andes virus disease is transmitted through the body fluids of infected rats and also through their bites and scratches. The symptoms include fever, headache and fatigue. In critical cases, respiratory failure may occur. The case fatality rate is put at 40 per cent. 

There is no specific treatment for hantavirus disease. No antiviral drugs or vaccines have been developed yet. Further, early symptoms resemble those of febrile or respiratory illnesses such as influenza, viral pneumonia, dengue or COVID-19. That is why, it is imperative to diagnose the disease through a patient’s case history. Their travel history, occupational and environmental risks and possible contact with rodents and infected cases are equally important in diagnosing the disease.

For lack of specific treatment, supportive care is adopted as medical intervention. Patients are usually kept in an intensive care unit, considering that the disease can escalate into grave conditions such as hantavirus cardiopulmonary syndrome or haemorrhagic fever with renal failure. Such care focuses on close clinical monitoring and management of respiratory, cardiac and renal complications.    

It may be noted that the government has clarified that the threat of hantavirus disease is low in Nepal as the Andes virus has not been found in the country. Still, precautionary measures need to be taken before it is too late. The virus has not been seen in India, either, although the country is favourable for the virus. If the virus enters India, there is a high risk that Nepal will be infected. As such, it would be judicious to take preventive measures. 

The most important thing to protect ourselves from hantavirus disease is to avoid contact with infected rodents. Rodents, especially rats, infest almost every house. Houses and premises should be cleaned to keep rats at bay. Entry points for rats should be properly sealed. Protective gear like masks and gloves should be used when cleaning rat waste. Dry cleaning should be avoided. Vacuum-cleaning rat waste should also be avoided. Floors should be dampened before cleaning. Hand hygiene like washing hands with soap and water or sanitiser should be adopted. Cleaning enclosed or poorly ventilated spaces, working on farms or in forests or sleeping in rat-infested dwellings may increase the risk of hantavirus disease. Should there appear symptoms like fever, respiratory problems or other unusual conditions, medical attention should be sought. 

It may be noted that the ebolavirus outbreak is going on in the Democratic Republic of the Congo and Uganda. The WHO has declared the disease a public health emergency of international concern. Hantavirus disease has not been declared as such as it has not assumed epidemic proportions like those of ebolavirus disease but the risks from the disease should not be downplayed. However, the WHO is working to prevent and control the disease. The world health body is developing and updating evidence-based guidelines on the management of the disease. Further, there are one-health approaches designed to address the interconnectivity between human health, rodent reservoirs and the environment.   

Although hantavirus disease has not entered Nepal, we should not remain complacent. We should always be on the alert. It need not be reiterated that when our country had not been infected with COVID-19 in the first few months of 2020, some leaders openly suggested that international tourists be invited to the country. Thereafter, coronavirus disease infected the country. The disease infected over a million with 12,031 deaths. The effects of the disease are still lingering in our economy. We have not fully bounced back from the effects. We should learn a lesson from the COVID-19 pandemic.  

(Maharjan has been regularly writing on contemporary issues for this daily since 2000.)