Bengaluru: As the world grapples with the coronavirus pandemic, a man in China died of hantavirus earlier this week.
Chinese state-run Global Times reported that a person from Yunnan Province died while on his way back to Shandong Province for work on a chartered bus Monday.
“He was tested positive for #hantavirus. Other 32 people on bus were tested,” it tweeted.
The hantaviruses are a family of viruses that spread in rodents and to humans from rodents.
Some strains of the virus cause fatal illnesses in humans, such as hantavirus pulmonary syndrome (HPS). It is caused by inhalation of excreta particles or aerosols from infected rats.
The family of viruses spreads only from rodents and there is no human to human transmission, except for one virus, the Andes Virus, which spreads between people.
The virus is named after the Hantan River area in South Korea, where one of the early strains of the virus was isolated in the 70s.
Virus structure and evolution
Hantaviruses belong to the order called Bunyavirales and have 12 families.
They were first detected in May 1993 in southwestern United States. They are about a hundredth the size of a bacteria. They are also an RNA virus just like SARS-CoV-2 (the novel coronavirus).
As virions, which are what the virus are called outside of a body or host as independent particles, it consists of RNA, a coat of protein to protect the genetic material, and a fatty outer layer that holds everything in. It is this outer layer that is dissolved by soap, leading to the rest of the virus to disintegrate.
Hantavirus virions are about 150 nanometers in diameter. They attach themselves to cell receptors and then get absorbed into the cell.
Understanding the mechanism of infection has been challenging as hantavirus doesn’t seem to cause the disease in the animals that it infects. There are theories to understand why, including a co-dependent evolutionary relationship, but none have scientific consensus yet.
But the family of viruses do infect rodents across species, and transmission from one species to another has been observed.
There are different kinds of illnesses caused by different hantaviruses, and they affect either the blood vessels or the lungs.
During the fatal hantavirus hemorrhagic fever with renal syndrome (HFRS), the membrane of blood vessels become more permeable and there is a drop in blood pressure.
There is rapid and dramatic damage observed in kidneys during worst forms of the disease. For the other fatal disease, the hantavirus pulmonary syndrome (HPS), there are muscle aches, fever, fatigue accompanied by breathing difficulties later. The most damage is observed in the lung, spleen and gall bladder.
Vaccines developed for the hantavirus have not been so far completely successful for all strains of the virus found in different geographical locations around the world.
But there are a number of vaccine candidates currently undergoing trial. So far, the best protection against contacting hantavirus is to avoid having rodents enter our homes or offices.
The virus is transmitted by rodent excreta, saliva and sometimes, infected rodent bites. Because the virus spreads when excreta or other residue it inhabits rises into the air, the necessary treatment to take is to prevent actions that cause dust to rise and wet down areas with disinfectant.
Hantavirus infections are prevalent all over the world, except for Australia from where no cases have been reported so far. South America sees the highest incidences of cases, followed by North America. In each geographical region, the disease is caused by a different strain of the virus.