Hantaviruses constitute a genus (Orthohantavirus) of enveloped viruses of the order Bunyavirales.

All hantaviruses of medical significance are carried by rodents of the families Muridae and Cricetidae. They are linked with two severe acute febrile illnesses: Hemorrhagic fever with renal syndrome (HFRS), caused by hantaviruses of the Old World; and Hantavirus cardiopulmonary syndrome (HCPS), caused by hantaviruses of the New World), also termed hantavirus pulmonary syndrome (HPS).

The carrier and source of transmission for both are wild rodents.

People get infected through aerosols of rodent excreta, especially in closed buildings with poor ventilation, or while cleaning.

China has the highest incidence of hantavirus disease per year. Nearly 16,000 to over 100,000 cases of HFRS are reported annually in China. Thousands of cases are likely reported in Russia. On the contrary, only 728 cases of HCPS have been noted in the United States. Clinical episodes of hantavirus disease are also reported in other parts of the world, including Europe and South America.

Case-fatality ratios depend on the species of the virus. In some parts of the world, considerable numbers of asymptomatic or subclinical infections have been noted while in other regions, it becomes difficult to find those who have been exposed without a history of disease.

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA