Hantavirus is a life threatening disease carried by rodents which is rare in the UK. In the past 30 years, there have been around 40 cases of hantavirus confirmed in the UK, mostly linked to an outbreak in Somerset in 1992.
But it now looks like hantavirus is back. Last week The Telegraph reported that rats carrying the disease have arrived in Yorkshire and The Humber on trade ships from Asia. Scientists have confirmed that a man in North Yorkshire was diagnosed with the disease and suffered severe kidney problems, though has since recovered. Health experts trapped a number of rodents at his farm and house which were later found to be carrying the same strain of the disease. Eurosurveillance detailed how eleven rodents were analysed for the presence of hantavirus RNA: five Apodemus sylvaticus (wood mouse), four Rattus norvegicus (Norway rat) and two Myodes glareolus (bank vole).
Transmission of the virus between rodents and to humans occurs through inhalation of dust infected with rodent excreta and urine, or a rodent bite. Once infected the rodent will secrete infectious virus for prolonged periods, probably for life. Those working with wood piles and or cleaning abandoned buildings can be at a risk of contracting hantavirus. Campers too are at risk. Last year there were six cases of hantavirus at Yosemite National Park , including two fatalities. The casualties were staying in log cabins which had been infested by mice.
Because of the lag of time in which the symptoms appear hantavirus can be difficult to detect. In the US there has been almost 600 cases since 1993; about one in three proved fatal. It wasn’t until 1993 that the Centers For Disease, Control and Infection linked two deaths of healthy men to deer mice. A cluster of cases in the southwest known as The Four Corners area launched an investigation. There had been in a drought in the region for several years. Then, in early 1993, heavy snows and rainfall caused plants and subsequently, the rodent population to flourish. The area’s deer mice reproduced so rapidly that there were ten times more mice in May 1993 than there had been in May of 1992. With so many mice, it was more likely that mice and humans would come into contact with one another, and thus more likely that the hantavirus carried by the mice would be transmitted to humans.
Early symptoms are similar to flu and include chills, fever and muscle aches and can take up to five weeks to develop after exposure. People with hantavirus may begin to feel better for a very short amount of time, but within 1-2 days, symptoms can once again reappear with a dry cough, headache, nausea and shortness of breath. Complications of hantavirus can lead to acute respiratory distress syndrome, kidney failure and heart and lung failure.
The possibility of exposure amongst campers, hikers and tourists to endemic areas is generally considered to be low, and can be reduced if rodent contact is avoided. However, please call your doctor immediately if you develop flu-like symptoms after you come in contact with rodent droppings or rodent urine.