10,000 tourists who spent the night in Yosemite National Park in California during the summer of 2012 are at risk of contracting the life-threatening hantavirus. Up to September 1, 2012, six infections have already been diagnosed and two patients have not survived the virus. The hantavirus has been identified in the tent houses located in Curry Village, a camping area within Yosemite National Park. Anyone who spent the night here between June 10 and August 24, 2012 runs the risk of being infected with this life-threatening virus.

Hantavirus

Hantaviruses are single-stranded RNA (ribonucleic acid) viruses and belong to the bunyavirus family. Other known RNA viruses are influenza (flu), polio, hepatitis C, SARS and West Nile fever.Bunyaviruses generally occur in arthropods and rodents, but some viruses from this family can also infect plants and/or humans. These viruses are transmitted by vectors. With the exception of hantaviruses, bunyaviruses are transmitted via an arthropod vector such as the mosquito, tick or sandfly. These viruses occur most often in the summer.Hantaviruses are transmitted by various species of rodents. The transmission of this virus mainly takes place through inhalation of airborne virus particles that come from rodents . The greatest risk of infection is in closed spaces such as tents and houses. Contact with saliva and feces (vomit, urine and feces) of rodents can also cause infection. The hantavirus is not contagious in the sense of human-to-human transmission. The symptoms include fever, muscle pain, back pain, abdominal pain, headache, vomiting, diarrhea, bleeding tendency, subcutaneous bleeding, coughing, shortness of breath, fluid in the lungs, lung disorders, severe drop in blood pressure, renal insufficiency, drowsiness and circulatory shock. The incubation period between exposure and the appearance of symptoms is one to six weeks.

Two syndromes

Hantavirus is divided into two syndromes: hemorrhagic fever with renal syndrome and cardiopulmonary syndrome.The symptoms of hemorrhagic fever with renal syndrome are fever, bleeding tendency, low blood pressure and renal insufficiency. The disease course varies from mild to rapidly fatal. This syndrome occurs in Asia and Europe. This includes the Puumala virus, which also occurs in the Netherlands. Symptoms of this virus include fever, abdominal pain, flank pain, nausea, vomiting, headache, conjunctival bleeding and a slow heart rate. The Puumala virus is transmitted by the red vole.Cardiopulmonary syndrome causes symptoms such as a high heart rate and rapid breathing in combination with serious lung disorders. This syndrome occurs in America and is very fatal.

History and diagnostics

The hantavirus was first identified during the Korean War from 1951 to 1953. Among the United Nations military troops at the time, 3,000 people became ill, of which 300 died. Navajo Indians were once infected by the virus while harvesting pine nuts, because they regularly came into contact with cotton rats that carried the life-threatening virus. Other epidemics involving hantavirius have occurred in Panama, Scandinavia and Russia, among others.Serological tests are the most important means of diagnosing hantavirus. These tests look at the interaction of antigens and antibodies. The presence of Immunoglobulin M class bodies or a fourfold increase in Immunoglobulin G in the blood are evidence of recent infection with the virus.

Measures

Hantaviruses occur in many places around the world. The rodents that spread the virus do not get sick themselves and can be contagious for months.Avoid contact with rodents and products they may have contaminated. Also pay close attention during cleaning, because virus particles in rodent feces can be spread through the air and inhaled during cleaning work.Be alert if, after the first symptoms of fever, grogginess and headache, you develop complaints of nausea with vomiting and pain in the abdomen and back three to four days later. Depending on the type of virus, recovery may occur or lung or kidney disorders may develop.To date, no drug has been invented against the hantavirus and 38% of patients infected with the virus die. However, in certain cases of illness, perhaps less serious cases, it is thought that timely administration of ribavirin and supportive measures such as restoring blood pressure and kidney function have had a positive effect.

Hantavirus in the United States during the 2012 summer season

Between 1993 and 2001, 587 people in the United States were infected with the hantavirus, of which a third of the patients did not survive the virus. In the summer of 2012, hantavirus infection may have occurred in California’s Yosemite National Park between June 10 and August 24 . The precise location where the virus has been identified is in the tent houses (pre-set up tents) of the Curry Village camping area located in the park. The few hundred tents are spread throughout the forest. The hantavirus is transmitted by the deer mouse; 20% of these mice living in Yosemite National Park are carriers of the virus.The authorities have now informed 2,900 people about their possible infection with the hantavirus. About four million tourists stay in the park every year. Between June 10 and August 24, 2012, this was 10,000. Of the cases of illness diagnosed up to September 1, 2012, four out of six patients survived the virus.