Hantaviruses are a family of viruses spread mainly by rodents and can cause varied disease syndromes in people worldwide.  Infection with any hantavirus can produce hantavirus disease in people. Hantaviruses in the Americas are known as “New World” hantaviruses and may cause hantavirus pulmonary syndrome (HPS). Other hantaviruses, known as “Old World” hantaviruses, are found mostly in Europe and Asia and may cause hemorrhagic fever with renal syndrome (HFRS). Hantavirus is a virus that is found in the urine, saliva, or droppings of infected deer mice and some other wild rodents (rat, hamster, mouse, cotton rats, rice rats etc).

It causes a rare but serious lung disease called Hantavirus pulmonary syndrome (HPS). The virus does not remain active for long once outside of its host — less than 1 week outdoors and a few hours when exposed to direct sunlight. The most common way people are infected with HPS is when they breathe in particles of the waste left by infected mice. When fresh rodent urine, droppings, or nesting materials are stirred up, tiny droplets containing the virus get into the air.

This means that if someone is cleaning out an area infested with diseased mice, like a garage or cabinet, one can stir up particles and become infected within minutes. One can also get hantavirus by touching urine, saliva, or faeces from mice and then touching your mouth. It is very unlikely to be spread from person to person. Hantavirus is usually found in rural areas with forests and fields where mice can live.

The disease caused by Hantavirus is called Hantavirus pulmonary syndrome (HPS). Symptoms appear within 1 to 5 weeks after exposure. The average is 2 to 4 weeks. This disease is extremely serious since about 40% of the people who get the disease die. The disease begins as a flu-like illness. In the early stage, a worker may experience fever, chills, muscle aches, headaches, nausea, vomiting, and shortness of breath, rapid heartbeat and gastrointestinal problems. However, the disease progresses rapidly and infected people experience an abnormal fall in blood pressure and their lungs will fill with fluid. Severe respiratory failure, resulting in death, can occur within a few days of the early-stage symptoms.

Hantavirus pulmonary syndrome can quickly become life-threatening. As the lungs fill with fluid, breathing becomes more and more difficult. Blood pressure drops and organs begin to fail, particularly the heart. Depending on the hantavirus strain, the mortality rate for the North American variety of hantavirus pulmonary syndrome can be more than 30%.

There is no specific vaccine, treatment or cure for Hantavirus infection but early recognition and medical care in an intensive care unit can help with recovery. Infected people may be given medication for fever and pain and oxygen therapy. Avoidance of virus-contaminated dust during work or leisure time is of prime importance; for people with underlying disease, face masks could be used. Creation of air-borne dust should be avoided when areas containing rodent droppings are cleaned, and moist cleaning with disinfectants is recommended. Wild rodents taken into homes as pets or to laboratories for research purposes have caused infections.

The treatment of hantavirus disease is mainly symptomatic. Maintaining the fluid balance, while avoiding over-hydration in a potentially oliguric patient is of critical importance. In case of renal insufficiency, dialysis may be required. Because European hantaviruses do not spread from human to human, no isolation is needed.

Following are the attempts to reduce the presence of mice and limit contact with their droppings, urine and saliva by:

  • Storing food (including pet food), water and garbage in heavy plastic or metal containers with tight-fitting lids.
  • Sealing any holes in structures where mice may enter.
  • Cutting back thick brush and keep the grass short. Keep woodpiles away from the building.
  • Using a rubber or plastic gloves when cleaning up signs of rodents, handling dead rodents, or other materials.  When finished, clean gloves with soapy water before taking them off. Wash hands with soapy water (again) after removing the gloves.
  • Setting traps when necessary.  Put rodents in a plastic bag, seal the bag, and dispose of.

Since the human infection occurs through inhalation of contaminated material, clean-up procedures must be performed in a way that limits the amount of airborne dust. Treat all mice and droppings as being potentially infected. People involved in general clean-up activities where there is not the heavy accumulation of droppings should wear disposable protective clothing and gloves (neoprene, nitrile or latex-free), rubber boots and a disposable N95 respirator. For cleaning up rodent contaminated areas with heavy accumulations of droppings it is necessary to use powered air-purifying (PARP) or air-supplied respirators with P100 filters and eye or face protection to avoid contact with any aerosols.

Dead mice, nests and droppings should be soaked thoroughly with a 1:10 solution of sodium hypochlorite (household bleach). Bleach kills the virus and reduces the chance of further transmission. The contaminated material should be placed in a plastic bag and sealed for disposal. Disinfect by wet-wiping all reusable respirator surfaces, gloves, rubber boots and goggles with bleach solution. All disposable protective clothing, gloves and respirators should be placed in plastic bags and sealed for disposal. Please contact your local environmental authorities concerning approved disposal methods.

Submitted by “Maham Zia”