Lymphocytic Choriomeningitis Virus (LCMV)

Frequently Asked Questions

What happened in Rhode Island to bring attention to LCMV?

On April 10 and 11, 2005, four persons in RI and Massachusetts received organ transplants from a common donor. All four patients developed similar complications following surgery. A joint effort was undertaken by the Rhode Island Department of Health, the Massachusetts Department of Public Health, the CDC, the New England Organ Bank and the transplant centers involved. The CDC later confirmed that all the recipients tested positive for lymphocytic choriomeningitis virus (LCMV). Three of the four recipients died due to complications. Although the donor’s death was not related to LCMV and the donor’s blood and tissue did not test positive for LCMV, the donor was probably infected with LCMV from a pet hamster bought three weeks prior to the donor’s death. This is very rare and only the second time transmission of LCMV through organ transplant has ever been seen.

Where does the virus come from?

The primary host is the common house mouse. The virus is found in the saliva, urine, and feces of infected mice. Other types of rodents, such as hamsters and guinea pigs are not the natural reservoirs, but can become infected with LCMV at the breeder, distributor, in the pet store or home environment. Human infections acquired from contact with hamsters have occurred.

How do humans get infected?

Individuals become infected with LCMV after exposure to fresh urine, droppings, saliva, or nesting materials of infected rodents. Person-to-person transmission has not been reported, with the exception of direct transmission from infected mother to fetus or through organ transplantation.

Are some people more at risk than others for contacting LCMV?

Individuals of all ages who come into contact with urine, feces, and saliva of mice, or infected hamsters are potentially at risk for infection. About 5% of the population, when tested, show evidence of prior infection. However, most of these people never show symptoms or signs of illness from the virus.

Owners of pet mice or hamsters may be at risk for infection if these animals come from infected colonies or if the animals become infected from other mice in the home or store.

Laboratory workers and others who handle infected animals are also at risk.

What are the symptoms of LCMV?

Most people with normal immune systems who are exposed to the virus do not become ill. In the few that do show symptoms, these appear 8-13 days after being exposed to the virus. Symptoms are influenza-like, and include fever, stiff neck, malaise, loss or appetite, muscle aches, headache, nausea, and vomiting. Virus is present in the blood and tissues of infected people for the first 7 to 10 days of infection. No person to person transmission of LCMV has been reported.

Is there a test for LCMV in people?

There is no routine test for LCMV. If you are experiencing symptoms, talk to your doctor.

What is the treatment for LCMV?

Most LCMV infections do not cause illness. Rarely, severe infections may require hospitalization, supportive treatment and in extreme circumstances, antiviral medication.

What can I do to prevent getting LCMV?

LCMV infection can be prevented by avoiding contact with house mice and taking precautions when handling pet rodents (i.e. mice, hamsters, or guinea pigs).

If you have a rodent infestation in and around your home, take the following precautions to reduce the risk of LCMV infection:

• Seal up rodent entry holes or gaps with steel wool, lath metal, or caulk.
• Trap rats and mice by using an appropriate snap trap.
• Clean up rodent food sources and nesting sites and take precautions when cleaning rodent-infected areas. See recommendations below for cleaning rodent-infested areas.

Detailed instructions on rodent-proofing the home, safe cleaning practices and trapping wild rodents can be found at www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/lcmv.htm.

What are the precautions for handling pet rodents?

Everyone should take the following precautions when handling pet rodents:

• Hands should be washed with soap and water after handling pet rodents or cleaning up pet droppings, cages, or areas where pets have been. Waterless alcohol-based hand rubs should be used when soap is not available and hands are not visibly soiled.
• Rodent cages should be kept clean and free of soiled bedding.
• Cages should be cleaned in a well-ventilated area or outside (see below for more specific cleaning instructions).
• Young children, for example those less than five years old, should be closely supervised when cleaning cages or handling rodents. They should be supervised or assisted in washing their hands immediately after handling rodents and rodent cages or bedding.
• Pet rodents should never be kissed or held close to the face.
• Pet rodents should not be allowed to come in contact with wild rodents or their droppings or nests. Pet rodent cages and food supplies should be covered. Pet rodents should always be supervised when not in their cages.

Is a hamster or other pet rodent a safe pet for my children? Is a hamster or pet rodent a safe pet for the classroom?

Hamsters and other pet rodents are common and very popular pets with children. The number of human LCMV cases is very low; suggesting that the risk to children can be minimized by taking the above precautions.

What are the recommendations for cleaning a rodent-infested area?

• Use cross-ventilation when entering a previously unventilated enclosed room or dwelling prior to cleanup.
• Put on rubber, latex, vinyl or nitrile gloves.
• Do not stir up dust by vacuuming, sweeping, or any other means.
• Thoroughly wet contaminated areas with a bleach solution or household disinfectant. Hypochlorite (bleach) solution: Mix 1 and ½ cups of household bleach in 1 gallon of water.
• Once everything is wet, take up contaminated materials with damp towel and then mop or sponge the area with bleach solution or household disinfectant.
• Spray dead rodents with disinfectant and then double-bag along with all cleaning materials and throw bag out in an appropriate waste disposal system.
• Remove the gloves and thoroughly wash your hands with soap and water (or waterless alcohol-based hand rubs when soap is not available and hands are not visibly soiled).

In the laboratory environment:

Only animals from sources that regularly test for the virus should be used in the laboratory. Laboratory personnel should wear proper protective laboratory gear and follow appropriate safety precautions.

What should I do if I have a pet rodent that I recently purchased?

There is a very low probability of any animal having LCMV. Rhode Island pet shops recently stopped shipments from the distributor where the virus was found, and the State has stopped any shipments from that distributor indefinitely. The CDC doesn’t recommend destroying or returning any pets. Pet rodents must also not be released into the wild. If you have a specific concern about your pet, you should talk to your veterinarian.

Can I get my pet tested for the virus?

The CDC does not recommend testing pet rodents. Blood testing on rodents can be inaccurate and misleading.

I’m thinking about buying a pet rodent? Are there recommendations to follow?

General steps to prevent pet rodents from bringing diseases into the home can be found at www.cdc.gov/healthypets/lcmv_rodents.htm.

It is unlikely that mice or hamsters will show symptoms of LMCV infection.. When choosing a pet rodent, don’t pick one that is quiet, tired, has diarrhea, or looks sickly. The pet should be lively and alert with a glossy coat free of droppings. The animal’s breathing should be normal. There should be no discharge from the eyes or nose.

If one of the animals in the cage in a pet store has diarrhea or looks sick, the others may have been exposed to an infectious disease. Do not choose any of these animals as your pet. Wash your hands immediately after handling pet store animals or after touching animal cages or bedding.

If your pet dies soon after you buy it, it could have been ill with a disease that could also make people sick. Use gloves when removing the dead rodent from the cage. Then double-bag along with all cleaning materials and throw the bag out in an appropriate trash disposal system. Tell the pet store and do not reuse the cage until it has been cleaned and disinfected.

I am pregnant and own a hamster or other rodent. What should I do?

In general, the risk of LCMV infection from pet rodents is low. However, pregnant women (or women who think they might become pregnant) should be aware and cautious of the risks associated with LCMV infection during pregnancy. The following precautions can be taken to reduce even further the risk of getting LCMV infection during pregnancy:

• Pregnant women should avoid contact with rodents. If you live in a household with a rodent infestation, it should be addressed promptly by a professional pest control company or another member of the household.
• Pet rodents should be kept in a separate part of the home and pregnant women should ask another family member or friend to clean the cage and care for the pet, or temporarily adopt the pet out to a friend or family member. Pregnant women should avoid prolonged stays in the room where a rodent resides.

Why should I be concerned if I’m pregnant?

The risk of LCMV infection is low. LCMV infection during the first or second trimester of pregnancy can cause severe illness or developmental problems in the fetus. As with any illness during pregnancy, you should contact your doctor if you have any symptoms.

I have a weakened immune system. Are there any precautions I should take?

People with impaired immune system function (for example, those with HIV, those undergoing cancer treatment, or organ transplant recipients) should avoid contact with all rodents.

I have a gerbil and a rabbit. Should I be concerned?

Although other animals could possibly become infected with the virus, documented infections in humans have occurred only after exposure to infected mice, guinea pigs, and hamsters.

Our pet hamster just bit my child. What should I do?

The risk of LCMV infection is low. If your child is bitten by any animal, contact your child’s doctor for advice.

I have always cleaned my hamster’s cage without gloves. Will I get LCMV?

The risk for contracting LCMV from rodents is low. Follow the precautions above for handling pets and cleaning cages. If you experience any symptoms, call your doctor.

What is the Rhode Island Department of Health doing?

The Department of Health is working collaboratively with the Department of Environmental Management and CDC to disseminate information to the general public and the medical community on how to prevent exposure to LCMV and other infections passed from rodents.

For more information about LCMV go to: www.HEALTH.ri.gov or to www.cdc.gov. For health-related calls, contact the Family Health Information Line at 1-800-942-7434 from 8:30 a.m. to 4:30 p.m.. For calls about animal-related questions, contact DEM Division of Agriculture at 222-2781 during regular business hours.