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Information for Pet Owners: Reducing the Risk of Becoming Infected with LCMV from Pet Rodents

Where does the LCMV virus come from?

Humans can develop LCMV infection from exposure to urine, droppings, saliva, or nesting material of infected rodents. LCMV infection can also occur when these materials are inhaled or directly introduced into broken skin or into the nose, eyes, or mouth, and possibly by a bite from an infected animal.

What are the symptoms of LCMV in people?

Adults with normal immune systems can be infected with LCMV without symptoms, or they may develop a mild illness with symptoms that may include the following: fever, lack of appetite, muscle aches, headache, chills, nausea, and vomiting. Some people may have meningitis (inflammation of the brain covering) approximately 7-15 days after the start of fever. People with weakened immune systems may have more severe or fatal illness when infected with LCMV.

Women who become infected with LCMV during pregnancy may have spontaneous abortion, or their baby may have severe birth defects, including congenital hydrocephalus (fluid on the brain), chorioretinitis (inflammation of the eye), blindness, or mental retardation. The proportion of developmental defects caused by LCMV is not known.

Can LCMV spread from one person to another?

A pregnant woman who becomes infected can pass the LCMV infection to her unborn baby; in addition, LCMV can be spread through organs transplanted from an infected donor. With the exception of these situations, there is no documented evidence of person-to-person transmission.

Which pet stores have LCMV-infected rodents?

Rodents (including feeder mice) and other pets from any pet store pose some risk of transmitting certain infectious diseases and should be handled appropriately. For more information on how to reduce the risk of infectious diseases from your pet or rodent, please see the CDC Healthy Pets website.

Should I get rid of my pet mouse, hamster or other rodent?

Persons who are not pregnant and who have healthy immune systems are at very low risk for any serious illness associated with LCMV. The probability of any one rodent being infected is low. The greatest risk of infection for a pet or feeder owner is likely to occur soon after purchase of a pet or feeder rodent. Thus, most exposures have likely already occurred for existing owners, and continued ownership of the rodent will not likely result in substantial added risk. Persons with further concerns about their pets or feeder rodents should seek guidance from a veterinarian. Women who are pregnant or planning to become pregnant, or persons who have impaired immune systems should not obtain rodents for pets.

What should I do if I no longer want my pet or feeder rodent?

People who have already purchased mice, hamsters or other rodents from pet stores should not return their animals to the stores, regardless of where the animal was purchased. People who no longer wish to keep their pet or feeder rodent should consult a veterinarian.

Can I release my pet or feeder rodent into the wild?

No. Pet and feeder rodents must not be released into the wild for humane reasons and because it is illegal in many states. Pet and feeder rodents are not adapted to surviving in the wild environment and may starve or be killed by predators. Many pet and feeder rodents are not native species to North America. Releasing them into the wild could introduce a non-native species that could become a pest, endanger native species, or otherwise damage the normal ecosystem.

Can I have my pet or feeder rodent tested for LCMV?

CDC does not recommend testing individual pet and feeder rodents. Testing on live rodents can be inaccurate and misleading. Always assume that pet or feeder animals are capable of transmitting certain infectious diseases. Follow appropriate precautions as described on CDC's Healthy Pets website when handling any pets.

How can I purchase a safe and healthy pet or feeder rodent?

There is no way to be absolutely sure that any pet or feeder animals are free of all infectious diseases. Information on purchasing a healthy pet or feeder rodent and general steps to prevent pet and feeder rodents from bringing diseases into the home is available at

Should pregnant women be concerned about owning a hamster or other rodent?

LCMV infection during pregnancy can cause severe illness or developmental defects in the fetus. Women who are pregnant or who are planning to become pregnant should avoid contact with all rodents. Some of the following precautions can be taken to reduce the risk of acquiring LCMV infection during pregnancy:

  • To avoid contact with wild rodents, pregnant women who reside in a household with a wild rodent infestation should have the infestation controlled promptly by a professional pest control company or another member of the household.
  • To avoid contact with pet or feeder rodents, remove the pet or feeder rodent from the house or keep pet and feeder rodents in a separate part of the home. Pregnant women should ask another family member or friend to clean the cage and care for the pet or feeder rodent or arrange for temporary adoption of the pet or feeder rodent by a responsible person. Pregnant women should avoid any room where a rodent resides.

Should people with weakened immune systems be concerned about owning a hamster or other rodent?

People with an impaired immune system may be at risk for more severe disease from LCMV and other diseases carried by pet or feeder rodents. Persons with an impaired immune system should avoid contact with all rodents.

Can I get tested for LCMV?

Testing for LCMV infection in persons who have no symptoms is not necessary. Individuals who are experiencing symptoms as described above should seek medical care and let the physician know about any exposures to wild, pet or feeder rodents. Only your physician can decide whether testing for LCMV is necessary.

What is being done to prevent LCMV infection in pet and feeder rodents?

CDC and other partners are working with breeders and retailers in the pet industry to minimize the risk of LCMV infection in rodents that are sold to the public and to educate owners of pet and feeder rodents about LCMV infection. For more information on what your state is doing regarding LCMV, please contact your state health department or visit their Web site (

Related Links
 Prevent LCMV from pet rodents
 Prevent LCMV from wild rodents PDF Document Icon [PDF - 95 KB]

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  This page last reviewed August 28, 2012

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