The Michigan Department of Community Health (MDCH) today issued a public health order restricting the sale of several species of rodents shipped from an Ohio distribution facility after receiving information that animals sold since February could be infected with a disease that can cause serious complications for unborn children and people with weakened immune systems.

Click here for a copy of the order.

The stop-sale order was issued August 8 after the Centers for Disease Control and Prevention (CDC) advised 22 states and the District of Columbia that rodents infected with lymphocytic choriomeningitis virus (LCMV) were disseminated from Mid-South Distributors Ohio facility to pet stores throughout the country earlier this year. The order prohibits the sale of these animals statewide from pet stores that received animals from this distributor.

"While we believe the risk in general to Michigan citizens to be low, we are issuing this order because we believe the public health to be at-risk for certain populations – most notably pregnant women and people with compromised immune systems," said Dr. Dean Sienko, acting State Chief Medical Executive. "Our primary goal is to protect those vulnerable citizens that may have come in contact with infected rodents."

LCMV infection in humans is uncommon. At this time, Michigan has no evidence that any person in the state has contracted this illness, Sienko said.

The order – which will be lifted after public health officials determine that no risk remains – prohibits all intra-state transportation, display, sale, distribution, or release of animals into the environment of some members of the order Rodentia, including hamsters, dwarf hamsters, guinea pigs, and mice.

The order also covers rodents sharing cages with the potentially infected animals, and any rodents that shared contaminated articles, such as water bottles, food, bedding, and toys.

"We will work with regulated pet stores around the state to ensure compliance with this order," said Mitch Irwin, Director of the Michigan Department of Agriculture. "We are sensitive to the fact that this order may potentially impact the retail pet store trade, and want to resolve this situation as quickly as possible."

Before resuming the display, sale, or distribution of rodents, the order also requires pet stores that received animals from the Mid-South facility to clean and disinfect all rodent holding facilities, and to take steps to ensure that future cross contamination does not occur, Irwin said.

LCMV infection during the first or second trimester of pregnancy can cause severe illness or developmental defects in unborn children, including hydrocephalus, psychomotor retardation, and blindness. Others at-risk from this illness include people with compromised immune systems.

In May 2005, CDC received reports of illness in four solid organ-transplant recipients who were later diagnosed with LCMV infection from a common organ donor who had been in contact with an infected hamster. Three of the four organ recipients died 23 to 27 days after transplantation.

LCMV testing of other rodents at the pet store where the animals were sold in Rhode Island revealed three other LCMV-infected rodents (two hamsters and a guinea pig), which had, like the organ donor’s pet, been supplied by a single distributor, Mid-South Distributors in Ohio.

On the basis of a comparison of LCMV test results in the sampled rodents and records reviewed at the Rhode Island pet store and Ohio Mid-South facility, it is likely that LCMV-infected pet rodents have been distributed from the Ohio Mid-South facility to pet stores in the Northeast and Midwest United States, including Michigan, beginning as early as February 2005.

LCMV is not normally found in pet rodents, such as hamsters, gerbils, and guinea pigs. However, pet rodents can become infected if they have contact with wild house mice in, for example, the breeding facility, the pet store, or the home.

Efforts are underway by the Michigan Department of Agriculture to ensure that animal facilities and equipment in retail outlets are disinfected, that new supplies of rodents come from sources that are free of LCMV, and that cross contamination between new supplies of rodents and potentially infected animals will not occur.

LCMV infection can be prevented by avoiding contact with house mice and by taking precautions when handling pet rodents (i.e., mice, hamsters, or guinea pigs). If you have a pet rodent, take the following precautions to reduce the risk of LCMV infection:

• Wash hands with soap and water after handling pet rodents; use waterless alcohol-based hand rubs when soap is not available.
• Keep rodent cages clean and free of soiled bedding.
• Clean the cage in a well-ventilated area or outside
• Wash hands thoroughly with soap and water after cleaning up pet droppings. Closely supervise young children, especially those less than five years old, when cleaning cages, and make sure they wash their hands immediately after handling rodents and rodent caging or bedding.
• Do not kiss pet rodents or hold them close to your face.

Under Michigan’s Public Health Code, Sienko – as acting state Chief Medical Executive – is granted broad statutory authority to safeguard Michigan citizens if he believes the public health to be at risk.