91AV

Guidance for Personnel Working with Wild Rodents at 91AV

What is lymphocytic choriomeningitis?

Lymphocytic choriomeningitis is a disease caused by the lymphocytic choriomeningitis virus (LCMV). LCMV is one of a family of viruses called arenaviruses. Arenaviruses are generally associated with rodent-transmitted disease in humans.

How is LCMV spread?

The rodent hosts of arenaviruses are chronically infected with the viruses; however, the viruses do not appear to cause obvious illness in them. LCMV appears to be passed from mother rodents to their offspring during pregnancy, and thus remain in the population generation after generation. Human infection with arenaviruses is incidental to the natural cycle of the viruses and occurs when an individual comes into contact with the excretions or materials contaminated with the excretions of an infected rodent, such as ingestion of contaminated food, or by direct contact of abraded or broken skin with rodent excrement. Infection can also occur by inhalation of tiny particles soiled with rodent urine or saliva (aerosol transmission). Some Human LCMV infection depends upon factors such as the prevalence of infected animals in a population and close contact with them.

Who is at risk for infection?

The types of incidental contact depend on the habits of both humans and rodents. Where the infected rodent species prefers a field habitat, the risk of human infection is associated with agricultural work. In areas where the rodent species habitat includes human homes or other buildings, infection occurs in domestic settings. Pregnant women who are exposed to LCMV have a high risk of fetal transmission of LCMV.

Is LCMV infection serious?

LCMV causes aseptic (non-bacterial) meningitis. A number of arenaviruses cause hemorrhagic fever. The clinical spectrum of acquired human LCMV infection ranges from inapparent and asymptomatic to, in rare, instances, severely symptomatic, systemic, and fatal central nervous system (CNS) disease. Additionally, pregnancy-related infection has been associated with congenital hydrocephalus, chorioretinitis and mental retardation.

How can I protect myself?

• LCMV in humans can be prevented by limiting contact with blood urine or feces of potentially infected animals.
• The use of personal protective clothing, secondary containment and engineering controls when handling potentially infected animals.
• Workers in potentially high-risk settings, such as rural field research, should receive a thorough orientation about LCMV transmission and the symptoms of the disease.
• Workers who develop febrile or respiratory illness within 45 days of potential exposure should immediately seek medical attention.
• LCMV is susceptible to most disinfectants dilute hypochlorite solutions (bleach), 70% ethanol, detergents, phenolics, or most general household disinfectants.
• Workers should wear rubber, plastic, or latex gloves when handling rodents, cages, or traps contaminated by rodents or whenever the worker has broken skin. Before removing the gloves, wash gloved hands in a disinfectant and then in soap and water. Thoroughly wash hands with soap and water after removing gloves. If this is not possible, then rinse gloves with water or use a disinfectant wipe; wash hands thoroughly at the end of the work period.
• Women who are pregnant should avoid contact with wild rodents.

What are the signs of LCMV infection?

Typical LCMV infection in adults is a biphasic disease with fever, malaise, myalgias, anorexia, nausea, vomiting, pharyngitis, cough, and adenopathy followed by defervescence and a second phase of CNS disease. However, CNS symptoms may appear without any prodrome or may never develop. Meningitis and meningoencephalitis are the most frequent neurologic manifestations of disease.

 What do I do if an exposure or injury occurs?

Exposure to aerosols, bites or scratches involving animals or injuries from objects contaminated with body fluids from animals require immediate first aid and medical attention. Notify your supervisor! Then, contact the University Police Department at 593-2611 or dial 911.