Editor’s note: This article summarizes key points from a Centers for Disease Control and Prevention (CDC) report published in Morbidity and Mortality Weekly Report (MMWR). The Comment section may include information that did not appear in the original publications. To subscribe to MMWR, visit www.cdc.gov/MMWR.
- Talley P, et al. “Notes from the Field: Lymphocytic Choriomeningitis Virus Meningoencephalitis from a Household Rodent Infestation – Minnesota, 2015.” MMWR. 2016;65(9):248-249, http://dx.doi.org/10.15585/mmwr.mm6509a4.
In April 2015, a 15-year-old female presented to her pediatrician with a five-day history of fever, myalgia, photophobia and headache. Her basic laboratory evaluation, including white blood cell (WBC) count and erythrocyte sedimentation rate, was normal and she was provided supportive care.
One week later, she returned with persistent headache, photophobia and new onset of meningismus. She was hospitalized and found to have irritability, hypotension and pancreatitis. Her cerebrospinal fluid revealed pleocytosis (WBC 1,287 cells/uL) with a lymphocytic predominance, low glucose (36 mg/dL) and elevated protein (94 mg/dL).
She was treated empirically for bacterial and herpes simplex virus meningitis. She returned to baseline clinically and was discharged from the hospital on day 11.
Following hospitalization, the Minnesota Department of Health’s Unexplained Critical Illnesses and Deaths Project identified antibodies to lymphocytic choriomeningitis virus (LCMV) by immunofluorescence assay in serum collected on hospital day four. The CDC’s Viral Special Pathogens Branch subsequently performed serologic testing by enzyme-linked immunosorbent assay, which demonstrated an immunoglobulin M titer of >1:6,400, consistent with acute infection.
Mouse fecal pellets from the patient’s home tested positive for LCMV by polymerase chain reaction. The family was referred for integrated pest management services, and no further household cases were reported.
LCMV is a zoonotic arenavirus transmitted to humans by exposure to urine, saliva or other excreta of infected rodents. Clinical manifestations include fever, retro-orbital headache, photophobia, anorexia and nausea. LCMV commonly causes a biphasic illness, with aseptic meningitis or encephalitis occurring in the second phase. Most patients recover without sequelae; however, children younger than 5 years of age, immunocompromised people, pregnant women and adults over 65 years are at increased risk of morbidity and mortality.
Congenital infection with LCMV can cause a spectrum of abnormalities similar to other congenital infections and should be included in the differential diagnosis with these organisms. Treatment primarily is supportive, and no specific antiviral medications are available.
Preventing LCMV infections involves preventing rodent infestations in residences, since approximately 5% of common house mice are chronically infected with LCMV. Through contact with wild rodents, pet rodents can acquire LCMV and become reservoirs of infection within households.
Pediatricians and veterinarians are in unique positions to advise families about infection risks from various organisms associated with nontraditional pets, including rodents (mice, guinea pigs, hamsters), reptiles (turtles, lizards, snakes) and small mammals in the home. Infection risks from these pets are greater in households with children younger than 5 years of age.
Dr. Rostad is a post-graduate training fellow in pediatric infectious diseases at Emory University School of Medicine. Dr. Pickering was editor of the AAP Red Book from 2000-’12. He is adjunct professor of pediatrics at Emory University School of Medicine.