Lymphocytic Choriomeningitis Virus (LCMV) Infection

Updated: Sep 11, 2017
  • Author: Philip J McDonald, MD; Chief Editor: Burke A Cunha, MD  more...
  • Print
Overview

Background

Lymphocytic choriomeningitis virus (LCMV) was first isolated in 1933 from a patient suspected to have St. Louis Encephalitis. [1] It is a single-stranded RNA virus that belongs to the family Arenaviridae (so named because of their appearance on electron microscopy, which, owing to host ribosomes, resemble grains of sand). [2]

Other members of the Arenaviridae family include the Lassa virus (LASV) and the New World complex viruses (Junin, Machupo, Guanarito, Sabia). Infection with LCMV results in a febrile, self-limited, biphasic disease that is often complicated by aseptic meningitis. Infected but asymptomatic (carrier state) rodents, most commonly mice (Mus domesticus, Mus musculus), hamsters, and Guinea pigs, serve as reservoirs for LCMV. [3, 4]

LCMV is most commonly transmitted via inhalation of infected excreta. Direct contact and animal bites are a potential route of LCMV infection in pet handlers and laboratory technicians. [4, 5]

Next:

Pathophysiology

The initial viremia of LCMV infection (phase 1) extensively seeds extra-CNS tissue. The secondary viremia (phase 2) infects the meninges and, less commonly, the cortical tissue. The leptomeninges are infiltrated mainly by lymphocytes and histiocytes, with few neutrophils. In LCMV encephalitis, the same type of inflammatory cells is observed in the perivascular Virchow-Robin spaces. LCMV is not cytotoxic. It appears that the host's immune response to the infected cells produces the various manifestations of this disease. Natural killer (NK) cells are first to respond, followed by the production of interferon by cytotoxic T cells. LCMV antibodies become detectable during the second febrile episode. In addition, LCMV can suppress the production of acetylcholine neuronal cells in cell culture. [6, 7, 8, 9, 10]

LCMV may affect the autonomic nervous system, various sensory modalities, and cranial nerves. Rarely, the virus can cause long-term neurologic sequelae, including chronic headache, hydrocephalus, deafness, transverse myelitis, and Guillain-Barré syndrome. [11] Other organs, especially the testes, heart, and joints, may be involved. Orchitis is usually unilateral and develops 1-3 weeks after illness onset. Cardiac involvement can occur in the form of viral myocarditis or pericarditis. The metacarpophalangeal joint and the proximal interphalangeal joint are the most common sites of arthritis caused by LCMV. The objective swelling, redness, and pain resolve within a few weeks. [8, 9, 12]

Vertical transmission of LCMV during pregnancy has been associated with increased risk of spontaneous abortion. It can also cause a syndrome of hydrocephalus, chorioretinitis, and perivascular calcifications similar to that seen in congenital cytomegalovirus (CMV) infection and toxoplasmosis, potentially leading to mental retardation, microcephaly, seizures, and blindness. [13]

In solid organ transplant recipients with donor-derived infection (DDI), LCMV has been shown to cause severe illness characterized by multisystem organ failure. [14] Meningitis is a less-prominent feature in these individuals. Their high degree of morbidity and mortality can be attributed to profoundly decreased cell-mediated immunity due to immunosuppression.

Previous
Next:

Epidemiology

Frequency

United States

The exact incidence of LCMV infection is unknown, although the seroprevalence is approximately 5%. Local variations in seropositivity for LCMV (2%-5%) depend on the local rodent populations. [15] The true prevalence of LCMV infection is suspected to be higher because of underreporting and missed diagnoses; 10% or more cases of aseptic meningitis may be due to LCMV. [16] LCMV infection in humans is most common in autumn owing to migration of mice into warm structures. [9]

International

LCMV infections have been reported in North America, South America, Europe, Australia, and Japan. [9, 17, 18]

Mortality/Morbidity

LCMV infection carries a mortality rate of less than 1%. Death may be attributable to complications of encephalitis or to a hemorrhagic syndrome. As with other arenaviruses, immunosuppression may predispose to a syndrome of multisystem organ failure including hemorrhage. [16]

Race

LCMV infection has no racial predilection.

Sex

LCMV infection has no sexual predilection.

Age

LCMV infection is more common in young adults, although illness may occur in any age group. [9]

Previous