recommend vigilant screening laboratory animals to be used in research facilities either through serum samples or cell line aliquots, as well as ensuring adequate ventilation in housing areas and use of appropriate sanitation products. Other practices to reduce cross-contamination in rodents include washing hands or changing gloves between animal care activities, thoroughly decontaminating cages before reusing them, and avoiding housing healthy rodents in the vicinity of potentially infected rodents. Other animals
Although the house mouse (Mus musculus) is the primary reservoir host for LCMV, it is also often found in the wood mouse (Apodemus sylvaticus) and the yellow-necked mouse (Apodemus flavicollis). Hamster populations can act as reservoir hosts. Other rodents including guinea pigs, rats and chinchillas can be infected but do not appear to maintain the virus. LCMV has been shown to cause illness in New World primates such as macaques, marmosets and tamarins. Infections have also been reported in rabbits, dogs and pigs. After experimental inoculation, the incubation period in adult mice is 5 to 6 days. Congenitally or neonatally infected mice and hamsters do not become symptomatic for several months or longer. Mice
A study conducted by John Hotchin and Heribert Weigand, of the New York State Department of Health, concluded, "The age of the mouse when first exposed to the virus determines its immune response." If LCMV infection occurs in utero or within the first few hours of life, during the immunologically unresponsive period, the mouse will develop immune tolerance. The virus will continue to proliferate for an indefinite time.
During the second phase, typical findings include elevated protein levels, increased leukocyte count, or a decrease in glucose levels of the cerebrospinal fluid).Occasionally, a patient improves for a few days, then relapses with aseptic meningitis, or very rarely, meningoencephalitis. Patients with meningitis may have a stiff neck, fever, headache, myalgia, nausea and malaise. In some occasions, meningitis occurs without a prodromal syndrome. Meningoencephalitis is characterized by more profound neurological signs such as confusion, drowsiness, sensory abnormalities and motor signs. Under reported complications include myelitis, Guillain–Barré-type syndrome, cranial nerve palsies, transient or permanent hydrocephalus, sensorineural hearing loss, orchitis, arthritis and parotitis. LCMV infections have also been associated with pancreatitis, pneumonitis, myocarditis and pericarditis. The entire illness usually lasts 1 to 3 weeks, nonetheless, temporary or permanent neurological damage is possible in all central nervous system infections, especially in cases of meningoencephalitis. Chronic infections have not been reported in humans and deaths rarely occur. Cause
Virus biology
There are several strains of LCM virus, among which the most widely used are LCMV Armstrong and LCMV Clone 13. Armstrong is the original virus strain which was isolated from the brain by Charles Armstrong in 1934. It triggers a vigorous cytotoxic T lymphocytes(CTL) response and thus, it is cleared rapidly by the host. This is referred to as acute (Armstrong) LCMV infection. On the other hand, Clone 13 is a variant of the Armstrong viral strain, isolated from the spleen and is consequently tropic for visceral organs. It was first isolated from mice which sustained a persistent LCMV infection from birth.