Lymphocytic choriomeningitis virus (LCMV) is a viral disease primarily carried by rodents, with the common house mouse (Mus musculus) being its natural host. Understanding how long LCMV can survive on inanimate surfaces is important for preventing its spread to humans. Humans can acquire LCMV through contact with contaminated rodent excretions and secretions, such as urine, droppings, or saliva. This highlights the importance of surface hygiene in areas where rodents may be present.
How Long LCMV Persists on Surfaces
LCMV is generally not highly stable when outside a host, and it can be quickly inactivated under typical environmental conditions unless preserved at very low temperatures, specifically around -80°C. Despite this, the virus can maintain its infectivity for at least 206 days when stored in specific laboratory solutions, such as 50% glycerine and 0.85% saline, at colder temperatures ranging from 4-10°C. In natural environments, the virus typically remains infectious for only a few days.
The presence of organic matter, such as rodent droppings and urine, plays a significant role in protecting the virus, allowing it to persist longer on surfaces. While the virus is sensitive to certain conditions, it shows some resistance to drying when contained within these biological materials. This characteristic allows for the possibility of transmission through the inhalation of aerosolized viral particles from dried rodent excretions, such as dust containing urine or feces. Studies have shown a substantial reduction in viral infectivity within mouse droppings over several hours.
Environmental Factors Affecting LCMV Survival
The viability of LCMV on surfaces is significantly influenced by various environmental conditions. Temperature is a major factor, with the virus being heat-labile and inactivated by exposure to elevated temperatures, specifically 55°C for at least 20 minutes.
Exposure to ultraviolet (UV) light also effectively inactivates LCMV. The acidity or alkalinity of the environment also impacts survival, as the virus loses infectivity rapidly at pH levels below 5.5 and above 8.5.
Reducing Risk from Contaminated Surfaces
To mitigate the risk of LCMV transmission from contaminated surfaces, certain cleaning and hygiene practices are important. It is important to avoid disturbing dust in areas where rodents may have been present, as this can aerosolize viral particles; therefore, sweeping or vacuuming should be avoided initially. Instead, contaminated areas should first be thoroughly wetted with a suitable disinfectant.
Effective disinfectants against LCMV include solutions of 10% bleach (sodium hypochlorite), 70% ethanol, and other common household disinfectants. A common bleach solution for this purpose can be prepared by mixing 1½ cups of household bleach per gallon of water. Disinfectants should be allowed sufficient contact time, typically around 30 minutes, before cleanup to ensure inactivation of the virus.
Personal hygiene practices are also important. Individuals should wear rubber, latex, vinyl, or nitrile gloves when cleaning areas potentially contaminated by rodents. Thorough handwashing with soap and water is important after handling rodents, their cages, or bedding, even after removing gloves. If soap and water are not available and hands are not visibly soiled, an alcohol-based hand rub can be used.