Biological and genomic variability among arenaviruses

The arenavirus family contains several distinct viruses with markedly different biological properties. ^1-5 Each virus is associated in the wild with a particular rodent host and is usually found in well-defined geographical regions, i.e., Lassa: West Africa, Junin: Argentina, Machupo: Bolivia. In contrast, lymphocytic choriomeningitis virus (LCMV), the prototype arenavirus, is widely distributed throughout the world (see Table 1). The viruses are maintained in natural rodent populations by both vertical and horizontal transmission. Despite a life-long viremia, the rodents normally show no overt signs of disease except under conditions of extreme crowding or stress. Primary human infection occurs from contact with infected animals or their excreta. Lassa fever transmission in man has occurred via contaminated blood or syringes.