There is evidence that cases of Lassa fever increase during the dry season, and ecology studies suggest this is because of a restriction of food supply outdoors. However, this rise may not exclusively be related to rodent movement. For instance, this might be related to increased survivability of the virus in lower temperatures, or increases in pre-existing rodent populations within households. However, previous studies have failed to show a correlation between the abundance of infected rodents in houses and the incidence of human Lassa fever cases. Lassa virus was only significantly associated with seasonality amongst rodents trapped in proximal fields. For those trapped insides homes, whilst the population of the rodents had increased, the virus prevalence fluctuated non-significantly.
