A hemorrhagic fever
caused by the Junin RNA virus
and transmitted by contact with the excreta of vesper mice (Calomys musculinus or C.
laucha). The virus
is deposited into maize
farmers’ homes in urine when the rodents’ natural grassland habitat
is cleared and maize
is planted. AHF is a significant disease
in South America. Clearing of the pampas for the exclusive use of maize
planting has expanded the rodents’ range
. The use of herbicides drastically reduced the natural weeds, and this in turn reduced the local snake populations
and favored rodent overpopulation.