The vector is the "Calomys callosus" (large vesper mouse), a rodent indigenous to northern Bolivia. Its vector is the drylands vesper mouse, a rodent found in Argentina and Paraguay. The small vesper mouse ("Calomys laucha") is a rodent species from South America. The fecund vesper mouse ("Calomys fecundus") is a species of rodent in the family Cricetidae. The Peruvian vesper mouse ("Calomys sorellus") is a species of rodent in the family Cricetidae. The Bolivian vesper mouse ("Calomys boliviae") is a species of rodent in the family Cricetidae. The drylands vesper mouse ("Calomys musculinus") is a species of rodent in the family Cricetidae. The crafty vesper mouse ("Calomys callidus") is a species of rodent in the family Cricetidae. Hummelinck's vesper mouse ("Calomys hummelincki") is a species of rodent in the family Cricetidae. The Andean vesper mouse ("Calomys lepidus") is a species of rodent in the family Cricetidae.