Detection of coccidioidal antibodies in serum of a small rodent community in Baja California, Mexico

• We examine exposure of rodents to Coccidioides spp.
• Coccidioidal antibodies detected in serum of Deer mice and woodrats.
• Gaining information on the ecological niche of Coccidioides spp.
• Molecular environmental detection of Coccidioides spp.

Coccidioidomycosis (Valley Fever) represents a serious threat to inhabitants of endemic areas of North America. Despite successful clinical isolations of the fungal etiological agent, Coccidioides spp., the screening of environmental samples has had low effectiveness, mainly because of the poor characterization of Coccidioides ecological niche. We explored Valle de las Palmas, Baja California, Mexico, a highly endemic area near the U.S.–Mexico border, where we previously detected Coccidioides via culture-independent molecular methods. By testing the serum from 40-trapped rodents with ELISA, we detected antibodies against Coccidioides in two species: Peromyscus maniculatus and Neotoma lepida. This study comprises the first report of wild rodent serum tested for coccidioidal antibodies, and sets the basis to analyze this pathogen in its natural environment and explore its potential ecological niche.