Cryptosporidium, Microsporidia and Giardia infections in endangered mountain gorillas inhabiting Virunga Massif

The number of mountain gorillas (Gorilla beringei beringei) has grown steadily in recent decades thanks to intensive conservation efforts. But as they live in restricted areas, they experience changes in population dynamics and pathogen epidemiology. These changes have been demonstrated by the emergence of gastrointestinal problems linked to strongylid infections in the Virunga population, highlighting the need to study changes in other parasite infections. We assessed the patterns of Cryptosporidium, Giardia and microsporidia infections in mountain gorillas across the Virunga Massif. We examined 152 faecal samples from 16 gorilla groups collected in 2018 using PCR and qPCR on three genetic markers and detected Cryptosporidium muris (< 1%), Enterocytozoon bieneusi (genotypes-D 14%, CHN-F1 < 1%) and Giardia intestinalis (13%). No significant spatial or sex/age differences were observed in microsporidia and Giardia infections. However, a temporal comparison with previous data suggests changes in the protist communities over time. We conclude that these protists were not impacted by the changes in mountain gorilla population dynamics and did not contribute to the increasing occurrence of severe gastrointestinal problems in Virunga gorillas. These results aid our epidemiological understanding of parasite communities in mountain gorillas, an asset for their ongoing conservation management in the face of newly emerging health challenges.