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DNA sequence analysis was carried out on Strongyloides spp. larvae obtained from fecal samples of local humans, a wild western lowland gorilla (Gorilla gorilla gorilla) and a central chimpanzee (Pan troglodytes troglodytes) inhabiting Dzanga-Sangha Protected Areas (DSPA), Central African Republic, and eastern chimpanzees (Pan troglodytes schweinfurthii) living in degraded forest fragments on farmland in Bulindi, Uganda. From humans, both Strongyloides fuelleborni and Strongyloides stercoralis were recorded, though the former was predominant. Only S. fuelleborni was present in the great apes in both areas. Phylogenetic analysis of partial mtDNA cytochrome c oxidase subunit 1 gene (Cox1) and comparison of 18S rDNA hyper variable region IV (HVR-IV) sequences implied that in DSPA S. fuelleborni populations in humans differ from those in the nonhuman great apes.

SUMMARYTo address the molecular diversity and occurrence of pathogenic species of the genusEntamoebaspp. in wild non-human primates (NHP) we conducted molecular-phylogenetic analyses onEntamoebafrom wild chimpanzees living in the Issa Valley, Tanzania. We compared the sensitivity of molecular [using a genus-specific polymerase chain reaction (PCR)] and coproscopic detection (merthiolate-iodine-formaldehyde concentration) ofEntamoebaspp. We identifiedEntamoebaspp. in 72 chimpanzee fecal samples (79%) subjected to species-specific PCRs for sixEntamoebaspecies/groups (Entamoeba histolytica, Entamoeba nuttalli, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coliandEntamoeba poleckiST2). We recorded threeEntamoebaspecies:E. coli(47%),E. dispar(16%),Entamoeba hartmanni(51%). Coproscopically, we could only distinguish the cysts of complexE. histolytica/dispar/moshkovskii/nuttalliandE. coli. Molecular prevalence of entamoebas was higher than the prevalence based on the coproscopic examination. Our molecular phylogenies showed that sequences ofE. disparandE. colifrom Issa chimpanzees are closely related to sequences from humans and other NHP from GenBank. The results showed that wild chimpanzees harbourEntamoebaspecies similar to those occurring in humans; however, no pathogenic species were detected. Molecular-phylogenetic methods are critical to improve diagnostics of entamoebas in wild NHP and for determining an accurate prevalence ofEntamoebaspecies.

Background: In general, studies on the diversity of strongylid nematodes in endangered host species are complicated as material obtained by non-invasive sampling methods has limited value for generic and species identification. While egg morphology barely allows assignment to family, the morphology of cultivated infective third stage larvae provides a better resolution at the generic level but cannot be used for exact species identification. Morphology-based taxonomic approaches greatly depend on the examination of adult worms that are usually not available. Methods: Hookworm parasites in two European researchers, who participated in gorilla research in the Central African Republic, were expelled after anthelmintic treatment to the faeces, collected and morphologically examined. A male worm discharged naturally from a wild bonobo (Pan paniscus) in Congo was also examined for comparison. Results: Two species of Necator were identified in researchers' faecal material: Necator americanus (Stiles, 1902) and N. gorillae Noda & Yamada, 1964; the latter species differed in having a smaller body, smaller buccal cavity and shorter spicules with spade-shaped membranes situated distally. Males of N. gorillae also possessed unusual cuticular thickenings on the dorsal side of the prebursal region of the body. These characters, shared with the male worm from the bonobo, correspond well to the description of N. gorillae described from gorillas in Congo. Conclusions: Based on the morphology of the hookworms recovered in this study and previous molecular analyses of larvae developed from both humans and western lowland gorillas (Gorilla gorilla gorilla) from this locality, we conclude that the researchers became infected with gorilla hookworms during their stay in the field. This is the first report of infection with a Necator species other than N. americanus in humans.