Humans and Great Apes Cohabiting the Forest Ecosystem in Central African Republic Harbour the Same Hookworms

Background Hookworms are important pathogens of humans. To date, Necator americanus is the sole, known species of the genus Necator infecting humans. In contrast, several Necator species have been described in African great apes and other primates. It has not yet been determined whether primate-originating Necator species are also parasitic in humans. Methodology/Principal Findings The infective larvae of Necator spp. were developed using modified Harada-Mori filter-paper cultures from faeces of humans and great apes inhabiting Dzanga-Sangha Protected Areas, Central African Republic. The first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA and partial cytochrome c oxidase subunit 1 (cox1) gene of mtDNA obtained from the hookworm larvae were sequenced and compared. Three sequence types (I–III) were recognized in the ITS region, and 34 cox1 haplotypes represented three phylogenetic groups (A–C). The combinations determined were I-A, II-B, II-C, III-B and III-C. Combination I-A, corresponding to N. americanus, was demonstrated in humans and western lowland gorillas; II-B and II-C were observed in humans, western lowland gorillas and chimpanzees; III-B and III-C were found only in humans. Pairwise nucleotide difference in the cox1 haplotypes between the groups was more than 8%, while the difference within each group was less than 2.1%. Conclusions/Significance The distinctness of ITS sequence variants and high number of pairwise nucleotide differences among cox1 variants indicate the possible presence of several species of Necator in both humans and great apes. We conclude that Necator hookworms are shared by humans and great apes co-habiting the same tropical forest ecosystems

No impact of strongylid infections on the detection of Plasmodium spp. in faeces of western lowland gorillas and eastern chimpanzees

[Background] Although a high genetic diversity of Plasmodium spp. circulating in great apes has been revealed recently due to non-invasive methods enabling detection in faecal samples, little is known about the actual mechanisms underlying the presence of Plasmodium DNA in faeces. Great apes are commonly infected by strongylid nematodes, including hookworms, which cause intestinal bleeding. The impact of strongylid infections on the detection of Plasmodium DNA in faeces was assessed in wild, western, lowland gorillas from Dzanga Sangha Protected Areas, Central African Republic and eastern chimpanzees from Kalinzu Forest Reserve, Uganda. [Methods]Fifty-one faecal samples from 22 habituated gorillas and 74 samples from 15 habituated chimpanzees were analysed using Cytochrome-b PCR assay and coprological methods. [Results]Overall, 26.4% of the analysed samples were positive for both Plasmodium spp. and strongylids. However, the results showed no significant impact of intensity of infections of strongylids on detection of Plasmodium DNA in gorilla and chimpanzee faeces. [Conclusion]Bleeding caused by strongylid nematode Necator spp. cannot explain the presence of Plasmodium DNA in ape faeces

Do habituation, host traits and seasonality have an impact on protist and helminth infections of wild western lowland gorillas?

Increased anthropogenic activity can result in parasite exchanges and/or general changes in parasite communities, imposing a health risk to great apes. We studied protist and helminth parasites of wild western lowland gorilla groups in different levels of habituation, alongside humans inhabiting Dzanga-Sangha Protected Areas in the Central African Republic. Faeces were collected yearly during November and December from 2007 to 2010 and monthly from November 2010 to October 2011. Protist and helminth infections were compared among gorilla groups habituated, under habituation and unhabituated, and the effect of host traits and seasonality was evaluated. Zoonotic potential of parasites found in humans was assessed. No significant differences in clinically important parasites among the groups in different stages of habituation were found, except for Entamoeba spp. However, humans were infected with four taxa which may overlap with taxa found in gorillas. Females were less infected with spirurids, and adults had higher intensities of infection of Mammomonogamus sp. We found seasonal differences in the prevalence of several parasite taxa, but most importantly, the intensity of infection of unidentified strongylids was higher in the dry season. This study highlights that habituation may not necessarily pose a greater risk of protist and helminth infections in gorilla groups

Amino acid substitutions found among the haplotypes of partial <i>cox1</i> gene.

<p>* No. of haplotypes.</p

Comparison of ITS-1 sequences of hookworms from apes and humans from Dzanga Sangha Protected Areas.

<p>Host and accession number in DNA database are given in parentheses. Dots indicate homologous nucleotides with <i>N. americanus</i> (<i>N. a.</i>) from Guatemala (AF217891); dash indicates absence of nucleotide. Major indels are shaded.</p

Comparison of ITS-2 sequences of hookworms from apes and humans from Dzanga Sangha Protected Areas.

<p>Host and accession number in DNA database are given in parentheses. Dots indicate homologous nucleotides with <i>N. americanus</i> (<i>N. a.</i>) from Guatemala (AF217891); dash indicates absence of nucleotide. Major indels are shaded.</p

Amplification of partial ITS-1 region using specific primers.

<p>Primers AmerF3 and AmerR2 only amplified specific band of about 250-1, while no clear band was formed for types II and III. CongF and Nem5.8R resulted in formation of specific band of about 650 bp for types II and III, while prominent bands were not formed for type I.</p

Evolutionary relationships of <i>Necator</i> spp. from apes and humans in Dzanga-Sangha Protected Areas.

<p>Tree was reconstructed by Neighbor-Joining method on mtDNA <i>cox1</i> sequences each with 669 nucleotides. Host and accession number in DNA database in parentheses are given at each branch. Humans are CAR people except for two Europeans marked with asterisks, who acquired the infection in CAR. Bootstrap values larger than 50 are shown.</p

Restriction enzyme digestion of DNA sequences amplified with Civ18S1500F and Nem5.8R.

<p>By digestion with <i>Alu</i> I, two bands were formed for type I in area from 200 to 500 bp, while only one band was formed for types II and III. By digestion using <i>Hinc</i> II, two bands of about 300 and 500 bp were formed for type I, while only one band similar to original band was visible for types II and III.</p

Map of study site in Dzanga-Sangha Protected Areas, Central African Republic.

<p>Dark grey – Dzanga and Ndoki Sectors of the protected Dzanga Ndoki National Park; light grey - Dzanga Sangha Dense Forest Special Reserve; 1 – location of villages Bayanga, Mossapoula and Yandumbé; M – research camp Mongambe; B – research camp Bai Hokou.</p