Nuclear and Mitochondrial Data on Trichuris from Macaca fuscata Support Evidence of Host Specificity

Intestinal parasites infecting captive non-human primates in Italy

Non-human primates (NHPs) living in captive conditions are susceptible to intestinal parasites that can contribute to mortality and morbidity, and cause zoonotic infections. Thus, parasite surveys on NHP populations under human care are relevant as part of the evaluation of NHPs welfare and in the zoonotic disease risk assessment, as well as in the exploration of parasite transmission pathways, according to the One-Health concept. This study aimed to identify intestinal parasites infecting NHPs living in two wildlife recovery centers and in a zoological garden, in Italy. Ninety-three fecal samples from Macaca tonkeana, Macaca fascicularis, Sapajus apella, Chlorocebus aethiops, Macaca fuscata, Macaca sylvanus, and Cebus capucinus were collected at Piano dell'Abatino Park (Lazio), and fecal smears and flotation were performed in order to identify parasites according to morphological keys. Additionally, one carcass of M. fuscata from the Bioparco Zoological Garden of Rome (Lazio) and one of M. fascicularis from the Center for the Recovery of Exotic and Maremma Wild Animals (Tuscany) were necropsied and intestinal adult nematodes were collected and characterized at morphological and molecular level, using the mitochondrial cox1 and rrnL markers. Protozoans (Entamoeba coli, Iodamoeba bütschlii, Dientamoeba fragilis-like, Giardia sp.), chromists (Balantidium/Buxtonella sp.) and nematodes (Capillaria sp., Trichuris sp., strongyliform larvae and Oesophagostomum sp.) were found through fecal smears and flotation. The collected adult nematodes from dead NHPs were morphologically identified as whipworms (genus Trichuris). Phylogenetic analyses grouped Trichuris specimens into the Trichuris trichiura complex of species, with specimens from M. fuscata clustering into a host-specific branch, and whipworms from M. fascicularis clustering within a clade formed by Trichuris infecting several primate species, including humans. The results here collected revealed the presence of potentially zoonotic parasites circulating in captive primates in Italy, providing useful information for the formulation of management and care plans for captive NHPs, and for the elaboration of safety measures for visitors and animal keepers.

Prevalence of gastrointestinal parasites in captive mammals at Khon Kaen Zoo, Thailand

Background and Aim

Captive animals are susceptible to parasitic diseases due to the stress and confinement they experience. In addition, they can serve as reservoirs of zoonotic parasites that have the potential to infect humans. To investigate this possibility, we estimated the prevalence of gastrointestinal (GI) parasites in captive mammals at Khon Kaen Zoo, Thailand.

Materials and Methods

One hundred and forty-seven individual mammals (37 primates, 43 carnivores, 62 herbivores, and 5 rodents) were examined for parasitic infections by fecal examination daily for 3 consecutive days using the formalin-ethyl acetate concentration technique (FECT) and the agar plate culture method.

Results

According to FECT, the overall prevalence of GI parasites was 62.6% (92/147). Within animal groups, the numbers were as follows: 67.6% (25/37) in primates, 23.3% (10/43) in carnivores, 85.5% (53/62) in herbivores, and 80.0% (4/5) in rodents. Using the agar plate culture method, 21.43% (27/126) were positive for Strongyloides spp. and hookworm infections. The GI parasites identified belonged to three categories: protozoa (including Entamoeba histolytica species complex, Entamoeba coli, Giardia spp., coccidia, and ciliated protozoa), trematodes (minute intestinal flukes and rumen flukes), and nematodes (strongyle/hookworm, Strongyloides spp., Ascarididae, and Trichuris spp.).

Conclusion

The findings of this study indicate the prevalence of several GI parasites in zoo animals with the potential for transmission to humans, given the animals' close proximity to both visitors and animal caretakers.

De novo assembled mitogenome analysis of Trichuris trichiura from Korean individuals using nanopore-based long-read sequencing technology

Knowledge about mitogenomes has been proven to be essential in human parasite diagnostics and understanding of their diversity. However, the lack of substantial data for comparative analysis is still a challenge in Trichuris trichiura research. To provide high quality mitogenomes, we utilized long-read sequencing technology of Oxford Nanopore Technologies (ONT) to better resolve repetitive regions and to construct de novo mitogenome assembly minimizing reference biases. In this study, we got three de novo assembled mitogenomes of T. trichiura isolated from Korean individuals. These circular complete mitogenomes of T. trichiura are 14,508 bp, 14,441 bp, and 14,440 bp in length. A total of 37 predicted genes were identified consisting of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNAs) genes, two ribosomal RNA (rRNA) genes (rrnS and rrnL), and two non-coding regions. Interestingly, the assembled mitogenome has up to six times longer AT-rich regions than previous reference sequences, thus proving the advantage of long-read sequencing in resolving unreported non-coding regions. Furthermore, variant detection and phylogenetic analysis using concatenated protein coding genes, cox1, rrnL, and nd1 genes confirmed the distinct molecular identity of this newly assembled mitogenome while at the same time showing high genetic relationship with sequences from China or Tanzania. Our study provided a new set of reference mitogenome with better contiguity and resolved repetitive regions that could be used for meaningful phylogenetic analysis to further understand disease transmission and parasite biology.