Parasites of Free-Ranging and Captive American Primates: A Systematic Review

Diversity of gastrointestinal parasites and molecular characterization of Giardia duodenalis in free-living and captive howler monkeys (Alouatta guariba clamitans) in southern Brazil

Non-human primates (NHPs) are the group that most share infectious agents with humans due to their close taxonomic relationship. The southern brown howler monkeys (Alouatta guariba clamitans) are endemic primates from Brazil and Argentina's Atlantic Forest. This study aimed to investigate the presence of intestinal parasites in free-living (FL) and captive (CA) southern brown howler monkeys. Thirty-nine stool samples were collected in two areas in southern Brazil, 15 FL and 24 CA. Stool sediments obtained by centrifugal sedimentation technique were used for microscopic analysis and direct immunofluorescence assay and evaluated by molecular analysis through amplification and sequencing of TPI fragments. Intestinal parasites Giardia duodenalis, Cryptosporidium spp., and Trypanoxyuris minutus were detected at coproparasitological analysis. This is the first report of the presence of Cryptosporidium spp. in free-living howlers. The molecular characterization of G. duodenalis isolates indicated assemblage B for the first time found in free-living A. guariba clamitans. The high prevalence of G. duodenalis transmission in CA howler monkeys can be explained by direct contact with humans and frequent soil contact. The presence of a potentially zoonotic assemblage in these animals indicates that the process of fragmentation and cohabitation with humans and livestock affects the wildlife, thus indicating a need for eco-health measures.

Comparison of DNA quantity and quality from fecal samples of mammals transported in ethanol or lysis buffer

Using fecal microbial community profiles through sequencing approaches helps to unravel the intimate interplay between health, wellness, and diet in wild animals with their environment. Ensuring the proper preservation of fecal samples before processing is crucial to ensure reliable results. In this study, we evaluated the efficiency of two different preservation methods, considering the following criteria: DNA yield, quality and integrity, and microbial community structure based on Oxford Nanopore amplicon sequencing of the V3-V4 region of bacterial 16S rRNA and protozoa 18S rRNA genes. Eighteen matched pairs of mammalian fecal samples were collected and transported in 99.8% ethanol and lysis buffer; processing occurred between 55 and 461 days post-collection. Wilcoxon signed-rank tests were used to analyze quantitative measurements for paired samples. The A260/280 ratio, a measure of nucleic acid purity, was assessed descriptively for each media, and the Bartlett test evaluated dispersion of this ratio. A Fisher test was performed to compare the number of positive reactions for DNA extraction or PCR amplification of the 16S and 18S rRNA genes between both media. The concentration of total DNA and amplicons, as well as the number of reads obtained in sequencing, was significantly higher in the samples preserved with lysis buffer compared to ethanol, with magnitudes up to three times higher. Electrophoretic analysis of total DNA and amplicons further confirmed superior DNA integrity in lysis buffer preserved samples. The A260/280 values  obtained using the lysis buffer were of optimal purity (mean: 1.92) and with little dispersion (SD: 0.27); on the other hand, the ethanol samples also presented an excellent average quality (mean: 1.94), but they were dispersed (SD: 1.10). For molecular studies using mammalian feces, the lysis buffer reagent proved to be a reliable solution for their collection, conservation, and storage.

Diversity and prevalence of zoonotic infections at the animal-human interface of primate trafficking in Peru

Wildlife trafficking creates favorable scenarios for intra- and inter-specific interactions that can lead to parasite spread and disease emergence. Among the fauna affected by this activity, primates are relevant due to their potential to acquire and share zoonoses - infections caused by parasites that can spread between humans and other animals. Though it is known that most primate parasites can affect multiple hosts and that many are zoonotic, comparative studies across different contexts for animal-human interactions are scarce. We conducted a multi-parasite screening targeting the detection of zoonotic infections in wild-caught monkeys in nine Peruvian cities across three contexts: captivity (zoos and rescue centers, n = 187); pet (households, n = 69); and trade (trafficked or recently confiscated, n = 132). We detected 32 parasite taxa including mycobacteria, simian foamyvirus, bacteria, helminths, and protozoa. Monkeys in the trade context had the highest prevalence of hemoparasites (including Plasmodium malariae/brasilianum, Trypanosoma cruzi, and microfilaria) and enteric helminths and protozoa were less common in pet monkeys. However, parasite communities showed overall low variation between the three contexts. Parasite richness (PR) was best explained by host genus and the city where the animal was sampled. Squirrel (genus Saimiri) and wooly (genus Lagothrix) monkeys had the highest PR, which was ~2.2 times the PR found in tufted capuchins (genus Sapajus) and tamarins (genus Saguinus/Leontocebus) in a multivariable model adjusted for context, sex, and age. Our findings illustrate that the threats of wildlife trafficking to One Health encompass exposure to multiple zoonotic parasites well-known to cause disease in humans, monkeys, and other species. We demonstrate these threats continue beyond the markets where wildlife is initially sold; monkeys trafficked for the pet market remain a reservoir for and contribute to the translocation of zoonotic parasites to households and other captive facilities where contact with humans is frequent. Our results have practical applications for the healthcare of rescued monkeys and call for urgent action against wildlife trafficking and ownership of monkeys as pets.

Molecular data aids pinworm diagnosis in night monkeys (Aotus spp., Primates: Aotidae) with the resurrection of a Trypanoxyuris species (Nematoda: Oxyuridae)

Neotropical primates (Platyrrhines) are commonly parasitized by pinworm nematodes of the genus Trypanoxyuris Vevers, 1923. The taxonomic identity of Trypanoxyuris sampled in night monkeys (Aotus Iliger) has been rather controversial. Two species have been described, namely T. microon (Linstow, 1907) and T. interlabiata (Sandosham, 1950). The latter was synonymized with T. microon considering that the observed morphological differences corresponded to different developmental stages of the nematode rather than to differences between both species. Here, we used an integrative taxonomy approach, based on morphological and molecular data along with host identity, in order to assess the validity of both species. Our results evidenced that these different morphotypes correspond to different and reciprocally monophyletic groups; thus, we propose the resurrection of T. interlabiata. We redescribe both pinworm species using specimens sampled in Aotus monkeys from Colombia and discuss the advantages of combining molecular and morphological data to uncover pinworm diversity, and to understand the potential forces determining the diversification process in pinworms from platyrrhine primates.

Threat Analysis of Forest Fragmentation and Degradation for Peruvian Primates

Peru has 55 primate taxa (including all species and subspecies), a third of which are threatened. The major drivers of habitat loss, degradation and fragmentation are grazing, forestry, agriculture and transport infrastructure. Other activities such as hunting exacerbate these threats. We assessed the threats from degradation and fragmentation facing Peruvian primates to aid in the design and implementation of mitigation strategies. Through GIS-based mapping, statistical modeling and specialist assessments, we evaluated all primate taxa using the IUCN Conservation Measures Partnership Unified Classifications of Direct Threats across five categories (direct threats to primates, threats to habitat, causes of fragmentation, factors exacerbating fragmentation and threats to primates and habitats as a consequence of fragmentation), highlighting which were most common and most severe. Our results showed that all primate taxa were affected by degradation and fragmentation in Peru. The most common and severe direct threat was hunting, whereas housing and urban development, smallholder crop farming, smallholder grazing and large-scale logging were the most common and severe threats across the other categories. The families Cebidae and Atelidae face the highest overall threat. Our analysis showed that the current IUCN listing of Leontocebus leucogenys [LC] underestimates the true threat level this species faces and that Lagothrix lagothricha tschudii [DD] should be listed under one of the threat categories. In Peru, the need for mitigating the threat of habitat fragmentation is clear. To ensure the survival of Peru’s diverse primate taxa, forest connectivity needs to be maintained or recovered through the protection and restoration of key areas considering their biological and social needs.

The global prevalence of parasites in non-biting flies as vectors: a systematic review and meta-analysis

BACKGROUND

Non-biting flies such as the house fly (Musca domestica), the Australian sheep blowfly (Lucilia cuprina) and the oriental latrine fly (Chrysomya megacephala) may carry many parasites. In the present study, we performed a systematic overview of the different species of parasites carried by non-biting flies, as well as of isolation methods, different geographical distribution, seasonality and risk assessment.

METHODS

A meta-analysis was carried out with the aim to review the global prevalence of parasite transmission in non-biting flies. A total sample size of 28,718 non-biting flies reported in studies worldwide satisfied the predetermined selection criteria and was included in the quantitative analysis.

RESULTS

The global prevalence of parasites in non-biting flies was 42.5% (95% confidence interval [CI] 31.9-53.2%; n = 15,888/28,718), with the highest prevalence found for non-biting flies in Africa (58.3%; 95% CI 47.4-69.3%; n = 9144/13,366). A total of 43% (95% CI 32.1-54.4%; n = 7234/15,282) of house flies (M. domestica), the fly species considered to be the most closely associated with humans and animals, were found with parasites. The prevalence of parasites in the intestine of non-biting flies was 37.1% (95% CI 22.7-51.5%; n = 1045/3817), which was significantly higher than the prevalence of parasites isolated from the body surface (35.1%; 95% CI 20.8-49.4%; n = 1199/3649; P < 0.01). Of the 27 reported parasites, a total of 20 known zoonotic parasites were identified, with an infection rate of 38.1% (95% CI 28.2-48.0%; n = 13,572/28,494).

CONCLUSIONS

This study provides a theoretical basis for the public health and ecological significance of parasites transmitted by non-biting flies.

First Molecular Identification of Trypanosomes and Absence of Babesia sp. DNA in Faeces of Non-Human Primates in the Ecuadorian Amazon

Trypanosomes are a group of pathogens distributed in the continents of Africa, America, Asia and Europe, and they affect all vertebrates including the neotropical primate group. Information about the trypanosome's diversity, phylogeny, ecology and pathology in non-human primates (NHPs) from the neotropical region is scarce. The objective of the study was to identify Trypanosoma and Babesia molecularly in NHPs under the phylogenetic species concept. We extracted DNA from a total of 76 faecal samples collected between 2019 and 2021, from a total of 11 non-human primate species of which 46 are from captive NHPs and 30 are free-living NHPs in the Western Amazon region of Ecuador. We did not detect DNA of Babesia sp. by polymerase chain reaction test in any of the faecal samples. However, the nested-PCR-based method revealed Trypanosoma parasites by ITS gene amplification in two faecal samples; one for the species Leontocebus lagonotus (from the captive population) and a second one for Cebus albifrons (from the free-ranging population). Maximum parsimony and likelihood methods with the Kimura2+G+I model inferred the evolutionary history of the two records, which showed an evolutionary relationship with the genus Trypanosoma. Two sequences are monophyletic with Trypanosoma. However, the number of sequences available in GenBank for their species identification is limited. The two samples present different molecular identifications and evolutionary origins in the tree topology. We are most likely referring to two different species, and two different localities of infection. We suggest that health management protocols should be implemented to prevent the transmission of blood-borne pathogens such as Trypanosoma sp. among captive populations. In addition, these protocols also protect the personnel of wildlife rehabilitation centers working in close proximity to NHPs and vice versa.