Detection and genetic characterization of "Candidatus Mycoplasma haemomacaque" infection among long-tailed macaques (Macaca fascicularis) in Thailand using broad-range nested polymerase chain reaction assay

Zoonotic pathogens in wild Asian primates: a systematic review highlighting research gaps

Introduction

Ongoing global changes, including natural land conversion for agriculture and urbanization, modify the dynamics of human-primate contacts, resulting in increased zoonotic risks. Although Asia shelters high primate diversity and experiences rapid expansion of human-primate contact zones, there remains little documentation regarding zoonotic surveillance in the primates of this region.

Methods

Using the PRISMA guidelines, we conducted a systematic review to compile an inventory of zoonotic pathogens detected in wild Asian primates, while highlighting the coverage of primate species, countries, and pathogen groups surveyed, as well as the diagnostic methods used across the studies. Moreover, we compared the species richness of pathogens harbored by primates across diverse types of habitats classified according to their degree of anthropization (i.e., urban vs. rural vs. forest habitats).

Results and discussion

Searches of Scopus, PubMed, and the Global Mammal Parasite Database yielded 152 articles on 39 primate species. We inventoried 183 pathogens, including 63 helminthic gastrointestinal parasites, two blood-borne parasites, 42 protozoa, 45 viruses, 30 bacteria, and one fungus. Considering each study as a sample, species accumulation curves revealed no significant differences in specific richness between habitat types for any of the pathogen groups analyzed. This is likely due to the insufficient sampling effort (i.e., a limited number of studies), which prevents drawing conclusive findings. This systematic review identified several publication biases, particularly the uneven representation of host species and pathogen groups studied, as well as a lack of use of generic diagnostic methods. Addressing these gaps necessitates a multidisciplinary strategy framed in a One Health approach, which may facilitate a broader inventory of pathogens and ultimately limit the risk of cross-species transmission at the human-primate interface. Strengthening the zoonotic surveillance in primates of this region could be realized notably through the application of more comprehensive diagnostic techniques such as broad-spectrum analyses without a priori selection.

Post-mortem detection of hemoplasmas (hemotropic Mycoplasma spp.) in South American fur seal (Arctocephalus australis) sampled in Rio Grande do Sul State, southern Brazil

Hemotropic mycoplasmas are bacteria that attaches to erythrocytes surface, which some species presents zoonotic concerns. In the suborder Pinnipedia, genera Otaria and Arctocephalus are prominent in Brazil. This study investigated the occurrence of hemoplasmas in Arctocephalus sp. and Otaria flavescens found dead along the coast of a Southern Brazilian State. DNA from 135 spleen samples were extracted and subjected to conventional PCR protocols, targeting the 16 S rRNA and 23 S rRNA gene. Three (2.22 %) Arctocephalus australis were positive in the 16 S rRNA gene, and no samples amplified in the 23 S rRNA gene. Samples from this study clustered with Zalophus californianus and Arctocephalus tropicalis mycoplasmas on a Bayesian phylogenetic analysis. Genetic diversity analysis suggested distinct genotypes, indicating A. australis as a new host for hemoplasma, and also a potential putative novel hemoplasma genotype. These findings raises future awareness for pinnipeds conservation, and adds Mycoplasma spp. to be taken into consideration when clinically evaluating rescued animals.

Molecular Detection and Characterization of Hemotropic Mycoplasma in Assamese Macaques (Macaca assamensis) of Northern Thailand

Hemotropic mycoplasmas, also known as hemoplasmas, are parasitic bacteria that infect red blood cells, potentially leading to varying degrees of anemia across numerous mammalian species, including nonhuman primates. The present study aims to investigate the prevalence of hemoplasma infection and identify the species involved among free-ranging Assamese macaques (Macaca assamensis) inhabiting northern Thailand. A total of 133 blood samples were collected from Assamese macaques in Chiang Rai province, Thailand, and subjected to screening for hemoplasma infection utilizing nested PCR amplification targeting the 16S rRNA gene. Positive samples were subsequently analyzed through nucleotide sequencing and phylogenetic analysis for putative species identification. Current study results revealed that 17.3% (23/133; 95% CI 11.29-24.81) of Assamese macaques tested positive for hemoplasma infection using the nested PCR assay. Partial 16S rRNA sequences derived from hemoplasma isolates in Assamese macaques exhibited 99% homology, forming a cluster within the same phylogenetic clade as "Candidatus Mycoplasma haematomacacae," previously identified in long-tailed macaques, rhesus macaques, and Japanese macaques. These findings suggest the presence of "Ca. M. haematomacacae" not only in long-tailed macaques and rhesus macaques but also in Assamese macaques in Thailand. To our knowledge, this marks the first molecular detection of "Ca. M. haematomacacae" in Assamese macaques in Thailand. These results hold significance as they enhance our understanding of hemoplasma infection distribution among macaque populations in Thailand.

Multi-locus sequence analysis of 'Candidatus Mycoplasma haematomacacae' in free-ranging macaques from Thailand suggestive of a closer relationship to hemotropic mycoplasmas in capuchins and potential origin from bats

Although 'Candidatus Mycoplasma haematomacacae' (formerly known as 'Candidatus Mycoplasma haemomacaque') has been reported on extensively in macaques from Thailand, the USA, Japan, and Brazil, its genetic characterization has primarily been restricted to the 16S rRNA sequences with no exploration on multi-locus sequence analysis. The primary goal of this study was to characterize 'Ca. M. haematomacacae' among Thai macaques based on multiple genetic markers. Between April 2018 and November 2021, blood samples were taken from 580 free-ranging macaques (560 Macaca fascicularis and 20 Macaca nemestrina) in 15 locations encompassing 10 provinces throughout Thailand. Using the conventional PCR assay targeting the 16S ribosomal RNA (16S rRNA) gene, 338 out of 580 macaques (58.27 %) tested hemoplasma-positive. Of these, 40 positive samples were further subjected to DNA sequencing, and all were identified as 'Ca. M. haematomacacae'. Subsequently, the partial nucleotide sequences of 23S ribosomal RNA (23S rRNA) and RNase P RNA (rnpB) genes of this particular hemoplasma species were amplified through nested PCR assay. The analysis of multi-locus genetic markers revealed that the 23S rRNA and rnpB sequences exhibited higher levels of genetic diversity than the 16S rRNA sequences. Furthermore, the 16S rRNA analyses demonstrated that 'Ca. M. haematomacacae' infecting Old World monkeys (Macaca spp.) was most closely related to hemotropic Mycoplasma spp. in black-capped capuchins (Sapajus apella) and Marcgrave's capuchins (Sapajus flavius) from Brazil, as well as establishing a common ancestor clade with hemotropic Mycoplasma spp. from the Neotropical bats in Belize and Peru and an Old World bat in Spain. The 23S rRNA analyses likewise evidenced that 'Ca. M. haematomacacae' formed a sister clade with hemotropic Mycoplasma spp. in Neotropical bats from Belize and Panama. Thus, the present findings, based on multi-locus sequence analysis, suggest a potential origin of 'Ca. M. haematomacacae' from Neotropical and Old World bats. To the best of the authors' knowledge, this study provided the largest dataset so far of multi-locus genetic sequences of 'Ca. M. haematomacacae' isolated from Thai macaques and enhanced the accuracy of phylogenetic analyses, providing insights into their origins among hemotropic Mycoplasma spp. discovered worldwide.