Zoonotic Soil-Transmitted Helminth Infections among Humans, Gabon.

BackgroundGastrointestinal parasites are neglected infections, yet they cause significant burden to animal and human health globally. To date, most studies of gastrointestinal parasites focus on host-parasite systems that involve either a single parasite or a host species. However, when hosts share habitat and resources, they may also cross-transmit generalist gastrointestinal parasites. Here we explore multi-host-parasite interactions in a single ecosystem to understand the infection patterns, especially those linked to livestock-wildlife interfaces and zoonotic risk.MethodsWe used both coprological methods (flotation and sedimentation; N = 1,138 fecal samples) and molecular identification techniques (rDNA and mtDNA; N = 18 larvae) to identify gastrointestinal parasites in nine sympatric host species (cattle, sheep, goats, wildebeest, Grant’s gazelles, Thomson’s gazelles, impala, vervet monkeys and baboons) in the Amboseli ecosystem, Kenya.ResultsWe found that the host community harbored a diverse community of gastrointestinal helminths, including 22 species and/or morphotypes that were heterogeneously distributed across the hosts. Six zoonotic gastrointestinal helminths were identified: Trichuris spp., Trichostrongylus colubriformis, Enterobius spp. Oesophagostomum bifurcum, Strongyloides stercoralis and Strongyloides fuelleborni. The dominant parasite was Trichuris spp, whose ova occurred in two morphological types. Baboons were co-infected with Strongyloides fuelleborni and S. stercoralis.ConclusionsWe found that the interface zone shared by wild ungulates, livestock and non-human primates is rich in diversity of gastrointestinal helminths, of which some are extensively shared across the host species. Closely related host species were most likely to be infected by the same parasite species. Several parasites showed genetic sub-structuring according to either geography or host species. Of significance and contrary to expectation, we found that livestock had a higher parasite richness than wild bovids, which is a health risk for both conservation and livestock production. The zoonotic parasites are of public health risk, especially to pastoralist communities living in areas contiguous to wildlife areas. These results expand information on the epidemiology of these parasites and highlights potential zoonotic risk in East African savanna habitats.

A rare case of imported Strongyloides fuelleborni infection in a Belgian student

The parasitic nematodes, Strongyloides stercoralis and Strongyloides fuelleborni, can infect humans and non-human primates. We amplified and sequenced a portion of the 18S ribosomal RNA gene (rRNA) and of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Strongyloides from humans in the study area in Thailand, where people have frequent contact with long-tailed macaques. Fresh stool samples were obtained from 213 people and were examined using the agar plate culture method. The overall prevalence of Strongyloides infection was 8.92% (19/213). From a total of 19 worms (one per infected person), 18 adult males had 18S rRNA sequences identical with that of S. stercoralis and one adult female had a sequence almost identical with that of S. fuelleborni. A median-joining network of cox1 sequences revealed nine new haplotypes from S. stercoralis, and an overall haplotype diversity (Hd) of 0.9309. The single haplotype of S. fuelleborni was also new and contributed to an overall haplotype diversity for that species of 0.9842. This is the first molecular identification of S. stercoralis and S. fuelleborni in a human community having contact with long-tailed macaques in Thailand. It is also the first report of S. fuelleborni infecting a human in Thailand.

Dengue human infection model: introduction.

Synanthropic rodents are involved in the transmission of several parasitic zoonoses to humans, such as helminth parasites. As part of a multidisciplinary study concerning the rodent population in Barcelona (Spain), 300 specimens of the Norway rat, Rattus norvegicus, were analyzed to elucidate their helminth community, mainly species with a zoonotic potential. The sample included 263 specimens from the sewage system and 37 from public gardens. A total of 253 (84.3%) rats were found to be parasitized, and 206 (68.7%) harbored zoonotic species. Adult rats were found to be more heavily parasitized with zoonotic helminths than juveniles, but the sex and site of capture had no influence. Six zoonotic helminths were identified: Hydatigera taeniaeformis larvae (1.7%), Rodentolepis nana (8.0%), Hymenolepis diminuta (21.3%), Calodium hepaticum (46.3%), Gongylonema neoplasticum (36.7%), and Moniliformis moniliformis (2.3%). Human zoonotic helminth infections often go unreported, so that the role of R. norvegicus in their transmission is unknown. According to our results, it is advisable to monitor and control rodent populations in deprived settlements close to cities and in cities themselves, and to promote good hygienic and sanitary practices, especially among vulnerable populations and workers with high exposure such as sewage workers.

Increasing contact between humans and non-human primates provides an opportunity for the transfer of potential pathogens or antimicrobial resistance between different host species. We have investigated genetic diversity and antimicrobial resistance in Escherichia coli isolates from a range of non-human primates dispersed across the Gambia: patas monkey (n=1), western colobus monkey (n=6), green monkey (n=14) and guinea baboon (n=22). From 43 stools, we recovered 99 isolates. We performed Illumina whole-genome shotgun sequencing on all isolates and nanopore long-read sequencing on isolates with antimicrobial resistance genes. We inferred the evolution of E. coli in this population using the EnteroBase software environment. We identified 43 sequence types (ten of them novel), spanning five of the eight known phylogroups of E. coli. Many of the observed sequence types and phylotypes from non-human primates have been associated with human extra-intestinal infection and carry virulence characteristics associated with disease in humans, particularly ST73, ST217 and ST681. However, we found a low prevalence of antimicrobial resistance genes in isolates from non-human primates. Hierarchical clustering showed that ST442 and ST349 from non-human primates are closely related to isolates from human infections, suggesting recent exchange of bacteria between humans and monkeys. Our results are of public health importance, considering the increasing contact between humans and wild primates.

Notes on the threadworm Strongyloides fuelleborni (Nematoda: Strongyloididae) in vervet monkeys (Chlorocebus pygerythrus) and zoonotic strongyloidiasis in southern Malawi

Nonhuman primates (NHPs) are threatened globally, with infectious diseases ranking among the major threat factors. NHPs may also harbor zoonotic pathogens that may spillover to humans, making the surveillance of infectious diseases and parasite infestations in NHPs of conservation and public health important. Here, we assessed the gastrointestinal helminths of sympatric green monkeys and olive baboons at the Shai Hill Resource Reserve (SHRR) in Accra, Ghana. Examination of 60 fecal samples from the two NHPs using direct wet mount preparations, formol‐ether sedimentation, and zinc‐sulfate centrifugal flotation techniques yielded 12 gastrointestinal helminth species comprising nine nematodes, two cestodes, and one trematode. Nine of the helminth species (6 nematodes, 2 cestodes, and 1 trematode) were common to the baboons and green monkeys, giving a high (86%) similarity of helminth composition between the two NHPs. The overall prevalence of gastrointestinal helminth infestations was significantly higher (p = 0.0002) in olive baboons (100%) than in green monkeys (86.7%). The prevalence of Enterobius sp. (χ2 = 30.03, p ≤ 0.00001) and Strongyloides sp. (χ2 = 19.53, p ≤ 0.0001) was significantly higher in green monkeys, while Oesophagostomum sp. (χ2 = 36.33, p ≤ 0.0001) was more prevalent in olive baboons. The occurrence of Taenia sp., Dipylidium sp., and Chabertia sp. in the NHPs suggests potential cross‐transmission of helminths between the NHPs, and both livestock and domestic animals within the fringe communities of SHRR. Ascaris sp., Enterobius sp., Oesophagostomum sp., Strongyloides sp., and Trichuris sp. in the NHPs are of public health interest because of their zoonotic nature. Our findings provide valuable baseline data for long‐term monitoring of the health of NHPs and their habitat and can inform conservation measures that safeguard wildlife, veterinary, and public health.

Rationale: Direct evidence for persistence of Mycobacterium tuberculosis (Mtb) during asymptomatic latent tuberculosis infection (LTBI) in humans is currently lacking. Moreover, although a 12-week regimen of once-weekly isoniazid and rifapentine (3HP) is currently recommended by the CDC as treatment for LTBI, experimental evidence for 3HP-mediated clearance of persistent Mtb infection in human lungs has not been established.Objectives: Using a nonhuman primate (NHP) model of TB, we sought to assess 3HP treatment-mediated clearance of Mtb infection in latently infected macaques.Methods: Sixteen NHPs were infected via inhalation with ∼10 cfu of Mtb CDC1551, after which asymptomatic animals were either treated with 3HP or left untreated. Pharmacokinetics of the 3HP regimen were measured. Following treatment, animals were coinfected with simian immunodeficiency virus to assess reactivation of LTBI and development of active TB disease.Measurements and Main Results: Fourteen NHPs remained free of clinical signs or microbiological evidence of active TB following infection with Mtb and were subsequently either treated with 3HP (n = 7) or left untreated (n = 7). Untreated NHPs were asymptomatic for 7 months but harbored persistent Mtb infection, as shown by reactivation of latent infection following simian immunodeficiency virus coinfection. However, none of the treated animals developed TB reactivation disease, and they remained without clinical or microbiological evidence of persistent bacilli, suggesting treatment-mediated clearance of bacteria.Conclusions:Mtb can persist in asymptomatic macaques for at least 7 months. Furthermore, 3HP treatment effectively cleared bacteria and prevented reactivation of TB in latently infected macaques.

Naturally Circulating Hepatitis A Virus in Olive Baboons, Uganda

B Virus infection in macaques rarely causes disease, and if so, it is in the form of mild ulcerative lesions. B virus polypeptides and glycoproteins can be grouped into classes that differ in their relative rates of synthesis at different times throughout the virus replication cycle, as is characteristic of alphaherpesviruses. During the course of B virus infection, several observations are common to the natural host, the experimentally infected host, and infected humans. B virus is an infection that humans rarely contract, but when they do, 80% of untreated cases result in death. Observations of the clinical pattern of disease are important for rapid diagnosis of B virus infection in both macaques and humans. The neutralization antibody test was the predominant diagnostic tool in macaques and humans for many decades. Currently, the most effective assay for diagnosis of B virus in a nonmacaque is a competition enzyme-linked immunosorbent assay (ELISA) to facilitate discrimination between specific and cross-reactive antibodies, similar to the challenge faced when diagnosing infection in humans. Multiple levels of prevention are used to prevent B virus infection in both humans and nonhuman primates, ranging from attempts to eliminate virus from colonies to designing methods to work safely in environments where there is an increased risk for contracting the agent.

Spirochetes are helical-shaped gram-negative bacteria that are important for the health of both nonhuman primates (NHPs) and humans. However, little is known about the spirochetes that naturally infect NHPs. Lyme disease and relapsing fever are caused by bacteria of the genus Borrelia, obligate parasites transmitted by arthropod vectors. Due to the close phylogenetic relationship of humans and NHPs and the importance of Borrelia infections in humans, translational NHP models have been developed. Leptospirosis, caused by different pathogenic bacteria of the genus Leptospira, affects both humans and NHPs. Naturally acquired and clinically apparent leptospirosis is rare in NHPs. However, clinically healthy animals tested positive for antibodies against the spirochete, indicating that NHPs might function as a disease reservoir for humans. Syphilis, yaws, and bejel represent infections caused by bacteria of the genus Treponema. Naturally occurring Treponema infection in NHPs, as well as the continual use of NHPs as experimental models for human treponematoses, have been documented. This chapter discusses three groups of spirochetes that cause considerable diseases in NHPs in the context of naturally and artificially acquired infection: Borrelia, Leptospira and Treponema. Essential is the One Health concept that addresses the connection and spread of diseases between humans and NHPs.

Background: Previous epidemiological studies have confirmed non-human primates (NHPs) as reservoirs for Cryptosporidium spp. , Giardia intestinalis, and Enterocytozoon bieneusi. It highlights the possibility of interspecies transmission between humans and macaques in laboratory animal facilities. This study aimed to investigate the prevalence of pathogenic intestinal protozoan infections in macaques and humans and to determine the risk of cross-species transmission from One Health view.Materials and Methods: A total of 360 fecal samples, including 310 from the four Macaca mulatta groups, 25 from the facility workers in a laboratory animal facility, and 25 from the villagers nearby in Yongfu country, southeast China, were collected. Nested PCR assays were done for detecting protozoan pathogens from all the specimens. Furthermore, potential risk factors (gender, age, and direct contact) on the occurrence of intestinal protozoa infection among different sub-groups were evaluated. A phylogenetic and haplotype network analysis was conducted to examine the genetic structure and shared patterns of E. bieneusi and Cyclospora cayetanensis.Results: The pathogenic intestinal protozoa were detected in both human and macaque fecal samples. A total of 134 (37.2%) samples were tested positive, which included 113 (36.4%) macaques, 14 (56.0%) facility workers, and 7 (28.0%) villagers, respectively. There was no significant difference in four intestinal protozoa infections between facility workers and villagers (χ2 = 2.4, P > 0.05). However, the positive rate of pathogenic intestinal protozoa in the facility workers, who had direct contact with macaques, was significantly higher [odds ratio (OR) = 0.31, 95% confidence interval (CI): 0.09–1.00, P < 0.05).Thirty-three ITS genotypes of E. bieneusi were identified, including five known genotypes (PigEBITS7, Peru8, Henan V, D, and CM1) and six novel genotypes (MEB1–6). Seven haplotypes were identified in the network analysis from C. cayetanensis-positive samples. Meanwhile, a phylogenetic and haplotype analysis confirmed the presence of zoonotic subtypes in NHPs and humans.Conclusion: The data collected from this study confirmed a high prevalence of intestinal protozoan infection in humans and macaques. These results warrant workers of such facilities and residents to limit contact with infected animals in order to minimize related health risks. The need for comprehensive strategies to mitigate the risk of zoonotic transmission, especially from a One Health perspective, is recommended.

Treponemal Infection in Nonhuman Primates as Possible Reservoir for Human Yaws

Simian T-lymphotropic virus 1 (STLV-1) enters human populations through contact with nonhuman primate (NHP) bushmeat. We tested whether differences in the extent of contact with STLV-1-infected NHP bushmeat foster regional differences in prevalence of human T-lymphotropic virus 1 (HTLV-1). Using serological and PCR assays, we screened humans and NHPs at two Sub-Saharan African sites where subsistence hunting was expected to be less (Taï region, Côte d'Ivoire [CIV]) or more (Bandundu region, Democratic Republic of the Congo [DRC]) developed. Only 0.7% of human participants were infected with HTLV-1 in CIV (n = 574), and 1.3% of humans were infected in DRC (n = 302). Two of the Ivorian human virus sequences were closely related to simian counterparts, indicating ongoing zoonotic transmission. Multivariate analysis of human demographic parameters and behavior confirmed that participants from CIV were less often exposed to NHPs than participants from DRC through direct contact, e.g., butchering. At the same time, numbers of STLV-1-infected NHPs were higher in CIV (39%; n = 111) than in DRC (23%; n = 39). We conclude that similar ultimate risks of zoonotic STLV-1 transmission-defined as the product of prevalence in local NHP and human rates of contact to fresh NHP carcasses-contribute to the observed comparable rates of HTLV-1 infection in humans in CIV and DRC. We found that young adult men and mature women are most likely exposed to NHPs at both sites. In view of the continued difficulties in controlling zoonotic disease outbreaks, the identification of such groups at high risk of NHP exposure may guide future prevention efforts.IMPORTANCE Multiple studies report a high risk for zoonotic transmission of blood-borne pathogens like retroviruses through contact with NHPs, and this risk seems to be particularly high in tropical Africa. Here, we reveal high levels of exposure to NHP bushmeat in two regions of Western and Central tropical Africa. We provide evidence for continued zoonotic origin of HTLV-1 in humans at CIV, and we found that young men and mature women represent risk groups for zoonotic transmission of pathogens from NHPs. Identifying such risk groups can contribute to mitigation of not only zoonotic STLV-1 transmission but also transmission of any blood-borne pathogen onto humans in Sub-Saharan Africa.