Diatta, G. | Search bioRxiv

bioRxiv2026

Continental-scale survey of Treponema pallidum in African nonhuman primates: expanding the range to the Mediterranean basin

Background: Treponema pallidum, the causative agent of yaws, bejel, and syphilis, is a significant pathogen affecting both humans and nonhuman primates (NHPs). While its presence is documented in several African NHP species, the continental-scale distribution, ecological drivers, and status in North African populations remain poorly understood. We conducted a large-scale, non-invasive survey to investigate the circulation of T. pallidum across African NHP populations and evaluate geographical and ecological patterns of exposure. Results: A total of 1,696 fecal samples from 11 wild NHP species collected across five African countries were screened for anti-T. pallidum antibodies using an automated chemiluminescent Simple Western assay, and fecal and dipteran samples were analyzed by molecular methods. Widespread seropositivity was observed across all African sites and multiple primate taxa, including great apes and cercopithecids. We provide the first evidence of T. pallidum antibodies in Barbary macaques (Macaca sylvanus) from North Africa, extending the known distribution of the pathogen to the Mediterranean basin. In West Africa, chimpanzees (Pan troglodytes verus) from Senegal and Guinea exhibited particularly high seroprevalence, confirming this region as a major endemic hotspot. In Central Africa, substantial circulation was documented in Cercopithecus wolfi, Cercopithecus ascanius, and western lowland gorillas (Gorilla gorilla gorilla). Arid/savanna biomes showed significantly higher exposure than Mediterranean and tropical rainforest biomes. No T. pallidum DNA was detected in fecal or dipteran samples. Conclusion: Our findings demonstrate widespread circulation of T. pallidum among African NHPs, reveal its presence in North African primate populations for the first time. The observed high seroprevalence, coupled with significant variations across species and geographical regions, suggests the existence of multiple transmission pathways adapted to specific host behaviors and environmental constraints. These results support the existence of a broad multihost sylvatic reservoir and provide new insights into the ecology of T. pallidum, with important implications for wildlife health, One Health surveillance, and yaws eradication efforts.

microbiology↗

bioRxiv2018

FilmArray Respiratory Panel Integrated in a field Point Of Care dispositive for the diagnosis of respiratory tract infections in rural areas in Senegal

The development of molecular syndrome-based kits for the diagnosis of respiratory infections offers rapid and sensitive detection of common respiratory pathogens and will have a significant impact on the care of patients. In this study, we present the results obtained after the introduction of the FilmArray respiratory panel in a field Point of care (POC) for the diagnosis of virus and bacteria responsible of respiratory tract infections in Senegal rural area. From February to August 2017, we collected nasal swabs from febrile patients that presented symptoms of respiratory tract infections in three health posts located in Niakhar. Specimens were tested on site by multiplex Polymerase Chain Reaction (PCR), using the FilmArray respiratory panel(R) that targets 20 pathogens, including 17 virus and 3 bacteria (bioMerieux). Nasal swabs were collected from 113 patients. The median age was 4 years (ranging from 4 months to 60 years) and 51 (45%) were males. The prevalence of respiratory pathogens was 37.5% (12/32) during the dry season and 54.3% (44/81) in the rainy season (p=0.16). The prevalence of respiratory pathogen carriage was higher in children under 5 years of age (38/55, 69.1%). The most prevalent micro-organisms detected were influenza B virus (16/113, 14%), human rhinovirus/enterovirus (10/113, 9%), parainfluenzae virus (9/113, 8%), respiratory syncytial virus (8/113, 7%), adenovirus (5/113, 4%), human metapneumovirus (3/113, 3%), Chlamydia pneumoniae (2/113, 2%) and Coronavirus (2/113, 2%). The study has demonstrated that the integration of the FilmArray respiratory panel into a field POC could significantly improve the management of respiratory tract infections in rural areas.\n\nAuthor summaryRespiratory tract infections are one of the leading causes of death worldwide. Populations in underdeveloped countries are the most affected, especially children under 5 years of age. Among the pathogens responsible for these infections, bacteria and viruses are the most identified. In poor countries, laboratory diagnosis can only be done in urban areas. They are generally based on bacteriological, immunological or molecular biology techniques. The concept of POC is not developed in underdeveloped countries. Its existence would have made it possible to carry out RDTs to confirm the clinicians diagnosis and allow rapid management of the patient. In the current situation, the time required to achieve results is often very long for patients. In this study, we sought to demonstrate the significant contribution of the FilmArray respiratory panel in the management of respiratory tract infections in rural areas. We also wanted to reduce the time it takes to deliver results in order to improve patient care. This dispositif was integrated in a field POC which was implemented in Niakhar since 2015, in order to improve the management of emerging diseases. The FilmArray respiratory panel gave us the opportunity to investigate the causes of respiratory tract infections in this area. For each patient, we systematically target 20 pathogens, including 17 viruses and 3 bacteria, with a single multiplex PCR. One of the main results of this study is that children under 5 years of age are the most affected by respiratory tract infections. Then we noted a lack of consultation among adults that could be explained by the banalization of respiratory problems or a preference for traditional care. The fact that children under 5 years of age are the most affected could also serve as a basis for implementing vaccination programmes directly targeting the most vulnerable age groups. It should be noted that for 51% of patients, the result of the diagnosis was negative. It would appear that some pathogens responsible for respiratory tract infections are not targeted by the multiplex PCR. Thus, it would be necessary to screen these pathogens in order to integrate them into a panel that would cover the most pathogens in circulation in this area.

molecular biology↗

bioRxiv2017

African Nonhuman Primates Are Infected With The Yaws Bacterium Treponema pallidum subsp. pertenue

Treponema pallidum subsp. pertenue (TPE) is the causative agent of yaws. The disease was subject to global eradication efforts in the mid 20th century but reemerged in West Africa, Southern Asia, and the Pacific region. Despite its importance for eradication, detailed data on possible nonhuman disease reservoirs are missing. A number of African nonhuman primates (NHPs) have been reported to show skin ulcerations suggestive of treponemal infection in humans. Furthermore antibodies against Treponema pallidum (TP) have been repeatedly detected in wild NHP populations. While genetic studies confirmed that NHPs are infected with TP strains, subspecies identification was only possible once for a strain isolated in 1966, pinpointing the involvement of TPE. We therefore collected a number of recently isolated simian TP strains and determined eight whole genome sequences using hybridization capture or long-range PCR combined with next-generation sequencing. These new genomes were compared with those of known human TP isolates. Our results show that naturally occurring simian TP strains circulating in three African NHP species all cluster with human TPE strains and show the same genomic structure as human TPE strains. These data indicate that humans are not the exclusive host for the yaws bacterium and that a One Health approach is required to achieve sustainable eradication of human yaws.

microbiology↗