Biology subjects

Fenollar, F.

Publications and source records attributed to Fenollar, F..

9 recordsLinked to original sources

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↗

bioRxiv2026

Description of Rickettsia senegalensis sp. nov.: a new Rickettsia species detected worldwide

Members of the genus Rickettsia are widespread obligate intracellular bacteria with high medical and veterinary relevance. While Rickettsia senegalensis was previously isolated from cat fleas, Ctenocephalides felis, in Senegal, a comprehensive polyphasic characterization is required for its formal taxonomic validation. This study aims to provide the first detailed phenotypic, ultrastructural, and genomic characterization of the type strain PU01-02. Cultivation assays demonstrated that strain PU01-02 grows aerobically in XTC-2, SF9, and LD652 cell lines at 28 {degrees}C in a CO2-free atmosphere. Ultrastructural examination via scanning electron microscopy using a backscattered electron detector confirmed its free cytoplasmic localization and a typical rickettsial morphology characterized by rod-shaped cells approximately 1.5 {micro}m in length and 0.3 {micro}m in width. Whole-genome sequencing yielded a 1.62-Mb genome with a G+C content of 33.2%, and three plasmids were detected. Genomic analyses confirmed its status as a distinct species, placing it within the transitional Rickettsia group, specifically inside the Rickettsia felis cluster. A review of epidemiological data revealed that rickettsial genes identical to those of R. senegalensis had already been identified in several hematophagous arthropods, including fleas and ticks parasitizing various hosts such as cats, dogs, opossums, and rodents worldwide. It has also been detected in cat tissues, suggesting a potential host-pathogen association. Based on these comprehensive characterization data, we formally propose Rickettsia senegalensis sp. nov. as a new species, with PU01-02 (= CSUR R184 = DSM 28250) as the type strain. RepositoriesThe genome sequence of Rickettsia senegalensis sp. nov. strain PU01-02T has been deposited in GenBank under accession number JBVYTQ000000000, and the rrs, gltA, ompB and sca4 gene sequences under accession numbers KF666476, KF666472, KF666470, KF666474, respectively. The plasmid accession numbers are PZ272915, PZ272916, and PZ272917, for pRS01, pRS02 and pRS03, respectively.

microbiology↗

bioRxiv2026

Silent Footprints of Ebolavirus in the Forest: Serological Clues from Wild Non-Human Primates in the Democratic Republic of Congo

Filoviruses, particularly Ebola virus (EBOV), remain a major public health concern in Central Africa. However, their circulation in wildlife during inter-epidemic periods remains poorly documented. Non-human primates (NHPs) may serve as ecological sentinels of viral dynamics at human-forest interfaces, yet surveillance is constrained by the limitations of invasive sampling. We conducted a non-invasive investigation of EBOV exposure in free-ranging NHPs from the Mabali Forest Reserve (Equateur Province, Democratic Republic of Congo) for Ebola virus disease. A total of 630 fecal samples were collected and screened for active infection by PCR targeting the EBOV nucleoprotein gene; all samples tested negative. Molecular identification of host species was achieved in 569 samples (90.3%). Fecal serology using an automated capillary western blot platform (JESS), targeting EBOV nucleoprotein, glycoprotein and viral protein 40 antigens, identified four seropositive individuals (0.70%), including two Cercopithecus ascanius and two C. wolfi. The detection of discrete immunoreactive bands consistent with EBOV-specific antibodies suggests prior exposure despite the absence of active outbreaks. These findings provide the first serological evidence compatible with EBOV exposure in these two Cercopithecus species and support the hypothesis of low-level or cryptic viral circulation in forest ecosystems. The study highlights the feasibility and value of fecal serology as a non-invasive One Health surveillance tool for monitoring zoonotic pathogens at wildlife-human interfaces.

microbiology↗

bioRxiv2024

Circulation of Klebsiella pneumoniae strains between the termites, chimpanzees and humans

The emergence and multiplication of multi-resistant microbes is becoming a major concern in medicine and scientific research, requiring an integrated, global approach to prevent their spread and develop new therapeutic solutions. Klebsiella pneumoniae can cause a variety of infections. It has several distinctive features, such as extended-spectrum beta-lactamase (ESBL) production and frequency in hospital-acquired infections, which set it apart from other bacteria as Pseudomonas aeruginosa or staphylococci and make it of particular concern in the clinical setting. In this study, we worked on four strains of multidrug-resistant K. pneumoniae isolated from different patients at Fann Hospital in Dakar, Senegal. Whole genomes were compared them with those of nine K. pneumoniae isolates from chimpanzees (CHZ) and six from termites (T_NSC) from our previous study. The comparison revealed two major genetic groups: three human strains were virtually identical to those found in three chimpanzees and four genomes extracted from termites regularly consumed by chimpanzees were identical to five K. pneumoniae strains from chimpanzees. In silico, we identified the resistance genes and their corresponding families from each isolate, then genotyped them before comparing them with other isolates stored in the Institute Pasteur database. These strains have never been previously identified in Senegal. It has been shown here that multiresistant K. pneumoniae strains circulate between chimpanzees and termites and between chimpanzees and humans. Furthermore, these strains, often associated with nosocomial infections, have been identified and genotyped outside Senegal. Although similar strains have been already identified in tropical countries and in different intensive care units throughout the world, we hypothesize that they may originate from termite-chimpanzee ecosystem.

bioinformatics↗

bioRxiv2022

Evidence of antibodies against SARS-CoV-2 in wild mustelids from Brittany (France)

In the French region of Brittany, mainly in the department of the Cotes dArmor, during the first semester of 2021, seropositivity for SARS-CoV-2 was detected in five wild mustelids out of 32 animals tested. Anti-SARS-CoV-2 IgG against at least four out of five recombinant viral proteins (S1 receptor binding domain, nucleocapsid, S1 subunit, S2 subunit and spike) were detected using automated western blot technique in three martens (Martes martes) and two badgers (Meles meles). An ELISA test also objectified seropositivities. Although the 171 qPCRs carried out on samples from the 33 mustelids were all negative, these preliminary results (observational study) nevertheless bear witness to infections of unknown origin. The epidemiological surveillance of Covid-19 in wildlife must continue, in particular with the tools of efficient serology.

microbiology↗

bioRxiv2020

Stool serology: development of a non-invasive immunological method for the detection of Enterovirus-specific antibodies in Congo gorilla feces

The incidence of poliovirus has significantly reduced by as much as 99.9% globally. Alongside this, however, vaccine-associated paralytic poliomyelitis has emerged. Recently, a new recombinant virus (Enterovirus C/Poliovirus) was identified in humans working as eco-guards and in gorillas in Democratic Republic of Congo, including one gorilla with polio-like sequelae. A strain of this recombinant virus (Ibou002) was also isolated from gorilla faeces. In order to assess the potential role of poliovirus infection, we have developed and optimised a protocol, based on the lyophilisation and solubilisation of small volumes of stool extracts, to detect specific antibodies. First, total immunoglobulins was detected in the concentrated stool extracts. Specific antibodies were then detected in 4/16 gorilla samples and 2/3 human samples by western blot using both the polio vaccine antigen and the Ibou002 antigen and by ELISA using the polio vaccine antigen. Humoral responses were greater with the Ibou002 antigen. We therefore suggest that this recombinant virus could lead to a polio-like disease in the endangered western lowland gorilla. The development of a non-invasive method to detect microorganism-specific immunoglobulins from faecal samples opens up new perspectives for the exploration of humoral responses of pathogens in animals and a greater understanding of zoonotic infectious diseases.

microbiology↗

bioRxiv2019

Development of a multiplexed qPCRs-based approach for the diagnosis of Dirofilaria immitis, D. repens, Acanthocheilonema reconditum and the others filariosis

BackgroundThe frequent canine filariosis are caused by zoonotic filarial nematodes called Dirofilaria immitis, D. repens and Acanthocheilonema reconditum (Spirurida: Onchocercidae). The absence of reliable diagnostic tools to diagnose and discriminate between these infections as well as their different forms constitutes a major obstacle to their control. The serological diagnosis of heartworm disease has recently shown both sensitivity and specificity problems. FindingsHerein, we developed and set up a novel molecular approach for an improved detection of the occult and non-occult filarioses, especially those caused by A. reconditum, D. immitis and D. repens as well as their differential diagnosis based on qPCRs assays. This approach designated the "Combined multiplex approach", proceeds as follows: Filaria and wolbachia identification using the newly customized 28S-based pan-filarial and 16S-based pan-wolbachia qPCRs, respectively, followed by the fast typing method of positive samples using the triplex qPCR targeting A. reconditum, D. immitis and D. repens, and a duplex qPCR targeting Wolbachia of D. immitis and that of D. repens. The analytical sensitivity of the newly qPCR systems was confirmed by the detection limit of wolbachia and filaria DNA ranged from 5E-1 to 1.5E-4 mf/ml of blood with an R{superscript 2} higher than 0.99, Cohens Kappa agreement ranged from 0.98 to 1. The approach was complemented by a pan-filarial COI and pan-Wolbachia ftsZ PCR for the identification of other filarial parasites and their Wolbachia, respectively. When tested on clinical samples, the results are as follows: 29.2 % (49/168) tested positive to at least filariae or wolbachiae DNA. 19 samples of them tested positive for filarial DNA, 9 for wolbachia DNA and 21 for both. Filarial species and Wolbachia genotype were also identified by the combined multiplex approach from all the positive samples. The single DNA of D. immitis was identified in 12 samples, D. repens in 7, and A. reconditum in 15 samples, the co-infection was observed in 5 samples, 4 for both Dirofilaria and one harbored the three species. Therefore, 22 samples were positive for Wolbachia endosymbiont of D. immitis, 3 for that of D. repens and 5 for both genotypes. A newly duplex qPCR developed for the differential diagnosis of heartworm and French heartworm (Angiostrongylus vasorum) was successfully validated in vitro. However, no DNA of this latter was detected in canine blood samples used in this study. The immunochromatographic test for dirofilariasis antigen during evaluation before and after thermal pretreatment of sera showed substantial agreement (K=0.6) and weak agreement (K=0.15), respectively. ConclusionThe proposed molecular tool targeting filarial genes and associated Wolbachia genes is a reliable tool for the exploration and diagnosis of occult and non-occult canine filariasis. We believe that the current diagnosis of heartworm based on antigen detection should be always confirmed by qPCR-based essays; the heat-pretreatment of sera is useless and strongly discouraged.

molecular biology↗

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

IRF4 haploinsufficiency in a family with Whipples disease

The pathogenesis of Whipples disease (WD) remains largely unknown, as WD strikes only a very small minority of the individuals infected with Tropheryma whipplei (Tw). Asymptomatic carriage of Tw is less rare. We studied a large multiplex French kindred, containing four otherwise healthy WD patients (mean age: 76.7 years) and five healthy carriers of Tw (mean age: 55 years). We used a strategy combining genome-wide linkage analysis and whole-exome sequencing to test the hypothesis that WD is inherited in an autosomal dominant (AD) manner, with age-dependent incomplete penetrance. WD was linked to 12 genomic regions covering 27 megabases in the four patients. These regions contained only one very rare non-synonymous variation: the R98W variant of IRF4. The five Tw carriers were heterozygous for R98W. Interferon regulatory factor 4 (IRF4) is a transcription factor with pleiotropic roles in immunity. We showed that R98W was a loss-of-function allele, like only five other exceedingly rare IRF4 alleles of a total of 39 rare and common non-synonymous alleles tested. Furthermore, heterozygosity for R98W led to a distinctive pattern of transcription in leukocytes following stimulation with BCG or Tw. Finally, we found that IRF4 had evolved under purifying selection and that R98W was not dominant-negative, suggesting that the IRF4 deficiency in this kindred was due to haploinsufficiency. Overall, haploinsufficiency at the IRF4 locus selectively underlies WD in this multiplex kindred. This deficiency displays AD inheritance with incomplete penetrance, and chronic carriage probably precedes WD by several decades in Tw-infected heterozygotes.

immunology↗