Alpha Kabinet Keita

Intrafamilial circulation of Tropheryma whipplei, France.

High prevalence within families might reflect a specific immune condition.

Tropheryma whipplei: A Common Bacterium in Rural Senegal

Background Tropheryma whipplei is known as the cause of Whipples disease, but it is also an emerging pathogen, detected in stool, that causes various chronic localized infections without histological digestive involvement and is associated with acute infections, including gastroenteritis and bacteremia. Methods/Principal Findings We conducted a study in 2008 and 2009 using 497 non-diarrheic and diarrheic stool samples, 370 saliva samples, 454 sera samples and 105 samples obtained from water samples in two rural Sine-Saloum villages (Dielmo and Ndiop) in Senegal. The presence of T. whipplei was investigated by using specific quantitative PCR. Genotyping was performed on positive samples. A serological analysis by western blotting was performed to determine the seroprevalence and to detect seroconversion. Overall, T. whipplei was identified in 31.2% of the stool samples (139/446) and 3.5% of the saliva samples (13/370) obtained from healthy subjects. The carriage in the stool specimens was significantly (p<10−3) higher in children who were between 0 and 4 years old (60/80, 75%) compared to samples obtained from individuals who were between 5 to 10 years old (36/119, 30.2%) or between 11 and 99 years old (43/247, 17.4%). The carriage in the stool was also significantly more common (p = 0.015) in subjects with diarrhea (25/51, 49%). We identified 22 genotypes, 16 of which were new. Only one genotype (#53) was common to both villages. Among the specific genotypes, one (#52) was epidemic in Dielmo (15/28, 53.4%, p<10−3) and another (#49) in Ndiop (27.6%, p = 0.002). The overall seroprevalence was estimated at 72.8% (291/400). Seroconversion was detected in 66.7% (18/27) of children for whom PCR became positive in stools between 2008 and 2009. Conclusions/Significance T. whipplei is a common bacterium in the Sine-Saloum area of rural Senegal that is contracted early in childhood. Epidemic genotypes suggest a human transmission of the bacterium.

Molecular evidence for the presence of Rickettsia Felis in the feces of wild-living African apes.

Background Rickettsia felis is a common emerging pathogen detected in mosquitoes in sub-Saharan Africa. We hypothesized that, as with malaria, great apes may be exposed to the infectious bite of infected mosquitoes and release R. felis DNA in their feces. Methods We conducted a study of 17 forest sites in Central Africa, testing 1,028 fecal samples from 313 chimpanzees, 430 gorillas and 285 bonobos. The presence of rickettsial DNA was investigated by specific quantitative real-time PCR. Positive results were confirmed by a second PCR using primers and a probe targeting a specific gene for R. felis. All positive samples were sequenced. Results Overall, 113 samples (11%) were positive for the Rickettsia-specific gltA gene, including 25 (22%) that were positive for R. felis. The citrate synthase (gltA) sequence and outer membrane protein A (ompA) sequence analysis indicated 99% identity at the nucleotide level to R. felis. The 88 other samples (78%) were negative using R. felis-specific qPCR and were compatible with R. felis-like organisms. Conclusion For the first time, we detected R. felis in wild-living ape feces. This non invasive detection of human pathogens in endangered species opens up new possibilities in the molecular epidemiology and evolutionary analysis of infectious diseases, beside HIV and malaria.

Looking for Tropheryma whipplei Source and Reservoir in Rural Senegal

Tropheryma whipplei, the bacterium linked to Whipples disease, is involved in acute infections and asymptomatic carriage. In rural Senegal, the prevalence of T. whipplei is generally high but is not homogeneous throughout households in the same village. We studied environmental samples collected in two Senegalese villages and conducted the survey to investigate the difference between households. Overall, the comparison between five households with very high T. whipplei prevalence and three households without any registered cases showed that the only difference was the presence of toilets in the latter (1/5 versus 3/3; P = 0.01423). Among the 1,002 environmental specimens (including domestic and synanthropic animals and dust sampled in households) tested for T. whipplei DNA, only four specimens were slightly positive. Humans are currently the predominant identified reservoir and source of T. whipplei in these populations. Limited access to toilets and exposure to human feces facilitate the fecal-oral transmission of T. whipplei.

Tropheryma whipplei as a commensal bacterium

Tropheryma whipplei is the bacterial agent of the well-known and rare Whipples disease, mainly observed among Caucasians. This bacterium has recently been involved in other chronic and acute infections. For a long time, the only known source of the bacterium was patients with Whipples disease; however, thanks to the advent of molecular biology, T. whipplei has now been detected in specimens from healthy individuals, mainly in stool and saliva samples. The prevalence of carriage depends on several factors, such as age, exposure and geographical area, reaching 75% in stool specimens from children less than 4 years old in rural Africa. T. whipplei is a commensal bacterium that only causes Whipples disease in a subset of individuals, probably those with a still-uncharacterized specific immunological defect.

High Prevalence of Tropheryma whipplei in Lao Kindergarten Children

Background Tropheryma whipplei is a bacterium commonly found in feces of young children in Africa, but with no data from Asia. We estimated the prevalence of T. whipplei carriage in feces of children in Lao PDR (Laos). Methods/Principal Findings Using specific quantitative real-time PCR, followed by genotyping for each positive specimen, we estimated the prevalence of T. whipplei in 113 feces from 106 children in Vientiane, the Lao PDR (Laos). T. whipplei was detected in 48% (51/106) of children. Those aged ≤4 years were significantly less frequently positive (17/52, 33%) than older children (34/54, 63%; p< 0.001). Positive samples were genotyped. Eight genotypes were detected including 7 specific to Laos. Genotype 2, previously detected in Europe, was circulating (21% of positive children) in 2 kindergartens (Chompet and Akad). Genotypes 136 and 138 were specific to Chompet (21% and 15.8%, respectively) whereas genotype 139 was specific to Akad (10.55%). Conclusions/Significance T. whipplei is a widely distributed bacterium, highly prevalent in feces of healthy children in Laos. Further research is needed to identify the public health significance of this finding.

Tropheryma whipplei as a Cause of Epidemic Fever, Senegal, 2010-2012.

Findings suggest that the bacterium has role in febrile episodes, is contagious, and has an epidemic character.

Co-circulation of Plasmodium and Bacterial DNAs in Blood of Febrile and Afebrile Children from Urban and Rural Areas in Gabon.

Malaria is considered to be the most common etiology of fever in sub-Saharan Africa while bacteremias exist but are under assessed. This study aimed to assess bacteremias and malaria in children from urban and rural areas in Gabon. DNA extracts from blood samples of 410 febrile and 60 afebrile children were analyzed using quantitative polymerase chain reaction. Plasmodium spp. was the microorganism most frequently detected in febrile (78.8%, 323/410) and afebrile (13.3%, 8/60) children, (P < 0.001). DNA from one or several bacteria were detected in 15 febrile patients (3.7%) but not in the controls (P = 0.1). This DNA was more frequently detected as co-infections among febrile children tested positive for Plasmodium (4.6%, 15/323) than in those tested negative for Plasmodium (0%, 0/87; P = 0.04). The bacteria detected were Streptococcus pneumoniae 2.4% (10/410), Staphylococcus aureus 1.7% (7/410), Salmonella spp. 0.7% (3/410), Streptococcus pyogenes 0.2% (1/410) and Tropheryma whipplei 0.2% (1/410) only in febrile children. Coxiella burnetii, Borrelia spp., Bartonella spp., Leptospira spp., and Mycobacterium tuberculosis were not observed. This paper reports the first detection of bacteremia related to T. whipplei in Gabon and shows that malaria decreases in urban areas but not in rural areas. Co-infections in febrile patients are common, highlighting the need to improve fever management strategies in Gabon.

Survey of Ebola Viruses in Frugivorous and Insectivorous Bats in Guinea, Cameroon, and the Democratic Republic of the Congo, 2015–2017

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015–2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2–37 (0.05%–0.92%) bats were seropositive for Zaire and 0–30 (0%–0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.