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Background: Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bloodsucking parasite that co-evolved with their human hosts over thousands of years, thus providing a valuable source of information to reconstruct the human migration. Pediculosis due to head lice occurred each year throughout the world and several pathogenic bacteria, which are usually associated with body lice, are increasingly detected in them. In Gabon, where this pediculosis is still widespread, there is a lack of data on genetic diversity of head lice and their associated bacteria. Methods: This study aimed to investigate the phylogeny of head lice collected in Gabon and their associated bacteria, using molecular tools. Between 26 March and 11 April 2018, 691 head lice were collected from 86 women in Franceville. We studied the genetic diversity of these lice based on the cytochrome b gene, then we screened them for DNA of Bartonella quintana, Borrelia spp., Acinetobacter spp., Yersinia pestis, Rickettsia spp., R. prowazekii, Anaplasma spp. and C. burnetii, using real time or standard PCR and sequencing. Results: Overall 74.6% of studied lice belonged to Clade A, 25.3% to Clade C and 0.1% to Clade E. The phylogenetic analysis of 344 head lice yielded 45 variable positions defining 13 different haplotypes from which 8 were novel. Bacterial screening revealed the presence of Borrelia spp. DNA in 3 (0.4%) of 691 head lice belonging to Clade A and infesting one individual. This Borrelia is close to B. theileri (GenBank: MN621894). Acinetobacter spp. DNA has been detected in 39 (25%) of the 156 screened lice; of these 13 (8.3%) corresponded to A. baumannii. Acinetobacter nosocomialis (n = 2) and A. pittii (n = 1) were also recorded. Conclusions: To of our knowledge, this study is the first to investigate the genetic diversity of head lice from Gabon. It appears that Clade C is the second most important clade in Gabon, after Clade A which is known to have a global distribution. The detection of Borrelia spp. DNA in these lice highlight the potential circulation of these bacteria in Gabon. [ABSTRACT FROM AUTHOR]

Background: Artesunate-amodiaquine (AS-AQ) and artemether-lumefantrine (AL) are first- and second-line treatments for uncomplicated Plasmodium falciparum malaria in Gabon. AL remains highly efficacious, but its widespread use has led to molecular selection of the NFD haplotype on Pfmdr1 and K76 in Pfcrt. In this study, plasmodial infection characteristics and the distribution of the Pfmdr1 and Pfcrt genotypes involved in reduced efficacy of artemisininbased combination therapy (ACT) were investigated in four Gabonese localities. Methods: A cross-sectional study was conducted in the paediatric units of rural (Lastourville and Fougamou), semiurban (Koula-Moutou) and urban (Franceville) areas. Malaria was diagnosed with the rapid diagnostic test Optimal-IT® and confirmed by blood smear. Pfmdr1 codons 86, 184 and 1246 and Pfcrt codon 76 were genotyped by PCR-RFLP and sequencing. Results: Among 1129 included children, the prevalence of plasmodial infection was 79.5 % at Lastourville, 53.6 % at Fougamou, 36.1 % at Koula-Moutou, and 21.2 % at Franceville. The prevalence was significantly higher among children over 60 months of age in both semi-urban (p = 0.01) and urban (p = 0.004) areas. The prevalence of Pfmdr1 wild-type N86 differed significantly between Lastourville (57.8 %) and Koula-Moutou (45.4 %) (p = 0.039). No difference in 184F-carrying parasites was found between Lastourville (73.8 %), Fougamou (81.6 %), Koula-Moutou (83.2 %), and Franceville (80.6 %) (p = 0.240). The prevalence of wild-type D1246 was significantly different between Lastourville (94.1 %), Koula-Moutou (85.6 %) and Franceville (87.3 %) (p = 0.01). The frequency of wild-type K76 was not significantly different across the four sites: Lastourville (16.5 %), Fougamou (27.8 %), Koula-Moutou (17.4 %), and Franceville (29.4 %) (p = 0.09). The mixed genotypes were only found in Lastourville and Franceville. The NFD, YFD and NYD haplotypes were mainly Lastourville (46.6, 25.8, 14.0 %), Fougamou (45.5, 9.1, 42.4 %), Koula-Moutou (35, 6.7, 40.4 %), and Franceville (40.0, 16.0, 32.0 %). Conclusion: This study shows an increase in the prevalence of childhood plasmodial infection in Gabon according to the low socio-economic level, and a high frequency of markers associated with AL treatment failure. Close monitoring of ACT use is needed. [ABSTRACT FROM AUTHOR]

Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children <15 years of age in 4 areas of Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afebrile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/60 children), respectively. Prevalence differed among febrile children living in areas that are urban (Franceville, 1.3% [1/77]), semiurban (Koulamoutou, 2.1% [3/141]), and rural (Lastourville, 11.2% [15/134]; Fougamou, 39.7% [23/58]). Furthermore, in a rural area (Fougamou), R. felis was significantly more prevalent in febrile (39.7% [23/58]) than afebrile children (5.0% [1/20]). Additional studies are needed to better understand the pathogenic role of R. felis in this part of the world. [ABSTRACT FROM AUTHOR]

The epidemiology of febrile illness etiologies is under-explored in resource-poor settings. Establishing a local repertory of microorganisms circulating in blood of febrile and afebrile people is important for physicians. Blood was collected from 428 febrile and 88 afebrile children in Makokou (Gabon) and analyzed using polymerase chain reaction. Plasmodium spp. were the pathogens, which were most detected in febrile children (69.6%; 298/428) and in afebrile children (31.8%; 28/88) ( P < 0.0001). Plasmodium falciparum was the most prevalent species in both febrile and afebrile children (66.8% and 27.3%, respectively). No differences were observed between febrile and afebrile children for Plasmodium malariae and Plasmodium ovale (8.2% versus 10.2% and 3.3% versus 3.4%, respectively). Triple infection with P. falciparum , P. malariae , and P. ovale was also detected in 1% of febrile children (4/428). Filariasis due to Mansonella perstans was detected in 10 febrile patients (2.3%), whereas Loa loa was detected in both febrile and afebrile children (1.4% and 2.3%, respectively). Bacterial DNA was detected in only 4.4% (19/428) of febrile children, including 13 (68.4%) who were coinfected with at least one Plasmodium species. These were Haemophilus influenzae (1.6%, 7/428), Streptococcus pneumoniae and Staphylococcus aureus (1.2%, 5/428), and Rickettsia felis (0.9%, 4/428). Coxiella burnetii , Bartonella spp., Borrelia spp., Tropheryma whipplei , Anaplasma spp., Leptospira spp., Streptococcus pyogenes , and Salmonella spp. were not detected. This study also highlights the over-prescription and the overuse of antibiotics and antimalarials. Overall, malaria remains a major health problem in Makokou. Malaria control measures must be reconsidered in this region.

Background: Like other tropical African countries, Gabon is afflicted by many parasitic diseases, including filariases such as loiasis and mansonellosis. This study aimed to assess the prevalence of these two filarial diseases in febrile and afebrile children using quantitative real-time PCR and standard PCR assays coupled with sequencing., Methodology/principal Findings: DNA from blood specimens of 1,418 Gabonese children (1,258 febrile and 160 afebrile) were analyzed. Overall, filarial DNA was detected in 95 (6.7%) children, including 67 positive for M. perstans (4.7%), which was the most common. M. perstans was detected in 61/1,258 febrile children (4.8%) and 6/160 afebrile children (3.8%, P = 0.6). Its prevalence increased statistically with age: 3.5%, 7.7% and 10.6% in children aged ≤ 5, 6-10 and 11-15 years, respectively. M. perstans prevalence was significantly higher in Koulamoutou and Lastourville (12% and 10.5%, respectively) than in Franceville and Fougamou (2.6% and 2.4%, respectively). Loa loa was detected in seven febrile children including one co-infection with M. perstans. Finally, 21 filarial DNA positive were negative for M. perstans and Loa loa, but ITS sequencing could be performed for 12 and allowed the identification of a potential new species of Mansonella provisionally called "DEUX". Mansonella sp. "DEUX" was detected only in febrile children., Conclusions/significance: Further study should be performed to characterize Mansonella sp. "DEUX" and evaluate the clinical significance of mansonellosis in humans.

Malaria was considered as the main cause of fever in Africa. However, with the roll back malaria initiative, the causes of fever in Africa may change. This study aimed to evaluate the prevalence of bacteria and Plasmodium spp. in febrile and afebrile (controls) children from Franceville, Gabon. About 793 blood samples from febrile children and 100 from controls were analyzed using polymerase chain reaction (PCR) coupled with sequencing. Plasmodium spp. was the microorganism most detected in febrile (74.5%, 591/793) and controls (13%, 13/100), P < 0.0001. Its coinfection with bacteria was found only in febrile children (P = 0.0001). Staphylococcus aureus was the most prevalent bacterium in febrile children (2.8%, 22/793) and controls (3%, 3/100). Eight cases of Salmonella spp. (including two Salmonella enterica serovar Paratyphi) and two of Streptococcus pneumoniae were found only among febrile children. Borrelia spp. was found in 2 controls while Rickettsia felis was detected in 10 children (in 8 febriles and 2 afebriles). No DNA of other targeted microorganisms was detected. Plasmodium spp. remains prevalent while Salmonella spp., Staphylococcus aureus, and Streptococcus pneumoniae were common bacteria in Gabon. Two fastidious bacteria, Rickettsia felis and Borrelia spp., were found. Inclusion of controls should improve the understanding of the causes of fever in sub-Saharan Africa., (© The American Society of Tropical Medicine and Hygiene.)

Background: To date, 6 tick-borne rickettsiae pathogenic for humans are known to occur in Africa and 4 of them were first identified in ticks before being recognized as human pathogens., Results: We examined 33 and 5 Amblyomma tholloni ticks from African elephants in the Central African Republic and Gabon, respectively, by PCR amplification and sequencing of a part of gltA and ompA genes of the genus Rickettsia. The partial sequences of gltA and ompA genes detected in tick in Gabon had 99.1% similarity with those of R. heilongjiangensis and 97.1% with those of Rickettsia sp. HL-93 strain, respectively. The partial gltA and ompA gene sequences detected in tick in the Central African Republic were 98.9% and 95.1% similar to those of Rickettsia sp. DnS14 strain and R. massiliae, respectively. Phylogenetic analysis showed Rickettsia sp. detected in Gabon clusters with R. japonica and R. heilongjiangensis in a phylogenetic tree based on the partial gltA and ompA genes. The genotype of the Rickettsia sp. detected in the Central African Republic is close to those of R. massiliae group in the phylogenetic tree based on partial gltA gene sequences, and distantly related to other rickettsiae in the tree based on partial ompA gene., Conclusion: The degrees of similarity of partial gltA and ompA genes with recognized species indicate the rickettsiae detected in this study may be new species although we could only study the partial sequences of 2 genes regarding the amount of DNA that was available. We propose the Rickettsia sp. detected in Gabon be provisionally named "Rickettsia sp. stain Davousti" and Rickettsia sp. detected in the Central African Republic be named "Rickettsia sp. strain Uilenbergi".

We detected Rickettsia felis DNA in Ctenocephalides felis and Bartonella quintana DNA in 3 Pulex irritans fleas taken from a pet Cercopithecus cephus monkey in Gabon, sub-Saharan Africa. This is the first report of B. quintana in the human flea.