BackgroundSub-Saharan Africa is undergoing an epidemiological transition from a predominance of infectious diseases to non-communicable and lifestyle related conditions. However, the pace of this transition and the pattern of disease epidemiology are uneven between affluent urban and rural poor populations. To address this question for a remote rural region located in the central African rainforest region of Gabon, this study was conducted to assess reasons for health care attendance and to characterize the epidemiology of malaria and other major infectious diseases for the department of Tsamba Magotsi.MethodsMajor causes for health care attendance were collected from local hospital records. Cross sectional population based surveys were performed for the assessment of local malaria epidemiology. Pregnant women attending antenatal care services were surveyed as a sentinel population for the characterization of chronic viral and parasitic infections in the community.ResultsInfectious diseases were responsible for 71% (7469) of a total of 10,580 consultations at the formal health care sector in 2010. Overall, malaria – defined by clinical syndrome – remained the most frequent cause for health care attendance. A cross sectional malaria survey in 840 asymptomatic individuals residing in Tsamba Magotsi resulted in a Plasmodium spp. infection prevalence of 37%. The infection rate in 2–10 year old asymptomatic children – a standard measure for malaria endemicity – was 46% (100 of 217) with P. falciparum as predominant species (79%). Infection with other plasmodial species (P. ovale and P. malariae) presented most commonly as coinfections (23.2%). Prevalence of HIV, HBV, and syphilis were 6.2, 7.3, and 2.5%, respectively, in cross-sectional assessments of antenatal care visits of pregnant women. Urogenital schistosomiasis and the filarial pathogens Loa loa and Mansonella perstans are highly prevalent chronic parasitic infections affecting the local population.ConclusionsDespite major improvements in the accessibility of Tsamba Magotsi over the past decade the epidemiological transition does not appear to have majorly changed on the spectrum of diseases in this rural Gabonese population. The high prevalence of Plasmodium infection indicates a high burden of malaria related morbidity. Infectious diseases remain one of the most important health issues and further research activities in the field of tropical medicine and infectious diseases could help improve health care for the local population.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-017-4045-x) contains supplementary material, which is available to authorized users.

Plasmodium falciparum resistance to chloroquine has been described in many parts of the world particularly in Africa where malaria is endemic. High levels of chloroquine resistance in our study area, Lambarene-Gabon, has led to the use of an alternative regimen for treatment and prevention of P. falciparum infection. In this study, we examined the in vitro chloroquine sensitivity of 15 isolates from this area and assessed the prevalence of a putative chloroquine resistance associated Pfmdr1 polymorphism (Asn86Tyr) using a novel allele-specific polymerase chain reaction (PCR). Only 4 of the isolates examined were chloroquine sensitive. The allele-specific PCR shows that all 15 isolates carried the variant (86Tyr) codon. Eleven of these were resistant to chloroquine suggesting a 73% agreement between chloroquine resistance phenotype and the point mutation. This molecular marker was examined in a further 73 Gabonese isolates, where 58 (79.5%) showed 86Tyr and 15 (20.5%) showed 86Asn. In all, 4 (4.5%) of the 88 isolates assessed carry both mutant and wild-type codons, suggesting mixed parasite populations. The incomplete agreement found between chloroquine resistance phenotype and Pfmdr1 (86Tyr) polymorphism would support the view that other genetic factors as well as Pfmdr1 may be involved in chloroquine resistance. While our results suggest a high prevalence of 86Tyr polymorphism in Lambarene, the Asp1246Tyr polymorphism (a point mutation which to date has only been associated with South American P. falciparum) seems to be absent in our study area.

HLA class II DRB1-DQA1-DQB1 haplotypic polymorphism was determined in 120 Liberian and 230 Gabonese individuals. In our study groups, the number of allelic variants observed for each locus was similar to that found in non-African populations. However, 39 novel haplotypes and several yet unrecognized DRB1-DQA1 and DQA1-DQB1 combinations were identified. The extent of HLA-haplotypic variability in Africans appears to result from the high degree of allele combinations rather than from allelic polymorphism.