Chikungunya virus infection, Brazzaville, Republic of Congo, 2011.
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ABSTRACT:
SUBMITTER: Mombouli JV
PROVIDER: S-EPMC3810930 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundChikungunya is an Aedes -borne disease characterised by febrile arthralgia and responsible for massive outbreaks. We present a prospective clinical cohort study and a retrospective serological study relating to a CHIK outbreak, in the Republic of Congo in 2011.Methodology and findingsWe analysed 317 suspected cases, of which 308 (97.2%) lived in the city of Brazzaville (66.6% in the South area). Amongst them, 37 (11.7%) were CHIKV+ve patients (i.e., biologically confirmed by a real-time RT-PCR assay), of whom 36 (97.3%) had fever, 22 (66.7%) myalgia and 32 (86.5%) arthralgia. All tested negative for dengue. The distribution of incident cases within Brazzaville districts was compared with CHIKV seroprevalence before the outbreak (34.4% in 517 blood donors), providing evidence for previous circulation of CHIKV. We applied a CHIK clinical score to 126 patients recruited within the two first day of illness (including 28 CHIKV+ves (22.2%)) with sensitivity (78.6%) and specificity (72.4%) values comparing with those of the referent study in Reunion Island. The negative predictive value was high (92%), but the positive predictive value (45%) indicate poor potential contribution to medical practice to identify CHIKV+ve patients in low prevalence outbreaks. However, the score allowed a slightly more accurate follow-up of the evolution of the outbreak than the criterion "fever+arthralgia". The complete sequencing of a Congolase isolate (Brazza_MRS1) demonstrated belonging to the East/Central/South African lineage and was further used for producing a robust genome-scale CHIKV phylogenetic analysis.Conclusions/significanceWe describe the first Chikungunya outbreak declared in the Republic of Congo. The seroprevalence study conducted amongst blood donors before outbreak provided evidence for previous CHIKV circulation. We suggest that a more systematic survey of the entomological situation and of arbovirus circulation is necessary in Central Africa for better understanding the environmental, microbiological and sociological determinants of emergence.
| S-EPMC4277398 | biostudies-literature
Project description:BACKGROUND:Malaria transmission-blocking anti-malarial drugs, such as primaquine, offers an effective strategy for reducing the incidence of falciparum malaria. However, this drug induces haemolytic anaemia among glucose-6-phosphate dehydrogenase (G6PD) deficient individuals. The distribution of G6PD deficiency in Brazzaville, Republic of Congo and the association of G6PD deficiency with haemoglobin levels and blood cell counts were investigated. METHODS:A total of 212 febrile children were recruited for this study. Plasmodium falciparum diagnosis was conducted by microscopy and nested PCR. Sanger sequencing was used to assess G6PD deficiency by detecting 202G>A (rs1050828) and 376A>G (rs1050829) single nucleotide polymorphisms. RESULTS:Two hundred and twelve children were successfully genotyped for G6PD variants. Overall, 13% (27/212) of the children were G6PD deficient and 25% (25/100) females were heterozygous (11 BA- and 14 A+A-). The remaining 160 children had a normal G6PD genotype. The mean red blood and mean platelet counts were significantly lower in hemizygous male (G6PD A-) participants than in normal male (G6PD A+ or B) participants (p?<?0.05). CONCLUSION:This study gives an update on G6PD deficiency among Congolese children. Understanding the distribution of G6PD deficiency in other geographical regions is recommended before primaquine is adopted in the malaria control programme.
| S-EPMC6396490 | biostudies-literature
Project description:Early 2019, a chikungunya virus (CHIKV) outbreak hit the Democratic Republic of the Congo (DRC). Though seldomly deadly, this mosquito-borne disease presents as an acute febrile (poly)arthralgia often followed by long-term sequelae. Although Aedes aegypti is the primary vector, an amino acid substitution in the viral envelope gene E1 (A226V) is causing concern as it results in increased transmission by Aedes albopictus, a mosquito with a much wider geographical distribution. Between January and March 2019, we collected human and mosquito samples in Kinshasa and Kongo Central province (Kasangulu and Matadi). Of the patients that were tested within 7 days of symptom onset, 49.7% (87/175) were RT-qPCR positive, while in the mosquito samples CHIKV was found in 1/2 pools in Kinshasa, 5/6 pools in Kasangulu, and 8/26 pools in Matadi. Phylogenetic analysis on whole-genome sequences showed that the circulating strain formed a monophyletic group within the ECSA2 lineage and harboured the A226V mutation. Our sequences did not cluster with sequences from previously reported outbreaks in the DRC nor with other known A226V-containing ECSA2 strains. This indicates a scenario of convergent evolution where A226V was acquired independently in response to a similar selection pressure for transmission by Ae. albopictus. This is in line with our entomological data where we detected Ae. albopictus more frequently than Ae. aegypti in two out of three affected areas. In conclusion, our findings suggest that CHIKV is adapting to the increased presence of Aedes albopictus in DRC.
| S-EPMC8284967 | biostudies-literature
Project description:BackgroundAlthough Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these require more attention in Africa. Information on the epidemiological situation of non-P. falciparum species infections is scarce in many countries, including in the Democratic Republic of the Congo (hereafter Republic of the Congo) where malaria is highly endemic. The aim of this study was to determine the prevalence and distribution of non-P. falciparum species infections in the region south of Brazzaville.MethodsA cross-sectional survey was conducted in volunteers living in rural and urban settings during the dry and rainy seasons in 2021. Socio-demographic and clinical parameters were recorded. Plasmodium infection in blood samples was detected by microscopic analysis and nested PCR (sub-microscopic analysis).ResultsOf the 773 participants enrolled in the study, 93.7% were from the rural area, of whom 97% were afebrile. The prevalence of microscopic and sub-microscopic Plasmodium spp. infection was 31.2% and 63.7%, respectively. Microscopic Plasmodium malariae infection was found in 1.3% of participants, while sub-microscopic studies detected a prevalence of 14.9% for P. malariae and 5.3% for Plasmodium ovale. The rate of co-infection of P. malariae or P. ovale with P. falciparum was 8.3% and 2.6%, respectively. Higher rates of sub-microscopic infection were reported for the urban area without seasonal fluctuation. In contrast, non-P. falciparum species infection was more pronounced in the rural area, with the associated risk of the prevalence of sub-microscopic P. malariae infection increasing during the dry season.ConclusionThere is a need to include non-P. falciparum species in malaria control programs, surveillance measures and eradication strategies in the Republic of the Congo.
| S-EPMC9200623 | biostudies-literature
Project description: Not available
| S-EPMC4313651 | biostudies-literature
Project description:Tuberculosis is a leading cause of illness and death in Congo. No data are available about the population structure and transmission dynamics of the Mycobacterium tuberculosis complex strains prevalent in this central Africa country. On the basis of single-nucleotide polymorphisms detected by whole-genome sequencing, we phylogenetically characterized 74 MTBC isolates from Brazzaville, the capital of Congo. The diversity of the study population was high; most strains belonged to the Euro-American lineage, which split into Latin American Mediterranean, Uganda I, Uganda II, Haarlem, X type, and a new dominant sublineage named Congo type (n = 26). Thirty strains were grouped in 5 clusters (each within 12 single-nucleotide polymorphisms), from which 23 belonged to the Congo type. High cluster rates and low genomic diversity indicate recent emergence and transmission of the Congo type, a new Euro-American sublineage of MTBC.
| S-EPMC5382753 | biostudies-literature
Project description:Polioviruses isolated from 70 acute flaccid paralysis patients from the Democratic Republic of Congo (DRC) during 2004-2011 were characterized and found to be vaccine-derived type 2 polioviruses (VDPV2s). Partial genomic sequencing of the isolates revealed nucleotide sequence divergence of up to 3.5% in the viral protein 1 capsid region of the viral genome relative to the Sabin vaccine strain. Genetic analysis identified at least 7 circulating lineages localized to specific geographic regions. Multiple independent events of VDPV2 emergence occurred throughout DRC during this 7-year period. During 2010-2011, VDPV2 circulation in eastern DRC occurred in an area distinct from that of wild poliovirus circulation, whereas VDPV2 circulation in the southwestern part of DRC (in Kasai Occidental) occurred within the larger region of wild poliovirus circulation.
| S-EPMC3810735 | biostudies-literature
Project description:The African continent is currently experiencing rapid population growth, with rising urbanization increasing the percentage of the population living in large towns and cities. We studied the impact of the degree of urbanization on the population genetics of Plasmodium falciparum in urban and peri-urban areas in and around the city of Brazzaville, Republic of Congo. This field setting, which incorporates local health centers situated in areas of varying urbanization, is of interest as it allows the characterization of malaria parasites from areas where the human, parasite, and mosquito populations are shared, but where differences in the degree of urbanization (leading to dramatic differences in transmission intensity) cause the pattern of malaria transmission to differ greatly. We have investigated how these differences in transmission intensity affect parasite genetic diversity, including the amount of genetic polymorphism in each area, the degree of linkage disequilibrium within the populations, and the prevalence and frequency of drug resistance markers. To determine parasite population structure, heterozygosity and linkage disequilibrium, we typed eight microsatellite markers and performed haplotype analysis of the msp1 gene by PCR. Mutations known to be associated with resistance to the antimalarial drugs chloroquine and pyrimethamine were determined by sequencing the relevant portions of the crt and dhfr genes, respectively. We found that parasite genetic diversity was comparable between the two sites, with high levels of polymorphism being maintained in both areas despite dramatic differences in transmission intensity. Crucially, we found that the frequencies of genetic markers of drug resistance against pyrimethamine and chloroquine differed significantly between the sites, indicative of differing selection pressures in the two areas.
| S-EPMC3156131 | biostudies-literature
Project description:BACKGROUND:In the Republic of Congo, hot temperature and seasons distortions observed may impact the development of malaria parasites. We investigate the variation of malaria cases, parasite density and the multiplicity of Plasmodium falciparum infection throughout the year in Brazzaville. METHODS:From May 2015 to May 2016, suspected patients with uncomplicated malaria were enrolled at the Hôpital de Mfilou, CSI « Maman Mboualé», and the Laboratoire National de Santé Publique. For each patient, thick blood was examined and parasite density was calculated. After DNA isolation, MSP1 and MSP2 genes were genotyped. RESULTS:A total of 416, 259 and 131 patients with suspected malaria were enrolled at the CSI «Maman Mboualé», Hôpital de Mfilou and the Laboratoire National de Santé Publique respectively. Proportion of malaria cases and geometric mean parasite density were higher at the CSI «Maman Mboualé» compared to over sites (P-value <0.001). However the multiplicity of infection was higher at the Hôpital de Mfilou (P-value <0.001). At the Laboratoire National de Santé Publique, malaria cases and multiplicity of infection were not influenced by different seasons. However, variation of the mean parasite density was statistically significant (P-value <0.01). Higher proportions of malaria cases were found at the end of main rainy season either the beginning of the main dry season at the Hôpital de Mfilou and the CSI «Maman Mboualé»; while, lowest proportions were observed in September and January and in September and March respectively. Higher mean parasite densities were found at the end of rainy seasons with persistence at the beginning of dry seasons. The lowest mean parasite densities were found during dry seasons, with persistence at the beginning of rainy seasons. Fluctuation of the multiplicity of infection throughout the year was observed without significance between seasons. CONCLUSION:The current study suggests that malaria transmission is still variable between the north and south parts of Brazzaville. Seasonal fluctuations of malaria cases and mean parasite densities were observed with some extension to different seasons. Thus, both meteorological and entomological studies are needed to update the season's periods as well as malaria transmission intensity in Brazzaville.
| S-EPMC7057455 | biostudies-literature
Project description:During 2011-2013, a nationwide outbreak of chikungunya virus infection occurred in the Philippines. The Asian genotype was identified as the predominant genotype; sporadic cases of the East/Central/South African genotype were detected in Mindanao. Further monitoring is needed to define the transmission pattern of this virus in the Philippines.
| S-EPMC4861512 | biostudies-literature