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Background. Q fever is the one of the best-studied zoonoses, which is widespread throughout almost the entire territory of Africa, excluding the territory of the Sahara. However, the current data on the incidence of coxiellosis and the circulation of Coxiella burnetii on this continent are limited and vary according different sources. In 1980–1990, the Soviet-Guinean Research Virology and Microbiology Laboratory conducted studies to estimate the distribution of the Q fever pathogen, assess the herd immunity in humans and identify specific antibodies in the sera of livestock. However, in subsequent years, the research was suspended. The aim of this study is to obtain up-to-date data on the distribution of C. burnetii in all landscape and geographical zones of the Republic of Guinea. Materials and methods. The study was carried out in the laboratory of the Russian-Guinean Center for Epidemiology and Prevention of Infectious Diseases (Kindia, Republic of Guinea). The study involved 332 sera of febrile patients and 3156 sera from practically healthy volunteers, 1074 blood samples of livestock, 1648 suspensions of ticks, 319 specimens of small mammals and 298 of bats. The study was carried out using ELISA and PCR methods, selected samples were subjected to in-depth genetic analysis. Results and discussion. The study of the distribution of C. burnetii on the territory of all landscape-geographical zones of the Republic of Guinea was carried out. For the first time, an officially registered case of human Q fever case has been identified. The role of livestock, small mammals and bats in the circulation of the pathogen has been established. It has been shown that the main vectors in Guinea are ixodid ticks of the Amblyomma variegatum, Hyalomma truncatum and Rhipicephalus decoloratus species. Employing molecular methods, C. burnetii strains carrying the QpH1 plasmid, capable of causing diseases in humans and animals were identified. For the first time, the complete nucleotide sequence of 16S rRNA of the Q fever pathogen (OQ152497–OQ152500) identified on the territory of Guinea was determined and registered in the GenBank database. Conclusion. Taking into account the high epidemiological significance of Q fever, the study of the specifics of C. burnetii circulation in Guinea remains an urgent task. Regular monitoring and assessment of risk factors for diseases caused by coxiella are necessary for the development of an algorithm for laboratory diagnosis and recommendations for clinicians.

Introduction. The vertical route of hepatitis B virus (HBV) transmission is a significant problem in African countries, which is characterized by late diagnosis of the disease and high mortality. The high prevalence of hepatocellular carcinoma (HCC) in Africa may be due to variability in the HBV preCore/Core region, mutations in which contribute to disease progression. Molecular genetic characterization of strains circulating among pregnant women may reflect the overall mutational profile of the pathogen in the population. The objective of this study was to analyze the variability of the HBV preCore/Core region circulating among pregnant women in the Republic of Guinea. Materials and methods. The study material included 480 plasma samples obtained from HBV-positive pregnant women from the Republic of Guinea. For all samples, the nucleotide sequences of the preCore/Core region of the HBV genome were sequenced and analyzed. Results. Amino acid variability in the preCore region was determined in 211 (43.96%), and in the Core region in 473 (98.54%) patients. 12 polymorphic sites of the preCore region were identified in which amino acid substitutions occurred, including 8, 2 and 5 positions identified for genotypes E, A and D, respectively. In the Core region, 67 substitution positions were identified, including 46 in samples of genotype E, 23 in HBV genotype A and 26 in genotype D. It was shown that the distribution of substitutions in the preCore and Core regions in HBV genotypes E, A and D differs significantly with a predominance in mutations among HBV genotype E — p 0.0001. Individual characteristic mutations have been identified for each genotype. The most common clinically significant mutations in the preCore/Core region in the study group were identified, including pc-H5D (27,08%), pc-W28* (35,21%), c-E64D (33,54%), c-L116I/V/G (91,46 %), c-T146N (73,13%). The double mutation A1762T/G1764A in the basal core promoter was shown in 74 samples of HBV genotype E, which accounted for 15.42% of the total group and 16.59% of patients with HBV genotype E. Conclusion. The frequency of clinically significant preCore/Core mutations among pregnant women in the Republic of Guinea was determined. The data obtained reflect their prevalence in the general population and can be used to predict the progression of chronic HBV among the region's population.

Introduction. Ixodes ticks are vectors for pathogens of many infectious diseases. Recently, during the study of Rhipicephalus geigyi ticks collected from livestock in the Republic of Guinea, a new multicomponent flavi-like RNA virus, called Kindia tick virus (KITV), was discovered with an unusual mechanism for the implementation of genetic information. The aim of the work is to detect and study the genetic diversity of KITV in ixodes ticks collected in the territory of the Kindia province of the Republic of Guinea. Material and methods. In 2021, 324 specimens of ticks of the species Amblyomma variegatum, Rh. geigyi, Rh. annulatus, Rh. decoloratus, Rh. senegalensis were collected from cattle. The detection of viral RNA was carried out in individual samples of ticks by RT-PCR, followed by the determination of the nucleotide sequence and phylogenetic analysis. Results and discussion. KITV detection rates in ticks of the species Rh. geigyi was 12.2%, Rh. annulatus 4.4%, Rh. decoloratus 3.3%. However, the KITV genetic material has not been identified in Am. variegatum ticks, which are one of the dominant species in West Africa. For all virus isolates, a partial nucleotide sequences of each of the four viral segments (GenBank, OK345271OK345306) were determined. The phylogenetic analysis showed a high level of identity (98.599.8%) for each of the four segments of the viral genome with those previously found in the Republic of Guinea. The obtained KITV isolates are most genetically close to Mogiana tick virus, which was previously detected in South America in Rh. microplus ticks and significantly differed from other multicomponent viruses circulating in Europe and Asia, including the Russian Federation. Conclusion. KITV genetic material was found in three species of ixodid ticks collected from livestock in a number of prefectures of the Republic of Guinea. The infection rate in ticks was 3.312.2%. The continuation of research in this direction remains relevant.

The Zika virus (ZIKV) is a widespread mosquito-borne pathogen. Phylogenetically, two lineages of ZIKV are distinguished: African and Asian–American. The latter became the cause of the 2015–2016 pandemic, with severe consequences for newborns. In West African countries, the African lineage was found, but there is evidence of the emergence of the Asian–American lineage in Cape Verde and Angola. This highlights the need to not only monitor ZIKV but also sequence the isolates. In this article, we present a case report of Zika fever in a pregnant woman from Guinea identified in 2018. Viral RNA was detected through qRT-PCR in a serum sample. In addition, the seroconversion of anti-Zika IgM and IgG antibodies was detected in repeated blood samples. Subsequently, the virus was isolated from the C6/36 cell line. The detected ZIKV belonged to the African lineage, the Nigerian sublineage. The strains with the closest sequences were isolated from mosquitoes in Senegal in 2011 and 2015. In addition, we conducted the serological screening of 116 blood samples collected from patients presenting to the hospital of Faranah with fevers during the period 2018–2021. As a result, it was found that IgM-positive patients were identified each year and that the seroprevalence varied between 5.6% and 17.1%.