Browsing by Author "Nyamache, Anthony K."

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    Hepatitis B Virus Sero-profiles and Genotypes in HIV-1 Infected and Uninfected Injection and Non-injection Drug Users from Coastal Kenya
    (BioMed Central, 2015) Kilongosi, Mark W.; Budambula, Valentine; Lihana, Raphael; Musumba, Francis O.; Nyamache, Anthony K.; Budambula, Nancy L. M.; Ahmed, Aabid A.; Ouma, Collins; Were, Tom
    Background: Information about HBV sero-markers, infection stages and genotypes in HIV-1 infected and uninfected injection and non-injection drug users (IDUs) in Kenya remains elusive. Methods: A cross-sectional study examining HBV sero-marker, infection stages and genotypes was conducted among HIV-1 infected and uninfected, respectively, IDUs (n = 157 and n = 214) and non-IDUs (n = 139 and n = 48), and HIV-1 uninfected non-drug using controls (n = 194) from coastal, Kenya. HBV sero-marker and infection stages were based on HBV 5-panel rapid test plasma sero-reactivity. DNA was extracted from acute and chronic plasma samples and genotypes established by nested-PCR and direct sequencing. Results: HBsAg positivity was higher in HIV-1 infected IDUs (9.6 %) relative to HIV-1 uninfected IDUs (2.3 %), HIV-1 infected non-IDUs (3.6 %), HIV-1 uninfected non-IDUs (0.0 %) and non-drug users (2.6 %; P = 0.002). Contrastingly, HBsAb positivity was higher in HIV-1 uninfected IDUs (14.6 %) and non-IDUs (16.8) in comparison to HIV-1 infected IDUs (8.3 %), and non-IDUs (8.6 %), and non-drug users (8.2 %; P = 0.023). HBcAb positivity was higher in HIV-1 infected IDUs (10.2 %) compared to HIV-1 uninfected IDUs (3.3 %), HIV-1 infected non-IDUs (6.5 %), HIV-1 uninfected non-IDUs (2.1 %) and non-drug users (4.6 %; P = 0.038). Acute (5.7 %, 1.4 %, 0.0 %, 0.0 % and 1.5 %) and chronic (5.1 %, 0.9 %, 3.6 %, 0.0 % and 1.5 %) stages were higher in HIV-1 infected IDUs, compared to HIV-1 uninfected IDUs, HIV-1 infected and uninfected non-IDUs and non-drug users, respectively. However, vaccine type response stage was higher in HIV-1 uninfected IDUs (15.4 %) relative to HIV-1 infected IDUs (6.4 %), and HIV-1 infected (6.5 %), and uninfected (10.4 %) non-IDUs, and non-drug users (5.7 %; P = 0.003). Higher resolved infection rates were also recorded in HIV-1 uninfected IDUs (11.2 %) compared to HIV-1 infected IDUs (8.3 %), and HIV-1 infected (7.2 %), uninfected (6.3 %) non-IDUs, and non-drug users (6.7 %; P = 0.479), respectively. Only A1 genotype showing minimal diversity was detected among the study participants. Conclusion: HBV sero-markers and infection staging are valuable in diagnosis and genotyping of HBV infections. Among IDUs, higher HBsAg and HBcAb positivity in HIV-1 infected and higher HBsAb positivity in HIV-1 negative IDUs suggests frequent exposure. Additionally, HBV genotype A is the dominant circulating genotype in both high and low risk populations of Kenya.
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    Serotype Diversity of Foot and Mouth Disease Virus and Molecular Characterization of Serotype O Strains from 2019 and 2020 Outbreaks in Kenya
    (Benha Veterinary Medical Journal, 2024) Josiah, Judith M.; Nyamache, Anthony K.; Woldemariyam, Fanos T.; Kariuki, Christopher K.; Paeshuyse, Jan; Kamau, Joseph
    Foot and mouth disease (FMD) is a viral infection affecting ruminants and leads to great economic losses. Control and prevention have been a challenge despite the availability of vaccines. The causative agent exists in seven serotypes and is endemic in Kenya, with serotypes O, A, SAT (South African Territory) 1, and SAT 2 and having circulated in the recent past. This study was aimed at determining the current serotype diversity and serotype O variants during the study period. A cross-sectional study was conducted and a total of 267 epithelial samples were collected from animals during the disease outbreaks of 2019 and 2020. Antigen detection was performed using ELISA (Enzyme-Linked Immunosorbed Assay). The negative samples were inoculated on LFBK(Line of Fetal Bovine Kidney) monolayer cells followed by a repeat ELISA for CPE(Cytopathic Effect) positive samples. The partial VP1 gene for serotype O samples was amplified and directly sequenced. The generated sequences were analyzed and compared with the vaccine strain. The prevalence of FMDV was 65.9% (176/267) and serotypes SAT 1, O, SAT 2, and A in the order of decreasing prevalence were circulating. Serotype O viruses analyzed belonged to the EA 2 against the EA 1 vaccine strain in use. For better control of the disease, this study recommends close monitoring of the circulating serotypes and topotypes, and, regular vaccine matching to ensure vaccine effectiveness.