Prevalence of Dengue virus among healthy blood donors in Mombasa County, Kenya

Introduction: Dengue fever (DF) is a viral infection caused by a flavivirus called Dengue virus. The virus has four known serotypes (named DENV 1-4) that circulate between humans and Aedes mosquitoes throughout the tropical region of the world. The virus is transmitted primarily by the bite of an infected Aedes aegypti or, to a lesser extent, Aedes albopictus. Current evidence from published case studies shows that blood transfusions can transmit Dengue infection in hyperendemic regions in the tropics. It is important to note that 75% of people infected with DENV show no symptoms. Therefore, an infected individual could be accepted as a blood donor and spread the disease. In Kenya, frequent Dengue outbreaks have been reported in the coastal counties of Mombasa, Kilifi, and Kwale in recent years. This study aimed to determine the seroprevalence of Dengue virus among blood donors in a selected endemic region of the Republic of Kenya. Methods: the researchers used a cross-sectional research design to collect data from blood donors in two selected counties in Kenya in 2023. A self-directed questionnaire was used to collect sociodemographic data and risk factors associated with Dengue fever from consenting participants. Additionally, a 5-ml sample of blood was collected and serologically analyzed for anti-Dengue IgG, IgM, and NS1 using a commercial rapid Dengue testing duo kit (Bioline™ DENGUE DUO (Dengue NS1 Ag + IgG/IgM)). The data were summarized and presented using tables and bar graphs. Results: at the end of the study, the researchers recruited 103 participants from the selected study sites in Mombasa County. Most of the research participants were men between 20 and 30 years of age. The prevalence of Dengue virus seromarkers was 24%, 11%, and 2% for IgG, IgM, and NS1, respectively. These were detected among young adult donors between the ages of 20 and 30 years. Statistically, there was an association between anti-Dengue IgM positivity with a history of admission (p-value = 0.0015), fever in the last 6 months (p-value = 0.0015) and a history of living with a DF infected person in the last 6 months (p-value = 0.011). Similarly, there was a statistically significant association between anti-Dengue IgG positivity and length of stay in Mombasa County (p-value = 0.005), history of admission in the last 6 months (p-value =0.003), history of fever in the last 6 months (p-value = 0.004) and lived with a victim of Dengue fever in the last 6 months (p-value = 0.02) in a 95% confidence interval. Conclusion: according to the study findings, a sizeable proportion of eligible blood donors in Mombasa are Dengue virus-infected, some possibly carrying the virus without showing symptoms. The study identified IgG and IgM as the most prevalent serological markers. To protect blood recipients in Mombasa County and other Dengue-endemic counties such as Kilifi, Kwale, Lamu, and Taita Taveta, it is recommended that blood donors in these regions undergo regular screening, particularly during Dengue outbreaks

Dengue virus and blood safety: a mini-review of research publications

The growing demand for donated whole blood and blood products to save lives has both health benefits and health risks for blood recipients at the same time. Dengue virus, a re-emerging viral disease poses a threat to blood safety, and it has spread to over 128 countries in the world. Several studies have documented transfusion-transmitted (TT) dengue, with the first cases being reported in China in 2002 and Singapore in 2008. To understand the magnitude and broader picture of the dengue virus and blood safety, we conducted a mini-review of published literature from the Scopus database. The review focused on the number of publications related to the dengue virus among blood donors. Using keywords ‘Dengue virus’ AND ‘Blood safety’, ‘ Dengue virus’ AND ‘Blood donors’ and ‘Emerging infectious diseases’ AND “Blood safety” were used to extract data from the Scopus database which was downloaded as a CSV Excel file covering a period 2004 to 2021. This was followed by a data-cleaning exercise and a descriptive analysis to generate the frequency of the number of publications. Most studies, as can be seen in the review, were concentrated in tropical regions of the world. Globally, South America and the Asian regions had the largest number of publications; while at the country level, Brazil and India had the highest number. More research output was witnessed during the years 2014 and 2018. The regions that experienced more frequent outbreaks of the disease, with the exception Africa, published most of the research work. Therefore, much more research work is needed to protect the safety of blood donors in Africa

Dengue Virus Surveillance and Blood Safety: A One Health Perspective

The provision of blood products to save a life is a noble undertaking for any organization tasked with the duty. In addition to saving millions of lives, blood products pose health risks associated with adverse events. Much has been done to mitigate these challenges, but emerging new infectious diseases pose a public health challenge to both the safety of blood and its availability. The dengue virus an arbovirus is one such virus that is endemic in tropical and subtropical countries. The data emerging from the published papers show that dengue could be a major threat to blood safety and availability in the future. To address these threats, a collaborative approach through one health system is the only avenue to provide a last solution. One health has been implemented as a strategy to mitigate zoonotic diseases and its results are very impressive. This piece of work is a fraction of our larger project that aims to address threats to the dengue virus and blood safety in Kenya and the rest of Africa. In conclusion, adopting one health in the fight against the dengue virus in blood safety will be the best approach to ensure a safer supply of blood products

Trypanosoma

African Animal Trypanosomiasis (AAT) transmitted cyclically by tsetse fly (Glossina spp.) is a major obstacle to livestock production in the tropical parts of Africa. The objective of this study was to determine the infection rates of trypanosomes in Glossina species in Mtito Andei Division, Makueni County, Kenya. Tsetse fly species, G. longipennis and G. pallidipes, were trapped and DNA was isolated from their dissected internal organs (proboscis, salivary glands, and midguts). The DNA was then subjected to a nested PCR assay using internal transcribed spacer primers and individual trypanosome species were identified following agarose gel electrophoresis. Out of the 117 flies trapped in the area 39 (33.3%) were teneral while 78 (67%) were nonteneral. G. pallidipes constituted the largest percentage of 58% while G. longipennis were 42%. The overall trypanosomes infection rate in all nonteneral Glossina spp. was 11.53% with G. longipennis recording the highest infection rate of 23.08% while G. pallidipes had an infection rate of 5.77%. T. vivax was the most infectious (10.26%) compared to T. congolense (1.28%). Mean apparent densities were strongly positively correlated with infection rates (r=0.95) confirming the importance of this parameter as an indicator of AAT transmission risk

Correlates of contraceptive use among HIV discordant couples in Kenya

Despite risks of HIV transmission to infants born of the HIV positive women, contraceptive use is uncommon among women in HIV discordant partnerships. The aim of this study was to determine the factors associated with contraceptive use in a clinical trial cohort of HIV serodiscordant couples based in Thika and Eldoret, Kenya. Data were analyzed from 481 HIV discordant couples enrolled in the Partners in Prevention HSV/HIV Transmission Study at the Thika and Eldoret sites. The primary study outcome was self-reported use of contraception other than condoms. Using a marginal longitudinal logistic model based on generalized estimating equations (GEE) approach we assessed the association of various demographic and behavioral factors with contraceptive use. At baseline the prevalence of non barrier contraceptive use among HIV positive and negative women was 24.3% and 25.7%, respectively. At month 12 of follow-up, the prevalence of contraceptive use was 44.4% among the HIV positive and 26% among the HIV negative women while at month 24, the prevalence of contraceptive use was 38.6% among the HIV positive and 18.2% among the HIV negative women. HIV positive women were more likely to report using contraception than HIV negative women (odds ratio (OR) 1.61 95% confidence interval (CI) 1.04-2.47). Additionally, being married (OR 2.4, 95% CI 1.2-5.0), attending Thika site clinic (OR 6.1, 95% CI 4.2-9.0), and having two or more children (OR 1.9, 95% CI 1.3-2.8) were significantly associated with use of non barrier contraceptives. Future programs should focus on interventions to increase contraceptive use among HIV serodiscordant couples, with a special emphasis on HIV negative women, unmarried women and women with few children

Mutations in the “a” Determinant Region of Hepatitis B Virus Genotype A among Voluntary Kenyan Blood Donors

Background: Occurrence of mutations within the major antigenic alpha determinant region of hepatitis B surface antigen (HBsAg can alter HBV antigenicity resulting in   failures in diagnosis, vaccine and hepatitis B immunoglobulin therapy. Objective: This study aimed at detection of mutations in the “a” determinant region of HBV surface antigen among voluntary blood donors in Kenya. Design: A cross sectional study involving serology and molecular techniques Settings: This study involved analysis of samples from blood transfusion centers Subjects: A total of 301 blood samples from donor blood were collected for the study. Methods: Sero-status for HBsAg was determined using Enzyme-Linked Immunosorbent Assay (ELISA). A fragment of the S gene including the "a" determinant was amplified by PCR from the HBsAg positive samples and sequenced for mutation analysis. Mutations and phylogenetic analyses were performed using Mega 6 software, Bioedit software and GENETYX® software version 9.1.0. Results: Out of the 301 samples tested 69/301 (22.9%) were Polymerase Chain Reaction (PCR) positive including 2/69(2.9%) were sero-negative for HBsAg. All isolates were genotype A, sub-genotype A1. A total of 29 mutations were observed of which 37.9% were located within the “a” determinant. Mutations T143M and K122R were the most frequent in this study. Escape mutations associated with diagnostic failure, vaccine and immunoglobulin therapy escape were also identified. Conclusions: These findings are important for policies related to vaccine implementation and therapeutic and diagnostic guidelines. Keywords: Escape mutants, genotype, hepatitis B virus, antigenic determinant, surface antigen

The effect of participant nonresponse on HIV prevalence estimates in a population-based survey in two informal settlements in Nairobi city

BACKGROUND: Participant nonresponse in an HIV serosurvey can affect estimates of HIV prevalence. Nonresponse can arise from a participant's refusal to provide a blood sample or the failure to trace a sampled individual. In a serosurvey conducted by the African Population and Health Research Center and Kenya Medical Research Centre in the slums of Nairobi, 43% of sampled individuals did not provide a blood sample. This paper describes selective participation in the serosurvey and estimates bias in HIV prevalence figures. METHODS: The paper uses data derived from an HIV serosurvey nested in an on-going demographic surveillance system. Nonresponse was assessed using logistic regression and multiple imputation methods to impute missing data for HIV status using a set of common variables available for all sampled participants. RESULTS: Age, residence, high mobility, wealth, and ethnicity were independent predictors of a sampled individual not being contacted. Individuals aged 30-34 years, females, individuals from the Kikuyu and Kamba ethnicity, married participants, and residents of Viwandani were all less likely to accept HIV testing when contacted. Although men were less likely to be contacted, those found were more willing to be tested compared to females. The overall observed HIV prevalence was overestimated by 2%. The observed prevalence for male participants was underestimated by about 1% and that for females was overestimated by 3%. These differences were small and did not affect the overall estimate substantially as the observed estimates fell within the confidence limits of the corrected prevalence estimate. CONCLUSIONS: Nonresponse in the HIV serosurvey in the two informal settlements was high, however, the effect on overall prevalence estimate was minimal

Mutations in the “a” Determinant Region of Hepatitis B Virus Genotype A among Voluntary Kenyan Blood Donors

Occurrence of mutations within the major antigenic alpha determinant region of hepatitis B surface antigen (HBsAg can alter HBV antigenicity resulting in   failures in diagnosis, vaccine and hepatitis B immunoglobulin therapy. This study aimed at detection of mutations in the “a” determinant region of HBV surface antigen among voluntary blood donors in Kenya. This was a cross sectional study involving serology and molecular techniques. This study involved analysis of samples from blood transfusion centers. A total of 301 blood samples from donor blood were collected for the study.  Sero-status for HBsAg was determined using Enzyme-Linked Immunosorbent Assay (ELISA). A fragment of the S gene including the "a" determinant was amplified by PCR from the HBsAg positive samples and sequenced for mutation analysis. Mutations and phylogenetic analyses were performed using Mega 6 software, Bioedit software and GENETYX® software version 9.1.0. Out of the 301 samples tested 69/301 (22.9%) were Polymerase Chain Reaction (PCR) positive including 2/69(2.9%) were sero-negative for HBsAg. All isolates were genotype A, sub-genotype A1. A total of 29 mutations were observed of which 37.9% were located within the “a” determinant. Mutations T143M and K122R were the most frequent in this study. Escape mutations associated with diagnostic failure, vaccine and immunoglobulin therapy escape were also identified. These findings are important for policies related to vaccine implementation and therapeutic and diagnostic guidelines. Keywords: Escape mutants, genotype, hepatitis B virus, antigenic determinant, surface antige

Clinical epidemiology of COVID-19 among hospitalized children in rural western Kenya

The epidemiology of pediatric COVID-19 in sub-Saharan Africa and the role of fecal-oral transmission in SARS-CoV-2 are poorly understood. Among children and adolescents in Kenya, we identify correlates of COVID-19 infection, document the clinical outcomes of infection, and evaluate the prevalence and viability of SARS-CoV-2 in stool. We recruited a prospective cohort of hospitalized children aged two months to 15 years in western Kenya between March 1 and June 30 2021. Children with SARS-CoV-2 were followed monthly for 180-days after hospital discharge. Bivariable logistic regression analysis was used to identify the clinical and sociodemographics correlates of SARS-CoV-2 infection. We also calculated the prevalence of SARS-CoV-2 detection in stool of confirmed cases. Of 355 systematically tested children, 55 (15.5%) were positive and were included in the cohort. The commonest clinical features among COVID-19 cases were fever (42/55, 76%), cough (19/55, 35%), nausea and vomiting (19/55, 35%), and lethargy (19/55, 35%). There were no statistically significant difference in baseline sociodemographic and clinical characteristics between SARS-CoV-2 positive and negative participants. Among positive participants, 8/55 (14.5%, 95%CI: 5.3%-23.9%) died; seven during the inpatient period. Forty-nine children with COVID-19 had stool samples or rectal swabs available at baseline, 9 (17%) had PCR-positive stool or rectal swabs, but none had SARS-CoV-2 detected by culture. Syndromic identification of COVID-19 is particularly challenging among children as the presenting symptoms and signs mirror other common pediatric diseases. Mortality among children hospitalized with COVID-19 was high in this cohort but was comparable to mortality seen with other common illnesses in this setting. Among this small set of children with COVID-19 we detected SARS-CoV-2 DNA, but were not able to culture viable SARs-CoV-2 virus, in stool. This suggests that fecal transmission may not be a substantial risk in children recently diagnosed and hospitalized with COVID-19 infection