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

Infection with soil-transmitted helminths and their impact on coinfections

The most important soil-transmitted helminths (STHs) affecting humans are roundworms, whipworms, and hookworms, with a large proportion of the world’s population infected with one or more of these intestinal parasites. On top of that, concurrent infections with several viruses, bacteria, protozoa, and other helminths such as trematodes are common in STH-endemic areas. STHs are potent immunomodulators, but knowledge about the effects of STH infection on the direction and extent of coinfections with other pathogens and vice versa is incomplete. By focusing on Kenya, a country where STH infections in humans are widespread, we provide an exemplary overview of the current prevalence of STH and co-occurring infections (e.g. with Human Immunodeficiency Virus, Plasmodium falciparum, Giardia duodenalis and Schistosoma mansoni). Using human data and complemented by experimental studies, we outline the immunomechanistic interactions of coinfections in both acutely STH transmigrated and chronically infected tissues, also highlighting their systemic nature. Depending on the coinfecting pathogen and immunological readout, STH infection may restrain, support, or even override the immune response to another pathogen. Furthermore, the timing of the particular infection and host susceptibility are decisive for the immunopathological consequences. Some examples demonstrated positive outcomes of STH coinfections, where the systemic effects of these helminths mitigate the damage caused by other pathogens. Nevertheless, the data available to date are rather unbalanced, as only a few studies have considered the effects of coinfection on the worm’s life cycle and associated host immunity. These interactions are complex and depend largely on the context and biology of the coinfection, which can act in either direction, both to the benefit and detriment of the infected host

Epidemiology of multi-drug resistant Tuberculosis in the western region of Kenya

Multidrug-resistant tuberculosis (TB) (MDR-TB), or TB that is simultaneously resistant to both isoniazid (INH) and rifampicin (RIF), is a barrier to successful TB control and treatment. Stratified data on MDR-TB, particularly in the high-burden western Kenya region, remain unknown. This data is important to monitor the efficacy of TB control and treatment efforts. Herein, we determined the molecular epidemiology of drug-resistant TB and associated risk factors in western Kenya. This was a non-experimental, population-based, cross-sectional study conducted between January and August 2018. Morning sputum samples of individuals suspected of pulmonary TB were collected, processed, and screened for Mycobacterium tuberculosis (Mtb) and drug resistance using line probe assay (LPA) and Mycobacterium growth indicator tubes (MGIT) culture. MGIT-positive samples were cultured on brain heart infusion (BHII) agar media, and the presence of Mtb was validated using Immunochromatographic assay (ICA). Drug sensitivity was performed on MGIT and ICA-positive but BHI-negative samples. Statistical significance was set at P < 0.05. Of the 622 Mtb isolates, 536 (86.2%) were susceptible to RIF and INH. The rest, 86 (13.83%), were resistant to either drugs or both. A two-sample proportional equality test revealed that the MDR-TB prevalence in western Kenya (5%) did not vary significantly from the global MDR-TB estimate (3.9%) (P = 0.196). Men comprised the majority of susceptible and resistant TB (75.9% and 77.4%%, respectively). Also, compared with healthy individuals, the prevalence of HIV was significantly higher in MDR-TB patients (35.9% vs 5.6%). Finally, TB prevalence was highest in individuals aged 25–44 years, who accounted for 58.4% of the total TB cases. Evidently, the prevalence of MDRTB in western Kenya is high. Particular attention should be paid to men, young adults, and those with HIV, who bear the greatest burden of resistant TB. Overall, there is a need to refine TB control and treatment programs in the region to yield better outcomes

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

Development of a rapid and highly sensitive nucleic acid-based diagnostic test for schistosomes, leveraging on identical multi-repeat sequences

IntroductionSchistosomiasis (Bilharzia), a neglected tropical disease caused by Schistosoma parasites, afflicts over 240 million people globally, disproportionately impacting Sub-Saharan Africa. Current diagnostic tests, despite their utility, suffer from limitations like low sensitivity. Polymerase chain reaction (PCR) and quantitative real-time PCR (qPCR) remain the most common and sensitive nucleic acid amplification tests. Still, the sensitivity of nucleic acid amplification tests is significantly affected by the copy number of amplification targets, resulting in underestimation of true Schistosoma infections, especially in low transmission settings. Additionally, lengthy qPCR run times pose challenges when dealing with large sample volumes and limited resources. In this study, the identical multi-repeat sequences (IMRS) were used as a novel approach to enhance the sensitivity of nucleic acid-based Bilharzia diagnosis.MethodsTo identify novel genomic repeat regions, we utilized the IMRS algorithm, with modifications to enable larger target region (100-200bp) identification instead of smaller sequences (18-30bp). These regions enabled customised primer-probe design to suit requirements for qPCR assay. To lower the qPCR amplification times, the assay was conducted using fast cycling condition. Regression analysis, and qPCR data visualization was conducted using Python programming.ResultsUsing Schistosoma mansoni and S. haematobium, we found that IMRS-based qPCR, employing genus-specific primers and TaqMan probes, offers exceptional analytical sensitivity, detecting as little as a single genome copy per microliter within 36 minutes.DiscussionThe lowest concentration of DNA detected using IMRS-based PCR and qPCR represented tenfold improvement over conventional PCR. As part of further development, there is a need to compare IMRS-based qPCR against other qPCR methods for Schistosoma spp. Nonetheless, IMRS-based diagnostics promise a significant advancement in bilharzia diagnosis, particularly in low-transmission settings, potentially facilitating more effective control and treatment strategies

Impact of Mothers’ Schistosomiasis Status During Gestation on Children’s IgG Antibody Responses to Routine Vaccines 2 Years Later and Anti-Schistosome and Anti-Malarial Responses by Neonates in Western Kenya

The potential consequences of parasitic infections on a person’s immune responsiveness to unrelated antigens are often conjectured upon in relationship to allergic responses and autoimmune diseases. These considerations sometimes extend to whether parasitic infection of pregnant women can influence the outcomes of responses by their offspring to the immunizations administered during national Expanded Programs of Immunization. To provide additional data to these discussions, we have enrolled 99 close-to-term pregnant women in western Kenya and determined their Schistosoma mansoni and Plasmodium falciparum infection status. At 2 years of age, when the initial immunization schedule was complete, we determined their children’s IgG antibody levels to tetanus toxoid, diphtheria toxoid, and measles nucleoprotein (N-protein) antigens using a multiplex assay. We also monitored antibody responses during the children’s first 2 years of life to P. falciparum MSP119 (PfMSP119), S. mansoni Soluble Egg Antigen (SEA), Ascaris suum hemoglobin (AsHb), and Strongyloides stercoralis (SsNIE). Mothers’ infections with either P. falciparum or S. mansoni had no impact on the level of antibody responses of their offspring or the proportion of offspring that developed protective levels of antibodies to either tetanus or diphtheria antigens at 2 years of age. However, children born of S. mansoni-positive mothers and immunized for measles at 9 months of age had significantly lower levels of anti-measles N-protein antibodies when they were 2 years old (p = 0.007) and a lower proportion of these children (62.5 vs. 90.2%, OR = 0.18, 95% CI = 0.04–0.68, p = 0.011) were considered positive for measles N-protein antibodies. Decreased levels of measles antibodies may render these children more susceptible to measles infection than children whose mothers did not have schistosomiasis. None of the children demonstrated responses to AsHb or SsNIE during the study period. Anti-SEA and anti-PfMSP119 responses suggested that 6 and 70% of the children acquired schistosomes and falciparum malaria, respectively, during the first 2 years of life

Young Adults in Endemic Areas: An Untreated Group in Need of School-Based Preventive Chemotherapy for Schistosomiasis Control and Elimination

Parasitologic surveys of young adults in college and university settings are not commonly done, even in areas known to be endemic for schistosomiasis and soil-transmitted helminths. We have done a survey of 291 students and staff at the Kisumu National Polytechnic in Kisumu, Kenya, using the stool microscopy Kato-Katz (KK) method and the urine point-of-care circulating cathodic antigen (POC-CCA) test. Based on three stools/two KK slides each, in the 208 participants for whom three consecutive stools were obtained, Schistosoma mansoni prevalence was 17.8%. When all 291 individuals were analyzed based on the first stool, as done by the national neglected tropical disease (NTD) program, and one urine POC-CCA assay (n = 276), the prevalence was 13.7% by KK and 23.2% by POC-CCA. Based on three stools, 2.5% of 208 participants had heavy S. mansoni infections (≥400 eggs/gram feces), with heavy S. mansoni infections making up 13.5% of the S. mansoni cases. The prevalence of the soil-transmitted helminths (STH: Ascaris lumbricoides, Trichuris trichiura and hookworm) by three stools was 1.4%, 3.1%, and 4.1%, respectively, and by the first stool was 1.4%, 2.4% and 1.4%, respectively. This prevalence and intensity of infection with S. mansoni in a college setting warrants mass drug administration with praziquantel. This population of young adults is ‘in school’ and is both approachable and worthy of inclusion in national schistosomiasis control and elimination programs

Table_4_Development of a rapid and highly sensitive nucleic acid-based diagnostic test for schistosomes, leveraging on identical multi-repeat sequences.xls

IntroductionSchistosomiasis (Bilharzia), a neglected tropical disease caused by Schistosoma parasites, afflicts over 240 million people globally, disproportionately impacting Sub-Saharan Africa. Current diagnostic tests, despite their utility, suffer from limitations like low sensitivity. Polymerase chain reaction (PCR) and quantitative real-time PCR (qPCR) remain the most common and sensitive nucleic acid amplification tests. Still, the sensitivity of nucleic acid amplification tests is significantly affected by the copy number of amplification targets, resulting in underestimation of true Schistosoma infections, especially in low transmission settings. Additionally, lengthy qPCR run times pose challenges when dealing with large sample volumes and limited resources. In this study, the identical multi-repeat sequences (IMRS) were used as a novel approach to enhance the sensitivity of nucleic acid-based Bilharzia diagnosis.MethodsTo identify novel genomic repeat regions, we utilized the IMRS algorithm, with modifications to enable larger target region (100-200bp) identification instead of smaller sequences (18-30bp). These regions enabled customised primer-probe design to suit requirements for qPCR assay. To lower the qPCR amplification times, the assay was conducted using fast cycling condition. Regression analysis, and qPCR data visualization was conducted using Python programming.ResultsUsing Schistosoma mansoni and S. haematobium, we found that IMRS-based qPCR, employing genus-specific primers and TaqMan probes, offers exceptional analytical sensitivity, detecting as little as a single genome copy per microliter within 36 minutes.DiscussionThe lowest concentration of DNA detected using IMRS-based PCR and qPCR represented tenfold improvement over conventional PCR. As part of further development, there is a need to compare IMRS-based qPCR against other qPCR methods for Schistosoma spp. Nonetheless, IMRS-based diagnostics promise a significant advancement in bilharzia diagnosis, particularly in low-transmission settings, potentially facilitating more effective control and treatment strategies.</p