Biomedical Science

Molecular characterization of rotavirus strains among children under five years presenting with gastroenteritis at Busia county referral Hospital, Kenya

2025-02-11T17:44:37Z

Molecular characterization of rotavirus strains among children under five years presenting with gastroenteritis at Busia county referral Hospital, Kenya NJALALE, Abednego Rotavirus has been found to be the leading cause of severe diarrhea in young children in developing countries, especially in Africa, contributing to 121,000 out of the total childhood deaths. Rotavirus has nine serogroups (A–I), but only groups A, B, and C infect humans. Group A is the most common and is responsible for most severe rotavirus gastroenteritis cases in young children. The introduction of two new live oral rotavirus vaccines, namely Rotarix® and RotaTeq®, was expected to reduce child morbidity and mortality due to rotavirus gastroenteritis. In Kenya, a previous study showed that the prevalence of rotavirus infection is 16%. The vaccine currently administered in Busia County is Rotarix®, which targets the most common strain, G1P[8]. Emerging genotypes could potentially reduce the vaccine's effectiveness. There is no documented data on the prevalence of rotavirus and circulating genotypes in Busia County. The broad objective was the molecular characterization of rotavirus strains circulating in children under five presenting with gastroenteritis at the Busia County Referral Hospital. The specific objectives were to determine the prevalence of circulating genotypes, assess vaccination status against rotavirus, and analyze the phylogenetic relationships among the identified strains. This study was a hospital based cross-sectional descriptive study on 116 patients randomly selected among those presenting with gastroenteritis. A questionnaire was used to determine their clinical and demographic characteristics and vaccination status. ELISA-based kits were used to detect Group A rotavirus antigens. Rotavirus dsRNA was extracted, separated by polyacrylamide gel electrophoresis and visualized by silver staining. Positive specimens were selected, and dsRNA extracted was reverse-transcribed and amplified using semi-nested RT-PCR in the presence of original consensus primers and genotyped using a mixture of serotype specific primers for the rotavirus genes specifying G (gene 9) and P (gene 4) classification. Phylogenetic analysis was conducted using the neighbor-joining method with MEGA software, and bootstrap analysis was performed with 1000 replications, following sample collection, RNA extraction, and sequence alignment. The prevalence of rotavirus in the study was 50.9%. The most affected age group was 7 – 12 months constituting 33.9% of the positive cases. There were more males (52.5%) than females (47.5%) infected with rotavirus. The vaccination rate was 31%. The G1P[8] genotype was the most predominant (52.5%), followed by G3P[6](20.3%), G2P[4] at (15.3%), G9P[8] (5.1%), G1,3P[6] (3.4%) and G1P[4] (3.4%) respectively. G1P[8] was common in both vaccinated and unvaccinated patients but was more prevalent in vaccinated individuals and appeared mostly in the lower severity scores indicating a less severe disease. The G3P[6] genotype accounted for 20.3% of the total infections and was higher in unvaccinated individuals, suggesting that this it may be less affected by the current vaccination regime. The G3P[6] genotype had more patients with higher severity scores (7 and 8), indicating more serious disease. Phylogenetic analysis of the circulating strains revealed that there is a high sequence similarity among many of the identified strains. The presence of multiple genotypes and slight genetic variations means that vaccines need to account for this genetic diversity, possibly due to ongoing viral evolution and adaptation. The study revealed the prevalence of rotavirus, the presence of various strains and the low vaccination coverage. These findings underscore the importance of widespread rotavirus vaccination that covers all strains. The study recommends that intervention be taken by implementing community-based programs to improve sanitation and hygiene practices, which can help reduce rotavirus transmission, as well as evaluating the effectiveness of the current vaccine, Rotarix®, against the various genotypes identified. More robust efforts also need to be put in place to increase vaccination coverage against rotavirus in the county, focusing particularly on the most affected age group, 0-12 months. Additionally, comparative genomic studies should be conducted to understand the genetic variations and evolutionary relationships among the rotavirus strains. Master's Thesis

Assessment of plasmodium species prevalence, antimalarial drug resistance genes and gametocytes in malaria infectionsbetween 2018 and 2021 in Kombewa sub-county, Kenya

2024-12-02T13:57:57Z

Assessment of plasmodium species prevalence, antimalarial drug resistance genes and gametocytes in malaria infectionsbetween 2018 and 2021 in Kombewa sub-county, Kenya Chemwor, Gladys Chebet In Western Kenya, malaria is a major cause of morbidity and mortality with more than 70% of the population at risk.Its decline over the last 25 years indicates a shift to older children majority of who are asymptomatic. Kenya uses artemisinin combination therapy (ACT) specifically artemether-lumefantrine (AL) as first line for treatment of malaria infections and sulfadoxine-pyrimethamine (SP) as prophylaxis in pregnant women. However, delayed parasite clearance has been observed in Kenya. Resistance to antimalarials specifically ACT‟s and SP is associated with various polymorphisms in P. falciparum multidrug resistance gene 1 (Pfmdr1), multidrug resistance-associated protein 1 (Pfmrp1), dihydrofolate-reductase (Pfdhfr), dihydropteroate-synthase (Pfdhps), and chloroquine resistance transporter (Pfcrt) genes. While symptomatic malaria infections are recognized and treated, recent reports have revealed a largeproportion of asymptomaticinfections.A recent study in Kombewa indicated that some asymptomatic participants did not clear parasites or disrupt transmission in a large proportion of study population despite adequate treatment. Given the limited data on drug resistance in asymptomatic infections, molecular epidemiological studies of drug resistance are required to assess these infections. The first objective was to determine Plasmodium species prevalence (P.falciparum, P.malarie, P.ovale wallikeri, P.ovale curtisi- Pf, Pm, Pow, Poc), second objective was to determine frequency of anti-malarial resistance gene polymorphisms and third objective was toinvestigate gametocyte variability in symptomatic and asymptomatic infections. In a retrospective cross-sectional study molecular techniqueswere used toanalyze 230 archived whole blood samples collected between 2018 and 2021 in Kombewa under malaria epidemiology surveillance and malaria transmission study representing symptomatic and asymptomatic infection. The species composition(Pf, Pm, Pow, Poc) and gametocyte carriage (Pfs16, Pfs25) were determined using real-time polymerase chainreaction and analyzed using excel.Genotyping of Pfmdr1 86, 184 & 1246; Pfmrp1 437, 876 &1390; Pfdhfr 16, 22, 59 & 164; Pfdhps 436, 437 & 581, and Pfcrt 72, 76, 271, 326, 356 single nucleotide polymorphisms (SNPs)were assayed using Mass ARRAY platform and analyzed against the reference 3D7 genome. Data and statistical analysis wasdone using excel and Chi square tests in STATA.Of the 230 samples analyzed, Plasmodium species prevalence was; Pf 64.35% (148/230), Pm 26.52%, (61/230), Pow 9.57% (22/230), Poc 6.09% (14/230).The symptomatic Pf comprised 70.59% (24/34), Pm 17.65% (6/34), Poc 11.76% (4/34), and Pow 8.82% (3/34) while for asymptomatic Pf 63.27% (63/196), Pm 28.06% (55/196), Poc 5.1% (10/196), and Pow 9.69% (19/196). Co-infections were higherfor Pf/Pm; symptomatic 11.76% (4/34), asymptomatic 19.39% (38/196) compared to all the other species combinations (≤6%).The Pfmdr1_184 harbored symptomatic 68.75% (11/16) and asymptomatic 52% (26/50) mutations, while Pfmdr1_1246 had 6% mutants in both symptomatic (1/16) and asymptomatic (2/30).For Pfmrp1 gene codon 437 had no mutations in symptomatic while asymptomatic had only one mutation (1/30). Pfmrp1 codon 876, symptomatic reported 47.05% (8/17) & asymptomatic 37.93% (11/29). Pfmrp1 1390 symptomatic had 6.67% (1/15) and asymptomatic 6.9% (2/29) mutations respectively. Pfdhfr codons 16 and 22 had no mutations for symptomatic and asymptomatic. Pfdhfr 59 & 164 had 88.24% (15/17) and 90.91% (30/33) mutants for symptomatic and asymptomatic respectively. For both symptomatic and asymptomatic Pfdhps codons 436, 437 and 581 did not reveal any mutants.The Pfcrt gene, codons72, 76, & 356 did not have any mutations for either symptomatic or asymptomatic. Pfcrt 326 & 371 had 3.23% (1/31) and 11.11% (4/36) mutations in asymptomatic only.Overall gametocyte carriage was 65.65% (151/230), symptomatic cases positives werePf16 85.29 (29/34); Pf25 79.41% (27/34); Pf16Pf25 93.1% (29/29) while asymptomatic had Pf16 68.88% (135/196); Pf25 67.86% (133/196) &Pf16Pf25 86.1% (124/144). Even though proportional comparisons did not reveal statistical significance, this study was critical in revealing variations of Plasmodium species prevalence, frequency of drug resistance markers, and gametocyte variability in symptomatic and asymptomatic infections. Findings highlight the need for heightened molecular surveillance and management of malaria infectionsfor timely and informed interventions in all infections. Master's Thesis

Profile of drug resistance conferring gene mutations in Mycobacterium tuberculosis among new and previously treated pulmonary tuberculosis cases from Kisumu county, Kenya

2023-12-18T16:42:45Z

Profile of drug resistance conferring gene mutations in Mycobacterium tuberculosis among new and previously treated pulmonary tuberculosis cases from Kisumu county, Kenya OGUMBO, Fredrick Abonyo Tuberculosis (TB) remains a significant public health concern in Kisumu County, Kenya, with a high burden of drug-resistant cases. Existing studies focus on epidemiological aspects, but lack comprehensive investigation into the genetic basis of drug resistance. This research gap hinders the development of targeted interventions and strategies for effective TB control in Kisumu County. This study aimed to investigate the profile of drug resistance-conferring gene mutations in Mycobacterium tuberculosis among new and previously treated pulmonary tuberculosis cases in Kisumu County, Kenya. Specifically, the study aimed to establish drug resistance conferring gene mutations in M. tuberculosis from HIV cases; determine gene mutations in M. tuberculosis that confer resistance to first and second line TB treatment; evaluate the diagnostic performance of molecular line probe assay in M. tuberculosis drug resistance testing among new and previously treated pulmonary TB cases in Kisumu County, Kenya. In this hospital and laboratory based cross- sectional study, sputum samples were collected from 256 TB clinical suspects attending various health facilities in Kisumu County between November 2020 and October 2021. Bacteriological and molecular techniques, including line probe assays, were employed to identify gene mutations and drug resistance patterns. Line probe assay assessed mutations in the genes rpoB, katG, inhA, embABC, pncA, rrs; gyrA, gyrB, and eis. Using statistical package for the social sciences v23, data was descriptively analysed into frequencies and proportions. Binary logistic regression was used to model for predictors of drug resistance while cross tabulation was used to describe mutant patterns. Contingency table was used to assess sensitivity, specificity, PPV and NPV. Out of a sample of 256 from TB suspected cases, 145(56.6%) were confirmed cases of which 113(77.9%) retreatment. Greater variability of mutations was exhibited from HIV positive cases compared to HIV negative cases and age was a predictor to isoniazid resistance, rifampicin resistance(RR) and Multidrug resistance (MDR). Low INH resistant strains had alterations in the promoter region of inhA gene at codon -15 indicating amino acid change of S315T1. High INH resistant strains showed mutations at katG gene, codon 315. The study presented that 2 MDR, 4 RR and 4 high INH resistance had the same nucleotide and amino acid changes and higher number of unknown mutations were exhibited in retreatment cases compared to new cases. Using phenotypic drug susceptibility testing as surrogate marker, genotypic test showed a statistical significant relationship with phenotypic method for detection of INH resistance (p=0.001), RIF resistance (p=0.001) and MDR (p=0.001). Understanding the genetic basis of drug resistance is crucial in guiding appropriate targeted treatment strategies and mitigating the spread of drug resistant strains. The results from the study will also guide policies and TB programs in regional specific anti-TB regimen based on mutation patterns, strengthen TB surveillance, and increase array of TB drug resistance diagnostic options for implementation by County and National governments in Kisumu County, Kenya. PhD Theses

Use of conventional and molecular techniques to Determine the prey alence of shigella and Enteroinv asive escherichia coli strains from Diarrhoea patients in selected health facilities in Rural western Kenya

2022-05-17T06:22:34Z

Use of conventional and molecular techniques to Determine the prey alence of shigella and Enteroinv asive escherichia coli strains from Diarrhoea patients in selected health facilities in Rural western Kenya OCHIENG, John Benjamin Diarrhoea is a major cause of infant morbidity and mortality worldwide. It accounts for 1.6- 2.5 million deaths annually and each child in the developing world experiences an average of three episodes of diarrhoea per year. Shigella spp and enteroinvassive Escherichia coli (EIEC) are common etiologic agents of bacillary dysentery. Currently, conventional culture techniques for identifying Shigella spp from stool has low sensitivity since the diagnosis is often obscured due to the presence bf low number of causative organisms, competition from commensals and inappropriate sample collection. The aim of this study was to determine the prevalence of Shigella and EIEC using conventional culture method and molecular technique targeting the ipaH gene, common to both Shigella spp and EIEC. Stool specimens from 440 patients of all ages presenting to nine health facilities with diarrhoea.were investigated for Shigella species and EIEC by conventional culture and a subset of the specimens evaluated by molecular technique. Of the 440 specimens cultured, 48 (10.9%) yielded Shigella species; S. flexneri (56%), S. dysenteriae non-type 1 (25%), and S. boydii and S. sonnei (8.3% each). No EIEC strains were isolated. Of the 421 specimens evaluated by PCR, 78 (18.5%) tested positive for ipaH gene, 331 (78.6%) tested negative, and 12 (2.9%) were weakly positive. All the Shigella species (100%) isolated by culture and an additional 33 (7.8 %) cases not identified by culture, were detected by ipaH PCR. Bloody specimens were more likely to yield a Shigella by culture (56%) and PCR (35%) than other types of diarrhoea (P<0.05). The findings of this study demonstrate that the magnitude of shigellosis in rural western Kenya is much higher than previously thought. Information from this study will help in evaluating the need to strengthen the basic preventing measures and other control measures against these pathogens.

Temporal and spatial trends of plasmodium falciparum multi-drug resistance protein 1 gene mutations during implementation of artemisinin combination therapies between 2008 and 2019 in Kenya

2022-05-11T09:02:49Z

Temporal and spatial trends of plasmodium falciparum multi-drug resistance protein 1 gene mutations during implementation of artemisinin combination therapies between 2008 and 2019 in Kenya OKORE, Winnie Adhiambo Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been associated with conferring resistance against artemisinin and its partner drugs in Southeast Asia (SEA) and there are concerns of resistance spreading to Africa as the previous patterns. With no suitable replacement for artemisinin combination therapies (ACTs), establishing the frequency of these polymorphisms contributing to impaired response to ACTs is key for continued drug resistance surveillance in Africa, where the few putative Kelch 13 propeller polymorphisms reported in Rwanda and the horn of Africa have not affected ACTs tested and used there. Apart from Kelch 13, Pfmrp1 gene is also a potential drug resistance marker neglected in Kenya as compared to chloroquine (CQ) and sulfadoxine pyrimethamine (SP) targets. The frequency of Pfmrp1 SNPs associated with anti-malarial resistance and correlation with in vitro drug sensitivities from Kenyan parasite isolates between 2008 and 2019 is not known. Of particular interest between 2008 and 2019 was a representation of the transition period and post-ACTs timelines of the study period, to compare the trends over time to help understand the prevalence of resistance. Therefore the general objective of this study was to investigate the temporal and spatial trends of the Pfmrp1 gene mutations during the implementation of ACTs between 2008 and 2019 in Kenya. The specific objectives were to determine the frequency of SNPs of Pfmrp1 gene, determine in vitro Plasmodium falciparum (P.f.) drug response patterns and establish the correlation between the polymorphic versus wild-type and in vitro anti-malarial response profiles for the Kenyan field isolates collected between 2008 and 2019. In a cross-sectional retrospective study of 6 months and older participants, 300 samples collected from 6 sites across Kenya namely; Kisumu, Kombewa, Malindi, Marigat, Kisii and Kericho between 2008 and 2019 under an ongoing, epidemiology of malaria and drug resistance patterns in Kenya study, were assayed for SNPs in Pfmrp1 gene codons; H191Y, S437A, I876V and F1390I using Agena MassARRAY platform. Field isolates were also tested against standard antimalarials selected; artemisinin (ART), lumefantrine (LU), amodiaquine (AQ), mefloquine (MQ), quinine (QN) and CQ to determine their in vitro drug sensitivity using the malaria SYBR Green I-based fluorescence assay. Categorical data was analyzed as proportions, while the continous data was reported as median IC50 values. Of the 300 samples typed, polymorphisms at Pfmrp1 codon I876V was the most frequent at 58.9% (162/275) mutants followed by F1390I, 7.1% (19/267) and S437A, 3.3% (9/274) while H191Y was the least at 3.1% (5/151). The antimalarial sensitivity patterns of AQ and QN were shown to have median IC50s that increased over time between 2008 and 2019 from 2.959ng/ml [IQR=2.453-4.189, n=47] and 1.967ng/ml [IQR=1.332-3.243, n=54] to 7.111ng/ml [IQR=6.562-9.054, n=11] and 3.046ng/ml [IQR=2.178-6.175, n=20] respectively. MQ appeared to be undergoing positive selection, it was shown to have median IC50s that increased resistance over time from 16.59ng/ml [IQR=12.13-35.96, n=16] to 20.32ng/ml [IQR=12.54-23.12, n=5] and it increased significantly (P<0.0001) during the same period. However, LU showed contradicting results of increased sensitivity and resistance over time during the study period. The correlation of infections with mutation at codon I876V were associated with higher QN and LU with 50% inhibition concentration during in vitro tests, suggesting reduced sensitivity. Identifying these markers are critical to understanding and tracking other rising prevalence of ACTs resistance within this region after its implementation besides, is essential as prerequisites for any control and elimination programs. Study findings showed early indicators signaling resistance patterns to ACTs and selection should be tracked. Pfmrp1 gene mutations should also be tracked as an important candidate gene for monitoring drug resistance in Kenya.

Molecular analysis of HIV mutations and determination Of subtypes circulating in gem, western Kenya

2022-04-25T07:50:07Z

Molecular analysis of HIV mutations and determination Of subtypes circulating in gem, western Kenya JALENY, Ochieng Paul As the HIV pandemic becomes increasingly complex and devastating in Africa, there is need to come up with better management strategies in terms of treatment, vaccine and better testing methods. However, this is getting hampered by the high diversity of Human Immunodeficiency Virus type 1 (HIV -I), which is brought about by high rate of replication and mutation. Such mutations may cause antiretroviral drug resistance if they occur in the gene regions coding for molecular drug targets. The high rate of mutation also leads to many viruses which are genetically related but distinguishable variants and subtypes. In this study, molecular analysis of the protease and reverse transcriptase gene sequences of the HIV -I in plasma samples collected from Gem in western Kenya was done. Sequencing of these genes was done with the aim of identifying mutations and analyzing each for antiretroviral drug resistance. Also, determination of the subtypes based on these sequences was done. A total of 30 samples were taken for sequencing, however, 9 of them had primer failures and therefore did not successfully sequence, leaving only 21 samples for molecular analysis. The results showed several mutations in these gene sequences, and analysis of each of the mutation for drug resistance showed none to be causing resistance to any of the known classes of ARV drugs. For the phylogenetic analysis, 16 (76.2%) of the isolates were found to be subtype A, subtype D were 4 (19.0%), and the remaining I (4.8%) was circulating recombinant form, CRF _AD. To verify the results, control sample was analyzed by both TruGene and ill-house methods and both gave the same results. Since this study revealed three different HIV-I subtypes in Gem, it would be necessary to conduct a future study to find out the effect of these subtypes on the transmission, pathogenicity and the rate of HIV-I disease progression in Gem, western Kenya.

Mechanisms Responsible for Insecticide Resistance in Anopheles Gambiae S.L. Populations of AHERO, BUDALANGI and BUNGOMA in Western Kenya

2022-04-13T09:13:22Z

Mechanisms Responsible for Insecticide Resistance in Anopheles Gambiae S.L. Populations of AHERO, BUDALANGI and BUNGOMA in Western Kenya OCHOMO, Eric Odhiambo As malaria control interventions directed against Anopheles vectors through the distribution of insecticide-treated bednets (ITNs) and application of indoor residual sprays (IRS) increase in sub-SaharanAfrica, it is crucial to continually assess the efficacy of these main insecticide-based interventionsagainst local malaria vector populations. In western Kenya, I'fN use is widespread and the area has experienced a scale-up of IRS in targeted districts in the past few years. Resistanceoflocal vectors to the insecticides used in ITNs and IRS could lead to failure of these interventions leading to increase in malaria infections. This study investigated susceptibility ofAnopheles gambiae and Anopheles arabiensis, to two pyrethroid insecticides (permethrin and deltamethrin) currently used in ITNs and IRS in western Kenya and one carbamate insecticide (bendiocarb), which is a potential alternative to pyrethroids for IRS. The study also investigated the resistance mechanisms exploited by the vectors: biochemical resistance pathways which include elevation in detoxification enzymes (esterases, oxidases, and GSTs) and molecular pathways, in this case, the genetic acquisition, and spread of the knock-down resistance (kdr) genotype. For testing, adult mosquitoes from either larva samples collected in the field or Fls raised from blood-fed females collected from houses were used. Samples were collected from threesites in western Kenya: Ahero, Budalangi, and Bungoma. Two techniques; the CDC bottle assay and the WHO tube assays were used to determine susceptibility of vectors while microplate enzyme assays and Real-time PCR techniques were used respectively to investigate the biochemical and molecular mechanisms responsible for any observed resistance in the vectors. All samples were identified to species level by standard PCR. Out of a total of 3,315 mosquitoes used, 1124 were from Bungoma (77% A. gambiae s.s. and 23% A. arabiensisi, 885 from Budalangi (1% A. gambiae s.s. and 99% A. arabiensisi and 1102 from Ahero (100% A. arabiensisi. There was high resistance to the pyrethroids it)An. gambiae s.s. populations from Bungoma (permethrin 62.0%, deltamethrin 34.0%) and Bundalangi (permethrin 26.0%) while therewas little or no resistance to Bendiocarb in the two sites. Samples from Ahero were found to have little or no resistance to all 3 insecticides tested. Female mosquitoes showed lower susceptibility to insecticides compared to males (P=0.0127). There was no significant difference between the CDC Bottle and WHO tube bioassay methods in determining the resistance status of vector populations (P=0.2446). The kdr L1014S allele approached fixation in A.. gambiae S.s. populations of Bungoma (99.4%) and Budalangi (100%) while none of the An. arabiensis tested had the kdr genotype. Permethrin-resistant A. gambiae s.s. from Bungoma had 1.65 fold elevation in non-specific esterases but no elevation was found in resistant populations from Budalangi. Over 70% of households in all sites were covered with ITNs with coverage in Ahero being highest at 85%. The IRS was only performed in Ahero in 2010 had a coverage of 58.0% among the households sampled. This study confirms the presence of insecticide resistance to pyrethroids in western Kenya, with Bungoma having the highest level of resistance compared to the other 2 study sites. Either CDC Bottle assay or WHO tube bioassay techniques can be used to accurately diagnose and monitor insecticide resistance. The high resistance seen in Bungoma can be attributed to a combination of two resistance mechanisms, the elevated esterases, and high frequency of kdr. The elevated esterases are most likely due to the high rate of organophosphate insecticides use in the area for tobacco farming. These findings will inform selection of insecticides for IRS so as to effectively control pyrethroid resistant vectors and curb the spread of insecticide resistance.

Immunophenotypic Characterization of Lymphocyte Subsets -Expressing Programmed Death-L (Pd-L) in Individuals Exposed to Differential Malaria Transmission Patterns and Endemic Burkitt's Lymphoma

2022-04-06T07:34:30Z

Immunophenotypic Characterization of Lymphocyte Subsets -Expressing Programmed Death-L (Pd-L) in Individuals Exposed to Differential Malaria Transmission Patterns and Endemic Burkitt's Lymphoma OGOLLA, Sidney Onyango Repeated..challenge'of the immune system by chronicexposure to high antigen.levels due to persistent infection may lead to development of impaired T-cells that are not effective in . . . . .' \ mediatingimmune functions. Malaria and EBV are two agents that have been implicated in the aetiologyof Burkitts lymphoma. However, the' precise mechanism is unknown but exhaustion/impairementof immune cells has been implicated. Programmed death-I (PD-l) is an . : .. .' immuneinhibitory molecule that negatively regulates activated immune cells.upon interacting withitsIigands.programmed death ligand-I (PD-Ll) and programmed death ligand-Z (PD-L2) resultingin down-regulation of immune responses. Previous studies in murine and primate viral andparasitic diseases have reported the up-regulation of PD-l and sclublePfr-I (sPD-l) but no studieshave reported the expression of PD-l' in individuals from areas.with divergent malaria transmissiofldynamics or in children presentingwith endemic Burkitt'sIymphoma (eBL). A cross-sectional study was carried out in three distinct populations; Kokwet (unstable P. . :." '. . . jalciparumtransmission), Kanyawegi (malaria holoendemic) regions.of Western Kenya and childrenwith' eBL from New Nyanza Provincial General Hospital. PBMC's 'were stained for lymphocyteand PD-l expression markers and data .acquiredusing a four color fiowcytometer. In addition, soluble PD-l in plasma was quantified by Enzyme Linked Immunosorbent Assay (ELISA)in individuals from Kanyawegi, Kokwet andBL. This study reports an increased expressionofPD~l in Kanyawegi compared to Kokwet [(CD4+;p

Evaluation of the Repellency Effectiveness of Linalool and Metofluthrin against Anopheles Gambiae S.L. in Kisian Village, Western Kenya

2022-04-05T08:43:48Z

Evaluation of the Repellency Effectiveness of Linalool and Metofluthrin against Anopheles Gambiae S.L. in Kisian Village, Western Kenya KOSGEI, Jackline Jeruto Malaria continues to pose a major public health threat. Despite the efforts that have been made to prevent humans from mosquito bites, changes in the vector biting behavior, and mosquitoes tending to bite earlier before bed time could lead to successful malaria transmission. Vector control for the prevention of malaria has relied mainly on the use of chemical insecticides with extended residual life on walls or nets. These Insecticides act to some extent through repellent properties which has spurred increased interest in spatial repellents. In Kisian village, insecticide-treated nets (ITNs) have been scaled up. The main malaria vectors in this area are Anopheles gambiae s.1. The objective of this study was to test the effectiveness of two outdoor repellents; Linalool and Metofluthrin and four indoor formulations of Linalool repellent namely: natural Linalool, synthetic Linalool, 70-80% dLinalool and 55% d-Linalool in selected houses in a village located west of Kisumu town near KEMRI's Center for Global Health Research. A cross-over design study was carried out in 80 pairs of houses within this site. Half of the randomly selected houses were provided with Linalool in a gel emanator placed on top of the partitioning wall inside the houses while the other half were not given any treatment. Natural Linalool and synthetic Linalool formulations were evaluated during the short rains while the 70-80% d-Linalool and 55% dLinalool formulations were evaluated during the long rains. All houses were grouped in two sets. During the first evaluation, houses in set 1 received Linalool repellent and during the second evaluation, houses in set 2 were treated with Linalool repellent while the rest of the houses served as controls. Houses were sampled for mosquitoes each morning for two days in a week during the rainy season by pyrethrum spray catches (PSC) and the data collected from each house was entered into PDAs. To further assess the effectiveness in these spatial repellents in deterring outdoor host-seeking females from the host, three tents were used each night outside the houses. The tents were located at least 100 m apart. One repellent formulation (Linalool or Metofluthrin), was placed on poles approximately 1 meter high next to one of two tents and the third tent was not treated. Volunteers remained inside the tents from 7pm until 7am. At 7am, they collected mosquitoes from the tent traps using mouth aspirators and transferred them to paper cups labeled with date of collection and the tent from -which the mosquitoes were collected. All the data entered in the PDA were downloaded into a database on a secure server and data from the outdoor collections were entered using visual CE and appended to the same database. Poisson regression was used for data: analysis. Analysis was done using univariate procedure in SAS version 9.1. The major findings of this study is that lTN and 70-80% d-Linalool combined reduced Anopheles mosquito densities by 49% in treated houses relative to untreated controls (RR=0.49; CI, 95% 0.25-0.97; P=0.04). ITN and 70-80% d-Linalool combination reduced the density of fed Anopheles mosquitoes compared to ITN-55% d-Linalool treatment combinations (mean difference=-0.19; P< 0.0001) compared with ITN only, 70-80% and ITN (RR=0.73; CI, 95% 0.53-0.99; P=0.04) and Natural linalool and ITNs (RR=0.61; Cl, 95% 0.41-0.92; P=0.02) reduced densities of fed and half-gravid mosquitoes but all treatments had no effect on reducing the number of blood-fed Anopheles mosquitoes during the long rains. Tents treated with linalool had higher numbers of mosquitoes compared to tents with no treatment (RR=1.61; CI, 95% 1.27-2.05; P=O.OOOl). In conclusion, this study found Linalool and Metofluthrin repellents not effective in reducing indoor and outdoor densities of Anopheles mosquitoes while ITNs remain to be effective in the control of malaria vectors. The results from this study provide important information for malaria programs that aim at finding effective repellents for the control of malaria.

Lack of Association between Interleukin-6 (-174g/C),Interleukin-Io (-1082a/G, -819c/T, And -592c/A) Polymorphisms and Susceptibility to Endemic Burkitt Lymphoma in Children Aged between 5-8 Years from Western Kenya

2022-03-19T08:36:36Z

Lack of Association between Interleukin-6 (-174g/C),Interleukin-Io (-1082a/G, -819c/T, And -592c/A) Polymorphisms and Susceptibility to Endemic Burkitt Lymphoma in Children Aged between 5-8 Years from Western Kenya ODUOR, Cliff Isaya Endemic Burkitt lymphoma (eBL) is the most common paediatric cancer in sub-Saharan Africa and occurs at a high incidence in western Kenya. The tumour has the highest proliferative rate of any other human cancer. Although EBV and malaria co-infections appear to be primary factors in the aetiology of eBL, host genetic contributions that renders some children permissive to this pathologic pathway remains to be elucidated. Cytokine signals have the potential to be deletious in the context of lymphoma development by acting as growth facts and promoting tumour cell survival. Over expression of IL-6 and IL-I0 is suspected to playa role in the pathogenesis of eBL. It has been shown that genetic variants within the IL-6 and IL-IO gene promoters correlate with elevated levels of these cytokines, but whether these SNPs confer risk to eBL development is unknown. Children genetically predisposed to produce elevated levels of these cytokines may be more susceptible to eBL development. This case-control study investigated the association between the IL-6 (174G/C) and IL-IO (-1082A1G, -819Crr and -592C/A) promoter polymorphisms and susceptibility to eBL and whether these polymorphisms influence EBV loads in children (n=205) from western Kenya. DNA samples from 117 eBL cases and 88 healthy agematched controls were used in the analysis. A real-time polymerase chain reaction (PCR) using TaqMan allelic discrimination assay was used for genotyping. The EBV loads were measured using quantitative real-time PCR. The distribution of IL-6 and IL-IO genotypes was compared using X2 test. Across group comparisons were evaluated using Kruskal-Wallis test, while the association between the polymorphisms/haplotypes and susceptibility to eBL was determined using logistic regression analyses. Results showed comparable frequencies for IL-6 and IL-I0 genotypes between the cases and controls. Logistic regression analysis demonstrated that the individual IL-6 -174G/C (p=0.080), IL-I0 -1082A1G (p=0.900), 819Crr (P=O.541)and -592C/A (P=O.541) genotypes and the -1082A1-S19C/-592C (ACC) [p=0.671], ATA [P=O.356] and GeC [p=0.708] haplotypes were not associated with susceptibilityto eBL or increased EBV load. Results from this study do not eliminate a role for IL-6 and IL-IO in eBL pathogenesis however these common polymorphisms do not predisposeto eBL development. The baseline information from this study necessitates future studiesto explore other genetic variants regulating immune mediators that could contribute to eBLcarcinogenesis.