Medical Immunologyhttps://repository.maseno.ac.ke/handle/123456789/11522024-03-29T06:08:58Z2024-03-29T06:08:58ZAssociation of genetic variants in IL7 and CSF2 with Plasmodium Falciparum Malaria outcomes in children attending Siaya county referal HospitalKISIA, Lily Elaziahttps://repository.maseno.ac.ke/handle/123456789/59102023-12-19T15:33:46Z2023-01-01T00:00:00ZAssociation of genetic variants in IL7 and CSF2 with Plasmodium Falciparum Malaria outcomes in children attending Siaya county referal Hospital
KISIA, Lily Elazia
Immune naïve children residing in endemic Plasmodium falciparum (P. falciparum) transmission regions experience repeated episodes of malaria infection that may lead to bone marrow suppression and subsequently severe malaria anemia that is responsible for the high morbidity and mortality in these regions. Genetic variation in cytokine genes play a key role in influencing malaria infection outcomes by altering production of immune inflammatory mediators. The current study determined the association of genetic variants in IL7 (72194T>C and -2440A>G) and CSF2 (-7032G>A, and 64544T>C) with P. falciparum malaria infection outcomes in children attending Siaya County Referral Hospital (SCRH). Specifically, the study assessed the associations of genetic variants in IL7 with susceptibility to inefficient erythropoiesis (IE) and SMA; the influence of genetic variants in CSF2 on the rate of malaria infections and SMA episodes; the relationship between genetic variants in CSF2 and the risk of malaria infections and SMA episodes; and genetic variants in CSF2 and the risk of all-cause mortality, in falciparum parasitemic children (aged <36 months). The study designs were cross-sectional case control to achieve objective 1 (n=883) and longitudinal case control to achieve objectives 2-4 (n=1654). The current study utilized the archived samples ((n=2537) obtained from children enrolled in 2009-2012 in a study that evaluated genetic basis of SMA in children attending SDH. Genomic deoxyribonucleic acid was extracted from buccal swabs using the Gentra System and genotyped using a TaqMan 5’ allelic discrimination Assay-By-Design method. Cross-sectional data was analyzed using SPSS (Version 24.0) while longitudinal data was analyzed using R (version 3.1.4). One-way analysis of variance and Student’s t-test were used to compare means. Mann-Whitney-U test was used for pairwise comparisons of median. Chi square and Fisher’s exact test were used to find differences in proportions of genetic variants. Binomial logistic regression was used to determine associations of genetic variants in IL7 with susceptibility to IE and SMA. Poisson regression was used to determine the influence of genetic variants in CSF2 on the rate of in malaria infections and SMA episodes. Cox proportional hazard model was used to determine the relationship between genetic variants in CSF2 and the risk of malaria infections, SMA episodes and all-cause mortality. P values ≤0.05 were considered significant. The results showed that carriage of IL77 2194 TC genotype was associated with enhanced susceptibility to IE (Odds ratio (OR) =1.90; 95% (confidence interval (CI) 1.09–3.30; P=0.02) as was homozygous CC genotype (OR 5.14; 95%CI=1.20–21.99; P=0.03). Individuals with the IL7 CA haplotype had an increased risk of IE (OR=1.90; 95%CI=1.10–3.30; P=0.02), whereas TA haplotype carriers were protected against IE (OR=0.24; 95%CI=0.06–1.21; P=0.05). Further, a decreased incidence rate ratio (IRR) for malaria was conferred by inheritance of the CSF264544 TC genotype (P=0.02) and CSF2 AC/GC diplotype (P<0.01). An increased IRR for malaria was observed in carriers of the CSF2 AT/GC diplotype (P=0.02), while the inheritance of the CSF2 AT haplotype increased the IRR for SMA (P=0.01). Decreased hazard rates (HR) for malaria were observed among CSF2 AC haplotype carriers (P<0.01) while inheritance of the CSF2-7032 GA genotype increased the HR for all-cause mortality (P=0.03). Cumulative results showed that variation in IL7 gene is associated with erythropoietic responses in children with falciparum malaria while variation in CSF2 gene influences susceptibility to malaria, SMA, and all-cause mortality, suggesting that genetic variations in IL7 and CSF2 are potential modulators and or predictors of malaria infection outcomes in young children residing in malaria endemic areas. The findings highlight novel immuno-genetic associations with malaria infection, IE, SMA and all-cause mortality that have potential to guide immunotherapy and vaccine design for severe malaria in young children.
PhD Theses
2023-01-01T00:00:00ZHistopathological assessment of endometrial biopsies, their indication and associated factors among women attending Moi teaching and referral hospital, KenyaANDESO, Gracehttps://repository.maseno.ac.ke/handle/123456789/52232022-05-09T12:07:42Z2021-01-01T00:00:00ZHistopathological assessment of endometrial biopsies, their indication and associated factors among women attending Moi teaching and referral hospital, Kenya
ANDESO, Grace
Endometrial diseases are among the most common gynecological disorders affecting women both globally and locally; accounting for 60% of global maternal deaths. Kenya is ranked thirteenth out of 181 countries with the highest maternal mortality globally. Endometrial disorders such as hyperplasia’s, neoplastic, inflammatory and pregnancy related conditions of the endometrium have been reported to increase with demographic traits such as maternal age and parity. Other risk factors for endometrial disorders include changes in lifestyle, increase in lifespan and the use of hormonal replacement therapy among post-menopausal women. Histopathological evaluation of endometrial samples is a vital tool for early diagnosis of endometrial disorders.
2021-01-01T00:00:00ZB cell response to schistosome antigens in adult Males occupationally exposed to s. Manson In Western KenyaONGURU, Daniel Gunguhttps://repository.maseno.ac.ke/handle/123456789/51972022-04-25T12:44:10Z2010-01-01T00:00:00ZB cell response to schistosome antigens in adult Males occupationally exposed to s. Manson In Western Kenya
ONGURU, Daniel Gungu
Increasing levels of membrane CD23 (CD23) on B cells and soluble CD23 (sCD23) in
plasma are related to development of resistance to re-infection with: Schistosoma mansoni.
However, the mechanisms underlying CD23 expression on B cells remains less understood. In
this study, in vitro B cell response to crude schistosome antigen stimulation as well as sCD23
and IgE levels in plasma and culture supernatants from S. mansoni exposed male adults were
investigated. Blood was obtained from 34 adult males occupationally exposed as car washers
or sand harvesters along the shores of Lake Victoria in Kisumu. Peripheral blood mononuclear
cells (PBMCs) were isolated from heparinized fresh blood and B cells were obtained from the
PBMCs by negative selection using magnetic bead separation. B cells were cultured at
approximately 20xl06 cells/mL for 5 days in RPMI-1640 alone or with soluble egg antigen
(SEA), soluble worm antigen preparation (SWAP), recombinant IL-4 (rIL-4) and anti-CD40
mAb (each alone, and, the first two in combination with one or both of the third and fourth). To
determine whether B cells respond differently in pureculture or in PBMC, some 7 PBMC
cultures were stimulated under similar conditions with pokeweed mitogen (PWM), anti-IgE
mAbs, SWAP, SEA, or phytohaemagglutinin (PHA). B cell expression of membrane-bound
CD23 was determined by flow cytometry using FACSCalibur (Becton Dickinson) while the
quantitative release of sCD23, and IgE in cell-free culture supernatants and plasma were
measured by direct ELISA. Flow cytometry data was analyzed on FlowJo (Treestar, 2008) .
.Regression, correlation and ANOV A analyses were done using GraphPad Prism software v. 5.
Both CD23 expression on B cells and sCD23 release into culture supernatants were
.significantly raised in the presence of SEA, rIL-4 and anti-CD40 mAb. The expression of
CD23 on B cells was inversely proportional to sCD23 levels, directly related to IgE levels but
unrelated to S. mansoni egg counts in stool, but these observations were not statistically
significant (p>0.05). The factors involved in CD23 cleavage from cell surfaces and further
breakdown remain unclear and warrants detailed studies that involve biochemical and
molecular analyses.
2010-01-01T00:00:00ZUse of recombinant protein fragments from Mycoplasma mycoides subsp. Mycoides sc to jmprove Contagious bovine pleuropneumonia (CBPP) t cell And antibody based assaysNYANGAHU, Ondigo Bartholomewhttps://repository.maseno.ac.ke/handle/123456789/51912022-04-25T09:34:18Z2010-01-01T00:00:00ZUse of recombinant protein fragments from Mycoplasma mycoides subsp. Mycoides sc to jmprove Contagious bovine pleuropneumonia (CBPP) t cell And antibody based assays
NYANGAHU, Ondigo Bartholomew
Contagious bovine pleuropneumonia (CBPP), caused by the bacterium Mycoplasma mycoides
subsp. mycoides biotype Small Colony type (MmmSC), is a highly contagious respiratory disease
that causes significant losses of cattle in more than 26 countries of sub-Saharan Africa.
Development of reliable diagnostic tools is key to helping monitor disease 'prevalence and
incidence. This study screened selected recombinant MmmSC antigens for their potential in
antibody based diagnostics and their ability to activate memory T cells. Gene fragments from the
surface located MmmSC molecules were expressed in Escherichia coli expression systems and
the recombinant protein fragments purified for further usage: They were tested against ten sera
from. infected and uninfected cattle to evaluate their potential for improved CBPP diagnostic.
They were also tested for their ability to stimulate memory T lymphocytes from experimentally
MmmSC infected cattle. Peripheral blood mononuclear cells (PBMCs) from ten. cattle were.
stimulated with recombinant MmmSC antigens for 72 hours and Il-Ny secreticn was measured
using Bovigam kit {AgriQuality, Australia). The different responses elicited by the antigens were
compared using student t-test. The results showed that none of the recombinant fragments
induced IFNy higher than the cut- off value of (2:0.7). However, heat inactivated MmmSC lysate
induced IFNy secretion (P <0.05) but the recombinant fragments did not induce significant.
amounts of IFNy secretion (P > 0.05) when preinfection and post infection time points were .
compared. Also, none of the recombinant protein fragments was recognized by post infection.
sera. The results showed that antibody based diagnostics based on these particular recombinant
protein fragments is not feasible. The study concluded that the recombinant protein fragments
tested did not have strong T cell epitopes or T cells failed to migrate to circulation. Absence of
antibodies suggested lack of B cell epitopes in the structure of these recombinant fragments.
2010-01-01T00:00:00ZImpact of Insecticide-Treated Bednets and Indoor Residual Spraying on Host Selection by Anopheles Gambiae S.S., Anopheles Arabiensis and Anopheles Funestus in Western KenyaABONG'O, Bernard Onyangohttps://repository.maseno.ac.ke/handle/123456789/51122022-03-24T06:49:06Z2012-01-01T00:00:00ZImpact of Insecticide-Treated Bednets and Indoor Residual Spraying on Host Selection by Anopheles Gambiae S.S., Anopheles Arabiensis and Anopheles Funestus in Western Kenya
ABONG'O, Bernard Onyango
Malaria continues to be a global public health priority with unprecedented scale-up of
insecticide based interventions in the sub-tropics. The World Health Organization (WHO) has
approved vector control using insecticide. treated nets (lTNs) and indoor residual-insecticide
spraying (IRS) as the key malaria vector control strategies and has been adopted in most
countries in Africa. In Kenya, despite the increase in ITN coverage and the expansion of IRS
programs especially in western Kenya, mosquitoes continue to feed a~d, transmit malaria. One
question from this observation is whether the presence of these interventions have influenced
the host preferences for the local vectors or whether some species, due to their feeding habit
and feeding behavior, continue to proliferate and have gained dominance in this region. The
purpose of this study was to investigate host preference by three main malaria vectors (An.
gambiae s.s., An. arabiensis and An. Junestus) in the presence of different levels of vector
control interventions in western Kenya and to assess the accuracy of different mosquito
sampling methods aimed at collecting vectors from the immediate presence of the host in
estimating host selection for Anopheles vectors. The study was conducted in 4 districts;
Nyando, Rarieda, Teso and Bungoma selected based on vector composition and -intervention
type. Mosquito samples were collected indoors (by pyrethrum spray collection and CDC light
traps) and outdoors (by clay pots and CDC light traps) during the months of September to
December, 2010. The samples were identified morphologically and by polymerase chain
reaction (PCR), and all blood fed Anopheles samples were analyzed by sequencing followed by
a Basic Local Alignment Search Tool (BLAST) search in the GenBank database to determine
mosquito blood meal host. Results revealed no significant impact of intervention on selection
for human blood meal for IRS (p = 0.09), both IRS and ITN (p = 0.74) and ITN (p = 0.55).
The range of hosts fed on by Anopheles vectors 'in western Kenya included human (82.57%),
bovine (3.63%), goat (0.65%), rats (0.28%), wild birds (0.09%) and frogs (0.09%). An.
gambiae s.s. and An. Junestus displayed an almost exclusive selection for human blood meal
without a significant difference between the species (p = 0.31), while An. arabiensis fed on
both human and cattle but with significantly higher preference for cattle blood meal (p =
0.0002). From the collection methods, pyrethrum spray collection (PSC) results showed 93.2%
human and 6.08% cattle blood meal, light traps both indoor and outdoor had 97.1% human and
2.8% cattle blood meal while pots reported 100% human blood meal. Information generated
from this study is necessary for improvement of implementation of vector control. Despite
these interventions, the feeding behavior as measured by host selection was similar across all
houses, indicating that interventions present in those houses did not affect host selection
behavior. Two of the three malaria vector species (An. gambiae s.s and An. Junestus) displayed
strong anthropophilic trends while a third (An. arabiensisi fed on humans and cattle. Besides,
host selection was observed to be dependent on vector behavior and was unlikely to be
accurately estimated by mosquito sampling techniques aimed at collecting vectors from a
specific environment of the host. The extent of human-vector contact as depicted in this study
predicted continued risk of malaria infection and adequate measures are necessary to establish
vector feeding behavior, prevention and control. Pyrethrum spray collections appeared to be
the best tool in collection of fed and half gravid samples for blood meal analysis while at the
same time provided samples for the widest range of Anopheles hosts.
2012-01-01T00:00:00ZPrevalence and factors associated with immunological thyroid disease among thyroid disorder patients at Moi teaching and referral hospital (MTRH), western KenyaIDDAH, Maulid Alihttps://repository.maseno.ac.ke/handle/123456789/50382022-03-11T08:03:01Z2013-01-01T00:00:00ZPrevalence and factors associated with immunological thyroid disease among thyroid disorder patients at Moi teaching and referral hospital (MTRH), western Kenya
IDDAH, Maulid Ali
Autoimmune thyroiditis is an inflammatory or antireceptor autoimmune condition
characterized by reactivity to expressed self-thyroid antigens, and is one of the principal \ thyroid gland diseases. In Kenya, where the mode of treatment to thyroid' disorders is mainly
thyroidectomy, documentation of case patterns, prevalence and etiology is still very poor.
Therefore this study was done to determine the prevalence, histological patterns, and the
levels of thyroid hormones and autoantibodies in immunological thyroid disease patients at
Moi Teaching and Referral Hospital (MTRH) in western Kenya. This was a retrospective
study in which, samples and data from 388 patients who presented with thyroid pathologies
between 2008 and 2011, had thyroidectomy done, and samples taken for histological analysis
and diagnosis. Clinical data on thyroid hormones and histopathological diagnosis were
extracted from the patient's medical records. Data was analyzed using STAT A version SEII0
(College Station, Texas, USA). The results showed that the prevalence levels were; thyroiditis
24 (6.2%), thyroid carcinoma 18 (4.6%), thyroid adenoma 51 (13.1%), colloid goitre 286
(73.7%), thyroid cysts 8 (2.1%) and thyroid abscess 1 (0.3%). Immunological thyroid disease
was present in 175 (45%,95% CL: 40-50) subjects. The median thyroid stimulating hormone levels was TSH 1.8 (IQR: 0.9-2.9), T3 1.8 (IQR: 1.3-2.7) and T4 1.2 (IQR: 0.7-1.9). Thyroid
stimulating hormone (TSH) and triiodothyronine hormone (T3) levels for immunological
thyroid disease patients were higher (p=0.0232; 0.040, respectively), for those aged 30-39
years. Similarly, creatinine level for immunological thyroid disease patients, median: 58
(lQR: 50-67), were higher (p=0.039) for immunological thyroid disease patients. The
presence of the thyroid auto antibodies was significantly associated with the autoimmune
thyroid disease (p=O.OOI). The results showed that the prevalence of immunological thyroid
disease was higher (7.5%) than the earlier reported prevalence (2%) by other studies in Kenya
and that thyroid hormone levels (TSH) and triiodothyronine hormones (T3) significantly
contribute to the occurrence of immunological thyroid disease. This study has shown that the
hormonal, auto antibodies, biochemical and hematological profiles are altered in
immunological thyroid disease patients and hence these parameters can serve as a tool for diagnosing thyroid autoimmunity.
2013-01-01T00:00:00ZThe effect of plasmodium Falciparum parasitemia on the incidence of severe clinical events among HIV-1 exposed uninfected infants at Chulaimbo sub-district hospital in Kisumu county, Western KenyaOUMA, Edwin Odhiambohttps://repository.maseno.ac.ke/handle/123456789/12142019-01-28T06:35:46Z2018-01-01T00:00:00ZThe effect of plasmodium Falciparum parasitemia on the incidence of severe clinical events among HIV-1 exposed uninfected infants at Chulaimbo sub-district hospital in Kisumu county, Western Kenya
OUMA, Edwin Odhiambo
Human Immunodeficiency Virus (HIV) and malaria pose major public health problems due
to their high overlapping global geographic distribution and resultant high rates of coinfection.
Sub-Saharan Africa bears the greatest burden of HIV (67%) and malaria (86%)
infections. Malaria and HIV-1 are co-endemic in Kenya with more than 70% of the
population at risk of acquiring malaria and 5.6% of the population living with HIV. Kisumu
County in Western Kenya has a high prevalence of HIV (19.3%) and malaria (38%)
compared to other parts of the country. HIV and malaria modulate an infant’s immune
response in-utero. In co-infected individuals, HIV related immunosuppression may lead to
impaired control of parasitemia and increased risk of developing severe malaria. Moreover,
severe malaria is thought to strongly predispose infants to other infectious diseases. However,
the link between malarial infections and episodes of severe bacterial infections has not been
investigated in this region of Kisumu Kenya. This longitudinal prospective case-control study
examined the association between malarial infections and incidences of severe bacterial
infections in infants with and without in-utero exposure to HIV. HIV Exposed Uninfected
(HEU) refers to infants with in-utero exposure to HIV while HIV Unexposed Uninfected
(HUU) refers to infants without in-utero exposure to HIV. Both groups were HIV negative. A
total of 121 infants (HEU, n=63 and HUU, n=58) were recruited from the Chulaimbo subcounty
Hospital in Kisumu County. Blood was collected by a certified phlebotomist from
these infants at the ages of 6, 9, 12, 15, 18, 21, and 24 months. DNA was extracted from
whole blood samples and Plasmodium falciparum parasitemia determined by Real-time PCR.
The incidence of severe clinical infections was determined based on clinical data collected by
the study team at all scheduled follow-up visits and voluntary sick visits. Chi-Square tests
were used to compare the proportions of Pf positive samples in the HEU and the HUU infants
and to determine differences in proportions of severe clinical infections at individual time
points. Risk and odd ratios were used to determine the association between severe clinical
infections and malaria in HIV exposed and unexposed infants. Student t-test was used to
determine the difference in means at birth and 6-months of the anthropometric measures;
weight (birth, p=0.1449; 6-months, p=0.5325), height (birth, p=0.0236; 6-months, p=0.1831)
and head circumference (birth, p=0.6415; 6-months, p=0.1710) as well as the mean total
malaria diagnosis (p=0.0029) between the two exposure groups. HUU infants had a greater
proportion of “any-malaria” (p=0.0004) and total number of malaria episodes per infant
(p=0.0029) than HEU infants. Maternal HIV status was not related to the outcome of severe
clinical events (p=0.1295), with HEU infants having a lower but not statistically significant
risk and odds of bacterial related severe clinical events outcome, than their HUU
counterparts: diarrhea with severe dehydration (p=0.7817), severe pneumonia (p=0.3317) and
severe malaria (p=0.0954) as determined by Pearson’s Chi-square test between the two
exposure groups. Thus, the data suggests that the likelihood of severe clinical bacterial
infections is greater in HUU infants compared to HEU infants. The findings of this study may
be attributed to the positive effects of healthcare interventions such as Cotrimoxazole
prophylaxis treatment, insecticide treated bed net use, adherence to chemoprevention regimen
by HEU infants and exclusive breastfeeding. This calls for a keen focus on HUU infants who
are presumed to be healthier but seem to bear a greater burden of malaria infections and
severe-bacterial clinical events. These findings are important for healthcare provision to both
HEU and HUU infants residing in HIV and malaria co-endemic areas.
Masters' Thesis
2018-01-01T00:00:00ZEffects of Cotrimoxazole Withdrawal on Malaria Parasitemia Prevalence, Parasite Density and Multiplicity of Infection in Hiv-Infected Individuals With Immune Recovery Following Antiretroviral Treatment in Homabay CountyKWENDO, Ottichilo Ronaldhttps://repository.maseno.ac.ke/handle/123456789/11592021-04-15T06:57:05Z2016-01-01T00:00:00ZEffects of Cotrimoxazole Withdrawal on Malaria Parasitemia Prevalence, Parasite Density and Multiplicity of Infection in Hiv-Infected Individuals With Immune Recovery Following Antiretroviral Treatment in Homabay County
KWENDO, Ottichilo Ronald
Strategies to reduce HIV-related morbidity and mortality include scale up of Antiretroviral Therapy (ART) and provision of broad spectrum antibiotics. Cotrimoxazole (CTX) is a widely available low cost antibiotic recommended by WHO in settings with high infectious disease prevalence for treatment and prevention of opportunistic infections and malaria in all HIV-infected individuals. With immune reconstitution following ART, the risk of opportunistic infections greatly diminishes. Continuing CTX indefinitely raises concern about persistent antibiotic exposure, resistance and pill burden. The effect of CTX discontinuation on malaria remains undefined. This blinded Randomized Controlled Trial (RCT) investigated the effect of CTX discontinuation on malaria parasite prevalence, incidence, parasite density and Multiplicity of Infection (MOI) on HIV-infected adults with evidence of immune reconstitution. Five hundred participants were enrolled from Homabay County hospital and randomized into two study arms: discontinue CTX vs continue CTX. They were followed quarterly for 12 months and whenever they reported sick between February 2012 and September 2013. Blood was drawn from study participants at each visit and spotted on paper blots with subsequent DNA extraction. Malaria parasites were detected by qRT-PCR and MOI evaluated by nested PCR targeting MSP-1 (K1, MAD20 and RO33) and MSP-2 (FC27 and IC3D7) alleles. Chi-square was used to test differences in parasitemia prevalence over time between study arms. Where parasites were detected, parasite density values were log-transformed, and the difference between arms tested using generalized estimating equations. The frequency of mixed infections (MOI >1) was compared between the two study arms. Rates of parasitemia in the two study cohorts were calculated on the basis of person-time at risk. Among the 500 participants in the RCT, median CD4+ count was 595 cells/mm3 and the median ART duration was 4.5 years. Parasite prevalence at enrolment was: 4% for discontinue CTX arm and 6% for continue CTX arm. Within 3 months of CTX discontinuation, parasitemia prevalence increased steadily in the discontinue CTX arm during the year to >5-fold: 4% (11/248) at M3, 8% (21/249) at M6, 14% (33/244) at M9 and 22% (54/245) at M12. In comparison, the continue CTX arm had parasitemia prevalence of <1% (1/248) at M3, 2% (5/247) at M6, 2% (4/245) at M9 and 4% (10/245) at M12 (P < 0.0034). Post enrollment, discontinue CTX arm had 90 new infections compared to 23 in the continue CTX arm. Parasitemia incidence was 42.0 in discontinue CTX arm versus 9.9 per 100 person years in continue CTX arm; with an incident rate ratio of 4.3 (95% CI: 0.14-0.37; p<0.001). Among follow-up visits where parasites were detected, the discontinue CTX arm had a significantly higher mean parasite density (log10) than the continue CTX arm (4.42 parasites/mL vs. 3.13 parasites/mL, p < 0.001). Post enrolment, mixed infections (MOI >1) were only present in the STOP-CTX arm. Results from this study indict despite immune reconstitution following ART provision and use of ITNs. Discontinuation of CTX prophylaxis in individuals with HIV results in increased parasite prevalence, incidence, parasite density and MOI overtime, in malaria endemic regions. The increased malaria incidence seen in those who discontinue prophylaxis, is not due to a short-lived rebound effect following withdrawal of CTX but continues for a longer period. Therefore stopping CTX prophylaxis may not be recommended in the context of malaria in resource-limited settings.
2016-01-01T00:00:00Z