209 research outputs found
ANALYSIS ON THE BURDEN OF HELMINTHS-Plasmodium falciparum POLYPARASITISM, EFFECT ON ANAEMIA AND THE ROLE OF INTEGRATED SCHOOL BASED PARASITE CONTROL AND HEALTH EDUCATION IN ZIMBABWE. BY
No full textii DEDICATION I dedicate this thesis to my dearest family, my wife and sons, who allowed me to spend time away from them whilst doing field work and come home late during the period of this thesis
Cytokine responses to <it>Schistosoma haematobium </it>in a Zimbabwean population: contrasting profiles for IFN-γ, IL-4, IL-5 and IL-10 with age
No full textAbstract Background The rate of development of parasite-specific immune responses can be studied by following their age profiles in exposed and infected hosts. This study determined the cytokine-age profiles of Zimbabweans resident in a Schistosoma haematobium endemic area and further investigated the relationship between the cytokine responses and infection intensity. Methods Schistosome adult worm antigen-specific IFN-γ, IL-4, IL-5 and IL-10 cytokine responses elicited from whole blood cultures were studied in 190 Zimbabweans exposed to S. haematobium infection (aged 6 to 40 years old). The cytokines were measured using capture ELISAs and the data thus obtained together with S. haematobium egg count data from urine assays were analysed using a combination of parametric and nonparametric statistical approaches. Results Age profiles of schistosome infection in the study population showed that infection rose to peak in childhood (11–12 years) followed by a sharp decline in infection intensity while prevalence fell more gradually. Mean infection intensity was 37 eggs/10 ml urine (SE 6.19 eggs/10 ml urine) while infection prevalence was 54.7%. Measurements of parasite-specific cytokine responses showed that IL-4, IL-5 and IL-10 but not IFN-γ followed distinct age-profiles. Parasite-specific IL-10 production developed early, peaking in the youngest age group and declining thereafter; while IL-4 and IL-5 responses were slower to develop with a later peak. High IL-10 producers were likely to be egg positive with IL-10 production increasing with increasing infection intensity. Furthermore people producing high levels of IL-10 produced little or no IL-5, suggesting that IL-10 may be involved in the regulation of IL-5 levels. IL-4 and IFN-γ did not show a significant relationship with infection status or intensity and were positively associated with each other. Conclusion Taken together, these results show that the IL-10 responses develop early compared to the IL-5 response and may be down-modulating immunopathological responses that occur during the early phase of infection. The results further support current suggestions that the Th1/Th2 dichotomy does not sufficiently explain susceptibility or resistance to schistosome infection.</p
ANALYSIS ON THE BURDEN OF HELMINTHS-Plasmodium falciparum POLYPARASITISM, EFFECT ON ANAEMIA AND THE ROLE OF INTEGRATED SCHOOL BASED PARASITE CONTROL AND HEALTH EDUCATION IN ZIMBABWE.
No full textIntroduction: Globally, 207 million; 2 billion and 243 million people are infected with schistosomiasis (SCH), soil transmitted helminths (STH) and Plasmodium falciparum (P.f) respectively. Many of the affected people are primary school age children. Clinical outcomes of these parasitic infections include anaemia, impaired cognition and malnutrition. Although these parasites have different mechanisms through which they cause anaemia, data is scarce on the extent of helminths –Plasmodium polyparasitism and their effect on anaemia. We determined the extent of helminths-Plasmodium co-infections, their effect on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anaemia among primary schoolchildren in rural and farming areas in Zimbabwe.
Overall objective: To determine the prevalence of single and helminths–Plasmodium co-infections among primary schoolchildren living in rural and commercial farming areas, the effect of co-infections on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anemia.
Settings: The study was conducted in Nyamaropa rural area, Shamva districts and Burma Valley commercial farming areas in Mutare district, Zimbabwe.
Study design: The study was a longitudinal intervention trial, which involved treatment of infected children at baseline, 6, 12 and 33 months follow up surveys.
Methodology: Enrolled participants were screened for anaemia; schistosomiasis; STHs and P. falciparum (P.f) using the Hemocue machine, urine filtration technique, a combination of the Kato Katz and formal ether concentration techniques and Giemsa staining respectively at each survey.
Results: Helminths- Plasmodium co-infections were heterogeneously distributed and were observed in the commercial farming area only. Overall, the prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, that of S. mansoni was 12.4% and 22.7%.. P. f, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Hookworm and S. mansoni infections were associated with P. f (P < 0.001, OR = 2.48, 95% CI: 1.56-3.93 and P = 0.005, OR = 1.85, 95% CI: 1.20-2.87). Of the 475 children screened for all parasites and anaemia, received combined treatment at baseline and successfully followed up to 33 months post treatment survey, 11.2%; 10.9%; 1.3% and 5.1% had SCH + STHs; SCH + P. f; STH + P. f; SCH+ STH + P. f co-infections respectively at baseline. These co-infections declined to 6.3%; 2.1%; 0.4; 1.1%, respectively at 33 months follow up survey. Overall, anaemia declined from 45.7% at baseline to 15.4% at 33 months follow up survey after treatment intervention, p < 0.001. School health education increased the knowledge of grade 3 children about causes of helminths and P. falciparum
Conclusions: There is heterogeneity in the distribution of helminths –Plasmodium co-infections in diverse communities. Co-infections have a multiplicative effect on anaemia. Biannual combined school based treatment intervention reduces the prevalence of helminths-Plasmodium co-infections and anaemia. Determination of the extent of helminths –Plasmodium co-infection should be prioritized in planning allocation of limited resources for control. The Government of Zimbabwe nationalized this PhD work. The work also contributed towards the national policy formulation for the control of schistosomiasis, STH and other neglected tropical diseases in Zimbabwe.WHO/TDR & Essential National Health Research funding (Health and Child Welfare
ANALYSIS ON THE BURDEN OF HELMINTHS-Plasmodium falciparum POLYPARASITISM, EFFECT ON ANAEMIA AND THE ROLE OF INTEGRATED SCHOOL BASED PARASITE CONTROL AND HEALTH EDUCATION IN ZIMBABWE.
No full textIntroduction: Globally, 207 million; 2 billion and 243 million people are infected with schistosomiasis (SCH), soil transmitted helminths (STH) and Plasmodium falciparum (P.f) respectively. Many of the affected people are primary school age children. Clinical outcomes of these parasitic infections include anaemia, impaired cognition and malnutrition. Although these parasites have different mechanisms through which they cause anaemia, data is scarce on the extent of helminths –Plasmodium polyparasitism and their effect on anaemia. We determined the extent of helminths-Plasmodium co-infections, their effect on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anaemia among primary schoolchildren in rural and farming areas in Zimbabwe.
Overall objective: To determine the prevalence of single and helminths–Plasmodium co-infections among primary schoolchildren living in rural and commercial farming areas, the effect of co-infections on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anemia.
Settings: The study was conducted in Nyamaropa rural area, Shamva districts and Burma Valley commercial farming areas in Mutare district, Zimbabwe.
Study design: The study was a longitudinal intervention trial, which involved treatment of infected children at baseline, 6, 12 and 33 months follow up surveys.
Methodology: Enrolled participants were screened for anaemia; schistosomiasis; STHs and P. falciparum (P.f) using the Hemocue machine, urine filtration technique, a combination of the Kato Katz and formal ether concentration techniques and Giemsa staining respectively at each survey.
Results: Helminths- Plasmodium co-infections were heterogeneously distributed and were observed in the commercial farming area only. Overall, the prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, that of S. mansoni was 12.4% and 22.7%.. P. f, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Hookworm and S. mansoni infections were associated with P. f (P < 0.001, OR = 2.48, 95% CI: 1.56-3.93 and P = 0.005, OR = 1.85, 95% CI: 1.20-2.87). Of the 475 children screened for all parasites and anaemia, received combined treatment at baseline and successfully followed up to 33 months post treatment survey, 11.2%; 10.9%; 1.3% and 5.1% had SCH + STHs; SCH + P. f; STH + P. f; SCH+ STH + P. f co-infections respectively at baseline. These co-infections declined to 6.3%; 2.1%; 0.4; 1.1%, respectively at 33 months follow up survey. Overall, anaemia declined from 45.7% at baseline to 15.4% at 33 months follow up survey after treatment intervention, p < 0.001. School health education increased the knowledge of grade 3 children about causes of helminths and P. falciparum
Conclusions: There is heterogeneity in the distribution of helminths –Plasmodium co-infections in diverse communities. Co-infections have a multiplicative effect on anaemia. Biannual combined school based treatment intervention reduces the prevalence of helminths-Plasmodium co-infections and anaemia. Determination of the extent of helminths –Plasmodium co-infection should be prioritized in planning allocation of limited resources for control. The Government of Zimbabwe nationalized this PhD work. The work also contributed towards the national policy formulation for the control of schistosomiasis, STH and other neglected tropical diseases in Zimbabwe.WHO/TDR & Essential National Health Research funding (Health and Child Welfare
Knowledge attitudes and practices of grade three primary school children in relation to schistosomiasis, soil transmitted helminthiasis and malaria in Zimbabwe
No full textHelminth infection rates in grade three children are used as proxy indicators of community infection status and to guide treatment strategies in endemic areas. However knowledge, attitudes and practices (KAP) of this target age group (8-10 years) in relation to schistosomiasis, soil transmitted helminthiasis (STHs) and malaria is not known at a time when integrated plasmodium - helminth control strategies are being advocated. This study sought to assess KAP of grade 3 children in relation to schistosomiasis, STHs and malaria in order to establish an effective school based health education for disease transmission control. Grade 3 children (n = 172) attending four randomly selected primary schools (one in rural and 3 in the commercial farming areas) in Zimbabwe were interviewed using a pre-tested interviewer administered questionnaire. The urine filtration technique was used to determine S. haematobium infection status. Infection with S. mansoni and STHs was determined using a combination of results from the Kato Katz and formol ether concentration techniques. P. falciparum was diagnosed by examination of Giemsa stained thick blood smears. It was observed that 32.0%, 19.2% and 4.1% of the respondents had correct knowledge about the causes of schistosomiasis, malaria and STHs, respectively, whilst 22.1%, 19.2% and 5.8% knew correct measures to control schistosomiasis, malaria and STHs. Sixty-two percent and 44.8% did not use soap to wash hands after toilet and before eating food respectively, whilst 33.1% never wore shoes. There were no functional water points and soap for hand washing after toilet at all schools. There was a high prevalence distribution of all parasites investigated in this study at Msapa primary school - S. haematobium (77.8%), S. mansoni (33.3%) hookworms (29.6%) and P.falciparum (48.1%). Reports that participant had suffered from schistosomiasis and malaria before were significantpredictors of these diseases (p = 0.001 and p = 0.042, respectively). Report that participant had blood in urine on the day of examination was a significant predictor of schistosomiasis (p = 0.045). There is a critical need for targeting health messages through schools in order to reach the most susceptible schoolchildren. This will empower the schoolchildren with the basic knowledge and skills ultimatel
Efficacy of integrated school based de-worming and prompt malaria treatment on helminths -Plasmodium falciparum co-infections: A 33 months follow up study
No full textThe geographical congruency in distribution of helminths and Plasmodium falciparum makes
polyparasitism a common phenomenon in Sub Saharan Africa. The devastating effects of helminths-Plasmodium co-infections on primary school health have raised global interest for integrated control. However little is known on the feasibility, timing and efficacy of integrated helminths-Plasmodium control strategies. A study was conducted in Zimbabwe to evaluate the efficacy of repeated combined school based antihelminthic and prompt malaria treatment. A cohort of primary schoolchildren (5-17 years) received combined Praziquantel, albendazole treatment at baseline, and again during 6, 12 and 33 months follow up surveys and sustained prompt malaria treatment. Sustained prompt malaria treatment was carried out throughout the study period. Children’s infection status with helminths, Plasmodium and helminths-Plasmodium co-infections was determined by parasitological examinations at baseline and at each treatment point. The prevalence of S. haematobium, S. mansoni, STH, malaria, helminths-Plasmodium co-infections and helminths infection intensities before and after treatment were analysed. Longitudinal data showed that two rounds of combined Praziquantel and albendazole treatment for schistosomiasis and STHs at 6 monthly intervals and sustained prompt malaria treatment significantly reduced the overall prevalence of S. haematobium, S. mansoni, hookworms and P. falciparum infection in primary schoolchildren by 73.5%, 70.8%, 67.3% and 58.8% respectively (p < 0.001, p < 0.001, p < 0.001, p < 0.001 respectively). More
importantly, the prevalence of STH + schistosomes, P. f + schistosomes, and P. f + STHs + schistosomes coinfections were reduced by 68.0%, 84.2%, and 90.7%, respectively. The absence of anti-helminthic treatment between the 12 mth and 33 mth follow-up surveys resulted in the sharp increase in STHs + schistosomes coinfection from 3.3% at 12 months follow up survey to 10.7%, slightly more than the baseline level (10.3%) while other co-infection combinations remained significantly low. The overall prevalence of heavy S. haematobium, S. mansoni and hookworms infection intensities were significantly reduced from: 17.9-22.4% to 2.6-5.1%, 1.6-3.3% to
0.0% and 0.0-0.7% to 0.0% respectively. Biannual Integrated school based antihelminthic and sustained prompt malaria treatment has a potential to reduce the burden of helminths-plasmodium co-infections in primary school children. In areas of stable malaria transmission, active case finding is recommended to track and treat asymptomatic malaria cases as these may sustain transmission in the community.,The UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases Grant A60125, ENHR-Ministry of Health and child Welfare, Harare, Zimbabwe, Fogarty Grant for field work to NK and DS. International Foundation for Science Grantee: W/4321-1 to TM
ANALYSIS ON THE BURDEN OF HELMINTHS-Plasmodium falciparum POLYPARASITISM, EFFECT ON ANAEMIA AND THE ROLE OF INTEGRATED SCHOOL BASED PARASITE CONTROL AND HEALTH EDUCATION IN ZIMBABWE.
No full textIntroduction: Globally, 207 million; 2 billion and 243 million people are infected with schistosomiasis (SCH), soil transmitted helminths (STH) and Plasmodium falciparum (P.f) respectively. Many of the affected people are primary school age children. Clinical outcomes of these parasitic infections include anaemia, impaired cognition and malnutrition. Although these parasites have different mechanisms through which they cause anaemia, data is scarce on the extent of helminths –Plasmodium polyparasitism and their effect on anaemia. We determined the extent of helminths-Plasmodium co-infections, their effect on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anaemia among primary schoolchildren in rural and farming areas in Zimbabwe.
Overall objective: To determine the prevalence of single and helminths–Plasmodium co-infections among primary schoolchildren living in rural and commercial farming areas, the effect of co-infections on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anemia.
Settings: The study was conducted in Nyamaropa rural area, Shamva districts and Burma Valley commercial farming areas in Mutare district, Zimbabwe.
Study design: The study was a longitudinal intervention trial, which involved treatment of infected children at baseline, 6, 12 and 33 months follow up surveys.
Methodology: Enrolled participants were screened for anaemia; schistosomiasis; STHs and P. falciparum (P.f) using the Hemocue machine, urine filtration technique, a combination of the Kato Katz and formal ether concentration techniques and Giemsa staining respectively at each survey.
Results: Helminths- Plasmodium co-infections were heterogeneously distributed and were observed in the commercial farming area only. Overall, the prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, that of S. mansoni was 12.4% and 22.7%.. P. f, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Hookworm and S. mansoni infections were associated with P. f (P < 0.001, OR = 2.48, 95% CI: 1.56-3.93 and P = 0.005, OR = 1.85, 95% CI: 1.20-2.87). Of the 475 children screened for all parasites and anaemia, received combined treatment at baseline and successfully followed up to 33 months post treatment survey, 11.2%; 10.9%; 1.3% and 5.1% had SCH + STHs; SCH + P. f; STH + P. f; SCH+ STH + P. f co-infections respectively at baseline. These co-infections declined to 6.3%; 2.1%; 0.4; 1.1%, respectively at 33 months follow up survey. Overall, anaemia declined from 45.7% at baseline to 15.4% at 33 months follow up survey after treatment intervention, p < 0.001. School health education increased the knowledge of grade 3 children about causes of helminths and P. falciparum
Conclusions: There is heterogeneity in the distribution of helminths –Plasmodium co-infections in diverse communities. Co-infections have a multiplicative effect on anaemia. Biannual combined school based treatment intervention reduces the prevalence of helminths-Plasmodium co-infections and anaemia. Determination of the extent of helminths –Plasmodium co-infection should be prioritized in planning allocation of limited resources for control. The Government of Zimbabwe nationalized this PhD work. The work also contributed towards the national policy formulation for the control of schistosomiasis, STH and other neglected tropical diseases in Zimbabwe
Analysis on the Burden of Helminths-Plasmodium Falciparum Polyparasitism, Effect on Anaemia and the Role of Integrated School Based Parasite Control and Health Education in Zimbabwe
No full textIntroduction: Globally, 207 million; 2 billion and 243 million people are infected with schistosomiasis (SCH), soil transmitted helminths (STH) and Plasmodium falciparum (P.f) respectively. Many of the affected people are primary school age children. Clinical outcomes of these parasitic infections include anaemia, impaired cognition and malnutrition. Although these parasites have different mechanisms through which they cause anaemia, data is scarce on the extent of helminths –Plasmodium polyparasitism and their effect on anaemia. We determined the extent of helminths-Plasmodium co-infections, their effect on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anaemia among primary schoolchildren in rural and farming areas in Zimbabwe.
Overall objective: To determine the prevalence of single and helminths–Plasmodium co-infections among primary schoolchildren living in rural and commercial farming areas, the effect of co-infections on anaemia and the efficacy of combined school based treatment intervention on prevalence of co-infections and anemia.
Settings: The study was conducted in Nyamaropa rural area, Shamva districts and Burma Valley commercial farming areas in Mutare district, Zimbabwe.
Study design: The study was a longitudinal intervention trial, which involved treatment of infected children at baseline, 6, 12 and 33 months follow up surveys.
Methodology: Enrolled participants were screened for anaemia; schistosomiasis; STHs and P. falciparum (P.f) using the Hemocue machine, urine filtration technique, a combination of the Kato Katz and formal ether concentration techniques and Giemsa staining respectively at each survey.
Results: Helminths- Plasmodium co-infections were heterogeneously distributed and were observed in the commercial farming area only. Overall, the prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, that of S. mansoni was 12.4% and 22.7%.. P. f, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Hookworm and S. mansoni infections were associated with P. f (P < 0.001, OR = 2.48, 95% CI: 1.56-3.93 and P = 0.005, OR = 1.85, 95% CI: 1.20-2.87). Of the 475 children screened for all parasites and anaemia, received combined treatment at baseline and successfully followed up to 33 months post treatment survey, 11.2%; 10.9%; 1.3% and 5.1% had SCH + STHs; SCH + P. f; STH + P. f; SCH+ STH + P. f co-infections respectively at baseline. These co-infections declined to 6.3%; 2.1%; 0.4; 1.1%, respectively at 33 months follow up survey. Overall, anaemia declined from 45.7% at baseline to 15.4% at 33 months follow up survey after treatment intervention, p < 0.001. School health education increased the knowledge of grade 3 children about causes of helminths and P. falciparum
Conclusions: There is heterogeneity in the distribution of helminths –Plasmodium co-infections in diverse communities. Co-infections have a multiplicative effect on anaemia. Biannual combined school based treatment intervention reduces the prevalence of helminths-Plasmodium co-infections and anaemia. Determination of the extent of helminths –Plasmodium co-infection should be prioritized in planning allocation of limited resources for control. The Government of Zimbabwe nationalized this PhD work. The work also contributed towards the national policy formulation for the control of schistosomiasis, STH and other neglected tropical diseases in Zimbabwe
Integrated analysis of innate, Th1, Th2, Th17, and regulatory cytokines identifies changes in immune polarisation following treatment of human schistosomiasis.
No full textBACKGROUND: Schistosomiasis elicits cross-regulatory immune responses, but it is unclear how antihelminthic treatment affects this balance. This study integrates data on 13 cytokines elicited by 3 schistosome to examine how praziquantel treatment alters immune polarization and whether post-treatment cytokine profiles influence reinfection status. METHODS: Venous blood from 72 Schistosoma haematobium-exposed participants was cultured with schistosome egg, adult worm, and cercaria antigens pre- and 6 weeks post-praziquantel treatment. Innate inflammatory (tumor necrosis factor α [TNF-α], interleukin(IL-)-6, IL-8), Th1 (interferon γ [IFN-γ], IL-2, IL-12p70), Th2 (IL-4, IL-5, IL-13), Th17 (IL-17A, IL-21, IL-23p19), and regulatory (IL-10) cytokines were quantified via enzyme-linked immunosorbent assay. Cytokine data was integrated using nonmetric multidimensional scaling and factor analysis. RESULTS: Egg-specific cytokine phenotypes became more proinflammatory post-treatment due to increased TNF-α, IL-6, IL-8, IFN-γ, IL-12p70, and IL-23 levels. Post-treatment cercariae-specific responses were also more proinflammatory reflecting elevated IL-8. In contrast, post-treatment adult worm-specific responses were less inflammatory, reflecting lower post-treatment IL-6. A combination of egg-induced IL-6, IL-12p70, IL-21, and IL-23 and adult worm-induced IL-5 and IL-21 post-treatment was associated with reduced reinfection risk 18 months later. CONCLUSIONS: Praziquantel treatment markedly alters polarization of schistosome-specific cytokine responses, and these changes, particularly in response to egg-stage parasites, may promote resistance to reinfection
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