Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-7 (of 7 Records) |
Query Trace: Abudho B[original query] |
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Anti-schistosome responses after four annual treatments
Ndombi EM , Abudho B , Kittur N , Carter JM , Korir H , Riner DK , Ochanda H , Lee YM , Secor WE , Karanja DM , Colley DG . Parasite Immunol 2018 40 (6) e12530 AIM: This study evaluated potential changes in anti-schistosome immune responses in children from schools that received four rounds of annual mass drug administration (MDA) of praziquantel (PZQ). METHODS: In a repeated cross-sectional study design, 210 schistosome egg-positive children were recruited at baseline from schools in western Kenya (baseline group). Another 251 children of the same age range were recruited from the same schools and diagnosed for schistosome infection by microscopy (post-MDA group). In-vitro schistosome-specific cytokines and plasma antibody levels were measured by ELISA and compared between the two groups of children. RESULTS: Schistosome soluble egg antigen (SEA) and soluble worm antigen preparation (SWAP) stimulated higher IL-5 production by egg-negative children in the post-MDA group compared to the baseline group. Similarly, anti-SEA IgE levels were higher in egg negative children in the post-MDA group compared to the baseline group. Anti-SEA and anti-SWAP IgG4 levels were lower in egg negative children in the post-MDA group compared to baseline. This resulted in higher anti-SEA IgE/IgG4 ratios for children in the post-MDA group compared to baseline. CONCLUSION: These post-MDA immunological changes are compatible with the current paradigm that treatment shifts immune responses to higher anti-schistosome IgE:IgG4 ratios in parallel with a potential increase in resistance to reinfection. This article is protected by copyright. All rights reserved. |
Impact of four years of annual mass drug administration on prevalence and intensity of schistosomiasis among primary and high school children in Western Kenya: A repeated cross-sectional study
Abudho BO , Ndombi EM , Guya B , Carter JM , Riner DK , Kittur N , Karanja DMS , Secor WE , Colley DG . Am J Trop Med Hyg 2018 98 (5) 1397-1402 Schistosomiasis remains a major public health problem in Kenya. The World Health Organization recommends preventive chemotherapy with praziquantel (PZQ) to control morbidity due to schistosomiasis. Morbidity is considered linked to intensity of infection, which along with prevalence is used to determine the frequency of mass drug administration (MDA) to school-age children. We determined the impact of annual school-based MDA on children across all primary and high school years using a repeated cross-sectional study design in five schools near Lake Victoria in western Kenya, an area endemic for Schistosoma mansoni. At baseline and for the following four consecutive years, between 897 and 1,440 school children in Grades 1-12 were enrolled and evaluated by Kato-Katz for S. mansoni and soil-transmitted helminths (STH), followed by annual MDA with PZQ and albendazole. Four annual rounds of MDA with PZQ were associated with reduced S. mansoni prevalence in all school children (44.7-14.0%; P < 0.001) and mean intensity of infection by 91% (90.4 to 8.1 eggs per gram [epg] of stool; P < 0.001). Prevalence of high-intensity infection (>/= 400 epg) decreased from 6.8% at baseline to 0.3% by the end of the study. Soil-transmitted helminth infections, already low at baseline, also decreased significantly over the years. In this high prevalence area, annual school-based MDA with high coverage across all Grades (1-12) resulted in rapid and progressive declines in overall prevalence and intensity of infection. This decrease was dramatic in regard to heavy infections in older school-attending children. |
Cluster randomized trial comparing school-based mass drug administration schedules in areas of western Kenya with moderate initial prevalence of Schistosoma mansoni infections
Karanja DMS , Awino EK , Wiegand RE , Okoth E , Abudho BO , Mwinzi PNM , Montgomery SP , Secor WE . PLoS Negl Trop Dis 2017 11 (10) e0006033 BACKGROUND: Mass drug administration (MDA) using praziquantel is the WHO-recommended approach for control of schistosomiasis. However, few studies have compared the impact of different schedules of MDA on the resultant infection levels. We wished to evaluate whether annual MDA was more effective than less frequent treatments for reducing community-level prevalence and intensity of Schistosoma mansoni infections. METHODS: We performed a cluster randomized trial (ISRCTN 14849830) of 3 different MDA frequencies over a 5 year period in 75 villages with moderate (10%-24%) initial prevalence of S. mansoni in school children in western Kenya. Praziquantel was distributed by school teachers to students either annually, the first 2 years, or every other year over a 4 year period. Prevalence and intensity of infection were measured by stool examination in 9-12 year old students using the Kato-Katz method at baseline, each treatment year, and for the final evaluation at year 5. S. mansoni prevalence and intensity were also measured in first year students at baseline and year 5. RESULTS: Twenty-five schools were randomly assigned to each arm. S. mansoni prevalence and infection intensity in 9-12 year old students significantly decreased within each arm from baseline to year 5 but there were no differences between arms. There were no differences in infection levels in first year students either within or between arms. CONCLUSIONS: Strategies employing 2 or 4 rounds of MDA had a similar impact in schools with moderate initial prevalence, suggesting that schistosomiasis control can be sustained by school-based MDA, even if provided only every other year. |
Predictive value of school-aged children's schistosomiasis prevalence and egg intensity for other age groups in Western Kenya
Mwinzi PN , Muchiri G , Wiegand RE , Omedo M , Abudho B , Karanja DM , Montgomery SP , Secor WE . Am J Trop Med Hyg 2015 93 (6) 1311-7 World Health Organization recommendations for the timing and target population for mass drug administration (MDA) for schistosomiasis are based on the prevalence of infection in school children within a given community. In a large study comparing MDA approaches for Schistosoma mansoni control, we evaluated whether prevalence of infection and egg burdens in 9- to 12-year-old students reflected infection levels in young children and adults in the same community. Cross-sectional surveys of preadolescents (9-12 years old) were compared with those of first year students (5-8 years old) in 225 villages and adults (20-55 years old) in 150 villages along the Kenyan shores of Lake Victoria. Village schistosomiasis prevalence and intensity levels in preadolescents strongly correlated (P < 0.0001) with prevalence and infection intensity for other age groups in the community. Our findings suggest that S. mansoni prevalence and intensity among 9- to 12-year-olds are valid for community sampling purposes in mapping for MDAs. |
Assessment of quality of life as a tool for measuring morbidity due to Schistosoma mansoni infection and the impact of treatment
Won KY , Abudho B , Blackstock A , Montgomery SP , Kennedy ED , Person B , Mwinzi PN , Ochola EA , Foo KT , Hightower AW , Karanja DM , Secor WE . Am J Trop Med Hyg 2013 90 (2) 322-8 Recently, health measurements have broadened to include the assessment of quality of life (QOL). This study was conducted to assess whether the short form of the World Health Organization (WHO) QOL questionnaire (WHOQOL-BREF) was an effective tool for measuring morbidity due to Schistosoma mansoni infection and whether it could detect an impact of treatment with praziquantel. A total of 724 adults 18-85 years of age were enrolled. At baseline, S. mansoni prevalence was 73.2% by stool examination and 75.4% by circulating cathodic antigen, and there was no association between infection status and WHOQOL-BREF scores. Six months after treatment, S. mansoni prevalence was lower and the proportion of persons with higher WHOQOL-BREF scores significantly increased among persons who were infected at baseline. However, a similar increase was observed in persons infected at baseline. In areas of high prevalence, the WHOQOL-BREF may not be able to detect the benefits of schistosomiasis control programs. |
Schistosomiasis among young children in Usoma, Kenya
Verani JR , Abudho B , Montgomery SP , Mwinzi PN , Shane HL , Butler SE , Karanja DM , Secor WE . Am J Trop Med Hyg 2011 84 (5) 787-91 Although schistosomiasis burden is greatest among school-age children (SAC) (6-15 years of age), infection among preschool-age children (PSAC) (1-5 years), may be underestimated in endemic areas. We conducted a cross-sectional study evaluating Schistosoma mansoni infection among children 1-15 years of age in a highly endemic community in Kenya. Diagnostic tests included stool exam (Kato/Katz technique), serum testing for schistosome-specific antibodies, and urine testing for circulating cathodic antigen (CCA). Overall, 268 SAC and 216 PSAC were enrolled; prevalence increased with age, with 14% of 1 year olds and more than 90% of children > 10 years of age infected. Stool exam was more sensitive among SAC than PSAC, but performance was similar after adjusting for infection intensity (based on CCA). Schistosomiasis poses a threat to PSAC in endemic areas, and stool exam may underestimate the prevalence of infection. Control programs in such areas should consider PSAC in addition to SAC. |
Evaluation of urine CCA assays for detection of Schistosoma mansoni infection in western Kenya
Shane HL , Verani JR , Abudho B , Montgomery SP , Blackstock AJ , Mwinzi PN , Butler SE , Karanja DM , Secor WE . PLoS Negl Trop Dis 2011 5 (1) e951 Although accurate assessment of the prevalence of Schistosoma mansoni is important for the design and evaluation of control programs, the most widely used tools for diagnosis are limited by suboptimal sensitivity, slow turn-around-time, or inability to distinguish current from former infections. Recently, two tests that detect circulating cathodic antigen (CCA) in urine of patients with schistosomiasis became commercially available. As part of a larger study on schistosomiasis prevalence in young children, we evaluated the performance and diagnostic accuracy of these tests-the carbon test strip designed for use in the laboratory and the cassette format test intended for field use. In comparison to 6 Kato-Katz exams, the carbon and cassette CCA tests had sensitivities of 88.4% and 94.2% and specificities of 70.9% and 59.4%, respectively. However, because of the known limitations of the Kato-Katz assay, we also utilized latent class analysis (LCA) incorporating the CCA, Kato-Katz, and schistosome-specific antibody results to determine their sensitivities and specificities. The laboratory-based CCA test had a sensitivity of 91.7% and a specificity of 89.4% by LCA while the cassette test had a sensitivity of 96.3% and a specificity of 74.7%. The intensity of the reaction in both urine CCA tests reflected stool egg burden and their performance was not affected by the presence of soil transmitted helminth infections. Our results suggest that urine-based assays for CCA may be valuable in screening for S. mansoni infections. |
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