Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-16 (of 16 Records) |
Query Trace: Mwinzi PN[original query] |
---|
Gaining and sustaining schistosomiasis control: study protocol and baseline data prior to different treatment strategies in five African countries
Ezeamama AE , He CL , Shen Y , Yin XP , Binder SC , Campbell CH Jr , Rathbun S , Whalen CC , N'Goran EK , Utzinger J , Olsen A , Magnussen P , Kinung'hi S , Fenwick A , Phillips A , Ferro J , Karanja DM , Mwinzi PN , Montgomery S , Secor WE , Hamidou A , Garba A , King CH , Colley DG . BMC Infect Dis 2016 16 (1) 229 BACKGROUND: The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in 2008 to answer strategic questions about schistosomiasis control. For programme managers, a high-priority question is: what are the most cost-effective strategies for delivering preventive chemotherapy (PCT) with praziquantel (PZQ)? This paper describes the process SCORE used to transform this question into a harmonized research protocol, the study design for answering this question, the village eligibility assessments and data resulting from the first year of the study. METHODS: Beginning in 2009, SCORE held a series of meetings to specify empirical questions and design studies related to different schedules of PCT for schistosomiasis control in communities with high (gaining control studies) and moderate (sustaining control studies) prevalence of Schistosoma infection among school-aged children. Seven studies are currently being implemented in five African countries. During the first year, villages were screened for eligibility, and data were collected on prevalence and intensity of infection prior to randomisation and the implementation of different schemes of PZQ intervention strategies. RESULTS: These studies of different treatment schedules with PZQ will provide the most comprehensive data thus far on the optimal frequency and continuity of PCT for schistosomiasis infection and morbidity control. CONCLUSIONS: We expect that the study outcomes will provide data for decision-making for country programme managers and a rich resource of information to the schistosomiasis research community. TRIAL REGISTRATION: The trials are registered at International Standard Randomised Controlled Trial registry (identifiers: ISRCTN99401114 , ISRCTN14849830 , ISRCTN16755535 , ISRCTN14117624 , ISRCTN95819193 and ISRCTN32045736 ). |
Impact of two rounds of praziquantel mass drug administration on Schistosoma mansoni infection prevalence and intensity: a comparison between community wide treatment and school based treatment in western Kenya
Onkanga IO , Mwinzi PN , Muchiri G , Andiego K , Omedo M , Karanja DM , Wiegand RE , Secor WE , Montgomery SP . Int J Parasitol 2016 46 (7) 439-45 This study compared the effectiveness of the community-wide treatment and school-based treatment approaches in the control of Schistosoma mansoni infections in villages with 25% prevalence in western Kenya. Stool samples from first year students, 9-12year olds and adults (20-55years) were analyzed by the Kato-Katz technique for S. mansoni eggs. After two rounds of treatment, S. mansoni prevalence and intensity levels significantly declined in both treatment approaches. Prevalence comparisons between the two approaches did not show any significant differences following treatment. However, infection intensity levels in the 9-12year old school-attending pupils were significantly higher in the community-wide treatment arm than in the school-based treatment arm. Nevertheless, significant reductions in S. mansoni infection prevalence and intensity levels were achieved among school-age children regardless of the treatment approach used. |
A cross-sectional study on schistosomiasis and soil-transmitted helminths in Mbita district, western Kenya using different copromicroscopic techniques
Ng'etich AI , Rawago FO , Jura WG , Mwinzi PN , Won KY , Odiere MR . Parasit Vectors 2016 9 (1) 87 BACKGROUND: Identification of populations to be targeted for individual treatment and broad-spectrum therapy in schistosomiasis-endemic areas, assessment of therapy efficacy, morbidity, and evaluation of control strategies need to be based on reliable diagnostic tools. Kato-Katz is routinely used and remains the standard diagnostic technique for schistosomiasis, despite its many challenges. This study was conducted in Nyamanga village, Mbita, western Kenya, and evaluated the diagnostic performance of Kato-Katz, Mini-Parasep and modified Mini-FLOTAC techniques in detection of Schistosoma mansoni and soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura and hookworm) ova. METHODS: Stool samples from 132 individuals were screened for eggs of S. mansoni by the 3 techniques. Mini-Parasep(R) faecal parasite concentrator (Apacor Ltd, England), a single-use diagnostic device with a built-in filter for faecal concentration of helminth eggs by sedimentation was employed on stool samples fixed in 10 % formalin. A modified Mini-FLOTAC (University of Naples, Italy) was based on floatation of helminths eggs with two different solutions (FS2 and FS7) using a closed system (Fill-FLOTAC) with 5 % formalin. Kato-Katz was performed following WHO recommendation. Prevalence of S. mansoni and STH, sensitivity and degree of agreement among the 3 techniques were determined. RESULTS: Prevalence of S. mansoni was 47.0 %, 34.1 % and 20.5 % by Mini-Parasep, Kato-Katz and modified Mini-FLOTAC FS7 techniques, respectively. Prevalence of any STH infection was 6.1 %, 3.0 %, 6.1 % and 6.8 % by Mini-Parasep, Kato-Katz, modified Mini-FLOTAC FS2 and modified Mini-FLOTAC FS7 techniques, respectively. Considering the pooled results of the three methods (Mini-Parasep, Kato-Katz and modified Mini-FLOTAC FS7) as diagnostic 'gold' standard, the sensitivity of Mini-Parasep, Kato-Katz and modified Mini-FLOTAC FS7 for S. mansoni was 77.5 %, 56.1 %, and 33.8 %, respectively. Mini-Parasep and modified Mini-FLOTAC FS7 techniques had moderate (kappa = 0.46) and fairly good (kappa = 0.25) agreements with Kato-Katz for S. mansoni, respectively. Mini-Parasep detected a higher proportion of light intensity S. mansoni infections compared to Kato-Katz, which detected high proportions of heavy infections. Mini-Parasep detected a similar mean number of S. mansoni eggs per gram (EPG) of stool compared to the standard Kato-Katz (62.9 vs 97.3; t (131) = -0.49, P = 0.6265) and significantly higher EPG compared to the modified Mini-FLOTAC FS7 (62.9 vs 34.6; t (131) = 5.39, P < 0.0001). CONCLUSIONS: The high sensitivity of Mini-Parasep suggests its promising potential as an alternative tool in enhancing diagnosis and in monitoring schistosomiasis transmission and determining endpoint of intervention programs, especially in low endemicity areas. Mini-Parasep is also easy to operate, safe and also permits work with fresh stool. |
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. |
Evaluation of point-of-contact circulating cathodic antigen assays for the detection of Schistosoma mansoni infection in low-, moderate-, and high-prevalence schools in Western Kenya
Foo KT , Blackstock AJ , Ochola EA , Matete DO , Mwinzi PN , Montgomery SP , Karanja DM , Secor WE . Am J Trop Med Hyg 2015 92 (6) 1227-32 We evaluated the performance of a point-of-contact circulating cathodic antigen assay (POC-CCA) to detect schistosome infections in primary school children (N = 1,801) living in areas with low, moderate, and high Schistosoma mansoni prevalence in western Kenya. The commercially available assay (CCA-1) and a second, experimental formulation (CCA-2) were compared against Kato-Katz stool examinations and an anti-schistosome enzyme-linked immunosorbent assay (ELISA). A latent class model based on the four tests was used to establish "true infection status" in three different zones based on their distance from Lake Victoria. As a screening tool for community treatment according to World Health Organization (WHO) guidelines, the Kato-Katz examination was in closest agreement with the latent class model, followed by the experimental CCA-2, soluble adult worm antigen preparation (SWAP) ELISA, and CCA-1, which had high sensitivity compared with the other tests but was consistently the least specific. Our experience suggests that POC-CCA tests offer a field-friendly alternative to Kato-Katz, but need further interpretation for appropriate field use. |
Cost analysis of tests for the detection of Schistosoma mansoni infection in children in Western Kenya
Worrell CM , Bartoces M , Karanja DM , Ochola EA , Matete DO , Mwinzi PN , Montgomery SP , Secor WE . Am J Trop Med Hyg 2015 92 (6) 1233-9 Financial resources tend to be limited in schistosomiasis endemic areas, forcing program managers to balance financial and scientific considerations when selecting detection assays. Therefore, we compared the costs of using single stool Kato-Katz, triplicate stool Kato-Katz, and point-of-care circulating cathodic antigen (POC-CCA) assays for the detection of Schistosoma mansoni infection. Economic and financial costs were estimated from the viewpoint of a schistosomiasis control program using the ingredients approach. Costs related to specimen collection, sample processing and analysis, and treatment delivery were considered. Analysis inputs and assumptions were tested using one-way and two-way sensitivity analysis. The total per-person cost of performing the single Kato-Katz, triplicate Kato-Katz, and POC-CCA was US$6.89, US$17.54, and US$7.26, respectively. Major cost drivers included labor, transportation, and supplies. In addition, we provide a costing tool to guide program managers in evaluating detection costs in specific settings, as costs may vary temporally and spatially. |
Community knowledge, attitudes and practices on schistosomiasis in western Kenya - the SCORE Project
Musuva RM , Awiti A , Omedo M , Ogutu M , Secor WE , Montgomery SP , Alaii J , Mwinzi PN . Am J Trop Med Hyg 2014 90 (4) 646-52 In an effort to improve intervention strategies, community knowledge, attitudes, and practices on schistosomiasis were evaluated using focus group discussions involving 237 participants, in eight Schistosoma mansoni high prevalence districts in rural Nyanza Province, Kenya. The majority of participants reported having heard about schistosomiasis through schools, posters, radio announcements, and community gatherings. Participants had a variety of beliefs about contracting schistosomiasis, including associating it with dirty drinking water and uncooked or contaminated food. Avenues for seeking treatment included health centers, spiritual intervention, herbal treatments, and medicine shops, with health centers receiving the most mention. Barriers to schistosomiasis control included attitudes of community members toward the infection, especially misconceptions that lead to stigma and the perception that diagnosis and treatment are expensive. Schools were the most common avenue for receiving information, suggesting that the existing education infrastructure can be used for health education and improved sensitization about schistosomiasis control programs. |
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. |
Association between CD4+ T-lymphocyte counts and fecal excretion of schistosoma mansoni eggs in patients coinfected with S. mansoni and human immunodeficiency virus before and after initiation of antiretroviral therapy
Muok EM , Simiyu EW , Ochola EA , Ng'ang'a ZW , Secor WE , Karanja DM , Mwinzi PN . Am J Trop Med Hyg 2013 89 (1) 42-5 Previously, we have shown that persons with human immunodeficiency virus 1 (HIV-1) infection and reduced CD4(+) T-lymphocyte counts excrete significantly fewer Schistosoma mansoni eggs than HIV-1-negative persons with similar intensities of schistosome infections. To determine how antiretroviral therapy (ART) might affect egg excretion, we conducted a study of HIV+ adults living in an area highly endemic for S. mansoni as they began an ART program. Fecal egg excretion and CD4(+) T-lymphocyte counts were evaluated at enrollment as well as 2 and 4 weeks after initiation of ART. Fourteen individuals who were Kato-Katz-negative at enrollment subsequently started excreting S. mansoni eggs accompanied by a significant increase in CD4(+) T lymphocytes (P = 0.004). Study participants who were S. mansoni egg-positive at enrollment and received both praziquantel and ART also showed significantly increased CD4(+) T-lymphocyte counts compared with baseline (P < 0.0001). Our data support a role for CD4(+) T lymphocytes in S. mansoni egg excretion. |
High prevalence of schistosomiasis in Mbita and its adjacent islands of Lake Victoria, western Kenya
Odiere MR , Rawago FO , Ombok M , Secor WE , Karanja DM , Mwinzi PN , Lammie PJ , Won K . Parasit Vectors 2012 5 278 BACKGROUND: Intestinal schistosomiasis continues to be a significant cause of morbidity among communities located around Lake Victoria and on its islands. Although epidemiological surveys have been conducted in other areas bordering the lake in western Kenya, Mbita district and its adjacent islands have never been surveyed, largely due to logistical challenges in accessing these areas. Consequently, there is a paucity of data on prevalence of schistosomiasis and soil-transmitted helminth (STH) infections that are endemic in this region. METHODS: This cross-sectional study determined the prevalence, intensity of infection and geographical distribution of schistosome and STH infections among 4,065 children aged 5-19 years in 84 primary schools in Mbita and nearby islands of Lake Victoria (Mfangano, Ringiti, Rusinga and Takawiri), in western Kenya. Single stool samples were collected and examined for eggs of Schistosoma mansoni and STHs (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Primary schools were mapped using geographical information system data on PDAs and prevalence maps generated using ArcView GIS software. RESULTS: Overall, 65.6% (95% CI = 64.2-67.1%) of children were infected with one or more helminth species; 12.4% (95% CI = 11.4-13.4%) of children were infected with one or more STH species. Mean school prevalence of S. mansoni infection was 60.5% (95% CI = 59.0-62.0%), hookworms 8.4% (95% CI = 7.6-9.3%), A. lumbricoides 3.3% (95% CI = 2.7-3.8%), and T. trichiura 1.6% (95% CI = 1.2-2.0%). Interestingly, the mean S. mansoni prevalence was 2-fold higher on the islands (82%) compared to the mainland (41%) (z = 5.8755, P < 0.0001). Similarly, intensity of infection was 54% higher on the islands (217.2 +/- 99.3) compared to the mainland (141.3 +/- 123.7) (z = 3.9374, P < 0.0001). Schools in closest proximity to Lake Victoria had the highest S. mansoni prevalence while prevalence of STHs was more homogenously distributed. CONCLUSIONS: The very high prevalence of schistosomiasis in Mbita and the 4 islands is quite alarming, and indicates an urgent and critical need for control interventions. Findings from this survey indicate the need to implement treatment in remote areas not previously covered by mass drug administration programs. |
Community health workers experiences and perspectives on mass drug administration for Schistosomiasis control in western Kenya: the SCORE project
Omedo MO , Matey EJ , Awiti A , Ogutu M , Alaii J , Karanja DM , Montgomery SP , Secor WE , Mwinzi PN . Am J Trop Med Hyg 2012 87 (6) 1065-72 The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) includes communitywide treatment in areas with ≥ 25% prevalence of schistosomiasis along the shores of Lake Victoria using community health workers (CHWs). The CHWs are key drivers in community-owned mass drug administration (MDA) intervention programs. We explored their experiences and perceptions after initial MDA participation. Unstructured open-ended group discussions were conducted after completion of MDA activities. Narratives were obtained from CHWs using a digital audio recorder during the group discussion, transcribed verbatim and translated into English where applicable. Thematic decomposition of data was done using ATLAS.t.i. software. From the perspective of the CHWs, factors influencing MDA compliance included drug side effects, food supply stability, and conspiracy theories about the "real" purpose of treatment. The interest of CHWs to serve as community drug distributors stemmed from both intrinsic and extrinsic factors. Feedback from CHWs can promote more effective MDA in rural Kenyan communities. |
Schistosoma mansoni morbidity among school-aged children: a SCORE project in Kenya
Samuels AM , Matey E , Mwinzi PN , Wiegand R , Muchiri G , Ireri E , Hyde M , Montgomery SP , Karanja DM , Secor WE . Am J Trop Med Hyg 2012 87 (5) 874-82 Schistosomiasis control programs aim to reduce morbidity but are evaluated by infection prevalence and intensity reduction. We present baseline cross-sectional data from a nested cohort study comparing indicators of morbidity for measuring program impact. Eight hundred twenty-two schoolchildren 7-8 years of age from Nyanza Province, Kenya, contributed stool for diagnosis of Schistosoma mansoni and soil-transmitted helminths (STH) and blood smears for malaria, and were evaluated for anemia, quality of life, exercise tolerance, anthropometry, and ultrasound abnormalities. Schistosoma mansoni, STH, and malaria infection prevalence were 69%, 25%, and 8%, respectively. Only anemia and S. mansoni infection (adjusted odds ratio [aOR] = 1.70; confidence interval [CI] = 1.03-2.80), and hepatomegaly and heavy S. mansoni infection (aOR = 2.21; CI = 1.19-4.11) were associated. Though anemia and hepatomegaly appeared most useful at baseline, additional morbidity indicators may be sensitive longitudinal measures to evaluate schistosomiasis program health impact. |
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. |
Identification of cytokeratin-18 as a biomarker of mouse and human hepatosplenic schistosomiasis
Manivannan B , Rawson P , Jordan TW , Karanja DM , Mwinzi PN , Secor WE , La Flamme AC . Infect Immun 2011 79 (5) 2051-8 Previously, we demonstrated unique protein expression patterns in 20-week Schistosoma mansoni-infected CBA/J mice with moderate splenomegaly syndrome (MSS) or hypersplemomegaly syndrome (HSS). To better understand development of severe pathology, we compared the 2D-DIGE (two-dimensional differential in gel electrophoresis) proteomic signatures of livers from uninfected mice and mice infected for 6, 8, 12, or 20-weeks and found significant changes in collagen isoforms, IL-2, cytokeratin 18, hydroxyproline, S. mansoni-phosphoenolpyruvate carboxykinase, major urinary protein isoforms and peroxiredoxin 6. Cytokeratin 18, hydroxyproline, and connective tissue growth factor (CTGF) were chosen for analysis in mouse and human sera using targeted biochemical assays. Consistent with the liver analysis, cytokeratin 18, CTGF and hydroxyproline were significantly elevated in HSS mouse serum compared to uninfected or MSS mice. Moreover, cytokeratin 18 and CTGF were found to be markers for hepatosplenic and intestinal schistosomiasis subjects, respectively, while serum hydroxyproline was a strong indicator of fibrosis for severe HS. These findings indicate that schistosome-associated changes to the liver can be detected in the serum and reveal the potential for cytokeratin-18 to be used as a diagnostic marker for early detection of hepatosplenic schistosomiasis. |
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. |
Increases in levels of schistosome-specific immunoglobulin E and CD23(+) B cells in a cohort of Kenyan children undergoing repeated treatment and reinfection with Schistosoma mansoni
Black CL , Muok EM , Mwinzi PN , Carter JM , Karanja DM , Secor WE , Colley DG . J Infect Dis 2010 202 (3) 399-405 BACKGROUND: Age prevalence curves for areas in which schistosomiasis is endemic suggest that humans develop partial immunity to reinfection beginning in early adolescence. We conducted a 2-year longitudinal study to determine whether children infected with Schistosoma mansoni develop protection-related immune responses after treatment with praziquantel and whether the development of these immune responses is accelerated by frequent treatment after reinfection. METHODS: Children (8-10 years old) were tested for S. mansoni every 4 months and treated with praziquantel when positive (arm A; [Formula: see text]) or were tested and treated at the end of the 2-year follow-up period (arm B; [Formula: see text]). RESULTS: Children in arm A who remained free of infection during follow-up had significantly higher baseline levels of schistosome-specific immunoglobulin E (IgE) than did children with 2 repeat diagnoses of S. mansoni infection. Children with 2 repeat diagnoses of S. mansoni infection had significantly increased levels of anti-schistosome IgE and CD23(+) B cells after receiving 3 praziquantel treatments over the course of follow-up. No increase in either parameter was seen in children who received only the baseline praziquantel treatment. CONCLUSIONS: B cell activation and anti-schistosome IgE are associated with resistance to S. mansoni in children, and these immunological parameters can be increased by multiple rounds of infections and praziquantel-induced cures. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 06, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure