Publications by authors named "Walter G Z O Jura"

Background: The impact of preexisting immunity on the efficacy of artemisinin combination therapy must be examined to monitor resistance, and for implementation of new treatment strategies.

Methods: Serum samples obtained from a clinical trial in Western Kenya randomized to receive artemether-lumefantrine (AL) or artesunate-mefloquine (ASMQ) were screened for total immunoglobulin G against preerythrocytic and erythrocytic antigens. The association and correlation between different variables, and impact of preexisting immunity on parasite slope half-life (t½) was determined.

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Background: Use of chloroquine, an otherwise safe and relatively affordable anti-malarial drug, was discontinued due to widespread prevalence of resistant parasites. Many entrant anti-malarial drugs for treatment of chloroquine resistant malaria raises the concerns of cost and safety among other challenges. Innovative ways of circumventing chloroquine resistance is of paramount importance.

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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.

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Doxycycline is widely used for malaria prophylaxis by international travelers. However, there is limited information on doxycycline efficacy in Kenya, and genetic polymorphisms associated with reduced efficacy are not well defined. In vitro doxycycline susceptibility profiles for 96 Plasmodium falciparum field isolates from Kenya were determined.

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Background: Human Immunodeficiency Virus (HIV) and Schistosomiasis co-infection is common among residents at the shores of Lake Victoria in Kenya. About 36% of this population initiating antiretroviral therapy (ART) experience Immune Reconstitution Inflammatory Syndrome (IRIS) that complicates recovery. Several IL-23R alleles have been associated with susceptibility to both autoimmune and inflammatory diseases through T-helper type 17 (TH17) cells.

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Endemic Burkitt lymphoma (eBL) is associated with Epstein-Barr virus (EBV) and Plasmodium falciparum coinfections. Malaria appears to dysregulate immunity that would otherwise control EBV, thereby contributing to eBL etiology. Juxtaposed to human genetic variants associated with protection from malaria, it has been hypothesized that such variants could decrease eBL susceptibility, historically referred to as "the protective hypothesis.

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Clinical immunity to malaria declines in the absence of repeated parasite exposure. However, little is known about how B cell populations and antigen-specific memory B cells change in the absence of P. falciparum infection.

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High levels of environmental contamination, often associated with improper waste and excreta management, are widespread among informal settlements within urban areas in developing countries. We determined the level of faecal contamination in domestic water sources and evaluated the potential contribution of these water sources to intestinal helminthiases in seven informal settlements of Kisumu City, western Kenya. Membrane filtration technique was used for enumeration of total and faecal (Escherichia coli) coliform bacteria in water samples collected from dams, rivers, springs and wells.

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Background: Plasmodium falciparum infection leads to alterations in B cell subset distribution. During infancy, development of peripheral B cell subsets is also occurring. However, it is unknown if infants living a malaria endemic region have alterations in B cell subsets that is independent of an age effect.

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Background: Although schistosomiasis is generally considered a rural phenomenon, infections have been reported within urban settings. Based on observations of high prevalence of Schistosoma mansoni infection in schools within the informal settlements of Kisumu City, a follow-up malacological survey incorporating 81 sites within 6 informal settlements of the City was conducted to determine the presence of intermediate host snails and ascertain whether active transmission was occurring within these areas.

Methods: Surveyed sites were mapped using a geographical information system.

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This cross-sectional study determined the prevalence and distribution of schistosome and soil-transmitted helminth (STH) infections among 1,308 children aged 10-18 years in 34 primary schools in 8 informal urban settlements in Kisumu City, western Kenya. Stool samples were collected and examined for eggs of Schistosoma mansoni and STH (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Haematuria was used as a proxy indicator of urinary schistosomiasis.

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Background: The appropriate use of anti-malarial drugs determines therapeutic efficacy and the emergence and spread of drug-resistant malaria. Strategies for improving drug compliance require accurate information about current practices at the consumer level. This is to ascertain that the currently applied new combination therapy to malaria treatment will achieve sustained cure rates and protection against parasite resistance.

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Background: Interventions to reverse trends in malaria-related morbidity and mortality in Kenya focus on preventive strategies and drug efficacy. However, the pattern of use of anti-malarials in malaria-endemic populations, such as in western Kenya, is still poorly understood. It is critical to understand the patterns of anti-malarial drug use to ascertain that the currently applied new combination therapy to malaria treatment, will achieve sustained cure rates and protection against parasite resistance.

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