RESUMO
This study evaluated potential changes in antischistosome immune responses in children from schools that received 4 rounds of annual mass drug administration (MDA) of praziquantel (PZQ). 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 with schistosome infection by microscopy (post-MDA group). In-vitro schistosome-specific cytokines and plasma antibody levels were measured by ELISA and compared between the 2 groups of children. 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. These post-MDA immunological changes are compatible with the current paradigm that treatment shifts immune responses to higher antischistosome IgE:IgG4 ratios in parallel with a potential increase in resistance to reinfection.
Assuntos
Anti-Helmínticos/uso terapêutico , Anticorpos Anti-Helmínticos/sangue , Mebendazol/uso terapêutico , Praziquantel/uso terapêutico , Schistosoma mansoni/efeitos dos fármacos , Schistosoma mansoni/imunologia , Esquistossomose mansoni/tratamento farmacológico , Adolescente , Animais , Criança , Estudos Transversais , Citocinas/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Fenômenos do Sistema Imunitário , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Quênia , Masculino , Esquistossomose mansoni/prevenção & controleRESUMO
OBJECTIVE: To determine whether drug treatment of Schistosomiasis mansoni infection leads to a reduction in plasma HIV-1 RNA concentration in coinfected individuals. METHODS: Stool and plasma samples were obtained prospectively from a cohort of HIV-infected persons (n = 30) in Kisumu, Kenya, before and after treatment of schistosomiasis with praziquantel (mean follow-up, 5.6 months; range 1-15 months). Schistosomal circulating cathodic antigen (CCA) concentrations in plasma were determined by ELISA and fecal egg counts were determined by microscopy. HIV-1 RNA concentrations were measured in pre- and post-treatment plasma samples obtained from the patients whose stool samples remained free of schistosomal eggs for the great majority of the follow-up period. RESULTS: Comparison of pretreatment and follow-up samples revealed that mean +/- SD fecal egg burden was reduced by 96.7% (481.5+/-803.5 versus 16.1+/-24.4 eggs/g feces) and mean plasma CCA concentration decreased by 90.1% (3.22+/-3.26 versus 0.32+/-0.38 microg/ml). In contrast, mean plasma HIV-1 load increased from 3.60+/-0.90 to 3.93+/-0.95 log10 RNA copies/ml (P< 0.001). Although no correlation was found between changes in HIV-1 load and changes in schistosomal burden, there was a significant correlation between changes in plasma HIV load and the time interval between pretreatment and follow-up samples (r = 0.41; P = 0.027). CONCLUSIONS: Treatment of schistosomiasis was not associated with a reduction in plasma HIV-1 load. This study does not, however, exclude the possibility of an adverse effect of helminthic infections on HIV-1 pathogenesis.
Assuntos
Anti-Helmínticos/uso terapêutico , Infecções por HIV/virologia , Praziquantel/uso terapêutico , RNA Viral/sangue , Esquistossomose mansoni/tratamento farmacológico , Adulto , Animais , Antígenos de Helmintos/sangue , Fezes/parasitologia , Infecções por HIV/complicações , Infecções por HIV/imunologia , HIV-1/fisiologia , Humanos , Masculino , Contagem de Ovos de Parasitas , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/complicaçõesRESUMO
Persons employed as vehicle washers in the town of Kisumu, Kenya are exposed for several hours each day to water in Lake Victoria that contains Schistosoma mansoni-infected Biomphalaria pherifferi snails. This results in a focus of high endemicity for schistosomiasis and these persons have very high concentrations of eggs in their feces (mean +/- SD = 1,469 +/- 1,581 eggs per gram [EPG] of feces). Fecal egg counts, but not circulating cathodic antigen (CCA) levels, in these schistosomiasis patients differed strikingly based on the patient's seropositivity for human immunodeficiency virus (HIV). Patients who were infected with S. mansoni and were seropositive for HIV had similar levels of CCA but excreted fewer eggs (643 +/- 622 EPG; n = 16) than individuals who were not seropositive for HIV infection (1,891 +/- 1,779 EPG; n = 37) (P = 0.009). Egg excretion ratios (EPG/CCA) of the seronegative group were also significantly higher than those of the seropositive group. Those in the seropositive group showed a significant correlative relationship between egg excretion ratios and CD4+ lymphocyte percentages. These observations are compatible with the hypothesis that schistosome eggs exit the human host through the requisite facilitation of functional immune responses, and that the efficacy of this process decreases in schistosomiasis patients co-infected with HIV as their peripheral blood CD4- cell levels decrease.
Assuntos
Infecções por HIV/parasitologia , Doenças Profissionais/imunologia , Esquistossomose mansoni/imunologia , Adulto , Antígenos de Helmintos/sangue , Linfócitos T CD4-Positivos/imunologia , Humanos , Contagem de Ovos de Parasitas , Esquistossomose mansoni/parasitologia , Fator de Necrose Tumoral alfa/análiseRESUMO
Praziquantel is the drug of choice for schistosomiasis chemotherapy. Although the exact mechanism of how praziquantel kills schistosomes remains poorly understood, the immune response of the host is an important factor in drug efficacy. It is thus possible that disease states of humans that lead to immunodeficiencies, such as infection with human immunodeficiency virus-1 (HIV-1), may render praziquantel less effective in treating schistosomiasis. To test this hypothesis, persons with high levels of Schistosoma mansoni infection who were or were not also infected with HIV-1 were treated with a standard regimen of praziquantel and monitored by quantitative fecal examination and plasma circulating cathodic antigen. Both groups responded to praziquantel therapy equally and individuals with low percentages (< 20%) of CD4+ T cells did not differ from individuals with higher CD4 cell percentages. These data demonstrate that persons with HIV-1 infection can be treated effectively for schistosomiasis with praziquantel.
Assuntos
Antiplatelmínticos/uso terapêutico , Infecções por HIV/complicações , HIV-1 , Praziquantel/uso terapêutico , Esquistossomose mansoni/tratamento farmacológico , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/sangue , Antígenos de Helmintos/imunologia , Contagem de Linfócito CD4 , Fezes/parasitologia , Seguimentos , Glicoproteínas/sangue , Infecções por HIV/imunologia , Proteínas de Helminto/sangue , Humanos , Quênia , Contagem de Ovos de Parasitas , Recidiva , Schistosoma mansoni/imunologia , Esquistossomose mansoni/complicações , Esquistossomose mansoni/imunologiaRESUMO
A field trial was conducted to test the insecticidal action of the monolayer surface film 'Arosurf MSF' applied by knapsack sprayers, against larvae and pupae of Anopheles arabiensis Patton in a rice irrigation scheme in Western Kenya. Larval and pupal densities and the number of emerging adults were determined by dipping and emergence cages respectively. Application of the monolayer by knapsack sprayers provided good coverage. There were high daily mortalities of the fourth instar larvae, with no adult emergence from 'Arosurf MSF' treated plots compared to lower fourth instar mortalities and continuous adult emergence from untreated control plots, indicating the potential of the monolayer for control of An. arabiensis mosquitoes in rice fields.
Assuntos
Anopheles , Álcoois Graxos , Insetos Vetores , Controle de Mosquitos/métodos , Polietilenoglicóis , Tensoativos , Animais , Quênia , Larva , Oryza , PupaRESUMO
OBJECTIVES: The objectives of this study were to conduct a survey on the knowledge and practices relating to malaria prevention and treatment in two rural communities in Western Kenya, and to determine the acceptability of specially designed permethrin impregnated sisal strands curtains previously introduced into one of the study communities as barriers to mosquito biting. DESIGN: A knowledge, attitudes and practices (KAP) survey was conducted by pre-trained interviewers using a pre-tested questionnaire. SETTING: The study was conducted in two communities located 15 km northwest of Kisumu town, and next to the swamps bordering Lake Victoria in Kisumu District, Western Kenya. PARTICIPANTS: Adult individuals from 50 houses selected from the intervention, and 50 houses from the control sites were included in the study. RESULTS: Both communities had a clear conception of malaria and its symptoms, and of the mosquito as its vector. Malaria was recognised as a potential cause of death by 44% and 72% of the participants in the intervention and control sites respectively. Sixty two per cent to 74% of the people interviewed in both sites named mosquitoes as the causative agents of malaria. Chloroquine was still the drug of choice for malaria treatment, with over 70% usage among the study population. Mention of pyrimethamine/sulfadoxine and pyrimethamine/sulfalene as alternative therapy was below five per cent. Despite a high level (86%) of awareness of bednets as effective barriers to mosquito biting, they were reported in use by less than 35% in both communities. Sisal strand curtains were considered effective and acceptable to more than 80% of the community. CONCLUSIONS: The results of this study underscore the existing need for affordable means of mosquito control, such as sisal strand curtains, for such rural communities which may be acutely aware of the problems associated with malaria, but are constrained from taking any action by lack of resources.
Assuntos
Roupas de Cama, Mesa e Banho , Conhecimentos, Atitudes e Prática em Saúde , Inseticidas/administração & dosagem , Malária/prevenção & controle , Controle de Mosquitos/métodos , Piretrinas/administração & dosagem , Adulto , Feminino , Humanos , Quênia , Masculino , Medicinas Tradicionais Africanas , Aceitação pelo Paciente de Cuidados de Saúde , Permetrina , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: Almost 1 billion individuals lack access to improved water supplies, with 2.6 billion lacking adequate sanitation. This leads to the propagation of multiple waterborne diseases. The objective of this study was to explore local knowledge, attitudes and practices to understand the mechanisms and pre-conditions for sustainable uptake and use of these facilities. METHODS: Data collection took place in a rural Kenyan community in September 2009. A qualitative approach was taken, with 4 focus groups and 25 in-depth interviews conducted. Participant characteristics varied by age, gender, education, marital status, employment and community standing. RESULTS: Few participants reported current access to improved water and sanitation facilities. Though they expressed desire for latrines and water sources, barriers including lack of funds and social capital, decrease the ability for installation. Participants understood that there was a link between the quality of water and their health, however, perceived benefits of current contaminated sources outweigh the potential health impacts and proliferate their continued use. CONCLUSION(S): While water-health links are understood to varying degrees within the community, contextual (physical environment), compositional (individual) and collective (community) factors interact to influence health. Community challenges, such as lack of unity, lack of education and lack control were identified as the main barriers to initiating change, despite a desire for increased access to safe water and sanitation.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Saúde da População Rural , Saneamento , Abastecimento de Água , Água Potável , Feminino , Grupos Focais , Inquéritos Epidemiológicos , Humanos , Higiene , Masculino , Saúde Pública , Pesquisa Qualitativa , Características de Residência , População Rural , Fatores Socioeconômicos , Inquéritos e QuestionáriosRESUMO
In vitro studies suggest that CD4(+) cells with a T helper 2 (Th2) phenotype better support human immunodeficiency virus type 1 (HIV-1) replication than do cells of the Th1 phenotype. As a result, Th2-type immune responses may be substantially affected by HIV-1 coinfection. To test this hypothesis, a comparison was done of proliferation and cytokine production by peripheral blood mononuclear cells from patients with schistosomiasis who were positive or negative for HIV-1. Patients with schistosomiasis with HIV-1 coinfections had significantly lower interleukin (IL)-4 and IL-10 production than did HIV-1-negative individuals. In contrast, interferon-gamma production levels were similar between the 2 groups. Furthermore, in patients with HIV-1, a decrease in CD4(+) T cells was correlated with an increased Th1:Th2 cytokine production ratio. The effect of praziquantel treatment on proliferation and cytokine responses also differed between HIV-1 infection groups. Thus, HIV-1 infection affects immune response patterns of patients with schistosomiasis.
Assuntos
Infecções por HIV/complicações , HIV-1/imunologia , Leucócitos Mononucleares/imunologia , Schistosoma mansoni/imunologia , Esquistossomose mansoni/imunologia , Adolescente , Adulto , Animais , Anti-Helmínticos/uso terapêutico , Contagem de Linfócito CD4 , Células Cultivadas , Citocinas/biossíntese , Humanos , Ativação Linfocitária , Praziquantel/uso terapêutico , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/complicações , Esquistossomose mansoni/tratamento farmacológicoRESUMO
Studies were carried out in three villages in western Kenya on the biting behavior of Anopheles gambiae s.s., Anopheles arabiensis, and Anopheles funestus. Blood feeding behavior and departure from houses were studied under the impact of permethrin-impregnated eaves-sisal curtains. Only 2-13% of the female vector population was collected biting before 2200 hr. Over 90% of the villagers went to bed by 2100 hr. An. funestus was 6.6-8.2 times more likely to bite people indoors than outdoors, while An. gambiae s.l. females were only 2 times as likely. Under the influence of permethrin-impregnated sisal curtains placed under the eaves of village houses, there was a marked egress of blood-fed An. funestus and An. gambiae s.s. Permethrin seems to have induced exophily of half-gravid female An. gambiae s.s. While An. gambiae s.s. remained highly anthropophagic under the impact of permethrin, An. funestus shifted to feeding more on cattle. An arabiensis were largely zoophilic. Our results underline the difficulties of controlling An. gambiae s.s., the principal African malaria vector. New strategies must be found to control this vector.