Diverse Antigen-specific Antibody and Atopic Responses In Schistosomiasis and Malaria Co-infected Individuals.
Paul, Noah H.
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The study was part of a huge schistosomiasis survey investigating schistosomiasis in the human model and was conducted in the Mashonaland East Province of Zimbabwe (31o 30‘E; 17o 45‘S) at Magaya and Chitate schools where S. haematobium is endemic and sporadic P. falciparum transmission. The study aimed at determining schistosomiasis and malaria infection prevalences, antibody response modulation during co-infections and the effect of helminths and helminth treatment on co-infections and allergic disorders. A community based longitudinal intervention study was conducted that involved examination and treatment of the study population at baseline, 6 weeks, 6 months, and 12 months follow up surveys. Urine and faecal samples were collected at baseline on three consecutive days and were processed for schistosomiasis using the Kato Katz, Formol-ether concentration method. Blood samples were obtained and the serum was separated and used to determine immunological profiles against diverse anti-parasite antigen (S. haematobium and P. falciparum). Malaria infection was detected by thick film slide microscopy. An allergen reaction test, skin prick, was done on mother and child only to determine the reaction to six different allergens on the child/parent‘s forearm. A single dose of praziquantel was given to infected participants at recommended dose of 40mg/kg body weight. Data was captured using SPSS 8.0. The study established that the sampling areas differed in levels of intensity and prevalence of schistosome infection. Schistosome infection levels were significantly higher in Magaya (prevalence = 68%), than in Chitate (prevalence = 14%, p<0.001) with mean infection intensity of 58 eggs/10ml urine and 15 eggs/10ml urine respectively (p < 0.001). Overall, S. haematobium infection prevalence in the study population was 56%. All the participants investigated produced IgM antibodies directed against all the three life stages of the S. haematobium (cercariae, adult worms and eggs). Malaria infection was not detected by microscopy, and by rapid test kit, although anti-P .falciparum schizonts antibodies were detected. The prevalence of allergies in the population was 19 % and 12 % of those were allergic to the house dust mite allergy. The prevalence of autoimmune reactivity was significantly higher in Chitate the (WHO classification) moderate infection area 48% than in Magaya the high infection area 22% (p < 0.001). The prevalence of autoimmune reactivity was significantly lower in schistosome positive people compared to schistosome negative people (Magaya, p < 0.05 and Chitate p < 0.05). There was huge evidence that lack of knowledge was hampering eradication efforts from questionnaire assessment of the knowledge, attitudes and practices of the communities. Praziquantel was remained highly efficacious in schistosomiasis treatment, with 98 % efficacy. The inclusion of infants into the praziquantel mass treatment scheme proved to be a safer risk to take as only 4/84 of those assessed complained of the side effects of praziquantel treatment. The detection of malaria in these low transmission set ups has to be augmented with sub-microscopic PCR detection, since the current treatment regimen and the low transmission pattern may make it difficult for correct diagnosis of malaria. The study also demonstrated that a balance between levels of atopic IgE and IgG4 plays an important part in regulation of atopic disorders. Anti-schistosome treatment with praziquantel did not result in an increase in atopic responses 6 months after treatment in children aged 6 months to 5 years of age. Praziquantel treatment resulted in a significant increase in parasite-specific IgE, which has been associated with resistance to re-infection. The success of control programmes in this area will be greatly increased by educating parents/guardians of children on bilharzia, malaria and other related parasitic infections.