Diagnosis, epidemiology and control of soil-transmitted helminth infection in Zanzibar, Tanzania

摘要: Soil-transmitted helminths are intestinal parasitic worms that isproportionally affect socio-economically deprived populations in tropical and subtropical countries living under poor hygienic conditions. The transmitted by the contamination of soil with human faeces containing worms’ eggs subsequent accidental ingestion contaminated food or hands, penetration worm larvae into skin body humans. global burden attributed to soil-transmitted helminth infections is estimated be as high 39 million disability-adjusted life years (DALYs) lost annually. Children pregnant women groups at highest risk morbidity. World Health Organization (WHO) widely advocates periodical deworming school-aged children strategy control morbidity associated infections. A target reach a minimum treatment coverage 75% 2010 was set Assembly May 2001. In Zanzibar, Tanzania, helminthiases were recognized major public health issue early 1990s, 85% surveyed population infected least one species, namely Ascaris lumbricoides, hookworms (Ancylostoma duodenale Necator americanus) Trichuris trichiura. Infections Strongyloides stercoralis, arguably most neglected soiltransmitted helminth, found 40% schoolchildren examined rural Zanzibar. 1994 2001 national programmes implemented Ministry Social Welfare (MoHSW) Since then, anthelminthic drugs have been administered annually other eligible Zanzibar more than 80% reached. overreaching goal this PhD thesis deepen our understanding epidemiology There three specific objectives. First, compare evaluate different diagnostic techniques for detection Second, determine current factors infections, including S. environmentally distinct settings on Unguja. Third, assess long-term effect periodic prevalences infection intensities, assessment efficacy safety albendazole mebendazole alone combination ivermectin against T. trichiura fieldwork split parts. 2007, an epidemiological situation Unguja, crosssectional study conducted five madrassas primary schools six districts Unguja included 336 children. Additionally, cross-sectional 401 carried out Chaani Kinyasini schools. parasitological results compared data derived same Multiple stool samples collected from each participant over consecutive days. Kato-Katz method employed diagnosis A. hookworm trichiura, Koga-agar plate stercoralis Baermann stercoralis. Moreover, preserved sodium acetate-acetic acid-formalin (SAF) transferred Italy FLOTAC method. sensitivity individual methods combinations compared. 2008, peri-urban setting 658 individuals aged 5-100 enrolled. Besides determination aforementioned methods, urine analysed Schistosoma haematobium blood anaemia antibodies participants interviewed questionnaire behavioural signs. both juxtaposed activities 2009, randomised controlled trial out, comparing monotherapies therapy. During baseline screening 1240 Kilombero (n=610) assigned four arms. For diagnosis, thick smears before 3-5 weeks after outcomes After several prevalence still high, ranging between 22% urban 70% North district. Infection intensities mostly light, hence based egg-positivity sample has become challenge. coprological can increased (i) rigorous adherence bench aids provided WHO (Kato-Katz method); (ii) examination multiple per individual; (iii) examinations sample; (iv) methods. shows lumbricoides (~80%) (~90%). However, needs further evaluation standardization produce reliable diagnosis. Its potential application resource-poor its suitability drug additional investigation. On prevalent species common, particularly areas. Anaemia prevalent, but not any study. Risk setting- species-specific include, besides demographic factors, consumption raw vegetables salad, no hand-washing defecation recent travel history. predominant school (71%). contrast (-77%) (-71%), markedly reduced past (-46%). This phenomenon explained low efficacies (cure rate (CR): 10%; egg reduction (ERR): 40%) (CR: 19%; ERR: 67%) commonly applied Zanzibar’s school-based programmes. addition 55%; 97%), also 38%; 91%) Both highly efficacious (ERR: >99%). outcome 59%; 94%) better 35%; ERR:78%) did improve outcomes. Adverse events mild disappeared within 48 hours treatment, differ regimens. CRs assessed lower all species. successfully Poverty alleviation accompanied access households improved sanitation likely rate. now focus transmission control, will need revise measures sustainable progress. Alternation should considered effectively ectoparasites, combined whenever people kind new cannot prevented alone, because responsible majority cured ineffectively currently available drugs, increase hygiene indispensable elsewhere. far-reaching dissemination appealing plausible education communication communities necessary create environment community-led improvements (latrine construction, sewage disposal clean water), assure their adequate use. Only consent wish local scale, hand-in-hand governmental nongovernmental supported poverty finally result elimination