title: Soil-transmitted helminth reinfection after drug treatment: a systematic review and meta-analysis.
abstract: BACKGROUND
  Soil-transmitted helminth (STH) infections (i.e., Ascaris lumbricoides, hookworm, and Trichuris trichiura) affect more than a billion people. Preventive chemotherapy (i.e., repeated administration of anthelmintic drugs to at-risk populations), is the mainstay of control. This strategy, however, does not prevent reinfection. We performed a systematic review and meta-analysis to assess patterns and dynamics of STH reinfection after drug treatment.
  
  
  METHODS
  We systematically searched PubMed, ISI Web of Science, EMBASE, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure, WanFang Database, Chinese Scientific Journal Database, and Google Scholar. Information on study year, country, sample size, age of participants, diagnostic method, drug administration strategy, prevalence and intensity of infection pre- and posttreatment, cure and egg reduction rate, evaluation period posttreatment, and adherence was extracted. Pooled risk ratios from random-effects models were used to assess the risk of STH reinfection after treatment. Our protocol is available on PROSPERO, registration number: CRD42011001678.
  
  
  RESULTS
  From 154 studies identified, 51 were included and 24 provided STH infection rates pre- and posttreatment, whereas 42 reported determinants of predisposition to reinfection. At 3, 6, and 12 months posttreatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16-43%), 68% (95% CI: 60-76%) and 94% (95% CI: 88-100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence were 36% (95% CI: 28-47%), 67% (95% CI: 42-100%), and 82% (95% CI: 62-100%), and for hookworm, 30% (95% CI: 26-34%), 55% (95% CI: 34-87%), and 57% (95% CI: 49-67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status.
  
  
  CONCLUSIONS
  STH reinfections occur rapidly after treatment, particularly for A. lumbricoides and T. trichiura. Hence, there is a need for frequent anthelmintic drug administrations to maximize the benefit of preventive chemotherapy. Integrated control approaches emphasizing health education and environmental sanitation are needed to interrupt transmission of STH.
authors.affiliation: Key Laboratory on Biology of Parasites and Vectors, MOH, WHO Collaborating Center on Malaria, Schistosomiasis and Filariasis, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China. jiatiewu@sina.com
authors.forename: Tie-Wu
authors.initials: TW
authors.lastname: Jia
authors.forename: Sara
authors.initials: S
authors.lastname: Melville
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.forename: Charles H
authors.initials: CH
authors.lastname: King
authors.forename: Xiao-Nong
authors.initials: XN
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage*; D001196:Ascariasis / Q000188:drug therapy*; D004358:Drug Therapy / Q000379:methods; D006373:Helminthiasis / Q000188:drug therapy*; D006725:Hookworm Infections / Q000188:drug therapy*; D006801:Humans; D012008:Recurrence; D014257:Trichuriasis / Q000188:drug therapy*
chemical_list: D000871:Anthelmintics