title: Effect of Wuchereria bancrofti infection on HIV incidence in southwest Tanzania: a prospective cohort study.
abstract: The past decades have seen an ongoing controversial debate about whether the immune activation induced by helminths has an effect on the susceptibility of individuals to HIV. In view of this, we assessed the effect of lymphatic filariasis, a chronic helminth disease elicited by Wuchereria bancrofti, on HIV incidence in southwest Tanzania.
  
  
  
  In this population-based cohort study, we enrolled a geographically stratified randomly chosen sample of about 10% of the households in nine distinct sites in southwest Tanzania. All household members present were followed up and tested for HIV and circulating filarial antigen, an indicator of W bancrofti adult worm burden. Our main outcome of interest was HIV incidence in participants with or without lymphatic filariasis.
  
  
  
  Between May 29, 2006, and June 16, 2011, we enrolled 4283 households with roughly 18 000 participants. Of these, 2699 individuals from Kyela district participated in at least one round of the EMINI study. In the 1055 initially HIV-negative adolescents and adults with clearly defined lymphatic filariasis status, 32 new HIV infections were observed in 2626 person-years. HIV incidence in lymphatic filariasis-positive participants (1·91 cases per 100 person-years) was significantly higher than the incidence in lymphatic filariasis-negative participants (0·80 cases per 100 person-years). The age-adjusted and sex-adjusted incidence rate ratio was 2·17 (95% CI 1·08-4·37, p=0·0300). Lymphatic filariasis status remained an independent and significantly relevant risk factor for HIV infection when controlled for other known risk factors such as sexual behaviour and socioeconomic factors.
  
  
  
  To our knowledge, this is the first prospective study demonstrating a significantly increased risk of acquiring HIV for lymphatic filariasis-infected individuals. Immunological studies and interventional treatment studies that eliminate the adult worms and not only the microfilariae are needed to follow up on the results presented.
  
  
  
  European Union as part of EuropAid; German Federal Ministry of Education and Research; German Center for Infection Research.
authors: Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; National Institute of Medical Research, Mbeya Medical Research Centre, Mbeya, Tanzania; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany. Electronic address: ikroidl@lrz.uni-muenchen.de.
authors: Inge
authors: I
authors: Kroidl
authors: Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Elmar
authors: E
authors: Saathoff
authors: National Institute of Medical Research, Mbeya Medical Research Centre, Mbeya, Tanzania.
authors: Lucas
authors: L
authors: Maganga
authors: National Institute of Medical Research, Tanga, Tanzania.
authors: Williams H
authors: WH
authors: Makunde
authors: Institute of Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany; German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn-Cologne, Germany.
authors: Achim
authors: A
authors: Hoerauf
authors: Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Christof
authors: C
authors: Geldmacher
authors: National Institute of Medical Research, Mbeya Medical Research Centre, Mbeya, Tanzania.
authors: Petra
authors: P
authors: Clowes
authors: National Institute of Medical Research, Mbeya Medical Research Centre, Mbeya, Tanzania.
authors: Leonard
authors: L
authors: Maboko
authors: Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; National Institute of Medical Research, Mbeya Medical Research Centre, Mbeya, Tanzania; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Michael
authors: M
authors: Hoelscher
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000947:Antigens, Helminth / Q000097:blood*; D002944:Circumcision, Male; D004605:Elephantiasis, Filarial / Q000453:epidemiology* / Q000276:immunology*; D019353:Endemic Diseases / Q000706:statistics & numerical data; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000276:immunology*; D006801:Humans; D015994:Incidence; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012494:Sampling Studies; D012747:Sexual Partners; D013636:Tanzania / Q000453:epidemiology; D014958:Wuchereria bancrofti / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000947:Antigens, Helminth