title: Human Immunodeficiency Virus, Antiretroviral Therapy and Markers of Lymphatic Filariasis Infection: A Cross-sectional Study in Rural Northern Malawi.
abstract: BACKGROUND
  Lymphatic filariasis (LF) and human immunodeficiency virus (HIV) are major public health problems. Individuals may be co-infected, raising the possibility of important interactions between these two pathogens with consequences for LF elimination through annual mass drug administration (MDA).
  
  
  RESULTS
  We analysed circulating filarial antigenaemia (CFA) by HIV infection status among adults in two sites in northern Malawi, a region endemic for both LF and HIV. Stored blood samples and data from two geographically separate studies were used: one a recruitment phase of a clinical trial of anti-filarial agent dosing regimens, and the other a whole population annual HIV sero-survey. In study one, 1,851 consecutive adult volunteers were screened for HIV and LF infection. CFA prevalence was 25.4% (43/169) in HIV-positive and 23.6% (351/1487) in HIV-negative participants (p=0.57). Geometric mean CFA concentrations were 859 and 1660 antigen units per ml of blood (Ag/ml) respectively, geometric mean ratio (GMR) 0.85, 95%CI 0.49-1.50. In 7,863 adults in study two, CFA prevalence was 20.9% (86/411) in HIV-positive and 24.0% (1789/7452) in HIV-negative participants (p=0.15). Geometric mean CFA concentrations were 630 and 839 Ag/ml respectively (GMR 0.75, 95%CI 0.60-0.94). In the HIV-positive group, antiretroviral therapy (ART) use was associated with a lower CFA prevalence, 12.7% (18/142) vs. 25.3% (67/265), (OR 0.43, 95%CI 0.24-0.76). Prevalence of CFA decreased with duration of ART use, 15.2% 0-1 year (n=59), 13.6% >1-2 years (n=44), 10.0% >2-3 years (n=30) and 0% >3-4 years treatment (n=9), p<0.01 χ2 for linear trend.
  
  
  CONCLUSIONS
  In this large cross-sectional study of two distinct LF-exposed populations, there is no evidence that HIV infection has an impact on LF epidemiology that will interfere with LF control measures. A significant association of ART use with lower CFA prevalence merits further investigation to understand this apparent beneficial impact of ART.
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Terence
authors.initials: T
authors.lastname: Tafatatha
authors.affiliation: Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: Miriam
authors.initials: M
authors.lastname: Taegtmeyer
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Bagrey
authors.initials: B
authors.lastname: Ngwira
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi.
authors.forename: Amos
authors.initials: A
authors.lastname: Phiri
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi.
authors.forename: Mariot
authors.initials: M
authors.lastname: Kondowe
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi.
authors.forename: Wilson
authors.initials: W
authors.lastname: Piston
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Molesworth
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi.
authors.forename: Ndoliwe
authors.initials: N
authors.lastname: Kayuni
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Olivier
authors.initials: O
authors.lastname: Koole
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Amelia
authors.initials: A
authors.lastname: Crampin
authors.affiliation: Tropical Projects, Hitchin, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Horton
authors.affiliation: Karonga Prevention Study, Karonga District, Malawi; Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Neil
authors.initials: N
authors.lastname: French
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D000947:Antigens, Helminth / Q000097:blood; D060085:Coinfection / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D004605:Elephantiasis, Filarial / Q000453:epidemiology*; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D008295:Malawi / Q000453:epidemiology; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data; D013997:Time Factors
chemical_list: D044966:Anti-Retroviral Agents; D000947:Antigens, Helminth