title: Estimated Prevalence of Cryptococcus Antigenemia (CrAg) among HIV-Infected Adults with Advanced Immunosuppression in Namibia Justifies Routine Screening and Preemptive Treatment.
abstract: BACKGROUND
  Cryptococcal meningitis is common and associated with high mortality among HIV infected persons. The World Health Organization recommends that routine Cryptococcal antigen (CrAg) screening in ART-naïve adults with a CD4+ count <100 cells/μL followed by pre-emptive antifungal therapy for CrAg-positive patients be considered where CrAg prevalence is ≥3%. The prevalence of CrAg among HIV adults in Namibia is unknown. We estimated CrAg prevalence among HIV-infected adults receiving care in Namibia for the purpose of informing routine screening strategies.
  
  
  METHODS
  The study design was cross-sectional. De-identified plasma specimens collected for routine CD4+ testing from HIV-infected adults enrolled in HIV care at 181 public health facilities from November 2013 to January 2014 were identified at the national reference laboratory. Remnant plasma from specimens with CD4+ counts <200 cells/μL were sampled and tested for CrAg using the IMMY® Lateral Flow Assay. CrAg prevalence was estimated and assessed for associations with age, sex, and CD4+ count.
  
  
  RESULTS
  A total of 825 specimens were tested for CrAg. The median (IQR) age of patients from whom specimens were collected was 38 (32-46) years, 45.9% were female and 62.9% of the specimens had CD4 <100 cells/μL. CrAg prevalence was 3.3% overall and 3.9% and 2.3% among samples with CD4+ counts of CD4+<100 cells/μL and 100-200 cells/μL, respectively. CrAg positivity was significantly higher among patients with CD4+ cells/μL < 50 (7.2%, P = 0.001) relative to those with CD4 cells/μL 50-200 (2.2%).
  
  
  CONCLUSIONS
  This is the first study to estimate CrAg prevalence among HIV-infected patients in Namibia. CrAg prevalence of ≥3.0% among patients with CD4+<100 cells/μL justifies routine CrAg screening and preemptive treatment among HIV-infected in Namibia in line with WHO recommendations. Patients with CD4+<100 cells/μL have a significantly greater risk for CrAg positivity. Revised guidelines for ART in Namibia now recommend routine screening for CrAg.
authors.affiliation: Division of Global HIV/AIDS (DGHA), Centers for Disease Control and Prevention (CDC), Windhoek, Namibia.
authors.forename: Souleymane
authors.identifier: http://orcid.org/0000-0002-4206-4454
authors.initials: S
authors.lastname: Sawadogo
authors.affiliation: Namibia Institute of Pathology (NIP), Windhoek, Namibia.
authors.forename: Boniface
authors.initials: B
authors.lastname: Makumbi
authors.affiliation: Mycotic Disease Branch, Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America.
authors.forename: Anne
authors.initials: A
authors.lastname: Purfield
authors.affiliation: Namibia Institute of Pathology (NIP), Windhoek, Namibia.
authors.forename: Christophine
authors.initials: C
authors.lastname: Ndjavera
authors.affiliation: Division of Global HIV/AIDS (DGHA), Centers for Disease Control and Prevention (CDC), Windhoek, Namibia.
authors.forename: Gram
authors.initials: G
authors.lastname: Mutandi
authors.affiliation: Global Health Sciences, University of California San Francisco, San Francisco, CA, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Maher
authors.affiliation: Directorate of Special Programs, Ministry of Health and Social Services, Windhoek, Namibia.
authors.forename: Francina
authors.initials: F
authors.lastname: Kaindjee-Tjituka
authors.affiliation: Division of Global HIV/AIDS (DGHA), Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Kaplan
authors.affiliation: Mycotic Disease Branch, Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Park
authors.affiliation: Division of Global HIV/AIDS (DGHA), Centers for Disease Control and Prevention (CDC), Windhoek, Namibia.
authors.forename: David W
authors.initials: DW
authors.lastname: Lowrance
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000935:Antifungal Agents / Q000494:pharmacology*; D000946:Antigens, Fungal / Q000097:blood*; D003430:Cross-Sectional Studies; D003454:Cryptococcus / Q000187:drug effects* / Q000276:immunology / Q000502:physiology*; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology*; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009276:Namibia / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000935:Antifungal Agents; D000946:Antigens, Fungal