title: Latent class analysis of human herpesvirus 8 assay performance and infection prevalence in sub-saharan Africa and Malta.
abstract: Human herpesvirus 8 (HHV-8) is thought to be highly prevalent in Mediterranean countries and sub-Saharan Africa, where it causes Kaposi's sarcoma in a small proportion of infected immunocompetent persons. However, the lack of serological tests with established accuracy has hindered our understanding of the prevalence, risk factors and natural history of HHV-8 infection. We tested 837 subjects from Congo, Botswana (mostly young adults) and Malta (elderly adults), using an immunofluorescence assay and 2 enzyme immunoassays (EIAs, to viral proteins K8.1 and orf65). Each assay found HHV-8 seroprevalence to be high (49-87%) in the African populations and generally lower (9-54%) in Malta. However, there was only modest agreement among tests regarding which subjects were seropositive (3-way kappa, 0.05-0.34). We used latent class analysis to model this lack of agreement, estimating each test's sensitivity and specificity and each population's HHV-8 prevalence. Using this approach, the K8.1 EIA had consistently high sensitivity (91-100%) and specificity (92-100%) across populations, suggesting that it might be useful for epidemiological studies. Compared with the K8.1 EIA, both the immunofluorescence assay and the orf65 EIA had more variable sensitivity (80-100% and 58-87%, respectively) and more variable specificity (57-100% and 48-85%, respectively). HHV-8 prevalence was 7% among elderly Maltese adults. Prevalence was much higher (82%) in Congo, consistent with very high Kaposi's sarcoma incidence there. Prevalence was also high in Botswana (87% in Sans, an indigenous group, and 76% in Bantus), though Kaposi's sarcoma is not common, suggesting that additional co-factors besides HHV-8 are needed for development of Kaposi's sarcoma.
authors.affiliation: Viral Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD 20852, USA. engelse@exchange.nih.gov
authors.forename: E A
authors.initials: EA
authors.lastname: Engels
authors.forename: M D
authors.initials: MD
authors.lastname: Sinclair
authors.forename: R J
authors.initials: RJ
authors.lastname: Biggar
authors.forename: D
authors.initials: D
authors.lastname: Whitby
authors.forename: P
authors.initials: P
authors.lastname: Ebbesen
authors.forename: J J
authors.initials: JJ
authors.lastname: Goedert
authors.forename: J L
authors.initials: JL
authors.lastname: Gastwirth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001902:Botswana / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D003223:Congo / Q000453:epidemiology; D005260:Female; D005455:Fluorescent Antibody Technique; D006566:Herpesviridae Infections / Q000453:epidemiology*; D019288:Herpesvirus 8, Human / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques; D015994:Incidence; D008297:Male; D008319:Malta / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D012514:Sarcoma, Kaposi / Q000453:epidemiology*; D012680:Sensitivity and Specificity; D014764:Viral Proteins / Q000032:analysis
chemical_list: C119019:ORF65 protein, human herpesvirus 8; D014764:Viral Proteins