Hepatitis C virus remains a large health care burden to the world. Incidence rates across the world fluctuate and are difficult to calculate given the asymptomatic, often latent nature of the disease prior to clinical presentation. Prevalence rates across the world have changed as well with more countries aware of transfusion-related hepatitis C and more and more evidence supporting intravenous drug use as the leading risk factor of spread of the virus. This article reviews current hepatitis C virus prevalence and genotype data and examines the different risk factors associated with the virus.

The testing of dried blood spots (DBSs) for the presence of human immunodeficiency type 1 (HIV-1) proviral DNA by PCR was first described in 1991. The technology has proven to be particularly valuable for resolving the infection status in HIV-1-indeterminate infants born to HIV-1-seropositive mothers. To broaden the applicability of DBS PCR, we adapted it to a standardized, commercially available microwell plate amplification and detection kit, Amplicor HIV-1, produced by Roche Diagnostic Systems. The microwell assay is rapid and easy to perform and uses equipment that is readily available in routine diagnostic laboratories. The high level of performance of the assay was demonstrated in 1,168 duplicate tests performed on 584 DBSs from 178 uninfected and 100 HIV-1-infected individuals, including 56 children with perinatally acquired HIV-1. Of 12 infants who were followed prospectively from birth, 3 (25%) were infected in utero (PCR positive at birth) and 9 (75%) were infected intrapartum (PCR negative, culture negative at birth). Overall, HIV-1 DNA was identified in 3 of 11 (27.3%) DBSs collected from infected infants during the first 4 days of life, 8 of 9 (88.9o) DBSs collected between 10 and 15 days postpartum, and 166 of 167 (99.4%) DBSs collected after 15 days of age. All 320 DBSs from uninfected children were PCR DNA negative. These findings indicate that use of the Roche microwell DBS PCR assay provides a powerful new approach for large-scale perinatal screening programs and population-based studies of vertical transmission.