Preliminary data for genotype distribution and epidemiological aspects of hepatitis C virus infection in blood donors from Yucatan, Mexico

As a part of ongoing research on hepatitis C virus (HCV) frequency and infection in Yucatan, Mexico, we have been generating substantial quantities of data. In this communication, we present a portion of these data that are salient and of potential interest. Blood transfusion and surgery have been reported as the main cause of HCV infection in chronic hepatitis patients in Mexico (Vera de Leon et al., 2005). Substantial progress has been made in reducing HCV transmission risk from blood components through introduction of high-sensitivity screening tests that detect HCV antibodies (anti-HCV), but HCV infection still remains a major problem. This is primarily because of donations made during the window period. In an effort to shorten this window period and to increase blood and blood product safety, countries such as Germany have implemented HCV nucleic acid amplification testing as a routine screening test for blood donors (Hitzler & Runkel, 2001). Prevalence of HCV in the general population of Mexico is unknown, as is the incidence of HCV infection by blood transfusion. Data available to date are mostly based on presence of anti-HCV in blood donors and indicate a prevalence of approximately 0 7% (Alvarez-Muñoz et al., 2001; Ladron-deGuevara et al., 2002). Routine screening forHCVRNA in blood donors is not mandatory practice in Mexico, and therefore, the percentage of anti-HCV-reactive blood donors with viraemia is not known. Data on HCV genotype are consequently limited. As a part of an effort to generate genotype data to aid inHCV therapy and epidemiological studies, we determined HCV genotype distribution and any possible associations with age, sex and/or risk factors in a population of blood donors in Yucatan, Mexico. Between June 2005 and June 2006, blood samples were taken from 15 869 donors at the Central Blood Bank of the Ignacio Garcia Tellez National Medical Center, in Merida, Yucatan, Mexico. Serum samples were tested for anti-HCV antibodies using commercial Microparticle Enzyme Immunoassays (AxSYM HCV version3.0;AbbottLaboratories,Wiesbaden,Germany) following the manufacturer s instructions. Each donor gave informed consent at the time of blood donation, and the institution s Ethics Committee approved the study. Alanine amino transferase (ALT) levels in serum were determined with an automated Dimension RXL (Dade Behring, Inc., Newark, DE,USA) following the manufacturer s instructions. Reverse transcription–polymerase chain reaction (RT-PCR) and nested PCR analyses were used to test all the anti-HCV blood samples reactive for the presence ofHCVRNAusing a primer set that amplifies a highly conserved 5# untranslated region of the HCV genome (Bukh et al., 1992). F285 (5#-ACTGTCTTCACGCAGAAAGCGTCTAGCCAT-3#) and R14 (5#CGAGACCTCCCGGGGCACTCGCAAGCACCC-3#) were used as outer primers and F276 (5#-ACGCAGAAAGCGTCTAGCCATGGCGTTAGT-3#) and R21 (5#-TCCCGGGGCACTCGCAAGCACCCTATCAGG-3#) as inner primers. Serum samples from blood donors negative for anti-HCV and RNA-free reagents were used as negative controls. Positive controls were blood samples from patients with chronic HCV infection (i.e. with detectable anti-HCV and HCV RNA). The lower detection limit for the nested RT-PCR assay was established by serial 1 : 2 dilutions of serum from a patient with chronic HCV infection, whose HCV RNA level (1 215 000 copies mL) was measured quantitatively by PCR (Cobas Amplicor HCV monitor version 2.0; Roche Molecular Systems, Inc., Branchburg, NJ, USA). Detection limit for the nested RT-PCR assay was approximately 300 copies mL. Positive and negative controls were included in both amplification rounds. A sample was considered positive when repeatedly found positive after amplification of newly extracted material. Genotypes were determined using amplification of the core region with specific primers, which allowed Correspondence: BeatrizMarı́aGarcı́a-Montalvo,Calle19No.430x50, Fracc. Jardines de Mérida, 97135 Merida, Yucatan, Mexico. Tel. : 152 (999) 943-61-36; fax: 152 (999) 943-22-84; e-mail: bgarciam04@yahoo.com. mx