The prevalence study and the characterization of hepatitis C virus (HCV) have been carried out in the Philippines and the sequence determination of 5'-untranslated region (5'-UTR)-Core and NS5B regions of HCV was performed in this study. An HCV strain (SE-03-07-1689) collected in Metro Manila, Philippines, belonged to discordant subtypes, 2b and 1b in 5'-UTR-Core and NS5B regions, respectively. The 9.3kb-sequence of this strain including the entire open reading frame were compared with those of the reference strains retrieved from the HCV sequences database (GenBank/EMBL/DDBJ) and indicated a recombination event.The computation of the sequence similarity mapped a crossover point within NS3region. This is the second report on the inter-genotype recombinant of HCV and the third one when an intra-genotype recombinant is included. This recombinant strain, SE-03-07-1689, is tentatively designated as RF3_2b/1b according to the suggestions used for other two HCV recombinants.

From 2002 to 2007, 1,590 individuals were enrolled in an active surveillance program conducted in Metro Cebu, Philippines, where the anti-HCV-positive rate was significantly and constantly high among injecting drug users (83%, 793/960; 71-88%), especially among those living in downtown (89%, 683/770; 87-100%), despite the extremely low percentage of anti-HIV-positives (0.34%, 3/874). Sampling areas were then enlarged nationwide and the number of samples increased to 2,645 at the end of 2007. A total of 444 samples were positive for HCV RNA. Phylogenetic analysis based on NS5B and E1-E2 regions revealed that the most dominant HCV subtype was 1a, and followed by 2b, 2a, and 1b, and that the HCV strains had the largest variety in Metro Manila and its vicinity (P < 0.01). Interestingly, subtype 1b was detected solely in Metro Manila, and four HCV strains collected in this area showed higher homology to specific foreign strains retrieved from the Genbank/EMBL/DDBJ database with bootstrap values of 68-95% comparing with other strains analyzed in this nationwide study. These data suggest that HCV strains may be introduced occasionally into the Philippines possibly through Metro Manila as a main entry point. Considering the fact that an HIV epidemic started primarily via contaminated needle sharing in Asia, the constantly high rate of HCV infections and the newly introduced foreign HCV strains in the absence of HIV epidemic warrant further investigation on HCV entry and spread for early detection of an HIV epidemic in the Philippines.

No abstract

Human immunodeficiency virus (HIV) sentinel surveillance program for injecting drug users has been conducted in Metro Cebu, the Philippines. A low prevalence (0-0.52%) of anti-HIV-positivity had been detected in this population from 2002 to 2007. However, a 10-fold increase in HIV prevalence was detected in the 2009 national HIV sentinel surveillance program. It prompted an additional outreach program to be conducted in Metro Cebu in January 2010, which recorded the highest HIV prevalence rate ever documented in the Philippines (75%, 44/59). HIV genes from fourteen 2009 to 2010 Metro Cebu strains were clustered closely in the phylogenetic tree, but no other strain collected outside Metro Cebu and none stored in the International Nucleotide Sequence Database was allocated to the same phylogenetic cluster. All these HIV infections have emerged in the anti-hepatitis C virus (HCV)-positive population (100%, 62/62) in Metro Cebu from 2009 to 2010. The five HCV strains from the individuals harboring the closely related HIV strains were categorized into different subtypes. These results strongly suggest that HIV infections occurred recently and spread rapidly among injecting drug users, while HCV had been circulating previously among them. Considering the fact that injecting drug use was the first mode of HIV transmission in Asia, extensive monitoring of injecting drug users and associated bridging populations is necessary. Therefore, HCV-guided characterization of the spread of HIV to populations that are vulnerable to blood-borne infections could play an important role in alerting health authorities to the early phase of an HIV epidemic.

This study conducted on a limited number of patients demonstrates the potential efficacy of oromucosal IFN-alpha-n1 [INS] in chronic HBV infection with therapeutic benefit equal to parenterally administered interferon alpha (IFNalpha) but without the side effects of myelosuppresion. Owing to the small population studied, we are unable to extrapolate these findings to the general population of patients with chronic HBV infection. A large-scale study is needed to confirm these findings.