A specification of a population leading to an HIV epidemic in the Philippines, and modeling of the entry sites and the resultant circulation routes of foreign HIV strains into and in the country.

监测艾滋病毒感染对预防疫情非常重要。然而，仅通过HIV监测难以识别流行病的早期阶段，我们增加了丙型肝炎病毒（HCV）的监测，以用作血源性IIN感染的替代标志物。经血液传播的艾滋病病毒感染被认为是在性接触相关感染之前爆发的初始阶段的传播措施，菲律宾在吕宋岛、维萨亚岛和棉兰老岛组织了监测区，共检测了2,645份样本，其中包括1,494份来自注射毒品使用者的样本。艾滋病毒很少被发现，这支持了菲律宾艾滋病毒感染率低的事实。然而，经血液传播的HCV感染在静脉吸毒者和透析患者中很普遍。宿务市中心注射吸毒者中HCV感染率为8936%，HIV感染率为0.40%。HCV基因分型结果显示，大马尼拉（菲律宾首都和吕宋岛中心）流行株的种类最多，亚型1b，基因型4和6仅见于大马尼拉，部分毒株与国外毒株的同源性高于大马尼拉流行株。菌株多样性表明外来菌株可能优先进入大马尼拉。在系统发育树中，从上述三个地区采集的一些毒株混合在一起，提示HCV毒株可能在菲律宾快速传播，HCV研究结果表明，WV可能进入大马尼拉，并在菲律宾其他地区传播。

The monitoring of an HIV infection is important for the prevention of an outbreak. However, it is difficult to identify the early phase of an epidemic only by HIV monitoring and we add the monitoring of Hepatitis C virus (HCV) to be used for a surrogate marker of blood-borne IIN infection. Blood-borne HIV infections have been considered to be the spread measures at initial phase of an outbreak before sexual contact-related infections.Surveillance areas have been organized in Luzon, Visaya, and Mindanao in the Philippines, and totally 2,645 samples have been tested including 1,494 ones from injecting drug users (IDUs). HIV has been rarely detected, which supports the low prevalence of HIV infection in the Philippines. However, the blood-borne HCV infections are prevalent among IDUs and dialysis patients. The percentage of HCV infections among IDUs at downtown in Metro Cebu (the center of Visaya) were 8936 although that of HIV was few, 0.40%. The profiles of HCV indicated that the variety of the strains prevalent in Metro Manila (capital of the Philippines and the center of Luzon) has been biggest Subtype-1b, genotype-4 and 6 were only observed in Metro Manila Moreover, some of them strains bad higher homology to foreign strains than those prevalent in Metro Manila. The strains variety may indicate that the foreign strains may preferentially enter into Metro Manila than other areas. Some strains collected in three areas (shown above) mixed together in the Phylogenetic trees, suggesting HCV stains may circulate quickly in the Philippines.The results of HCV study indicate that WV may enter into Metro Manila and circulate into other area in the Philippines.