We conducted a phylogenetic analysis of 19 hepatitis B virus strains from Laos that belonged to 2 subgenotypes of a new genotype I. This emerging new genotype likely developed outside Southeast Asia and is now found in mixed infections and in recombinations with local strains in a geographically confi ned region.A s a result of mutations and recombinations, hepatitis B virus (HBV) has evolved into 8 known genotypes (A-H), with a putative new genotype I recently found in Asia (1,2). Some genotypes have been associated with distinct clinical patterns, and their detection and identifi cation are important for virus and disease surveillance.In Laos, 8.7% of the population are chronically infected with HBV, and perinatal transmission is the most common route of infection. Here, we present the phylogenetic analysis of 19 related strains found in voluntary blood donors from Laos that cluster with the new genotype I. The StudyPhylogenetic analysis of sequences obtained from hepatitis B surface antigen-positive fi rst-time blood donors from donation centers in Vientiane City and central provinces of Laos showed that 163 (42.2%) strains were of genotype B, and 204 (55.4%) were of genotype C. Subgenotypes included B2 (18), B3 (1), B4 (128), and B5 (16), as well as C2 (190), C3 (1), and C5 (13) ( Figure 1, panel A). Nineteen strains, including 15 complete sequences, did not group with any of the known genotypes A-H. These sequences formed 2 clusters, which were emerging from a common node (bootstrap value of 100%; Figure 1, panel A). One of the clusters grouped with a recently reported single strain from Vietnam, for which we had previously defi ned a new genotype I (2). The 2 new groups from Laos will be referred to here as subgenotypes I1 and I2. Notably, all I1 strains were of serotype adw, whereas all I2 subgenotypes were of serotype ayw. With 1 exception, all genotype I strains were found in donors living in Vientiane City. Strains recovered from Hanoi, Vietnam, 8 years ago and reported as aberrant strains (3) also group with subgenotype I1.Detailed analysis of full genome sequences showed that genotype C strains as a group were most closely related to genotype I (average Kimura distance of 7.89%, Table 1). The closest subgenotype was C3 with a 7.0% average Kimura distance (data not shown). The bootstrap value of the separating node was 92% (Figure 1, panel A), which is well above the bootstrap value of the G/DE node. On the S gene level, genotype I was most closely related to genotype G with a distance of 4.23% and a bootstrap value of 96% at the separating node (data not shown). Within the 2 subgenotypes I1 and I2, an average diversity over the complete genome of 1.19% and 0.94% was calculated; this difference increased to 2.33% when all strains were considered as a single group. The maximal genetic distance between 2 full-length genotype I strains was 4.3%. All clusterEmerging Infectious Diseases • www

BackgroundDespite hepatitis B vaccination at birth and at 6, 10 and 14 weeks of age, hepatitis B virus (HBV) infection continues to be endemic in the Lao People’s Democratic Republic (PDR). We carried out a cross-sectional serological study in infants, pre-school children, school pupils and pregnant women to determine their burden of disease, risk of infection and vaccination status.MethodsA total of 2471 participants between 9 months and 46 years old were recruited from urban (Vientiane Capital, Luang Prabang), semi-urban (Boulhikhamxai and Savannakhet) and remote rural areas (Huaphan). All sera were tested for anti-HBs and anti-HBc. Sera testing positive for anti-HBc alone were further tested for the presence of HBsAg.ResultsA low prevalence of HBsAg (0.5%) was detected among infants from Vientiane and Luang Prabang, indicating some success of the vaccination policy. However, only 65.6% had protective anti-HBs antibodies, suggesting that vaccination coverage or responses remain sub-optimal, even in these urban populations.In pre-school children from remote areas in Huaphan, 21.2% were positive for anti-HBc antibodies, and 4.6% were for HBsAg positive, showing that a significant proportion of children in these rural regions have early exposure to HBV. In pre-school children with 3 documented HBV vaccinations, only 17.0% (15/55) were serologically protected.Among school-children from semi-urban regions of Luang Prabang, Boulhikhamxai and Savannakhet provinces, those below the age of 9 who were born after HBV vaccine introduction had anti-HBc and HBsAg prevalence of 11.7% and 4.1%, respectively. The prevalence increased to 19.4% and 7.8% of 10–14 year olds and to 27% and 10.2% of 15–19 year olds.Pregnant women from Luang Prabang and Vientiane had very high anti-HBc and HBsAg prevalence (49.5% and 8.2%), indicating high exposure and risk of onward vertical transmission to the unborn infant.ConclusionsOverall, the results demonstrate a dramatic deficiency in vaccination coverage and vaccine responses and/or documentation within the regions of Lao PDR studied, which included urbanized areas with better health care access. Timely and effective hepatitis B vaccination coverage is needed in Lao PDR.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-457) contains supplementary material, which is available to authorized users.

In Lao People's Democratic Republic, a sizable proportion of HBsAg-negative and anti-HBc antibody-positive blood donations are potentially DNA positive and infective for hepatitis B.

The highest frequency of penile cancer occurs in Asia, Africa, and Latin America, and there have been a few reports concerning the association of penile cancer with human papillomavirus (HPV) infection in these areas. The objective of this study was to determine the relation between penile cancer and the prevalence of HPV genotypes in northern Thailand. Eighty-eight specimens of penile tissue (65 malignant, 1 pre-malignant, and 22 benign cases) were examined to determine the association of HPV infection. An in situ hybridization (ISH) method was used to detect and localize HPV-DNA. Sensitive HPV polymerase chain reaction (PCR) procedure was used for detection of HPV-DNA, and DNA sequencing was used to identify the HPV genotype. HPV-DNA was detected in 53.8% and 81.5% of cases of penile cancer, using ISH and PCR, respectively. The high-risk HPV-16, most commonly associated with penile cancer in previous reports, was found in only one case in this study. The most prevalent genotype was the high-risk HPV-18, found in 55.4% of the cases (32.3% single and 23.1% multiple infection) followed by the low-risk HPV-6, found in 43.1% of the cases (24.6% single and 18.5% multiple infection). In this study, penile cancer was found to be highly correlated with HPV-DNA. Specifically, infection with both the low-risk HPV-6 and the high-risk HPV-18 is the characteristic prevalence of HPV genotypes in penile cancer in this area.

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