Occult hepatitis B infections among blood donors in Lao PDR.

BACKGROUND AND OBJECTIVES: In Lao People's Democratic Republic, hepatitis B virus is highly endemic. However, blood donations are only screened for HBsAg, leaving a risk of transmission by HBsAg-negative occult infected donors. Here, we characterized first-time blood donors to assess prevalence of hepatitis B virus infections and occult infected donors. MATERIALS AND METHODS: Sera were screened for HBsAg, HBeAg and anti-HBs, anti-HBc and anti-HBe antibodies. Occult HBV infections (OBIs) were assessed in HBsAg-negative sera by PCR, and sera of HBsAg positive and occult infected donors were phylogenetically characterized. RESULTS: 9·6% of the donors were HBsAg positive, and 45.5% were positive for at least one of the hepatitis B virus serum markers. More than 40% HBsAg carriers were HBeAg positive, with HBeAg seroconversion occurring around 30 years of age. Furthermore, 10·9% of HBsAg-negative, anti-HBc and/or anti-HBs-positive donors were occult infected with hepatitis B virus. Thus, at least 3·9% of blood donations would potentially be unsafe, but hepatitis B virus DNA copy numbers greatly varied between donors. CONCLUSION: 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.

Blood group antigen distribution in Lao blood donors.

Blood group antigens can be distributed differently within different nationalities. Therefore, information about the prevalence of blood group antigens in the Lao population will be useful for providing better blood transfusion services in the Lao People's Democratic Republic. The purpose of this study was to determine the prevalence of blood group antigens in Lao blood donors. Blood samples from 464 Lao national volunteer blood donors were typed for antigens in various blood group systems including ABO, MNS, P1PK, Rh, Kell, Lewis, Duffy, Kidd, and Diego. The results show similar antigen prevalence to that among Northeast Thais for ABO, MNS, P1PK, Rh, Kell, and Duffy systems. In the ABO system, 0 was the highest at 37.72 percent,followed by 35.56 percent B, 19.83 percent A1, 6.47 percent A1B,and 0.43 percent A2B. The common phenotypes were D+C+E-ce+at 60.43 percent, M+N-S-s+ at 46.55 percent, Fy(a+b-) at 80.82 percent, Jk(a+b+) at 39.44 percent, and kk at 99.72 percent.Interestingly, Le(a-b-) was found at 50.43 percent, which was significantly higher than previous reports in Thais and Taiwanese.The P1 antigen was found in only 18.97 percent, which is much lower than in Whites and Blacks. Rare phenotypes were Fy(a-b+)and Jk(a-b-), found at 0.22 percent and 4.31 percent, respectively.In terms of negative antigens the study shows 0.22 percent Fy(a-), 35.34 percent Jk(a-), 29.53 percent Jk(b-), 3.04 percent C-, 2.39 percent e-, and 5.17 percent M-. The high prevalence of C, e, and Fy" and immunogenicity of these antigens may induce alloimmunization in transfusion-dependent patients, creating difficulties providing blood from Lao donors. The information obtained from this study will be useful for improving transfusion therapy in the country, especially for estimation of the availability of compatible blood for patients who have produced antibodies.

High genetic diversity including potential new subtypes of hepatitis C virus genotype 6 in Lao People's Democratic Republic.

Sera from 105 anti-HCV-positive first-time blood donors collected in 2004, 2005 and 2008 in different provinces in Laos were investigated by PCR. Forty-five samples were positive for HCV (42.86%); two belonged to subtype 1b (2/45, 4.4%) and all others to genotype 6 (43/45, 95.6%), including subtypes 6b, 6h, 6k, 6l, 6n and 6q. Three groups of sequences were not clearly attributable to any genotype 6 subtype, two of which may be regarded as candidates for new subtypes of genotype 6. Two samples were mixed infected with different subtypes or clusters of genotype 6 viruses.

Differences in ABO antibody levels among blood donors: a comparison between past and present Japanese, Laotian, and Thai populations.

Passively transfused blood group antibodies cause clinical problems. High titers of anti-A and anti-B seem to be one reason for hemolytic transfusion reactions and for ABO HDN. In Japan, anti-A and anti-B titers notably decreased in the 15 years between 1986 and 2001. At present, titers of more than 100,as measured using the saline method, are rare. Differences in the level of anti-A and anti-B among ethnic populations have been reported; these differences were found to be the result of environmental factors rather than hereditary factors. In the present study, the anti-A and anti-B titers of random donors in three Asian populations are compared. In Thailand, the IgM anti-A and anti-B titers are low and are similar to the Japanese titers reported in 2001, but the IgG anti-A and anti-B titers are high and are similar to the Japanese titers reported in 1986. In the Lao People's Democratic Republic, both the IgM and the IgG anti-A and anti-B titers are high and are similar to those reported in Japan in 1986. In addition, anti-A and anti-B titers of different sex donors and of various age groups were also compared. High titers were found in 8.8 percent of the female donors in the younger than 30 age group and in 36.7 percent of the female donors in the older than 50 age group.

Reproductive health in selected villages in Lao PDR.

The aim of the project was to improve the knowledge and attitude towards birth spacing by training the villagers in the selected villages of Vientiane Province in Lao PDR in family planning, providing them with the various family planning methods, and improving antenatal (ANC) and postnatal (PNC) care in the villages. Throughout the province, traditional birth attendants (TBA) were trained on several occasions during the project period. There were clear indications that reproductive health improved between 1995 and 1997. Considerable improvements were observed in the percentage of women making use of ANC and practising birth spacing by using some form of contraception or other. The most common methods used were contraceptive pills and injectables. In the case of child mortality a slight decrease was found in the percentage of women having their first pregnancy below the age of 18 years. A still unsolved problem is the high number of abortions.