Chromosome-level genome assembly of the Muscovy duck provides insight into fatty liver susceptibility

The Muscovy duck (Cairina moschata) is an economically important poultry species, which is susceptible to fatty liver. Thus, the Muscovy duck may serve as an excellent candidate animal model of non-alcoholic fatty liver disease. However, the mechanisms underlying fatty liver development in this species are poorly understood. In this study, we report a chromosome-level genome assembly of the Muscovy duck, with a contig N50 of 11.8 Mb and scaffold N50 of 83.16 Mb. The susceptibility of Muscovy duck to fatty liver was mainly attributed to weak lipid catabolism capabilities (fatty acid β-oxidation and lipolysis). Furthermore, conserved noncoding elements (CNEs) showing accelerated evolution contributed to fatty liver formation by down-regulating the expression of genes involved in hepatic lipid catabolism. We propose that the susceptibility of Muscovy duck to fatty liver is an evolutionary by-product. In conclusion, this study revealed the potential mechanisms underlying the susceptibility of Muscovy duck to fatty liver.

Mutations in the 'a' determinant of hepatitis B surface antigen among Chinese infants receiving active postexposure hepatitis B immunization

Twenty-four infants who became positive to the surface antigen of hepatitis B virus (HBsAg) despite a complete course of active postexposure immunization with plasma derived hepatitis B vaccine were studied. The polymerase chain reaction amplified products of the common neutralizing epitope 'a' determinant of HBsAg (Nucleotide 419-598) from serum samples were sequenced and analyzed for nucleotide mutations. Four cases (16.7%) had mutations that led to amino acid substitutions between codons 124 and 147. Only one case (N1) showed a substitution at codon 145 (from glycine to arginine, 145R), the other three were at codons 126-129. The mother of N1 was co-infected with the wild type and the mutant virus. Five years later, serum of N1 showed only the wild type virus. There was no significant relationship between the mutation rate and the anti-HBs response to hepatitis B vaccination. Results suggest that without immune selective pressure, 145R variant was not frequently observed, and was not stable. Mutation in the 'a' determinant was not an important cause of failure to prevent maternal-infant transmission of HBV by active postexposure hepatitis B immunization in Chinese children.

Long-term efficacy of active postexposure immunization of infants for prevention of hepatitis B virus infection. United States-People's Republic of China Study Group on Hepatitis B

Perinatal transmission of hepatitis B virus (HBV) contributes to the high prevalence of chronic infection in China and many other countries. In a placebo-controlled trial among 166 infants, the 12-month efficacy of active postexposure prophylaxis to prevent chronic perinatal HBV infection varied by vaccine (range, 45%-89%). In a 5-year follow-up study, 2 additional infants became chronically infected with HBV, and the efficacy of active prophylaxis was estimated to be 38% and 72% for the two vaccines at 5 years. In addition, 80% of immunized infants continued to have protective levels of antibody at the end of 5 years. However, among 27 infants who received passive-active immunoprophylaxis with high-dose hepatitis B immune globulin, only 60% (11/19) had protective antibody levels. These data indicate that active postexposure immunization initiated soon after birth continues to provide protection during early childhood when there is a high risk of chronic HBV infection.

Long-term immunogenicity and efficacy of recombinant yeast derived hepatitis B vaccine for interruption of mother-infant transmission of hepatitis B virus

Recombinant DNA Yeast-Derived Hepatitis B Vaccine (RYHB vaccine) is comparable to and can replace Plasma-Derived Hepatitis B Vaccine (PHB vaccine) for the prevention of mother-infant transmission of hepatitis B virus (HBV), but the duration of immune efficacy of RYHB vaccine is not clear. This study indicates the long-term efficacy for the prevention of mother-infant transmission of HBV. One hundred and six neonates born to HBsAg-carrier mothers with HBeAg positive were randomly divided into two groups, one receiving 20 micrograms per dose of RYHB vaccine and the another receiving 20 micrograms per dose of PHB vaccine on the day of birth, at 1 month and at 6 months (three times). Physical examination and blood tests were performed for all infants at 6, 12, 24, 36, 48 and 60 months of age. The results showed that the protective efficacies at 6, 12, 24, 36, 48 and 60 months were 67%, 75%, 63%, 62%, 57% and 56%, respectively for the RYHB vaccine group and 58%, 76%, 51%, 41%, 24% and 18%, respectively for the PHB vaccine group. The protective efficacy was notably significant in the last two years. The study indicates that the duration of protective efficacy is over 5 years with RYHB vaccine, being longer than that of PHB vaccine. These recipients of RYHB vaccine showed no side effects, and the vaccine is regarded as safe and effective.

A six-year survey of immunogenicity and efficacy of hepatitis B vaccine in infants born to HBsAg carriers

Although the efficacy of hepatitis B vaccine is well documented, the duration of immunity of healthy infants after vaccination is unknown. 99 infants born to hepatitis B surface antigen (HBsAg)-carrier mothers were studied and found to have positive anti-HBs (titer: greater than or equal to 10 mIU/mL) after a first injection of vaccine at the ages of 1 to 6 years. The infants were randomly divided into four groups of recipients treated with the vaccine of the National Institute of Allergy and Infectious Diseases (NIAID), U.S.A. or that of the Beijing Biological Products Research Institute (BBPRI), BBPRI vaccine in combination with hepatitis B immune globulin (HBIG) and placebo. The results showed that the protective efficacy dropped considerably after 5 years with NIAID vaccine, after 3 years with BBPRI vaccine and after 4 years with BBPRI vaccine plus HBIG. This suggests that a booster injection is needed 5 years after the first injection of NIAID vaccine, 3 years after BBPRI vaccine, and 4 years after BBPRI vaccine plus HBIG.

The affinity of anti-HBc antibodies in acute and chronic hepatitis B infection

Antibodies to hepatitis B core antigen (anti-HBc) are found in the sera of all individuals infected with hepatitis B virus. A role for these antibodies has been suggested in determining the outcome of infection. In this study, the affinity of anti-HBc antibodies in asymptomatic virus carriers was compared with that of antibodies present in the sera of patients with chronic liver disease. Persistently infected individuals with no evidence of clinical disease were found to have anti-HBc antibodies of greater affinity, compared with the chronic liver disease group. Sera from patients with chronic hepatitis contained high levels of low-affinity antibody whereas antibody levels in asymptomatic carriers were significantly lower. These findings are discussed in relation to the predicted role of anti-HBc antibodies in mediating hepatitis B virus-related hepatocellular injury.

Seroepidemiology of adult diarrhea rotavirus in China, 1977 to 1987

In 1982, large outbreaks of diarrhea that were caused by group B adult diarrhea rotavirus (ADRV) occurred throughout the People's Republic of China. Until 1982, group B rotavirus had never been associated with disease in humans. To determine whether ADRV was a new virus introduced in 1982 or had been present before that time, we examined antibody titers of ADRV in gamma globulin (pooled immunoglobulin) pools that were prepared during 1977 to 1987 in four cities in the People's Republic of China (Shanghai, Lanzhou, Wuhan, and Chandu). ADRV antibodies were assayed by using a blocking enzyme-linked immunosorbent assay. Antibodies were present in most Chinese gamma globulins tested, including those collected in Shanghai before the 1982 epidemic, and absent from American reference pools. The highest titers of antibody to ADRV (3,200) were found in gamma globulins collected in 1983 in Shanghai just after the epidemic, and these were fourfold higher than titers present in the preceding years. The quality of the gamma globulins stored for up to 12 years was tested by measuring levels of immunoglobulin G to group A rotavirus; these were equally high in gamma globulin pools prepared in the United States and in all samples from the People's Republic of China. Serum samples from patients from an outbreak of ADRV had elevated titers to ADRV 3 and 16 months after the onset of symptoms. These findings, as well as other epidemiologic findings on ADRV, suggest that the organism is an important and continuing cause of diarrhea in the People's Republic of China, was present before the first epidemic in 1982, and represents a risk to surrounding populations in Asia.

Prevention of perinatal acquisition of hepatitis B virus carriage using vaccine: preliminary report of a randomized, double-blind placebo-controlled and comparative trial

Hepatitis B is a serious disease of global significance. In developing countries, hepatitis B virus (HBV) infection and its sequelae rank among the public health problems of highest priority. Infants born to mothers who are chronic carriers of HBV are at particularly high risk of acquiring infection and becoming chronic HBV carriers. The efficacy of hepatitis B vaccine alone in preventing the transmission of HBV to infants born to HBV carrier mothers was determined in a double-blind placebo-controlled trial. Infants received plasma-derived vaccine at birth, 1 month, and 6 months of age. Of 180 infants born to hepatitis B surface antigen (HBsAg)-positive mothers, equal numbers received National Institute of Allergy and Infectious Disease (NIAID) vaccine, Beijing Institute of Vaccine and Serum (BIVS) vaccine, and placebo. The cumulative seroconversion to the vaccines at 1 year of age was 95% and 75%, respectively. Vaccine efficacy as measured by the prevention of HBsAg-positive events was 88% for the NIAID vaccine and 51% for the BIVS vaccine. Vaccine efficacy was similar among infants born to hepatitis Be antigen-positive mothers. Because of the low efficacy of the BIVS vaccine, an additional group of 28 infants was given vaccine and hepatitis B immune globulin at birth. The resulting efficacy was 83%. The results of this trial indicate that hepatitis B vaccine alone can substantially reduce perinatally acquired HBV infection and the resulting chronic carrier state.