An enzyme-linked immunosorbent assay for the detection of canine antibodies to canine adenoviruses.

An enzyme-linked immunosorbent assay was used to detect canine immunoglobulin G antibodies specific for infectious canine hepatitis virus and the serologically related canine adenovirus Type 2. The sequential development of homologous and heterologous antibodies was measured by the enzyme-linked immunosorbent assay and serum neutralization tests in two groups of dogs which were experimentally infected with either infectious canine hepatitis virus or canine adenovirus Type 2. Both tests were comparable in their abilities to detect the development of homologous and heterologous antibodies. Homologous antibodies were detected earlier and to a higher titer in both tests. There was a 98% agreement between the serum neutralization test and the enzyme-linked immunosorbent assay when sera from 224 random-source dogs were examined for infectious canine hepatitis virus antibodies. The enzyme-linked immunosorbent assay was found to be a highly efficient and rapid test to determine the immune status of dogs to infectious canine hepatitis virus and canine adenovirus Type 2.     

Viricidal Effects of Lactobacillus and Yeast Fermentation

The survival of selected viruses in Lactobacillus- and yeast-fermented edible waste material was studied to determine the feasibility of using this material as a livestock feed ingredient. Five viruses, including Newcastle disease virus, infectious canine hepatitis virus, a porcine picornavirus, frog virus 3, and bovine virus diarrhea, were inoculated into a mixture of ground food waste (collected from a school lunch program) containing Lactobacillus acidophilus. Mixtures were incubated at 20, 30, and 40°C for 216 h. In a second trial, four viruses, including Newcastle disease virus, infectious canine hepatitis virus, frog virus 3, and a porcine picornavirus, were inoculated into similar edible waste material containing Saccharomyces cerevisiae. Mixtures were incubated at 20 and 30°C for 216 h. Samples were obtained daily for quantitative (trial 1) and qualitative (trial 2) virus isolation. Temperature, pH, and redox potential were monitored. Controlled pH and temperature studies were also done and compared with the inactivation rates in the fermentation processes. In trial 1 (Lactobacillus fermentation), infectious canine hepatitis virus survived the entire test period in the fermentation process but was inactivated below pH 4.5 in the controlled studies. Newcastle disease virus was inactivated by day 8 in the fermentation process and appeared to be primarily heat sensitive and secondarily pH sensitive in the controlled studies. The porcine picornavirus survived the fermentation process for 8 days at 20°C but was inactivated more rapidly at 30 and 40°C. The controlled studies verified these findings. Frog virus 3 was inactivated by day 3 in the fermentation process and appeared to be sensitive to low pH in the controlled studies. Bovine virus diarrhea was rapidly inactivated in the fermentation process (less than 2 h) and was pH and temperature sensitive. In trial 2 (yeast fermentation), infectious hepatitis virus survived the entire test period in the fermentation process. Newcastle disease virus was inactivated by day 7 at 20°C and day 6 at 30°C. The porcine picornavirus was inactivated by day 7 at 30°C but survived the entire test period at 20°C. Frog virus 3 was inactivated by day 3 at 20°C and day 2 at 30°C.     

Hepatitis B virus translocates across a trophoblastic barrier

Mother-infant transmission of hepatitis B virus (HBV) accounts for up to 30% of worldwide chronic infections. The mechanism and high-risk period of HBV transmission from mother to infant are unknown. Although largely prevented by neonatal vaccination, significant transmission continues to occur in high-risk populations. It is unclear whether HBV can traverse an intact epithelial barrier to infect a new host. Transplacental transmission of a number of viruses relies on transcytotic pathways across placental cells. We wished to determine whether infectious HBV can traverse a polarized trophoblast monolayer. We used a human placenta-derived cell line, BeWo, cultured on membranes as polarized monolayers, to model the maternal-fetal barrier. We assessed the effects of placental maturity and maternal immunoglobulin on viral transport. Intracellular viral trafficking pathways were investigated by confocal microscopy. Free HBV (and infectious duck hepatitis B virus) transcytosed across trophoblastic cells at a rate of 5% in 30 min. Viral transport occurred in microtubule-dependent endosomal vesicles. Additionally, confocal microscopy showed that the internalized virus traverses a monensin-sensitive endosomal compartment. Differentiation of the cytotrophoblasts to syncytiotrophoblasts resulted in a 25% reduction in viral transcytosis, suggesting that placental maturity may protect the fetus. Virus translocation was also reduced in the presence of HBV immunoglobulin. We show for the first time that transcytosis of infectious hepadnavirus can occur across a trophoblastic barrier early in gestation, with the risk of transmission being reduced by placental maturity and specific maternal antibody. This study suggests a mechanism by which mother-infant transmission may occur.     

TnBP?Triton X-45 Treatment of Plasma for Transfusion Efficiently Inactivates Hepatitis C Virus

Risk of transmission of hepatitis C virus (HCV) by clinical plasma remains high in countries with a high prevalence of hepatitis C, justifying the implementation of viral inactivation treatments. In this study, we assessed the extent of inactivation of HCV during minipool solvent/detergent (SD; 1% TnBP / 1% Triton X-45) treatment of human plasma. Luciferase-tagged infectious cell culture-derived HCV (HCVcc) particles were used to spike human plasma prior to treatment by SD at 31 ± 0.5°C for 30 min. Samples were taken before and after SD treatment and filtered on a Sep-Pak Plus C18 cartridge to remove the SD agents. Risk of cytotoxicity was assessed by XTT cell viability assay. Viral infectivity was analyzed based on the luciferase signals, 50% tissue culture infectious dose viral titer, and immunofluorescence staining for HCV NS5A protein. Total protein, cholesterol, and triglyceride contents were determined before and after SD treatment and C18 cartridge filtration. Binding analysis, using patient-derived HCV clinical isolates, was also examined to validate the efficacy of the inactivation by SD. SD treatment effectively inactivated HCVcc within 30 min, as demonstrated by the baseline level of reporter signals, total loss of viral infectivity, and absence of viral protein NS5A. SD specifically targeted HCV particles to render them inactive, with essentially no effect on plasma protein content and hemostatic function. More importantly, the efficacy of the SD inactivation method was confirmed against various genotypes of patient-derived HCV clinical isolates and against HCVcc infection of primary human hepatocytes. Therefore, treatment by 1% TnBP / 1% Triton X-45 at 31°C is highly efficient to inactivate HCV in plasma for transfusion, showing its capacity to enhance the safety of therapeutic plasma products. We propose that the methodology used here to study HCV infectivity can be valuable in the validation of viral inactivation and removal processes of human plasma-derived products.     

Hepatitis A Immunoglobulin: An International Collaborative Study to Establish the Second International Standard

A collaborative study was carried out to assess the suitability of a candidate replacement material for the International Standard for hepatitis A immunoglobulin, which was found to be reactive for HCV RNA, and to calibrate it in International Units. The candidate standard, coded 97/646, was derived from a bulk of 16% immunoglobulin supplied by the Central Laboratory of the Netherlands Red Cross, Amsterdam, and diluted 1 in 2 in H2O resulting in a final immunoglobulin concentration of 8%. Sixteen laboratories from 11 countries participated in the study and contributed data from 64 assays performed using six commercial assay kits and four in-house methods. All assays were analysed as parallel line bioassays comparing assay response with log concentration. The overall mean potency of the candidate replacement immunoglobulin standard, 97/646, relative to the International Standard for hepatitis A immunoglobulin, was 98.6 IU/ml. A freeze-dried serum preparation, 97/648, was also calibrated in this study and had a potency of 22.64 IU/ml. The Second International Standard for hepatitis A immunoglobulin, human, was established by the World Health Organisation Expert Committee on Biological Standardisation in 1998 with a potency of 49 IU per ampoule when reconstituted in 0.5 ml.     

Effect of the content of hepatitis A antibodies in immunoglobulin preparations on the effectiveness of the immunoglobulin prophylaxis of hepatitis A

The results of a strictly controlled experiment showed that prevention of hepatitis A by the injection of immunoglobulin with hepatitis A virus (HAV) antibody titer 1:10000 was 3 times as effective as that achieved with immunoglobulin containing HAV antibodies in titer 1:2500. It is recommended to determine the level of specific HAV antibodies in immunoglobulins and to use immunoglobulins with a high level of HAV antibodies for prevention of hepatitis A.     

Immunisation of neonates at high risk of hepatitis B in England and Wales: national surveillance.

The results of a voluntary programme of immunisation against hepatitis B in neonates at high risk (mother being positive for hepatitis B surface antigen and without hepatitis B e antibody or having had acute hepatitis B late in pregnancy) are reported. The programme was offered in England and Wales from November 1982. Passive immunisation alone was available in the first six months of life until 1985, after which infants received passive and active immunisation from birth; in addition, some infants received passive immunisation for six months followed by a course of hepatitis B vaccine. All but a few infants received the first immunising dose within 48 hours after birth. Blood samples for analysing markers of hepatitis B virus were available at 1 year from 147 of the 223 infants given passive immunisation, 54 of the 72 given passive followed by active immunisation, and 102 of the 155 given passive and active immunisation at birth. At 1 year 11 of the 127 (9%) infants given four or more doses of specific hepatitis B immunoglobulin were positive for hepatitis B surface antigen compared with four of the 20 given three or fewer doses; 11 had levels of hepatitis B surface antibody greater than 50 IU/l. Only one of the 54 infants given passive then active immunisation was positive for hepatitis B surface antigen at 1 year and four infants had low (less than or equal to 50 IU/l) levels of hepatitis B surface antibody. Four of the 102 infants who received passive and active immunisation at birth were positive for hepatitis B surface antigen. Two had received the fill course of vaccine, whereas in the other two vaccination was incomplete or unstated. In 79 of the 89 infants who received a complete course of vaccination the level of hepatitis B surface antibody was known, and 70 had levels at 1 year greater than 100 IU/1. Reactions to immunisation were not severe at any age. The incidence of side effects was 8% for the immunoglobulin, 11% for the vaccine, and 9% when immunoglobulin and vaccine were given together. Wider collaboration in the programme is requested.     

Detecting the presence of infectious hepatitis A virus in molluscs positive to RT-nested-PCR

AIMS: The objective of this study was to determine the presence of infectious hepatitis A virus (HAV) in molluscs naturally contaminated with viral HAV-RNA. METHODS AND RESULTS: One hundred and forty-two mollusc samples were analysed for the presence of viral HAV-RNA using RT-nested-PCR; positive samples were then analysed with an integrated method, cell-culture RT-PCR, to detect infectious virus. Viral HAV-RNA was detected in 34.5% of the samples while 12.7% of the total samples were positive for the presence of infectious virus. CONCLUSIONS: The results demonstrate the validity of the screening method (RT-nested-PCR) and the necessity of applying a method that is capable of detecting the presence of infectious HAV. SIGNIFICANCE AND IMPACT OF THE STUDY: The study demonstrates that in any case, to determine the safety for human consumption, the results of RT-nested-PCR must be confirmed with an integrated cell-culture PCR method.     

2004—2013年深圳市乙型病毒性肝炎流行特征分析

目的了解深圳市乙型病毒性肝炎(乙肝)流行特征,为制定乙肝防控策略提供科学依据。方法用描述性流行病学方法对2004—2013年深圳市乙肝疫情资料进行分析。结果深圳市2004—2013年共报告乙肝病例90 292例,剔除慢性病例71 435例,年均报告发病率为19.72/10万,发病率最高年份2007年为33.29/10万,最低年份2013年为9.32/10万。发病年龄构成中,15岁占1.58%,15~44岁占89.91%,≥45岁占8.52%;以20~30岁为发病高峰期;男性多于女性,男女性别比为3.33∶1(14 503/4 354);工人发病数最多,占总病例数42.3%;市郊发病率高于市区。结论深圳市近6年乙肝发病率呈下降趋势;15岁儿童病例显著减少,表明乙肝疫苗接种成效显著。     

2012—2019年上海市某三甲医院境外输入性传染病病例特征分析

本研究分析近年来上海市境外输入性传染病的病例特点,为上海市输入性传染病的防控提供依据。对上海市某三甲医院2012—2019年报告的所有法定及重点监测传染病中确定为境外感染的305例传染病病例进行回顾性分析。采用WPS Office 2019和 SPSS17.0软件对所收集病例的病种、数量、输入时间、病例人口学特征以及输入地区等进行整理分析。结果显示,2012—2019年该院报告境外输入性传染病11种,分别为疟疾、登革热、肺结核、麻疹、甲型肝炎、戊型肝炎、伤寒、人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染、黄热病、白喉、隐性梅毒。确诊的305例病例中,疟疾226例,占74.10%;登革热68例,占22.30%;其他9种疾病共11例,占3.6%。疟疾、登革热全年均有输入,其中6月、9月和11月为疟疾输入高峰,6～8月为登革热输入高峰,肺结核、麻疹、甲型肝炎、戊型肝炎、伤寒、HIV感染、黄热病、白喉、隐性梅毒无明显季节性分布特征。输入性病例中,中国籍多于外籍,男性多于女性,以青壮年为主;主要职业为商业服务和工人;主要输入地为非洲。本研究结果提示境外输入性传染病以疟疾、登革热等虫媒传染病为主,病种呈现多样化的变化趋势,输入高峰主要在夏秋季。应加强非洲、东南亚劳务和旅游人群的健康教育,做好病例监管和防蚊、灭蚊,减少二代病例。     

Survival of Murine Norovirus,Tulane Virus,and Hepatitis A Virus on Alfalfa Seeds and Sprouts during Storage and Germination

Human norovirus (huNoV) and hepatitis A virus (HAV) have been involved in several produce-associated outbreaks and identified as major food-borne viral etiologies. In this study, the survival of huNoV surrogates (murine norovirus [MNV] and Tulane virus [TV]) and HAV was investigated on alfalfa seeds during storage and postgermination. Alfalfa seeds were inoculated with MNV, TV, or HAV with titers of 6.46 ± 0.06 log PFU/g, 3.87 ± 0.38 log PFU/g, or 7.01 ± 0.07 log 50% tissue culture infectious doses (TCID₅₀)/g, respectively. Inoculated seeds were stored for up to 50 days at 22°C and sampled during that storage period on days 0, 2, 5, 10, and 15. Following storage, virus presence was monitored over a 1-week germination period. Viruses remained infectious after 50 days, with titers of 1.61 ± 0.19 log PFU/g, 0.85 ± 0.21 log PFU/g, and 3.43 ± 0.21 log TCID₅₀/g for MNV, TV, and HAV, respectively. HAV demonstrated greater persistence than MNV and TV, without a statistically significant reduction over 20 days (<1 log TCID₅₀/g); however, relatively high levels of genomic copies of all viruses persisted over the testing time period. Low titers of viruses were found on sprouts and were located in all tissues as well as in sprout-spent water sampled on days 1, 3, and 6 following seed planting. Results revealed the persistence of viruses in seeds for a prolonged period of time, and perhaps of greater importance these data suggest the ease of which virus may transfer from seeds to sprouts and spent water during germination. These findings highlight the importance of sanitation and prevention procedures before and during germination.     

INFECTIOUS HEPATITIS—Report of an Outbreak of 24 Cases

In an epidemic of 24 cases of infectious hepatitis in a small lumbering community, the majority of cases occurred in children. Sixteen of them were pupils in one school. The school apparently was the focus for the spread of infection, which is thought to have been through contact between persons. Five multiple case households with eight secondary cases were observed. With one exception, gamma globulin was not used for the prophylaxis of infectious hepatitis in families in which one member had the disease.     

Chemoprevention trial of human hepatitis with selenium supplementation in China

A three-year study has been conducted for prevention of infectious hepatitis with supplementation of table salt fortified with 15 ppm anhydrous sodium selenite to the general population of 20,847 persons in a township M.Z. at Qidong County, Jiangsu Province, China. The results showed that the incidence of virus hepatitis infection in the test township was significantly lower than that of controls provided with normal table salt. The incidence rate of infectious hepatitis in the treated township M.Z. was 1.20 and 4.52 per 1,000, whereas the average incidence in the 6 surrounding control townships was 2.96 and 10.48 per 1,000 in 1986 and 1987, respectively. The incidence of hepatitis B surface antigen (HBsAg+) was 13.2% vs 19.23% for males and 10.42% vs 12.24% for females in the supplemented vs nonsupplemented neighboring township, respectively. Epidemiological studies have demonstrated that a low grain Se content is associated with a high regional incidence of hepatitis B virus infections.     

Infectious hepatitis; report of an outbreak of 24 cases

In an epidemic of 24 cases of infectious hepatitis in a small lumbering community, the majority of cases occurred in children. Sixteen of them were pupils in one school. The school apparently was the focus for the spread of infection, which is thought to have been through contact between persons. Five multiple case households with eight secondary cases were observed. With one exception, gamma globulin was not used for the prophylaxis of infectious hepatitis in families in which one member had the disease.     

Apolipoprotein c1 association with hepatitis C virus

Accumulating evidence suggests that cellular lipoprotein components are involved in hepatitis C virus (HCV) morphogenesis, but the precise contribution of these components remains unclear. We investigated the involvement of apolipoprotein C1 (ApoC1) in HCV infection in the HCV pseudotyped particle system (HCVpp), in the recently developed cell culture infection model (HCVcc), and in authentic HCV isolated from viremic chimpanzees. Viral genomes associated with HCVcc or authentic HCV were efficiently immunoprecipitated by anti-ApoC1, demonstrating that ApoC1 was a normal component of HCV. The infectivities of HCVpp that had been mixed with ApoC1 and, more importantly, untreated HCVcc collected from lysates or media of infected Huh7.5 cells were directly neutralized by anti-ApoC1. Indeed, convalescent anti-HCV immunoglobulin G and anti-ApoC1 each neutralized over 75% of infectious HCVcc particles, indicating that many, if not all, infectious particles were recognized by both antibodies. Moreover, peptides corresponding to the C-terminal region of ApoC1 blocked infectivity of both HCVpp and HCVcc. Altogether, these results suggest that ApoC1 associates intracellularly via its C-terminal region with surface components of virions during viral morphogenesis and may play a major role in the replication cycle of HCV.     

Immunologic effects of interferon-alpha in man: treatment with human recombinant interferon-alpha suppresses in vitro immunoglobulin production in patients with chronic type B hepatitis

The effect of human recombinant interferon-alpha on lymphocyte proliferation and differentiation was studied in 18 patients with chronic type B hepatitis who were participating in a randomized controlled trial of interferon-alpha therapy. Peripheral blood mononuclear cells (PBMC) were obtained by lymphopheresis before and during a 4 mo course of interferon. Pokeweed mitogen-induced immunoglobulin synthesis by PBMC obtained from patients before therapy was similar to that of PBMC from normal individuals. However, after 2 wk treatment with human recombinant interferon-alpha mitogen-induced immunoglobulin production was decreased by an average of 50%. Staining for cytoplasmic immunoglobulin revealed decreases that paralleled secreted immunoglobulin, indicating that interferon-alpha treatment inhibited immunoglobulin synthesis. Mixing autologous T and B cell enriched populations from before and during interferon treatment revealed that the decrease in immunoglobulin synthesis involved a defect in the B cell-enriched population. In contrast to immunoglobulin synthesis, pokeweed mitogen-induced lymphocyte proliferation was not significantly affected by in vivo administration of interferon-alpha. Thus a major effect of in vivo interferon-alpha on immunoregulation in patients with chronic type B hepatitis appears to be an inhibition of the late stages of B cell differentiation into immunoglobulin producing and secreting plasma cells.     

Clinical Problems: Hepatitis in Dialysis Units in the United Kingdom

A prospective study of hepatitis in 20 dialysis units in the United Kingdom showed that the number of units with outbreaks increased from one in 1968 to three in 1969 and the overall attack rate rose from 1·7 to 5·3% in patients and from 0·5 to 1·3% in staff.In July 1969 a pilot study of patients'' sera showed that all of the outbreaks were associated with Australia (Au) antigen. Au antigen was not detected in the unaffected units or in one unit in which there were several patients with abnormal liver function.In January 1970 systematic prospective testing for Au antigen was begun. Au antigen was detected in single patients in five more of the 20 units. The transfer of the affected patients to isolation for dialysis seemed to prevent the spread of infection in the units. The incidence of hepatitis in 1970 was 5·6% in patients and 0·4% in staff.     

Modulation of hepatitis B infection by intravenous application of an immunoglobulin preparation that contains antibodies to hepatitis B e and core antigens but not to hepatitis B surface antigen.

Repeated administration of an intravenous immunoglobulin containing antibody to hepatitis B e antigen (anti-HBe) and antibody to hepatitis B core antigen (anti-HBc) but free of antibody to hepatitis B surface antigen (anti-HBs) before and after the inoculation of 10(4.9) 50% chimpanzee infective doses of hepatitis B virus (HBV) markedly prolonged the incubation period of HBV in experimentally infected chimpanzees. Similar administration of an immunoglobulin preparation containing anti-HBc but free of anti-HBe and anti-HBs or intramuscular administration of a single dose of immunoglobulin containing anti-HBe and anti-HBc 3 days before or after inoculation with HBV did not appear to modulate HBV infection. These observations suggested that anti-HBe, or an unidentified antibody associated with it, may have biological activity in the modulation of HBV replication.     

Prevalence of Hepatitis B Antigen and Antibody in Prostitutes

We investigated the prevalence of hepatitis B antigen (HBAg) and antibody (HBAb) in 293 prostitutes and in 379 pregnant women of similar age and of low socioeconomic level, who served as controls. HBAg was found in 4·4% of prostitutes and 3·4% of controls. The prevalence of HBAb was significantly higher (P <0·001) in prostitutes (56·7%) than in controls (24·5%). The prevalence of HBAb was clearly age-dependent in both groups. Evidence of hepatitis B virus infection significantly increased with the number of years in prostitution. The evidence of increased infection rates among prostitutes and their distribution support the hypothesis that hepatitis B infection is sexually transmitted.     

剑阁县2001-2010年法定传染病流行特征及防治对策分析

目的：通过分析10年法定传染病疫情的流行趋势和三间分布特征,为制定传染病预防控制策略和措施提供依据。方法：采用描述性流行病学方法分析疫情趋势和三间分布情况,数据资料用SPSS10．0和Excel2003进行统计分析。结果：2001～2010年共报告乙、丙类传染病25种26129例,年均发病率386．89／10万,年均死亡率0．15／10万,10年间报告法定传染病以血源及性传播传染病和呼吸道传染病为主,居第1位的是血源及性传播传染病,共报告5种12453例,占53．03％;其次是呼吸道传染病,共报告5种9828例,占41．85％,近3年发病居于各类传染病首位;第三位的是肠道传染病,共报5种1149例,占4．89％。发病居前5位的传染为乙肝、肺结核、流行性腮腺炎、痢疾、麻疹,主要传染病以乙肝、肺结核为主,近年性传播疾病呈快速增长趋势。结论：血源及性传播传染病和呼吸道传染病是今后重点防控传染病。