Serological evidence of human infection with Pteropine orthoreovirus in Central Vietnam

Pteropine orthoreovirus, potentially of bat origin, has been reported to cause respiratory tract infections among human beings in Southeast Asia. Twelve IgG ELISA‐positive cases with antibodies against Pteropine orthoreovirus were detected among 272 human serum samples collected between March and June 2014 from in and around Hue City, Central Vietnam. These 12 cases were IgM ELISA negative. Neutralizing antibodies were also detected among six of these cases with the highest titer of 1:1,280 in 2 cases (both female, 32 and 68 years old, respectively). This is the first report of human infection with Pteropine orthoreovirus in Central Vietnam. These findings indicate the need for surveillance on Pteropine orthoreovirus infections in Southeast Asia to enable prevention and control strategies to be developed should a change in virulence occur. J. Med. Virol. 87:2145–2148, 2015. © 2015 The Authors. Journal of Medical Virology Wiley Periodicals, Inc.     

Expression of human papillomavirus type 16 E7 protein by recombinant baculovirus and use for the detection of E7 antibodies in sera from cervical carcinoma patients

Although the presence of serum antibodies against the human papillomavirus type 16 (HPV-16) E7 protein has been linked with cervical cancer, currently available assays detect antibodies in only ca. 40% of carcinoma patients. The dependence of these serological assays on synthetic target antigens which present only linear epitopes may be a limiting factor. In order to produce a more realistic target antigen for use in serological assays, we have expressed the HPV-16 E7 protein in insect cells using a recombinant baculovirus vector. Two major E7 forms of ca. 18kDa and 16kDa were produced and characterised. The 16kDa component was shown to be truncated at the N-terminus. A radioimmunoprecipitation assay was developed for the detection of anti-E7 antibodies in human sera. This assay showed a marked increase in detection rate compared with a western blotting method based on bacterially derived E7 fusion proteins. © 1993 Wiley-Liss, Inc.     

Direct correlation between human herpesvirus-8 seroprevalence and classic Kaposi's sarcoma incidence in Northern Sardinia

The human herpesvirus-8 (HHV-8) has been associated with the development of Kaposi's sarcoma. A high incidence of classic Kaposi's sarcoma has been described in Sardinia, an island West of Italy's mainland. Different seroepidemiological analyses have reported that prevalence of HHV-8 infection varies worldwide: a high HHV-8 seroprevalence has been shown in Italy. The present survey was carried out to evaluate the correlation between HHV-8 infection and classic Kaposi's sarcoma incidence in northern Sardinia. Blood samples were collected from 226 healthy donors born and resident in five different areas of North Sardinia. Seroprevalence to HHV-8 was determined searching antibodies to viral lytic proteins by immunofluorescence in sera diluted at 1:10. Classic Kaposi's sarcoma incidence data spanning a period of 23 years were examined in the areas studied. The present screening revealed that seroprevalence was 35%, within a range of 15.3-46.3% in the five areas, although it should be considered that the seroprevalence to HHV-8 can be established more accurately by the combined use of different assays. Age emerged as an important risk factor. Indeed, subjects aged > 50 years showed a higher seroprevalence to HHV-8 as compared with younger individuals. A strong direct correlation between HHV-8 prevalence and classic Kaposi's sarcoma incidence has been also observed. The wide diffusion of HHV-8 in Sardinia appears to represent an important factor in the high incidence of classic Kaposi's sarcoma reported in the island. However, additional co-factors, such as age, sex, genetic traits, or viral strain pathogenicity, are likely to play a role in the development of the disease.     

Enzyme immunoassay using baculovirus-expressed human calicivirus (Mexico) for the measurement of IgG responses and determining its seroprevalence in London,UK

The use of an enzyme immunoassay (EIA) employing a baculovirus-expressed recombinant human calicivirus (Mexico virus, MxV) for the detection of IgG-specific antibodies is described. MxV appeared to be related antigenically to a strain of small round structured virus, SRSV/UK4/Leeds/91, which had previously been shown by solid phase immune electron microscopy (SPIEM) to be related to Snow Mountain agent (SMA). One other outbreak which occurred in San Anita, USA in 1980 and was due to consumption of contaminated water was caused by a virus antigenically related to MxV. Volunteers and patients who developed significant IgG responses to rMxV showed anamnestic IgG responses (2 to 4-fold) in the recombinant Norwalk virus (rNV) IgG assay. Patients and volunteers who were known to have been infected with several other strains of calicivirus/small round spherical viruses (SRSV) including NV and SRSV UK3 showed no significant antibody response to rMxV in the EIA. A seroepidemiological survey of sera from 338 children in London showed that infection with MxV occurred earlier in life than NV. Primary infections with MxV were common after the age of 6 months. Over 70% of children had evidence of infection by the age of 2 years, whereas only 12% of these children had been infected with NV. High concentrations of maternal antibody were present during the first month of life which was detected in 96% of the neonates. The results suggest that the high sensitivity of the EIA may be detecting maternal antibody throughout the first 8 months of life. © 1995 Wiley-Liss, Inc.     

Changing seroepidemiological patterns of cytomegalovirus infection in children in Taiwan from 1984 to 1989.

The prevalence of cytomegalovirus (CMV) antibody was studied in 966 children in 1984 and 927 children in 1989. The overall prevalence rate of CMV antibody was 59% for children in 1984 and 46% for children in 1989 (P less than 0.05). In both study years, the prevalence rate of CMV antibody was about 70% in infants under 6 months of age, declined to a trough between the ages of 6 and 12 months, and then increased to 40-50% between 1 and 4 years of age. The rate of CMV antibody for children above 4 years in 1984 increased steadily with age and reached 82% by 12 years. In contrast, the prevalence rate in 1989 remained at the level of 40-50% from age 4 to 10 years. It was followed by a sharp increase after 10 years of age and reached 84% at 12 years old. The seropositive rate in each of the 5-, 6-, 8-, 9-, and 10-year-old groups was higher in 1984 than that in 1989. These observations indicated that the prevalence rate of CMV antibody is decreasing in children. This change may be related to various socioeconomic factors, especially the less crowded family conditions in recent years.     

HTLV-I/II infection in a high viral endemic area of Zaire,Central Africa: Comparative evaluation of serology,PCR, and significance of indeterminate Western blot pattern

The frequency of indeterminate Western blot (WB) seroreactivities against HTLV-I “gag encoded proteins” only, and the use of low specific diagnostic WB criteria led to the overestimation of HTLV-I seroprevalence in initial studies in intertropical Africa and Papua New Guinea. In order to clarify the meaning of such seroreactivity, 98 blood samples of individuals from a high HTLV-I endemic area in Zaire, Central Africa were studied by a WB assay containing HTLV-I disrupted virions enriched with a gp 21 recombinant protein and a synthetic peptide from the gp 46 region (MTA-1), and by the polymerase chain reaction (PCR) with 3 primers pairs and 4 different HTLV-I and or HTLV-II-specific probes. These 98 samples were taken mainly from patients with neurological diseases and from their relatives. Using stringent WB criteria, 28 sera (29%) were considered as HTLV-I-positive, 3 as negative and 67 (68%) as indeterminate. A large proportion of these indeterminate sera would have been considered as HTLV-I-positive samples according to previous low specific WB diagnostic criteria. After PCR, 35 samples (36%) were considered as positive for the presence of HTLV-I proviral DNA. Out of the 67 WB seroindeterminate, 10 (15%) were found HTLV-I-positive by PCR. These 10 individuals exhibited in WB multiple band reactivity with p19 and/or p24 (7 cases of both) associated in 6 cases with rgp 21, but never with MTA-1. No samples were found PCR-positive for HTLV-II despite the findings of 11 sera suggestive of HTLV-II by WB. These findings demonstrate that even in a high HTLV-I endemic area, only a minority (about 15%) of the WB-seroinde-terminate individuals could be considered as infected by HTLV-I, and that very stringent WB criteria could lead to overlooking some infected individuals. © 1994 Wiley-Liss, Inc.     

Epidemiology of intracellular pathogens

Epidemiologic studies of Chlamydia pneumoniae have been conducted throughout the world. A rate of antibody prevalence of approximately 50% has been found in adults, with small regional differences. We studied the antibody prevalence of C. pneumoniae in healthy persons and patients with acute respiratory infections in Japan. The microplate immunofluorescence antibody (MFA) technique was used for measuring antibodies, and the cases with IgG titers of ≥ 1:64 were considered to have had past chlamydial exposure. Using this criterion, positive serum antibodies against C. pneumoniae were found in 67.4% of healthy subjects and 74.2% of adult patients with respiratory infections. Some seroepidemiologic studies in Western countries have shown that epidemics of C. pneumoniae respiratory infections occur in a 4–6-year cycle, like a Mycoplasma pneumoniae infection. However, during our 7-year survey from 1988 to 1994, we were not able to observe any epidemic episodes. The prevalence of the antibody was lower than 10% in children 5 years old or younger. It increased rapidly between ages 6 and 15, reaching a plateau of 60%.
Results suggest that in Japan a high infection rate might occur in children at nursery schools, kindergartens and elementary schools. We encountered an outbreak of C. pneumoniae infection and we were able to trace the source of the infection to a family and the spread of the infection to the schools which the children attended. Transmission is of the non-vector type. The incubation period is 3 to 4 weeks. Transmission occurs only after repeated and close contacts. Small outbreaks may occur in households and schools where persons have prolonged close contacts. Unlike acute viral infections, it may spread slowly.     

2001～2005年江苏省盐都区病毒性肝炎血清流行病学监测

目的研究一般人群血清病毒性肝炎免疫水平。方法在省级病毒性肝炎血清流行病学监测点内分别于2001、2003、2005年对一般人群免疫水平进行血清流行病学监测,用酶联免疫吸附法(ELISA)检测抗-HAV-IgG、HBsAg、抗-HBs、抗-HBc、抗-HCV等。结果抗-HAV-IgG总阳性检出率为82.38%,HBsAg总阳性检出率2.79%,抗-HBs总阳性检出率57.04%,抗-HBc总阳性检出率46.94%,抗-HCV总阳性检出率0.08%。结论一般人群甲型肝炎抗体较高,表明有关控制甲型肝炎的干预措施切实有效。乙型肝炎防治措施的重点应为,加强对10￣20岁年龄组的疫苗接种。     

我国部分地区鹿、牛群中戊型肝炎病毒血清流行病学调查

目的调查我国部分地区鹿和牛群戊型肝炎病毒（HEV）感染情况。方法采集我国某地区13个鹿场780份鹿血，2个散养鹿群18份血和长春地区牛血80份，分离血清。应用抗HEV抗体酶联免疫试剂盒（双抗原夹心法）对血清样品进行抗HEV抗体检测。用χ^2检验分析不同养殖场鹿血清HEV抗体水平。结果798份鹿血清抗HEV抗体阳性率为43．61％。13个集约化养殖鹿场中有5个鹿场的血清样品抗体呈阳性，阳性率分别为48．02％、47．25％、60．69％、41．94％、40．91％；其余8个鹿场的血清样品均为阴性。两个散养鹿群的抗体阳性率分别为40．00％和46.15％。80份牛血清样品的抗体阳性率为20％。结论我国鹿群尤其是散养鹿群普遍存在HEV感染。牛群也存在较高的HEV感染率。