Serological studies of influenza viruses in pigs in Great Britain 1991-2.

Samples from a sow serum bank representative of the pig population of Great Britain collected during 1991-2, were examined for antibodies to influenza A, B and C viruses, using viruses which had been isolated from a variety of hosts. For influenza A viruses there was evidence of the continued circulation of classical swine H1N1 virus (26%) seroprevalence), and human H3N2 viruses (39%) which are antigenically most closely-related to A/Port Chalmers/1/73 virus. In addition antibodies were detected to A/swine/England/201635/92 (8%), a strain of H3N2 virus which appears to have arisen by antigenic drift from conventional H3N2 swine strains. Specific antibodies (2%) were detected to an H1N1 virus (A/swine/England/195852/92) related most closely to avian H1N1 strains. In tests with human H1N1 and H3N2 viruses, excluding isolates from pigs, the highest seroprevalence was detected to the prevailing strains from the human population. Serological tests with avian H4 and H10, human H2, equine 1 and 2 influenza A viruses were all negative. Seven pigs seropositive by haemagglutination-inhibition, virus neutralization and immunoblotting assays for antibody to influenza B virus, were randomly distributed geographically suggesting that influenza B viruses may be transmitted to pigs but fail to spread. The seroprevalence to influenza C viruses was 9.9% indicating that these viruses are widespread in pigs. These results provide further evidence that the pig can be infected by a number of influenza viruses, some of which may have significance in the epidemiology of human influenza.     

Major core proteins, p24s, of human, simian, and feline immunodeficiency viruses are partly expressed on the surface of the virus-infected cells.

We have previously shown the expression of human immunodeficiency virus type 1 (HIV-1) major gag protein, p24, on the surface of persistently HIV-1-infected cells by using murine monoclonal antibodies (mAb). We now report that the cell surface gag p24 antigen expression is a universal phenomenon among HIV-1, simian immunodeficiency virus (SIV), and feline immunodeficiency virus (FIV). The mAbs prepared by immunization with purified HIV-1 particles were used as antibodies cross-reactive to HIV-1 and SIVagmp24 antigens. The mAbs to FIV p24 were raised against the gag precursor 50 kDa protein of FIV, which was expressed by Baculovirus vector. The p24 antigen expression on the cell surface was detectable in certain combinations of virus-host cell systems in all of these viruses. Since these p24 regions of the animal viruses seem to play as important a role in cell-mediated immunity as that of HIV-1, the p24 applicability as a candidate epitope for vaccine development could be evaluated in those animals.     

Species-specificity of a murine immunocontraceptive utilising murine cytomegalovirus as a gene delivery vector

Cytomegaloviruses are species-specific DNA viruses. Recombinant murine cytomegaloviruse (MCMV) expressing the mouse egg-coat protein zona pellucida 3 (mZP3) has been shown to sterilise female mice by breaking self-tolerance and inducing an immune response against the host ZP3. This virus has the potential to be used for mouse population control, however the effect of this recombinant immunocontraceptive virus in non-host species must be determined. Recombinant MCMV-mZP3, based on both laboratory and wild strains of virus, induced long-lived antibody responses against structural viral proteins and mZP3 when inoculated into laboratory rats, although no viral DNA or replicating virus was identified. The anti-mZP3 antibodies were specific for mouse ZP3, did not cross-react with rat ZP3, and had no effect on the fertility of the rats.     

Use of GFP-expressing influenza viruses for the detection of influenza virus A/H5N1 neutralizing antibodies

The hemagglutination inhibition (HI) assay is used most commonly for the detection of antibodies to influenza viruses. However, for the detection of antibodies to avian influenza viruses of the H5N1 subtype either induced by infection or by vaccination, the HI assay is insensitive. Therefore, the virus neutralization (VN) assay has become the method of choice to detect human serum antibodies directed to these viruses. However, this assay requires a second assay for the detection of residual virus replication, which makes it laborious to perform and less suitable for high throughput testing of large numbers of samples. Here we describe an alternative method for the detection of these antibodies, which is based on the use of reporter viruses that express the green fluorescent protein (GFP) upon infection of target cells. GFP-expressing viruses were generated carrying the HA of a variety of antigenically distinct H5N1 influenza viruses. The method proved easy to perform and could be carried out rapidly. Using a panel of antisera raised against H5N1 influenza viruses, the assay based on GFP expressing viruses was compared with the classical virus neutralization assay and the hemagglutination inhibition assay. In general, the results obtained in these assays correlated well. It was concluded that the assay based on the reporter viruses is an attractive alternative for the classical virus neutralization assay and suitable for large sero-epidemiological studies or for the assessment of vaccine efficacy in clinical trials.     

Seroepidemiology of hepatitis A and E virus infections in Tehran, Iran: a population based study

Hepatitis A virus (HAV) and hepatitis E virus (HEV) are enteric hepatotropic viruses and their prevalence is related to the sanitary conditions of the region under investigation. There are only a few studies on the seroepidemiology of these two viruses in the general Iranian population. The purpose of this investigation was to measure the prevalence of hepatitis A and E infections in the general population. Between 2006 and 2007, a cross sectional study was performed in Tehran, Iran. Blood specimens were collected and questionnaires were filled in for 551 persons. Patient sera were tested by ELISA for anti-HEV and anti-HAV IgGs. The χ(2) test and independent t-test were used for statistical analysis and p<0.05 was considered significant. The overall seroprevalence rates of anti-HEV IgG and anti-HAV IgG were 9.3% and 90%, respectively. The prevalence of antibodies to HAV and HEV was greater among men than women and increased with age. However, there was no significant relationship between age and gender with the existence of anti- HAV and HEV IgG antibodies. Our results show the seroprevalence of HAV and HEV antibodies are high and both viruses are endemic in this region. These findings are in accordance with results obtained from previous studies. We recommend that foreign travelers to Iran are vaccinated against HAV.     

A serological survey of antibodies to selected enteroviruses

Sera from various population groups in Liberia, Colombia, Peru and Southern Louisiana, USA, have been studied for the presence of neutralizing antibodies to the following enteroviruses: poliovirus type 1, Coxsackie viruses B5 and A9, and ECHO viruses E6 and E9. The results obtained indicate that these viruses are world-wide in distribution and that infection (though not necessarily disease) occurs at an early age. Variations in antibody patterns occur, most notably with Coxsackie B5 virus. Environmental conditions apparently influence the spread of virus, but other factors, as yet unknown, may also play an important role in the dissemination of an organism. It is suggested that surveys such as these might be useful to indicate populations in need of particular vaccines.     

Infections due to the human herpesviruses in southern India: a seroepidemiological survey

We studied the prevalence of IgG and IgM antibodies to the human herpesviruses in a hospital-based population of 181 individuals aged 0 to 25 years, who were resident in Vellore, south India or surrounding rural areas. Antibodies to the Epstein-Barr virus (EBV) viral capsid antigen were determined by indirect immunofluorescence, while antibodies to the remaining herpesviruses were determined by enzyme-linked immunosorbent assay. The age-specific prevalence rates of IgG antibodies to EBV and cytomegalovirus (CMV) rose rapidly after birth to reach a value of over 90% by the fourth year of life. High age-specific IgM prevalence rates and geometric mean titres (GMT) of IgG antibody in children 6 months to 2 years of age, and the early median age of virus infection (1.4 years for EBV and less than 1 year for CMV) indicate that primary infection with these viruses occurs early in life. In contrast, age-specific prevalence rates of IgG antibodies to varicella-zoster virus (VZV) and herpes simplex virus (HSV) rose gradually after birth to attain maximal values of only 72% (VZV) and 83% (HSV) in the 15-25 year age group, and the median ages of infection were delayed (12.25 years for VZV and 8.2 years for HSV). The age-specific IgG prevalence rates of VZV and HSV, and of EBV and HSV showed statistically significant positive correlations, suggesting that common epidemiological factors may underlie the pattern of infections due to these groups of viruses.(ABSTRACT TRUNCATED AT 250 WORDS)     

An investigation into natural resistance to African swine fever in domestic pigs from an endemic area in southern Africa

A population of domestic pigs in northern Mozambique with increased resistance to the pathogenic effects of African swine fever (ASF) virus was identified by the high prevalence of circulating antibodies to ASF virus. An attempt was made to establish whether the resistance in this population was heritable. Some of these pigs were acquired and transported to a quarantine facility and allowed to breed naturally. Offspring of the resistant pigs were transferred to a high security facility where they were challenged with two ASF viruses, one of which was isolated from one of the Mozambican pigs and the other a genetically closely-related virus from Madagascar. All but one of the 105 offspring challenged developed acute ASF and died. It therefore appears that the resistance demonstrated by these pigs is not inherited by their offspring, or could not be expressed under the conditions of the experiment. The question remains therefore as to the mechanism whereby pigs in the population from which the experimental pigs were derived co-existed with virulent ASF viruses.     

Respiratory virus antibodies in sera of persons living in isolated communities

It is known that young adults living in urban areas of many different parts of the world have serum antibodies against a number of viruses commonly associated with respiratory disease. It seemed possible that people living in isolated regions of the world, having infrequent contact with others, might have fewer virus infections, and, if so, that this would be reflected in an infrequent occurrence or low level of antibodies in their sera. Therefore sera were obtained from children and adults living in remote village-type communities in the Pacific (Micronesian islanders), North America (Eskimos) and South Africa (Hottentots). Antibodies against influenza viruses A2 and B, parainfluenza virus types 1, 2 and 3, reovirus types 1, 2 and 3, and two M rhinoviruses were present usually in a high proportion of sera in the three population groups; the results differed little from those for non-isolated communities. It seems that an extreme degree of isolation is required to reduce contact with viruses so that a population has little or no antibody.     

Seroepidemiological surveys of tick-borne encephalitis virus and novel tick-borne viruses in wild boar in Nagasaki,Japan

In Japan, tick-borne viruses such as tick-borne encephalitis virus (TBEV) and severe fever with thrombocytopenia syndrome virus have been identified in humans, animals, and ticks. In addition, novel tick-borne viruses have been isolated from ticks in Japan. This study aimed to determine the seroprevalence of TBEV and novel viruses, particularly Tofla virus (TFLV), Kabuto Mountain virus (KAMV), and Muko virus (MUV) in wild boar in Nagasaki, Japan. Enzyme-linked immunosorbent assays and neutralization tests were performed to detect antibodies against each virus. Wild boar serum tested positive for antibodies against KAMV, TFLV, and TBEV, but not MUV. This study revealed the seroprevalence of newly identified tick-borne viruses and TBEV in animals residing in the Nagasaki area. The seroprevalence of these viruses in sentinel animals may inform policies aimed at preventing tick-borne virus disease outbreaks.     

Serological survey on arbovirus infection in residents of an ecological reserve

OBJECTIVE: Serological inquires conducted in the Ribeira Valley, S. Paulo State, Brazil, showed an intense circulation of pathogenic arboviruses in the region. The goal was to verify the prevalence of arboviral infections in people living at the local ecological, and its potential association with these population' individual and familiar characteristics. METHODS: The study was carried out among 182 persons of 58 families to identify the presence of antibodies to the following viruses: Rocio (ROC), Ilheus (ILH), Eastern equine encephalitis virus (EEE), Western equine encephalitis virus (WEE), Venezuelan equine encephalitis virus (VEE) and St. Louis encephalitis virus (SLE). Inhibition hemagglutination test and plaque reduction neutralization test were the laboratory assays of choice. MAC-ELISA was used to identify IgM antibodies to ROC, ILH and EEE viruses. RESULTS: The prevalence of antibodies was 26.9% (21. 4% to alphavirus and 12.6% to flavivirus). There were no antibodies to WEE virus. IgM antibodies were not observed suggesting no recent infection in study population. Among the characteristics investigated, age, occupation, place of birth and the habit of going into the forest were shown to be statistically associated with arboviral infection (p<0.05). CONCLUSIONS: It was observed an intense circulation of pathogenic arboviruses, especially VEE. It seems the habit of going into the forest is the most important factor to this population exposure to the mosquito vectors of arboviruses. The results suggest the need of further investigation to clarify the role of birds as arbovirus infection amplificators indoors.     

High prevalence rates of antibody to three sandfly fever viruses (Sicilian, Naples, and Toscana) among Cypriots.

Neutralizing antibodies to sandfly fever Naples, sandfly fever Sicilian and Toscana viruses were investigated among 479 sera collected from a normal human population in Cyprus. Antibody prevalence rates of 57%, 32% and 20% were found to Naples, Sicilian and Toscana viruses, respectively. The observed frequency of dual and triple infections was higher than would be expected with a random chance of infection. Antibody prevalence rates were similar for men and women for all three viruses tested, but one of two study sites had significantly higher antibody prevalence to Naples and Sicilian viruses than the other. Individuals with antibodies to both Naples and Toscana viruses had higher antibody levels to Naples virus than those with antibodies to Naples virus only. If the antibody prevalence rates found in this study reflect a history of clinical disease as described in the literature, sandfly fever poses a significant public health problem in Cyprus.     

某部新兵常见呼吸道病毒血清IgM抗体的检测

目的了解某部新兵人群中常见呼吸道病毒的感染状况,为新兵人群呼吸道感染性疾病的预防和控制提供依据。方法对目标人群采取整群抽样,采用ELISA诊断试剂盒检测1449名新兵血清中流感病毒A（Flu A）、流感病毒B（Flu B）、副流感病毒1、2、3型（PIV1、2、3）、腺病毒（ADV）和呼吸道合胞病毒（RSV）共5种病毒IgM抗体。结果检测的5种呼吸道病毒感染在某部新兵人群中均存在,按照病毒感染率高低依次为Flu A（35.6%）、Flu B（28.2%）、PIV（24.8%）、ADV（13.5%）和RSV（6.7%）。不同病毒感染率在不同地区之间存在差异。结论新兵人群对5种呼吸道病毒均易感,以流感病毒感染率最高。     

Antibodies to La Crosse virus in eastern chipmunks in Indiana near an Aedes albopictus population.

Blood samples of 34 Eastern chipmunks trapped in the vicinity of an Aedes albopictus population near New Alsace, IN, were tested for neutralizing antibodies to La Crosse (LAC) virus and other California group viruses. Two samples were positive for LAC antibodies. Analysis of mosquito bloodmeals demonstrated that both Ae. albopictus and Ae. triseriatus from the site fed on chipmunks. This note documents the first record of LAC antibodies in sylvan rodents from Indiana, the presence of LAC virus in the vicinity of Ae. albopictus and that wild Ae. albopictus feed on Eastern chipmunks.     

Role of hepatitis E and other hepatotropic virus in aetiology of sporadic acute viral hepatitis: A hospital based study from urban Delhi

Major hepatotropic virus continues to be an important cause of acute viral hepatitis (AVH) in developing countries like India. While epidemics of AVH have been well studied few serious sporadic cases from developing countries have been reviewed. We studied prospectively 75 cases of sporadic AVH who reported to our hospital and were evaluated for the presence of various hepatotropic viruses. The seroprevalence of IgG anti-HEV antibodies was studied in the general population as a control. We found 53.3% (40/75) of sporadic AVH cases were due to hepatitis E virus while 11% (8/75) were due to hepatitis B virus. Hepatitis C virus was responsible for 8% (6/75) of the sporadic AVH cases and hepatitis A was found in 5% (4/75) of the cases. No causative agent was found in 23% (17/75) of the sporadic AVH cases. The sporadic AVH cases due to HEV were not clinically or biochemically not different from AVH due to other viruses. We found a high prevalence of IgG anti-HEV in 35.6% (178/500) among the general population of urban Delhi. The study suggested that hepatitis E was the most common cause of sporadic AVH in urban Delhi. High seroprevalence of IgG anti-HEV antibodies in the general population and amongst the sporadic AVH cases suggests that it is unlikely to be protective antibody. IgM anti-HEV positive serology is considered diagnostic of acute hepatitis E infection in India, where hepatitis E is endemic.     

Haemorrhagic fever in Gabon. I. Incidence of Lassa,Ebola and Marburg viruses in Haut-Ogooué

A serological enquiry aimed at determining the incidence of infection with Lassa, Ebola and Marburg viruses was conducted on the human population of the region of Haut-Ogooué (Gabon) and on primates.The results, obtained by the indirect immunofluorescence technique, showed that more than 6% of the human population had had contact with Ebola virus but no antibodies against Marburg or Lassa viruses were found.Most sera reacted to an Ebola antigen from a Zairian strain, but showed little or no reaction to an antigen from a Sudanese strain.     

Sero-surveillance of wild boar in The Netherlands, 1996-1999

From 1996 to 1999, blood samples were collected from wild boar shot during the hunting season in Crown properties, national parks and the free wildlife belt in the Netherlands. Sera were screened for the presence of antibodies against classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), Aujeszky's disease virus (ADV) and Trichinella spiralis. The results of the sero-surveillance system indicate that CSFV, SVDV and ADV are uncommon within the wild boar population. Hence, the wild boar population is not thought to be an important reservoir of these viruses in the Netherlands. Infection with ADV and CSFV is endemic in the wild boar population in Germany. Since contact between the wild boar populations of Germany and the Netherlands cannot be excluded in the southern part of the Netherlands, continuation of the sero-surveillance system seems appropriate. In the decade before 1998, no antibodies to Trichinella spp. were found in the wild boar population of the Netherlands. The detection of some seropositive animals during the hunting season of 1998-1999 corresponds to the previous findings in wild boar before 1988. However, the recent data do not have consequences for the pig industry of the Netherlands, since the country has been considered Trichinella-free for many decades.     

Evaluation of seasonal influenza vaccines for H1N1pdm09 and type B viruses based on a replication-incompetent PB2-KO virus

Vaccination is the first line of protection against influenza virus infection in humans. Although inactivated and live-attenuated vaccines are available, each vaccine has drawbacks in terms of immunogenicity and safety. To overcome these issues, our group has developed a replication-incompetent PB2-knockout (PB2-KO) influenza virus that replicates only in PB2-expressing cells. Here we generated PB2-KO viruses possessing the hemagglutinin (HA) and neuraminidase (NA) segments from H1N1pdm09 or type B viruses and tested their vaccine potential. The two PB2-KO viruses propagated efficiently in PB2-expressing cells, and expressed chimeric HA as expected. Virus-specific IgG and IgA antibodies were detected in mice immunized with the viruses, and the immunized mice showed milder clinical signs and/or lower virus replication levels in the respiratory tract upon virus challenge. Our results indicate that these PB2-KO viruses have potential as vaccine candidates.     

Prevalence of viral antibodies and helminths in field populations of house mice (Mus domesticus) in southeastern Australia.

A 13-month study of wild mice (Mus domesticus) in wheatlands in southeastern Australia contrasted changes in the seroprevalence of antibody to 13 viruses and the occurrence of helminths with changes in their population dynamics. Mice were seropositive for mouse hepatitis virus (MHV), rotavirus, minute virus of mice (MVM), mouse adenovirus (MAdV), reovirus (reo 3), and murine cytomegalovirus (MCMV). The seroprevalences of all but rotavirus varied significantly with time and increased with host density. Near the end of the study, host density declined rapidly and the seroprevalence of MVM and reo 3 increased significantly. These two viruses had low seroprevalence when host survival was high and high seroprevalence when host survival was low, indicating they may play a role in regulating mouse populations. In the case of MVM, there was evidence of a viral epizootic during the decline in mouse abundance. The prevalence of four helminths (Taenia taeniaeformis, Syphacia obvelata, and Vampirolepis spp.) differed significantly with time but showed no apparent association with host density. These findings highlight the need for further study on the effect of viruses on the population dynamics of mice.