Infection of owl monkeys (Aotus trivirgatus) and cynomolgus monkeys (Macaca fascicularis) with hepatitis E virus from Mexico.

Owl and cynomolgus monkeys were inoculated with hepatitis E virus (HEV) to compare disease models and produce antibody and virus. By immune electron microscopy (IEM), all six owl monkeys were shown to have serologic responses manifested by unusually high levels of anti-HEV at 6 months, but only three developed hepatitis. Virus-related antigen in liver (HEV Ag) was detected by immunofluorescence microscopy of biopsies from two of four owl monkeys; one with HEV Ag also had HEV in acute-phase bile (detected by IEM) and feces (detected by infecting another owl monkey). In contrast, cynomolgus monkeys propagated HEV to higher levels and all five had hepatitis. Moderate-to-high levels of HEV Ag correlated with detectable HEV in bile for both species. Thus, the value of using HEV-infected cynomolgus was confirmed. Owl monkeys were shown to be HEV-susceptible and sources of high-level anti-HEV; Sustained anti-HEV in these monkeys may also be useful for understanding immune responses.     

Swine hepatitis E virus in rural southern China: genetic characterization and experimental infection in rhesus monkeys (Macaca mulatta)

BACKGROUND: In rural areas of southern China, where hepatitis E is endemic, residents generally rear pigs in pigsties near their houses. The study was conducted to assess the possibility that hepatitis E virus (HEV) infections in this region are acquired primarily through contact with swine. METHODS: One hundred twenty swine fecal samples collected from pigsties located in eight rural communities of southern China were tested for HEV RNA. The swine HEV isolates were analyzed genetically and were experimentally inoculated into rhesus monkeys to determine the potential risk of cross-species infection. RESULTS: Twenty-nine of the 120 swine fecal samples were positive for HEV RNA. The nucleotide sequences of these swine HEV strains shared 85%-99% identities with the local human genotype 4 isolates and belonged to two subgroups of genotype 4. Importantly, swine HEV strains representing both subgroups induced hepatitis in rhesus monkeys by inoculation with the virus, evidenced by elevated serum alanine transaminase (ALT), viremia, fecal viral shedding, anti-HEV seroconversion, and liver histopathological changes. CONCLUSIONS: Swine may be the principal reservoir for human HEV infection in rural southern China.     

Type-IV Indian swine HEV infects rhesus monkeys

In contrast to countries reporting zoonotic spread of hepatitis E virus (HEV), distinct genotypes circulate in humans (genotype 1) and pigs (genotype 4) from India indicating rarity of such spread. Pigs were refractory to human HEV. As rhesus is an excellent animal model for human HEV, an attempt was made to infect rhesus monkeys with swine HEV. Experimental infection of both the rhesus monkeys with swine-HEV as evidenced by seroconversion to anti-HEV antibodies and presence of viraemia suggests possibility of human infections or differential susceptibility. Comparison of Open Reading Frame-2 and hypervariable regions of HEV genomes showed identity of swine and monkey-derived HEV.     

Prevalence of anti-hepatitis E virus antibodies in different Indian animal species

Prevalence of IgG antibodies to hepatitis E virus (IgG-anti-HEV) was determined among different animal species from India. Seropositivity varied from 4.4% to 6.9% in cattle, 54.6–74.4% in pigs and 2.1–21.5% in rodents. Of the 44 dogs screened, 10 were positive (22.7%). None of the 250 goat sera tested were found to be anti-HEV positive. Among rodents, over 50% serum samples collected in 1985 from Bandicota bengalensis were positive for anti-HEV antibodies. No evidence of HEV infection was obtained following experimental inoculation of an Indian strain (AKL-90) of HEV into anti-HEV negative pigs and goats. The results document varied prevalence of anti-HEV antibodies in different animal species from India and of inability of Indian pigs and goats to support replication of at least one human strain of HEV.     

戊型肝炎病毒核酸阳性血浆经输血传播感染恒河猴的研究

目的了解戊型肝炎病毒(HEV)核酸阳性血浆对灵长类动物的感染性和致病性。方法对抗-HEV IgM阳性而IgG阴性志愿献血员血浆进行HEV RNA检测，并将存在病毒血症献血员的10ml血浆静脉输入健康恒河猴，观察其对恒河猴的感染性和致病性。结果从1份抗-HEV IgM阳性而IgG阴性志愿献血员血浆中分离出HEV基因IV型RNA片段。该份血浆输入恒河猴后，恒河猴出现典型急性肝炎生物化学和病理表现，病毒血症，血清抗-HEV IgM和IgG抗体阳转。结论HEV病毒血癌献血员血浆输入可以引起灵长类动物的HEV感染以及急性肝炎，提示HEV经输血传播的可能性。     

Prevalence of antibody against hepatitis E virus in various species of non-human primates: evidence of widespread infection in Japanese monkeys (Macaca fuscata)

We screened 495 serum samples from 20 species of non-human primates for the antibody against hepatitis E virus (HEV). Anti-HEV IgG was detected in 84 of 232 (36.2%) Japanese monkeys, 2 of 19 (10.5%) cynomolgus monkeys, 3 of 83 (3.6%) rhesus monkeys, and 1 of 1 (100%) Taiwanese monkey, respectively. These results suggest that HEV is circulating among monkeys belonging to the genus macaca. A high prevalence of anti-HEV IgG was observed in Japanese macaques (M. fuscata) despite the fact that Japan is non-endemic for hepatitis E. It is possible that HEV can be transmitted from Japanese macaques to humans. Further, the rate of antibody positivity was found to increase with age in Japanese macaques. Seropositive macaques were found throughout Japan, but the seroprevalence rate differed among geographic regions.     

Failure to infect rhesus monkeys with hepatitis C virus strains of genotypes 1a, 2a or 3a

The chimpanzee is the only recognized animal model for the study of hepatitis C virus (HCV). However, recently it was reported that rhesus monkeys were susceptible to HCV and developed hepatitis during infection. In the present study, we inoculated two rhesus monkeys each with HCV strain H77 (genotype 1a), strain HC-J6 (genotype 2a) or strain S52 (genotype 3a). Weekly serum samples were tested for liver enzyme values, HCV antibodies and HCV RNA. We did not find evidence of HCV infection in any of the monkeys during 24 weeks of follow-up. Our study demonstrates that rhesus monkeys are not readily infected with HCV and apparently do not represent a useful animal model for the study of HCV.     

Human and swine hepatitis E viruses from Western India belong to different genotypes

BACKGROUND/AIMS: Hepatitis E is endemic in India. Earlier, we showed prevalence of IgG antibodies to hepatitis E virus (IgG-anti-HEV) in different animal species and inability of at least one human hepatitis E virus (HEV) strain to infect pigs. In the US where hepatitis E is not endemic in humans, zoonotic spread of HEV was suspected as swine and human HEV were closely related and cross-species infection was documented. The present study attempts to identify and partially characterize swine HEV from India. METHODS: Serum samples from 284 pigs were screened for the presence of HEV-RNA (nested polymerase chain reaction; PCR) and IgG-anti-HEV (enzyme-linked immunosorbent assay; ELISA). PCR products (Open Reading Frame-2 region) were sequenced and subjected to phylogenetic analysis. Two sero-negative pigs were inoculated with swine HEV-positive serum pool. RESULTS: ELISA and PCR positivity were 42.9 and 4.6%, respectively. All Indian swine HEV sequences clustered with genotype IV. Pigs could be experimentally infected with swine HEV. CONCLUSIONS: Swine HEV circulates in Indian pigs. In contrast to US and Taiwan wherein both human and swine HEV isolates belong to same genotype, Indian human HEV isolates belong to genotype I whereas genotype IV circulates in swine. Though experimental infection with Indian swine HEV was possible, at least one human HEV strain could not infect pigs.     

Prevalence of hepatitis E virus in Egyptian children presented with minor hepatic disorders

Hepatitis E virus (HEV) is considered as one of the common causes of particular hepatitis in developing countries. It is transmitted in a fecal-oral manner. It causes sporadic infections and large epidemics. To estimate the prevalence of anti-HEV IgG and IgM antibodies to ORF3 peptide of Hepatitis E virus genome in an age of children, study subjects (100 children) between 6 months and 10 years with minor, hepatic illnesses were recruited for the study during the period from September 2004 to September 2005. Serum anti-HEV IgG and anti-HEV IgM antibodies were screened in all subjects, anti-HEV IgM antibodies were assayed as an indicator of recent infection. Serum transaminases (AST and ALT) were estimated in positive subjects. Out of 100 subjects recruited, 26 subjects (26%) demonstrated anti-HEV IgG and 6 (6 %) were anti-HEV IgM and IgG positive. Anti-HEV IgG were present since the first year of age till 10 years of age and increased with advancing age. Serum transaminases were raised in one (17%) of subjects with anti-HEV IgM antibodies. CONCLUSIONS: Children are susceptible to HEV infection since early infancy. Seropositivity to HEV antibodies increased by over 2 times beyond 4 years of age as compared to younger age.     

庚型肝炎病毒基因组RNA的实验转染

目的：研究庚型肝炎病毒（HGV）对恒河猴的致病性及其在恒河猴体内的复制和表达。方法：体外转录制备全长HGV基因组RNA，肝内注射感染BY1猴，9个月后取其阳性血清感染BM1猴，7个月后取BM1阳性血清感染BB1。采用RT－PCR、原位杂交、定量PCR和免疫学、血清酶学、组织病理学等方法，对HGV的感染性及致病性进行了研究。结果：BY1、BM1和BB1实验猴感染后，分别在第3、8和3周血清HGV RNA阳转，持续存在最长达21周。血清丙氨酸转移酶（ALT）均升高，最高达418IU／L。感染后血清中均检测出抗－HGV。肝组织检查呈现轻度肝炎样变，并检测到HGV mRNA和HGV E2蛋白在肝组织中的表达。结论：体外转录的HGV基因组RNA对恒河猴具有感染性，可在恒河猴中传代感染并引起肝组织轻微炎症改变。恒河猴对HGV感染敏感，可作为研究HGV的实验动物模型。     

Transmission of enteric non-A, non-B hepatitis virus in Macaca mulatta, monkeys by intraportal route: Subsequent passages of HEV virus

Macaca mulatta monkeys have been used for the transmission of enteric non-A, non-B hepatitis (HEV) virus by intraportal route. Subsequent passages of HEV virus have been completed in these monkeys. In the first passage, 2 monkeys were inoculated by intra-portal route with 27-34 nm virus-like particles (VLP) obtained from known epidemics of HEV hepatitis in India, and biochemical and serological changes in the blood, histological changes in the liver and excretion of 27-34 nm VLP in the stool were studied. Results were compared with those of 4 negative control monkeys inoculated with stool extracts from healthy individuals. The second passage of 27-34 nm VLP was carried out on 2 monkeys using pools of stool suspension positive for 27-34 nm VLP from first passaged animals. Similarly, the third passage of 27-34 nm VLP was completed intraportally in another monkey. All monkeys developed acute hepatitis, as evidenced by transient elevation of aminotransferase, histopathological changes in the liver, development of antibodies aggregating 27-34 nm VLP and excretion of 27-34 nm VLP in stools. No control monkeys developed these features.     

Protective efficacy of hepatitis E virus DNA vaccine administered by gene gun in the cynomolgus macaque model of infection

The protective efficacy of a DNA vaccine against hepatitis E virus (HEV) infection was tested in cynomolgus macaques (cynos) vaccinated with a plasmid containing a full-length HEV open-reading frame 2 (ORF2) sequence (Burmese strain) and subsequently challenged with a heterologous strain of HEV (Mexican strain). Cynos administered vaccine by gene gun developed antibodies to HEV (anti-HEV), whereas cynos administered vaccine by intradermal injections and cynos administered a mock DNA construct did not develop anti-HEV. Anti-HEV-positive cynos were protected from HEV infection after challenge with an inoculum that produced infection in the anti-HEV-negative cynos. These results indicate that DNA vaccine with HEV ORF2 administered by gene gun is protective against a heterologous viral challenge.     

Interactions between simian immunodeficiency virus and Mycobacterium leprae in experimentally inoculated rhesus monkeys

Thirty-four rhesus monkeys were inoculated with Mycobacterium leprae inoculum isolated from sooty mangabey monkeys with leprosy. Later it was learned that one of the M. leprae-donor mangabeys was asymptomatically infected with simian immunodeficiency virus (SIV). Thus, five of the rhesus monkey were coinoculated with M. leprae and SIV. Three of the five became SIV-positive and developed signs of leprosy and an AIDS-like illness. Two animals remained healthy. The coinoculated leprosy-positive rhesus monkeys developed leprosy despite serologic response patterns to M. leprae antigens that usually indicate leprosy resistance. Three (60%) of the five SIV-positive rhesus monkeys developed leprosy compared with 21% of the animals who received SIV-free M. leprae inocula. Diminished lepromin skin test responses and decreasing T-helper cell percentages were observed in SIV-coinoculated rhesus monkeys with leprosy. These observations suggest that SIV increases the susceptibility of rhesus monkeys to leprosy, possibly related to loss of T-helper cell function.     

献血员戊型肝炎病毒亚临床感染情况调查

目的了解献血员中戊型肝炎病毒(HEV)亚临床感染情况。方法对2002年7～8月向北京市血液中心义务献血的所有人员进行整群抽样，检测抗-HEV IgM和IgG抗体。结果北京献血员中抗-HEV IgM阳性率为1．74％，其丙氨酸氨基转移酶(ALT)异常比例高于抗-HEV IgM阴性献血员。ALT异常与HEV相关的比例为2．68％，与HBV相当，但高于丙型肝炎病毒。结论献血员中存在HEV亚临床感染者，并且是献血员中ALT异常的原因之一。     

Kinetic study of platelets and fibrinogen in Lassa virus-infected monkeys and early pathologic events in Mopeia virus-infected monkeys

The rhesus monkey, an established model of Lassa fever, was used to study hematologic and hemostatic aspects of Lassa fever and whether Mopeia (also known as Mozambique) virus induces any cellular damage in this model. Six days after subcutaneous injection of 10(3.48) plaque forming units (PFU) of Lassa virus (Josiah strain) one group of monkeys received an intravenous injection of 111In-labeled allogeneic platelets and another group received 125I-labeled alogeneic fibrinogen. Lassa virus-infected monkeys developed a severe clinical illness with high viremia and typical pathology. Lassa antigen was found in most tissues using a Lassa nucleocapsid-specific monoclonal antibody. Platelet counts remained within normal limits. Platelet and fibrinogen kinetics were similar in infected and control animals. Hematologic and hemostatic changes indicate that disseminated intravascular coagulation plays no role in this model of Lassa fever. Levels of plasma fibronectin were reduced in Lassa-infected monkeys. Mopeia virus-infected monkeys were normothemic, aviremic, and there was no detection of Mopeia antigen in any tissues using polyclonal or monoclonal antibodies. Mopeia virus was recovered from the spleen of one monkey. Mopeia virus was associated with hepatocellular and renal tubular damage.