Faecal shedding of hepatitis-A antigen

Growth of hepatitis A virus in a mouse liver cell line

Hepatitis A virus (HAV) has been adapted to grow efficiently in primate and some nonprimate cell lines but not in cells of murine origin. To understand the inability of the virus to grow in mouse cells, we studied the replication of HAV in immortalized and nontransformed MMH-D3 mouse liver cells, which require growth factors and collagen to maintain their phenotype. HAV grew in MMH-D3 cells transfected with virion RNA but not in those infected with viral particles, indicating a cell entry block for HAV. However, MMH-D3 cells cultured under suboptimal conditions in the absence of growth factors acquired susceptibility to HAV infection. Serial passages of the virus in MMH-D3 cells under suboptimal growth conditions resulted in the selection of HAV variants that grew efficiently in MMH-D3 cells cultured under both optimal and suboptimal conditions. Nucleotide sequence analysis of the MMH-D3 cell-adapted HAV revealed that N1237D and D2132G substitutions were present in the capsid regions of six viral clones. These two mutations are most likely located on the surface of the virion and may play a role in the entry of HAV into the mouse liver cells. Our results demonstrate that mouse hepatocyte-like cells code for all factors required for the efficient growth of HAV in cell culture.

Phylogenetic analysis of hepatitis A virus in Thailand

Human hepatitis A virus (HAV) is a major causative agent of acute hepatitis, and the isolates are categorised into four genotypes: I (GI), II (GII), III (GIII), and VII (GVII). Although viral hepatitis has been detected under a nationwide surveillance system in Thailand, the genetic variation of HAV has not yet been determined. In the present study, serum specimens were collected from acute hepatitis patients in Thailand from 1998-2002. The IgM-class antibody to HAV was detected in 156 out of 394 sera, counting as many as 39.6% of acute viral hepatitis cases. HAV RNA in the serum specimens was amplified by reverse-transcription polymerase chain reaction (RT-PCR), and a phylogenetic analysis of the putative VP1/2A junction of the genome was performed. The isolates were grouped into two genetic groups, GIA and GIB. This is the first report to identify subgenotype IB (GIB) in Thailand. The genetic segregation was closely related to the province where hepatitis A occurred and the serum specimens were collected. In addition, genetically similar strains were identified in both 1998 and 2001-2002 isolates from two close provinces in the southern part of Thailand, suggesting that a strain indigenous to the province or district has been circulating in southern Thailand.

Vertical transmission of hepatitis A

Two hospital delivered full term newborn babies were detected to have cholestatic jaundice in the first week of life. They had raised liver enzyme levels, which gradually declined over a period of one month. Both babies were anti HAV IgM positive on 6th day of life in Case 1 and on 7th day of life in Case 2 respectively. Both the mothers had jaundice 20 and 26 days before delivery and had anti HAV IgM positivity two and three weeks prior to delivery in Case 1 and 2 respectively. Hepatitis A virus is not transmitted vertically from mother to baby. However, there are 3 such case reports in literature stating vertical transmission of HAV infection. We are reporting it in two neonates for the first time in India.

Experimental hepatitis A virus (HAV) infection in Callithrix jacchus: early detection of HAV antigen and viral fate

Common marmosets (Callithrixjacchus) were orally inoculated with a Brazilian strain (HAF-203) of hepatitis A virus (HAy). Three monkeys were euthanized at postinoculation hours 6, 12 and 24 to investigate the early events of HAV infection. Following others three inoculated and one control marmosets remained throughout the 46 day to evaluation of viral excretion. Different samples were collected to detect sequential presence of HAV RNA by nested reverse transcription-polymerase chain reaction (RT-PCR) in liver, saliva, bile and stools at 6 hours to 461h days postinoculation. Liver tissues were examined by immunofluorescence assay in a confocal laser-scanning microscope for the presence of HAV antigen. HAV RNA was detected in saliva during the course of the study, in bile from 24 hours to 46 days. in stools from 7 to 46 days and liver at 12 hours postinfection. In immunofluorescence of liver stained preparations, viral antigen was present at six hours after inoculation throughout the remainder of the 46-day study. The animals developed histological and biochemical acute hepatitis after second week postinoculation. Spleen, duodenum, and mesenteric lymph nodes specimens were negative for HAV antigens. This study supports the possibility that in Callithrixjacchus orally inoculated with hepatitis A virus the saliva route may be additional way of viral elimination. The viral replication in the liver was responsible for biliary HAV presence and latter HAV detection in fecal samples.

Evidence base of incubation periods, periods of infectiousness and exclusion policies for the control of communicable diseases in schools and preschools

BACKGROUND

The optimal control of communicable diseases requires accurate information on incubation periods, periods of infectiousness and the effectiveness of exclusion. We collected the available evidence for a wide range of infections and infestations and produced evidence-based guidelines for their control in schools and preschools.

METHODS

A thorough MEDLINE literature search was conducted on the incubation period, period of infectiousness and effectiveness of exclusion for 41 infections. The quality of the information obtained was indicated by levels of evidence. The information was used to produce guidelines on exclusion, and the recommendations were graded according to the levels of evidence available. Grades A, B and C represented strongly, reasonably and poorly evidence-based recommendations, respectively.

RESULTS

The quality of data obtained was highly variable. Information on incubation periods was obtained for all 41 infections and was generally of good quality. Information on periods of infectiousness and effectiveness of exclusion was of a lesser quality and was found for only 11 and 4 conditions, respectively. There were 3 Grade A, 17 Grade B and 21 Grade C recommendations on exclusion. Examples of exclusion periods include: 5 days for chickenpox, measles, mumps, rubella, pertussis and scarlet fever; and 24 h from the cessation of diarrhea for most gastrointestinal diseases In contrast to existing guidelines exclusion was not recommended for school age children with hepatitis A.

CONCLUSIONS

We have been able to present the best available data on the incubation periods and periods of infectiousness of 41 childhood infections. It was possible to produce strongly or reasonably evidence-based guidelines on exclusion periods for approximately one-half of the infections.

Hepatitis A: old and new

The hepatitis A virus (HAV), a picornavirus, is a common cause of hepatitis worldwide. Spread of infection is generally person to person or by oral intake after fecal contamination of skin or mucous membranes; less commonly, there is fecal contamination of food or water. Hepatitis A is endemic in developing countries, and most residents are exposed in childhood. In contrast, the adult population in developed countries demonstrates falling rates of exposure with improvements in hygiene and sanitation. The export of food that cannot be sterilized, from countries of high endemicity to areas with low rates of infection, is a potentially important source of infection. After ingestion and uptake from the gastrointestinal tract, the virus replicates in the liver and is excreted into the bile. Cellular immune responses to the virus lead to destruction of infected hepatocytes with consequent development of symptoms and signs of disease. Humoral immune responses are the basis for diagnostic serologic assays. Acute HAV infection is clinically indistinguishable from other causes of acute viral hepatitis. In young children the disease is often asymptomatic, whereas in older children and adults there may be a range of clinical manifestations from mild, anicteric infection to fulminant hepatic failure. Clinical variants include prolonged, relapsing, and cholestatic forms. Management of the acute illness is supportive, and complete recovery without sequelae is the usual outcome. Research efforts during World War II led to the development of passive immunoprophylaxis. Pooled immune serum globulin is efficacious in the prevention and attenuation of disease in exposed individuals. More recently, active immunoprophylaxis by vaccination has been accomplished. Future eradication of this disease can now be contemplated.

Cost effectiveness of vaccinating food service workers against hepatitis A infection

Foodborne transmission is an important means of hepatitis A infection that may be reduced through vaccination of food service workers (FSWs). Several states are considering actions to encourage or mandate FSW vaccination, but the cost effectiveness of such policies has not been assessed. We estimated the clinical and economic consequences of vaccinating FSWs from the 10 states with the highest reported rates of hepatitis A. A decision analytic model was used to predict the effects of vaccinating FSWs at age 20 years. It was assumed all FSWs would receive one dose of inactivated hepatitis A vaccine, and 50% would receive the second recommended dose. Parameter estimates were obtained from published reports and Centers for Disease Control and Prevention databases. The primary endpoint was cost per year of life saved (YOLS). Secondary endpoints were symptomatic infections, days of illness, deaths, and costs of hepatitis A treatment, public health intervention, and work loss. Each endpoint was considered separately for FSWs and patrons. We estimate vaccination of 100,000 FSWs would cost $8.1 million but reduce the costs of hepatitis A treatment, public health intervention, and work loss by $3.0 million, $2.3 million, and $3.1 million, respectively. Vaccination would prevent approximately 2,500 symptomatic infections, 93,000 days of illness, and 8 deaths. A vaccination policy would reduce societal costs while costing the health system $13,969 per YOLS, a ratio that exceeds generally accepted standards of cost effectiveness.

Studies on transmission of hepatitis A virus to squirrel monkeys

Non-human primates have been playing an essential role in the study of hepatitis A virus (HAV) biology, pathogenesis and for testing candidate HAV vaccines. This study was to determine the suitability of squirrel monkeys (Saimiri sciureus) as animal model for HAV infection. Animals were inoculated, either intragastrically or intravenously, with a Brazilian HAV isolate (HAF-203). Alanine aminotransferase (ALT) and anti-HAV antibodies (IgM and total) were monitored. Feces were daily collected for HAV antigen and HAV RNA detection. Samples of liver tissue were obtained by biopsy before inoculation at peak ALT levels and/or when anti-HAV antibodies developed, and at necropsy for morphological examination. Monkeys inoculated by the intravenous route rapidly developed significant elevations of serum ALT, anti-HAV antibodies, and liver histologic changes, while the only evidence of HAV infection in intragastrically inoculated animals was the seroconversion. Moreover, squirrel monkeys excreted very low levels of HAV detectable in only few fecal samples after amplification by RT-PCR, different from humans and other non-human primate species that eliminate large quantities of virus during the late incubation period. The unusual onset of hepatitis A in experimentally infected squirrel monkeys represent an important obstacle for its use as animal model for the study of this viral infection. However, they can represent a valuable tool for the obtention of hyperimmune sera for HAV, in the view of the very high titer of anti-HAV developed (10⁵) 24 days after a single intravenous inoculation.

Excretion of hepatitis A virus (HAV) in adults: comparison of immunologic and molecular detection methods and relationship between HAV positivity and infectivity in tamarins

Fecal excretion of hepatitis A virus (HAV) in 18 patients with HAV infection was evaluated by enzyme immunoassay (EIA) to detect viral antigen and by reverse transcription-PCR amplification followed by ethidium bromide staining (PCR-ETBr) or nucleic acid hybridization (PCR-NA) to detect viral genetic material. A gradation of sensitivity was observed in the detection of virus by the three methods. In persons who had detectable virus, serial stool samples were found to be positive by EIA for up to 24 days after the peak elevation of liver enzymes. Viral genetic material could be detected by PCR-ETBr for up to 34 days and by PCR-NA for up to 54 days after the peak elevation of liver enzymes. After intravenous inoculation of tamarins with stool suspensions categorized as highly reactive for HAV (positive by EIA, PCR-ETBr, and PCR-NA), moderately reactive (positive by PCR-ETBr and PCR-NA), or weakly reactive (positive by PCR-NA), only tamarins infected with highly reactive stool suspensions (EIA positive) developed HAV infection. We conclude that positivity of stool specimens for HAV by PCR-ETBr or PCR-NA indicates a lower potential for infectivity, compared to that of EIA-positive stools.

The risks of transmission of acute hepatitis A and B virus infection in an urban centre

In a large urban centre of a developed nation, 63 household contacts of 20 index cases with acute hepatitis A virus infection and 95 household contacts of 29 index cases with acute hepatitis B virus infection were prospectively followed for 2 years to document the risk of acquiring acute hepatitis from the index case. Twenty-one of 63 (33%) hepatitis A virus household contacts had serologic evidence of previous hepatitis A virus infection on the initial serum sample. Of the remaining 42 susceptible individuals, 22 (52%) were or became IgM anti-HAV positive within 6 months of the diagnosis in the index case. With respect to hepatitis B virus infection, 18/95 (17%) household contacts had serologic evidence of previous hepatitis B virus infection on the initial serum sample. Of the remaining 77 susceptible individuals, four (5%) had or developed serologic evidence of acute hepatitis B virus infection (IgM anti-hepatitis B core antigen positive) during the 2 years of follow up. In three of these four individuals, acquisition of hepatitis B virus was apparent within 6 months of the diagnosis in the index case. The results of this study indicate that in this urban centre, the risk of acquiring acute hepatitis A virus infection from index cases within the household is approximately 10 times greater than that for acute hepatitis B virus infection. These results support the need for continued passive and/or active immunization against hepatitis A and B virus infection in susceptible household contacts.

Serum IgA anti-hepatitis A virus as detected by enzyme-linked immunosorbent assay. Diagnostic significance in patients with acute and protracted hepatitis A

A capture enzyme-linked immunosorbent assay for the detection of serum IgA against hepatitis A virus has been developed. The test was highly specific, and the time course of detectability of IgA anti-HAV was longer than six months in 42/42 patients with acute or protracted hepatitis A followed prospectively, but shorter than two years in 14/14 patients tested 21-24 months after diagnosis of acute hepatitis A. IgM anti-HAV were at detectable levels in only 1/42 cases tested six months after the clinical onset. The detection of serum IgA anti-HAV is a simple and specific method to differentiate protracted cases of hepatitis A from non-A, non-B hepatitis.

Etiopathogenetic aspects of hepatitis A. I. Excretion of hepatitis A virus, biochemistry of liver function, and humoral immune response in patients with hepatitis A on admission to hospital

The excretion of hepatitis A virus (HAV) in stools from 30 patients with clinically overt hepatitis A infection on the day of their admission to the hospital was determined and compared with the dynamics and values of biochemical indices of hepatocyte injury as well as with the immune response to HAV. Virus was found in 16 out of 30 stools (53%) collected within 1 week after the appearance of clinical symptoms. In sera obtained on the day of hospitalization both IgM and IgA anti-HAV were detected in all of the 30 patients, while IgG anti-HAV were found in 20 (67%). There was a correlation between HAV excretion and increasing SGPT upon admission to hospital, while the level of SGPT or bilirubin as well as presence or absence of IgG anti-HAV did not correlate with excretion of HAV. HAV from stools was characterized morphologically and physicochemically. The majority of particles visualized by immune electron microscopy had electrondense appearance, while electron-lucid particles were only occasionally encountered. Isopycnic banding of HAV in CsCl revealed a broad range of densities with HAV activity. Rebanding of pooled fractions containing HAV revealed peak amounts of the virus in fractions with densities 1.32-1.33 gm/cm3.

Acute type A hepatitis during chronic hepatitis B virus infection: association of depressed hepatitis B virus replication with appearance of endogenous alpha interferon

Two patients with chronic type B hepatitis and intercurrent episodes of acute type A hepatitis are presented. Serological markers of hepatitis B virus replication decreased or became undetectable in both patients during the acute illness, while interferon activity was transiently detected in serum. The presence of serum leukocyte (alpha) interferon was confirmed by neutralization with specific antisera and tests of pH2 stability. These observations suggest a role for natural leukocyte (alpha) interferon in the modulation and control of hepatitis B virus infection and provide further evidence to support trials of exogenous leukocyte (alpha) interferon in the chronic infection.

Primary hepatocellular carcinoma following non-A, non-B posttransfusion hepatitis

In 1964 a 42-year-old woman was hospitalized with clinical and laboratory signs of posttransfusion hepatitis five weeks after administration of six whole blood transfusions. During the following 17 years anicteric chronic liver disease was repeatedly documented by elevations of serum aspartate aminotransferase (SGOT) and alkaline phosphatase enzymes. In 1981 hepatomegaly, progressive jaundice, and a serum alphafetoprotein level of 516,000 ng/ml were observed. Percutaneous liver biopsy showed a primary hepatocellular carcinoma (PHC). Serologic examinations failed to reveal markers for hepatitis B virus including HBsAg, anti-HBs, and anti-HBc by radioimmunoassay; antibody to hepatitis A virus was also absent. This sequence of events demonstrates a presumptive association of PHC and the agent(s) of non-A, non-B viral hepatitis.

Transmission of hepatitis A virus among recently captured Panamanian owl monkeys

The presence of antibody to hepatitis A virus (anti-HAV) in 60% of procured owl monkeys (Aotus trivirgatus) held within the United States prompted a study of recently captured A trivirgatus in Panama. Only 2 of 145 newly captured monkeys, but all of 35 A trivirgatus held within a colony for over 100 days, were found to have anti-HAV. Of 41 sero-negative, newly captured monkeys followed prospectively, 25 became infected with hepatitis A virus (HAV) as evidenced by seroconversion or demonstration of virus in the liver at death. Only one monkey that survived over 60 days within the colony was not infected. HAV was identified in the feces of most infected monkeys prior to the development of antibody and was antigenically indistinguishable from human HAV in cross-blocking radioimmunoassays. This colony-centered epizootic provides strong evidence that A trivirgatus is susceptible to HAV and should be investigated further as a potential model of human hepatitis A.

Excretion of hepatitis A virus in the stools of hospitalized hepatitis patients

A study was carried out to determine whether hepatitis A virus (HAV) can be detected in the stools of patients hospitalized for HAV infection. Acute phase samples of whole blood and stool, as well as completed questionnaires, were obtained from 31 patients hospitalized at any of 13 hospitals in the Phoenix metropolitan area. Blood specimens were tested for hepatitis B surface antigen (HBsAg), IgG antibody to HAV (IgG anti-HAV), and IgM antibody to HAV (IgM anti-HAV). Stools were tested for HAV by radioimmunoassay. Five patients (16.1%) had acute hepatitis B, five (16.1%) had acute non-A/non-B hepatitis, and 21 (67.7%) had acute hepatitis A. Of these 21 patients with acute hepatitis A, 11 (52.4%) were found to have HAV in their stools. These results confirm the potential for infectivity of stools of patients hospitalized for hepatitis A and emphasizes the need for caution when dealing with such stools.

Hepatitis A virus: virologic, clinical, and epidemiologic studies

The last decade has borne witness to accelerated expansion of our understanding of hepatitis A virus. The agent of type A hepatitis is an RNA virus with a mean diameter of 27 nm. and biochemical-biophysical properties of an enterovirus. A variety of sensitive specific serologic techniques have been developed with which to identify hepatitis A virus and antibody, and both chimpanzees and marmosets have been studied extensively as experimental animal models. As a result of these studies, in vitro cultivation of hepatitis A virus has finally been accomplished, and a commercial radioimmunoassay for IgM antibody to hepatitis A virus has been developed for the rapid diagnosis of hepatitis A virus infection during acute illness. Clinically the illness caused by hepatitis A virus is relatively mild, often subclinical, and of limited duration and does not progress to chronic liver disease. This relative clinical benignity is reflected, according to preliminary histologic observations, in the sparing of the centrozonal area of the liver lobule. Rarely, however, hepatitis A virus can cause fulminant hepatitis. Type A hepatitis is transmitted almost exclusively by the fecal-oral route, and its spread is enhanced by epidemiologic settings favoring dissemination of enteric infections. Hepatitis A virus does not contribute to transfusion associated or other types of percutaneously transmitted hepatitis. Exposure to the virus increases as a function of age and decreasing socioeconomic class, but the incidence of hepatitis A virus infection in urbanized societies is decreasing. There is no evidence for the existence of chronic hepatitis A virus carriage; natural perpetuation of hepatitis A virus in urban communities appears to depend on a reservoir of nonepidemic, clinically inapparent cases. Until a vaccine, now being developed, becomes available, prevention of hepatitis A virus infection will continue to depend on maintenance of high standards of environmental and personal hygiene and on timely administration of immune serum globulin. Such prophylaxis may confer long lasting passive-active immunity but more frequently prevents infection entirely.

Immunoprophylaxis of viral hepatitis

Emergency physicians frequently encounter patients who have been or may have been exposed to viral hepatitis, and are often in a position to offer immunoprophylaxis. Needlestick exposure among hospital employees is endemic in any large hospital. Currently treatment of clinical hepatitis is only symptomatic; rational immunoprophylaxis is the only method available to influence the course of the disease. The basic types of viral hepatitis are reviewed, as are transmission of the disease, serologic tests, high risk groups, and immunoprophylactic agents. Treatment plans are outlined for different types of exposure, and an algorithm is included for management of needlestick exposure.

Serodiagnosis of viral hepatitis A by a solid-phase radioimmunoassay specific for IgM antibodies

A solid-phase radioimmunoassay for detecting specific IgM antibodies to hepatitis A virus (HAV) was developed and characterized. The test utilized microtiter plates coated with anti-IgM to specifically absorb the IgM antibodies from the test serum. The anti-hepatitis A IgM antibodies are measured by the specific consecutive binding of hepatitis A antigen and radiolabelled anti-hepatitis A antibodies (anti-HA). In 6 chimpanzees infected with HAV, IgM anti-HA was detected from about the first date of elevated transaminases and was positive for about 3 months. The usefulness of the test was confirmed by testing acute phase sera of 30 patients from a common source outbreak of epidemic hepatitis, and negative sera from 2 control groups. A collection of serum specimens from 190 patients with sporadic HBsAg-negative hepatitis in Brazil was also tested and an etiologic association with HAV was confirmed in the majority of these cases.

Hepatitis A virus infection: pathogenesis and serodiagnosis of acute disease

The early development of immune electron microscopic (IEM) methods for the detection of HAV in acute-phase stool suspensions and antibody to HAV (anti-HAV) in serum made it possible to serologically identify cases of hepatitis A using paired acute and convalescent phase sera. Introduction of less cumbersome and time-consuming serologic test methods, including complement fixation (CF) and immune adherence hemagglutination (IAHA), made it feasible to rapidly assay larger numbers of specimens for HAV or anti-HAV. Subsequent development of sensitive immunofluorescence (IF) assays, solid-phase radioimmunoassays (RIA), and enzyme immunoassays (EIA) for HAV and anti-HAV heralded intensive laboratory studies of the biophysical and biochemical properties of the virus as well as efforts to define the pathogenesis and clinical course of disease. Results of the latter studies showed that the bulk of HAV was usually excreted in stool before the onset of clinical symptoms. Other serologic studies demonstrated that all acutely ill patients had circulating anti-HAV IgM, while all convalescent patients were positive for anti-HAV IgG. The development of sensitive serologic tests (RIA and EIA) that could differentiate between anti-HAV IgM and IgG made it possible to serodiagnose an acute case of hepatitis A using a single-phase serum specimen.

Epidemiology of hepatitis A in Amsterdam, October 1978--December 1979

The epidemiology of hepatitis A was studied in Amsterdam during a 15 month period from October 1978 through December 1979. 349 cases of viral hepatitis were reported of which 135 were serologically identified as hepatitis A. The diagnosis was established by testing a single acute-phase serum sample with ELISA for the detection of hepatitis A IgM antibodies. Most cases were sporadic; there were no outbreaks involving more than three cases. A seasonal variation was recognized with the highest incidence in later autumn and early winter. The peak attack rate was found in the age group of 5--9 and a smaller peak was noticed in the age group of 30--34. Recent exposure to a known case of hepatitis A or to a jaundiced person was the probable source of infection in 27% of the patients; 23% contracted hepatitis A within 7 weeks of visiting a tropical or subtropical country and in 50% no source was found. 50 patients provided stool specimens within 2 weeks of the onset of jaundice. Specimens were examined for the presence of hepatitis A virus antigen by ELISA and seven patients had positive stools, all within the first week of the onset of jaundice.

Seroepidemiology of viral hepatitis: correlation with clinical findings

Antibody to hepatitis A antigen (anti-HA) is detectable in the serum shortly after infection with hepatitis A virus. The presence of IgM antibody indicates acute infection; IgG signifies past infection. Hepatitis B surface antigen (HBsAg) indicates infectiousness and is usually present when hepatitis B virus causes active liver disease; its antibody (anti-HBs) is neutralizing and confers immunity. Antibody to core antigen (anti-HBc) is an index of hepatitis B viral replication when present in high titers; in low titers it reflects past infection. Early presence of e antigen (HBeAg) indicates a high degree of infectivity, whereas presence of its antibody (anti-HBe) indicates a lesser degree. Although markers of non-A non-B hepatitis have been described, the definitive nature and number of the virus or viruses are not yet clear.

Nosocomial viral infections: II. Guidelines for prevention and control of respiratory viruses, herpesviruses, and hepatitis viruses

This article reviews the most likely mechanisms of transmission of the commonly encountered respiratory viruses (influenza, respiratory syncytial virus, parainfluenza, rhinovirus), herpesviruses, and hepatitis viruses, and presents the guidelines used currently for prevention and control that are in use at Strong Memorial Hospital.

Hepatitis A virus in the liver and intestine of marmosets after oral inoculation

A total of 12 seronegative marmosets (Saguinus mystax) were inoculated orally with hepatitis A virus (HAV) and sacrificed at 3- to 4-day intervals. Tissues from the livers, intestines, mesenteric lymph nodes, and spleens were obtained for immunofluorescence studies, and bile and intestinal contents were obtained for enzyme-linked immunosorbent assay studies. Two marmosets sacrificed on days 34 and 41 after inoculation developed antibody to HAV and demonstrated HAV in their livers but not in any part of their intestinal tissues. None of the remaining marmosets sacrificed from days -3 to 31 survived long enough to develop antibody to HAV, but an additional two marmosets, which were sacrificed on days 21 and 31, demonstrated HAV in their livers and also in bile but not in the intestinal tissues or their contents. The mesenteric lymph nodes and spleens were negative for HAV by immunofluorescence in all the marmosets. No evidence of HAV replication was demonstrated in any part of the intestine at any time during the incubation period or during acute illness in the marmosets inoculated orally with HAV. The shedding of HAV in stools in the late incubation period can be explained by excretion of HAV from the livers with the bile.

Non-A, non-B hepatitis in patients receiving blood products

A group of patients all regularly receiving blood products for a congenital bleeding disorder were investigated for evidence of past infection with hepatitis A and B, and compared with a control group. There was a significantly higher percentage of the test group who had markers of infection with these viruses, and 15 patients had symptoms of hepatitis during the study. The greater number of the test group showing evidence of past hepatitis A infection can only really be explained by acquiring antibody from blood products, especially since none of our patients with hepatitis had hepatitis A and there is evidence that this is not an infection associated with blood products. We conclude that the majority of patients in our study showing symptoms of hepatitis had non-A, non-B hepatitis.

Hepatitis A diagnosis in man: radioimmunoassay for hepatitis A antigen detection in faeces

A new radioimmunoassay (RIA) procedure using a double-sandwich technique was developed for the detection of hepatitis A antigen (HAV) in crude faecal extracts for patients involved in three outbreaks of type A hepatitis. Stools were obtained from 24 residents suffering from acute hepatitis A and from six children who remained asymptomatic throughout the epidemic. In addition, the HAV detection was performed in sera from 13 patients with hepatitis. HAV was detected in stools as early as five days before and as late as five days after the onset of jaundice. In this procedure, positive activity was only found in stools from patients with type A hepatitis, but not in negative controls. HAV was not detected in acute-phase sera. The double-sandwich RIA test used appears to be a reliable test for the large-scale screening of HAV in stool samples from patients suffering from type A hepatitis.

A radioimmunoassay for hepatitis A antigen and antibody

The HAVAB radioimmunoassay for the detection of antibody to hepatitis A is assessed. Its modification to detect virus in faecal samples is described and in this it was found to be more sensitive and specific than electron microscopy.

Pathogenesis of mouse hepatitis virus infection. The role of nasal epithelial cells as a primary target of low-virulence virus, MHV-S

The pathogenesis of mouse hepatitis virus (MHV‐S) infection in suckling and weanling mice was comparatively studied after intranasal inoculation. In sucklings, infectious virus as well as specific antigen was first detected in the nasal mucosa at 12 hr, then in the nerve cells of the olfactory bulbs. At this stage viral particles were demonstrated both in the supporting cells and olfactory cells of the nasal mucosa. In the posterior part of the brain and spinal cord, virus was detected on days 3 to 4 postinoculation when viral growth was clearly demonstrable in the liver, spleen and intestines. In weanlings too, infection was first established in the nasal mucosa, shedding infectious virus in the nasal washing until day 6 postinoculation, and later infection spread to the brain and spinal cord. In weanling mice, however, neither infectious virus nor viral antigen was detected in the liver or other visceral organs, while serum neutralizing antibody became detectable on day 5 postinoculation, increasing in titer thereafter. Histopathologically degenerative and necrotic changes were observed in the nasal mucosa and central nervous system of both age groups of animals coincidentally with the presence of viral specific antigen, while inflammatory response was much less prominent in sucklings. In the liver, spleen and intestines, however, some lesions were observed only in sucklings.

Hepatitis types A, B, and non A--non B in childhood

199 children with acute hepatitis hospitalized between 1968 and 1978 were tested for serological markers of hepatitis A and B infection. In 24 out of 28 HBsAg-positive patients, hepatitis B infection was diagnosed because of the disappearance of the antigen during convalescence. The histories of the 171 HBsAg-negative children suggested acute hepatitis A infection in 69% of the patients. This diagnosis could be confirmed in 110 of the 116 tested cases (95%) by a more than fourfold increase in the anti-HAV titer or by detection of anti-HAV of the IgM class. In the 55 HBsAg-negative patients without epidemiological clues as to the type of hepatitis, 40 children exhibited anti-HAV which could be related to acute A infection in 21 out of 22 tested cases. At least 11 patients had to be classified as having nonn A--non B infection. The results indicate that a combination of evaluation of the patient's history and selected serological tests will permit a fast preliminary diagnosis. This is important in the clinical management of patients and protection of contacts with immunoglobulin.

Studies on the outbreak of hepatitis A in an institute for mentally retarded children

The authors encountered an outbreak of acute hepatitis in a public institute for mentally retarded children in Aomori Prefecture, Japan. Studies revealed that the probable vehicles of transmission of infection were contaminated water, contaminated meals, and close contact. From the clinical manifestations and epidemiological investigations of 41 affected children and staff members, an outbreak of hepatitis A was strongly suspected. Immune electron microscopy disclosed hepatitis A virus antigen particles in the stool specimens collected during the few days before and after peak transaminase elevation. Hepatitis A antigen was further extracted and purified. The antigen was the first reported recovery of the virus from a natural outbreak of hapatitis A in Asia. Subsequently, with the immune adherence hemagglutination test, using this extracted antigen, an increase in titer of antibody to hepatitis A antigen was demonstrated. Thus, this epidemic was serologically established as an outbreak of hepatitis A. Human immune serum globulin for the protection against hepatitis A was administrated to the 80 individuals concerned, and it was effective in preventing the clinical manifestation of hepatitis.

A preliminary serologic study of hepatitis A virus infection in Japan

Ninety-eight acute non-B hepatitis cases recently observed in Japan and household contacts with these cases were subjected to serologic examinations for hepatitis A; 400 serum specimens obtained in 1971 from healthy individuals living in areas near Tokyo and 16 preparations of human immunoglobulin produced in Japan in 1975 and 1976 were examined for antibody to hepatitis A antigen. Hepatitis A virus infection was confirmed in all 25 patients and in 8 of 26 household contacts found in association with non-B hepatitis outbreaks, and also in 11 of 60 sporadic non-B hepatitis patients, but in none of 13 non-B hepatitis patients found in association with blood transfusion. There was no difference between males and females in the prevalence of antibody to hepatitis A antigen among healthy individuals, however, there was a strong relationship to age. Rates of antibody positives were only 2.5% in the groups younger than 20 years of age. An ample amount of antibody to hepatitis A antigen was detected in the preparations of human immunoglobulin. Hepatitis A virus was thus found to be endemic in Japan, but considered not popular during at least these 20 years. Infection with non-A non-B hepatitis virus(es) seems to be common in Japan especially in such cases as sporadic non-B hepatitis or post-transfusion non-B hepatitis.

Hepatitis A-virus particles in stools of patients from a natural hepatitis outbreak in Germany

During a hepatitis outbreak in Southern Germany 27 nm particles were visualized by immune electron microscopy in stools of two patients. These particles were sereologically identical or similar to hepatitis A-virus particles identified in the USA. The buoyant density of these particles was 1.34 g/cm3 as shown by cesium chloride density centrifugation. The particles were first observed in small numbers in a stool obtained 11 days, and in large numbers in stools obtained 6 and 7 days before the onset of jaundice. Few particles were seen on the day of the onset of jaundice and none thereafter. In both patients a sereoconversion to hepatitis A-virus as judged by immune electron microscopy could be demonstrated.

[Production of interferon and alpha 2-macroglobulin involvement in immune response during human viral hepatitis A (author's transl)]

In viral hepatitis A, we could distinguish between monophasic and polyphasic forms. Monophasic and polyphasic hepatitis A induce the production of plasma interferon. Interferon level, elevated as early as the first days following the appearance of clinical signs, decreases and reaches a minimum value on the seventh day. A new rise of interferon is characterized by a maximum level on the twelfth day and a minimum level on the thirtieth. Beyond the first month we could still detect the presence of interferon. In the two forms of hepatitis, a complement system is activated both by classical and alternate pathways. IgM levels increase early, IgA levels remain unchanged. On the other hand, IgG levels, only slightly elevated in monophasic hepatitis A, are highly increased in polyphasic hepatitis A beyond the first month. Alpha 2-macroglobulin reaches levels above normal during convalescence in monophasic hepatitis A; on the contrary, in polyphasic hepatitis A, alpha 2-macroglobulin levles are above normal as early as the thirty first days of illness and remain above normal for several months. Elevated levels in alpha 2-macroglobulin may inhibit cellular immunity which is accountable for immunological injury of virus infected hepatocytes. We wonder whether this earlier increase in alpha 2-macroglobulin is responsible for the lasting character of viral infection observed in polyphasic hepatitis A.

Cyclic excretion of hepatitis A virus in experimentally infected chimpanzees: biophysical characterization of the associated HAV particles

Experimental infection of two chimpanzees with the Phoenix Antigen strain of HAV resulted in the cyclic excretion of virus particles on days 9-11, 14-15, and 20-21 postinoculation. Isopycnic banding in CsCl of stool suspensions prepared from 9-11; 14-15; and 17, 19, 21 dav stool pools revealed multiple buoyant densities for the associated HAV particles. Hollow HAV particles found in the 9-11 day pool banded primarily at a buoyant density of 1.30 g/cm3. HAV in the 14-15 day stool banded bimodally in a CsCl gradient, with antigen peaks at buoyant densities of 1.29 and 1.33 g/cm3. HAV in the days 17, 19, 21 stool pool also banded bimodally in a CsCl gradient; however, the antigen peaks occurred at buoyant densities of 1.33 and 1.40 g/cm3.

Multiple buoyant densities of hepatitis A virus in cesium chloride gradients

Hepatitis A virus (HAV) recovered from stools of human cases of hepatitis A and from stools of chimpanzees experimentally infected with HAV was shown to possess multiple buoyant densities in CsCl gradients. The greatest proportion of HAV was most frequently found at a buoyant density of 1.32-1.34 g/cm3, however, large proportions of HAV were also frequently found at higher densities, including 1.36-1.37, 1.40-1.42, and 1.45-1.48 g/cm3. These findings are consistent with the notion that HAV may be a parvovirus.