A community outbreak of hepatitis A in a religious community in Indiana: failure of immune serum globulin to prevent the spread of infection.
(25/837)
An outbreak of hepatitis A occurred in a religious community in Indiana, USA. Sixty-nine cases were ascertained among the 4466 residents over a year, and the highest attack rate was in children. The management of the outbreak included the widespread use of prophylactic immune serum globulin (ISG). Despite this, further cases occurred. To guide further ISG administration, a survey was undertaken to ascertain what proportion remained susceptible to HAV infection. From a random sample of 600 people in the affected community 440 saliva specimens (73%) were obtained. Of these, 12.5% were found to be immune (95% confidence intervals from 9-16%). No changes were made to the ISG administration policy. There was no evidence to suggest that administration of ISG had any effect on the duration of the outbreak. There was a low rate of symptomatic infection among young children (less than 10 years); as ISG does not prevent the spread of the virus its use is not recommended in future outbreak situations. (+info)
Contamination of foods by food handlers: experiments on hepatitis A virus transfer to food and its interruption.
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Hepatitis A virus (HAV) is an important pathogen which has been responsible for many food-borne outbreaks. HAV-excreting food handlers, especially those with poor hygienic practices, can contaminate the foods which they handle. Consumption of such foods without further processing has been known to result in cases of infectious hepatitis. Since quantitative data on virus transfer during contact of hands with foods is not available, we investigated the transfer of HAV from artificially contaminated fingerpads of adult volunteers to pieces of fresh lettuce. Touching the lettuce with artificially contaminated fingerpads for 10 s at a pressure of 0.2 to 0.4 kg/cm(2) resulted in transfer of 9.2% +/- 0.9% of the infectious virus. The pretreatments tested to interrupt virus transfer from contaminated fingerpads included (i) hard-water rinsing and towel drying, (ii) application of a domestic or commercial topical agent followed by water rinsing and towel drying, and (iii) exposure to a hand gel containing 62% ethanol or 75% liquid ethanol without water rinsing or towel drying. When the fingerpads were treated with the topical agents or alcohol before the lettuce was touched, the amount of infectious virus transferred to lettuce was reduced from 9.2% to between 0.3 and 0.6% (depending on the topical agent used), which was a reduction in virus transfer of up to 30-fold. Surprisingly, no virus transfer to lettuce was detected when the fingerpads were rinsed with water alone before the lettuce was touched. However, additional experiments with water rinsing in which smaller volumes of water were used (1 ml instead of 15 ml) showed that the rate of virus transfer to lettuce was 0.3% +/- 0.1%. The variability in virus transfer rates following water rinsing may indicate that the volume of water at least in part influences virus removal from the fingerpads differently, a possibility which should be investigated further. This study provided novel information concerning the rate of virus transfer to foods and a model for investigating the transfer of viral and other food-borne pathogens from contaminated hands to foods, as well as techniques for interrupting such transfer to improve food safety. (+info)
Duration of viremia in hepatitis A virus infection.
(27/837)
The duration of viremia and time course for development of IgM antibodies were determined prospectively in natural and experimental hepatitis A virus (HAV) infection. Serial serum samples from HAV-infected men (n=13) and experimentally infected chimpanzees (n=5) were examined by nested reverse-transcriptase polymerase chain reaction analysis to detect HAV RNA and by ELISA to detect IgM antibodies to HAV. Among infected humans, HAV RNA was detected an average of 17 days before the alanine aminotransferase peak, and viremia persisted for an average of 79 days after the liver enzyme peak. The average duration of viremia was 95 days (range, 36-391 days). Results were similar in chimpanzees. In addition, HAV RNA was detected in serum of humans and chimpanzees several days before IgM antibodies to HAV were detected. These results indicate that adults with HAV infection are viremic for as long as 30 days before the onset of symptoms and that the duration of viremia may be longer than previously described. (+info)
Death in amphetamine users: causes and rates.
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The world medical literature contains 43 reports of deaths associated with amphetamines in a 35-year period. These included seven cerebrovascular accidents, six sudden cardiac deaths, three cases of hyperpyrexia, eight poisonings of uncertain mechanism and seven cases of medical complications of intravenous injection; the remainder were of uncertain cause. In contrast, in Ontario alone, in 1972 and 1973 there were 26 deaths in amphetamine users, of which 16 were due to accident suicide or homicide. Of the remaining cases, two were cardiac, two hepatic and the rest were mixed drug overdose. Pulmonary granulomata, subacute hepatitis and other lesions resulting from intravenous drug use were common findings at autopsy. On the basis of the estimated number of regular users of intravenous amphetamine in Ontario, the mortality rate in such users is at least four times as high as in the general population of the same age, and is comparable to that in alcoholics and heroin addicts. However, the absolute number of alcohol-related deaths is far greater than the number of deaths in amphetamine or heroin users. (+info)
Multiple modes of hepatitis A virus transmission among methamphetamine users.
(29/837)
Methamphetamine users are at increased risk of hepatitis A, but modes of transmission are unclear. The authors conducted a case-control study among methamphetamine users during an outbreak in Iowa in 1997. Twenty-eight reported, laboratory-confirmed, hepatitis A cases did not differ from 18 susceptible controls with respect to age, sex, or number of doses used. When compared with controls in multivariate analysis, case-patients were more likely to have injected methamphetamine (odds ratio (OR) = 5.5, 95% confidence interval (CI): 1.1, 27), to have used methamphetamine with another case-patient (OR = 6.2, 95% CI: 0.95, 41), and to have used brown methamphetamine (OR = 5.5, 95% CI: 0.51, 59). Receptive needle sharing was reported by 10 of the 20 case-patients who injected. Methamphetamine use with another case-patient was also associated with hepatitis A in an analysis restricted to noninjectors (OR = 17, 95% CI: 1.0, 630). During this outbreak, hepatitis A may have been transmitted from person to person among methamphetamine users through the fecal-oral and the percutaneous routes. Methamphetamine users should be vaccinated against hepatitis A and should be given immune globulin if they used methamphetamine with a case-patient in the last 2 weeks. Persons who intend to continue using methamphetamine should be advised about safer practices. (+info)
Overexpression of Grb2 in inflammatory lesions and preneoplastic foci and tumors induced by N-nitrosodimethylamine in Helicobacter hepaticus-infected and -noninfected A/J mice.
(30/837)
Growth factors bind to membrane receptor tyrosine kinases, resulting in autophosphorylation and subsequent binding to proteins with SH2 domains, including growth factor receptor-bound protein 2 (Grb2). Grb2 bridges receptors to tyrosine kinase substrates such as SHC and SOS, which in turn facilitate the activation of downstream signaling pathways, including Ras and mitogen-activated protein kinase (MAPK). Overexpression of Grb2 has been demonstrated in several types of neoplasia but has not been investigated in liver tumorigenesis. Here we investigated Grb2 expression in liver lesions in N-nitrosodimethylamine (NDMA)-treated Helicobacter hepaticus-infected and -noninfected A/J mice at 1 year of age. Previously, we reported (6) that infection promotes the development of these NDMA-initiated tumors. In controls, Grb2 immunostaining was absent from normal hepatic tissues, whereas the inflammatory lesions in infected livers were positive for cytoplasmic Grb2 in both hepatocytes and infiltrating leukocytes. All preneoplastic foci (7 of 7), 15 of 27 adenomas, and 3 of 7 carcinomas were positive for Grb2 by immunostaining in both infected and noninfected NDMA-initiated livers. Involvement of Grb2 was confirmed by immunoblotting of similarly infected mice at 9 to 18 months of age, showing a 2.5- to 3.3-fold increase in Grb2 protein in infected livers (p < 0.05 compared with uninfected controls) as well as in preneoplastic foci, adenomas, and carcinomas. These livers also showed a 2.5- to 2.8-fold increase in total Ras protein. The results suggest that upregulation of Grb2 is an early event in liver carcinogenesis, whether caused by the bacterial infection or by NDMA. Concomitant upregulation of Ras p21 would ensure transmission of amplified signal from growth factors via Grb2. (+info)
Detection of hepatitis A antibodies by ELISA using saliva as clinical samples.
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The possibility of detecting acute infection and immunity using body fluids that are easier to collect than blood, mainly in children, would facilitate the investigation and follow-up of outbreaks of hepatitis A (HAV). Our study was carried out to evaluate the detection of anti-HAV IgM, IgA and total antibodies in saliva using serum samples as reference. Forty three paired serum and saliva samples were analyzed. From this total, 24 samples were obtained from children and 1 from one adult during the course of acute hepatitis A; an additional 18 samples were obtained from health professionals from Adolfo Lutz Institute. The sensitivity to detect anti-HAV IgM was 100% (95%CI: 79.1 to 100.0%), employing saliva as clinical samples. In detecting anti-HAV IgA, the sensitivity was 80. 8% (95%CI: 60.0 to 92.7%) and for the total antibodies was 82.1% (95%CI: 62.4 to 93.2%). The specificity was 100% for each. The rate of agreement was high comparing the results of serum and saliva samples for detecting HAV antibodies. We conclude that saliva is an acceptable alternative specimen for diagnosing acute hepatitis A infection, and for screening individuals to receive hepatitis A vaccine or immunoglobulin. (+info)
Hepatitis A associated with other focal infections.
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BACKGROUND: Concomitant bacterial and viral infection is a well-known phenomenon, however only very rarely has a bacterial infection been reported during hepatitis A virus infection. OBJECTIVE: To evaluate retrospectively the clinical records of children hospitalized with HAV infection for a concomitant infection proved or presumed to be bacterial. METHOD: A retrospective study was conducted on all the children hospitalized with hepatitis A infection from 1988-96 in our center. The records were evaluated for a concomitant infection. RESULTS: Of 40 children hospitalized with HAV infection, 13 were found to have a concomitant infection: these included 6 with pneumonia, 4 with pyelonephritis and 1 case each of purulent otitis media, osteomyelitis and staphylococcal bacteremia. CONCLUSION: In areas where hepatitis A is endemic, a simultaneous infection with hepatitis A and other common bacterial infection during childhood may co-exist. A permissive role for HAV infection is suggested. (+info)