Non-A, non-B hepatitis among participants in a plasmapheresis stimulation program

Transfusion-Associated HIV Infection in Mexico Related to Paid Blood Donors; HIV Epidemic

The objective of the study was to describe the clinical, epidemiological profile and conditional incubation period in a group of transfusion-associated HIV-infected (TAHI) patients seen in five national tertiary care centres in Mexico from 1983 to April 1998. Date of transfusions, AIDS diagnoses, opportunistic infections and malignancies were collected. The incubation period was estimated through a non-parametric conditional analysis.

One hundred and fifty-seven TAHI cases were analysed. The frequency of TAHI by year of transfusion was: 0.6% in 1980 and 1981, 4.5% in 1984, 22.4% in 1985, 54.5% in 1986, 10.3% in 1987, 0.6% in 1988, 1.9% in 1989 and 1990, 1.3% in 1993 and 0.6% in 1994 and 1996. The median incubation period was 4.3 years.

A well-defined epidemic period of HIV-infection among blood-recipients was identified that coincided with the HIV-epidemic among paid donors. TAHI patients in Mexico developed AIDS in a shorter time than that described for other populations.

The emerging nosocomial pathogens Cryptosporidium, Escherichia coli O157:H7, Helicobacter pylori, and hepatitis C: epidemiology, environmental survival, efficacy of disinfection, and control measures

New and emerging infectious diseases pose a threat to public health and may be responsible for nosocomial outbreaks. Cryptosporidium parvum and Escherichia coli are gastrointestinal pathogens that have caused nosocomial infections via person-to-person transmission, environmental contamination, or contaminated water or food. Helicobacter pylori has been transmitted via inadequately disinfected endoscopes. Finally, hepatitis C may be acquired by healthcare personnel by percutaneous or mucous membrane exposure to blood or between patients by use of contaminated blood products or via environmental contamination. Rigorous adherence to Standard Precautions, Contact Precautions for patients with infectious diarrhea, disinfection of environmental surfaces, and appropriate disinfection of endoscopes are adequate to prevent nosocomial acquisition of these pathogens.

Hepatitis C virus infection in the United States

Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States, and most infected persons are younger than 50 years old. The relative importance of the two most common exposures associated with transmission of HCV, blood transfusion and intravenous drug use (IVDU), has changed over time. Blood transfusion, which accounted for a substantial proportion of HCV infections acquired >10 years ago, rarely accounts for recently acquired infections. In contrast, IVDU has consistently accounted for a substantial proportion of HCV infections and currently accounts for 60% of HCV transmission while sexual exposures account for up to 20%. Other known exposures (occupational, hemodialysis, household, perinatal) together account for about 10% of infections. In the remaining 10%, no recognized source of infection can be identified, although most persons in this category are associated with low socioeconomic level. Case-control studies have found no association with military service or exposures resulting from medical, surgical or dental procedures, tattooing, acupuncture, ear piercing or foreign travel. Reducing the burden of HCV infection and disease in the United States requires implementation of primary prevention activities that reduce or eliminate HCV transmission and secondary prevention activities that reduce liver and other chronic diseases in HCV-infected persons by identifying them and providing appropriate medical management and antiviral therapy. Surveillance and evaluation activities also are important to determine the effectiveness of these programs in reducing the incidence of disease, identifying persons infected with HCV, and promoting healthy lifestyles and behaviors.

Prevalence of markers of hepatitis viruses in out-patient alcoholics

The prevalence of HCV, HBV and HAV markers was investigated in unselected patients attending an outpatient alcoholic clinic. Anti-HCV were detected in 35 (24%) of 144 patients studied, and at least one marker of HBV infection was present in 72 (50%). These results are significantly higher than in a matched control population. The presence of anti-HCV was related to previous blood transfusions and familial history of alcoholism. We conclude that alcoholics should be considered a high risk group for both HCV and HBV infection.

Hepatitis C: a sleeping giant?

In the United States, non-A, non-B hepatitis accounts for 20-40% of acute viral hepatitis. Although it has traditionally been considered a transfusion-associated disease, non-A, non-B hepatitis is more likely to occur outside the transfusion setting. Surveillance data from the Centers for Disease Control show that in 1988 6% of patients with non-A, non-B hepatitis reported a history of blood transfusion, 46% parenteral drug use, 10% household or sexual exposure to a contact who had had hepatitis or exposure to multiple sex partners, 2% medical or dental employment involving frequent blood contact, less than 1% hemodialysis, and 40% no known source. Antibody to hepatitis C virus (anti-HCV) is found in the majority of patients with non-A, non-B hepatitis independent of the source of infection; however, antibody may not appear for 6 to 9 months after exposure or onset of illness. Limited serologic studies of the prevalence of anti-HCV in various population groups have found high anti-HCV rates (50-80%) in parenteral drug users and hemophiliacs, intermediate rates among the sexually active (5-15%), and low rates among health care workers (1%). In persons with acute or chronic hepatitis C, the presence of anti-HCV appears to indicate infectivity. Persons with no history of hepatitis who are anti-HCV positive may or may not be infectious. More sensitive and specific markers for the detection of hepatitis C virus will be needed to resolve this question.

An outbreak of non-A, non-B hepatitis associated with the infusion of a commercial factor IX complex during cardiovascular surgery

An outbreak of non-A, non-B hepatitis was recognized among cardiovascular surgical patients from one hospital in June 1985. Illness was found to be significantly associated with a commercial brand of factor IX complex given to patients because of intraoperative bleeding. A change in the commercial brand of factor IX stocked by the hospital pharmacy had occurred in October 1984 and coincided with the onset of the outbreak. A retrospective study of cardiovascular surgery patients identified 23 cases and 7 probable cases of non-A, non-B hepatitis among patients who had received infusions of brands A and B factor IX complex. Three cases were in brand A recipients and 27 were in brand B recipients. Respective brand-specific attack rates were 5 and 42% (relative risk = 7.7; p less than 2 x 10(-5); chi 2 test). Nineteen of 30 case patients (63%) were jaundiced, including 2 brand A recipients and 17 brand B recipients. Median peak serum aminotransferase was 690.5 IU (range 27-2,824). The incubation period for cases in brand B recipients was a median of 7 weeks (range 2-17 weeks). Prevention of non-A, non-B hepatitis in this population requires adhering to strict indications for the use of clotting factor preparations and avoiding these products when at all possible. Heat treatment of clotting factor products may reduce the risk of viral disease transmission, but certain methods may not inactivate the causative agents of non-A, non-B hepatitis.

Mother to infant transmission of hepatitis C virus infection

Eight women with chronic hepatitis C virus (HCV) infection during pregnancy gave birth to 11 children. Five of these children had elevated ALT, but only two had increased levels in more than one sample. All children tested before 6 months of age were positive for anti-HCV at most up to 7 months of age and then became negative. One child with a maximum ALT level of 8.4 mukat/l however, regained anti-HCV positivity at 12 months of age, and a liver biopsy at 21 months of age showed resolving hepatitis. Passively acquired HCV antibodies are obviously found in newborns of anti-HCV-positive mothers with chronic hepatitis. In 1 of 11 children, active anti-HCV production and concomitant liver disease suggested mother to infant transmission of hepatitis C virus infection.

The agents of non-A, non-B viral hepatitis

Recent studies have provided physicochemical and electron microscopic evidence for the existence of two distinct agents of posttransfusion non-A, non-B (NANB) hepatitis. One of these agents is chloroform-resistant and is not associated with the formation of unique ultrastructural structures in infected liver. The other agent is CHCl3-sensitive, induces the formation of characteristic hepatocyte cytoplasmic tubules, and interferes with concurrent HAV or HBV infection in experimentally inoculated chimpanzees. The tubuleforming agent (TFA) has also been shown to pass through an 80 nm capillary pore membrane filter, suggesting that it is a small enveloped (or lipid-containing) virus. The TFA can also be recovered from low titer (less than or equal to 10(5) infectious doses/ml) chronic-phase chimpanzee plasma by use of a multi-step purification procedure that assumes the agent is a small enveloped RNA virus with an approximate buoyant density of 1.24 g/cm3 and a sedimentation coefficient of 200-280 S. The apparent lack of nucleic acid homology between the NANB-TFA and HBV further suggests that the NANB-TFA is either Togavirus-like or belongs to another or as yet undefined class of RNA or DNA virus.

Non-A, non-B viral hepatitis

Non-A, non-B hepatitis is a newly recognized disease entity. Although initially described as a transfusion related viral infection, the disease can occur in sporadic, endemic, and epidemic settings. There are no confirmed, reproducible serologic tests for associated antigens or antibodies, but electron microscopy has revealed virus-like particles of different sizes. Nonspecific laboratory tests of hepatic dysfunction, especially alanine aminotransferase, are currently utilized to diagnose non-A, non-B hepatitis in patients and may be used to implicate blood donor carriers of this virus. The existence of an infectious non-A, non-B hepatitis agent and proof of a chronic carrier state in humans have been documented by transmission studies in chimpanzees. Cross challenge studies in chimpanzees, as well as some epidemiologic data, suggest that more than one agent causes non-A, non-B hepatitis.

Disappearance of hepatitis B surface antigen during an unusual case of fulminant hepatitis B

A 30-year-old surgical resident was admitted to the hospital with symptoms of acute hepatitis; two days later he became comatose. Hepatitis B surface antigen had been detected in his serum two days prior to admission, but it was not detected at any time thereafter. Hepatitis B e antigen, antibody to hepatitis B core antigen, and antibody to hepatitis B surface antigen were detected using sensitive radioimmunoassays at admission. Titers of antibody to hepatitis B core antigen increased over the next five weeks. Clearance of hepatitis B e antigen and subsequent appearance of antibody to hepatitis B e antigen accompanied clinical improvement and recovery. This unusual case documents that hepatitis B surface antigen can become undetectable during the course of fulminant hepatitis B and indicates the importance of tests for other serologic markers of hepatitis B virus in the evaluation of hepatitis B surface antigen-negative fulminant hepatitis.

Non-A/non-B hepatitis in experimentally infected chimpanzees: cross-challenge and electron microscopic studies

Inoculation of eight chimpanzees with factor VIII, factor IX, or "H" strain plasma resulted in enzymatic and histopathologic evidence of non-A/non-B hepatitis in all eight animals. Challenge of two chimpanzees convalescent from factor VIII-induced disease with either factor IX or "H" strain plasma resulted in non-A/non-B hepatitis only in the animal inoculated with factor IX materials. Reciprocal cross-challenge of a chimpanzee convalescent from factor IX-induced disease with factor VIII also produced unequivocal enzymatic and histopathologic evidence of non-A/non-B hepatitis. Cross-challenge of a chimpanzee convalescent from "H" strain-induced non-A/non-B hepatitis with factor VII did not cause a second bout of non-A/non-B hepatitis. These findings suggest the factor VIII materials and "H" strain plasma used in these studies share a common etiologic agent (or agents), but that factor VIII and factor IX may contain two distinct agents. Electron microscopic (EM) examination of thin-sectioned, acute-phase liver biopsies from all but one of the chimpanzees receiving the primary inocula revealed the presence of abnormal hepatocyte cytoplasmic structures previously shown to be associated with non-A/non-B hepatitis. Crystalline structure containing 25 to 30 nm particles were visualized by EM in the cytoplasm of endothelial or Kupffer cells in acute-phase liver biopsies obtained from three chimpanzees inoculated with either factor VIII materials or "H" strain plasma.