Immunofluorescence assay reactivity patterns of serum samples presenting indeterminate Western blot results for antibodies to HIV-1 and HTLV-I/II in Cordoba, Argentina.

Serum samples (n: 110) from blood donors and high risk individuals from Cordoba, Argentina with indeterminate HIV-1 and HTLV-I/II Wb profiles were studied for specific antibodies to HTLV-I/II and HIV-1 by indirect immunofluorescence assay (IFA) and for the presence or absence of HIV-1 and HTLV-I/II specific bands by Wb. This study was carried out in order to characterize their putative reactions with HIV-1 and HTLV-I/II proteins and to resolve the retrovirus infection status of these individuals. Results indicated that blood donors sera displaying indeterminate HIV-1 or HTLV-I/II Wb patterns were not immunoreactive to HTLV-I/II and HIV-1 on IFA. However, a high rate of indeterminate HIV-1 and HTLV-I/II Wb samples from high risk individuals had positive HTLV-I/II and HIV-1 IFA results respectively. Our study supports the growing evidence that HTLV-HIV indeterminate seroreactivity in low risk population is due to a cross reaction against nonviral antigens, and in high risk populations the indeterminate samples show serological cross-recognition between HIV-1 proteins and HTLV-I/II proteins on Wb. These results point out the necessity to investigate the HTLV-I/II reactivity in indeterminate HIV-1 samples and vice versa in order to confirm the diagnosis. Finally, this study shows the potential usefulness of IFA in elucidating the status of HIV-1 and HTLV-I/II infection of individuals with indeterminate Wb profiles, thus enabling resolution of retrovirus infection status.

[HTLV-I/II seroprevalence and risk factors associated with infection in a blood donor population in Córdoba, Argentina]. / Seroprevalencia de HTLV-I/II y factores de riesgo asociados a la infección en la población de donantes de sangre de Córdoba, Argentina.

In this study we have determined the seroprevalence of infections by HTLV-I/II in the blood donor population from the city of Córdoba. A total of 5476 blood donor sera were screened for HTLV-I/II antibodies by particle agglutination assay (PA) (SERODIA HTLV-I, Fujirebio INC, Tokyo, Japan). The reactive sera samples were confirmed by an "in house" indirect immunofluorescence assay (IFA). 14 out of 5476 blood donors studied were PA reactive and were confirmed positive by IFA, showing a prevalence of 0.26% (95% confidence interval: 0.126%-0.394%). All the positive samples, except one, met the criteria for HTLV-I. Although one HTLV-I infected donor was an intravenous drug abuser and two donors were born in highly endemic areas for HTLV-I, no specific risk factors were identified among the others. The demonstration that HTLV-I circulates in blood donor population of Córdoba, points out that the systematic screening of blood for HTLV-I/II antibodies must be implemented in the blood banks, in an attempt to prevent the spread of infections with this oncogenic virus in Argentina.

[Distribution of hepatitis B antigen in Cordoba, Argentina]. / Distribución del antígeno de la hepatitis B en Córdoba, Argentina

This article presents the results obtained in the search for the hepatitis B antigen by the counter-immunoelectrophoresis technique in sera of more than 50.000 persons from Córdoba, Argentina. Groups of voluntary blood donors, general population, 20 years old army recruits, patients, with acute hepatitis and patients admitted to a hospital due to other diseases were included in this study. In the apparenly healthy population the positivity of the test ranged between 0.33 to 0.53 percent; the highest rate was found among the recruits. In the group of patients with acute hepatitis, 38.53% of the sera were positive. No statistically significant differences were observed in the monthly distribution of the hepatitis B antigen during the period of study. These results are compared with those found by other workers in different countries. This study shows the importance of the early detection of the hepatitis B antigen in blood donors, to reduce the incidence of hepatitis transmitted by transfusions. The importance of establishing centers for the standardization and control of reagents, as well as for the training of laboratory personnel is emphasized.

Serum pregnancy-associated alpha 2-glycoprotein levels in the evolution of hepatitis B virus infection.

Serum pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) levels were evaluated in a follow-up study of patients with hepatitis B virus (HBV) infection and compared with biochemical and virological parameters. In a study of 25 patients with acute hepatitis, an association was found between high alpha 2-PAG values, ALT levels, and HBsAg in 20 patients (80%) (P less than 0.05), 18 recovered completely, and 2 had a protracted course. In five patients serum alpha 2-PAG levels were similar to those in the control group. On the other hand, eight (100%) chronic persistent HBV patients showed high levels of alpha 2-PAG (P less than 0.05) during the study period, and these levels correlated well with inflammatory activity and failure of HBsAg elimination. There were no significant differences in alpha 2-PAG values between asymptomatic HBsAg carriers and controls. Serial analysis of alpha 2-PAG, in correlation with viral markers, biochemical parameters, and histological data, would contribute to the ability to predict the final outcome of HBV infection.

Serologic study by competitive enzyme-linked immunosorbent assay of pregnancy-associated alpha 2-glycoprotein in hepatitis B virus infection.

Serum levels of pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) in patients with hepatitis B virus (HBV) infection were compared with those of healthy male subjects used as controls by a competitive enzyme-linked immunosorbent assay (ELISA). Assay parameters were optimized, and minimal detectable concentration was 100 ng/ml. The alpha 2-PAG levels in 22/26 acute HBV patients showed a very significant statistical difference when compared with controls (x2 = 19.93, p less than 0.0005). On the other hand, 8/8 chronic persistent HBV patients showed high levels with a range between 51 to 200 ug/ml (x2 = 18.16, p less than 0.0005). There was no significant difference between asymptomatic HBsAg carriers and controls. Although alpha 2-PAG apparently exhibits immunosuppressive properties similar to other factors present in HBV infection, follow-up studies are needed to elucidate its role in the natural evolution of this disease.

Hepatitis A virus in stool during clinical relapse.

Among 256 patients with acute hepatitis A, 17 (6.6%) had a relapse of the disease between 30 and 90 days after the primary episode. We studied 7 of these patients. Serologic testing showed mean alanine aminotransferase levels of 1668 IU/L during the acute stage, 107 IU/L during the early convalescence, and 1027 IU/L during the relapse. Tests for IgM antibody against hepatitis A virus were positive in the 7 patients at the onset of disease, with decreasing levels in 3 of the 4 patients tested during the evolution of the illness. Stools collected during the relapse phase showed hepatitis A virus by immune electron microscopy, radioimmunoassay, and molecular hybridization using a 32P-labeled cDNA-hepatitis A virus probe. Stools collected from 4 of these patients 6 to 12 months after the onset of disease were negative for the virus. The finding of hepatitis A virus in the stool of these patients during the relapse phase strongly implicates hepatitis A virus as the causative agent of the clinical relapse.

Hepatitis B and C virus sexual transmission among homosexual men.

OBJECTIVE: We estimated hepatitis B virus (HBV) and hepatitis C virus (HCV) sexual transmission among homosexual men. METHODS: Two hundred twenty-eight homosexually active men attending two clinical centers and presenting no risk factors except for sexual exposure were interviewed, and a blood sample was drawn. HBV marker test was performed using enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay, and HCV was tested using ELISA-2 and recombinant immunoblot assay-2. RESULTS: HBV and HCV infection prevalence rates were 34.4% and 12.7%, respectively. Using logistic regression analysis including sexual exposure and controlling for confounders, we found that anal receptive intercourse (odds ratio [OR] = 4.01; 95% confidence interval [CI] = 1.34-11.94), duration of homosexuality (OR = 3.43; 95% CI = 1.29-9.12), insertive anilingus (OR = 2.02; 95% CI = 1.06-3.87), and sexually transmitted diseases (OR = 1.87; 95% CI = 1.00-3.47) were independently associated with the risk of HBV sexual transmission. We did not find any association between sexual behavior and HCV transmission. CONCLUSIONS: Sexual behavior is a plausible explanatory factor of HBV sexual transmission among homosexual men. Further evidence is needed to elucidate the occurrence and the efficiency of HCV sexual transmission in the absence of other risk factors.

Aislamiento de virus rábico de murciélagos insectívoros en Córdoba, Argentina / Isolation of rabies virus from insectivorous bats in Cordoba, Argentina

In 1963, the Córdoba Public Health Service initiated an Antirrabies Program which was directed by Dr. José M. Vanella. By that time Córdoba, a city of about 900,000 inhabitants, had 100 to 400 cases of laboratory confirmed dog rabies per year. Since 1967 no cases of urban rabies have been detected

A permanent program of dog vaccination and rabies surveillance is maintained by the local Health Service. A new reason for increasing efforts in control measures has come about after the finding of bat rabies in Córdoba

Three out of 81 Tadarida brasiliensis brasiliensis were found infected with rabies virus. This fact was demonstrated by Seller's method, immunofluorescence and specific neutralization of the recovered agents. There is no available information on the ecology of these bats in the Province, and we think it will be of great interest to find out whether or not they are migratory bats(AU)

Aislamiento de virus rábico de murciélagos insectívoros en Córdoba, Argentina / Isolation of rabies virus from insectivorous bats in Cordoba, Argentina

In 1963, the Córdoba Public Health Service initiated an Antirrabies Program which was directed by Dr. José M. Vanella. By that time Córdoba, a city of about 900,000 inhabitants, had 100 to 400 cases of laboratory confirmed dog rabies per year. Since 1967 no cases of urban rabies have been detected

A permanent program of dog vaccination and rabies surveillance is maintained by the local Health Service. A new reason for increasing efforts in control measures has come about after the finding of bat rabies in Córdoba

Three out of 81 Tadarida brasiliensis brasiliensis were found infected with rabies virus. This fact was demonstrated by Seller's method, immunofluorescence and specific neutralization of the recovered agents. There is no available information on the ecology of these bats in the Province, and we think it will be of great interest to find out whether or not they are migratory bats(AU)

Seroprevalencia de HTLV-I/II y factores de riesgo asociados a la infección en la población de donantes de sangre de Córdoba, Argentina / HTLV-I/II seroprevalence and risk factors associated with infection in a blood donor population in Córdoba, Argentina

In this study we have determined the seroprevalence of infections by HTLV-I/II in the blood donor population from the city of Córdoba. A total of 5476 blood donor sera were screened for HTLV-I/II antibodies by particle agglutination assay (PA) (SERODIA HTLV-I, Fujirebio INC, Tokyo, Japan). The reactive sera samples were confirmed by an "in house" indirect immunofluorescence assay (IFA). 14 out of 5476 blood donors studied were PA reactive and were confirmed positive by IFA, showing a prevalence of 0.26 (95 confidence interval: 0.126-0.394). All the positive samples, except one, met the criteria for HTLV-I. Although one HTLV-I infected donor was an intravenous drug abuser and two donors were born in highly endemic areas for HTLV-I, no specific risk factors were identified among the others. The demonstration that HTLV-I circulates in blood donor population of Córdoba, points out that the systematic screening of blood for HTLV-I/II antibodies must be implemented in the blood banks, in an attempt to prevent the spread of infections with this oncogenic virus in Argentina.