A novel deletion mutant of hepatitis B virus surface antigen.

HBsAg is the most important serological marker for acute or chronic hepatitis B. Nevertheless, there are reports of HBsAg-negative virus carriers, either with anti-HBc as the only marker for hepatitis B virus (HBV) infection or even positive for anti-HBs and anti-HBc. We report isolates from a patient, in which a deletion in the HBs-gene was associated with persisting viremia in the presence of anti-HBs.

Evaluation of a simple screening test for the quality of drinking water systems.

A simple and inexpensive assay for detection of H2S producing bacteria in drinking water was evaluated in Paraguay. Using an improved preparation procedure, results were basically temperature independent in the range of 22-37 degrees C and correlated well with the presence of total coliform bacteria (96%, 28 degrees C). The assay was not suitable for control of surface water and dug well water due to the frequent presence of non-faecal coliforms.

A seroepidemiological survey of antibodies to HTLV-I/HTLV-II in selected population groups in Paraguay.

Between March 1987 and November 1989 a cross-sectional serological survey was conducted on 884 residents of Paraguay to obtain data on the prevalence of antibodies to human T-cell leukemia virus type I/II (HTLV-I/II). Sera from 8/884 individuals (0.9%) were positive, confirmed by Western blotting and radioimmunoprecipitation (RIPA).

Mycotic keratitis in Paraguay.

Patients with corneal ulcer, residing mainly in rural areas of Paraguay, were controlled for mycotic eye infections. In 26 cases out of 45 (58%) presence of filamentous fungi was observed (Fusarium sp. (11), Aspergillus sp.

IgG antibody reactivity with Trypanosoma cruzi and Leishmania antigens in sera of patients with Chagas' disease and leishmaniasis.

Sera from 38 Paraguayans with positive skin tests to Leishmania braziliensis panamensis and 51 sera from Paraguayan patients in different stages of Chagas' disease were analyzed by Western blotting using antigen from Trypanosoma cruzi Y strain epimastigotes and from L. b. panamensis promastigotes.