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.

Seroprevalence of human parvovirus B19 infection in Sao Tomé and Principe, Malawi and Mascarene Islands.

The prevalence of antibodies to human parvovirus B19 (anti-B19 IgG) in sera (n = 577) from Sao Tomé and Principe, Malawi and Mascarene Islands (Mauritius and Rodriguez Islands) was determined by antibody capture ELISA. The B19 prevalence was 51.5% on Sao Tomé and Principe, 58.

Detection of Chlamydia trachomatis by isolation in cell culture and enzyme amplified immunoassay.

188 (139 female; 49 male) genital swabs from patients with urogenital complaints (greater than 6 weeks), 69 (33 female; 36 male) conjunctival swabs from patients with chronic conjunctivitis and 14 swabs from newborns with acute conjunctivitis were tested for the presence of Chlamydia trachomatis (Ct) by inoculation in cell culture and visualisation by indirect immunofluorescence (IFT) with a monoclonal antibody and enzyme immunoassay (ELISA). Of the 271 specimens 20 (7.4%) were Ct positive by cell culture (IFT) and 18 (6.

Reactogenicity and immunogenicity of the newly developed purified chick embryo cell (PCEC)-rabies vaccine in man.

Purified Chick Embryo Cell (PCEC) rabies vaccine was given to 88 healthy adults according to six different vaccination schedules. Local side effects were reported on reactivity forms after 16.4% of PCECV injections, general symptoms were recorded after 15.

Different immune responses after intradermal and intramuscular administration of vaccine against tick-borne encephalitis virus.

A single multisite intradermal (ID) administration of the same dose used for regular intramuscular (IM) immunisation with vaccine against tick-borne encephalitis virus (TBEV) resulted in seroconversion of all vaccinees within three weeks: with the regular IM schedule, two vaccinations were necessary for all vaccinees to seroconvert. After the first ID vaccination, antibodies of the IgM class against TBEV (anti-TBEV-IgM) were observed in all vaccinees; after the first IM vaccination, only three out of nine vaccinees showed an IgM response. The geometric mean titer (GMT) of anti-TBEV-IgM in seropositives was 5-20-fold higher in the ID group and similar to that after natural infection.

[Increase in the prevalence of antibodies against LAV/HTLV III in drug addicts in West Germany].

Sera obtained from 927 drug addicts in 1983 to 1985 were tested for antibodies against LAV/HTLV-III. There was a steadily rising proportion of positive results: 10.1% in 1983, 17.

Epidemiological studies on the prevalence of hepatitis Delta virus infections in the Federal Republic of Germany.

This study evaluated the prevalence of hepatitis Delta virus (HDV) infections in various groups of HBsAg carriers including drug addicts and patients with hemophilia in the Federal Republic of Germany. HDV was found only occasionally (less than 1%) in individuals found HBsAg positive during an examination as potential blood donors or in hemodialysis patients, but in 3% in patients with chronic hepatitis and up to 50% in drug addicts and hemophilia patients. These findings are in agreement with data reported from other European countries.

Markers of hepatitis viruses A and B: direct comparison between whole serum and blood spotted on filter-paper.

The use of blood spotted on filter-paper is a cheap and convenient method for collecting, storing and transporting samples for analysis of markers of hepatitis virus B. Vaccine against viral hepatitis B is now available but is expensive, and, in order to make the best use of it, large-scale screening programmes need to be carried out in endemic areas prior to immunization campaigns. The sensitivity of the filter-paper method was compared with that of the analysis of whole serum, and the epidemiological data produced by the two methods were analysed.

Laboratory markers of immunity to varicella-zoster virus.

Clinical and subclinical reinfection with varicella-zoster virus (VZV) in healthy persons may occur despite detectable neutralizing antibodies in serum. Subclinical reinfection is not uncommon, but clinical reinfection is rare. Therefore, detectable anti-VZV antibody correlates with a subclinical course after reinfection rather than with immunity to reinfection.

Clinical evaluation of a recombinant hepatitis B vaccine.

Recombinant hepatitis B vaccine prepared from antigen expressed in yeast was given to 30 healthy young volunteers. Seroconversion rates and anti-HBs levels were compared with those in a control group matched for age and sex who had received plasma-derived hepatitis B vaccine. 4 weeks after the third immunisation results were similar in the two groups.

[Antibodies against human T-cell leukemia virus type III in acquired immunodeficiency syndrome and persistent lymphadenopathy].

HTLV III and LAV, retroviruses which have recently been described in the United States and France and which seem to be different isolates of the same virus, are closely associated with the acquired immune deficiency syndrome (AIDS) and the lymphadenopathy syndrome (LAS). Sera from male homosexuals from the Federal Republic of Germany with AIDS or LAS were examined for antibodies to HTLV III (anti-HTLV III) by means of the enzyme linked immunoadsorbent assay (ELISA) and by an indirect immunofluorescence assay. 53% of the patients were anti-HTLV III positive as were 20% of symptomless homosexual men.

[Hepatitis B and the delta agent].

The delta agent seems to be a defective RNA virus which is dependent on a helper function provided by hepatitis B-virus. Delta agent infection occurs by parenteral transmission either together with hepatitis B-virus, or superimposed on chronic HBV infection. In the first case biphasic hepatitis may result, whereas in the second case mostly an acute delta agent infection develops, which is often followed by chronic delta hepatitis.

Evaluation of a reduced dose of hepatitis B vaccine administered intradermally.

Intradermal inoculation of hepatitis B vaccine (HBsAg subtype adw) caused no side effects, but the vaccine was less immunogenic than following intramuscular administration. Intradermal inoculation does not, therefore, offer a major advantage to the generally used intramuscular immunization. A single multisite intradermal administration of a reduced dose of vaccine did not result in a more rapid seroconversion compared to intramuscular inoculation.