Analysis of worm burden variation in human Schistosoma mansoni infections by determination of serum levels of circulating anodic antigen and circulating cathodic antigen.

Serum circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) concentrations, as a possible direct measure of worm burden, were compared with fecal egg counts in a heavily Schistosoma mansoni-infected population from Zaire to allow differentiation between worm loads and worm fecundity in relation to age and intensity of infection. Of the 517 subjects, 95% excreted eggs and 97% demonstrated circulating antigens. Fecal egg counts showed an age-related pattern characteristic for an area in which schistosomiasis is endemic with intense transmission levels. Regression analysis showed that antigen concentrations were strongly associated with egg counts. For CAA, but not for CCA, this relation was found to be nonlinear, which would be consistent with density-dependent fecundity or crowding. The trend was uniform for all age groups, which for this particular population indicated a genuine reduction of worm loads rather than reduced worm fecundity with age of the host.

Eight years of targeted mass treatment of Schistosoma mansoni infection in Maniema, Zaire.

Eight to ten years of follow-up the impact of targeted mass treatment, given to heavily infected people in Maniema's tin-mining district in Zaire, showed that the prevalence and intensity of infection were almost the same as before control. The high frequence of hepatomegaly, and to a lesser extent of splenomegaly, which were shown to be related to schistosome infection, however, have disappeared. For the evaluation of the impact of control, other parameters than egg counts only need further development.

[Initial resistance to streptomycin, isoniazid, thiacetazone, rifampicin and ethambutol in bacilliferous tuberculosis in Maniema, Zaire]. / Résistance initiale à la streptomycine, l'isoniazide, la thiacétazone, la rifampicine et l'éthambutol chez des tuberculeux bacillifères au Maniéma, Zaïre.

Initial resistance to streptomycin, isoniazid, thiacetazone, rifampicin and ethambutol was tested in 102 patients with bacilliferous tuberculosis in Kalima, a rural area in eastern Zaïre. The initial resistance for at least one of these tuberculostatics was 43%. The highest resistance recorded was for streptomycin (31%). No resistance to rifampicin or ethambutol was found. The practical interest of these findings is discussed.

Circulating anodic antigen levels in serum before and after chemotherapy with praziquantel in schistosomiasis mansoni.

The kinetics of serum levels of circulating anodic antigen (CAA) of Schistosoma mansoni were studied in patients with intestinal schistosomiasis before and after treatment with praziquantel. Day to day fluctuation in faecal egg excretion was compared with fluctuation in antigen level in 20 patients by serum and stool examination on 3 consecutive days before treatment. Antigen levels - calculated either as absorbance value of undiluted serum or as titre - showed less fluctuation than the number of eggs per gram of faeces determined by stool examinations based on single or duplicate 25 mg Kato smears. Compared with a placebo control group of 11 individuals, there was a significant reduction in CAA level in serum of 10 patients treated with praziquantel (40 mg/kg), 10 weeks after treatment. A similar decrease in serum CAA level was observed in a group of 46 patients treated with praziquantel, 6 weeks after treatment. In both groups, patients who remained seropositive after treatment still excreted eggs in their faeces. The kinetics of the antigen decrease were studied in more detail in 20 patients in hospital. Within 10 d after treatment with a double dose of 40 mg praziquantel per kg body weight, the antigen level fell to less than 10% of the original serum level, with a CAA half-life of approximately 2 d.

[[Potential and limitations of the long-term treatment of bacilliferous tuberculosis in Maniema (Zaire)]. / Potentiel et limites du traitement de longue durée de la tuberculose baccilifère au Maniéma (Zaïre).

Results after one year treatment of tuberculosis with a regimen associating streptomycin, isoniazid and thiacetazone in a rural region of eastern Zaïre are analyzed. A 46.9% cure rate is found. A high death rate (21.5%) and a relatively low number of "lost" patients (13.8%) are noted. The usefulness of the introduction of short term chemotherapy is discussed.

Quantitative determination of circulating antigens in human schistosomiasis mansoni using an indirect hemagglutination assay.

In serum and urine specimens collected from a group of Schistosoma mansoni infected individuals from Makundju, Zaire, the schistosome circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA) were quantitatively determined using an indirect hemagglutination reaction with sheep erythrocytes sensitized with mouse IgM monoclonal antibodies directed against these circulating antigens. Levels of CAA in serum (up to 5 ng/ml) and CCA in serum and urine (up to 50 ng/ml) were strongly correlated with egg excretion and with each other. No correlation was found between egg excretion and antibody levels against the circulating antigens. Antigen was detectable only in patients excreting greater than 500 eggs per gram of feces.