Examination of faecal material by Kato Katz (KK) technique is a widely used approach for the diagnosis of intestinal schistosomiasis, particularly in epidemiological surveys. However, this technique lacks diagnostic sensitivity in individuals with low infection intensity or in low endemic areas. In the total population (TP) of 1265 individuals prevalence and infection intensity were established by examining two KK slides. A representative subset of 305 individuals, denominated experimental group (EG), was defined to assess the comparative advantage of an increased sampling effort using the KK technique. In addition stools of the participants of the EG were examined by the formol ether centrifugation technique. The proportion of all positive stool examinations detected by both methods among the experimental group served as reference value for prevalence (diagnostic 'gold' standard). Prevalence of schistosomiasis among TP based on two KK slides was 12.5%. Prevalence among the EG varied from 13.8%, based on one KK slide, over 27.2 based on 10 KK slides of three stool samples to 35.4% as value for the diagnostic 'gold' standard. The comparison of values for prevalence, stratified by age, revealed significant elevated numbers for all age groups, and interestingly, an extension of the highest prevalence levels until an age of 50 years. The overall infection intensity in eggs per gram (epg), calculated as geometric mean, was 83 epg for the TP based on one KK slide, 78 epg for the GE based on one KK slide and 28 epg based on 10 KK slides of three stool samples. In summary our data demonstrate that control programmes based on the examination of a single KK slide, as it is the case in Brazil, tend to underestimate significantly the prevalence and overestimate infection intensity. This applies especially for low endemic areas, where the efficacy and cost-effectiveness of such programmes become questionable. Our data also indicate that the possible solution of this problem lies in targeted mass treatment including age groups with the highest proportions of those infected. This will give high sensitivity together with sustainability and suitability under field conditions.

A field trial was carried out in the eastern part of the State of Minas Gerais (Brazil) of a vaccine containing killed promastigotes of five stocks of Leishmania. Tests with Montenegro antigen showed that a high proportion of the vaccinated persons became positive within three months, but circulating antibodies were not detected. A proportion of those vaccinated continued to give positive Montenegro reactions for up to three years. Lymphocyte sensitivity tests carried out, on a small sample, three years after vaccination were positive and gave no evidence of immunological depression. No cases of cutaneous or mucocutaneous leishmaniasis occurred in the trial area during the three years of observations.

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Two controlled, double blind field trials of a non-living promastigote vaccine against New World Cutaneous Leishmaniasis (NWCL) were conducted in 1981 and 1983 in Brazil. Brazilian Army conscripts were randomly assigned to the vaccine or placebo groups and tested during their training in the Amazon jungle, a high risk area for NWCL. The results obtained showed: no significant differences between the vaccine and the placebo groups with respect to a number of characteristics (age, race, previous contact with the jungle, etc.); no significant differences between the participants who got and who did not get NWCL during the trial, with respect to length of exposure, contact with the jungle, etc. and a reduction of 67.3 and 85.7% in the annual incidence rate of NWCL, in 1981 and 1983 respectively (although the difference between incidence rates of the disease in vaccinated and control groups in the 1983 trial was not statistically significant), among those vaccinated who had converted to a positive leishmanin skin test as compared with the placebo groups.