C.C. Cuba

A histological classification of mucocutaneous leishmaniasis in Brazil and its clinical evaluation.

Biopsies of skin and mucosal lesions were made on 60 well documented Brazilian patients with untreated cutaneous or mucocutaneous leishmaniasis, whose response to treatment was subsequently evaluated in 38 cases. The biopsies were examined with a view to classification after correlation with clinical and immunological findings. Although there was no simple or unified spectrum, five histological groups were defined and found to have some clinico-prognostic significance. In two groups the cases were all cutaneous with a relatively good prognosis. In another two groups they were evolving as mucocutaneous with a poor prognosis. The fifth group showed mixed characteristics with a tendency to relapse. There was no strong correlation with serum antibodies or Montenegro skin test, which were usually positive, or with parasite load, which was always low. The tissue response was distinguished from that in oriental sore by the degree of connective tissue involvement in all groups. It was the primary response in two groups, and subsidiary to a mono-nuclear response in the others. It suggested damage due to extra-cellular parasites or immune complexes. It did not correlate with the distinction between cutaneous and mucocutaneous disease. The single, most favourable, prognostic feature in either the cellular or connective tissue component was necrosis with a reactive response.

Long-term follow-up of patients with Leishmania (Viannia) braziliensis infection and treated with Glucantime®

Seventy-nine patients with cutaneous (62) or mucosal (17) infection with Leishmania (Viannia) braziliensis in Três Braços, Bahia, Brazil, were followed for at least 4 years after initiating treatment with antimony. Cutaneous relapses occurred in 6/62 (10%), mucosal relapse after cutaneous infection in 2/62 (3%), and mucosal relapse after mucosal disease in 2/17 (17%). It is concluded that relapse (cutaneous and mucosal) is rare after adequate antimony therapy and that no definite prediction of relapse (clinical, serological or by skin reaction) is possible.

A focus of mucocutaneous leishmaniasis in Três Braços, Bahia, Brazil: characterization and identification of Leishmania stocks isolated from man and dogs

The characterization and identification to species and subspecies of 20 stocks of Leishmania isolated from the region of Três Braços, Bahia, Brazil, are described: 17 stocks were from patients and three from dogs. The following techniques were used (i) biological (growth in culture, hamster tissues and phlebotomine gut), (ii) biochemical (isoenzyme and kinetoplast DNA analysis) and (iii) immunological (using monoclonal antibodies). All except two stocks belong to the L. braziliensis complex. One of these two corresponded to L. mexicana amazonensis but the other, while clearly in the mexicana complex, showed slight differences from the L. mexicana amazonensis reference strain on isoenzyme analysis. Two stocks from different lesions in the same patient and with different growth characteristics in hamster tissues were both identified as L. braziliensis braziliensis. All the fully characterized stocks of the L. braziliensis complex were identified as L. braziliensis braziliensis. L. braziliensis guyanensis was not identified. Dog and human stocks of L. braziliensis braziliensis were indistinguishable. From these findings and other evidence, L. braziliensis braziliensis seems to be the predominant species transmitted in Três Braços.

Nifurtimox in the treatment of South American leishmaniasis

A trial of Nifurtimox (Lampit) in 26 patients with mucocutaneous leishmaniasis is reported. 13 patients with cutaneous lesions and 13 patients with mucosal disease were treated with a daily oral divided dose of 10 mg/kg body-weight for 30 days. 46% of the cutaneous cases and only 15% of the mucosal cases apparently responded to this regimen during at least one year of follow up. The difficulties of assessing cure in this disease are briefly discussed. We consider that Nifurtimox remains an investigational drug. While possibly exhibiting some anti-leishmanial activity it cannot be recommended for routine use in either form of the disease.

Phylogenetic taxonomy of Leishmania (Viannia) braziliensis based on isoenzymatic study of 137 isolates.

Biochemical characterization of 137 Leishmania braziliensis isolates from South and Central America, and from selected endemic foci in Bolivia, Brazil and Colombia, performed by isoenzymatic electrophoresis using 10 enzymatic systems, showed a high enzymatic polymorphism (44 zymodemes obtained) based on the variation of a small number of enzymes. Cladistic analysis showed close links between the zymodemes within the L. braziliensis s.s. cluster. The position of 2 Colombian zymodemes obtained (MON*204 and MON*205) justify the inclusion of L. peruviana within the L. braziliensis cluster.

Further trials of nifurtimox in mucocutaneous leishmaniasis

At a dosage level of 8 to 10 mg/kg body-weight daily for 120 days nifurtimox was associated with clinical healing of cutaneous leishmaniasis in five of eight patients. At a dosage level of 20 mg/kg body-weight daily for 10 days in six of 10 patients the skin ulcer healed. Results and the reasons why both schemes are impracticable are briefly discussed.

Dipetalogaster maximus (Hemiptera, Triatominae) for xenodiagnosis of patients with serologically detectable Trypanosoma cruzi infection.

In patients serologically positive for Trypanosoma cruzi infection the three bug species/instar combinations used in xenodiagnosis showed third-instar Dipetalogaster maximus to be more efficient in detecting circulating trypanosomes than the first instar of the same species which, in turn, is more sensitive than third-instar Triatoma infestans. The sensitivity of the pool technique of faecal examination compared with individual dissection was investigated. Four pool examinations (the product of 20 bugs) were equivalent to 10 individual bug dissections. Because of the ease of providing large numbers of bugs for mass xenodiagnosis, first-instar D. maximus has replaced third-instar T. infestans in our routine work. The value of third-instar D. maximus as a xenodiagnostic agent needs further investigation.

Immunological selection for Leishmania (Viannia) braziliensis antigens

Comparative ELISA and selective immunoblotting procedures were used in attempts to identify differential serological indicators of infection with the Leishmania (Viannia) braziliensis complex, infection with the L. braziliensis species, and therapeutic cure of localized or mucocutaneous leishmaniasis (LCL or MCL). Although mean ELISA absorbance values were significantly higher for MCL sera than for LCL sera, absorbance could not be used as a reliable indicator of the clinical form of disease. Immunoblotting profiles were similar with sera from MCL and LCL. Pre-adsorption with heterologous trypanosomatid antigens indicated that recognition of antigens of about 56, 60, 66, 72, 88 and 110 kDa might be specific to the subgenus Viannia. In two-colour, sequential, dual ELISA-based immunoblotting, no antigens recognized only by sera from MCL patients were detected. After glucantime therapy, immunoblotting profiles with LCL sera were reduced both in intensity and in the range of antigens detected; a 104-kDa antigen was newly detected with post-treatment LCL sera. Overall, the results show the value of differential immunological detection strategies and support the close relationship between species of the subgenus Viannia but fail to indicate a prognostic antigen for MCL.

Immunological selection forLeishmania(Viannia)braziliensisantigens

Comparative ELISA and selective immunoblotting procedures were used in attempts to identify differential serological indicators of infection with the Leishmania (Viannia) braziliensis complex, infection with the L. braziliensis species, and therapeutic cure of localized or mucocutaneous leishmaniasis (LCL or MCL). Although mean ELISA absorbance values were significantly higher for MCL sera than for LCL sera, absorbance could not be used as a reliable indicator of the clinical form of disease. Immunoblotting profiles were similar with sera from MCL and LCL. Pre-adsorption with heterologous trypanosomatid antigens indicated that recognition of antigens of about 56, 60, 66, 72, 88 and 110 kDa might be specific to the subgenus Viannia. In two-colour, sequential, dual ELISA-based immunoblotting, no antigens recognized only by sera from MCL patients were detected. After glucantime therapy, immunoblotting profiles with LCL sera were reduced both in intensity and in the range of antigens detected; a 104-kDa antigen was newly detected with post-treatment LCL sera. Overall, the results show the value of differential immunological detection strategies and support the close relationship between species of the subgenus Viannia but fail to indicate a prognostic antigen for MCL.