Improvements in routine xenodiagnosis with first instar Dipetalogaster maximus (Uhler 1894) (Triatominae).

First instar Dipetalogaster maximus proved as effective as third instar Triatoma infestans in detecting circulating Trypanosoma cruzi in patients with chronic infections examined in a routine xenodiagnostic laboratory. Since rearing costs are diminished, D. maximus has now replaced T. infestans as the xenodiagnostic agent in our laboratory. However, further work is needed to define the optimal conditions necessary when using this species in xenodiagnosis.

Clinical observations of unresponsive mucosal leishmaniasis.

We report the long-term clinical follow-up of two patients with unresponsive mucosal leishmaniasis due to Leishmania (Viannia) braziliensis from the Três Braços area in Bahia State, Brazil. Both were agricultural male workers with extensive upper respiratory mucosal involvement that was not cured with conventional and experimental therapy.

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.

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.

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.

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.

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.