A clinical prediction rule for American cutaneous leishmaniasis in Colombia.

Neither parasitological nor molecular diagnosis of leishmaniasis is widely available in clinical settings where American cutaneous leishmaniasis (ACL) is endemic. Therefore four clinical prediction rules for ACL were developed which incorporated physical examination findings (clinical rule), physical examination and leishmanin skin test (LST) (clinical-LST rule), physical examination and historical information (clinical-historical rule), or physical examination, historical information and LST (clinical-historical-LST rule). One hundred parasitologically diagnosed ACL cases and 38 cases of chronic skin lesions of other aetiologies comprised the derivation set. The validation set consisted of 124 ACL cases and 35 patients with lesions of other aetiologies. Components of each rule were selected by bivariate analysis, then step-wise logistic regression. Sensitivity, specificity and efficiency were calculated for each score threshold; the threshold achieving greatest efficiency was selected for each rule. When these rules were applied to the validity set the sensitivity, specificity and efficiency were respectively: clinical 93%, 31%, 79%; clinical-LST 90%, 73%, 85.9%; clinical-historical 97%, 51%, 87%; clinical-historical-LST 92%, 70%, 87%. Inclusion of LST skin test consistently improved the specificity of the rules. Should a given clinical setting warrant optimizing either sensitivity or specificity alone, the rule thresholds can be adjusted. These and other prediction rules, once evaluated in other settings, should be incorporated into leishmaniasis control programmes.

Leishmanin skin test standardization and evaluation of safety, dose, storage, longevity of reaction and sensitization.

Leishmanin skin test (LST) antigens prepared from Leishmania braziliensis panamensis were compared with respect to sensitivity, specificity, and side effects. Within the dose range 0.5-3.0 x 10(5) promastigotes of L. b. panamensis and 10 x 10(5) promastigotes of combined L. amazonensis and L. b. panamensis, specificity in healthy controls was nearly 100% for all antigens. Sensitivity increased minimally with increasing dose. Lot-to-lot differences were small. Side effects, such as vesiculation and ulceration at the site of LST application increased with antigen dose. Storage under harsh conditions decreased LST potency but not sensitivity while storage at 2-8 degrees C affected neither potency nor sensitivity. Eighty-five percent of parasitologically diagnosed, LST-positive cases of leishmaniasis remained LST-positive when retested six months to three years later. The LST did not sensitive 19 healthy controls who were skin tested twice or thrice.

Mucosal disease caused by Leishmania braziliensis guyanensis.

Three Leishmania strains were isolated from cutaneous and mucosal lesions of a Colombian male. These strains, shown to be phenotypically identical based on isoenzyme polymorphisms and monoclonal antibody reactivity, were identified as Leishmania braziliensis guyanensis. Six clones of the mucosal strain were phenotypically identical to the 3 strains. The clinical presentation of the cutaneous lesions and the geographic origin of the infection were consistent with infection by L. b. guyanensis.