Leishmaniasis is a neglected disease that affects millions of people worldwide, and special attention should be given to treatment because the available drugs have limitations, which can lead to low therapeutic adherence and parasitic resistance. This study evaluated the activity of the bioactive naphthoquinones, lapachol and β-lapachone, against Leishmania amazonensis. The cell alterations were evaluated in vitro on promastigote and amastigote forms. The lethal dose (LD50) at 24, 48, and 72 h on the promastigote's forms using lapachol was 75.60, 72.82, and 58.85 μg/mL and for β-lapachone was 0.65, 1.24, and 0.71 μg/mL, respectively. The naphthoquinones significantly inhibited the survival rate of L. amazonensis amastigotes at 83.11, 57.59, and 34.95% for lapachol (82.28, 41.14, and 20.57 µg/mL), and 78.49, 83.25, and 80.22% for β-lapachone (3.26, 1.63, and 0.815 µg/mL). The compounds on the promastigote's forms led to the loss of mitochondrial membrane potential, induced changes in the integrity of the membrane, caused damage to cells suggestive of the apoptotic process, and showed inhibition of tumor necrosis factor (TNF)-α and interleukin (IL)-6 production. The results showed that these naphthoquinones are promising candidates for research on new drugs with anti-Leishmania activity derived from natural products.

Investigou-se a infecção por parasitas do complexo Leishmania braziliensis em 50 cães da cidade de Maringá, PR, onde ocorreram casos humanos de leishmaniose tegumentar americana (LTA), entre agosto e dezembro de 2006. Os casos humanos de LTA ocorreram nos anos de 2003 a 2004. Nenhum animal apresentou lesão, mas 12 (24,0%) tinham sorologia e/ou PCR positivas, e a positividade tanto da IFI como da PCR foi de 14,0%. Trinta e cinco animais eram de residências, e oito deles (22,8%) tiveram testes laboratoriais para LTA positivos. Os outros 15 eram cães errantes, sendo que quatro deles (26,7%) apresentaram PCR positiva. A presença de animais com infecção assintomática por Leishmania em área onde a LTA é endêmica pode ser um indicador do potencial de sua transmissão para o homem e uma referência para a implantação de medidas de controle e prevenção da doença.

The infection by Leishmania braziliensis complex was studied in 50 dogs from Maringá, PR, where American Cutaneous Leishmaniasis (ACL) in humans have been detected. Data were collected from August to December 2006 in an area in which ACL cases in humans were reported from 2003 to 2004. Indirect immunofluorescent test (IIF) and polymerase chain reaction (PCR) were applied. No lesions were found in the animals, although 12 (24.0%) had positive IIF and/or PCR. Positiveness was 14.0% for IIF and PCR. Lab tests showed that eight (22.8%) out of the 35 home animals were ACL positive. The other 15 animals were stray dogs, out of which four (26.7%) were PCR positive. The appearance of asymptomatic Leishmania-infected dogs in an ACL endemic area may be an indicator of ACL transmission potential for humans and a reference for the establishment of control measures and disease prevention.

Estudaram-se 92 cães errantes com o objetivo de comparar a imunofluorescência indireta (IFI) e a aglutinação direta (AD) na investigação da leishmaniose tegumentar americana (LTA) canina, no período de outubro de 1999 a novembro de 2001. Os animais foram examinados quanto à presença de lesões e submetidos à intradermorreação de Montenegro (IDRM) e à pesquisa de anticorpos anti-Leishmania por IFI e AD. A IFI apresentou sensibilidade de 78,9% e especificidade de 93,8% (título >40), e a AD sensibilidade de 57,9% e especificidade de 68,8% (título >80). Dois cães apresentavam lesão, mas a pesquisa do parasito foi negativa. A IDRM, realizada em 89 cães, foi positiva em três (3,4%). Trinta e quatro cães (37,0%) foram positivos para a IFI, 61 (66,3%) para a AD e 69 (75,0%) para a IFI e/ou a AD. Dos cães com a IFI positiva, sete eram de Floresta, 13 de Maringá, 12 de Leópolis, um de São Jorge do Ivaí e um (50,0%) de Campo Mourão. Os resultados sugerem o contato prévio desses animais com o parasito.

Ninety-two stray dogs were studied in order to compare indirect immunofluorescence (IIF) and direct agglutination (DA) in the investigation of American cutaneous leishmaniasis (ACL), from October 1999 to November 2001. The dogs were evaluated for the presence of lesions, and submitted to the Montenegro skin test (MST) and the search for anti-Leishmania antibodies by IIF and DA. IIF showed 78.9% sensitivity and 93.8% specificity (titers >40), and DA presented 57.9% sensitivity and 68.8% specificity (titers >80). In two dogs there were lesions, but the parasite was not detected. The MST was positive in 3 (3.4%) out of 89 dogs. Thirty-four (37.0%) dogs showed anti-Leishmania antibodies through IIF, 61 (66.3%) through DA, and 69 (75.0%) through IIF and/or DA. Of the dogs with positive IIF, 7 came from the municipal areas of Floresta, 13 of Maringá, 12 of Leópolis, 1 of São Jorge do Ivaí and 1 (50.0%) of Campo Mourão. These data suggest previous contact of these animals with the parasite.