Outbreak of autochthonous canine visceral leishmaniasis in Santa Catarina, Brazil / Surto autóctone de leishmaniose visceral canina no Estado de Santa Catarina

The present study reports the first outbreak of autochthonous canine visceral leishmaniasis in Florianópolis, Santa Catarina, southern Brazil. Following the report of two cases of CVL, the Control Center of Zoonotic Diseases conducted a serological survey by ELISA and IFAT assays in seven districts of the Santa Catarina Island. Eleven seropositive dogs of autochthonous transmission were used in the present study. Infection by Leishmania sp. was confirmed by parasitological examination of bone marrow, liver, spleen and lymph nodes, culture in Schneider's medium and PCR. Leishmania sp. isolates were characterized by PCR-RFLP and hybridization with specific probes, allowing for the identification of Leishmania infantum. Autochthonous transmission of this disease in an area with high tourist traffic presents a major public health concern and signifies the emergence of an important zoonosis in southern Brazil. Therefore, the implementation of surveillance and control measures is imperative to prevent the spread of the disease among the canine population as well as transmission to the human population.

O presente estudo relata o primeiro surto autóctone de leishmaniose visceral canina (LCV) em Florianópolis, Santa Catarina, Brasil. Durante levantamento soro-epidemiológico realizado pelo Centro de Controle de Doenças Zoonóticas (CCZ) envolvendo 2.124 cães, 29 (1,37%) foram soropositivos para VL (ELISA + RIFI). Onze cães positivos por transmissão autóctone foram utilizados no presente estudo. A confirmação da infecção por Leishmania sp. foi realizada pelo exame parasitológico da medula óssea, fígado, baço e linfonodos, cultura em meio Schneider e PCR. Os isolados de Leishmania sp. foram caracterizados por PCR-RFLP e hibridação com sondas específicas, permitindo a identificação de Leishmania infantum. A transmissão autóctone da LCV em uma área com grande fluxo turístico como Florianópolis representa um preocupante risco à saúde pública e o surgimento de uma importante zoonose no sul do Brasil. Neste contexto, a implementação de medidas de vigilância e controle da doença são fundamentais para evitar a propagação da doença entre a população canina, bem como a transmissão para a população humana.

Trypanocidal activity of coumarins and styryl-2-pyrones from Polygala sabulosa A.W. Bennett (Polygalaceae) / Atividade tripanocida de cumarinas e estiril-2-pironas de Polygala sabulosa A.W. Bennett (Polygalaceae)

A bioatividade das frações e compostos obtidos de Polygala sabulosa contra as formas epimastigota, tripomastigota sanguínea e amastigota de Trypanosoma cruzi foram avaliadas in vitro. Frações diclorometano e acetato de etila mostraram potente atividade tripanocida sob as formas epimastigotas (IC50 < 10,4 µg/mL). Análises por cromatografia em camada delgada destas frações confirmaram a presença de compostos previamente descritos (dihidroestiril-2-pironas, estiril-2-pironas e 6-metoxi-7-preniloxicumarina). Após o fracionamento da fração diclorometano por cromatografia em coluna, obteve-se o composto α-espinasterol e da fração acetato de etila obtiveram-se os compostos apigenina, quercetina e uma quercetina-3- O-glicosídeo, todos descritos pela primeira vez para o gênero Polygala. 4-metoxi-6-(11,12-metilenodioxi-14-metoxidihidroestiril)-2-pirona, 4-metoxi-6-(11,12-dimetoxi-14-metoxiestiril)-2-pirona, 6-metoxi-7-preniloxicumarina e quercetina-3- O-glicosídeo mostraram fraca atividade contra a forma tripomastigota sanguínea (IC50 < 1008,6 µg/mL). A cumarina prenilada foi o composto mais ativo contra ambas as formas epimastigota e tripomastigota, com IC50 10,5 e 88,2 µg/mL, respectivamente. A atividade hemolítica e a toxicidade celular de cada composto foram também avaliadas. Além disso, 4-metoxi-6-(11,12-metilenodioxi-14-metoxidihidroestiril)-2-pirona e 6-metoxi-7-preniloxicumarina reduziram em quatro vezes a infecção em ratos por Vero Cells nas concentrações de 100 e 50 µg/mL respectivamente. Esses resultados mostram, pela primeira vez, a atividade de compostos de P. sabulosa contra T. cruzi.

Bioactivity of fractions and compounds obtained from Polygala sabulosa against Trypanosoma cruzi epimastigote, blood trypomastigote and amastigote forms were evaluated in vitro. Dichloromethane and ethyl acetate fractions showed a strong trypanocidal activity on epimastigotes (IC50 < 10.4 µg/mL). Chromatographic analysis by TLC of these fractions confirmed the presence of previously described compounds (dihydrostyryl-2-pyrones, styryl-2-pyrones and 6-methoxy-7-prenyloxycoumarin). The dichloromethane fraction was fractioned by silica gel column chromatography to afford the compound α-spinasterol and the ethyl acetate fraction yielded apigenin, quercetin and a quercetin-3-O-glucoside, being the first description for the Polygala genus. 4-Methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone, 4-methoxy-6-(11,12-dimethoxystyryl)-2-pyrone, 6-methoxy-7-prenyloxycoumarin and quercetin-3-O-glucoside showed a weak activity against blood trypomastigotes (IC50 < 1008.6 µg/mL). The prenylated coumarin was the most active compound against both epimastigote and trypomastigote forms, IC50 10.5 and 88.2 µg/mL, respectively. The hemolytic activity and cell toxicity of each active compound was also assessed. Furthermore, 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone and 6-methoxy-7-prenyloxycoumarin reduced 4 times the T. cruzi infection rate for Vero cells at 100 and 50 µg/mL, respectively. These results show for the first time active compounds against T. cruzi in P. sabulosa.

Biology of Triatoma klugi Carcavallo, Jurberg, Lent & Galväo 2001 (Heteroptera: Reduviidae) under laboratory conditions: effects of eistinct blood sources and susceptibility to Trypanosoma cruzi and Trypanosoma rangeli

The life cycle of Triatoma klugi Carcavallo, Jurberg, Lent & Galväo 2001 was compared under laboratory conditions using two groups of the F1 generation obtained from field-collected bugs. Among the 100 nymphs weekly fed on mice (Group A) or chicken (Group B), 77 percent of Group A and 67 percent of Group B reached the adult stage, and the mean time from the first nymphal stage to adult was 190.08 ± 28.31 days and 221.23 ± 40.50, respectively. The average span in days for each stage per group and the number of blood meals required for each stage were also evaluated. The overall mortality rate was 23 percent and 33 percent for Groups A and B, respectively. The mean number of eggs laid per month in a three-month period was of 56.20, 51.70 and 73.20 for Group A, and 64.50, 53.50 and 38.71 for Group B. Despite the blood source, comparative analysis revealed no statistically significant differences in the life cycle of T. klugi under laboratory conditions. Infection rates over 60 percent were observed for both Trypanosoma cruzi strains tested. Even revealing high infection rates of the hemolymph by T. rangeli strains, T. klugi revealed no salivary gland infections and was not able to transmit the parasite

Trapping Triatominae in silvatic habitats

Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20 percent and reaching 48.4 percent for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system

Trypanosoma cruzi infection in Didelphis marsupialis in Santa Catarina and Arvoredo Islands, Southern Brazil

Between 1984 and 1993 the prevalence of the Trypanosoma cruzi infection in opossums (Didelphis marsupialis) was studied in Santa Catarina and Arvoredo Islands, State of Santa Catarina, Brazil. The association of the triatomine bug Panstrongylus megistus with opossums nests and the infection rate of these triatomines by T. cruzi was also studied. Thirteen different locations were studied in Santa Catarina Island (SCI), in which 137 D. marsupialis were collected. Sixty two opossums were collected at the Arvoredo Island (AI), located 12 miles north from SCI. All captured animals were submitted to parasitological examinations that revealed the presence of T. cruzi in 21.9 percent of the opossums captured in SCI and 45.2 percent among opossums captured in the AI. The presence of P. megistus was detected in most of the D. marsupialis nests collected in the SCI, however, in the non-inhabited AI only eight triatomines were collected during the whole study. The presence of T. cruzi-infected D. marsupialis associated with P. megistus in human dwellings in the SCI, and the high infection rate of D. marsupilais by T. cruzi in the absence of a high vector density are discussed

A simplified method for sample collection and DNA isolation for polymerase chain reaction detection of Trypanosoma rangeli and Trypanosoma cruzi in triatomine vectors

Due to the overlapping distribution of Trypanosoma rangeli and T. cruzi in Central and South America, sharing several reservoirs and triatomine vectors, we herein describe a simple method to collect triatomine feces and hemolymph in filter paper for further detection and specific characterization of these two trypanosomes. Experimentally infected triatomines feces and hemolymph were collected in filter paper and specific detection of T. rangeli or T. cruzi DNA by polymerase chain reaction was achieved. This simple DNA collection method allows sample collection in the field and further specific trypanosome detection and characterization in the laboratory

Characterization of Trypanosoma rangeli strains isolated in Central and South America : an overview

Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies comparing T. rangeli strains isolated in Santa Catarina with others isolated in Colombia, Honduras and Venezuela. The different methods used include indirect immunofluorescence and western blot assays, lectin agglutination, isoenzyme electrophoresis and random amplified polymorphic DNA analysis, triatomine susceptibility, in vitro cell infection assays, and mini-exon gene analysis.