Abstract INTRODUCTION: Chagas disease surveillance requires current knowledge on synanthropic triatomines. We analyzed the occurrence and Trypanosoma cruzi infection rates of triatomine bugs in central Brazil, during 2012-2014. METHODS: Triatomines were collected inside or around houses, and T. cruzi infection was determined by optical microscopy and conventional/quantitative polymerase chain reaction. RESULTS: Of the 2706 triatomines collected, Triatoma sordida was the most frequent species in Goiás State, whereas Panstrongylus megistus predominated in the Federal District. Parasites identified were T. cruzi, T. rangeli, and Blastocrithidia sp. CONCLUSIONS: P. megistus and T. sordida sustained the risk of T. cruzi transmission to humans in central Brazil.

INTRODUÇÃO: A competência vetorial de triatomíneos é determinada a partir de estudos sobre biologia e comportamento alimentar em condições de campo e/ou laboratório. Fatores como número de picadas, quantidade de sangue ingerido e tempo de defecação têm implicações na transmissão de tripanosomatídeos. Parâmetros biológicos e comportamentais de Rhodnius neglectus e R. robustus foram comparados experimentalmente para estimar diferenças no potencial de transmissão de tripanosomatídeos. MÉTODOS: Os triatomíneos foram observados diariamente para determinar o período de desenvolvimento ninfal, mortalidade, detecção da fonte alimentar, número de picadas, tempo do repasto sanguíneo, quantidade de sangue ingerido, tempo entre o final do repasto e a primeira defecação e frequência de defecação. RESULTADOS: Apesar do período ninfal de R. neglectus (156,4 ± 25,05d) ter sido menor que o de R. robustus (204,7 ± 13,22d), a mortalidade foi similar entre as espécies (63,8 e 65%, respectivamente). R. robustus e R. neglectus detectaram rapidamente a fonte alimentar, especialmente no primeiro estádio (2,5 e 1,6min, respectivamente). Apesar do tempo de repasto sanguíneo ter sido similar entre as espécies, R. robustus ingeriu em média uma maior quantidade de sangue em todos os estádios, com maiores valores para as ninfas V. As ninfas de R. neglectus picaram mais vezes as fontes alimentares, defecaram mais rápido e mais frequentemente que as de R. robustus. CONCLUSÕES: Sob as condições de laboratório usadas, R. neglectus possui um maior potencial para transmissão de Trypanosoma cruzi e T. rangeli que R. robustus, atributo que deve ser avaliado em infecções experimentais.

INTRODUCTION: The vector competence of triatomine insects is determined by studying their biology and feeding behavior under field and/or laboratory conditions. Factors including the number of bites, the amount of blood ingested and defecation time have implications for trypanosome transmission. The biological and behavioral parameters of Rhodnius neglectus and R. robustus were compared under experimental conditions to estimate differences in the potential transmission of trypanosomes. METHODS: The insects were observed daily to determine the period of nymphal development, mortality, detection of food source, number of bites, time of blood meal intake, amount of blood ingested, time elapsed between the end of the meal and the first defecation and the frequency of defecation. RESULTS: Although the nymphal development of R. neglectus (156.4 ± 25.05d) was lower than that of R. robustus (204.7 ± 13.22d), the mortality between species was similar (63.8 and 65% respectively).R. robustus and R. neglectus quickly located the food source, especially in the first instar (2.5 and 1.6 min, respectively). Although the time of blood meal intake was similar between the species, R. robustus ingested a larger amount of blood on average at all stages and exhibited higher values for the fifth instar. Nymphs of R. neglectus bit more frequently, and they defecated faster and more often than those of R. robustus. CONCLUSIONS: Under laboratory conditions, R. neglectus has a greater potential for transmission of Trypanosoma cruzi and T. rangeli than does R. robustus, an attribute that should be further evaluated in experimental infections.

Psammolestes tertius Lent & Jurberg, 1965 is a sylvatic triatomine bug species that occurs in thornbird nests in Brazil. We studied infestation of 527 nests of Phacellodomus rufifrons Wied, 1821 and Phacellodomus ruber Vieillot, 1817 by P. tertius in eight Brazilian states across the Cerrado and Caatinga ecoregions. Psammolestes tertius occurred in 44% of the nests, mainly in those of P. ruber. Overall, 3,261 specimens (52% nymphs) were captured, with an average of 14 bugs per infested nest (range 1-75). While P. tertius occurrence and age structure (percentage of nymphs) were similar in Cerrado and Caatinga nests, infestation intensity (bugs/infested nest) was higher in the Cerrado. Last-stage nymphs and adults were predominant in P. tertius populations from both P. ruber and P. rufifrons nests. The results indicate that Phacellodomus nests are favourable habitats for P. tertius in the open/dry ecoregions of Brazil. The percentage of adult P. tertius specimens (48%) was higher than that observed in other triatomine species (usually less than 5% under either experimental or natural conditions), suggesting that adult bugs tend to remain in thornbird nests. The stable blood supply provided by resident/breeding birds would favor steady P. tertius infestation of thornbird nests across Brazilian Cerrado and Caatinga ecoregions.

FUNDAMENTOS: O PCR tem alta sensibilidade no diagnóstico da LTA, mas é caro e distante da prática. A cultura e o esfregaço são práticos, mas pouco sensíveis. OBJETIVO: O objetivo deste trabalho foi comparar os dois últimos métodos, buscando maior sensibilidade e menor custo. MÉTODOS:Foram comparados três meios de cultura no isolamento de leishmânia: Difco agar sangue + Schneider + soro bovino fetal (20%); Difco agar sangue + Schneider + urina humana (2%); Schneider + urina humana (2%). Foram comparadas, também, duas técnicas de pesquisa de amastigotas: esfregaço realizado com biópsia, ou raspado através de palito (matchstick). RESULTADOS: Os índices de positividade e contaminação (29 a 33% e 8 a 11%, respectivamente, p>0.05) foram semelhantes na comparação dos cultivos. Os esfregaços com biópsia, ou palito também não tiveram diferenças significativas (14 e 19%, respectivamente, p> 0,05). A Leishmania (Viannia) braziliensis predominou. CONCLUSÃO: No Brasil, a urina pode substituir o soro fetal bovino. Há vantagem na relação custo/benefício. A urina não tem custo enquanto 500ml de soro bovino fetal custa 185 dólares.

BACKGROUND: PCR is a highly sensitive procedure for the diagnosis of LTA, but it is expensive and not readily available. Culture and smearing are practical, but they lack sensitivity. OBJECTIVE: The objective of this work is to compare the latter two methods in order to achieve a higher sensitivity at a lower cost. METHOD: Three culture media were compared in the process of isolating leishmaniasis: blood Agar Difco + Schneider + 20% fetal calf serum; Difco + Schneider + human sterile urine (2%); Schneider with sterile human urine (2%). Moreover, two techniques were compared for the demonstration of amastigotes: biopsy performed with smears, or matchstick scrapping RESULTS: The positivity and contamination indices (29-to-33% and 8-to-11%, respectively, p>0.05) were similar when comparing the cultures. The smears carried out by biopsy or the matchstick scrapping procedure had no significant differences (14 and 19%, respectively, p>0.05). Leishmania (Viannia) braziliensis predominated. CONCLUSION: In Brazil, urine may substitute fetal calf serum. The cost-to-benefit ratio is advantageous. Urine has no cost, while the market value of 500 ml of fetal calf serum is $US 185.

In a study of 51 stocks of Leishmania isolated from patients with cutaneous leishmaniasis in Três Braços, Bahia, Brazil 49 were characterized as L. braziliensis braziliensis. Only two L. mexicana stocks were identified. One was subspeciated as L. mexicana amazonensis. The other differed from this species and to date remains unspeciated. The biological parameters, isoenzyme analysis and monoclonal antibody findings relating to these two strains are discussed. Transmission of parasites of the mexicana complex to man have been rare in this region during the 8 years of study of the human infection.

Del estúdio de 51 stocks de Leishmania aislados de pacientes humanos de leishmaniasis cutaneomucosa en Três Braços, Bahia, Brasil, los autores describen, en detalle, el análisis de los dos únicos stocks de L. mexicana, identificando uno de ellos como L. mexicana amazonensis. El otro aislado permanece en posición taxonómica no definida pues considerándosele como un miembro de L. mexicana, encuéntranse dificultades para su identificación subespecífica. Evaluan también los parâmetros biológicos e isoenzimáticos y discuten el papel de los anticuerpos monoclonales en la tipificación de éstos stocks. Los autores remarcan la rareza de la transmisión de parásitos del complejo L. mexicana en esta región, aun cuando estudien epidemiológicamente por mais de 8 anos la infección humana.