Protein tyrosine phosphatases (PTPs) play an essential role in the regulation of cell differentiation in pathogenic trypanosomatids. In this study, we describe a PTP expressed by the non-pathogenic protozoan Trypanosoma rangeli (TrPTP2). The gene for this PTP is orthologous to the T. brucei TbPTP1 and Trypanosoma cruzi (TcPTP2) genes. Cloning and expression of the TrPTP2 and TcPTP2 proteins allowed anti-PTP2 monoclonal antibodies to be generated in BALB/c mice. When expressed by T. rangeli epimastigotes and trypomastigotes, native TrPTP2 is detected as a ~65 kDa protein associated with the parasite's flagellum. Given that the flagellum is an important structure for cell differentiation in trypanosomatids, the presence of a protein responsible for tyrosine dephosphorylation in the T. rangeli flagellum could represent an interesting mechanism of regulation in this structure.

In the present study, a fragment of the VP28 coding sequence from a Brazilian WSSV isolate (BrVP28) was cloned, sequenced and expressed in E. coli BL21(DE3) pLysS strain in order to produce the VP28 carboxyl-terminal hydrophilic region. The expression resulted in a protein of about 21 kDa, which was purified under denaturing conditions, resulting in a final highly purified BrVP28 preparation. The recombinant protein obtained can be used in several biotechnology applications, such as the production of monoclonal antibodies which could be used in the development of diagnostic tools as well as in the studies on the characterization of white spot syndrome virus (WSSV) isolated in Brazil.

Relatamos neste artigo o primeiro caso de megaesôfago determinado por infecção pelo Trypanosoma cruzi no Estado de Santa Catarina, região sul do Brasil. Uma paciente de 63 anos de idade com diagnóstico clínico presuntivo de doença de Chagas, apresentou exames de imagem (endoscopia e esofagograma) e imunológicos positivos. Além disso, foi realizado diagnóstico molecular com amostras de esôfago e sangue coletadas durante a cirurgia corretiva. A reação em cadeia da polimerase apresentou-se positiva para Trypanosoma cruzi nas amostras de esôfago e no creme leucocitário.

We report the first case of digestive tract pathology (megaesophagus) determined by Trypanosoma cruzi infection in Santa Catarina State, southern Brazil. A 63-year- old female had presumptive clinical diagnosis of Chagas' disease, which was confirmed by imaging (endoscopy and esophagogram) and immunological methods. Further molecular diagnosis was carried out with esophagus and blood samples collected during corrective surgery. Polymerase chain reaction tested positive for Trypanosoma cruzi in both esophagus and buffy coat samples.

The life cycle of Triatoma klugi Carcavallo, Jurberg, Lent & Galvão 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% of Group A and 67% 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% and 33% 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% 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.

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% and reaching 48.4% 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.

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% of the opossums captured in SCI and 45.2% 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.

Objetivando verificar a colonização de Panstrongylus megistus em ecótopos artificiais em Florianópolis foram examinados, de 1985 a 1992, 779 anexos peridomiciliares (524 galinheiros, 46 currais e 209 ranchos) em 9 localidades e 443 domicílios no distrito de Lagoa, todos na Ilha de Santa Catarina. Todo o ecótopo, incluindo forro e porão das casas, era examinado após aplicação de líquido insentífugo (Pirisa a 5%). A pesquisa nos anexos peri-domiciliares revelou 3 galinheiros e um rancho positivo no distrito de Lagoa, onde foram também encontrados 2 domicílios colonizados pelo P. megistus, com a captura de ovos, ninfas e adultos em todos os ecótopos. Pesquisas dirigidas foram realizadas em dois outros domicílios e em uma escola, nos quais os moradores haviam detectado anteriormente exemplares de P. megistus e, em todos os 3, foi confirmada a colonização pelo triatomíneo. Nos 9 ecótopos artificiais foram coletados 559 ovos, 305 ninfas e 24 adultos de P. megistus, com um índice de infecção pelo T. cruzi de 53,3% (182/329). Índice de infecção semelhante, de 56,5% (78/ 138), foi também encontrado nos adultos de P. megistus oriundos dos ecótopos silvestres e capturados nos domicílios pelos moradores, no período de 1983 a 1991. Os testes de precipitina revelaram, em 94,0% dos insetos examinados (170/181), sangue de uma única fonte alimentar e presença de sangue humano em 80,6% (25/31) dos adultos e em 5,8% (1/17) das ninfas capturados nos domicílios. Os resultados encontrados sugerem a necessidade de adoção de medidas de vigilância epidemiológica com a participação da comunidade, face o risco potencial de domiciliação do P. megistus.

The aim of this work was to verify the colonization of Panstrongylus megistus on artificial ecotopes in Florianópolis, in the Santa Catarina Island, South Brazil. For this purpose 443 houses of the Lagoa district and 779 house annexes (524 chicken-houses, 46 corrals and 209 storage-houses) in 9 different places were examined from 1985 to 1992. These ecotopes, which include ceilings and basements, were checked after application of dislodging liquid (Pirisa 5%). Colonization by P. megistus was verified in two houses, three chicken-houses and one storage-house of the Lagoa district, where eggs, nymphs and adults were collected. To verify local reports of P. megistus occurrence, another two houses and one school were investigated. The colonization at all of these places was confirmed. In the 9 artificial ecotopes examined, 559 eggs, 305 nymphs and 24 adults were collected. The infection rate of P. megistus by Trypanosoma cruzi was 55.3% (182/ 329). A similar infection rate of 56.5% (78/138) was obtained in adults of P. megistus from sylvatic ecotopes and in adults captured in the houses by the inhabitants between 1983 to 1991. Precipitin tests revealed blood from just one source in 94.0% of the insects (170/181). Human blood was found in 80.6% (25/31) of the adults and in 5.8% (1/17) of the nymphs captured in the houses. These results suggest the need to ally serious epidemiologic vigilance to the effort of the inhabitants in order to avoid the risk of domiciliation of P. megistus in the houses.