Chagas disease: current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries

Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Brasília in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering Committee on Chagas Disease of the Special Program for Research and Training in Tropical Diseases of the World Health Organization (TDR), the objective was set to promote and finance research aimed at the development of new methods and tools to control this disease. The well known research institutions in Latin America were the key elements of a world wide network of laboratories that received - on a competitive basis - financial support for projects in line with the priorities established. It is presented the time line of the different milestones that were answering successively and logically the outstanding scientific questions identified by the Scientific Working Group in 1978 and that influenced the development and industrial production of practical solutions for diagnosis of the infection and disease control.

Taxonomic reports of Otobothrioidea (Eucestoda, Trypanorhyncha) from elasmobranch fishes of the southern coast off Brazil

Specimens of elasmobranch fishes, captured in the states of Paraná and Santa Catarina, of the southern coast off Brazil, represented by three families, four genera, and four species, were parasitized with otobothrioid trypanorhynch cestodes: Heptranchias perlo (Bonnaterre, 1788), Squalus sp. and Carcharhinus signatus (Poey, 1868) were parasitized with Progrillotia dollfusi Carvajal & Rego,1987; Prionace glauca (Linnaeus, 1758) with Molicola horridus (Goodsir, 1841) Dollfus, 1942. Details of internal morphology and/or scolex and/or proglottids surface ultrastructure, that expanded the description of M. horridus, through observations with lightfield, and/or scanning eletronic microscopy, are provided. The known geographical distribution for the species M. horridus is enlarged. P. dollfusi is reported for the first time in elasmobranchs.

High proportion of hepatitis C virus genotypes 1 and 3 in a large cohort of patients from Southern Brazil

Hepatitis C virus (HCV) isolates have been divided into six genotypes (1 to 6). The duration of hepatitis C standard treatment is 48 weeks for patients infected with HCV genotype 1 vs 24 weeks for those infected with genotypes 2 and 3. A total of 1544 HCV isolates from chronic patients living in the southern Brazilian states of Rio Grande do Sul (RS, n = 627) and Santa Catarina (SC, n = 917) were genotyped by restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products. In RS, 338 (53.9%; 95% CI 50.0 - 57.8%), 34 (5.4%; 95% CI 3.8 - 7.4%) and, 255 (40.7%; 95% CI 36.9 - 44.6%) samples were from genotypes 1, 2, and 3, respectively. In SC, 468 (51%; 95% CI 47.8 - 54.2%), 26 (2.9%; 95% CI 1.9 - 4.1%) and, 423 (46.1%; 95% CI 42.9 - 49.3%) samples were from genotypes 1, 2, and 3, respectively. Genotyping results were confirmed by direct nucleotide sequencing of PCR products derived from 68 samples, without any discrepancy between PCR-RFLP and nucleotide sequencing methods. In conclusion, almost half of the hepatitis C patients from South of Brazil are infected by genotypes 2 and 3 and, these results have important consequential therapeutic implications as they can be treated for only 24 weeks, not 48.

Bledius Leach from southern Brazil (Coleoptera, Staphylinidae, Oxytelinae)

Three species of Bledius Leach, 1819 are recognized from southern Brazil. A new species is described, B. hermani n. sp., from Paraná and Rio Grande do Sul States and B. fernandezi Bernhauer, 1939 is redescribed. The geographical distribution of B. bonariensis Bernhauer, 1912 and B. fernandezi are extended. A key to identification of Bledius from southern Brazil is also provided.

Benefits from ecological study methods to taxonomy of enchytraeids in southern Mata Atlântica

The objective of this work was to determine how taxonomy benefited from the ecological quantitative and site-based sampling methods in enchytraeids studies. Enchytraeids (small relatives of earthworms) were sampled in different phases of rain forest regeneration in the southern Mata Atlântica in Paraná, Brazil. The research combined ecological and taxonomic work, because enchytraeids are poorly studied and difficult to identify, and many new species were expected. The provision of large numbers of specimens enabled the test of species diagnoses by investigating the ranges of character variations in a larger series of specimens. Simplified species diagnoses adapted to the local conditions that allowed the identification of all specimens, juveniles included, were developed. Key characters and character states are presented for the three genera: Achaeta, Hemienchytraeus and Guaranidrilus. Among several new species, a rare species, possibly a remnant of the autochthonous forest fauna, was found and described.