Roberto Aguilar Machado Santos Silva

Genetic relatedness among Trypanosoma evansi stocks by random amplification of polymorphic DNA and evaluation of a synapomorphic DNA fragment for species-specific diagnosis.

In this study we employed randomly amplified polymorphic DNA patterns to assess the genetic relatedness among 14 Brazilian Trypanosoma evansi stocks from domestic and wild hosts, which are known to differ in biological characteristics. These akinetoplastic stocks were compared with one another, to three Old World (Ethiopia, China and Philippines) dyskinetoplastic stocks of T. evansi, and also with Trypanosoma equiperdum, Trypanosoma brucei brucei, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. Randomly amplified polymorphic DNA analysis showed limited heterogeneity in T. evansi stocks from different hosts and geographical regions of the world, or in other species of the subgenus Trypanozoon. However, minor variations generated random amplification of polymorphic DNA analysis disclosed a pattern consisting of a unique synapomorphic DNA fragment (termed Te664) for the T. evansi cluster that was not detected in any other trypanosome species investigated. Pulsed field gel electrophoresis analysis demonstrated that the Te664 fragment is a repetitive sequence, dispersed in intermediate and minichromosomes of T. evansi. Based on this sequence, we developed a conventional PCR assay for the detection of T. evansi using crude preparations of blood collected either on glass slides or on filter paper as template DNA. Our results showed that this assay may be useful as a diagnostic tool for field-epidemiological studies of T. evansi.

Molecular and morphological studies of Brazilian Trypanosoma evansi stocks: the total absence of kDNA in trypanosomes from both laboratory stocks and naturally infected domestic and wild mammals.

The kinetoplast DNA (kDNA) minicircle molecules of 14 Brazilian stocks of Trypanosoma evansi were studied by morphological approaches (Giemsa and 4′-6′-diamidino-2-phenylindole staining and transmission electron microscopy) and molecular approaches (probing with an oligonucleotide complementary to the minicircle origin of replication and polymerase chain reaction amplification of a minicircle sequence). All methods indicated the absence of both a typical kinetoplast and kDNA minicircles, even in a very small number of parasites of a single stock or in small numbers of copies of molecules per cell. We did not detect any altered kDNA molecules. There were no kDNA molecules in either old or new stocks of T. evansi maintained by successive passages in mice. Similarly, no kDNA minicircles were detected in trypanosomes in blood smears from naturally infected domestic and wild animals. Thus, the total absence of kDNA in Brazilian stocks of T. evansi from both domestic and wild mammals is probably the natural state of Brazilian T. evansi.

Outbreak of trypanosomiasis due to Trypanosoma vivax (Ziemann, 1905) in bovines of the Pantanal, Brazil.

Laboratório de Ecopatologia, EMBRAPA, Centro de Pesquisa Agropecuária do Pantanal, Rua 21 de Setembro 1880, 79720-900 Corumbá, MS, Brasil *Associação Brasileira de Criadores de Cavalo Pantaneiro, Av. Joaquim Murtinho s/n, 78175-000 Poconé, MT, Brasil **Instituto de Defesa Agropecuária do Estado de Mato Grosso, Av. BEdificio Ceres 2o and., Cuiabá, MT, Brasil ***Delegacia Federal de Agricultura, Abastecimento e Reforma Agrária do Mato Grosso, Seção Sanidade Animal, Alameda Anibal Molina s/n, 78115-901 Varzea Grande, MT, Brasil ****Laboratório Ultracenter, Rua General Vale 350, 78000-000 Cuiabá, MT, Brasil

Pathogenesis of Trypanosoma evansi infection in dogs and horses: hematological and clinical aspects

Trypanosoma evansi caused severe anemia in horses and pronounced leukopenia in dogs, both naturally infected. The horses presented microcytic normochromic anemia and the dogs showed microcytic hypochromic anemia. The clinical signs observed were fever, anemia, edema of the legs and lower parts, weakness and inappetence. Light microscopic studies demonstrated that Trypanosoma evansi produced several alterations in erythrocytes of dogs and horses. These pathologic changes included vacuolation, acanthocytes, dacrocytes, codocytes, microspherocytes and bizarre shapes. Mature erythrocyte were observed adhered to trypanosomes. Erythrophagocytosis was also demonstred.

Circulation of Eastern equine encephalitis, Western equine encephalitis, Ilhéus, Maguari and Tacaiuma viruses in equines of the Brazilian Pantanal, South America

Neutralizing antibodies to EEE (6.7%), WEE (1.2%), ILH (26.6%), MAG (28.2%) and TCM (15.7%) viruses were found in sera of 432 equines of the Brazilian Pantanal, area where undiagnosed horse deaths are frequently observed. A 4-fold rise in CF titer to EEE virus was detected in acute and convalescent sera of an encephalitis horse sacrificed in 1992. Antibodies to EEE, ILH, MAG and TCM viruses were detected in horses less than 2 years old indicating recent circulation of these viruses in the Pantanal. The evidence of recent equine encephalitis associated with rising CF titer to EEE warrants a more intensive study with attempts to isolate virus from horses with clinical manifestations of encephalitis.

Trypanosoma evansi control and horse mortality in the Brazilian Pantanal

The impact of three treatment strategies for Trypanosoma evansi control on horse mortality in the Brazilian Pantanal based on four size categories of cattle ranches is explored. The regions 49,000 horses are indispensable to traditional extensive cattle ranching and T. evansi kills horses. About 13% of these horses would be lost, annually, due to T. evansi if no control were undertaken. One preventive and two curative treatment strategies are financially justifiable in the Pantanal. The best available technology for the treatment of T. evansi from a horse mortality perspective is the preventive strategy, which spares 6,462 horses, annually. The year-round cure spares 5,783 horses, and the seasonal cure saves 5,204 horses on a regional basis relative to no control strategy. Regardless of the strategy adopted, 39% of the costs or benefits fall to the largest ranches, while 18% fall to the smallest ranches.

Outbreaks of trypanosomosis due to Trypanosoma vivax in cattle in Bolivia

This paper reports the first occurrence of bovine trypanosomosis due to Trypanosoma vivax in Bolivia. T. vivax was identified in thin blood smears of 159 cattle from the Provinces of Velaco (57), Nuflo de Chavez (20), Guayaros (30) and Chiquitos (52), and in 86.20% of 29 cattle from Laguna Concepción examined by microhematocrit test. The clinical signs observed were fever, anemia, abortion, progressive weakness, loss of appetite, lethargy, substantial weight loss in a relatively short time, and progressive emaciation.

Ocorrência de lesões em carcaças de bovinos de corte no Pantanal em função do transporte

This study aimed to assess the influence of transport on the occurrence of carcass bruising of cattle slaughtered in the Pantanal, by quantifying the number and size of bruises, locating the frequency of occurrence of bruises in the main commercial cuts standardized for interne market. From a total of 121 carcasses assessed, 102 (84.3%) had one or more bruises, totaling 270 bruises, which resulted in the removal of 56.1kg meat. The frequency of carcass bruises of cattle showed significant difference, according to the conditions of transport. The highest proportions of bruises found in animals submitted to road transport for more than one hour in distances longer than 70km, a great part of which on dirty toads. The conclusion is that the animals submitted to the successive series of handling and transported on dirty roads for long distances caused the highest proportion of bruises, whereas the animals submitted to lot IV presented the highest number of bruises.

Bovine trypanosomiasis in Bolivian and Brazilian lowlands

Laboratorio de Ecopatologia, EMBRAPA, Centro de Pesquisa Agropecuaria do Pantanal, Rua 21 de Setembro 1880, 79320-900 Corumba, MS, Brasil *Federacion de Ganaderos de Santa Cruz, Av. Ejercito Nal. esq. Soliz de Olguin, Casilla N° 1508, Santa Cruz de la Sierra, Bolivia **Laboratorio de Investigacion y Diagnostico Veterinario, Av. Ejercito Nal. 153, Casilla N° 29, Santa Cruz de la Sierra, Bolivia ***Consultoria Economica, EMBRAPA/PROMOAGRO, Corumba, MS, Brasil ****Universidade Federal de Mato Grosso do Sul, Av. Rio Branco 1270, Corumba, MS, Brasil

Manejo pré-abate de bovinos de corte no pantanal, Brasil

Faculdade de Medicina Veterinaria (FMVZ) Universidade Estadual Paulista (UNESP), Rua Dr. Jose Barbosa de Barros, 835, Jardim Paraiso. CEP 18609-085. Botucatu, SP