Etiologia da Tripanosom?ase em Hypostomus punctatus Valenciennes, 1840 (OSTEICHTHYES, LORICARIIDAE): taxonomia, preval?ncia e transmiss?o

• Author(s): Bara, Marta d' Agosto
• Date: 2020
• Origin: Oasisbr
• Subject(s): Medicina Veterin?ria; Medicina Veterin?ria
• Document Type: Master thesis
• Language: Portuguese

Description

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Coordena??o de Aperfei?oamento de Pessoal de n?vel Superior - CAPES

In order to evaluate the infection of a host population with trypanosomes, 303 Hypostomus punctatus Valenciennes were studied during the period January to December of 1982. These fish were captured in the A?u Lake of the Federal Rural University of Rio de Janeiro, Rio de Janeiro State. The prevalence of trypanosomes was 100% by all three methods used: blood smears, microhaematocrit centrifugation or thick smears between slldes and coverslips. In fine blood smears stained with Giemsa, 72.9% of the positives were detected. The smallest size class of fishes (7 to 12 cm) had the highest mean intensitv of infection: 9,6 x 105 trypanosomes/ml of blood. The intensity of infection decreased together with the increase in the size of the fish, reaching 1.2 x 105 trypanosomes/ml blood in the largest fish of 28 to 33 cm. Two species of pleomorphic trypanosomes were identified: Trypanosoma (Haematomonas) chagasi Horta, 1910 and Trypanosoma (Isomonasoma) guaibensis Froes, Fortes Lima & Leite, 1978, the latter being ? new host record. Isomonasoma was proposed as a new subgenus., while Haematomonas Mitrophanow, 1883 was reduced from genus to sbgenus. Leeches removed for the fish were dissected and were found to be infected with trypanosomes in various stages of development. Trypanosomes were transmitted by leeches to an uninfected fish from another area. The incrimination of the leech Diplobdella sp. is the first reference to a fish trypanosome vector in Brazil.

Objetivando-se avaliar infec??o por tripanosomas em uma popula??o de hospedeiros, foram examinados, de janeiro a dezembro de 1982, 303 cascudos-pedra, Hypostomus punctatus Valenciennes, capturados no Lago A?u da Universidade Federal Rural do Rio de Janeiro, Estado do Rio de Janeiro. A preval?ncia de tripanosomas constatada pelo exame de sangue fresco, quer pela centrifuga??o de microhemat?crito ou por gota de sangue entre l?mina e lam?nula, foi de 100%. Pelo exame de esfrega?os sangu?neos finos corados com Giemsa, detectaram-se 72,9% de positivos. Os peixes de menor comprimento, classe de 7 a 12 cm, apresentaram a maior intensidade m?- dia de infec??o, que foi de 9,6 x l05 tripanosomas/ml de sangue; a intensidade da infec??o decresceu progressivamente ao aumento de tamanho dos peixes, baixando a 1,2 x l05 tripanosomas/ml de sangue, entre os peixes maiores, de 28 a 33 cm. Foram identificadas duas esp?cies de tripanosomas pleom?rficos: Trypanosoma (Haematomonas) chagasi Horta, 1910 e Trypanosoma (Isomonasoma) guaibensis Fr?es, Fortes, Lima & Leite, 1978. H. punctatus foi, pela primeira vez, referido como hospedeiro de T. (I.) guaibensis. Isomonasoma foi proposto como novo subg?nero, enquanto Haematomonas Mitrophanow, 1883 foi reduzido de g?nero a subg?nero. As sanguessugas capturadas sobre os cascudos pedra foram dissecadas e apresentaram-se infectadas por tripanosomas em diversas etapas de desenvolvimento. Tripanosomas foram transmitidos atrav?s de sanguessugas a um cascudo-pedra n?o infectado, proveniente de outro local. A incrimina??o da sanguessuga Diploddella sp. ? a primeira refer?ncia a um veror de tripanosomas a peixes no Brasil.