First record of Trypanosoma sp. (Protozoa: Kinetoplastida) in tuvira (Gymnotus aff. inaequilabiatus) in the Pantanal wetland, Mato Grosso do Sul State, Brazil

Primeiro registro de Trypanosoma sp. (Protozoa: Kinetoplastida) em tuvira (Gymnotus aff. inaequilabiatus) no Pantanal, Mato Grosso do Sul, Brasil

RESEARCH NOTE

First record of Trypanosoma sp. (Protozoa: Kinetoplastida) in tuvira (Gymnotus aff. inaequilabiatus) in the Pantanal wetland, Mato Grosso do Sul State, Brazil

Primeiro registro de Trypanosoma sp. (Protozoa: Kinetoplastida) em tuvira (Gymnotus aff. inaequilabiatus) no Pantanal, Mato Grosso do Sul, Brasil

Santiago Benites de Pádua^I; Márcia Mayumi Ishikawa^II; Fabiana Satake^III; Gabriela Tomas Jerônimo^IV; Fabiana Pilarski^I

^ICentro de Aquicultura, Universidade Estadual Paulista – UNESP

^IIEmbrapa Agropecuária Oeste, Empresa Brasileira de Pesquisa Agropecuária – EMBRAPA

^IIICentro de Ciências Agrárias, Universidade Federal da Paraíba – UFPB

^IVLaboratório AQUOS, Departamento de Aquicultura, Universidade Federal de Santa Catarina – UFSC

^{Corresponding author}

ABSTRACT

The blood infection by Trypanosoma sp. in tuvira (Gymnotus aff. inaequilabiatus) from the Pantanal wetland was reported in this study. Ten fish from the Paraguay River in the Pantanal were evaluated for the presence of hemoflagellates. Trypomastigotes of Trypanosoma sp. were observed in blood smears from three fish (30% prevalence) and some forms were seen to be undergoing division. Using the diagnostic methods of fresh examination and blood centrifugation in hematocrit capillary tubes, the prevalence rate was 80%. This is the first report of Trypanosoma sp. in tuvira in Brazil.

Keywords: Hemoflagellate, hemoprotozoa, live bait.

RESUMO

O objetivo do presente estudo foi reportar a infecção por Trypanosoma sp. em tuviras (Gymnotus aff. inaequilabiatus) oriundas do Pantanal Sul-mato-grossense, Brasil. Dez peixes provenientes do rio Paraguai, Pantanal Sul-mato-grossense, foram avaliados quanto à presença de hemoflagelados. Tripomastigotas de Trypanosoma sp. foram observados nas extensões sanguíneas de três peixes (30% de prevalência), e algumas formas encontravam-se em divisão. Por meio do exame a fresco e da centrifugação do sangue em capilar de hematócrito como métodos para diagnóstico, a taxa de prevalência foi de 80%. Esse é o primeiro relato de Trypanosoma sp. em tuviras no Brasil.

Palavras-chave: Hemoflagelado, hemoprotozoário, isca viva.

Introduction

Trypanosomes are kinetoplastid protozoa that cause blood and is the specific vector of T. catostomi for Catostomus commersoni infection in many species of fish worldwide, including both (JONES; WOO 1992). The main vector of trypanosomiasis in freshwater species (FIGUEROA et al. , 1999; SMIT et al., 2004; fish belonging to the family Loricariidae in Brazil is the leech GU et al., 2007; KONAS et al., 2010) and marine species Batracobdella gemmata (D'AGOSTO; SERRA-FREIRE 1993). (SAUNDERS, 1959; OVERATH et al., 1999; KARLSBAKK, 2004;

The tuvira (Gymnotus aff. inaequilabiatus) (Teleostei: BURRESON, 2007). Transmission of these hemoflagellates between Gymnotidae) is a knifefish native species in the Pantanal basin fish has been attributed to different species of leeches. The leech that inhabits lentic environments, with turbid water and aquatic Hemiclepsis marginata is responsible for transmission of T. carassii vegetation that is rich in organic matter coming from the flooding among European carp (OVERATH et al., 1999). In Canada, process. This species has economic importance because of its Actinobdella inequiannulata is the most abundant leech species use as live bait, driven by the demand for sport fishing in the Pantanal, such as for the dourado (Salminus brasiliensis) and for two catfish species: pintado (Pseudoplatystoma corruscans) and cachara (Pseudoplatystoma reticulatum). However, constant exploitation has caused its numbers to diminish in its natural environment (MORAES; ESPINOSA, 2001). Production in captivity may be an economic alternative for riverbank peoples, and it may diminish the capture pressure on the natural environment. However, lack of information about health issues relating to tuvira has limited their rearing.

The aim of the present study was to report the blood infection by Trypanosoma sp. in tuvira (G. aff . inaequilabiatus) from the Pantanal wetland, Mato Grosso do Sul State, Brazil.

Material and Methods

Tuvira specimens that had been caught by bait gatherers in the Paraguay river (18º 04' 15,00" S and 57º 28' 17,00" W), in the Pantanal, and had been put on the market in the Corumbá city, were acquired and transported to the Fish-farming Laboratory of Embrapa Western Region Agriculture, located in the Dourados, Mato Grosso do Sul State. The fish were kept in round fiberglass tanks with 1000 L of capacity, which were supplied with a continuous flow of water coming from an artesian well (10 L.min^–1).

To diagnose the presence of hemoflagellates, ten fish specimens were subjected to venous puncture of the caudal vein, to collect blood. Blood smears on slides were produced in duplicate and stained panchromatically with the May Grünwald-Giemsa-Wright combination, and were then evaluated under an optical photomicroscope (Nikon^® E200, Japan). Fresh blood between a slide and a coverslip was also examined, by means of phase contrast microscopy (Nikon^® E200, Japan). The same procedure was used for observations after centrifugation of blood samples in hematocrit capillary tubes, just above the white blood cell layer (WOO, 1969).

Results and Discussion

Trypomastigotes of Trypanosoma sp. were observed in the blood smears from three fish (30%) (Figure 1a, b), and some of them were found to be undergoing division (Figure 1d). From evaluating both the fresh samples and the results from centrifugation of blood samples in hematocrit capillary tubes, from the same fish specimens, the prevalence rate was found to be 80% (Figure 1c, d). This characterized the most efficient method for diagnosis.

The prevalence rate of these blood parasites is generally high in fish from the natural environment (OVERATH et al., 1999; SMIT et al., 2004; KONAS et al., 2010). This is possibly related to the immunity mechanisms of the fish against infections. Overath et al. (1999) stated that the immune response of nonmammalian vertebrates is of limited efficacy and/or these parasites evade or manipulate the immune response of their respective hosts.

Multiplication of these hemoflagellates in blood tissue has been described in some vertebrate hosts (PATERSON; WOO, 1984; BURRESON; KARLSBAKK, 2007). This division may be an adaptive mechanism, if the pathogenicity of these trypanosomes for their hosts is dependent on the intensity of the parasitemia (BURRESON; KARLSBAKK, 2007).

Conclusion

This is the first report of Trypanosoma sp. in tuvira in Brazil. Additional studies need to be conducted in order to identify this parasite systematically and molecularly, and to identify its biological cycle, pathogenicity and impact on tuvira populations in the natural environment and on populations reared by bait gatherers.

Acknowledgements

The authors thank Dr. M.A. Rotta for supplying and transporting the fish used in this study and the Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT) for financial support.

Received December 7, 2010

Accepted January 24, 2011

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Publication Dates

• Publication in this collection
  20 Apr 2011
• Date of issue
  Mar 2011

History

• Received
  07 Dec 2010
• Accepted
  24 Jan 2011