versión impresa ISSN 0716-0720
Parasitol. día v.23 n.1-2 Santiago ene. 1999
PREVALENCE OF Trichomonas gallinae FROM
THE UPPER DIGESTIVE TRACT OF THE COMMON
PIGEON, Columba livia IN THE SOUTHERN BRAZILIAN
STATE, RIO GRANDE DO SUL
Tiana Tasca*and Geraldo A De Carli**+
*Instituto d e Biociências, Curso de Pós-Graduação em Biociências-Zoologia, Pontifícia Universidade Católica do Rio Grande do Sul (IBC-PUCRS), Av. Ipiranga, 6681, Porto Alegre 90619-900 RS, Brazil
**Departamento de Análises Clínicas, Faculdade de Farmácia, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Av. Ipiranga, 6681, Porto Alegre 90619-900 RS, Brazil. E-mail: firstname.lastname@example.org - + Corresponding author.
Trichomonas gallinae (Rivolta, 1878) is a parasitic protozoan of the upper digestive tract and various organs of different avian groups, being common among the Columbids, was isolated described and its prevalence studies in the Southern Brazilian State, Rio Grande do Sul. The morphology study of the live specimens done by examination of fresh and stained specimens, showed that the T. gallinae isolated has the same morphological characteristics as the upper digestive tract trichomonads previously described by other authors.
Key-words: Trichomonas gallinae, Columba livia, columbiformes, domestic pigeon, isolation, upper digestive tract, in vitro cultivation
Trichomonas gallinae (Rivolta) occurs in the upper digestive tract and various organs of different avian groups, but it is particularly common in Columbiformes (doves and pigeons). The domestic pigeon, Columba livia, is the primary host of this flagellate. Other columbiform hosts have been found to harbor it, as have also galliform birds (especially turkeys), Java sparrows, various raptors, and sea gulls. The organism cause serious losses among these birds1. The morphology of the flagellate has been described by several investigators; however, the most significant contributions to the understanding of its structure were made by Stabler,2-4 and by Abraham and Honigberg.5 The purpose of this study was to determine the prevalence of T. gallinae in domestic pigeons in the Southern Brazilian State, Rio Grande do Sul.
MATERIAL AND METHODS
In the present study the observations were made on the samples collected from the upper digestive tract of domestic pigeons, C. livia. The throats of pigeons were swabbed and the swabbings inoculated into trypticase-yeast extract-maltose (TYM) medium,6 for incubation. Samples were cultured axenically in vitro, without antibiotics,4 in a TYM medium without agar, pH 7.2, supplemented with 10% (v/v) heat inactivated horse serum, in air, at a temperature of 37°C (± 0.5). Some cultures were established without the use of antibiotics, others were isolated with 5,000 units of penicillin and 1,000 mg of dihydrostreptomycin per ml of the original culture. In no instance were antibiotics used in the subsequent serial transfers. Certain samples of the original isolations were frozen and maintained at -196°C with 5% (v/v) of dimethyl sulfoxide (DMSO) as previously described.7 Material for the stained smears was obtained from parasites harvested (250 x g for 20 min) from a 24 hr culture in TYM medium, and stained by the Giemsa method.
RESULTS AND DISCUSSION
Prevalence: T. gallinae was found in 18 of 68 cultures of throats swabbed, representing a prevalence of 26.47% in pigeons. The present work is apparently the second report of the occurrence of a trichomonads in the upper digestive tract of pigeons in the Southern Brazilian State, Rio Grande do Sul. In other paper, the authors8 reported that 62.3% of 167 cultures of throats swabbed of pigeons from different areas of Southern Rio Grande do Sul, Brazil, harbored trichomonads in the upper digestive tract.
Light Microscopy: Direct microscopic examination of wet smears from the throats (mouth and the oropharyngeal area) revealed vast numbers of actively motile flagellate protozoa. These were classified as trichomonads because of their elongate ellipsoid shape, the presence of an obvious undulating membrane associated with four free anterior flagella which could be accurately counted only when the trichomonads had slowed down or stopped moving. The body is very plastic, but not particularly ameboid. Most of these morphological features could be recognized in-air-dried smears of throats swabbed , fixed in methanol and stained with Giemsa.
Cultivation: Examination of the cultures after incubation at 37°C for 48 to 72 hr revealed a heavy growth of flagellates. Trichomonads in the logarithmic phase of growth, and subcultured every 48 hr exhibited more than 95% of mobility and a normal morphology. The cultures were routinely maintained in TYM medium at 37°C and transferred three times per week (every 48 to 72 hr).
Morphology: The measurement of our material were compared with those results of others3,5,8,9 with the intent to identify possible variation. In the present investigation, it was observed that the T. gallinae found in the mouth and the oropharyngeal area of pigeons has the same morphological characteristics as those in the upper digestive tract of pigeons previously described by other authors.
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