versão On-line ISSN 0717-7712
Parasitol. latinoam. v.62 n.1-2 Santiago jun. 2007
Parasitol Latinoam 62: 76 - 78, 2007 FLAP
Eimeriosis in capybaras (Hydrochaeris hydrochaeris) in the state of Rio Grande do Sul, Brazil
ANA CLAUDIA FAGUNDES GURGEL*, AMANDA DOS SANTOS SARTORI** and FLÁVIO ANTONIO PACHECO DE ARAÚJO***
* Master Student at PPGCV. Faculdade de Medicina Veterinaria. Universidade Federal do Rio Grande do Sul. Av.Benito Goncalves, 9090. CEP 91540-000, Porto Alegre, RS, Brasil.
Capybaras are the largest of living rodents and are the most common wild rodent in the state of Rio Grande do Sul, Brazil. They are commercially bred for their meat, hide, and oil. The present study aims to shed some light upon intestinal protozoa of capybaras using Sheather's method modified by Benbrook to analyze 250 fecal samples. The following Eimeria species were detectedOOO in 52.4% of the fecal samples: E. trinidadensis, E. ichiloensis, E. boliviensis, in addition to another species that could not be identified. With regard to the total oocyst count, the relative frequency of different Eimeria species was as follows: E. trinidadensis (55%), E. ichiloensis (32.6%), E. boliviensis (4.8%), and an unidentified Eimeria species (7.6%). The unidentified species was called Eimeria araside sp.n. (Apicomplexa: Eimeriidae).
Key words: capybara, Eimeria, faeces.
Capybaras are relatively frequent in several regions of the state of Rio Grande do Sul, Brazil, and along with coypus (Myocastor coypus), according to a recent study carried out with six families of wild rodents, were considered to be the most abundant type of rodent in the state of Rio Grande do Sul1.
The experience of more industrialized countries in the rearing and exploitation of capybaras has shown that their hide is widely used for the manufacture of gloves, shoes, belts, etc2, with a great potential for the production of meat and oil3.
Eimeriosis is a contagious catarrhal enteritis that affects the small and/or large intestine and is caused by different Eimeria species4. It usually occurs among young animals, whereas successive infections in adult animals make their body develop a resistant immune system, turning them into carriers of the disease5.
Unsporulated oocysts consisting of a nucleated protoplasmic mass wrapped by a resistant wall are passed in the feces. Under appropriate oxygen conditions, high humidity and ideal temperatures (of approximately 27 °C) and within two to four days, oocysts sporulate and become infective6.
The clinical diagnosis of eimeriosis is established by the following signs: sudden onset of bloody diarrhea, accompanied by dehydration, weight loss, loss of appetite, lethargy, and sometimes, death. The laboratory diagnosis is made by coproparasitological analysis, with Sheather's method being the most widely used technique, and also by necropsy, which takes macroscopic and microscopic lesions into consideration7.
According to Carini8, two new Eimeria species have been found in capybaras: E. capibarae and E. hydrochoeri.
MATERIAL AND METHODS
The capybaras were from the zoo in Sapucaia do Sul, from a privately-owned rearing station in Santo Antonio da Patrulha and from an experimental center (CEULBRA - Centro Experimental da Universidade Luterana do Brasil), located in the town of Montenegro. In these places, animals of different ages lived together. A total of 250 fecal samples were collected from the rearing stations. The samples were collected at an interval of approximately 30 days. Freshly shed feces were collected from trie ground, placed in plastic vessels, kept on ice and taken to the Laboratory of Protozoology at FAVET-UFRGS. At the laboratory, the samples were kept in a refrigerator at approximately 8° C, for later processing.
The samples were collected between February and August 2004 and the study was completed in March 2005.
The fecal samples were submitted to Sheather's method modified by Benbrook, based on the study by Hoffmann9, used to detect Eimeria spp. After the detection of Eimeria oocysts through this method, they were submitted
to ocular micrometry. The aim of this method was to measure the length and width of oocysts and then to identify them. These data, coupled with morphological characteristics, allowed classifying the species found in the experiment. Afterwards, the unsporulated oocysts were protographed at xlOO and x400 magnification and sporulated in 2.5% potassium dichromate. Sporulation occurred on the 25th day and the sporulated oocysts were photographed again at xlOO and x400 magnification.
RESULTS AND DISCUSSION
The genus Eimeria was detected in 52.4% of fecal samples of the analyzed capybaras, and four species were found: E. trinidadensis (55%), E. ichiloensis (32.6%), E. boliviensis (4.8%) and E. araside (7.6%).
Table 1 shows the occurrence (%) and the micrometric parameters of oocysts (mean ± standard deviation) of different Eimeria species found in capybaras, in Santo Antonio da Patrulha, Montenegro and Sapucaia do Sul, state of Rio Grande do Sul, Brazil.
The oocysts classified as E. araside had the following morphological characteristics: ellipsoidal oocyst of uniform thickness consisting of two layers: a very smooth and well-delineated, dark brown outer layer, and a homogeneous inner layer. No micropyle, micropylar cap and oocyst residuum were observed (Figure 1).
Moreno et al10, carried out a study about gastrointestinal parasitism of capybaras in Venezuela, where 41.7% of 84 fecal samples were positive for Eimeria spp, yielding similar results to the present study (52.4%).
Authors reported three new Eimeria species in capybaras in Bolivia and Venezuela: E. trinidadensis, E. ichiloensis andii. boliviensis11. They found an occurrence of 76% and 37% for E. trinidadensis in Bolivian and Venezuelan capybaras, respectively11. The same authors found an occurrence of 86% and 84% for i1, ichiloensis in Bolivian and Venezuelan capybaras, respectively, which differs from the results obtained in the present study (32.6%). In Venezuela, they found an occurrence of 26% of E. boliviensis in Bolivian capybaras and of 26% in Venezuelan capybaras, which differs from the results herein (4.8%)n.
According to Casas et al11, E. trinidadensis resembled E. hydrochoeri, found in some Brazilian animals, as they had the same size, despite different morphological characteristics8. According to these authors, E. ichiloensis resembled E. capibarae, found by Carini8 in some Brazilian capybaras, since they had the same morphological characteristics, but were of different sizes.
The present study revealed an oocyst type that belongs to an Eimeria species not yet described in the literature, which was therefore first described in the present study.
The new species, E. araside sp.n. (Apicom-plexa: Eimeriidae), was named after the three researchers who first described this type of Eimeria12.
The lack of similar studies in the literature does not allow for a more in-depth analysis. However, the present study is a starting point for future studies on protozoa in the feces of capybaras.
Our conclusion is that capybaras are susceptible to Eimeria spp., with three species being identified: E. trinidadensis, E. ichiloensis and E. boliviensis. One of the species was not identified because its size did not match any species portrayed in the literature, so a new species called E. araside sp.n. (Apicomplexa: Eimeriidae) was described.
1.- SILVA F. Mamíferos silvestres - Rio Grande do Sul. 2. ed. Porto Alegre: Fundacáo Zoobotánica do Rio Grande do Sul 1994; 7: 246. [ Links ]
2.- SILVA L F. Criacao de capivaras em cativeiro. Sao Paulo: Nobel 1986; Cap. 14, p. 62-5. [ Links ]
3.- SILVA NETO, P.B. Criacao racional e comercial de animáis silvestres. J. SOS Mata Atlántica, Sao Paulo, 1995; 7, n. 2, p. 3. [ Links ]
4.- SILVA N R S, CHAPLIN E L, KESSLER R H. Protozooses dos animáis domésticos. Porto Alegre: UFRGS, 1980; 220p. [ Links ]
5.- CARDOSO S B. Protozoologia veterinaria. Fortaleza: IOCE, 1986; 181 p. [ Links ]
6.- URGUHART G M, ARMOUR J, DUNCAN J L, et al. Parasitologia veterinaria. 2a ed. Rio de Janeiro: Guanabara Koogan, 1998; 273 p. [ Links ]
7.- FORTES E. Parasitologia veterinaria. 4. ed., ver. ampl. Sao Paulo: ícone 2004; 607 p. [ Links ]
8.- CARINI A. Sur Deux Nouvelles Eimeria D' Hydrochoerus Capibara. Ann Parasitologie 1937; 15: 367-9. [ Links ]
9.- HOFFMANN R P. Diagnóstico de parasitismo veterinario. Porto Alegre: Sulina, 1987; 156 p. [ Links ]
10.- MORENO L G, LORD R, MORALES G, et al. Parasitismo gastrointestinal de Hydrochaeris hydrochaeris en un hato del Estado Apure- Venezuela. Vet Trop 1999; 24: 85-91. [ Links ]
11.- CASAS M C, DUSZYNSKID W, ZALLES L M. Three new Eimerians in capybara (Hydrochaeris hydrochaeris) populations from Eastern Bolivia and Southern Venezuela. J Parasitol 1995; 81: 247-51. [ Links ]
12.- ARAUJO F A P, SILVA N R S, DENICOL A C. Identificacao de protozoários parásitos intestinais de capivaras. In: SALÁO DE INICIACÁO CIENTÍFICA, 2001, Porto Alegre, RS. Anais do XIII Salao de Iniciacáo Científica da Universidade Federal do Rio Grande do Sul, 22 a 24 de outubro 2001, ESEF- Campus Olímpico. Porto Alegre: Universidade Federal do Rio Grande do Sul, 2001. Sessáo 4 (Biodiversidade e Ecologia Animal) em Ciencias Biológicas, trabalho 029. p. 252. [ Links ]