Toxocara cati ( Schrank , 1788 ) ( Nematoda , Ascarididae ) in different wild feline species in Brazil : new host records

This is the first detailed description of Toxocara cati parasitizing felines in South America. Seventeen run over wild felines (Leopardus colocolo, Leopardus geoffroyi, Leopardus tigrinus, and Puma yagouaroundi) were collected from different towns in the State of Rio Grande do Sul, Brazil. The morphometry of males and females allowed the identification of specimens as being T. cati. The helminths were found in the stomach and intestine of hosts with prevalences of 66.6% in L. colocolo, L. geoffroyi, and L. tigrinus; and 60% in P. yagouaroundi. The ecological parameters were calculated for each host and L. colocolo had the highest infection intensity (22.5 helminths/host). This is the first report of T. cati parasitizing four wild felines species in southern Brazil, besides a new record of this parasite for two host species.

The genus Toxocara was proposed by Stiles in 1905, with the type species Lumbricus canis Werner, 1782 (= Toxocara canis Werner, 1782) (SPRENT, 1956).A wide species review of the genera Toxocara and Neoascaris was conducted by Warren (1971).In this study, the author extended the diagnosis of the genus Toxocara and made new combinations, eliminating the genus Neoascaris and transferring all species of Neoascaris to the genus Toxocara.
Currently, 23 species are known to belong to the genus Toxocara (GIBBONS et al., 2001).Among them, the species Toxocara cati (Schrank, 1788) Sprent, 1956 is a parasite of carnivores from different geographic areas in the world.According to Sprent (1982), the species was introduced to the Neotropical Region by domestic animals brought by Europeans.Sprent (1956) studied the taxonomy and development of T. cati, but morphometric data on the species has not been sufficiently developed, yet.
All measurements were expressed in micrometers (μm), unless otherwise indicated.Mean, standard deviation and number of specimens measured for a determined character appear in parentheses.The ecological terms were used according to Bush et al. (1997).Drawings were made using a microscope with a drawing tube.The carcasses were deposited in the "Coleção de Vertebrados" do "Museu de Ciências Naturais da Ulbra" (MCNU) Toxocara cati in different wild feline species in Brazil Canoas, Rio Grande do Sul, Brazil, and the helminths were deposited in the "Coleção Helmintológica do Instituto Oswaldo Cruz" (CHIOC) Rio de Janeiro, Brazil, and in the "deposited in the "Coleção Helmintológica do Museu de Ciências Naturais da ULBRA (CHMU)".The parasite systematic used in this study was proposed by Hartwich (2009).Host species' names followed the nomenclature proposed by Wozencraft (2005).

Toxocara cati (Schrank, 1788) Sprent, 1956
Description based on 25 specimens cleared with lactophenol, all measured.Ascarididae, Toxocarinae.Body with the anterior region dorsally curved and the cuticle transversely striated (Figure 1).Strias range from 7.08 to 36.88 (16.94; 6.98; n = 25) long.The buccal capsule had three lips (Figures 1 and 2): one dorsal, with two large papillae situated on the sides (Figure 2) and two subventral lips, both with a single large papilla, in the middle of the lip and another small papilla close to the amphidial pore (Figure 2).In the margin of each lip, there are several denticles ranging from 112 to 136 (124; 7.8; n = 8) (Figure 2), with a large shape on the botton which progressively change to a triangular shape on the top of the lip.Interlabia absent.A pair of cervical alae, slightly striated (Figure 1), representing 11.5% of total body length (TBL).Nerve ring localized near the excretory pore, of difficult visualization (Figure 1).The esophagus is simple, opening to the intestine with a posterior bulb (Figure 3).

Discussion
The nematodes found in four wild feline species were identified as T. cati due to the presence of cervical alae, esophagus with a bulb at the posterior end, males with a terminal appendage and, females with a vulva in the body's anterior third.
Our measurements of T. cati were similar to those presented by Warren (1971), Vicente et al. (1997), Beldomenico et al. (2005), Radwan et al. (2009), Esfandiari et al. (2010) and Gallas and Silveira (2011).Males and females' width was smaller than that obtained by Warren (1971).The esophagus length was within the range obtained by Radwan et al. (2009).The measurements of the present work are higher than those given by Esfandiari et al. (2010).Gallas and Silveira (2011) found a positive correlation for all associations of the analyzed characters of T. cati.The authors suggest that cervical alae, esophagus length, and spicules in males, and distance of vulva from anterior end in females could be characters enabling strategies of this species in different environments.
According to Baruš et al. (1979) the average number of the denticles per lip of T. cati was 126, ranging from 115 to 129.In this study, the average number of the denticles was 124, ranging from 112 to 136.This character, according to the authors, could be used to differ T. cati from other species of Ascarididae.Vicente et al. (1997) presented morphometric data of T. cati based on measurements by Stiles.Vieira et al. (2008) did not present morphometric data and ecologic parameters of infections, limiting their work to the record of species deposited in the "Coleção Helmintológica do Instituto Oswaldo Cruz" (CHIOC).The present study provides, for the first time, morphometric data and ecological parameters of T. cati in wild felines from Brazil.
The ecological parameters differed between the data found in the literature (Table 1) and that of this study.Beldomenico et al. (2005) found in Argentina a higher prevalence than that observed in the present study, taking into account the similar sample size.However, Fiorello et al. (2006), in Bolivia, reported a smaller prevalence.In studies carried out with T. cati from North America, the feline species examined through a high sample size were Felis canadensis (= Lynx canadensis Kerr, 1792) (n = 274; 22%), Felis rufus (= Lynx rufus Schreber, 1777) (n = 143; 89%), and Felis (Lynx) canadensis (= Ly. canadensis) (n = 113, 4%) (Table 1).Among these, the highest intensity of infection was reported for F. rufus (= Ly. rufus) (44) by Watson et al. (1981).
The mean intensity of infection for L. colocolo (22.5) was higher with regard to the other examined hosts.According to Sunquist and Sunquist (2002), the ecology of this species is insufficiently known, however, the host presents a generalist diet, eating any small vertebrate, a characteristic that may be associated to the high number of nematodes found when compared to other hosts.The differences found may be associated to the life cycle of the helminth and the availability of hosts infected with T. cati larva in the different environments.
In the life cycle of different species of the genus Toxocara the definitive host may be infected in two ways: through the ingestion of paratenic hosts (invertebrates and vertebrates) or during the prenatal period, through transmammary transmission, constituting an important pathway (ANDERSON, 2000).The analysis of infected hosts from different geographic areas in the State of Rio Grande do Sul allows one to conclude that the helminth's life cycle is occurring in whole State.This helminth species is reported for the first time for L. colocolo and L. tigrinus; it's the first report for L. geoffroyi in Brazil, as well as for P. yagouaroundi in the State ofRio Grande do Sul.
This is the first report of T. cati in wild felines of the species Leopardus colocolo Molina, 1782 and Leopardus tigrinus Schreber, 1775, as new hosts in South America.The feline species Leopardus geoffroyi d'Orbigny & Gervais, 1844, is reported as a new host in Brazil and P. yagouaroundi É. Geoffory Saint-Hilaire, 1803, as a new host in the State of Rio Grande do Sul, Brazil.

TABLE 1 :
Comparison of T. cati ecological parameters in different hosts.