Introduction

The donkeys (Equus africanus asinus), like the rest of the animal species are susceptible to the infestation by ecto and endoparasites, the investigations with respect to the parasitism that affect this species are very scarce and it is assumed that the signs, pathogeny, treatment and control are very similar to those observed in horses (^{Svendsen et al., 1997}).

Among the endoparasites that can affect the donkeys are the gastrointestinal helminths, pulmonary worms and flatworms or fasciolas, being the gastrointestinal helminths, the most frequent; which cause different clinical manifestations ranging from diarrhea to anemia and even death. The severity of the signology will depend on the age, nutritional status and resistance of the donkey, as well as on the parasite involved and the degree of infestation (^{Svendsen et al., 1997}, ^{Matthews J. B, 2014}).

The gastrointestinal helminths that most frequently affect donkeys are ascarids (Parascaris equorum), large nematodes (Strongylus spp), small nematodes (Thrichonema spp), pinworm (Oxyuris equi) and the roundworms (Strongyloides), with nematodes being the most difficult to treat because of the degree of resistance to anthelmintics (^{Svendsen et al., 1997}, ^{Matthews, 2014}).

The diagnosis of gastrointestinal parasitic diseases caused by different types of gastrointestinal nematodes is performed by means of coproparasitoscopic examinations, which consists in observing the presence and morphology of larvae and eggs, as well as the quantification of the latter to determine the parasitic load. Depending on the parasitic load species, it is possible to determine if it is pertinent or not to perform a deworming, the presence of 50 to 450 eggs per gram of feces (HGH) is considered a low burden and therefore no pharmacological treatment is required. However, the presence of more than 1000 HGH is considered a high burden, which will require the implementation of a deworming program (^{Svendsen et al., 1997}).

In addition to coproparasitoscopic analysis it is important to consider that in order to have a correct diagnosis regarding parasitosis it is necessary to combine them with clinical signs (weight loss, lethargy, depression, diarrhea, severe cases of colic and fever) and complementary tests such as hemogram and blood biochemistry (^{Svendsen et al., 1997}, ^{Cribb et al., 2006}). Therefore the objective of the present investigation was to identify the main species of gastrointestinal parasites in donkeys of the Valley of Tulancingo

Material and Methods

Results and Discussion

The donkeys of the Tulancingo Valley presented a 100% (11/11) prevalence of gastrointestinal parasites, a result similar to that published by ^{Bedoya et al. In 2011} who determined a 92% prevalence of gastrointestinal parasites on horses (^{Bedoya et al., 2011}). On the other hand, ^{Francisco and collaborators in 2009} mention that the parasitic infections of greater prevalence are those caused by gastrointestinal helminths, especially strongyloides and, to a lesser extent, ascarids and pinworm.

In the present investigation, 91% (10/11) of the animals studied presented release of Trichostrongylus spp eggs, 64% (7/11) presented Strongylus spp, 36% (4/11) Trichonema spp, 27% (3/11) Parascaris equorum, Strongyloide westeri, 9% (1/11) Anaplocephala spp and Oxyuris equi as seen in Figure 1 and Table 1.

Figure 1 Frequency of gastrointestinal parasites in donkeys in the Tulancingo Valley 

In Figure 1 it can be observed that the predominant nematode in the sampling was Trichostrongylus spp with 91% followed by Strongylus spp with 64%, which are associated with ulcerative gastric disorders, results that agree with ^{Matthews and collaborators in 2013} who propose that the Strongyloides spp are the most important parasites in donkeys in the United Kingdom (^{Matthews et al., 2013}). ^{Cardona and colleagues in 2015} determined that 56.9% of the donkeys under evaluation had gastric ulcers associated with Trichostrongylus axei (^{Cardona et al., 2015}).

^{Bedoya and collaborators in 2011} determined a 92% prevalence of Trichostrongylus spp in horses (^{Bedoya et al., 2011}).

In the present experiment, eggs of Strongylus spp, Trichostrongylus spp., Strongyloides westeri, Parascaris equorum, Oxyuris equi, Trichonema spp., and Anaplocephala spp. were observed. These results coincide with those reported by ^{Felipelli et al. (2015)} and (^{Güiris et al. (2010)}, who observed in horses the presence of Parascasis equorum, Strongyloides westeri, Strongylus edentatus, Oxyuris equi, Strongylus vulgaris and additionally Triodontophorus serratus, Cyathostominae, Habronema muscae, Trichostrongylus axei (^{Güiris et al., 2010}, ^{Felipelli et al., 2015}).

Conclusion

Trichostrongylus spp is the predominant gastrointestinal parasite in donkeys in the Tulancingo Valley. With the results of the present investigation the main parasitosis in donkeys of the Tulancingo Valley has been identified, information that will allow proposing specific treatments for each case this will impact positively on the welfare of the species under study.