Prevalence of endo- and ecto-parasites of equines in Iran: A systematic review

An investigation of the prevalence of equine filariosis in North and Northeast of Iran

Worldwide, equines are affected by equine filariosis, an endemic vector-borne disease caused by heterogenous parasitic nematodes. The main objective of this study was to determine the prevalence of filarial infection among horses in the North and Northeast of Iran. Between October 2021 and July 2022, 145 equine blood samples were investigated, of which 49 cases were from the northeast and 96 were from the north of Iran. Blood samples were taken for microfilariae using Knott's method. Out of 145 blood samples, only 2 cases (1.37%) from northern Iran were positive for microfilaria of Setaria equina, and no positive samples were found from northeast Iran. The first positive sample was a 3-year-old male Iranian horse displaying clinical symptoms of weakness, while the second, an 8-month-old Arabian breed colt, exhibited no clinical signs. According to the results of the current study, the prevalence of equine filariosis is low, contrary to nearby countries. To prevent and control filarial infections among horses and improve their management system, it is therefore important to emphasize filarial infection prevention, control, and management.

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A systematic review and meta-analysis of the prevalence of parasitic infections in equids in Ethiopia

We performed this review to determine the weighted prevalence of equids parasitic infections in Ethiopia. Article searches on parasites of equids were conducted using PubMed, PubMed Central, Google Scholar, Science Direct, Web of Sciences, Scopus, AJOLs and Research Gate. A random effects model was used to estimate the weighted prevalence and to study heterogeneity. The primary searches generated, 3082 potential studies, of which 66 reports met the inclusion criteria and were included in the meta-analysis. There were 32 reports involving two or more equids species, eighteen on donkeys, and sixteen on horses. Moreover, fifty of the reports mentioned helminth infections in equids, thirteen on protozoans, and three on ectoparasites. The estimated weighted prevalence of parasitic infections in equids was 58.3% (95% CI 50.8-65.4%, I2 = 99%). Helminths were the most prevalent parasites in equids, accounting for 77.1% (95% CI 71.4%, 82%, I2 = 98.5%), followed by ectoparasites at 35.4% (95% CI 33.4-37.52%, I2 = 88.2%) and haemoparasites (protozoans) at 10.84% (95% CI 6.6%, 17.3%, I2 = 98.1%). Furthermore, with a prevalence of 82.3% (95% CI 75.9-87.3%, I2 = 97.4%), donkeys were the most affected equids with helminth parasites. From the reports, we found forty-three species of helminth parasites affecting equids, including thirty-four nematode species (Strongylus, Cyathostomum, Coronocyclus, Cylicocyclus, Cylicostephanus, Trichostrongylus, Oesophagodontus, Strongyloides, Triodontophorus, Gyalocephalus, Poteriostomum, Dictyocaulus, Oxyuris, Habronema, Draschia, Parascaris, Setaria, and Probstmayria species), three trematodes (two Fasciola and one Gastrodiscus species), three cestodes (two Anoplocephala and one Anoplocephaloides species) and three botfly larvae (one Rhinoestrus and two Gasterophilus species). Trypanosoma species (T. congolense, T. vivax, T. brucei, T. equiperdum, and T. evansi), piroplasms (Theileria equi and Babesia caballi), and Eimeria species have also been reported to affect equids. Ticks (Amblyomma variegatum, A. gemma, Rhipicephalus decoloratus, R. evertisi evertisi, R. pulchellus, R. muhsame, R. sanguineus, Hyalomma rufipes, and Hy. truncatum) and lice (Bovicola equi and Haematopinus asini) were the ectoparasites recorded to affect equids. The risk of publication bias across studies was likely to be high due to differences in publication year and diagnostic techniques. In conclusion, parasitic infections of equids are common in Ethiopia and are caused by a variety of parasite species, putting the performance and well-being of these packing animals at risk. Therefore, more research is needed to identify infection risk factors and raise awareness of the consequences of parasitism in order to provide strategies to mitigate the problems in equids.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-023-01598-3.

Emergent and Neglected Equine Filariosis in Egypt: Species Diversity and Host Immune Response

Equine filariosis (EF) is a neglected vector-borne disease caused by nematode species belonging to the Onchocercidae and Setariidae families. Aside from their zoonotic potential, some species are responsible for serious health problems in equids worldwide, leading to significant economic difficulties. Here, we molecularly investigated equine blood samples (320 horses and 109 donkeys from Egypt) and four adult worms isolated from the peritoneal cavity of 5 out of the 94 slaughtered donkeys. In addition, quantitative enzyme-linked immunoassays (ELISAs) targeting circulating cytokines were used to identify whether the immunological profile of the infected animals is a Th1 (i.e., INF-gamma as indicator) or Th2 (i.e., IL-5 and IL-10 as indicators) response type. Overall, 13.8% and 0.3% of the donkeys and horses, respectively, were scored as positive for filaroid DNA. The 18S phylogeny revealed the occurrence of three different filaroid species, identified here as Mansonella (Tetrapetalonema) sp., Setaria digitata and Dirofilaria repens. Th1 (INF-gamma and IL-5) and Th2 (IL-10) immune response types were identified in equines infected with S. digitata and Mansonella (T.) sp., respectively. These results provide new data on the species diversity of EF in Egypt and extend knowledge of the downregulation of the protective immune response by the potentially zoonotic Mansonella (T) sp. There is an urgent need to implement control measures to preserve equine health and limit the propagation of these vector-borne filaroids in Egypt.

Prevalence of endo- and ecto-parasites of equines in Iran: A systematic review

Equines are subject to infection with many parasites, which threaten their health. In the present study, we systematically reviewed existing literature on the prevalence of endo- and ectoparasites of equines in Iran. Major electronic databases, including PubMed, PubMed Central, Google Scholar, Science Direct and Scientific Information Database (SID), were searched (Last updated 11/05/2018) for relevant literature of parasites that have been identified from equines in Iran. Of the 1809 titles produced by bibliographic search, 38 were included in the review. Twenty-seven of the studies were on horses, six on donkeys, three on both horses and donkeys, and one study was on both horses and mules. Furthermore, 24 of the studies reported infections caused by protozoa, thirteen by helminths, two by ectoparasites, and one by both protozoa and helminths. The overall pooled prevalence of parasitic infection was 28.8% (95%CI: 22.9-35.7, I²  = 93.4%). Helminths were the most prevalent parasites 46.7% (95% CI: 24.1-70.7, I²  = 96.0%). Furthermore, donkeys were the most affected equine, with a prevalence of 70.7% (95% CI: 53.2-83.7, I²  = 92.5%). The protozoa frequently reported included nine species belonging to the genera: Neospora, Toxoplasma, Theileria, Babesia and Eimeria. Also, the helminths frequently reported included 21 species belonging to the genera: Strongylus, Dicrocoelium, Oxyuris, Habronema, Echinococcus, Dictyocaulus, Cyathostomum, Probstmayria, Anoplocephala, Setaria and Fasciola. Ticks were the only ectoparasites frequently reported. Parasitic fly species of the genera Gasterophilus were also reported. The study-level risk of bias was likely to be high because of differences in study design. Parasitic infections of equines in Iran are frequent and caused by a diversity of parasites, which threatens the health and well-being of these animals. Further research is needed in the area to identify the risk factors of infection for effective control of the parasites.