From the Guidelines
People on horse farms are most likely to acquire parasitic infections from zoonotic parasites, primarily equine roundworms, pinworms, and strongyles, with Strongyloides westeri being of particular concern due to its ability to penetrate human skin and cause cutaneous larva migrans. The most recent and highest quality study on this topic is from 2011 1, which highlights the risks associated with ecto- and endoparasites when humans and exhibit animals interact. Some key points to consider include:
- Ectoparasites such as Sarcoptes scabiei, a skin mite that infests humans and animals, can cause skin irritation and itching 1
- Animal fleas can carry a tapeworm species that can infect children who swallow the flea 1
- Animal parasites can infect humans who ingest soil or other materials contaminated with animal feces or who come into contact with contaminated soil 1
- Parasite control through veterinary care and proper husbandry combined with hand washing reduces the risks associated with ecto- and endoparasites 1 Prevention is crucial and includes:
- Wearing gloves when handling manure
- Washing hands thoroughly after farm work
- Wearing closed footwear
- Avoiding eating in barn areas
- Maintaining good farm hygiene practices like regular manure removal These parasites typically spread through the fecal-oral route when microscopic eggs or cysts are accidentally ingested after handling contaminated materials, making proper hygiene essential for anyone working around horses. If infection occurs, treatment typically involves antiparasitic medications like albendazole, ivermectin, or mebendazole, depending on the specific parasite identified 1.
From the Research
Parasites Found on Equine Farms
The following parasites have been found to infect horses on equine farms:
- Cyathostominae, which was the most common parasite found in horses from individual and agrotouristic farms 2
- Strongylus spp., which was found in some individuals from equine farms 2, 3, 4
- Parascaris equorum, which was found in horses from individual and agrotouristic farms 2, 3
- Strongyloides westeri, which was found in some individuals from equine farms 2
- Anoplocephala, which was found in horses from individual and agrotouristic farms 2, 3
- Oxyuris equi, which was found in working horses 3
- Fasciola spp., which was found in working horses 3
- Eimeria leuckarti, which was found in working horses 3
- Theileria equi and Babesia caballi, which cause equine piroplasmosis 5
Risk Factors for Infection
Several risk factors have been identified for infection with these parasites, including:
- Type of farm, with individual farms having a higher infection rate than agrotouristic farms 2
- Housing, feeding, and pasture-care practices 2
- Access to pasture, which increases the risk of egg shedding and seropositivity for Strongylus vulgaris 4
- Age, with younger horses being more likely to shed eggs and be seropositive for Strongylus vulgaris 4
- Time since last treatment, which increases the risk of strongyle egg shedding 4
- Type of anthelmintic treatment used, with moxidectin and ivermectin decreasing the risk of strongyle egg shedding 4