Larval cyathostomiasis.

The research reveals that cyathostomiasis, a parasitic infection in horses due to the release of large numbers of small strongyles larvae from the intestine, is increasingly becoming a clinical problem. Currently, the drugs moxidectin and fenbendazole are effective against the parasite stages, though drug resistance may increase the prevalence of the disease.

Overview of Cyathostomiasis in Horses

• The study focuses on cyathostomiasis, a condition in horses resulting from the sudden release of large numbers of the larval stages of small strongyles from the mucosa of the large intestine.
• Previously more common in Europe, the condition is now acknowledged as a growing clinical problem in US horses.
• The disease manifests through noticeable clinical signs such as diarrhea, abdominal edema, fever, colic, weight loss, and poor body condition. Hypoalbuminemia and the presence of large numbers of small strongyles found in the horses’ feces are also characteristic features of the disease.

Disease Occurrence and Treatment

• The disease often seems to occur seasonally, particularly in late winter and early spring, or after drug treatment to remove the luminal stages of small strongyles.
• Two commercial drugs, moxidectin and fenbendazole, have been found to be effective against the encysted larval stages of these parasites.

Drug Resistance as a Limiting Factor

• One of the significant challenges outlined in this study is drug resistance in small strongyles. This resistance applies to all currently available antiparasitic compounds, with the exception of macrocyclic lactones, which include ivermectin and moxidectin.
• Drug resistance presents a limiting factor in controlling these parasites and may result in increased prevalence of clinical cyathostomiasis over time.