Larval cyathostominosis: A retrospective clinical study focused on short‐ and long‐term prognosis

Summary Background Research on the clinical presentation of larval cyathostominosis is sparse; research about long‐term prognosis is even more lacking. Objectives The objective of this study is to evaluate the short‐ and long‐term prognoses of horses with cyathostomin‐related disease and to categorise the spectrum of the presentation of the disease. Study design Retrospective cohort study. Methods An analysis of collected data from horses admitted to an equine clinic between September 2022 and September 2023 with a diagnosis of larval cyathostominosis was performed. Well‐defined inclusion criteria were used and specific data were collected for analysis. Results Twenty‐seven horses were identified with larval cyathostominosis with a median age of 1.5 years (0.9–12 years). Within these 27 horses, 13 horses had acute larval cyathostominosis (ALC), nine horses had chronic larval cyathostominosis (CLC) and five horses presented with colic associated with larval cyathostominosis (COL). Horses in the category colic had a 6.15× higher chance of non‐survival compared to the other two categories. There was no statistically significant difference in survival between ALC and CLC. Associated with non‐survival were the factors colic (hazard ratio of 6.15), absence of diarrhoea (hazard ratio of 0.09) and an increase in haematocrit (hazard ratio of 1.41). The short‐term survival status of COL, ALC and CLC was 1/5, 8/13 and 6/9 horses, respectively. The long‐term prognosis of COL showed partial recovery in one horse, the ALC showed full recovery in 1/6 and partial recovery in 5/6 of the horses and the CLC showed non‐survival in 2/6, partial recovery in 3/6 and full recovery in 1/6 of the horses. Main limitations Retrospective nature of the study, small sample size and financial constraints of the client‐owned patients. Conclusions Disease associated with larval stages of cyathostomins should be considered an important differential diagnosis when dealing with ill‐thrift, weight loss and non‐survival in young horses.