Pituitary Pars Intermedia Dysfunction (PPID), may be more susceptible to worm infections.
Horses with PPID often have a weakened immune system, which can allow worms, such as cyathostomes, to thrive more easily compared to healthy horses. These horses may also not respond as effectively to standard deworming treatments due to their altered immune function.
A study conducted in Australia aimed to determine whether horses with PPID had increased strongyle faecal egg counts (FEC) compared with control horses.
The study, led by Adelaina Horner, took place over a fourteen-week period and involved adult horses and ponies over eight years old in Victoria, Australia. All horses lived on pasture and had not been dewormed for at least three months prior to the study. A total of 45 privately owned horses and ponies met the criteria for inclusion, with 14 horses diagnosed with PPID and 31 serving as controls. PPID diagnosis was confirmed by elevated plasma ACTH concentrations (above 120 pg/mL) along with at least one clinical sign of the disorder.
All horses were dewormed with a standard dose of a commercially available ivermectin product. Faecal egg counts were taken before treatment and then every two weeks for 14 weeks. A FEC of 200 eggs per gram (EPG) or higher was used as the cutoff for significant worm burden.
The results showed that the egg reappearance period (ERP) after deworming was shorter in PPID horses, and cumulative FEC after deworming was higher in these horses. However, the researchers noted that some PPID horses consistently had no detectable eggs or low EPG (≤ 200) throughout the study, and this could not be explained by observed husbandry practices.
Worm eggs collected during the study were cultured in the laboratory, and examination of the larvae confirmed that all worms were cyathostomin species.
The researchers advise monitoring egg shedding before anthelmintic treatment in PPID horses, in line with sustainable worm management guidelines, as some PPID horses consistently showed low FEC results.
While hormonal disorders like PPID do not directly cause an increase in parasitic infections, they can impair the horse’s immune system and overall health, making them more vulnerable to worm infections and potentially reducing the effectiveness of treatments. Effective management of both the hormonal disorder and parasitic infections is crucial for maintaining the health of affected horses.
For more details, see:
Strongyle egg shedding and egg reappearance periods in horses with pituitary pars intermedia dysfunction
Adelaina Horner, Nicholas J. Bamford, Michael J. Stear, David Piedrafita, Abdul Jabbar, Kristopher J. Hughes, Charles M. El-Hage, Sarah Preston
Veterinary Parasitology (2024) Vol 328, 110176
No comments:
Post a Comment