Ireland

Background 

This is the first report of Besnoitia bennetti in donkeys in Ireland. B. bennetti, an apicomplexan protozoan parasite specifc to equids, is an emerging pathogen in Europe. This parasite forms chronic intracytoplasmic cysts in cells of the mesenchymal lineage, mainly fbroblasts, in the skin, sclera and mucosa. Clinical signs in afected equine hosts vary from mild to severe debilitating disease. Little is known of the phylogeny, epidemiology or transmission of B. bennetti infection in donkeys, mules or horses. 

Case presentation 

Two cases of besnoitiosis in donkeys are presented. Both donkeys were born and raised in the south west of Ireland. The first case was a 2.5-year-old donkey that had a suspect sarcoid removed, while the second case, a 2-year-old donkey, had a biopsy of nodular dermatitis of the muzzle. Diagnosis was made by histopathology and the parasite species, B. bennetti, was confirmed by PCR followed by sequencing and microsatellite analysis. Both donkeys had high antibody titres against Besnoitia spp. Small (0.5 mm) scleral, conjunctival and dermal cysts over the muzzle were subsequently observed in both animals. Treatment with trimethoprim sulfadiazine for 30 days did not lead to clinical resolution. The fndings are compared to the cases of besnoitiosis in donkeys reported in the past 10 years throughout Europe. 

Conclusions 

Besnoitiosis should be considered as a differential diagnosis for chronic skin disease particularly in cases of cutaneous masses, non-pruritic dermatitis, and dermatitis that is not responsive to treatment in donkeys and other equids. Future studies are needed to investigate the prevalence of the disease in Irish donkeys, the spread of the disease and the potential impact on the health and welfare of the donkeys.

Data concerning the numbers, locations and types of donkeys being officially registered (passported) in Ireland (32 counties) via horse passport issuing organisations were gathered. The numbers of agricultural area aid scheme (Areas of Natural Constraint (ANC)) applicants registering passported donkeys (as compared with horses) as livestock units (LUs), the numbers of donkeys they registered and the value of payments that thus accrued to the applicants are also reported for each of 26 counties for the years 2012 to 2014 inclusive. Equids have not been eligible for equivalent agricultural schemes in the six counties of Northern Ireland. Horse Sport Ireland registration data shows that two-thirds of almost 8000 donkey passport applicants over a 10-year period came from counties Galway and Mayo and that only one-third of donkeys registered were male. As per ANC figures reported here for 2014, there were over 2500 donkeys registered as LUs on ANC, at a payment value to their keepers (in the 26 counties) of almost €1.6M. Future iterations of the ANC scheme are currently under review with regard to limiting donkey eligibility criteria, for example, to females and neutered males. The future monetary value of (some) donkeys could be adversely affected by restrictions in eligibility and by the uncertainty engendered by the prospect of change with the potential for unintended consequences.

The number of abandoned or otherwise neglected donkeys has significantly increased in Ireland in the recent past. The real or perceived capacity of the donkey to act as a reservoir of equine infectious disease, and thus pose an increased risk of disease transmission to horses and ponies, may be a factor in this increased abandonment and neglect. The authors here report on a field study exploring the infectious disease transmission threat the donkey poses to the general equine industry in Ireland through an examination of biosecurity standards and the views of horse and donkey exhibitors at nine mixed equestrian events in 2014. Quantitative information was gathered via the organising committee (if any) and through an examination of facilities and procedures. Qualitative information was gathered using a semi-structured questionnaire to ascertain the view of exhibitors regarding the keeping of donkeys and any infectious disease transmission risks posed.

Results

At eight of nine events visited there were no entrance controls, no veterinary examinations, no enforcement of legislation regarding equine identification and equine premises registration and no isolation facilities on site for equids. Contact between donkeys and other equids was largely uncontrolled. Exhibitors had travelled from abroad to one event. Exhibitors generally opined that they did not perceive the donkey to represent any additional infectious disease transmission threat above that posed by other equids; there was however a general sense that donkeys were less well regarded for other reasons including nuisance and uselessness.

Conclusions

When biosecurity controls are not in place (or enforced) to actually check passports, verify identification and equine premises registration, mixed equestrian events may unwittingly act as the mechanism of spread of endemic and potentially more seriously exotic equine infectious disease. Donkeys were not generally considered by equine exhibitors at mixed events in Ireland to represent a heightened reservoir of disease or to pose an increased risk of transmission of contagious disease suggesting that other factors should be considered more important when studying the incidence of abandonment and neglect.