Besnoitia bennetti in donkeys an emerging disease in the US and UK

Besnoitia bennetti causes skin tumors in donkeys. A protozoan related to Toxoplasmosis little is known about transmission. Diagnosis can be made by serology, PCR, or microscopic examination of the tumor. So far treatment with the usual antiprotozoals have not been curative. This report is of an outbreak in a group of donkeys in the UK. Similar occurrences have been seen in the US and the incidence seems to be rising.
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First record of besnoitiosis caused by Besnoitia bennetti in donkeys from the UK
Parasit Vectors. 2020 Jun 3;13(1):279.
Authors
Hany M Elsheikha 1 , Gereon Schares 2 , Georgios Paraschou 3 , Rebekah Sullivan 4 , Richard Fox 5
Affiliations

1 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK. hany.elsheikha@nottingham.ac.uk.
2 Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Greifswald-Insel Riems, Germany. gereon.schares@fli.de.
3 Pathology Department, The Donkey Sanctuary, Brookfield farm, Offwell, Honiton, Devon, UK.
4 Veterinary Department, The Donkey Sanctuary, Brookfield farm, Offwell, Honiton, Devon, UK.
5 Finn Pathologists, Unit 3c, 3 Mayflower Way, Harleston, Norfolk, UK.

Free PMC article
Abstract

Background: The involvement of Besnoitia bennetti in skin pathologies was investigated in a series of 20 donkeys from the Donkey Sanctuary in England, in the 2013-2019 period.

Methods: The initial histopathological finding of Besnoitia cysts in skin lumps that were presumed to be sarcoids in 2013 triggered our cognisance of this parasite and resulted in identification of a total of 20 cases. Histopathological examination of surgical biopsy samples collected from 8 live donkeys and tissue specimens from 12 deceased donkeys at post-mortem examination revealed the presence of Besnoitia cysts in all 20 donkeys. The indirect fluorescent antibody test (IFAT) and immunoblotting analysis showed the presence of anti-Besnoitia antibodies in archived serum samples from 4 deceased donkeys. Additionally, infection was evidenced in one live donkey based on IFAT and immunoblot analysis of tissue fluid of a dermal mass containing Besnoitia cysts, and real-time (RT)-PCR analysis and microsatellite genotyping of DNA isolated from the tissue of the same dermal mass confirmed the infection specifically as B. bennetti.

Results: Both serological and microsatellite analyses confirmed the aetiology to be B. bennetti. Our findings suggested that in cases of skin masses such as sarcoids, the suspicion of B. bennetti infection should be borne in mind even when clinical and histopathology examination results are negative in order to avoid misdiagnosis.

Conclusions: This case series documents, to our knowledge, the first report of B. bennetti infection in donkeys in the UK, indicating that donkey besnoitiosis has become noteworthy in the UK. Further investigations of the occurrence, epidemiological characteristics, and clinical manifestations of B. bennetti infection in donkeys and other equids are warranted.

Keywords: Besnoitia bennetti; Donkey; Histopathology; Microsatellite typing; Specific anti-Besnoitia antibodies; Tissue cysts.