TREATMENT FAILURE EQUINE TAPEWORMS TABLE 2
moxidectin (0.4 mg/kg) and praziquantel (2.5 mg/kg) in July and August. July
Horse ID G
H L
M R T
U V
W T B I
P C
O Q S
Sex
Female Female Female Female Male Male Male Male Male Male
Female Female Female Female Female Male Male
Pre- treatment 0
0 0 0 0
150 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
Post- treatment N/A
0
N/A 5 0
145 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
Note : Horses with N/A in the counts section did not have a faecal submitted for counting.
that the equine tapeworm life- cycle includes an intermediate host, the oribatid mite, which resides on pastures. The presence of this mite could mean persistence of drug- resistant tapeworm populations within the fields long after the afflicted horses have been removed. A prominent question is which anthelmintic to ad- minister in cases of loss of efficacy of currently available prod- ucts. While there are no alternative anthelmintics for tapeworms globally available for equines, in Japan an approved anthelmintic, a bithionol paste, was demonstrated to reduce tapeworm burdens by 87% at 5 mg/kg and 100% at 10 mg/kg (Toguchi et al., 2004 ). This product could be of interest in other countries as an alterna- tive to the current anthelmintic portfolio for tapeworm treatment, though it currently is no longer on the market (Sanada et al., 2009 ; Toguchi et al., 2004 ). In summary, this study has documented evidence of treatment
failure against equine anoplocephalid tapeworms to two different drug classes and three different anthelmintic formulations. These findings add to a growing body of evidence suggesting emerging anthelmintic resistance in equine tapeworms. A standardised fae- cal egg count reduction test is needed for equine tapeworm eggs to better characterise and quantify these findings, and more studies are needed to evaluate treatment efficacy in different regions, horse breeds and age groups.
AUTHOR CONTRIBUTIONS C. Finnerty and M. Nielsen contributed to study design, study execu- tion, data analysis and interpretation and preparation of the manu- script. S. Bonometti contributed to study execution and preparation
of the manuscript. N. Ripley contributed to study design and study execution. M. Smith contributed to study execution. All authors gave their final approval of the manuscript.
ACKNO WLE DGE MENTS A special thanks to Dr Bruno Menarim Carvalho for assisting with study logistics. Additionally, a huge thanks to the staff of the Thoroughbred breeding facility for diligent sample collection and animal management.
FUNDING INFORMATION This case study was not financially supported.
CONFLICT OF INTEREST STATEMENT The authors declare no conflict of interest.
ETHICS STATEMENT Ethical review is not appropriate for this case study.
ORCID Constance A. Finnerty
https://orcid.org/0009-0003-6743-9958 Martin K. Nielsen
https://orcid.org/0000-0002-8942-6803
REFERENCES
Abbott , J.B. , Mellor , D.J. , Barrett , E.J. , Proudman , C.J. & Love , S. ( 2008 ) Serological changes observed in horses infected with Anoplocephala perfoliata after treatment with praziquantel and natural reinfection . Veterinary Record , 162 ( 2 ), 50 – 53 .
| 583 July Pre and post- faecal egg counts using Mini- FLOTAC tapeworm faecal egg counts before and 14 days after administration of August
Pre- treatment 0
N/A 0
N/A 5 0
10 5 0 0
10 25 0 0
10 0 0
Post- treatment 0
N/A 0
N/A 0 5
N/A 10
N/A 5 5
10 0 0 5 0
N/A
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