Worrying levels of the protozoan infection, equine piroplasmosis, have been detected in horses and donkeys in Egypt.
“The overall equine piroplasmosis incidence found in the population under study was relatively high,” Marta Silva and her colleagues reported in the journal, Parasites and Vectors.
Equine piroplasmosis is an infectious tick-borne disease of horses, mules, and donkeys caused by two protozoans, Theileria equi (formerly Babesia equi) and Babesia caballi. The disease is found in most tropical and subtropical areas, and in some temperate zones. It is considered one of the highest profile protozoan diseases affecting equids.
Clinical signs include weakness, loss of appetite, fever, anaemia, jaundiced mucous membranes, a swollen abdomen and laboured breathing. Horses that survive the acute infection phase may carry the parasites for an undetermined period of time in their blood.
The researchers from Washington State University and the Parasitology and Animal Diseases Department of Egypt’s National Research Center analysed blood samples from 88 horses and 51 donkeys using four methods – microscopic examination, an immunofluorescent antibody test, and two DNA-based tests.
Microscopic analysis revealed equine piroplasmosis infection in 11.4% of the horses and 17.8 % of the donkeys.
The antibody-related test detected T. equi in 23.9% of the horses and 31.4% of the donkeys. B. caballi was detected in 17% of the horses and, again, 31.4% of the donkeys.
The first DNA-based test found that 14.8% of the horses and 23.5% of the donkeys were positive to T. equi, but no cases of B. caballi were detected, most likely because of a difference in the gene sequence.
The second DNA-based test identified 36.4% of the horses and 43.1% of the donkeys as positive for T. equi, and 19.3% of the horses and 15.7% of the donkeys for B. caballi.
The overall incidence was relatively high and comparable regardless of the diagnostic method used, the study team reported.
They said the absence of reactivity using serum samples from Egyptian equines in one of the B. caballi DNA-based tests indicated that improvements in the serological detection of that protozoa was needed.
Assessment of Theileria equi and Babesia caballi infections in equine populations in Egypt by molecular, serological and hematological approaches
Mona S. Mahmoud, Nadia T. Abu El-Ezz, Sobhy Abdel-Shafy, Somia A. Nassar, Amira H. El Namaky, Wagdy K. B. Khalil, Don Knowles, Lowell Kappmeyer, Marta G. Silva and Carlos E. Suarez.
Parasites & Vectors 2016 9:260 DOI: 10.1186/s13071-016-1539-9