Researchers in Iran have confirmed that camels can be infected by Theileria equi, which causes equine piroplasmosis in horses.
The study team from the Shahid Chamran University of Ahvaz set out to determine the prevalence of T. equi among dromedary camels in central Iran, where many camels and horses are raised and equine piroplasmosis is prevalent.
T. equi, and another protozoan, Babesia caballi, are behind the protozoan disease. It is considered one of the most important protozoan diseases to affect horses, mules, and donkeys worldwide.
The disease has a major impact on equine productivity, reducing breeding capability and athletic performance in equids globally.
The Iranian researchers, in previous work, have shown that equine piroplasmosis is a significant problem in the area, with an overall molecular prevalence of T. equi in horses in the region found to be 22.86%.
It is spread by ticks and, once infected, the protozoan can infect foals through the placenta. Transmission is also possible through contaminated needles and surgical instruments.
The study team, writing in the Archives of Razi Institute, observed that since carrier animals were a major source of infection, accurate diagnosis of carriers was necessary for disease prevention.
The researchers took blood samples from 161 camels for their research to check for evidence of T. equi infection.
Microscopic examination of blood smears revealed that one of the camels was positive for the intraerythrocytic stage of Theileria infection – that is, situated or occurring within the red blood cells, pointing to an acute phase in the infection.
However, testing at a molecular level, using the polymerase chain reaction method, detected T. equi in seven of the camels, representing 4.3% of those tested.
Genetic analysis of T. equi from the camels indicated it was almost identical to that in horses, raising the prospect of interspecies transmission.
“In conclusion,” they wrote, “this study demonstrated that T. equi infection is present among Iranian camels; also, the camels shared piroplasms with horses in the studied regions.
“Although it is too early to conclude, the possibility of natural T. equi infection among camels may complicate the epidemiology of equine theileriosis [piroplasmosis].
“Therefore, further studies are required to decide if tick vectors are able to transfer T. equi from infected camels and cause infection in horses.
“Overall,” they continued, “we should determine which tick species are responsible for the transmission of diseases to and/or between camels.”
They noted it was well established that several tick species infested both camels and horses and played a possible role in the transmission of protozoan infections.
Prevalence and phylogenetic analysis of Theileria equi in Iranian dromedaries
Bahrami, S., Tabandeh, M.R., Nikbin, A., Alborzi, A.R., Ghadrdan, A.R.
Archives of Razi Institute. 2016;71(3)169-175 DOI 10.22034/ari.2016.106970
The full study, available under a Creative Commons License, can be read here.