Molecular Identification of Trypanosoma evansi Isolated from Arabian Camels (Camelus dromedarius) in Riyadh and Al-Qassim, Saudi Arabia

SIMPLE SUMMARY: We investigated the occurrence of the parasite Trypanosoma evansi in camels in Saudi Arabia. Despite being undetectable in thin blood smears obtained from the camels, polymerase chain reaction findings show that nearly half the camels were infected with parasites. Infection causes a significant financial burden to camel breeders and owners. Detection of the parasite reduces financial losses and improves camel mortality. We conclude that polymerase chain reaction is more effective than microscopy at identifying T. evansi infection in camels. ABSTRACT: We analyzed the blood from 400 one-humped camels, Camelus dromedarius (C. dromedarius), in Riyadh and Al-Qassim, Saudi Arabia to determine if they were infected with the parasite Trypanosoma spp. Polymerase chain reaction (PCR) targeting the internal transcribed spacer 1 (ITS1) gene was used to detect the prevalence of Trypanosoma spp. in the camels. Trypanosoma evansi (T. evansi) was detected in 79 of 200 camels in Riyadh, an infection rate of 39.5%, and in 92 of 200 camels in Al-Qassim, an infection rate of 46%. Sequence and phylogenetic analyses revealed that the isolated T. evansi was closely related to the T. evansi that was detected in C. dromedarius in Egypt and the T. evansi strain B15.1 18S ribosomal RNA gene identified from buffalo in Thailand. A BLAST search revealed that the sequences are also similar to those of T. evansi from beef cattle in Thailand and to T. brucei B8/18 18S ribosomal RNA from pigs in Nigeria.