Kinetoplastid Biology and Disease

A nested polymerase chain reaction (nPCR)-based assay, was developed and evaluated for rapid detection of Trypanosoma evansi in experimentally infected mice and naturally infected camels (Camelus dromedarius). Four oligonucleotide primers (TE1, TE2, TE3 and TE4), selected from nuclear repetitive gene of T. evansi, were designed and used for PCR amplifications. The first amplification, using a pair of outer primers TE1 and TE2, produced a 821-bp primary PCR product from T. evansi DNA. The second amplification, using nested (internal) pair of primers TE3 and TE4, produced a 270-bp PCR product. T. evansi DNAs extracted from blood samples of experimentally infected mice and naturally infected Sudanese breed of dromedary camels were detected by this nested PCR-based assay. The nested primers TE3 and TE4 increased the sensitivity of the PCR assay and as little as 10 fg of T. evansi DNA (equivalent to a single copy of the putative gene of the parasite) was amplified and visualized onto ethidium bromide-stained agarose gels. Amplification products were not detected when the PCR-based assay was applied to DNA from other blood parasites including Thieleria annulata, Babesia bigemina or nucleic acid free samples. Application of this nPCR-based assay to clinical samples resulted in direct detection of T. evansi from a variety of tissue samples collected from experimentally infected mice and blood from naturally infected camels. The described nPCR-based assay provides a valuable tool to study the epidemiology of T. evansi infection in camels and other susceptible animal populations. Background Trypanosoma evansi (T. evansi), the cause of trypanosomiasis (Surra), constitutes one of the major veterinary problems worldwide. The disease causes significant morbidity and mortality in camels in the Sudan, which has a population of over 3 million camels [1]. trypanosomiasis in camels occurs both in chronic and acute forms [2]. The chronic form of the disease is most common and is likely to be associated with secondary infections due to immunosuppression [3]. Clinical signs and pathological lesions caused by T. evansi in camels are unreliable for definitive diagnosis [4]. In addition, detection of parasites in the blood is difficult because parasitaemia is intermittent [5]. Serological tests have been developed and evaluated for diagnosis of trypanosomiasis in camels. They include card agglutination test and enzyme-linked immunosorbent assay (Ab-ELISA) [6-8]. In general serological techniques are useful for detection of a past infection but not for Published: 20 May 2006 Kinetoplastid Biology and Disease 2006, 5:2 doi:10.1186/1475-9292-5-2 Received: 04 November 2005 Accepted: 20 May 2006 This article is available from: http://www.kinetoplastids.com/content/5/1/2 © 2006 Aradaib and Majid; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.