Among them, the pCS20 real-time PCR TaqMan probe assay provides the best sensitivity with a detection limit of one gene copy per reaction, which is 100 times higher than that of conventional pCS20 PCR [20]. However, this assay was reported to cross-react with both E. chaffeensis and E. canis [20]. Moreover, although this assay performs well in the sensitive detection and quantification of E. ruminantium, it is not readily transferable

to low-technology settings where there is limited access to expensive fluorescence detector based thermocyclers. Loop-mediated isothermal amplification (LAMP) assay is a rapid DNA amplification method originally developed by Notomi et al. [21], and it has been applied for the detection of viral [22, 23], bacterial [24, 25], fungal [26], and parasitic agents [27,

selleck products 28], but it has never previously been applied to rickettsial agents. The method requires a specially designed primer set that recognizes at least six independent regions of the target gene, which increases the specificity as well as the rapidity of the reaction. LAMP results are visualized by turbidity that can be seen by the naked eye [29], and optionally by agarose gel electrophoresis or by addition of fluorescent dyes visualized under UV light [30, 31]. Since the Bst DNA polymerase used in LAMP allows strand displacement-DNA synthesis, LAMP reactions are performed under isothermal conditions using a simple incubator, such as a water bath or heating block. Furthermore, LAMP reagents are relatively stable for a month, even when stored at 37°C, which is a warmer temperature than recommended by the manufacturer [32]. With these advantages, LAMP MG-132 clinical trial has the potential to be used even in clinical laboratories often poorly equipped, facing problems of constant electricity supply in tropical and sub-tropical countries where heartwater is endemic. The purpose of the present study was to develop LAMP assays for the detection science of E. ruminantium and to evaluate the diagnostic sensitivity

and specificity of these assays using a panel of bacterial DNA samples, quantitated plasmid standards, and field samples derived from both animal blood and ticks. The newly developed LAMP assays successfully detected E. ruminantium with rapidity, specificity, and high sensitivity. Results Optimization of LAMP The reactions for both pCS20 and sodB LAMP were performed under isothermal conditions at a range of 58 to 66°C using plasmid DNA (106 copies per reaction) for 120 min, with monitoring of the turbidity. Although amplifications with the LAMP assays were observed at all temperatures tested, the reactions reached the threshold value (0.1) with the shortest incubation times at 61°C for pCS20 and 63°C for sodB (data not shown). No nonspecific amplification was detected for the negative cell culture until after at least 120 min incubation. Thus, subsequent LAMP reactions were conducted at these temperatures for 60 min.