Preliminary application and evaluation of loop-mediated isothermal amplification ( LAMP ) for detection of bovine theileriosis and trypanosomosis in Tanzania

THEKISOE, O.M.M., OMOLO, J.D., SWAI, E.S., HAYASHIDA, K., ZHANG, J., SUGIMOTO, C. & INOUE, N. 2007. Preliminary application and evaluation of loop-mediated isothermal amplification (LAMP) for detection of bovine theileriosis and trypanosomosis in Tanzania. Onderstepoort Journal of Veterinary Research, 74:339–342 The sensitivity of LAMP, PCR and microscopy to detect Theileria spp. and Trypanosoma congolense in field-derived bovine blood samples from Tanzania was evaluated and compared. No parasites were detected by microscopy. Furthermore, no bovine Theileria spp. were detected by LAMP and PCR from all the 24 samples collected from Arusha. Four and one out of 24 samples were positive for Theileria congolense infection by LAMP and PCR respectively while, 18 and nine out of 40 samples from Dar es Salaam were positive by LAMP and PCR for Theileria spp. Infection, respectively. Although all samples from Dar es Salaam were negative for Trypanosoma congolense infections by PCR, 12 out of 40 samples were LAMP positive. Whilst PCR is an established gene amplification method for the detection of Theileria and trypanosome parasites, this study introduces LAMP as an alternative molecular diagnostic tool that could be used in large-scale epidemiological surveys.

and compared the sensitivity of LAMP, PCR and micro scopy for the detection of bovine theileriosis and trypanosomosis (T.congolense) from cattle samples collected from Tanzania's Arusha and Dar es Salaam farms.
Forty blood samples blotted on filter papers (FTA® card, Whatman, UK) and thin blood smears were prepared from blood collected from cattle of unknown age on ten farms near Dar es Salaam and 24 samples from cattle on seven farms near Arusha (animal age ranged between 4 months and 8 years).Genomic DNA used in LAMP primer specificity and sensitivity tests was extracted according to Sam brook & Russel (2001).The blood samples dried on filter papers were purified according to the manufacturer's instructions and then used as a DNA template.The LAMP primer sets used in the current study were designed from T. parva HSP70 (Accession no.U40190) and T. congolense 18S rRNA (Accession no.U22315) using Primer Explorer V2 (Fujitsu, Japan), with the following sequences: LAMP primer set for T. parva HSP70 FIP: 5'-TGG GTT ACG GGC TTC TTG GTT TCC TAC GTC GCA TTC ACT GAC-3'; BIP: 5'-ATT TTC GAC GCC AAG AGG CTC AAA TGG CCA GTG CTT CAT GTC-3'; F3: 5'-GGA AAC AGG ACA ACG CCG-3', and B3: 5'-CCG TTT GGT CCG TTG GTA A-3'.
Both LAMP and polymerase chain reaction (PCR) (F3 and B3 LAMP primers were used as the PCR primer pair) were conducted as described by Kuboki, Inoue, Sakurai, Di Cello, Grab, Suzuki, Sugimoto & Igarashi (2003).For PCR, DNA was extracted from filter papers using Qiagen kit according to the manufacture's instructions (QiAamp DNA Mini Kit, Qi-agen®; Maryland, USA).
LAMP primer sets designed from HSP70 of T. parva amplifies the major bovine Theileria spp.except T. orientalis DNA (Fig. 1A) and are highly sensitive for the detection of Theileria DNA (Fig. 1B).These primers can therefore be used as universal primers for gene amplification of bovine Theileria spp.DNA.LAMP primers for T. congolense are also highly sensitive and specific (O.M.M. Thekisoe & N. Inoue, unpublished data 2006).
During the collection of the samples in Arusha, no ticks were observed on the sampled animals which probably explains the absence of Theileria spp.infections by diagnostic methods used in this study (Table 1).There were no antibodies detected by the indirect fluorescent antibody test (IFAT) against Thei leria spp. in seven serum samples collected from animals in Arusha (data not shown).In contrast, the fact that Theileria spp.were detected from the Dar es Salaam samples (Table 1) is not surprising as bovine Theileria infections are common in this region (Msami 2001;Swai, French, Karimuribo, Fitzpatrick, Bryant, Brown & Ogden 2005).It has also been reported that animals which survive T. parva infections remain reservoirs of the parasite (Swai et al. 2005).Our study revealed a low prevalence of T. congolense infections in Arusha (Table 1).However, antibodies against T. congolese were detected using enzyme-linked immunosorbent assay ELISA (Bannai, Sakurai, Inoue, Sugimoto & Igarashi 2003) from five out of seven serum samples collected from animals with a previous history of trypanosome infections in Arusha (data not shown).There was a significantly higher prevalence of T. congolense infections detected by LAMP and PCR in Dar es Salaam as compared to Arusha (Table 1).In conclusion, LAMP showed higher detection sensitivity than PCR and microscopy, as has previously been reported (Kuboki et al. 2003) of positively detected samples ** Thin blood smear This study further confirms the presence of T. congolense in sampled areas of Tanzania as previously reported (Malele, Craske, Knight, Ferris, Njiru, Hamilton, Lehane, Lehane & Gibson 2003), which is mainly due to wide distribution of different tsetse fly species infesting about 60 % of the country (Mugittu et al. 2001).No parasites were detected by microscopic examination of Giemsa-stained thin blood smears from all the sampled cattle in both Arusha and Dar es Salaam.

TABLE 1
Detection performance of LAMP, PCR and thin blood smears