**3.2 Tuberculosis**

452 Current Topics in Tropical Medicine

*Trypanosoma brucei gambiense* or *Trypanosoma brucei rhodesiense* transmitted by tse-tse flies. The symptoms of HAT occur in 2 phases: hemolymphatic phase, followed by the neurological phase. If left untreated, the hemolymphatic phase permits the parasites to invade the central nervous system of the patient, resulting in fatal neurological symptoms such as coma and eventually death. Because no vaccine or preventative drug for HAT is available, and therapeutic drugs for HAT patients in the neurological phase causes severe

side effects, a simple and sensitive diagnostic method is in high demand.

Fig. 4. Diagram of the procedures involved in the PURE–LAMP system

Thirty-five microliters of control blood spiked with cultured parasites (*P. falciparum*, from ATCC) was treated with PURE and tested by *P. falciparum*-specific and Pan-genus LAMP. Left and right tubes contain the same parasite numbers and are those of Pf-LAMP and

Fig. 5. Sensitivity of PURE-Malaria-LAMP

Pg-LAMP, respectively.

Tuberculosis (TB) is one of the most threatening airborne diseases worldwide. One-third of the world's population is thought to be infected with *Mycobacterium tuberculosis* and new infections occur at a rate of about 1/second. Since the TB patients are concentrated in developing counties, including many tropical countries, TB is considered as a major poverty-related disease (Walker et al., 2003).

The sputum direct smear microscopy test is the only diagnostic method available for the detection of TB at peripheral laboratories in developing countries (Keeler et al., 2006). Because of the low sensitivity of the smear test, few patients with a low number of infected TB cells are often misdiagnosed as negative, thus preventing eradication of TB. In order to overcome this situation, we attempted to apply the novel platform PURE-LAMP system for the diagnosis of TB.

As summarized in Table 1, PURE-TB-LAMP provided positive results for both smear- and culture-positive sputum samples collected from patients suspected with TB. Furthermore,


Table 1. Summary of clinical performance of PURE-TB-LAMP

Sixty microliters of sputa obtained from patients suspected with TB in the Pham Ngoc Thach Hospital (PNTH; Vietnam) were analyzed by PURE-TB-LAMP. The performance of PURE-TB-LAMP was compared to those of the direct smear and culture method (Ogawa media) in terms of the positive ratios. Smear and culture tests for each sample were conducted according to the standardized protocols in PNTH.

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the PURE-TB-LAMP assay can detect the pathogen with 60% accuracy in smear-negative but culture-positive samples, and with 75% or more accuracy if 20 colonies are detected by the culture test using Ogawa media. This data clearly shows that the PURE-TB-LAMP method is reliable enough to be applied to the targeted peripheral smear centers in developing countries as an alternative method for the direct smear test.
