COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global health threat. Timely identification of infected cases is important for appropriate patient management and the control of viral spread. Simple and cost-effective tests are required to increase access to testing and early case detection. Here, we describe a colorimetric reverse transcription-loop-mediated isothermal amplification (RT-LAMP) method to detect SARS-CoV-2. The RT-LAMP could amplify the orf1ab sequence detectable by visual color change within 45 min at 63 °C. The limit of detection (LoD) for SARS-CoV-2 RNA was less than 100 copies (13.36) per reaction with no cross-amplification with other related viruses. Clinical evaluation using leftover RNA samples extracted from 163 nasopharyngeal swab specimens showed perfect agreement in negative (n = 124) and positive samples with cycle thresholds (Ct) < 34 cycles (n = 33) detected by real-time reverse transcription-polymerase chain reaction (RT-PCR), targeting RdRp and N genes as a reference. Overall, the diagnostic accuracy, sensitivity, specificity, positive and negative predictive values of RT-LAMP in testing were 96.32% (95% CI: 92.16-98.64%), 84.62% (95% CI: 68.47-94.14%), 100% (95% CI: 97.07-100.0%), 100% (95% CI: 89.42-100.0%), and 95.38% (95% CI: 90.22-98.29), respectively. This RT-LAMP assay is simple and reliable, with the potential to be an alternative for the rapid detection of SAR-CoV-2 with minimal time and fewer resources compared to real-time RT-PCR.

Tuberculosis (TB) continues to be a major public health problem in Thailand and many countries. Endemic TB and outbreaks of TB drug resistance in the borderlands are particularly important. The Thailand-Myanmar border has extensive cross-border travel that may accelerate TB’s spread. This cross-sectional study aimed to determine the frequency and factors associated with TB, and rifampicinresistant TB (RR-TB) among presumptive tuberculosis patients in Mae Sot Hospital. Sputum was processed by microscopic examination and Xpert MTB/RIF assay. Laboratory results and socio-demographic characteristics were collected and analyzed. Univariate and multivariate analyses were performed to assess the association of the risk factors with TB and RR-TB. The significant variables at p-values < 0.05 in univariate analysis were selected for multivariate analysis. Of 365 presumptive patients enrolled, 244 (66.85%) were males and 199 (54.52%) were Burmese. Of these, 314 (86.03%) were registered as new cases and 183 (50.14%) worked as laborers. Sputum microscopy was positive in 132 (36.16%) cases. Based on Xpert MTB/RIF, the frequency of TB was 136 (37.26%) and RR-TB was 15 (11.03%). TB was more common in males than females. The majority of the cases belonged to the 26-50-year-old age group and migrant workers. In RR-TB detection, the rpoB mutations covered by probe E were the most frequently observed. Sequencing showed that the most highly mutated codon was codon 531 and Ser531Thr was the most common mutation. For risk factor analysis, working as laborers was significantly (p-value < 0.05) associated with TB (aOR 2.83; 95% CI 1.43-5.63) and previously treated cases were significantly associated with RR-TB (aOR 12.33; 95% CI 2.29-66.49). The high frequency of TB and RR-TB in migrants highlights the problem and factors associated with TB at the border and the need for efforts in TB control programs in this setting.