Evaluation of Xpert® MTB/RIF assay as a diagnostic test for pulmonary tuberculosis in children in Myanmar.

BACKGROUND: The Xpert® MTB/RIF assay has been recommended for the diagnosis of pulmonary tuberculosis (PTB). However, there are limited data from the South-East Asian region. SETTING: This study was carried out at a tertiary-level children's hospital in Mandalay, Myanmar. OBJECTIVE: To evaluate the performance of Xpert as a diagnostic test for PTB in children. METHODS: A cross-sectional descriptive study of children with suspected PTB. Gastric lavage aspirate samples were tested using Xpert, solid culture and smear microscopy. The performance of Xpert, solid culture and smear microscopy were evaluated using the revised National Institute of Health classification for intrathoracic TB in children as the reference standard. RESULTS: TB was bacteriologically confirmed in 38 (16.5%) of 231 children with suspected PTB. Of the 38 children with confirmed TB, 36 cases were identified using Xpert, 16 using solid culture and 12 using smear microscopy. With confirmed TB as the reference standard, the sensitivity of Xpert, solid culture and smear microscopy was respectively 94.7% (95%CI 80.9-99.1), 42.1% (95%CI 26.7-59.1) and 31.6% (95%CI 18.0-48.8). CONCLUSION: Xpert has improved the bacteriological confirmation of PTB among hospitalised children in Myanmar.

Clinical, virological and epidemiological characterization of dengue outbreak in Myanmar, 2015.

Hospital-based surveillance was conducted at two widely separated regions in Myanmar during the 2015 dengue epidemic. Acute phase serum samples were collected from 332 clinically diagnosed dengue patients during the peak season of dengue cases. Viremia levels were measured by quantitative real-time PCR and plaque assays using FcγRIIA-expressing and non-FcγRIIA-expressing BHK cells to specifically determine the infectious virus particles. By serology and molecular techniques, 280/332 (84·3%) were confirmed as dengue patients. All four serotypes of dengue virus (DENV) were isolated from among 104 laboratory-confirmed patients including two cases infected with two DENV serotypes. High percentage of primary infection was noted among the severe dengue patients. Patients with primary infection or DENV IgM negative demonstrated significantly higher viral loads but there was no significant difference among the severity groups. Viremia levels among dengue patients were notably high for a long period which was assumed to support the spread of the virus by the mosquito vector during epidemic. Phylogenetic analyses of the envelope gene of the epidemic strains revealed close similarity with the strains previously isolated in Myanmar and neighboring countries. DENV-1 dominated the epidemic in 2015 and the serotype (except DENV-3) and genotype distributions were similar in both study sites.

Field trial of efficacy of local compression immobilization first-aid technique in Russell's viper (Daboia russelii siamensis) bite patients.

A field trial of efficacy of local compression immobilization first-aid technique in 42 Russell's viper bite cases was studied and only 19 were envenomed. Proper immobilization was carried out in 3/13 immobilized cases. The average time of application of the pad was 1.12 hours (range 5 minutes to 7 hours) and the total duration of the pad application was 3 hours 40 minutes (range 30 minutes to 9 hours). Venom levels measured at the hospital before and at 15 and 30 minutes after release of the pad (n=10) showed a rise of 5 to 30 ng/ml of venom following release. Movement of venom antigen was found to be retarded in all cases (n=9) whose venom levels were measured at 15 and 30 minutes with the pad in place. Sixteen out of 19 cases had systemic envenoming, indicating that pad or immobilization alone is not effective in delaying spread of venom. The incidence of local necrosis 3/42 (8%) following use of the pad was comparable to that of the systemic cases without the pad. No ill effects were observed following its application for as long as 9 hours. Local blackening seen in 4/36 (10%) cases was likely to be result of a local venom effect.

Envenoming by Chinese krait (Bungarus multicinctus) and banded krait (B. fasciatus) in Myanmar.

A retrospective study of 8 cases of envenoming by Chinese krait (Bungarus multicinctus) and one banded krait (B. fasciatus) in southern Myanmar is reported. Chinese krait bite produced minimal local reactions, except in one person bitten on the lip which resulted in local swelling. Onset of neurotoxic symptoms occurred 2.5-6 h after the bite, and the interval between bite and death ranged from 12-30 h. Three deaths were due to respiratory failure. Four mildly envenomed cases recovered spontaneously without assisted ventilation. One severely envenomed patient recovered after 8 d intensive respiratory care. Cobra (Naja kaouthia) antivenom had no value in reversing neurotoxic symptoms. Anticholinesterase injection given to one patient failed to improve neurotoxic symptoms. The bite of banded krait (B. fasciatus) resulted in neurotoxic envenoming within 2 h after the bite, with minimal local reactions. The victim died of respiratory failure 14 h after the bite.

Mechanism of suppression of normal hemopoietic activity by lymphokine-activated killer cells and their products.

Interleukin 2 (IL-2)-activated lymphocytes (lymphokine-activated killer [LAK] cells) have been shown to inhibit the formation of autologous human granulocyte-macrophage hemopoietic progenitors (granulocyte-macrophage colony-forming units, CFU-GM) in vitro. Effects of LAK cells on these progenitors may include a number of different mechanisms. LAK cells are potent cytotoxic lymphocytes capable of lysing certain normal autologous cells. They also produce cytokines known to inhibit hemopoiesis (interferon gamma [IFN-gamma] and tumor necrosis factor alpha [TNF-alpha]) or enhance it (granulocyte-macrophage colony-stimulating factor, GM-CSF). In our current study we analyzed the mechanism of suppression of autologous CFU-GM by LAK cells. Our results suggest that LAK cells are not directly cytotoxic to normal CFU-GM. We show that it is possible to abolish the hemopoiesis-inhibiting activity of LAK cells without abrogating their cytotoxicity against tumor cell lines using inhibitors of DNA synthesis, namely hydroxyurea or irradiation.

Antilymphocyte globulin therapy enhances impaired function of natural killer cells and lymphokine activated killer cells in aplastic anaemia.

MHC-unrestricted cytotoxic lymphocytes, namely natural killer (NK) and lymphokine activated killer (LAK) cells, have been implicated in the regulation of haemopoiesis. To investigate the possible role of these lymphocytes in the pathogenesis of aplastic anaemia (AA), we studied their functions in the peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) of patients with AA treated with antilymphocyte globulin (ALG). Before treatment, both NK and LAK activities in the PBMC of 25 patients were low (NK = 1.9 +/- 2.1 x 10(3) LU/l) LAK = 4.7 +/- 3.6 x 10(3) LU/l) compared to normal (NK = 6.0 +/- 3.0 x 10(3) LU/l, LAK = 10.0 +/- 3.5 x 10(3) LU/l) or multiply transfused (NK = 7.8 +/- 6.6 x 10(3) LU/l, LAK = 25.2 +/- 13.6 x 10(3) LU/l) controls. The NK and LAK activities in the BMMC in AA patients were not significantly different from those in PBMC. In all patients with low LAK and NK activities pre ALG there was an increase in activity 2-24 weeks after therapy which eventually reached normal levels and which was maintained for up to 2 years. Analysis of lymphocyte phenotypes in AA patients before treatment showed both significantly low mean proportion and absolute numbers of CD16+ cells compared to normals, which increased after therapy. Changes in MHC-unrestricted cytotoxicity and lymphocyte phenotypes post therapy were not correlated with haemopoietic recovery. These data suggest that ALG treatment can enhance the functions of MHC-unrestricted lymphocytes independently from haemopoiesis. It is unlikely that these cells play a role in the pathogenesis of AA.