Bio-efficacy of Long Lasting Insecticidal Mosquito Nets (LLINs) on Malaria Vector Anopheles Mosquitoes in Malaria-Endemic Areas of Myanmar

Sixty used Long Lasting Insecticidal Nets (LLINs) from six malaria endemicareas of States and Regions of Myanmar were assessed for their bio-efficacy againstAnopheles mosquitoes. Total ten nets were collected from the randomly selectedhousehold of each area. Insecticide susceptibility and bio-efficacy test were doneaccording to WHO testing method. Results revealed that a total of 4470 mosquitoes of 12Anopheles species including main vector and secondary vectors were collected in highdensity in Beelin, Taungoo, Pyin Oo Lwin, Kamamaung and Hpa-an. All collectedmosquitoes were found susceptible to insecticides as recommended by the WHO. Bioefficacy of PermaNet 2.0, DAWA TANA, Yorkool, BASF, Net protect and Yahe LLINs netswere 12(100%), 11/12(91.67%), 4(100%), 8(100%), 5(100%) and 19(100%)respectively. The DAWA TANA net had 20% sensitivity after repetitive washing. Thesensitivity of LLINs nets was higher for all selected areas of States and Regions inMyanmar. The study suggested that there is need to distribute a large number of effectiveLLINs nets in malaria endemic areas as well as the replacement of expired, less effectiveand very old LLINs nets with a new one is also necessary. LLINs nets are very effectiveAnopheles mosquitoes control tools and it can reduce the human-vector contact effectively.Moreover, research on bio-efficacy evaluations of the LLINs nets is required regularly tomaintain and control the transmission of malaria through Anopheles mosquitoes.

Peripheral neuropathy induced by drinking water contaminated with low-dose arsenic in Myanmar

BACKGROUND@#More than 140 million people drink arsenic-contaminated groundwater. It is unknown how much arsenic exposure is necessary to cause neurological impairment. Here, we evaluate the relationship between neurological impairments and the arsenic concentration in drinking water (ACDW).@*PARTICIPANTS AND METHODS@#A cross-sectional study design was employed. We performed medical examinations of 1867 residents in seven villages in the Thabaung township in Myanmar. Medical examinations consisted of interviews regarding subjective neurological symptoms and objective neurological examinations of sensory disturbances. For subjective neurological symptoms, we ascertained the presence or absence of defects in smell, vision, taste, and hearing; the feeling of weakness; and chronic numbness or pain. For objective sensory disturbances, we examined defects in pain sensation, vibration sensation, and two-point discrimination. We analyzed the relationship between the subjective symptoms, objective sensory disturbances, and ACDW.@*RESULTS@#Residents with ACDW ≥ 10 parts per billion (ppb) had experienced a "feeling of weakness" and "chronic numbness or pain" significantly more often than those with ACDW  50 ppb). These data suggest a threshold for the occurrence of peripheral neuropathy due to arsenic exposure, and indicate that the arsenic concentration in drinking water should be less than 10 ppb to ensure human health.

Current Status of Standard Diagnostics and Treatment for Malaria, Tuberculosis, and Hepatitis in Myanmar

Malaria, tuberculosis, and hepatitis are common and notorious infectious diseases in Myanmar. Despite intensive efforts to control these diseases, their prevalence remains high. For malaria, which is a vector-borne disease, a remarkable success in the reduction of new cases has been achieved. However, the annual number of tuberculosis cases has increased over the last few decades, and the prevalence of chronic viral hepatitis infection has been high in Myanmar and other nearby countries. Early detection and prompt treatment are crucial to control these diseases. We have devoted our research efforts to understanding the status of these infectious diseases and working towards their eventual elimination for the last four years with the support of the Korea International Cooperation Agency. In the modern era, an infection that develops in one geographical area can spread globally because national borders do not effectively limit disease transmission. Our efforts to understand the status of infectious diseases in Myanmar will benefit not only Myanmar but also neighboring countries such as Korea.

Comparison of microscopy and PCR for the detection of human Plasmodium species and Plasmodium knowlesi in southern Myanmar

Objectives To determine the distribution of Plasmodium (P) species including Plasmodium knowlesi and to compare the specificity and sensitivity of microscopy with nested PCR in malaria diagnosis. Methods The study was conducted in Kawthaung, southern Myanmar. Ninety clinically suspected malaria patients were screened for malaria by Giemsa stained microscopy and confirmed by nested PCR. Results Among the participants, 57 (63.3%) were positive and 33 (36.7%) were negative by microscopy. Of positive samples, 39 (68.4%) were Plasmodium falciparum, 17 (29.8%) Plasmodium vivax and 1 (1.8%) Plasmodium malariae, whereas 59-amplified by PCR were 40 (67.8%), 18 (30.5%) and 1 (1.7%) respectively. PCR amplified 2 microscopy negative samples. Two samples of P. falciparum detected by microscopy were amplified as P. vivax and vice versa. All samples were negative for Plasmodium ovale, P. knowlesi and mixed infections. Microscopy had a very good measure of agreement (κ = 0.95) compared to nested PCR. Sensitivity and specificity of microscopy for diagnosis of P. falciparum were 92.5% (95% CI: 79.6–98.4) and 96.0% (95% CI: 86.3–99.5) respectively, whereas for P. vivax were 83.3% (95% CI: 58.6–96.4) and 97.2% (95% CI: 90.3–99.7). Conclusions P. knowlesi was not detected by both microscopy and PCR. Giemsa stained microscopy can still be applied as primary method for malaria diagnosis and is considered as gold standard. As to the lower sensitivity of microscopy for vivax malaria, those with previous history of malaria and relapse cases should be diagnosed by RDT or PCR combined with microscopy. Inaccuracy of species diagnosis highlighted the requirement of training and refresher courses for microscopists.

Effective High-Throughput Blood Pooling Strategy before DNA Extraction for Detection of Malaria in Low-Transmission Settings

In the era of (pre) elimination setting, the prevalence of malaria has been decreasing in most of the previously endemic areas. Therefore, effective cost- and time-saving validated pooling strategy is needed for detection of malaria in low transmission settings. In this study, optimal pooling numbers and lowest detection limit were assessed using known density samples prepared systematically, followed by genomic DNA extraction and nested PCR. Pooling strategy that composed of 10 samples in 1 pool, 20 µl in 1 sample, was optimal, and the parasite density as low as 2 p/µl for both falciparum and vivax infection was enough for detection of malaria. This pooling method showed effectiveness for handling of a huge number of samples in low transmission settings (<9% positive rate). The results indicated that pooling of the blood samples before DNA extraction followed by usual nested PCR is useful and effective for detection of malaria in screening of hidden cases in low-transmission settings.

Determination of phytochemical constituents and antioxidant activity of Rasayana, Triphala and antiageing herbal plants.

Antioxidants possess the ability to protect the body from damage caused by free radical induced oxidative stress and have antiageing property. ‘Theinga Dara Thanhitar’ book, written by Ashin Nagathein described that ‘Rasayana and Triphala’ drugs have the ability to prevent ageing and illness. This study was carried out to investigate the antioxidant activities of commonly used ingredients of ‘Rasayana’ such as Streblus asper Lour. (Okhne), Cassia fistula Linn. (Ngu), Tinospora cordifolia Miers. (Sindone-Ma-Nwe), Asparagus racemosus Willd. (Shin-Matet), Boerhavia diffusa Linn. (Payan-Nawa), and ‘Triphala’ such as Phyllanthus emblica Linn. (Ze-Phyu), Terminalia chebula Retz. (Phan-Ga) and Terminalia belerica Roxb. (Thit-Saint). Their absorbances were evaluated using 1,1-diphenyl -2-picrylhydrazyl (DPPH) assay method by using spectrophotometer. Yield percents of these plants were ranging from 4.05% to 28.6%. The watery extracts of Okhne, Ngu, stem of Sindone-Ma-Nwe, tubor of Payan-Nawa, Ze-Phyu, Phan-Ga, and Thit-Saint contain phenols and tannins which have free radical scavenging activities. It was found that the bark and stem of Okhne, tubor of Payan-Nawa and ‘Triphala’ had the least IC50 value i.e. the best antioxidant potency. Therefore, the findings from this study supported the experience-based findings of antiageing activities in ‘Triphala’ and ‘Rasayana’ to be evidence-based.

Scenario of the twins with suspected congenital rubella syndrome (CRS) in Yangon, Myanmar

Rubella is a common cause of childhood rash and fever. Congenital rubella syndrome (CRS) can lead to deafness, heart disease, cataracts, and a variety of other permanent manifestations. In order to identify the disease burden of rubella infection, CRS surveillance among infants in Yangon was conducted for two consecutive years from December 2000 to December 2002, as a WHO-funded study. Among the 13 participating hospitals, the Special Care Baby Unit of the Central Women‘s Hospital in Yangon reported 17 infants with suspected CRS. Interestingly, three sets of twins with suspected CRS were reported. One ml of blood was collected from each infant after obtaining informed consent, then tested for the presence of rubella antibody (Immunoglobulin M and G) by the ELISA method, and for the presence of rubella viral RNA by the RT-PCR method. Furthermore, nucleotide sequencing and genotype identification of samples from two cases with positive rubella RNA were performed. All 3 sets of twins were IgM negative. However, rubella RNA was detected by RT-PCR in twin 1A who showed no obvious clinical signs, and in twin 2B who had patent ductus arteriosus, splenomegaly and hepatomegaly. Nucleotide sequences of PCR positive cases revealed genotype Ia sequences. Twin 2B was identified as having deafness of the left ear on audiometry assessment conducted at 5 years and 4 months of age. Both twins of twin set-2 were IgG positive at age 12 days, but turned out to be negative by the age of 9 months. Both twins of twin set-3 presented with splenomegaly and died before 2 months of age, probably due to other infections. Our findings revealed the different scenario of twins with suspected CRS. It is expected to serve as a valuable addition to the medical literature as there were very few reports on twins with CRS.

Genotype determination of three dengue type 2 virus strains from Myanmar by sequencing E/NSI gene junction.

Genotype of three dengue-2 virus strains from Myanmar was determined as genotype II by sequencing 240 nucleotide long fragment across the E/NS1 gene junction by the primer extension dideoxy chain termination method, applying direct sequencing of the PCR product. These strains were isolated from a dengue shock syndrome (DSS) patient and two patients with dengue hemorrhagic fever (DHF) grade 1, in Yangon (Rangoon), Myanmar (Burma), in 1987. Sequence homology of all three strains were highest (96%) to New Guinea C strain (genotype II), lesser homology (93%) to Jamaican 1409 strain (genotype III), and the least homology (91%) to PR 159/S1 strain (genotype I). Two DHF strains revealed only 2 nucleotide and 3 nucleotide differences compared with DSS strain, all at the 3rd position of the codons which resulted in silent mutations.