Biochemical and biological characterization of the venoms of Naja kaouthia and Naja mandalayensis from Myanmar and neutralization effects of BPI cobra antivenom

Snakebite is a neglected public health issue, with many scientific and medical issues to be solved. Cobras are among the most common venomous snakes in Myanmar and are responsible for a considerable number of severe snakebite envenoming. There are three species of cobra (Naja kaouthia, Naja mandalayensis and Ophiophagus hannah) in Myanmar. The study aims to characterize the N. kaouthia and N. mandalayensis venoms and to investigate the efficacy of anti-cobra antivenom (BPI) against the two venoms. Protein components and fibrinogenolytic activity were determined by SDS-PAGE. Enzymatic activities for PLA2, protease and acetylcholinesterase were determined by spectrophotometric method. Anticoagulant activity was determined by recalcification time of citrated human plasma. Myotoxicity, necrotizing activity, median lethal dose (LD50) and median effective dose (ED50) were determined by WHO recommended methods. The SDS-PAGE displayed the proteins and enzymes containing in two venoms were different. N. kaouthia venom exhibited more in PLA2, acetylcholinesterase, anticoagulant, fibrinogenolytic and necrotizing activities than N. mandalayensis venom. N. mandalayensis venom had more protease activity and myotoxicity than N. kaouthia venom. The median lethal dose (LD50) of N. kaouthia and N. mandalayensis venom was 4.33 μg/mouse and 5.04 μg/mouse respectively. Both venoms induced fibrinogen Aα chain degradation in 30 min (N. kaouthia) and in 6 h (N. mandalayensis). The same median effective dose (ED50) (19.56 μg/mouse) showed that anti-NK antivenom can neutralize against lethal effect of N. mandalayensis venom. It can also neutralize the protease activity, anticoagulant activity and fibrinogenolytic activity of both venoms. Immunodiffusion and immunoblotting studies showed that the antivenom recognized its homologous venom (N. kaouthia) and cross-reacted against the heterologous venom (N. mandalayensis). The anti-NK antivenom is suitable to use for N. mandalayensis bite if monospecific antivenom is not available.

Residual malaria among migrant workers in Myanmar: why still persistent and how to eliminate it?

BACKGROUND

Residual malaria is probably an important source for the re-emergence of malaria infection in the elimination era. Assessment to identify the factors influencing residual malaria in high-risk groups is needed to develop evidence-based decisions by stakeholders and policymakers.

METHODS

This study was conducted to explore the factors influencing the residual malaria infection among migrant workers in two sentinel sites (endemic vs. pre-elimination areas) in Myanmar using the mixed-model method.

RESULTS

A total of 102 migrant respondents (65 in Bamauk and 37 in Shwegyin) were included for the quantitative assessment using pretested questionnaires during household visits. Although 87.3% of them had insecticidal bed nets (ITNs/LLINs), only 68.3% of the migrants in Bamauk and 57.9% in Shwegyin used it regularly. The use of any bed net was high (79.9% in Bamauk vs. 91.0% in Shwegyin). The mean LLINs in their families were 1.64 (95%CI: 1.48-1.81) in Bamauk and 2.89 (95%CI: 2.67-3.11) in Shwegyin. Most of them received no health information for malaria prevention within the last year and their knowledge about malaria was low. Their working nature was a challenge for control measures against malaria in migrants.

CONCLUSION

The strategy for distributing LLINs and health promotion activities for mobile/migrant populations should be reviewed, and an appropriate action plan should be developed for the specific migrant group. Moreover, health promotion activities for behavior change communication should be strengthened in the migrant population in Myanmar.

Surge of severe acute respiratory syndrome coronavirus 2 infections linked to single introduction of a virus strain in Myanmar, 2020

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a major health concern globally. Genomic epidemiology is an important tool to assess the pandemic of coronavirus disease 2019 (COVID-19). Several mutations have been reported by genome analysis of the SARS-CoV-2. In the present study, we investigated the mutational and phylogenetic analysis of 30 whole-genome sequences for the virus's genomic characteristics in the specimens collected in the early phase of the pandemic (March-June, 2020) and the sudden surge of local transmission (August-September, 2020). The four samples in the early phase of infection were B.6 lineage and located within a clade of the samples collected at the same time in Singapore and Malaysia, while five returnees by rescue flights showed the lineage B. 1.36.1 (three from India), B.1.1 (one from India) and B.1.80 (one from China). However, there was no evidence of local spread from these returnees. Further, all 19 whole-genome sequences collected in the sudden surge of local transmission showed lineage B.1.36. The surge of the second wave on SARS-CoV-2 infection was linked to the single-introduction of a variant (B.1.36) that may result from the strict restriction of international travel and containment efforts. These genomic data provides the useful information to disease control and prevention strategy.