Cholera in Yangon, Myanmar, 2012–2013

Aung, Wah Wah; Okada, Kazuhisa; Na-Ubol, Mathukorn; Natakuathung, Wirongrong; Sandar, Toe; Oo, Nan Aye Thidar; Aye, Moe Moe; Hamada, Shigeyuki

doi:10.3201/eid2103.141309

Cited by 5 publications

(5 citation statements)

References 9 publications

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“…Pulsotypes Y11-Y17 reported in this study were not previously observed in Yangon from 2012 to 2013. 17 However, the MLVA profiles of pulsotypes Y11, Y12, and Y15 showed a linkage in the cholera incidences between the two sites from 2014 to 2015, implying that the pathogen had originated in Yangon and disseminated to Mandalay within a span of 6 months. Interestingly, Mandalay and Yangon are located 600 km apart, and Yangon is located in the southern part of the country, at a distance of 40 km from the Gulf of Martaban in the Andaman Sea (Figure 3).…”

Section: Discussionmentioning

confidence: 96%

Molecular Epidemiology of Cholera Outbreaks during the Rainy Season in Mandalay, Myanmar

Roobthaisong¹,

Okada

Htun

et al. 2017

The American Journal of Tropical Medicine and Hygiene

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Cholera, caused by , remains a global threat to public health. In Myanmar, the availability of published information on the occurrence of the disease is scarce. We report here that cholera incidence in Mandalay generally exhibited a single annual peak, with an annual average of 312 patients with severe dehydration over the past 5 years (since 2011) and was closely associated with the rainy season. We analyzed cholera outbreaks, characterized 67 isolates of serogroup O1 in 2015 from patients from Mandalay, and compared them with 22 O1 isolates (12 from Mandalay and 10 from Yangon) in 2014. The isolates carried the classical cholera toxin B subunit (), the toxin-coregulated pilus A () of Haitian type, and repeat sequence transcriptional regulator () of El Tor type. Two molecular typing methods, pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analysis (MLVA), differentiated the 89 isolates into seven pulsotypes and 15 MLVA profiles. Pulsotype Y15 and one MLVA profile (11, 7, 7, 16, 7) were predominantly found in the isolates from cholera outbreaks in Mandalay, 2015. Pulsotypes Y11, Y12, and Y15 with some MLVA profiles were detected in the isolates from two remote areas, Mandalay and Yangon, with temporal changes. These data suggested that cholera spread from the seaside to the inland area in Myanmar.

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Section: Discussionmentioning

confidence: 96%

Molecular Epidemiology of Cholera Outbreaks during the Rainy Season in Mandalay, Myanmar

Roobthaisong¹,

Okada

Htun

et al. 2017

The American Journal of Tropical Medicine and Hygiene

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“…There are several caveats to these hypotheses; the rst being that whilst there were no known active cholera outbreaks in the Rakhine state at the time of the population displacement, it is a cholera endemic region (Ali et al, 2015;Lopez et al, 2020), and hence these isolates could have also originated from Myanmar. Notably, Myanmar experienced higher than normal rates of diarrheal disease in 2012 and 2013, and 23% and 14% of tested severe diarrheal cases were determined to be V. cholerae O1 (Aung et al, 2015). Molecular analysis showed that 34 isolates carried the classical ctxB type (ctxB1), suggesting the strains present in 2012 and 2013 may have belonged to PG 1.5, which would t with the dominance of this clade in South Asia.…”

Section: Discussionmentioning

confidence: 99%

Vibrio cholerae circulating throughout a mass vaccination campaign in the Forcibly Displaced Myanmar National population in Cox’s Bazar, Bangladesh

Taylor-Brown

Afrad

Khan

et al. 2022

Preprint

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Over the last decade, the influx of Forcibly Displaced Myanmar Nationals (FDMNs) into Bangladesh has increased the population of Cox’s Bazar. Due to the already high population density coupled with poor living conditions, FDMNs and the host population of Bangladeshi Nationals (BGDNs) were at heightened risk of diarrhoeal disease outbreaks. Due to this, a nationwide sentinel surveillance programme was established, which revealed that there were seasonal localised sporadic cholera outbreaks in Cox’s Bazar. In this study, we aimed to infer the epidemic risk of the Vibrio cholerae strains circulating in the FDMN and BGDN populations, by determining if isolates linked to the current cholera pandemic were responsible for these outbreaks. Further, to better understand the dynamics of cholera before and during the mass oral cholera vaccination campaign conducted in Cox’s Bazar – the largest in the last decades – we also wanted to understand the links between these circulating strains and the current radiation of lineages causing disease in Haiti and Yemen – places in which reactive vaccination campaigns were conducted in response to outbreaks following humanitarian crises. To do this, we sequenced 223 V. cholerae isolates obtained from stool collected from ten intra-district surveillance sites in Cox’s Bazar, sampling both the FDMN and BGDN subpopulations over a period spanning the pre-and post-vaccination campaign (2014–2019). Phylogenetic analysis of these genomes showed that all isolates belonged to the epidemic “7PET” lineage – responsible for the current cholera pandemic – branching alongside V. cholerae that were circulating in Dhaka and Kolkata between 2014 and 2018. Two distinct sublineages of V. cholerae were present in Cox’s Bazar during the study period; one lineage (PG 1.3) that had radiated globally, and another lineage (PG 1.5) that was restricted to Asia and the Middle East. PG 1.3 was associated with a shorter duration of diarrhoea and lower relative risk of rice watery stool compared to PG 1.5. Given the nature and diversity of the V. cholerae isolated from the BGDN and FDMN subpopulations in Cox’s Bazar, without a vaccine intervention, the risk of local or widespread epidemics or even a pandemic was very high.

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“…Whilst there were no known active cholera outbreaks in the Rakhine state at the time of the population displacement, the South Asian region is endemic for cholera 10 , 35 , and hence these strains may have also originated from Myanmar. Notably, Myanmar experienced higher than normal rates of diarrheal disease in 2012 and 2013, and 23% and 14% of tested severe diarrheal cases were determined to be V. cholerae O1 36 . Molecular analysis showed that 34 isolates carried the classical ctxB type ( ctxB 1), suggesting the strains present in 2012 and 2013 may have belonged to Clade 5, which would fit with the dominance of this clade in South Asia.…”

Section: Discussionmentioning

confidence: 99%

Genomic epidemiology of Vibrio cholerae during a mass vaccination campaign of displaced communities in Bangladesh

et al. 2023

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Ongoing diarrheal disease surveillance throughout Bangladesh over the last decade has revealed seasonal localised cholera outbreaks in Cox’s Bazar, where both Bangladeshi Nationals and Forcibly Displaced Myanmar Nationals (FDMNs) reside in densely populated settlements. FDMNs were recently targeted for the largest cholera vaccination campaign in decades. We aimed to infer the epidemic risk of circulating Vibrio cholerae strains by determining if isolates linked to the ongoing global cholera pandemic (“7PET” lineage) were responsible for outbreaks in Cox’s Bazar. We found two sublineages of 7PET in this setting during the study period; one with global distribution, and a second lineage restricted to Asia and the Middle East. These subclades were associated with different disease patterns that could be partially explained by genomic differences. Here we show that as the pandemic V. cholerae lineage circulates in this vulnerable population, without a vaccine intervention, the risk of an epidemic was very high.

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Cholera in Yangon, Myanmar, 2012–2013

Cited by 5 publications

References 9 publications

Molecular Epidemiology of Cholera Outbreaks during the Rainy Season in Mandalay, Myanmar

Molecular Epidemiology of Cholera Outbreaks during the Rainy Season in Mandalay, Myanmar

Vibrio cholerae circulating throughout a mass vaccination campaign in the Forcibly Displaced Myanmar National population in Cox’s Bazar, Bangladesh

Genomic epidemiology of Vibrio cholerae during a mass vaccination campaign of displaced communities in Bangladesh

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