Эндемичная холера в Индии и завозная холера в России: что общего?

Эндемичность холеры в Индии хорошо изучена. Среди ряда других эндемичных регионов Индийский субконтинент, по-видимому, является местом формирования нескольких вариантов холерных вибрионов, впоследствии распространившихся по всему миру. Напротив, в России все зарегистрированные случаи холеры имели завозное происхождение. В прошлом столетии такие завозы могли приводить к эпидемиям, которые заканчивались вместе с элиминацией токсигенных штаммов Vibrio cholerae (TVC) из пораженных регионов. В настоящее время выделение TVC как из водоемов, так и от возвратившихся из азиатских стран больных, является редкостью, в основном благодаря постоянному мониторингу и контролю. Кроме того, климатические условия большинства областей России неблагоприятны для длительного выживания возбудителя во внешней среде. Однако глобальные изменения климата, сопровождающиеся неожиданными аномалиями в ранее стабильных климатических зонах, могут способствовать распространению отдельных завозных TVC, что может привести к эпидосложнениям по холере. В некоторых регионах России сезонные погодные условия очень похожи на индийские. Молекулярные исследования штаммов из разных мест выделения показывают, что TVC распространились на новые территории и приобрели дополнительные свойства, отсутствующие у их недавних предшественников.
В настоящей работе описаны геномные характеристики TVC, выделенных в России, Индии и некоторых других странах. Обзор дополнен биоинформатическим анализом генетических маркеров, значимых для дифференциации клонов, появившихся в  эндемичных регионах и завезенных на территории, где холера прежде отсутствовала. Мы нашли добавочные свидетельства в пользу первичного индийского происхождения недавно возникших геновариантов и их продолжающейся трансформации, включая появление нового аллеля гена rtxA с делецией 60 п.н. в дополнение к ранее известной null-мутации. В определенных условиях TVC могут представлять потенциальную угрозу распространения эпидемической холеры в России и на других территориях. Борьба с  холерой требует совместных усилий исследователей, направленных на получение знаний о возбудителе на молекулярном уровне, в целях разработки эффективных стратегий защиты человечества во всем мире. 

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