Super-strong cholera bacteria are all from Asia

Recent research shows that large cholera outbreaks are caused by bacteria originating in Asia, opening up hope to control the disease globally.

In 1854, British physicist John Snow made a map of cholera cases in London and found the main source of disease was a water pump on Broad Street. The London government removed the pump and helped prevent cholera from spreading further.

Recently, scientists carried out research similar to the global level and used advanced techniques of the 21st century.

By statistics and comparing hundreds of cholera bacteria genomes, they found that all the large cholera outbreaks in Africa or America half a century ago were all derived from the strange bacteria. chemistry from Asia.

A 3-year-old child with cholera during the epidemic in Peru in 1991 - (Photo: AP).

Starting from one place

Cholera caused by vibro cholera is often present in dirty water. For centuries, cholera bacteria seem to move from Asia to the rest of the world through water.

In the 1970s, Rita Colwell from the University of Maryland (USA) said that outbreaks of cholera originated in the local environment. She demonstrated that vibro cholera lives in many rivers and water sources near the sea.

Cholera bacteria associated with plankton. Climate events such as El Nino occur that increase the number of plankton that contribute to the outbreak of cholera in areas with poor sanitation. Therefore, Colwell warned that global climate change could make large cholera outbreaks occur more often.

From here, scientists argue that whether large cholera outbreaks are caused by local causes or external factors. There are also some who propose to combine the two hypotheses together.

"For example, Africa has about 12 outbreaks of large cholera in the past 50 years and may stem from a type of cholera vibro in Asia, then develop itself in accordance with the African environment , " Macro Salemi - molecular epidemiologist at the University of Florida (USA) said.

"However, these transcontinental bacteria can mutate genes with native species to create new strains. Therefore it is difficult to study," said Nicholas Thomson, a researcher at the Institute of Wellcome Trust Sanger (UK). .

To solve this problem, Thomson and the international team spent years gathering 714 cholera bacteria that developed over the past half century in Asia, Africa and the Americas. They compared and sequenced the genomes of hundreds of species in combination with analyzing results from previous studies.

Bacterial process described in America in the last 2 major outbreaks - (Photo: Science).

Thomson found that the Americas had two major cholera outbreaks in the past half century: an outbreak in Peru later spread to Latin American countries in 1991-1993 and another in Haiti in 2010.

Scientists give evidence that the cholera epidemic in Haiti by UN peacekeepers from Nepal unintentionally brought bacteria into the country. Meanwhile, the cholera outbreak began in the early 1990s by two lines: one to Africa directly to Peru, one from South Asia to Mexico and possibly "transiting" in Eastern Europe. It all comes from Asia.

In Africa, scientists pointed out that 11 special cholera bacteria of Asian origin have caused major epidemics. Local species are also dangerous but cannot cause major outbreaks.

Global cholera control opportunity

Children are vaccinated against cholera - (Photo: AsianScientist).

The study, published in the journal Science, may help end the long debate about the role of environmental factors with global cholera. Research can also help community health professionals focus resources on more dangerous cholera bacteria.

Accordingly, when a cholera case is detected, researchers can study whether the bacterium belongs to the "genealogy" of Asia, thereby predicting whether there will be a large cholera outbreak to host. use of limited capital resources.

At the same time, the study also points out the importance of eliminating the natural sources of disease here as the Asian cholera vibro.

"If we want to control cholera globally, we must first control in Asia, " said Dominique Legros, a cholera expert from the World Health Organization (WHO).

"There must be a special point in this continent that is suitable for the growth and spread of bacteria. Certainly the ecosystem there must be different from the other places," Thomson said.