Eng / Cholera_2023
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Choleragen
CTX is responsible for the massive, watery diarrhea characteristic of cholera infection
0139 (Bengal)
Two serogroups called O1 and O139 are responsible for cholera outbreaks.
However, not all infections with toxigenic Vibrio cholerae O1 or O139 will cause severe disease, and some cases may have uncomplicated corse
Reservoir of infection
It is sick person or vibrio carrier
The patient is most dangerous in the first days of illness.
Isolation of the pathogen persists until the 3rd week of illness
Carriage of the pathogen can lasts up to 1 year or more.
Reservoir of infection
Why cholera takes root in certain territories?
Cholera bacteria have been found in shellfish and plankton
Transmission is usually through the fecal-oral route of contaminated food or water caused by poor sanitation.
Most cholera cases in developed countries are a result of transmission by food, while in developing countries it is more often water.
Food transmission can occur when people harvest seafood such as oysters in waters infected with sewage, as Vibrio cholerae accumulates in planktonic crustaceans and the oysters.
India
The city of Kolkata has been described as the
"homeland of cholera", with regular outbreaks.
In India, where the disease is endemic, cholera outbreaks occur every year between dry seasons and rainy seasons.
Cholera outbreaks is mainly associated by high population density, unsafe drinking water, open drains, and poor sanitation which provide an optimal niche for survival and transmission of
Vibrio cholerae.
Ganges. Pilgrims at the temple
India, Brahmaputra river
Waterway transmission, activated during floods
Сholera pathogenesis
Most bacteria do not survive the acidic conditions of the human stomach.
In the small intestine they must propel themselves through the thick mucus to reach the intestinal walls where they can attach.
On the intestinal wall, V. cholerae start producing the toxic proteins - holerogen
.
Сholera pathogenesis
Cholera toxin (CTX or
CT) is an oligomeric complex consisting of one A and five B subunits.
The B subunits bind to the surface of intestinal epithelial cells.
Part of the A subunit binds to proteins and enters the cell.