HOME
        TheInfoList






The 1961–1975 cholera pandemic (also known as the seventh cholera pandemic) was the seventh major outbreak of cholera and occurred principally from the years 1961 to 1975; the strain involved persists to the present.[1] This pandemic, based on the strain called El Tor, started in Indonesia in 1961 and spread to Bangladesh by 1963.[2] Then it went to India in 1964, followed by the Soviet Union by 1966. In July 1970, there was an outbreak in Odessa and in 1972 there were reports of outbreaks in Baku, but the Soviet Union suppressed this information.[2] It reached Italy in 1973 from North Africa. Japan and the South Pacific saw a few outbreaks by the late 1970s.[2] In 1971, the number of cases reported worldwide was 155,000. In 1991, it reached 570,000.[1] The spread of the disease was helped by modern transportation and mass migrations. Mortality rates, however, dropped markedly as governments began modern curative and preventive measures. The usual mortality rate of 50% dropped to 10% by the 1980s and less than 3% by the 1990s.[1]

In 1991, the strain made a comeback in Latin America. It began in Peru, where it killed roughly 10,000 people.[3] Research has traced the origin of the strain to the seventh cholera pandemic.[4] It was suspected the strain came to Latin America through Asia from contaminated water, but samples from Latin America and samples from Africa were found to be identical.[5]

Introduction

Cholera is an acute diarrhoeal infection caused by the ingestion of food or water contaminated with the bacterium Vibrio cholera. Most commonly the contamination of food or water occurs via faecal matter, and the infection is spread through the faecal-oral route. Cholera has also been found to be caused by eating raw shellfish. Symptoms of the disease appear between 12 hours and 5 days of infection, however, only 10% of infected people show severe symptoms of watery diarrhoea, vomiting and leg cramps.[7] Cholera is diagnosed through a stool test or rectal swab and treatment takes the form of an oral rehydration solution (ORS). The ORS utilises equimolar concentrations of sodium and glucose to maximise sodium uptake in the small intestine, and carefully replaces fluid losses.[8] In severe cases, the rapid loss of bodily fluids leads to dehydration and patients are at risk of shock. This requires administration of intravenous fluids and antibiotics. The transmission of cholera is closely linked to inadequate access to clean water and sanitation facilities and hence, at risk areas are slums and poor communities.[9] The spread of cholera from 1961 to 1975 identify factors that played a role in the cholera pandemic. Terrorism, floods, improper sewage disposal and a lack of environmental hygiene were the main causes of the spread.

Sources

The history of the 7th pandemic can be traced to the beginning of 1961. The evolution of the classical cholera strain from the first 6 pandemics has been revealed through genetic analysis. The first observation of the new lineage comes from a laboratory in El Tor, Egypt, in 1897 and by this time, the ‘El Tor’ strain differed from its relatives by 30%.[10] It originated in South-Asia then transitioned to its non-pathogenic form in the Middle East in 1900. It was sometime between 1903 and 1908 that the El Tor strain picked up DNA that triggered its ability to cause disease in humans.[10] Hence, it had evolved into the El Tor pandemic strain.[11] Latin America. It began in Peru, where it killed roughly 10,000 people.[3] Research has traced the origin of the strain to the seventh cholera pandemic.[4] It was suspected the strain came to Latin America through Asia from contaminated water, but samples from Latin America and samples from Africa were found to be identical.[5]

This rapid transmission of the pathogen around the globe in the 20th century can be attributed to the major hub, the Bay of Bengal, the main place from which the disease spread. There have been six previous cholera pandemics. The seventh pandemic began in 1961 and is still occurring in 2020. Although the previous six pandemics were caused by the classical biotype of cholera, Vibrio cholerae, the El Tor lineage is the dominant strain in the seventh pandemic.

This pandemic can be categorized into two periods. During Period 1 (1961–1969), 24 Asian countries reported 419,968 cholera cases. In Period 2 (1970–1975), 73 countries from Asia, Africa, Europe and the Americas reported 706,261 cases.[6] Cholera is caused by eating food or drinking water that is contaminated with the bacteria V. cholerae. It affects both children and adults, causing severe watery This pandemic can be categorized into two periods. During Period 1 (1961–1969), 24 Asian countries reported 419,968 cholera cases. In Period 2 (1970–1975), 73 countries from Asia, Africa, Europe and the Americas reported 706,261 cases.[6] Cholera is caused by eating food or drinking water that is contaminated with the bacteria V. cholerae. It affects both children and adults, causing severe watery diarrhoea with dehydration.

Cholera is an acute diarrhoeal infection caused by the ingestion of food or water contaminated with the bacterium Vibrio cholera. Most commonly the contamination of food or water occurs via faecal matter, and the infection is spread through the faecal-oral route. Cholera has also been found to be caused by eating raw shellfish. Symptoms of the disease appear between 12 hours and 5 days of infection, however, only 10% of infected people show severe symptoms of watery diarrhoea, vomiting and leg cramps.[7] Cholera is diagnosed through a stool test or rectal swab and treatment takes the form of an oral rehydration solution (ORS). The ORS utilises equimolar concentrations of sodium and glucose to maximise sodium uptake in the small intestine, and carefully replaces fluid losses.[8] In severe cases, the rapid loss of bodily fluids leads to dehydration and patients are at risk of shock. This requires administration of intravenous fluids and antibiotics. The transmission of cholera is closely linked to inadequate access to clean water and sanitation facilities and hence, at risk areas are slums and poor communities.[9] The spread of cholera from 1961 to 1975 identify factors that played a role in the cholera pandemic. Terrorism, floods, improper sewage disposal and a lack of environmental hygiene were the main causes of the spread.

Sources

The history of the 7th pandemic can be traced to the beginning of 1961. The evolution of the classical cholera strain from the first 6 pandemics has been revealed through genetic analysis. The first observation of the new lineage comes from a laboratory in El Tor, Egypt, in 1897 and by this time, the ‘El Tor’ strain differed from its relatives by 30%.[10] It originated in South-Asia then transitioned to its non-pathogenic form in the Middle East in 1900. It was sometime between 1903 and 1908 that the El Tor strain picked up DNA that triggered its ability to cause disease in humans.[10] Hence, it had evolved into the El Tor pandemic strain.[11]The history of the 7th pandemic can be traced to the beginning of 1961. The evolution of the classical cholera strain from the first 6 pandemics has been revealed through genetic analysis. The first observation of the new lineage comes from a laboratory in El Tor, Egypt, in 1897 and by this time, the ‘El Tor’ strain differed from its relatives by 30%.[10] It originated in South-Asia then transitioned to its non-pathogenic form in the Middle East in 1900. It was sometime between 1903 and 1908 that the El Tor strain picked up DNA that triggered its ability to cause disease in humans.[10] Hence, it had evolved into the El Tor pandemic strain.[11] Makassar, Indonesia was the source of a 1960 outbreak of the El Tor strain, where it gained new genes that likely increased transmissibility.[10] Cholera then spread overseas in 1961, indicating a pandemic strain. Many studies point to Indonesia as the source of the 7th cholera pandemic, however research has indicated that outbreaks in China between 1960 and 1990 were associated with the same sub-lineages. These strains spread globally from the Bay of Bengal on multiple occasions.[12] This classifies China as both a sink and source during the pandemic spread of cholera throughout the 1960s and 1970s. This information that the pandemic spread of cholera may have been augmented by Chinese cases, in addition to China being named as an origin for bordering countries, contrasts with the view that the pandemic began in Indonesia, as many sources relay.

Spread and mortality