Introduction

Diseases that are spread by contaminated food or water are covered in this section. Here you will find cholera and typhoid.

Cholera

Causative Agent

The bacterium Vibrio cholerae

Primary Host

Exclusively a human disease

Spread by

Faecal contamination. Commonly this is by contamination of water supplies or food. Human to human transmission is possible, but rare. Sudden large outbreaks are almost always traceable to contaminated water.

Fatality Rate

Up to 50%.

Birthplace

The Ganges Delta

Endemic Today

Most of Asia, Africa and South America

Earliest Known

Possibly reported earlier by Portuguese explorers, cholera was first positively identified in British India at the start of the nineteenth century. Large troop movements in 1817-18 spread it far beyond its normal range.

First Significant in Europe

The winter of 1831-32. It had spread rapidly to Europe by ship and rail.

Control Measures

Good sanitation and safe water supplies are the primary methods of control.

Situation Today

The world is currently in the grip of the seventh pandemic of cholera, which began in Indonesia in 1961. The bacterium responsible for this pandemic is considered to be relatively mild. Death is caused by the dehydration that results from severe diarrhoea and oral rehydration is a satisfactory treatment in the majority of cases. Antibiotics can be used to reduce the severity of disease, but some drug resistance has been noted. Oral vaccines can give effective, if short-term, protection to travellers.

Top of Page

Typhoid

Causative Agent

Salmonella typhi

Salmonella enteritidis paratyphi A, B and C cause the similar, but less severe, paratyphoid diseases.

Primary Host

Exclusively a human disease

Spread by

Faecal contamination. Commonly this is by contamination of water supplies but it may also be transmitted from improperly washed hands directly to other humans or to food. Flies may also transmit the disease to food. Carriers, the best known probably being Typhoid Mary, can transmit the disease to others, while remaining unaffected themselves.

Fatality Rate

Around 10% for untreated typhoid. Paratyphoid and treated typhoid fatality rates are much lower.

Endemic Today

The disease has been virtually eliminated from the industrialised countries, but is endemic through much of the rest of the world

Earliest Known

It has probably been present in human populations since the earliest settlements.

First Significant in Europe

The symptoms are non-specific, which makes its identification in history very difficult. It is, however, known to have been widespread in Europe no later than the eighteenth century. Sir William Jenner clearly delineated it from typhus in the nineteenth century.

Control Measures

Good sanitation and safe water supplies are the primary methods of control.

Situation Today

The disease causes around 17 million cases and 600,000 deaths per annum worldwide. Drug resistant varieties are known in many areas and multi-drug resistant varieties have been reported in Asia, the Middle East and Latin America. Immunization provides good protection to travellers.

Top of Page