Study of pathogenicity, mode of transmission and control measures of
Typhoid / Cholera
❖ Typhoid
Typhoid is a life-threatening bacterial infection that affects the intestines and sometimes
the bloodstream. It's caused by the Salmonella Typhi bacteria, which can be spread through
contaminated food or water. The disease continues to be a public health problem in many
developing areas of the WHO African, Eastern Mediterranean, South-East Asia and Western
Pacific Regions. As of 2019 estimates, there are 9 million cases of typhoid fever annually,
resulting in about 110 000 deaths per year. Typhoid risk is higher in populations that lack access
to safe water and adequate sanitation, and children are at highest risk.
Pathogenicity
TF fever is mainly caused by Salmonella typhi. After S. typhi has been ingested, it
reaches the intestinal epithelium, where it colonizes macrophages and dendritic cells in the
lamina propria; however, these fail to destroy the bacterium. Subsequently, bacteria invade the
bloodstream, multiply and spread to the lymph nodes, spleen and liver, causing multi-systemic
disease.
Isolation of S. typhi from blood is the most common method of diagnosis, though the
bacterium can also be isolated from bone marrow, faeces and duodenal fluid. Blood culture
displays suboptimal sensitivity, generally being positive in only about 50% of cases.
Causes
• Poor sanitation.
• Lack of clean drinking water.
• Eating food or drinking water contaminated with infected faeces or urine.
• Eating food that has been rinsed in contaminated water.
Symptoms
Prolonged fever, Headache, Nausea, Loss of appetite, Constipation or diarrhoea,
Abdominal pain, Dry cough, Fatigue, Sore throat.
Typhoid / Cholera
❖ Typhoid
Typhoid is a life-threatening bacterial infection that affects the intestines and sometimes
the bloodstream. It's caused by the Salmonella Typhi bacteria, which can be spread through
contaminated food or water. The disease continues to be a public health problem in many
developing areas of the WHO African, Eastern Mediterranean, South-East Asia and Western
Pacific Regions. As of 2019 estimates, there are 9 million cases of typhoid fever annually,
resulting in about 110 000 deaths per year. Typhoid risk is higher in populations that lack access
to safe water and adequate sanitation, and children are at highest risk.
Pathogenicity
TF fever is mainly caused by Salmonella typhi. After S. typhi has been ingested, it
reaches the intestinal epithelium, where it colonizes macrophages and dendritic cells in the
lamina propria; however, these fail to destroy the bacterium. Subsequently, bacteria invade the
bloodstream, multiply and spread to the lymph nodes, spleen and liver, causing multi-systemic
disease.
Isolation of S. typhi from blood is the most common method of diagnosis, though the
bacterium can also be isolated from bone marrow, faeces and duodenal fluid. Blood culture
displays suboptimal sensitivity, generally being positive in only about 50% of cases.
Causes
• Poor sanitation.
• Lack of clean drinking water.
• Eating food or drinking water contaminated with infected faeces or urine.
• Eating food that has been rinsed in contaminated water.
Symptoms
Prolonged fever, Headache, Nausea, Loss of appetite, Constipation or diarrhoea,
Abdominal pain, Dry cough, Fatigue, Sore throat.
