Sidd
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"Sustainable dairy business."
Posted on 22. Dec 2023
Shigella is a species of enteric bacteria that causes disease in humans and other primates. Shigella is gram-negative rods that are non-motile and non-spore forming.The bacteria are primarily a human disease but has been found in some primates. Shigella are facultative anaerobes, similar to enterics such as E. coli (Brayan, Mckiley, & Mixon, 1971).Epidemiology
Shigella transmission can occur through direct person-to-person spread or from contaminated food and water. The minimal infectious dose can be transmitted directly from contaminated fingers, since intermediate bacterial replication is not required to achieve the low infectious dose.In developed countries, most cases are transmitted by faecal-oral spread from people with symptomatic infection. In developing countries, both faecal-oral spread and contamination of common food and water supplies are important mechanisms of transmission symptom.Pathogenesis
Shigella attaches to and penetrate intestinal cell walls of the small intestines by producing toxins that may promote the diarrhoea characteristic of the disease. The Shiga toxin enables the bacteria to penetrate the epithelial lining of the intestines, leading to a breakdown of the lining and haemorrhage.Shigella also have adhesins that promote binding to epithelial cell surfaces and invasion plasmid antigens that allow the bacteria to enter target cells, thus increasing its virulence (CDC, 2011).Symptoms
They include abdominal pain, cramps, diarrhoea, fever, vomiting, blood, pus or mucus in stools. Mild infections cause low-grade fever (38 - 38.9°C) and watery diarrhoea 1 to 2 days after people ingest the bacteria.Abdominal cramps and a frequent urge to defecate are common with more severe infections. Children, particularly young children, are most likely to have severe complications of high fever (41°C) sometimes with delirium. Severe dehydration with weigh loss is also a symptom.Detection of toxin
Shigella infection is diagnosed through testing of a stool sample. First a stool sample must be obtained from the potentially infected person, and then the sample is placed on a medium to encourage the growth of bacteria.If and when there is growth, the bacteria are identified, usually by looking at the growth under a microscope (Ibid).Control and prevention
Shigella is heat-sensitive and will be killed by thorough heating (over 70°C). Raw or undercooked foods and cross-contamination, when cooked material comes into contact with raw produce or contaminated materials (cutting boards), are the main causes of infection.Proper cooking and hygienic food handling thus can prevent Shigella infections to a large extend. There is currently no vaccine for Shigellosis prevention, but there is current research that appears promising.The most effective method for prevention is frequent and vigorous hand washing with warm, soapy water and ensuring clean drinking water sources and proper sewage disposal in developing nations (Malangu, 2016).Occurrence is worldwide and has higher prevalence in developing countries. Shigellosis is a major cause of diarrhoea in infants and children under the age of 5 years and accounts for 5-15% of diarrhoeal diseases cases seen at treatment centres.References
- Brayan, F., Mckiley, T., & Mixon, B. (1971). Use of Time Temperature in Detecting the Responsible Vehicles and Contributing Factors of Foodborne Disease Outbreaks. Journal of Milk Food Technology, 34, 576-582.
- CDC. (2011). Estimates of Foodborne Illnesses in the United States. New York: Centers of Disease Control.
- Malangu, N. (2016). Risk Factors and Outcomes of Food Poisoning in Africa. Intech Open.
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