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Typhoid fever, also known simply as typhoid, is a disease caused by Salmonella enterica serotype Typhi bacteria, also called Salmonella typhi. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several days. This is commonly accompanied by weakness, abdominal pain, constipation, headaches, and mild vomiting. Some people develop a skin rash with rose colored spots. In severe cases, people may experience confusion. Without treatment, symptoms may last weeks or months. Diarrhea may be severe, but is uncommon. Other people may carry it without being affected, but are still contagious. Typhoid fever is a type of enteric fever, along with paratyphoid fever. Salmonella enterica Typhi is believed to infect and replicate only within humans.
Salmonella is a genus of rod-shaped (bacillus) gram-negative bacteria of the family Enterobacteriaceae. The two known species of Salmonella are Salmonella enterica and Salmonella bongori. S. enterica is the type species and is further divided into six subspecies that include over 2,650 serotypes. Salmonella was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon.
Salmonella enterica is a rod-shaped, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus Salmonella. It is divided into six subspecies, arizonae (IIIa), diarizonae (IIIb), houtenae (IV), salamae (II), indica (VI), and enterica (I). A number of its serovars are serious human pathogens; many of them are serovars of Salmonella enterica subsp. enterica.
Salmonellosis is a symptomatic infection caused by bacteria of the Salmonella type. It is the most common disease to be known as food poisoning, these are defined as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. In humans, the most common symptoms are diarrhea, fever, abdominal cramps, and vomiting. Symptoms typically occur between 12 hours and 36 hours after exposure, and last from two to seven days. Occasionally more significant disease can result in dehydration. The old, young, and others with a weakened immune system are more likely to develop severe disease. Specific types of Salmonella can result in typhoid fever or paratyphoid fever. Typhoid fever and paratyphoid fever are specific types of salmonellosis, known collectively as enteric fever, and are, respectively, caused by salmonella typhi & paratyphi bacteria, which are only found in humans. Most commonly, salmonellosis cases arise from salmonella bacteria from animals, and chicken is a major source for these infections.
A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epidemiologic classification of organisms to a level below the species. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.
Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. It is associated with species of bacteria from the family Enterobacteriaceae. The term is usually restricted to Shigella infections.
Paratyphoid fever, also known simply as paratyphoid, is a bacterial infection caused by one of three types of Salmonella enterica. Symptoms usually begin 6–30 days after exposure and are the same as those of typhoid fever. Often, a gradual onset of a high fever occurs over several days. Weakness, loss of appetite, and headaches also commonly occur. Some people develop a skin rash with rose-colored spots. Without treatment, symptoms may last weeks or months. Other people may carry the bacteria without being affected; however, they are still able to spread the disease to others. Typhoid and paratyphoid are of similar severity. Paratyphoid and typhoid fever are types of enteric fever.
Rose spots are red macules 2-4 millimeters in diameter occurring in patients with enteric fever. These fevers occur following infection by Salmonella typhi and Salmonella paratyphi respectively. Rose spots may also occur following invasive non-typhoid salmonellosis.
The Vi capsular polysaccharide vaccine is a typhoid vaccine recommended by the World Health Organization for the prevention of typhoid. The vaccine was first licensed in the US in 1994 and is made from the purified Vi capsular polysaccharide from the Ty2 Salmonella Typhi strain; it is a subunit vaccine.
Ty21a is a live attenuated bacterial vaccine that protects against typhoid. First licensed in Europe in 1983 and in the United States in 1989, it is an orally administered, live-attenuated Ty2 strain of S. Typhi in which multiple genes, including the genes responsible for the production of Vi, have been deleted so as to render it harmless but nevertheless immunogenic. It is one of the three typhoid vaccines currently recommended by the World Health Organization.
The 2008 United States salmonellosis outbreak was an outbreak of salmonellosis across multiple U.S. states due to Salmonella enterica serovar Saintpaul. Over the course of the outbreak, 1442 cases were identified across 43 U.S. states, the District of Columbia, and Canada. The U.S. Centers for Disease Control and Prevention (CDC) investigation determined that jalapeño peppers imported from Mexico as well as Serrano peppers were major sources of the outbreak. Tomatoes may have been a source as well. The outbreak lasted from April to August 2008.
Salmonella enterica subsp. enterica is a subspecies of Salmonella enterica, the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the S. enterica species are in this subspecies, including that responsible for typhoid.
Phage typing is a phenotypic method that uses bacteriophages for detecting and identifying single strains of bacteria. Phages are viruses that infect bacteria and may lead to bacterial cell lysis. The bacterial strain is assigned a type based on its lysis pattern. Phage typing was used to trace the source of infectious outbreaks throughout the 1900s, but it has been replaced by genotypic methods such as whole genome sequencing for epidemiological characterization.
The 2012 outbreak of Salmonella took place in 15 places worldwide with over 2,300 strains identified.
Salmonella bongori is a pathogenic bacterium belonging to the genus Salmonella, and was earlier known as Salmonella subspecies V or S. enterica subsp. bongori or S. choleraesuis subsp. bongori. It is a Gram-negative, rod-shaped bacterium (bacillus), which causes a gastrointestinal disease called salmonellosis, characterized by cramping and diarrhoea. It is typically considered a microbe of cold-blooded animals, unlike other members of the genus, and is most frequently associated with reptiles.
Edward Thomas Ryan is an American microbiologist, immunologist, and physician at Harvard University and Massachusetts General Hospital. Ryan served as president of the American Society of Tropical Medicine and Hygiene from 2009 to 2010. Ryan is Professor of Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health, Professor of Medicine at Harvard Medical School, and Director of Global Infectious Diseases at the Massachusetts General Hospital. Ryan's research and clinical focus has been on infectious diseases associated with residing in, immigrating from, or traveling through resource-limited areas. Ryan is a Fellow of the American Society of Microbiology, the American Society of Tropical Medicine and Hygiene, the American College of Physicians, and the Infectious Diseases Society of America.
The Cocoliztli Epidemic or the Great Pestilence was an outbreak of a mysterious illness characterized by high fevers and bleeding which caused 5–15 million deaths in New Spain during the 16th century. The Aztec people called it cocoliztli, Nahuatl for pestilence. It ravaged the Mexican highlands in epidemic proportions, resulting in the demographic collapse of some Indigenous populations.
Arthur John Jex-Blake was a British physician, specializing in heart and lung diseases.
In 2000, typhoid fever caused an estimated 21.7 million illnesses and 217,000 deaths. It occurs most often in children and young adults between 5 and 19 years old. In 2013, it resulted in about 161,000 deaths – down from 181,000 in 1990. Infants, children, and adolescents in south-central and Southeast Asia experience the greatest burden of illness. Outbreaks of typhoid fever are also frequently reported from sub-Saharan Africa and countries in Southeast Asia. In the United States, about 400 cases occur each year, and 75% of these are acquired while traveling internationally.
Melita Alison Gordon is a gastroenterologist who works on invasive gut pathogens and tropical gastrointestinal disease. She leads the Malawi Liverpool Wellcome Trust Salmonella and Enterics Group. Gordon was awarded the British Society of Gastroenterology Sir Francis Avery Jones Research Medal in 2011.
References
- 1 2 3 Qamar, Farah Naz; Hussain, Wajid; Qureshi, Sonia (February 2022). "Salmonellosis Including Enteric Fever". Pediatric Clinics of North America . 69 (1): 65–77. doi:10.1016/j.pcl.2021.09.007. eISSN 1557-8240. ISSN 0031-3955. LCCN 54006097. OCLC 1643666. PMID 34794677.
- ↑ Hughes, Michael; Appiah, Grace; Watkins, Louise Francois (May 2023). "Typhoid & Paratyphoid Fever". CDC .
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