Paratyphoid fever

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Paratyphoid fever
Other namesParatyphoid
Salmonella typhi typhoid fever PHIL 2215 lores.jpg
Rose colored spots on the chest of a person with typhoid fever which are similar to those of paratyphoid
Specialty Infectious disease
SymptomsFever, headache, rash, weakness [1] [2]
Usual onset6–30 days post exposure [1] [3]
DurationWeeks to months [1]
Causes Salmonella enterica spread by food or water contaminated with feces [1]
Risk factors Poor sanitation, crowded populations [4]
Diagnostic method Culturing the bacteria or detecting its DNA in the blood, stool, or bone marrow [1] [3]
PreventionHandwashing, clean water [1]
Treatment Antibiotics [1]
Frequency529,000 [5]
Deaths29,200 [6]

Paratyphoid fever, also known simply as paratyphoid, is a bacterial infection caused by one of the three types of Salmonella enterica . [1] Symptoms usually begin 6–30 days after exposure and are the same as those of typhoid fever. [1] [3] Often, a gradual onset of a high fever occurs over several days. [1] Weakness, loss of appetite, and headaches also commonly occur. [1] Some people develop a skin rash with rose-colored spots. [2] Without treatment, symptoms may last weeks or months. [1] Other people may carry the bacteria without being affected; however, they are still able to spread the disease to others. [3] Both typhoid and paratyphoid are of similar severity. [3] Paratyphoid and typhoid fever are types of enteric fever. [7]

Serotype infraspecific name

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 cell surface antigens, allowing the epidemiologic classification of organisms to the sub-species level. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.

<i>Salmonella enterica</i> subsp. <i>enterica</i> subspecies of bacterium

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.

Typhoid fever A bacterial infectious disorder contracted by consumption of food or drink contaminated with Salmonella typhi. This disorder is common in developing countries and can be treated with antibiotics.

Typhoid fever, also known simply as typhoid, is a bacterial infection due to Salmonella typhi that causes symptoms. Symptoms may vary from mild to severe and usually begin six to thirty days after exposure. Often there is a gradual onset of a high fever over several days; weakness, abdominal pain, constipation, headaches, and mild vomiting also commonly occur. Some people develop a skin rash with rose colored spots. In severe cases there may be confusion. Without treatment, symptoms may last weeks or months. Diarrhea is uncommon. Other people may carry the bacterium without being affected; however, they are still able to spread the disease to others. Typhoid fever is a type of enteric fever, along with paratyphoid fever.


Paratyphoid is caused by the bacterium Salmonella enterica of the serotypes Paratyphi A, Paratyphi B, or Paratyphi C growing in the intestines and blood. [1] They are usually spread by eating or drinking food or water contaminated with the feces of an infected person. [1] They may occur when a person who prepares food is infected. [2] Risk factors include poor sanitation as is found among poor crowded populations. [4] Occasionally, they may be transmitted by sex. [1] Humans are the only animals infected. [1] Diagnosis may be based on symptoms and confirmed by either culturing the bacteria or detecting the bacterial DNA in the blood, stool, or bone marrow. [1] [3] Culturing the bacteria can be difficult. [3] Bone-marrow testing is the most accurate. [4] Symptoms are similar to that of many other infectious diseases. [3] Typhus is an unrelated disease. [8]

Blood specialized bodily fluid in animals

Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.

Feces solid or semisolid remains of the food that could not be digested in the small intestine

Feces are the solid or semisolid remains of the food that could not be digested in the small intestine. Bacteria in the large intestine further break down the material. Feces contain a relatively small amount of metabolic waste products such as bacterially altered bilirubin, and the dead epithelial cells from the lining of the gut.

DNA Molecule that encodes the genetic instructions used in the development and functioning of all known organisms and many viruses

Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.

While no vaccine is available specifically for paratyphoid, the typhoid vaccine may provide some benefit. [1] [2] Prevention includes drinking clean water, better sanitation, and better handwashing. [1] Treatment of the disease is with antibiotics such as azithromycin. [1] Resistance to a number of other previously effective antibiotics is common. [1]

Vaccine biological preparatory medicine that improves immunity to a particular disease

A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future. Vaccines can be prophylactic, or therapeutic.

Typhoid vaccines are vaccines that prevent typhoid fever. Several types are widely available: typhoid conjugate vaccine (TCV), Ty21a and Vi capsular polysaccharide vaccine (ViPS). They are about 30 to 70% effective for the first two years depending on the specific vaccine in question. The Vi-rEPA vaccine has been shown to be efficacious in children.

Drinking water water safe for consumption

Drinking water, also known as potable water, is water that is safe to drink or to use for food preparation. The amount of drinking water required varies. It depends on physical activity, age, health issues, and environmental conditions. Americans, on average, drink one litre of water a day and 95% drink less than three litres per day. For those who work in a hot climate, up to 16 litres a day may be required. Water is essential for life.

Paratyphoid affects about six million people a year. [1] [9] It is most common in parts of Asia and rare in the developed world. [1] [2] Most cases are due to Paratyphi A rather than Paratyphi B or C. [3] In 2015, paratyphoid fever resulted in about 29,200 deaths, down from 63,000 deaths in 1990. [10] [6] The risk of death is between 10 and 15% without treatment, while with treatment, it may be less than 1%. [3]

Signs and symptoms

Rose spots on abdomen of a person with typhoid fever PHIL 2214.tif
Rose spots on abdomen of a person with typhoid fever

Paratyphoid fever resembles typhoid fever. Infection is characterized by a sustained fever, headache, abdominal pain, malaise, anorexia, a nonproductive cough (in early stage of illness), a relative bradycardia (slow heart rate), and hepatosplenomegaly (an enlargement of the liver and spleen). About 30% of Caucasians develop rosy spots on the central body. In adults, constipation is more common than diarrhea.

Bradycardia Heart rate that is below the normal range

Bradycardia is a condition typically defined wherein an individual has a resting heart rate of under 60 beats per minute (BPM) in adults. Bradycardia typically does not cause symptoms until the rate drops below 50 BPM. When symptomatic, it may cause fatigue, weakness, dizziness, sweating, and at very low rates, fainting.

Only 20 to 40% of people initially have abdominal pain. Nonspecific symptoms such as chills, sweating, headache, loss of appetite, cough, weakness, sore throat, dizziness, and muscle pains are frequently present before the onset of fever. Some very rare symptoms are psychosis (mental disorder), confusion, and seizures.


Paratyphoid fever is caused by any of three strains of Salmonella paratyphoid: S. Paratyphi A, S. schottmuelleri (also called S. Paratyphi B), or S. hirschfeldii (also called S. Paratyphi C).


They are usually spread by eating or drinking food or water contaminated with the feces of an infected person. [1] They may occur when a person who prepares food is infected. [2] Risk factors include poor sanitation as is found among poor crowded populations. [4] Occasionally, they may be transmitted by sex. Humans are the only animal infected. [1]

Paratyphoid B

Paratyphoid B is more frequent in Europe. It can present as a typhoid-like illness, as a severe gastroenteritis or with features of both. Herpes labialis, rare in true typhoid fever, is frequently seen in paratyphoid B. Diagnosis is with isolation of the agent in blood or stool and demonstration of antibodies antiBH in the Widal test. The disease responds well to chloramphenicol or co-trimoxazole.

Paratyphoid C

Paratyphoid C is a rare infection, generally seen in the Far East. It presents as a septicaemia with metastatic abscesses. Cholecystitis is possible in the course of the disease. Antibodies to paratyphoid C are not usually tested and the diagnosis is made with blood cultures. Chloramphenicol therapy is generally effective.


Humans and, occasionally, domestic animals are the carriers of paratyphoid fever. Members of the same family can be transient or permanent carriers. In most parts of the world, short-term fecal carriers are more common than urinary carriers. The chronic urinary carrier state occurs in those who have schistosomiasis (parasitic blood fluke).

Continuing to shed Salmonella Paratyphi is possible for up to one year, and during this phase, a person is considered to be a carrier. The chronic carrier state may follow acute illness, or mild or even subclinical infections. Chronic carriers are most often women who were infected in their middle age.


After ingestion, if the immune system is unable to stop the infection, the bacteria multiply and then spread to the bloodstream, after which the first signs of disease are observed in the form of fever. They penetrate further to the bone marrow, liver, and bile ducts, from which bacteria are excreted into the bowel contents. In the second phase of the disease, the bacteria penetrate the immune tissue of the small intestine, and the initial symptoms of small-bowel movements begin.


Providing basic sanitation and safe drinking water and food are the keys for controlling the disease. In developed countries, enteric fever rates decreased in the past when treatment of municipal water was introduced, human feces were excluded from food production, and pasteurization of dairy products began. [4] In addition, children and adults should be carefully educated about personal hygiene. This would include careful handwashing after defecation and sexual contact, before preparing or eating food, and especially the sanitary disposal of feces. Food handlers should be educated in personal hygiene prior to handling food or utensils and equipment. Infected individuals should be advised to avoid food preparation. Sexually active people should be educated about the risks of sexual practices that permit fecal-oral contact. [11]

Those who travel to countries with poor sanitation should receive a live attenuated typhoid vaccineTy21a (Vivotif), which, in addition to the protection against typhoid fever, may provide some protection against paratyphoid fever caused by the S. enterica serotypes A and B. [4] In particular, a reanalysis of data from a trial conducted in Chile showed the Ty21a vaccine was 49% effective (95% CI: 8–73%) in preventing paratyphoid fever caused by the serotype B. [12] Evidence from a study of international travelers in Israel also indicates the vaccine may prevent a fraction of infections by the serotype A, although no trial confirms this. [13] This cross-protection by a typhoid vaccine is most likely due to O antigens shared between different S. enterica serotypes. [13]

Exclusion from work and social activities should be considered for symptomatic, and asymptomatic people who are food handlers, healthcare/daycare staff who are involved in patient care and/or child care, children attending unsanitary daycare centers, and older children who are unable to implement good standards of personal hygiene. The exclusion applies until two consecutive stool specimens are taken from the infected patient and are reported negative.


Control requires treatment of antibiotics and vaccines prescribed by a doctor. Major control treatments for paratyphoid fever include ciprofloxacin for 10 days, ceftriaxone/cefotaxime for 14 days, or aziththromycin.


Those diagnosed with Type A of the bacterial strain rarely die from it except in rare cases of severe intestinal complications. With proper testing and diagnosis, the mortality rate falls to less than 1%. Antibiotics such as azithromycin are particularly effective in treating the disease. [14]


Factors outside the household, such as unclean food from street vendors and flooding, help distribute the disease from person to person. [11] Because of poverty and poor hygiene and insanitary conditions, the disease is more common in less-industrialized countries, principally owing to the problem of unsafe drinking water, inadequate sewage disposal, and flooding. [15] Occasionally causing epidemics, paratyphoid fever is found in large parts of Asia, Africa, and Central and South America. Many of those infected get the disease in Asian countries. About 16 million cases occur a year, which result in about 25,000 deaths worldwide. [16]

Related Research Articles

Shigellosis Human disease

Shigellosis is an infection of the intestines caused by Shigella bacteria. Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. The diarrhea may be bloody. Symptoms typically last five to seven days. Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome.

Whooping cough human disease caused by the bacteria Bordetella pertussis

Whooping cough is a highly contagious bacterial disease. Initially, symptoms are usually similar to those of the common cold with a runny nose, fever, and mild cough. This is followed by weeks of severe coughing fits. Following a fit of coughing, a high-pitched whoop sound or gasp may occur as the person breathes in. The coughing may last for 10 or more weeks, hence the phrase "100-day cough". A person may cough so hard that they vomit, break ribs, or become very tired from the effort. Children less than one year old may have little or no cough and instead have periods where they do not breathe. The time between infection and the onset of symptoms is usually seven to ten days. Disease may occur in those who have been vaccinated, but symptoms are typically milder.

Ascariasis A disease caused by the parasitic roundworm Ascaris lumbricoides

Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may include shortness of breath and fever in the beginning of the disease. These may be followed by symptoms of abdominal swelling, abdominal pain, and diarrhea. Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition, and learning problems.

Asymptomatic carrier pathogen carrier without symptoms

An asymptomatic carrier is a person or other organism that has become infected with a pathogen, but that displays no signs or symptoms.

Gastroenteritis Inflammation of the stomach and small intestine

Gastroenteritis, also known as infectious diarrhea, is inflammation of the gastrointestinal tract—the stomach and small intestine. Symptoms may include diarrhea, vomiting and abdominal pain. Fever, lack of energy and dehydration may also occur. This typically lasts less than two weeks. It is not related to influenza, though it has been called the "stomach flu".

Salmonellosis infection caused by Salmonella bacteria

Salmonellosis is a symptomatic infection caused by bacteria of the Salmonella type. 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.

Enterotoxigenic Escherichia coli (ETEC) is a type of Escherichia coli and one of the leading bacterial causes of diarrhea in the developing world, as well as the most common cause of travelers' diarrhea. Insufficient data exist, but conservative estimates suggest that each year, about 157,000 deaths occur, mostly in children, from ETEC. A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacteria are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells. The bacteria was identified by the Bradley Sack lab in Kolkata in 1968.

Meningococcal disease Human disease

Meningococcal disease describes infections caused by the bacterium Neisseria meningitidis. It has a high mortality rate if untreated but is vaccine-preventable. While best known as a cause of meningitis, it can also result in sepsis, which is an even more damaging and dangerous condition. Meningitis and meningococcemia are major causes of illness, death, and disability in both developed and under-developed countries.

Pneumococcal conjugate vaccine (PCV) is a pneumococcal vaccine and a conjugate vaccine used to protect infants, young children, and adults against disease caused by the bacterium Streptococcus pneumoniae. There are currently three types of PCV available on the global market, which go by the brand names: Prevnar, Synflorix and Prevnar 13.

An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the virus.

Mosquito-borne disease

Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. They can transmit disease without being affected themselves. Nearly 700 million people get a mosquito-borne illness each year resulting in over one million deaths.

In general, the United States alone experiences 1 million cases of salmonellosis per year. In Europe, although there are around 100,000 incidents of salmonellosis reported annually, there has been a steady decrease in cases over the past four years. The exact number of those infected is impossible to know as not all cases are reported. Of these reported cases, some can be classified as foodborne disease outbreaks by the Center for Disease Control and Prevention (CDC) if "two or more people get the same illness from the same contaminated food or drink" or zoonotic outbreaks if "two or more people get the same illness from the same pet or other animal". In 2012, the various strains or serotypes of the Salmonella bacteria, related to the outbreaks in the United States, infected over 1800 people and killed seven. In Europe, the European Centre for Disease Prevention and Control (ECDC) reported 91,034 cases of Salmonella infection with 65,317 cases related to the 2012 outbreaks. Of those 65,317 cases, there were 61 deaths.


A super-spreader is a host—an organism infected with a disease—that infects, disproportionately, more secondary contacts than other hosts who are, also, infected with the same disease. A sick human can be a super-spreader; they would be more likely to infect others than most people with the disease. Super-spreaders are thus of high concern in epidemiology.

Edward Thomas Ryan American bacteriologist and epidemiologist

Edward T. (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 2009-2010. 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.

Intestinal infectious diseases include a large number of infections of the bowels including: cholera, typhoid fever, paratyphoid fever, other types of salmonella infections, shigellosis, botulism, gastroenteritis, and amoebiasis among others.

This is a Timeline of typhoid fever, describing major events such as scientific/medical developments and notable epidemics.

Cocoliztli Epidemic of 1545–1548

Between 1545–1548 A.D., a mysterious illness, which was characterized by high fevers and bleeding, ravaged the Mexican highlands in epidemic proportions. The disease became known as Cocoliztli by the native Aztecs, and had devastating effects on the area’s demography, particularly for the indigenous people. Based on the death toll, this outbreak is often referred to as the worst disease epidemic in the history of Mexico Subsequent outbreaks continued to baffle both Spanish and native doctors, with little consensus among modern researchers on the pathogenesis. However, recent bacterial genomic studies have suggested that Salmonella, specifically a serotype of Salmonella enterica known as Paratyphi C, was at least partially responsible for this initial outbreak.


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