Typhoid Fever, also known as enteric fever, Salmonella typhi or commonly just typhoid, is an illness caused by the bacterium Salmonella enterica serovar typhi. Common worldwide, it is transmitted by the ingestion of food or water contaminated with feces from an infected person. The bacteria then perforate through the intestinal wall and are phagocytosed by macrophages. Salmonella typhi then alters its structure to resist destruction and allow them to exist within the macrophage. This renders them resistant to damage by PMN's, complement and the immune response. The organism is then spread via the lymphatics while inside the macrophages. This gives them access to the reticuloendothelial system and then to the different organs throughout the body. The organism is a Gram-negative short bacillus that is motile due to its peritrichous flagella. The bacteria grows best at 37 °C/99 °F – human body temperature.
Symptoms:
Typhoid fever is characterized by a sustained fever as high as 40 °C (104 °F), profuse sweating, gastroenteritis, and non bloody diarrhea. Less commonly a rash of flat, rose-colored spots may appear. Classically, the course of untreated typhoid fever is divided into four individual stages, each lasting approximately one week. In the first week, there is a slowly rising temperature with relative bradycardia, malaise, headache and cough. A bloody nose (epistaxis) is seen in a quarter of cases and abdominal pain is also possible. There is leukopenia, a decrease in the number of circulating white blood cells, with eosinopenia and relative lymphocytosis, a positive diazo reaction and blood cultures are positive for Salmonella typhi or paratyphi. The classic Widal test is negative in the first week.
In the second week of the infection, the patient lies prostrated with high fever in plateau around 40 °C (104 °F) and bradycardia (Sphygmo-thermic dissociation), classically with a dicrotic pulse wave. Delirium is frequent, frequently calm, but sometimes agitated. This delirium gives to typhoid the nickname of "nervous fever". Rose spots appear on the lower chest and abdomen in around 1/3 patients. There are rhonchi in lung bases. The abdomen is distended and painful in the right lower quadrant where borborygmi can be heard. Diarrhea can occur in this stage: six to eight stools in a day, green with a characteristic smell, comparable to pea-soup. However, constipation is also frequent. The spleen and liver are enlarged (hepatosplenomegaly) and tender and there is elevation of liver transaminases. The Widal reaction is strongly positive with antiO and antiH antibodies. Blood cultures are sometimes still positive at this stage. (The major symptom of this fever is the fever usually rises in the afternoon up to the first and second week.)
In the third week of typhoid fever a number of complications can occur:
• Intestinal hemorrhage due to bleeding in congested Peyer's patches; this can be very serious but is usually non-fatal.
• Intestinal perforation in distal ileum: this is a very serious complication and is frequently fatal. It may occur without alarming symptoms until septicaemia or diffuse peritonitis sets in.
• Encephalitis
• Metastatic abscesses, cholecystitis, endocarditis and osteitis
The fever is still very high and oscillates very little over 24 hours. Dehydration ensues and the patient is delirious (typhoid state). By the end of third week the fever has started reducing (defervescence). This carries on into the fourth and final week.
Epedemiology:
With an estimated 16-33 million cases of annually resulting in 500,000 to 600,000 deaths in endemic areas, the World Health Organization identifies typhoid as a serious public health problem. Its incidence is highest in children and young adults between 5 and 19 years old.
History:
Around 430–426 B.C., a devastating plague, which some believe to have been typhoid fever, killed one third of the population of Athens, including their leader Pericles. The balance of power shifted from Athens to Sparta, ending the Golden Age of Pericles that had marked Athenian dominance in the ancient world. Ancient historian Thucydides also contracted the disease, but he survived to write about the plague. His writings are the primary source on this outbreak. The cause of the plague has long been disputed, with modern academics and medical scientists considering epidemic typhus the most likely cause. However, a 2006 study detected DNA sequences similar to those of the bacterium responsible for typhoid fever. Other scientists have disputed the findings, citing serious methodologic flaws in the dental pulp-derived DNA study. The disease is most commonly transmitted through poor hygiene habits and public sanitation conditions; during the period in question, the whole population of Attica was besieged within the Long Walls and lived in tents.
This fever received various names, such as gastric fever, abdominal typhus, infantile remittent fever, slow fever, nervous fever, pythogenic fever, etc. The name of " typhoid " was given by Louis in 1829, as a derivative from typhus.
Mary Mallon ("Typhoid Mary") in a hospital bed. She was forcibly quarantined as a carrier of typhoid fever in 1907 for three years and then again from 1915 until her death in 1938.
In the late 19th century, typhoid fever mortality rate in Chicago averaged 65 per 100,000 people a year. The worst year was 1891, when the typhoid death rate was 174 per 100,000 persons. The most notorious carrier of typhoid fever—but by no means the most destructive—was Mary Mallon, also known as Typhoid Mary. In 1907, she became the first American carrier to be identified and traced. She was a cook in New York; some believe she was the source of infection for several hundred people. She is closely associated with forty-seven cases and three deaths. Public health authorities told Mary to give up working as a cook or have her gall bladder removed. Mary quit her job but returned later under a false name. She was detained and quarantined after another typhoid outbreak. She died of pneumonia after 26 years in quarantine.
In 1897, Almroth Edward Wright developed an effective vaccine. In 1909, Frederick F. Russell, a U.S. Army physician, developed an American typhoid vaccine and two years later his vaccination program became the first in which an entire army was immunized. It eliminated typhoid as a significant cause of morbidity and mortality in the U.S. military.
Most developed countries saw declining rates of typhoid fever throughout the first half of the 20th century due to vaccinations and advances in public sanitation and hygiene. Antibiotics were introduced in clinical practice in 1942, greatly reducing mortality. Today, incidence of typhoid fever in developed countries is around 5 cases per 1,000,000 people per year.
An outbreak in the Democratic Republic of Congo in 2004-05 recorded more than 42,000 cases and 214 deaths.
The Etiology Of Typhoid Fever:
Is typhoid fever due to a specific, well-defined, easily differentiated micro-organism, or are there several varieties of this germ, differing from one another in cultural, tinctorial, and possibly other properties? For many years after the discovery of the Eberth bacillus bacteriologists generally held that the micro-organism causing typhoid fever constitutes a distinct, easily recognizable species. In this country, at least, the writer stood almost or quite alone in claiming that there are varieties of this germ. In 1892 in a paper read before the Association of American Physicians, and published in the transactions of that Society, I made the following statement: "It probably makes but little difference whether we conclude that these germs are varieties of one species or that they are related species. I know of no hard and fast lines upon which one can decide, to the satisfaction of everyone else, whether two or more.
(Research Study)
