![]() It is preferable to test two specimens of sera at an interval of 7 to 10 days to demonstrate a rising antibody titre.Salmonella antibody starts appearing in serum at the end of first week and rise sharply during the 3rd week of endemic fever. In acute typhoid fever, O agglutinins can usually be detected 6–8 days after the onset of fever and H agglutinins after 10–12 days.Paratyphi C H antigen suspension, c, phase 1 Paratyphi B H antigen suspension, b, phase 1 Paratyphi B 0 antigen suspension, 1, 4, 5, 12 Paratyphi A 0 antigen suspension, 1, 2, 12 The patient’s serum is tested for O and H antibodies (agglutinins) against the following antigen suspensions (usually stained suspensions):.It was developed by Georges Ferdinand Widal in 1896.When facilities for culturing are not available, the Widal test is the reliable and can be of value in the diagnosis of typhoid fevers in endemic areas.Widal Test is an agglutination test which detects the presence of serum agglutinins (H and O) in patients serum with typhoid and paratyphoid fever.Besides being in contact with contaminated water or food, occupations such as clinical microbiologist are also at a risk of developing typhoid and thus, should take necessary preventive measures. Vaccines are available, which are recommended to be taken in case of travel plans to areas prone to typhoid fever. Adequate hydration and adequate rest is recommended for the patient for a speedy recovery. Appropriate antibiotics along with supportive care generally help the patient. The treatment depends on the strain of bacteria that affects the person. Even after complete recovery, there may be reoccurrence in future or the affected individual may act as a carrier for a considerable period of time. Typhoid or enteric fever usually last for about 3 to 4 weeks with an incubation period of 1 – 2 weeks. The condition is associated with symptoms such as increase in body temperature (often up to 104 degree Fahrenheit) along with generalised weakness, fatigue, loss of appetite, lack of energy, and/or diarrhoea. These bacteria enter the human blood stream and begin to multiply. It is a contagious disease and it is usually caused by eating or drinking food or water contaminated by Salmonella bacteria. Salmonella typhi causes a serious condition called as Typhoid or enteric fever. Which Diseases are Caused by Salmonella Typhi? ![]() This helps us in understanding the severity and extent of the condition and thus helps us in rightful treatment planning. Antibodies produced in response to H antigens are generally present for a couple of months whereas the antibodies produced in response to O antigen generally reduce after 2 weeks of the disease. Antibodies produced in response to H antigen (or flagellar antigen) are noted during later stage of the disease and it reaches a peak during the third week of the disease. The presence of O and H antigen are clinically very significant as the antibodies produced in response to O antigen (or IgM) is noted in the early stages of the diseases and it reaches a peak level by the second week of the disease. It is a serological test, where the titre of antibodies produced in the patients serum (in response to O and H antigens found on the surface of the Salmonella bacteria) is measured by a process called as haemagglutiation. It was developed by Georges Ferdinand Widal in the year 1896. Widal test is a specific laboratory test, used for diagnosis of typhoid fever. The presence of these antigens and production of antibodies by the affected individual, due to the response of their immune system forms the basis of a diagnostic test called as Widal test. The flagella found on the surface of these bacteria helps in movement of the organism. ![]() The O antigen (also known as somatic antigen) is found on the cell wall of the bacteria, whereas the H antigen is produced in the flagellated portion. These antigens which are found on the cell surface of Salmonella are known as O and H antigens. Patients affected by typhoid fever produce antibodies against the antigens of Salmonella bacteria.
0 Comments
Leave a Reply. |