Title 23. STUDY OF INFECTIOUS DISEASES.pdf ✅

PHARMD GURU Page 1 STUDY OF TYPHOID: The causative agent of typhoid is a bacteria, Salmonella typhi belonging to family Enterobacteriaceae. The bacteria is a gram negative, rod shaped bacteria in single arrangement. It has perichitous flagella for motility, it is non spore forming, facultative anaerobic, and capsular organism. VIRULENT FACTORS: The bacteria causes the infection due to the following virulent factors - H antigen present on the flagella, O antigen is a somatic antigen present on the body surface of the organism, Vi capsular antigen which Is a capsular producing antigen, endotoxin called lipopolysaccharlde, secretory protein called invasin which enters the non- phagocytic cells of the host. Due to these virulent factors the bacteria can escape from the host's immune mechanism. MECHANISM OF INFECTION: Salmonella typhi enters the host through the contaminated food and water, and from the stomach it enters into the Intestine. In the intestine it crosses the epithelium and reaches systemic circulation and enters into various tissues and organs. SIGNS AND SYMPTOMS:  In the first week of infection fluctuating bradycardia, malaise, headache, cough, and abdominal pain were observed.  In the second week of Infection high fever, bradycardia, delirium, rose colour spots on chest and trunk region, abdominal pain, diarrhoea or constipation are observed.  In the third week many complications like intestinal haemorrhage i.e., perforation mainly in the ileum region, where the organism enters the systemic circulation and cause various metastatic complications like abscesses in the liver, cholecystitis (inflammation of gall bladder), endocarditis (Inflammation of endocardium), osteitis and also oscillating type of fever usually high in afternoon, dehydration, delirium, and decrease in the platelet count leading to Internal bleeding. STUDY OF INFECTIOUS DISEASES
PHARMD GURU Page 2 DIAGNOSIS:  The diagnosis can be done by clinical symptoms, patient history, use of serological tests like Widal test in which the blood sample from the patient is taken and mixed with specific antibodies which react with H and O antigens of the bacteria present in the blood and forms antigen-antibody agglutination. It is a presumptive test.  Other confirmation tests are isolation test in which the cultures from the blood sample are isolated by using Macconkey’s agar/EMB agar media, and biochemical characterization (non lactose forming and non gas producing organism) are used.  The advanced techniques like PCR and blot tests are also used. MODE OF TRANSMISSION: The main source of transmission of typhoid is vomiting, fecal and urine disposals from the infected person. It may be transmitted directly or indirectly by carriers like flies. The transmission can be done by contaminated water and food, improper hygienic and sanitary conditions. IMMUNIZATION: The Immunization can be done by vaccination. The Vi capsular antigen vaccine or killed bacterial vaccine is given by parenteral route. The Immunity towards the Infection may be for only 2 — 3 years. PREVENTION AND CONTROL: The typhoid infection can be prevented by practicing proper sanitation and hygienic life style, careful food preparations, controlling flies, water purification, complete treatment for the infected persons, and educating the public about the disease. TREATMENT:  The first choice of the drug is fluoroquinolones e.g. ciprofloxacln and third generation cephalosporins e.g. ceftriaxone, cefotaxime, and cefixlme.  Other antibiotics used are ampicillin, chloramphenicol and combination of trimethoprim-sulfamethoxazole.  If complete drug therapy is not implemented, then the organism may get drug resistance and becomes difficult to remove the infection completely.