What is the main reservoir for Salmonella Typhi?
a) Rodents (rats).
b) Cattle.
c) Poultry.
d) Humans.
a) Rodents (rats).
b) Cattle.
c) Poultry.
d) Humans.
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For how long should a chronic food handler carrier be excluded from work?
a) Until symptoms resolve.
b) Until one negative stool culture is obtained.
c) Until three consecutive negative stool cultures, taken at least one month apart, are obtained.
d) They should be permanently banned
a) Until symptoms resolve.
b) Until one negative stool culture is obtained.
c) Until three consecutive negative stool cultures, taken at least one month apart, are obtained.
d) They should be permanently banned
Which statement about typhoid fever is FALSE?
a) Relapses can occur in a significant percentage of cases.
b) The Widal test is highly specific and sensitive.
c) Asymptomatic infections are common.
d) The causative organism is an intracellular bacteria.
a) Relapses can occur in a significant percentage of cases.
b) The Widal test is highly specific and sensitive.
c) Asymptomatic infections are common.
d) The causative organism is an intracellular bacteria.
Definition:
· A systemic illness caused by Salmonella bacteria.
· Typhoid Fever: Caused by Salmonella Typhi.
· Paratyphoid Fever: Caused by S. Paratyphi A & B, with milder symptoms.
· A systemic illness caused by Salmonella bacteria.
· Typhoid Fever: Caused by Salmonella Typhi.
· Paratyphoid Fever: Caused by S. Paratyphi A & B, with milder symptoms.
Clinical Picture:
· Insidious onset with sustained fever, severe headache, anorexia, relative bradycardia, and splenomegaly.
· A large proportion (60-90%) of cases are mild or asymptomatic, especially in endemic areas.
· Severe complications (bleeding/perforation) occur in about 1% of cases.
· Relapses are common (15-20% in typhoid).
· Insidious onset with sustained fever, severe headache, anorexia, relative bradycardia, and splenomegaly.
· A large proportion (60-90%) of cases are mild or asymptomatic, especially in endemic areas.
· Severe complications (bleeding/perforation) occur in about 1% of cases.
· Relapses are common (15-20% in typhoid).
Diagnosis:
· Gold Standard: Isolation of the bacteria via culture (best samples: blood in the first week, stool in the 2nd-3rd week, bone marrow even during antibiotic therapy).
· Widal Test: Has many limitations (false positives/negatives). A single test has little diagnostic value. Diagnostic if a four-fold rise in antibody titer is seen between acute and convalescent sera.
· Vi Antibody Test: Useful for screening chronic carriers.
· Newer serological tests (e.g., Typhidot, Tubex) offer better sensitivity and specificity than the Widal test.
· Gold Standard: Isolation of the bacteria via culture (best samples: blood in the first week, stool in the 2nd-3rd week, bone marrow even during antibiotic therapy).
· Widal Test: Has many limitations (false positives/negatives). A single test has little diagnostic value. Diagnostic if a four-fold rise in antibody titer is seen between acute and convalescent sera.
· Vi Antibody Test: Useful for screening chronic carriers.
· Newer serological tests (e.g., Typhidot, Tubex) offer better sensitivity and specificity than the Widal test.
Transmission
· Primarily fecal-oral route.
· Through ingestion of water or food contaminated with feces/urine from patients or carriers.
· Common sources: untreated water, raw vegetables fertilized with human waste, shellfish, unpasteurized milk.
· Primarily fecal-oral route.
· Through ingestion of water or food contaminated with feces/urine from patients or carriers.
· Common sources: untreated water, raw vegetables fertilized with human waste, shellfish, unpasteurized milk.
Reservoir & Carriers:
· Reservoir: Humans only (no animal reservoir).
· Convalescent Carrier: Excretes bacteria for 6-8 weeks.
· Chronic Carrier: (3% of infected individuals) excretes bacteria for >1 year. The bacteria persist in the gallbladder & biliary tract. Famous example: "Typhoid Mary".
· Reservoir: Humans only (no animal reservoir).
· Convalescent Carrier: Excretes bacteria for 6-8 weeks.
· Chronic Carrier: (3% of infected individuals) excretes bacteria for >1 year. The bacteria persist in the gallbladder & biliary tract. Famous example: "Typhoid Mary".
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Prevention & Control:
· Safe sanitation and clean water supply are fundamental.
· Exclude chronic carriers from food handling until 3 consecutive negative stool cultures are obtained.
· Typhoid Vaccines:
· Injectable Vi Polysaccharide Vaccine: (~75% efficacy), for ages ≥2 years.
· Oral Live Attenuated Ty21a Vaccine (Vivotif): (~90% efficacy for 3 years), for ages >6 years. Considered superior.
· Old TAB (killed) Vaccine: Not recommended by WHO; should be discontinued.
· Target Groups for Vaccination: Food handlers, travelers to endemic areas, school-aged children in endemic regions
· Safe sanitation and clean water supply are fundamental.
· Exclude chronic carriers from food handling until 3 consecutive negative stool cultures are obtained.
· Typhoid Vaccines:
· Injectable Vi Polysaccharide Vaccine: (~75% efficacy), for ages ≥2 years.
· Oral Live Attenuated Ty21a Vaccine (Vivotif): (~90% efficacy for 3 years), for ages >6 years. Considered superior.
· Old TAB (killed) Vaccine: Not recommended by WHO; should be discontinued.
· Target Groups for Vaccination: Food handlers, travelers to endemic areas, school-aged children in endemic regions
Treatment:
· Antibiotics: Ciprofloxacin, Ceftriaxone, Azithromycin.
· Chronic Carrier Treatment: Ciprofloxacin/Norfloxacin for 28 days (~80% success rate). May require cholecystectomy.
· Antibiotics: Ciprofloxacin, Ceftriaxone, Azithromycin.
· Chronic Carrier Treatment: Ciprofloxacin/Norfloxacin for 28 days (~80% success rate). May require cholecystectomy.
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Mid exam of 4th stage
Done ✅
الحمدلله حمداً كثيراً طيباً مباركاً فيه ❤️
Done ✅
الحمدلله حمداً كثيراً طيباً مباركاً فيه ❤️
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