Intestinal infections

A 24-year-old male presents with continuous fever for 10 days, relative bradycardia, and rose spots on the abdomen.
Lab: Widal test: TO 1:320, TH 1:320; Blood culture: Salmonella Typhi isolated.
Question: What is the most likely stage of the disease?

Which disease may closely resemble typhoid fever during early stages but can be distinguished by relative lymphocytosis?
 

A 5-year-old child has fever, tenesmus, and bloody-mucous stools.
Stool microscopy: Many WBCs, RBCs, no protozoa.
Culture: Non-lactose fermenter on MacConkey, oxidase-negative.
Question: Which is the causative agent?
 

Which feature helps differentiate shigellosis from amoebic dysentery?
 

After eating raw eggs, several people develop nausea, vomiting, and diarrhea within 8 hours.
Stool culture: Salmonella enteritidis.
Question: What is the mechanism of infection?
 

A 30-year-old woman presents with diplopia, dysphagia, and descending paralysis after eating home-canned mushrooms.
Lab: Mouse bioassay positive for botulinum toxin.
Question: What is the key mechanism?
 

A 12-year-old child presents with jaundice, dark urine, elevated ALT/AST (>1000 IU/L).
Serology: Anti-HAV IgM positive.
Question: What does this indicate?
 

A patient’s lab results:
HBsAg (+), HBeAg (+), Anti-HBc IgM (+), ALT high.
Question: Interpretation?
 

ELISA anti-HCV positive, PCR HCV-RNA positive.
Question: What does this indicate?
 

A patient with acute hepatitis has both HBsAg and anti-HDV IgM.
Question: What is the correct interpretation?
 

A 26-year-old teacher presents with abrupt onset fever, myalgia, and dry cough.
Lab: Nasopharyngeal swab positive for Influenza A RNA.
Question: Best initial antiviral therapy?
 

A 2-year-old child presents with barking cough and inspiratory stridor.
X-ray: Steeple sign.
Diagnosis: Croup.
Question: Most probable etiologic agent?
 

A 45-year-old male with fever, cough, and loss of smell.
Lab: RT-PCR SARS-CoV-2 positive. CRP 60 mg/L, lymphopenia.
Question: Which marker correlates with severe disease?
 

ELISA test positive for HIV antibodies.
Question: Which confirmatory test is recommended?
 

A patient with recurrent oral candidiasis, CD4 = 180/μL.
Question: What is the stage of HIV infection?
 

A 34-year-old man with jaundice, ALT 800 IU/L, ALP 120 IU/L, bilirubin 150 μmol/L. No history of alcohol use.
Serology: HBsAg negative, anti-HAV IgM positive.
Question: Likely diagnosis?