Cholera Practice Questions
20 free Cholera practice questions for the Microbiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
What is the primary causative agent of cholera?
- A Vibrio cholerae
- B Escherichia coli
- C Salmonella typhi
- D Shigella sonnei
Correct answer: Vibrio cholerae
Cholera is caused by Vibrio cholerae, a gram-negative, comma-shaped bacterium. It is transmitted through contaminated water and food sources.
Which toxin is responsible for the symptoms of cholera?
- A Endotoxin
- B Neurotoxin
- C Cholera toxin
- D Diphtheria toxin
Correct answer: Cholera toxin
Cholera toxin activates adenylate cyclase, increasing cAMP levels in intestinal cells. This leads to massive secretion of water and electrolytes into the intestinal lumen.
What is the typical appearance of stool in cholera patients?
- A Bloody stool
- B Rice-water stool
- C Black tarry stool
- D Mucus-rich stool
Correct answer: Rice-water stool
Cholera is characterized by 'rice-water stool,' which is pale, watery, and flecked with mucus. This reflects severe fluid loss without blood.
Which mode of transmission is most common for cholera?
- A Airborne droplets
- B Direct contact
- C Fecal-oral route
- D Vector-borne
Correct answer: Fecal-oral route
Cholera spreads primarily via the fecal-oral route through ingestion of contaminated water or food. Poor sanitation significantly increases transmission risk.
Which of the following is the most severe complication of cholera?
- A Sepsis
- B Dehydration
- C Liver failure
- D Pneumonia
Correct answer: Dehydration
Severe dehydration is the most dangerous complication of cholera due to rapid fluid loss. If untreated, it can lead to shock and death.
Which electrolyte imbalance is most commonly seen in cholera?
- A Hyperkalemia
- B Hyponatremia
- C Hypercalcemia
- D Hypomagnesemia
Correct answer: Hyponatremia
Cholera causes loss of sodium and water through diarrhea, leading to hyponatremia. This contributes to weakness and neurological symptoms.
What is the primary treatment for cholera?
- A Intravenous antibiotics
- B Oral rehydration therapy
- C Antimotility medication
- D Antitoxin administration
Correct answer: Oral rehydration therapy
Oral rehydration therapy (ORT) is the cornerstone of cholera treatment. It replaces lost fluids and electrolytes effectively and reduces mortality.
Which culture medium is commonly used to isolate Vibrio cholerae?
- A MacConkey agar
- B EMB agar
- C TCBS agar
- D Chocolate agar
Correct answer: TCBS agar
Thiosulfate-citrate-bile salts-sucrose (TCBS) agar is selective for Vibrio species. Vibrio cholerae produces yellow colonies due to sucrose fermentation.
What is the shape of Vibrio cholerae?
- A Cocci
- B Bacilli
- C Comma-shaped
- D Spiral-shaped
Correct answer: Comma-shaped
Vibrio cholerae is a curved, comma-shaped bacterium. This morphology helps distinguish it from other bacteria under the microscope.
Which serogroups of Vibrio cholerae are most commonly associated with epidemics?
- A O26 and O55
- B O157 and O111
- C O1 and O139
- D O2 and O5
Correct answer: O1 and O139
Serogroups O1 and O139 are responsible for most cholera outbreaks worldwide. They produce cholera toxin and cause epidemic disease.
Which environmental condition favors the growth of Vibrio cholerae?
- A Dry climate
- B Cold temperatures
- C Saline water
- D High altitude
Correct answer: Saline water
Vibrio cholerae thrives in brackish or saline water environments. It is commonly found in coastal and estuarine regions.
Which preventive measure is most effective against cholera?
- A Routine antibiotic prophylaxis
- B Clean water and sanitation
- C Mass vaccination campaigns
- D Mandatory quarantine measures
Correct answer: Clean water and sanitation
Ensuring clean water and proper sanitation is the most effective way to prevent cholera. It reduces fecal contamination and transmission risk in vulnerable communities.
Which of the following best describes cholera toxin mechanism?
- A Inhibits protein synthesis
- B Disrupts cell membrane integrity
- C Blocks DNA replication
- D Raises cAMP in intestinal cells
Correct answer: Raises cAMP in intestinal cells
Cholera toxin increases intracellular cAMP levels by activating adenylate cyclase. This leads to chloride and water secretion into the intestine.
Which antibiotic is sometimes used in severe cholera cases?
- A Metronidazole
- B Tetracycline
- C Vancomycin
- D Rifampicin
Correct answer: Tetracycline
Tetracycline and other antibiotics can reduce the duration and severity of cholera. However, rehydration remains the main treatment.
Which population is most at risk for severe cholera?
- A Immunocompromised individuals
- B Malnourished children under five
- C Elderly in crowded urban areas
- D People in poor sanitation areas
Correct answer: People in poor sanitation areas
People living in areas with poor sanitation and limited clean water are at higher risk. Outbreaks are common in such conditions.
What is the incubation period of cholera?
- A Fourteen to twenty days
- B One to two months
- C Three to six weeks
- D Few hours to 5 days
Correct answer: Few hours to 5 days
The incubation period of cholera ranges from a few hours to 5 days. Symptoms can develop rapidly after ingestion of contaminated food or water.
Which test is commonly used for rapid diagnosis of cholera in outbreaks?
- A Rapid dipstick test
- B Dark-field microscopy
- C Stool culture plating
- D Latex agglutination
Correct answer: Rapid dipstick test
Rapid dipstick tests can quickly detect Vibrio cholerae in stool samples. They are useful in field settings during outbreaks.
Which organ system is primarily affected in cholera?
- A Respiratory system
- B Nervous system
- C Cardiovascular system
- D Digestive system
Correct answer: Digestive system
Cholera primarily affects the gastrointestinal tract, especially the small intestine. It leads to profuse watery diarrhea.
What is the main virulence factor of Vibrio cholerae besides toxin production?
- A Biofilm matrix
- B Flagella
- C Spores
- D Adhesion pili
Correct answer: Adhesion pili
Vibrio cholerae uses toxin-coregulated pili (TCP) to adhere to intestinal cells. This colonization is essential for toxin delivery and disease progression.
Which global organization plays a major role in cholera control programs?
- A WHO
- B UNICEF
- C UNDP
- D FAO
Correct answer: WHO
The World Health Organization (WHO) coordinates global cholera control strategies. It supports vaccination, surveillance, and water sanitation initiatives.