Q.78 Match the microorganisms to their predominant modes of transmission.
| Microorganism | Mode of Transmission |
|---|---|
| (i) Bordetella pertussis | (p) Vector-borne |
| (ii) Dengue virus | (q) Blood-borne |
| (iii) Entamoeba histolytica | (r) Droplet infection |
| (iv) Hepatitis B virus | (s) Contaminated food |
Options:
- (A) (i)-(q), (ii)-(p), (iii)-(s), (iv)-(q)
- (B) (i)-(s), (ii)-(q), (iii)-(p), (iv)-(r)
- (C) (i)-(r), (ii)-(q), (iii)-(p), (iv)-(s)
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The correct answer is option (C): (i)-(r), (ii)-(p), (iii)-(s), (iv)-(q).
Microorganism Transmissions
Bordetella pertussis spreads mainly through respiratory droplets from coughing or sneezing, matching droplet infection (r). Dengue virus transmits primarily via bites from infected Aedes mosquitoes, classifying it as vector-borne (p). Entamoeba histolytica passes through ingestion of cysts in contaminated food or water, aligning with contaminated food (s). Hepatitis B virus spreads predominantly through contact with infected blood or body fluids, such as via needles or sex, making it blood-borne (q).
Option Analysis
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Option (A): Wrong; Bordetella pertussis is droplet (r), not blood-borne (q); Dengue is vector-borne (p), correct; Entamoeba is contaminated food (s), correct; Hepatitis B is blood-borne (q), correct.
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Option (B): Wrong; Bordetella is droplet (r), not contaminated food (s); Dengue is vector-borne (p), not blood-borne (q); Entamoeba is contaminated food (s), not vector-borne (p); Hepatitis B is blood-borne (q), not droplet (r).
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Option (C): Correct; matches all: (i)-droplet (r), (ii)-vector (p), (iii)-food (s), (iv)-blood (q).
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Option (D): Wrong; Bordetella is droplet (r), not contaminated food (s); others mismatch.(D) (i)-(s), (ii)-(r), (iii)-(p), (iv)-(q)
Introduction to Microorganisms and Transmission Modes
Microorganisms like Bordetella pertussis, Dengue virus, Entamoeba histolytica, and Hepatitis B virus spread through specific predominant modes of transmission, crucial for CSIR NET Life Sciences preparation. Understanding droplet infection, vector-borne, contaminated food, and blood-borne routes prevents diseases and aids exam success. This guide solves matching question Q.78 with evidence-based details.
Bordetella pertussis: Droplet Infection
Bordetella pertussis causes whooping cough and transmits via aerosolized respiratory droplets during close contact coughing or sneezing. This droplet infection requires proximity, as the bacterium survives briefly in air. No vector or food involvement occurs predominantly.
Dengue Virus: Vector-Borne Transmission
Dengue virus relies on Aedes mosquitoes as vectors for predominant transmission through bites after an incubation period. Humans serve as reservoirs, but direct person-to-person spread is rare outside lab accidents. This distinguishes it from droplet or food routes.
Entamoeba histolytica: Contaminated Food Route
Entamoeba histolytica, causing amoebiasis, spreads mainly via fecal-oral route through cysts in contaminated food or water. Poor sanitation enables ingestion of infective cysts from feces-tainted sources. Vector or blood transmission plays no major role.
Hepatitis B Virus: Blood-Borne Spread
Hepatitis B virus transmits predominantly blood-borne through infected blood, semen, or body fluids via needles, sex, or perinatal exposure. While horizontal contact occurs, blood exposure defines its primary mode over droplets or vectors.
CSIR NET Exam Tips
Practice matching questions by recalling predominant modes: pertussis-droplet, Dengue-vector, amoeba-food, HBV-blood. Eliminate options systematically, as in Q.78 where (C) fits perfectly. Review CDC/WHO sources for accuracy in competitive exams.
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