Bacterial Diseases

Q80. Which disease–category pairing is incorrect?

[UPSC CDS-I 2026, General Knowledge]

• (A) Polio — viral
• (B) Athlete’s foot — fungal
• (C) Dengue — non-viral
• (D) Whooping cough — bacterial

Answer: (C) Dengue — non-viral

Explanation: Dengue is caused by dengue viruses, so calling it non-viral is wrong. Whooping cough is caused by Bordetella pertussis; athlete’s foot is a fungal infection, while poliomyelitis is viral. The question tests accurate distinctions among infectious agents.

Q79. What was the 2025 World Leprosy Day theme?

[RRB NTPC (UG) CBT-I, 9 May 2026]

• (A) Beat Leprosy
• (B) Unite. Act. Eliminate.
• (C) Act Now. End Leprosy.
• (D) United for Dignity

Answer: (B) Unite. Act. Eliminate.

Explanation: The 2025 World Leprosy Day theme was “Unite. Act. Eliminate.” The observance promotes early detection, effective multidrug treatment and reduction of discrimination. Leprosy, or Hansen’s disease, is a curable bacterial disease associated chiefly with Mycobacterium leprae.

Q78. Identify the bacterial disease among these four conditions.

[DSSSB Assistant Superintendent, 5 July 2026]

• (A) Influenza
• (B) Typhoid
• (C) AIDS
• (D) Ringworm

Answer: (B) Typhoid

Explanation: Typhoid fever results from Salmonella Typhi infection and commonly spreads through contaminated food or water. Influenza and AIDS are viral conditions, whereas ringworm is caused by fungi. This distinction is frequently used in competitive examinations testing microbial classification.

Q77. Which term commonly describes a medicine used to kill or inhibit bacteria?

[DSSSB MTS, 27 July 2026]

• (A) Analgesic
• (B) Antibiotic
• (C) Sedative
• (D) Antacid

Answer: (B) Antibiotic

Explanation: Antibiotics act against susceptible bacteria by killing them or suppressing their growth. Analgesics relieve pain, sedatives produce calmness and antacids neutralise stomach acid. Antibiotics should be prescribed appropriately because misuse promotes antimicrobial resistance and can harm beneficial microbes.

Q76. Which disease is spread primarily through the air?

[UPSC CDS-II 2025, General Knowledge]

• (A) Tuberculosis
• (B) Malaria
• (C) Dengue
• (D) Cholera

Answer: (A) Tuberculosis

Explanation: Pulmonary tuberculosis spreads through inhalation of infectious airborne particles released by people with active lung or laryngeal TB. Malaria and dengue are mosquito-borne, while cholera spreads mainly through contaminated food or water. Ventilation helps reduce airborne TB transmission.

Q75. Which slogan was used for World Tuberculosis Day 2025?

[RRB Group D, 23 December 2025]

• (A) Yes! We Can End TB: Commit, Invest, Deliver
• (B) Unite to End TB: Fund, Innovate, Act
• (C) TB Free by 2030: Global Pact
• (D) End TB Now: Diagnose, Treat, Prevent

Answer: (A) Yes! We Can End TB: Commit, Invest, Deliver

Explanation: The 2025 campaign emphasised commitment, investment and delivery of services to end tuberculosis. World TB Day is observed on 24 March, the anniversary of Robert Koch’s 1882 announcement identifying the tuberculosis bacterium. Early diagnosis and effective treatment remain crucial.

Q74. Which disease did Puducherry target through screening under its Family Adoption Programme?

[RRB Group D, 12 December 2025]

• (A) Dengue
• (B) Diabetes
• (C) Malaria
• (D) Tuberculosis

Answer: (D) Tuberculosis

Explanation: The cited 2025 initiative focused on tuberculosis screening, consistent with India’s National Tuberculosis Elimination Programme. Screening seeks to detect infection and disease earlier, link affected people to proper testing and treatment, and reduce continued community transmission.

Q73. How many groups are traditionally described by the Ridley–Jopling leprosy classification?

[RRB Pharmacist, 28 April 2025]

• (A) Three
• (B) Six
• (C) Five
• (D) Seven

Answer: (C) Five

Explanation: The Ridley–Jopling spectrum comprises five principal groups: tuberculoid, borderline tuberculoid, mid-borderline, borderline lepromatous and lepromatous leprosy. The system reflects differences in host immunity and clinical presentation. An indeterminate early category is sometimes described separately.

Q72. DPT vaccination protects against which three diseases?

[RPF Constable (2024 cycle), 17 March 2025]

• (A) Diphtheria, pneumonia and tetanus
• (B) Diphtheria, pancreatitis and tetanus
• (C) Diphtheria, pertussis and tetanus
• (D) Diphtheria, polio and tetanus

Answer: (C) Diphtheria, pertussis and tetanus

Explanation: DPT combines protection against diphtheria, pertussis (whooping cough) and tetanus. All three are bacterial diseases, although tetanus is acquired from environmental spores rather than ordinary person-to-person spread. Immunisation markedly lowers disease risk and severe complications.

Q71. Which illness is especially associated with drinking untreated, faecally contaminated pond water?

[Punjab Police Constable, 30 May 2025]

• (A) Cholera
• (B) Scurvy
• (C) Beriberi
• (D) Iron-deficiency anaemia

Answer: (A) Cholera

Explanation: Cholera is caused by toxigenic Vibrio cholerae and is commonly acquired through contaminated water or food. Severe cases cause profuse watery diarrhoea and rapid dehydration. Safe water, sanitation and timely rehydration are the central public-health and clinical responses.

Q70. Select the group containing only bacterial infections.

[MAHA TET, 23 November 2025]

• (A) Cholera, typhoid and tuberculosis
• (B) Tetanus, tuberculosis and measles
• (C) Malaria, mumps and poliomyelitis
• (D) AIDS, malaria and influenza

Answer: (A) Cholera, typhoid and tuberculosis

Explanation: Vibrio cholerae causes cholera, Salmonella Typhi causes typhoid and Mycobacterium tuberculosis causes tuberculosis. Measles, mumps, polio, influenza and AIDS are viral conditions; malaria is protozoan. Identifying the causative organism prevents misleading treatment choices.

Q69. Which condition differs because it is non-infectious: typhoid, malaria, diabetes or cholera?

[SSC JE, 6 December 2025]

• (A) Typhoid
• (B) Malaria
• (C) Diabetes
• (D) Cholera

Answer: (C) Diabetes

Explanation: Diabetes mellitus is a metabolic disorder, not an infection transmitted between people. Typhoid and cholera are bacterial infections, while malaria is caused by Plasmodium parasites. Classification as infectious or non-infectious is separate from classifying pathogens by organism type.

Q68. Baba Amte is especially remembered for working with people affected by which disease?

[MP Police Constable, 6 December 2025]

• (A) Tuberculosis
• (B) Leprosy
• (C) Cholera
• (D) Typhoid

Answer: (B) Leprosy

Explanation: Baba Amte dedicated much of his social work to supporting people affected by leprosy and combating stigma. He established Anandwan in Maharashtra, promoting rehabilitation and dignity. Leprosy is caused mainly by Mycobacterium leprae and is treatable with multidrug therapy.

Q67. Choose the set in which all three diseases are bacterial.

[SSC CGL Tier-I, 17 September 2024]

• (A) Influenza, dengue, cholera
• (B) Typhoid, cholera, tuberculosis
• (C) Dengue, malaria, cholera
• (D) Malaria, common cold, influenza

Answer: (B) Typhoid, cholera, tuberculosis

Explanation: Typhoid, cholera and tuberculosis are caused by Salmonella Typhi, Vibrio cholerae and Mycobacterium tuberculosis respectively. Dengue, influenza and the common cold are viral; malaria is protozoan. Recognising each causative agent is a core biology competency.

Q66. Which communicable disease among the following is bacterial?

[SSC MTS, 15 October 2024]

• (A) Cholera
• (B) Malaria
• (C) Dengue
• (D) Influenza

Answer: (A) Cholera

Explanation: Cholera develops after infection by toxigenic Vibrio cholerae, frequently through contaminated drinking water. Malaria is caused by protozoa, while dengue and influenza are viral. Cholera control rests on clean water, appropriate sanitation, rapid fluid replacement and vaccination when indicated.

Q65. The Widal agglutination test is historically associated with which disease?

[SSC MTS, 22 October 2024]

• (A) Pneumonia
• (B) Typhoid
• (C) Diphtheria
• (D) Influenza

Answer: (B) Typhoid

Explanation: The Widal test measures antibodies reacting with Salmonella Typhi and Paratyphi antigens. It is historically associated with enteric fever but has important accuracy limitations; blood culture is preferred for confirming typhoid where feasible. Interpretation depends on illness timing and local background titres.

Q64. Which of these is caused by bacteria rather than viruses?

[RSMSSB Women Supervisor, 22 June 2024]

• (A) Hepatitis B
• (B) AIDS
• (C) COVID-19
• (D) Typhoid

Answer: (D) Typhoid

Explanation: Typhoid is caused by Salmonella Typhi, a bacterium transmitted mainly through the faecal–oral route. Hepatitis B, AIDS and COVID-19 have viral causes. Typhoid prevention combines improved water quality, food hygiene, sanitation and appropriate vaccination.

Q63. Which listed illness is ordinarily categorised as waterborne?

[WBPSC Miscellaneous (2023 cycle), 15 September 2024]

• (A) Tuberculosis
• (B) Typhoid
• (C) Malaria
• (D) Diphtheria

Answer: (B) Typhoid

Explanation: Typhoid commonly spreads when food or water is contaminated by faeces containing Salmonella Typhi. Pulmonary tuberculosis and diphtheria are primarily respiratory infections, while malaria requires an infected Anopheles mosquito. Safe water supplies reduce enteric fever transmission.

Q62. Which of these is not a waterborne infection?

[WBMSC Sub-Assistant Engineer, 4 August 2024]

• (A) Dysentery
• (B) Cholera
• (C) Typhoid
• (D) Malaria

Answer: (D) Malaria

Explanation: Malaria is caused by Plasmodium parasites transmitted by infected female Anopheles mosquitoes, not by drinking contaminated water. Cholera and typhoid commonly spread through contaminated food or water; dysentery may be caused by several pathogens with faecal–oral transmission.

Q61. Match typhoid, leishmaniasis, ringworm and filariasis with their causative agent types.

[NEET UG, 5 May 2024]

• (A) Fungus, protozoan, nematode, bacterium
• (B) Bacterium, protozoan, fungus, nematode
• (C) Protozoan, fungus, bacterium, nematode
• (D) Nematode, bacterium, protozoan, fungus

Answer: (B) Bacterium, protozoan, fungus, nematode

Explanation: Typhoid is bacterial; leishmaniasis results from protozoan Leishmania; ringworm is fungal; and lymphatic filariasis is produced by filarial nematodes. This classification highlights why outwardly similar infectious diseases can require entirely different prevention and treatment strategies.

Q60. A microorganism that actually produces disease is termed a what?

[UPPSC PCS Prelims 2024]

• (A) Archaeon
• (B) Pathogen
• (C) Bacterium, in every case
• (D) Protozoan, in every case

Answer: (B) Pathogen

Explanation: A pathogen is any disease-causing biological agent. Bacteria, viruses, fungi, protozoa and certain parasites can be pathogenic, but most microorganisms are not harmful. Therefore, pathogen describes disease-causing ability rather than a single taxonomic group of microbes.

Q59. Which sequence matches Alzheimer’s disease, diphtheria, gonorrhoea and mumps with their principal affected sites?

[SSC CGL Tier-I, 20 July 2023]

• (A) Brain, salivary glands, reproductive tract, throat
• (B) Throat, brain, reproductive tract, salivary glands
• (C) Brain, throat, salivary glands, reproductive tract
• (D) Brain, throat, reproductive tract, salivary glands

Answer: (D) Brain, throat, reproductive tract, salivary glands

Explanation: Alzheimer’s primarily affects the brain; diphtheria often affects the throat and nose; gonorrhoea commonly involves the reproductive tract; and mumps frequently affects salivary glands. Diphtheria and gonorrhoea are bacterial, whereas mumps is viral and Alzheimer’s is non-infectious.

Q58. Which among rabies, leprosy, malaria and Ebola is bacterial?

[SSC CHSL Tier-I (2022 cycle), 10 March 2023]

• (A) Rabies
• (B) Leprosy
• (C) Malaria
• (D) Ebola

Answer: (B) Leprosy

Explanation: Leprosy is a chronic infection mainly caused by Mycobacterium leprae; it can damage skin and peripheral nerves. Rabies and Ebola are viral infections, while malaria is protozoan. Early leprosy detection and multidrug therapy prevent many disabilities.

Q57. Which disease is viral rather than bacterial or protozoan?

[SSC CHSL Tier-I (2022 cycle), 21 March 2023]

• (A) Chickenpox
• (B) Tuberculosis
• (C) Whooping cough
• (D) Malaria

Answer: (A) Chickenpox

Explanation: Chickenpox results from the varicella-zoster virus. Tuberculosis is caused by Mycobacterium tuberculosis, whooping cough by Bordetella pertussis, and malaria by Plasmodium parasites. The infectious agent determines whether antibiotics, antivirals or antiparasitic treatment may be appropriate.

Q56. Which is NOT a bacterial disease?

[SSC MTS (2022 cycle), 12 May 2023]

• (A) Cholera
• (B) Typhoid
• (C) Rabies
• (D) Plague

Answer: (C) Rabies

Explanation: Rabies is caused by a lyssavirus and is usually transmitted through the saliva of an infected mammal. Cholera, typhoid and plague are bacterial diseases. Appropriate rabies post-exposure prophylaxis must be initiated promptly after a potentially infectious exposure.

Q55. Which is a plausible length for many typical bacterial cells?

[SSC CPO, 5 October 2023]

• (A) 3–5 micrometres
• (B) 1–40 millimetres
• (C) 30–50 millimetres
• (D) 0–3 nanometres

Answer: (A) 3–5 micrometres

Explanation: Many rod-shaped bacteria are only a few micrometres long, making 3–5 µm a realistic general value. Bacterial sizes vary widely among species. Micrometres, rather than millimetres, are the relevant unit for most ordinary bacterial cells.

Q54. Which traditional serological test is linked to suspected typhoid fever?

[SSC Stenographer, 13 October 2023]

• (A) Peripheral smear for malaria
• (B) C-reactive protein alone
• (C) Widal test
• (D) Vivax test

Answer: (C) Widal test

Explanation: The Widal assay tests for agglutinating antibodies against Salmonella enterica serovars Typhi and Paratyphi. Because false positives and negatives occur, it should not be treated as definitive confirmation; blood cultures are generally more useful in early enteric fever.

Q53. Which disease is bacterial: AIDS, COVID-19, polio or typhoid?

[MP Forest Guard/Jail Prahari, 7 June 2023]

• (A) AIDS
• (B) COVID-19
• (C) Polio
• (D) Typhoid

Answer: (D) Typhoid

Explanation: Salmonella Typhi is responsible for typhoid fever, which can cause sustained fever and systemic illness. AIDS, COVID-19 and polio are viral diseases. Clean food, safe water and typhoid vaccination help reduce infections in at-risk settings.

Q52. Identify the pair of waterborne diseases: typhoid, cholera, chickenpox and conjunctivitis.

[TSPSC Assistant Engineer, 5 March 2023]

• (A) Chickenpox and conjunctivitis
• (B) Typhoid and cholera
• (C) Typhoid and chickenpox
• (D) Cholera and conjunctivitis

Answer: (B) Typhoid and cholera

Explanation: Typhoid and cholera are classic bacterial infections acquired through contaminated food or water. Chickenpox is transmitted chiefly through respiratory exposure and lesion contact. Conjunctivitis has several possible causes and is not generally classified with classic waterborne enteric diseases.

Q51. Typhoid fever is caused by which broad type of organism?

[Delhi Police Constable, 23 November 2023]

• (A) Protozoan
• (B) Bacterium
• (C) Fungus
• (D) Virus

Answer: (B) Bacterium

Explanation: Typhoid fever is a systemic bacterial infection caused by Salmonella Typhi. Its bacteria enter through contaminated food or drinking water and can spread through the bloodstream. Prompt diagnosis and susceptibility-guided antibiotics help prevent potentially severe complications.

Q50. Which condition is not a viral illness?

[MP Patwari (2022 cycle), 20 April 2023]

• (A) Measles
• (B) Chikungunya
• (C) Diphtheria
• (D) Polio

Answer: (C) Diphtheria

Explanation: Diphtheria is caused by toxigenic strains of Corynebacterium diphtheriae and may form a dangerous throat pseudomembrane. Measles, chikungunya and polio are viral. Routine diphtheria-containing vaccines protect against severe illness and toxin-mediated complications.

Q49. Which one is non-communicable: chickenpox, common cold, diabetes or tuberculosis?

[SSC MTS (2022 cycle), 15 May 2023]

• (A) Chickenpox
• (B) Common cold
• (C) Diabetes
• (D) Tuberculosis

Answer: (C) Diabetes

Explanation: Diabetes is a metabolic disorder that does not spread between individuals. Chickenpox and the common cold are infectious viral diseases, while tuberculosis is a bacterial infection. Non-communicable and infectious categories describe how diseases arise and spread.

Q48. Microorganisms that cause disease are known collectively as what?

[SSC MTS (2022 cycle), 16 June 2023]

• (A) Toxins
• (B) Pathogens
• (C) Decomposers
• (D) Antibodies

Answer: (B) Pathogens

Explanation: Pathogens are biological agents that cause disease, including selected bacteria, viruses, fungi, protozoa and worms. A toxin is a harmful substance; an antibody is produced by the immune system. Most microorganisms are not human pathogens.

Q47. Which one of the following diseases is NOT classified as bacterial?

[RPSC RAS Prelims 2023, 1 October 2023]

• (A) Diphtheria
• (B) Plague
• (C) Pneumonia
• (D) Dengue

Answer: (D) Dengue

Explanation: Dengue is caused by a virus transmitted chiefly by Aedes mosquitoes. Diphtheria and plague are bacterial infections. Pneumonia has several possible causes, including bacteria such as Streptococcus pneumoniae, making dengue the unambiguously non-bacterial answer in this examination.

Q46. Tetanus is a nervous-system disorder caused by a toxin-producing what?

[RRB NTPC CBT-II, 17 June 2022]

• (A) Protist
• (B) Fungus
• (C) Parasitic worm
• (D) Bacterium

Answer: (D) Bacterium

Explanation: Clostridium tetani produces tetanospasmin, a potent neurotoxin that disrupts inhibitory nerve signalling and produces painful muscle spasms. Spores may enter through contaminated wounds. Vaccination, wound care and appropriate treatment prevent this serious bacterial disease.

Q45. Which listed condition is not caused by a bacterium?

[RRB Group D, 11 October 2022]

• (A) Tuberculosis
• (B) Syphilis
• (C) AIDS
• (D) Gonorrhoea

Answer: (C) AIDS

Explanation: AIDS is the advanced clinical syndrome of HIV infection and therefore has a viral cause. Tuberculosis, syphilis and gonorrhoea are bacterial. Syphilis is caused by Treponema pallidum, while Neisseria gonorrhoeae causes gonorrhoea.

Q44. Which disease is not ordinarily classified as sexually transmitted?

[RRB Group D, 26 August 2022]

• (A) Syphilis
• (B) Hepatitis B
• (C) HIV infection
• (D) Tuberculosis

Answer: (D) Tuberculosis

Explanation: Tuberculosis usually spreads through infectious airborne particles, especially from pulmonary disease. Syphilis and HIV can be sexually transmitted; hepatitis B may also spread by sexual contact. TB transmission depends primarily on respiratory exposure rather than sexual activity.

Q43. The Department of Biotechnology announced data-driven research in March 2022 to tackle which disease?

[RRB Group D, 12 September 2022]

• (A) HIV/AIDS
• (B) Tuberculosis
• (C) COVID-19
• (D) Cancer

Answer: (B) Tuberculosis

Explanation: The programme was announced on 24 March, World Tuberculosis Day, to strengthen research relating to TB elimination. Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. Surveillance, diagnostics, drug-resistance monitoring and effective treatment are important control tools.

Q42. Bharat Biotech partnered with Biofabri, a firm from which country, for TB vaccine development?

[RRB Group D, 1 September 2022]

• (A) Australia
• (B) United States
• (C) Canada
• (D) Spain

Answer: (D) Spain

Explanation: Biofabri is a Spanish biopharmaceutical company associated with tuberculosis vaccine development. New TB vaccine research seeks better protection against pulmonary disease. Existing BCG vaccination is particularly helpful against some severe forms of childhood tuberculosis, but protection is not complete.

Q41. Evaluate:
I. Tuberculosis is viral and airborne.
II. Chickenpox is viral and chiefly food/water-borne.

[SSC CPO Tier-I, 11 November 2022]

• (A) Only I is true
• (B) Only II is true
• (C) Both are false
• (D) Both are true

Answer: (C) Both are false

Explanation: Tuberculosis is bacterial, although pulmonary TB does spread through air; therefore statement I is false. Chickenpox is viral but is spread mainly by respiratory exposure and direct contact with lesions, not routinely through contaminated drinking water.

Q40. Which trio correctly names the structural regions of a bacterial flagellum?

[SSC CGL Tier-I, 1 December 2022]

• (A) Head, tail, lower body
• (B) Filament, tail, hook
• (C) Basal body, tail, filament
• (D) Filament, hook, basal body

Answer: (D) Filament, hook, basal body

Explanation: The bacterial flagellum has a basal body that anchors its motor, a curved hook that couples the motor to the filament, and a long external filament. In motile bacteria this rotating apparatus helps movement through liquid environments.

Q39. Sulpha medicines are primarily grouped under which type of drugs?

[UPPSC PCS Prelims 2022]

• (A) Analgesics
• (B) Antibacterials
• (C) Antacids
• (D) Antipyretics

Answer: (B) Antibacterials

Explanation: Sulphonamides, often called sulpha drugs, are synthetic antibacterial agents that interfere with bacterial folate metabolism. They do not treat viruses. Antibiotic selection must take resistance patterns, bacterial susceptibility and patient factors into account.

Q38. Haemophilus influenzae type b is an important cause of which childhood illness?

[UPPSC PCS Prelims 2022]

• (A) Bacterial meningitis
• (B) Influenza caused by influenza virus
• (C) Whooping cough
• (D) Malaria

Answer: (A) Bacterial meningitis

Explanation: Despite its name, Haemophilus influenzae is a bacterium, not the influenza virus. Encapsulated type b strains historically caused invasive disease, including meningitis in young children. Hib conjugate vaccination has greatly reduced severe infection in vaccinated populations.

Q37. Which disease is caused by a bacterial pathogen?

[UPSC NDA-I 2022, General Ability Test, 10 April 2022]

• (A) AIDS
• (B) Dengue fever
• (C) COVID-19
• (D) Typhoid fever

Answer: (D) Typhoid fever

Explanation: Typhoid fever is caused by Salmonella Typhi and commonly spreads through contaminated food or drinking water. AIDS, dengue and COVID-19 are viral illnesses. Distinguishing bacteria from viruses is essential because antibacterial drugs cannot directly treat viral infections.

Q36. Which condition is NOT usually considered a zoonotic infection?

[RPSC RAS Prelims, 27 October 2021]

• (A) Mucormycosis
• (B) Rabies
• (C) Plague
• (D) SARS

Answer: (A) Mucormycosis

Explanation: Mucormycosis is an opportunistic fungal infection acquired mainly from environmental spores, not usually an animal-to-human infection. Rabies and plague are classic zoonoses. SARS also originated from zoonotic transmission before sustained human spread.

Q35. “The Clock is Ticking” was the theme for which awareness day in 2021?

[UPPSC PCS Prelims, 24 October 2021]

• (A) International Yoga Day
• (B) International Women’s Day
• (C) World Tuberculosis Day
• (D) World Malaria Day

Answer: (C) World Tuberculosis Day

Explanation: World Tuberculosis Day 2021 used the slogan “The Clock is Ticking” to highlight the urgency of ending TB. The annual event occurs on 24 March, marking Robert Koch’s 1882 discovery announcement concerning Mycobacterium tuberculosis.

Q34. Which species primarily causes Hansen’s disease?

[SSC CHSL (2020 cycle), 12 April 2021]

• (A) Mycobacterium tuberculosis
• (B) Mycobacterium leprae
• (C) Bordetella pertussis
• (D) Neisseria gonorrhoeae

Answer: (B) Mycobacterium leprae

Explanation: Mycobacterium leprae primarily causes Hansen’s disease, or leprosy. Its slowly progressive infection can affect skin and peripheral nerves, producing areas of altered sensation. Timely multidrug therapy cures the infection and helps prevent disability.

Q33. Which disease is not caused by a virus?

[SSC CHSL (2020 cycle), 11 August 2021]

• (A) Leprosy
• (B) Measles
• (C) Smallpox
• (D) Rabies

Answer: (A) Leprosy

Explanation: Leprosy is bacterial, usually caused by Mycobacterium leprae. Measles, smallpox and rabies are viral diseases. The confusion often arises because all four can be infectious, but different microbial groups and preventive strategies apply.

Q32. The agent responsible for cholera belongs to which microbial group?

[SSC MTS (2020 cycle), 7 October 2021]

• (A) Protozoa
• (B) Bacteria
• (C) Viruses
• (D) Fungi

Answer: (B) Bacteria

Explanation: Cholera is caused by the bacterium Vibrio cholerae. Toxigenic strains produce an enterotoxin that drives water and electrolyte loss into the intestine. Severe infection requires urgent rehydration, sometimes supplemented by clinician-selected antibiotics.

Q31. Who conducted pioneering human cholera vaccination in 1885?

[SSC MTS (2020 cycle), 6 October 2021]

• (A) Jaime Ferrán
• (B) Albert Calmette
• (C) Jonas Salk
• (D) Edward Jenner

Answer: (A) Jaime Ferrán

Explanation: Jaime Ferrán developed and used an early live bacterial cholera vaccine in Spain in 1885. Albert Calmette was associated with BCG vaccine development; Jonas Salk developed an inactivated polio vaccine, and Edward Jenner pioneered smallpox vaccination.

Q30. Which disease among these is bacterial, not viral?

[SSC GD Constable, 14 December 2021]

• (A) Roseola
• (B) Plague
• (C) Ebola
• (D) AIDS

Answer: (B) Plague

Explanation: Plague is caused by Yersinia pestis, a bacterium associated with rodent fleas and mammalian reservoirs. Roseola, Ebola disease and AIDS involve viruses. Plague may present as bubonic, septicaemic or pneumonic disease and requires urgent antibiotics.

Q29. In India, World Leprosy Day is observed on which date?

[SSC CGL (2020 cycle), 18 August 2021]

• (A) 31 January
• (B) 22 January
• (C) 30 January
• (D) 25 January

Answer: (C) 30 January

Explanation: India observes Anti-Leprosy Day on 30 January, the death anniversary of Mahatma Gandhi. International World Leprosy Day is commonly marked on the final Sunday in January. Both observances seek awareness, timely diagnosis, treatment and stigma reduction.

Q28. Which country first introduced a WHO-approved Indian-made typhoid conjugate vaccine in a nationwide campaign?

[WBCS Prelims 2020]

• (A) Nepal
• (B) Bangladesh
• (C) Myanmar
• (D) Pakistan

Answer: (D) Pakistan

Explanation: Pakistan introduced typhoid conjugate vaccination in a major public-health campaign in 2019 using a WHO-prequalified Indian-manufactured vaccine. Conjugate vaccines protect against Salmonella Typhi, a bacterium increasingly associated with antibiotic-resistant enteric fever.

Q27. Why do antibiotics generally fail to cure infections caused by viruses?

[UPSC NDA 2020, General Ability Test, 6 September 2020]

• (A) Viruses have thick peptidoglycan walls
• (B) Antibiotics target bacterial structures or metabolism absent in viruses
• (C) Viruses always contain antibiotic-destroying enzymes
• (D) Every virus is a species of bacterium

Answer: (B) Antibiotics target bacterial structures or metabolism absent in viruses

Explanation: Antibiotics typically target bacterial pathways or structures, including cell-wall production, protein synthesis or DNA-related processes. Viruses lack these bacterial targets and replicate within host cells. An antibiotic may be warranted for a secondary bacterial infection, not for the virus itself.

Q26. Why is commonly used toothpaste generally basic in nature?

[WBCS Prelims 2019]

• (A) To increase oral acidity
• (B) To dissolve enamel quickly
• (C) To neutralise acids produced in the mouth
• (D) To supply bacterial food

Answer: (C) To neutralise acids produced in the mouth

Explanation: Plaque bacteria metabolise dietary sugars and produce acids that can demineralise tooth enamel. Many toothpastes include ingredients that help manage the oral environment, and brushing removes plaque. Good oral hygiene limits bacteria-associated dental caries.

Q25. What did RNTCP stand for before the programme was renamed NTEP?

[MP National Health Mission CHO, 10 December 2019]

• (A) Review of National TB Control Programme
• (B) Renewed National TB Control Programme
• (C) Revised National Tuberculosis Control Programme
• (D) Regional National TB Control Programme

Answer: (C) Revised National Tuberculosis Control Programme

Explanation: RNTCP meant Revised National Tuberculosis Control Programme. It was later renamed the National Tuberculosis Elimination Programme, reflecting a broader goal beyond control alone. The programme uses diagnosis, effective drug treatment and public-health follow-up to combat TB.

Q24. The historical Black Death pandemic was mainly associated with which disease?

[RRB Junior Engineer CBT-II, 1 September 2019]

• (A) Diphtheria
• (B) Plague
• (C) Meningitis
• (D) Cholera

Answer: (B) Plague

Explanation: The fourteenth-century Black Death was associated with plague, caused by Yersinia pestis. Rodent fleas played an important part in historical transmission, although pneumonic plague can spread through close respiratory exposure. The disease remains treatable with timely antibiotics.

Q23. Which statement about cholera is correct?

[UPSC NDA-I 2019, General Ability Test, 21 April 2019]

• (A) It is a disorder causing memory loss
• (B) It develops from drinking alcohol
• (C) It may follow ingestion of contaminated food or water
• (D) It is inherited as a genetic condition

Answer: (C) It may follow ingestion of contaminated food or water

Explanation: Cholera is an acute intestinal infection caused by toxigenic Vibrio cholerae. Contaminated food or water is the main transmission route. Severe watery diarrhoea may cause dangerous dehydration, making prompt oral or intravenous rehydration the central treatment.

Q22. How can some bacteria resist the antibiotic penicillin?

[UPSC NDA-I 2019, General Ability Test, 21 April 2019]

• (A) By storing penicillin in vacuoles
• (B) By producing the enzyme beta-lactamase
• (C) By converting penicillin into glucose
• (D) By becoming viruses

Answer: (B) By producing the enzyme beta-lactamase

Explanation: Certain resistant bacteria produce beta-lactamase enzymes that break down penicillins and related beta-lactam antibiotics. Resistance may also develop through altered drug targets or reduced entry. Rational prescription and completing appropriate treatment help limit selection of resistant strains.

Q21. BCG vaccination is mainly intended to protect against which disease?

[UPPSC LT Grade Assistant Teacher, 29 July 2018]

• (A) Cholera
• (B) Gout
• (C) Measles
• (D) Tuberculosis

Answer: (D) Tuberculosis

Explanation: BCG stands for Bacille Calmette–Guérin. This live attenuated vaccine is derived from Mycobacterium bovis and protects particularly against severe childhood forms of tuberculosis, including TB meningitis. Its protection against adult pulmonary TB varies.

Q20. What is a bacteriophage?

[WBCS Prelims 2017]

• (A) A virus that infects bacteria
• (B) A bacterium grown on agar
• (C) A fungus that causes illness
• (D) A protozoan that engulfs bacteria

Answer: (A) A virus that infects bacteria

Explanation: A bacteriophage is a virus that infects bacterial cells, sometimes destroying them through a lytic cycle. Because phages can target bacteria, researchers investigate their possible roles in treating certain antibiotic-resistant infections, although clinical applications require careful evaluation.

Q19. Which of the following diseases is caused by a protozoan rather than a bacterium?

[MPPSC State Service Prelims 2017, General Science]

• (A) Cholera
• (B) Diphtheria
• (C) Pneumonia
• (D) Malaria

Answer: (D) Malaria

Explanation: Malaria is caused by protozoan parasites belonging to Plasmodium. Cholera is caused by Vibrio cholerae, diphtheria by Corynebacterium diphtheriae, and bacterial pneumonia may be caused by Streptococcus pneumoniae. The question tests recognition of distinct infectious agents.

Q18. Which pairing is incorrect?

[UP Review Officer/Assistant Review Officer Prelims 2016]

• (A) Autoimmune disorder — rheumatoid arthritis
• (B) Genetic disorder — tuberculosis
• (C) Scabies — mite
• (D) Mental disorder — schizophrenia

Answer: (B) Genetic disorder — tuberculosis

Explanation: Tuberculosis is an acquired infectious disease caused by Mycobacterium tuberculosis, not a genetic disorder. Rheumatoid arthritis is autoimmune; scabies results from a parasitic mite infestation; and schizophrenia is a psychiatric illness. The question contrasts distinct categories of disease.

Q17. Which illness is commonly transmitted by contaminated water?

[UPPSC PCS Prelims, 10 May 2015]

• (A) Smallpox
• (B) Malaria
• (C) Cholera
• (D) Pulmonary tuberculosis

Answer: (C) Cholera

Explanation: Cholera spreads mainly through food or water contaminated with Vibrio cholerae. Smallpox was a viral infection spread principally through close contact; malaria is mosquito-borne; and pulmonary tuberculosis is airborne. Water safety and sanitation are essential for cholera prevention.

Q16. Which classical skin test is associated with detecting immune sensitisation to tuberculosis?

[UP Lower Subordinate Mains 2015]

• (A) Robert’s test
• (B) Widal test
• (C) Kahn test
• (D) Mantoux test

Answer: (D) Mantoux test

Explanation: The Mantoux tuberculin skin test checks delayed-type immune reactivity to tuberculosis antigens. It indicates TB infection or sensitisation, not necessarily active disease. Further clinical assessment and microbiological testing are needed before diagnosing active tuberculosis.

Q15. Of diphtheria, chickenpox and smallpox, which had been eradicated in India by 2014?

[UPSC Civil Services Prelims 2014]

• (A) Diphtheria and chickenpox only
• (B) Smallpox only
• (C) All three
• (D) None

Answer: (B) Smallpox only

Explanation: Smallpox, caused by variola virus, was eradicated globally in 1980 after intensive vaccination and surveillance. Diphtheria is bacterial and remains vaccine-preventable but not eradicated. Chickenpox is a viral infection and has not been globally eradicated.

Q14. Botulism is linked to which bacterial genus?

[UP Lower Subordinate Prelims 2013]

• (A) Azotobacter
• (B) Lactobacillus
• (C) Clostridium
• (D) Rhizobium

Answer: (C) Clostridium

Explanation: Botulism is caused by botulinum neurotoxin, produced mainly by Clostridium botulinum and certain related clostridia. This potent toxin blocks acetylcholine release, causing descending flaccid paralysis. Safe food handling and correct preservation reduce foodborne botulism risk.

Q13. The letters DPT refer to vaccines against which group?

[UPPSC PCS Mains 2013]

• (A) Tetanus, polio, plague
• (B) TB, polio, diphtheria
• (C) Diphtheria, pertussis, tetanus
• (D) Diphtheria, polio, leprosy

Answer: (C) Diphtheria, pertussis, tetanus

Explanation: DPT vaccination protects against three bacterial diseases: diphtheria, pertussis and tetanus. Protection against diphtheria and tetanus principally targets bacterial toxins, while pertussis components protect against Bordetella pertussis infection and its serious consequences.

Q12. The disease tuberculosis is caused by which kind of pathogen?

[CGPSC State Service Prelims 2012 cycle (held 9 July 2013), Q26]

• (A) Virus
• (B) Bacterium
• (C) Fungus
• (D) Protozoan

Answer: (B) Bacterium

Explanation: Tuberculosis is caused principally by Mycobacterium tuberculosis, a slow-growing bacterial pathogen. Pulmonary disease spreads through infectious airborne particles. Common features include prolonged cough, fever, night sweats and weight loss; diagnosis and complete multidrug treatment are important.

Q11. Match the organisms causing plague, AIDS, fungal scalp disease and malaria to their categories.

[UPPSC PCS Prelims 2012]

• (A) Bacterium, virus, fungus, protozoan
• (B) Virus, bacterium, protozoan, fungus
• (C) Protozoan, fungus, virus, bacterium
• (D) Fungus, protozoan, bacterium, virus

Answer: (A) Bacterium, virus, fungus, protozoan

Explanation: Plague is bacterial, AIDS is caused by HIV, many scalp fungal infections arise from dermatophytes, and malaria is protozoan. This comparison is important because treatment and transmission patterns differ sharply among bacteria, viruses, fungi and protozoa.

Q10. Which is a bacterial disease among these options?

[UPPSC PCS Mains 2010]

• (A) Tuberculosis
• (B) Influenza
• (C) Polio
• (D) Malaria

Answer: (A) Tuberculosis

Explanation: Tuberculosis is caused by Mycobacterium tuberculosis, an acid-fast bacterium that commonly affects the lungs. Influenza and polio are viral, while malaria results from Plasmodium parasites. TB requires properly selected combination antimicrobial treatment.

Q9. Which vaccine is routinely administered to newborns to protect against a severe bacterial disease?

[UP Government Teacher (Home Science) 2010]

• (A) Measles vaccine
• (B) BCG vaccine
• (C) MMR vaccine
• (D) None of these

Answer: (B) BCG vaccine

Explanation: BCG is used in many countries, including India, soon after birth to protect against severe tuberculosis in children. Measles and MMR vaccines target viral diseases and are administered according to different schedules. BCG does not guarantee complete protection against all TB.

Q8. What is the familiar alternative name of tetanus?

[UPPSC Special Mains 2008]

• (A) Gas gangrene
• (B) Shingles
• (C) Lockjaw
• (D) Whooping cough

Answer: (C) Lockjaw

Explanation: Tetanus is often called lockjaw because tetanospasmin can cause jaw muscle spasms and rigidity. The toxin comes from Clostridium tetani, whose spores may enter contaminated wounds. Tetanus cannot be prevented by antibiotics alone; vaccination is essential.

Q7. Which listed condition is not caused by a virus?

[UP Lower Subordinate Prelims 2008]

• (A) Viral hepatitis A
• (B) Influenza
• (C) Mumps
• (D) Typhoid

Answer: (D) Typhoid

Explanation: Typhoid is bacterial, caused by Salmonella Typhi. Influenza, mumps and hepatitis A are viral. The word jaundice describes a symptom with different causes, so specifying a viral hepatitis type avoids incorrectly categorising every jaundice case as viral.

Q6. Which of these diseases is viral rather than bacterial?

[WBCS Prelims 2006]

• (A) Cancer as a single disease category
• (B) Leukaemia as a single disease category
• (C) Typhoid
• (D) Yellow fever

Answer: (D) Yellow fever

Explanation: Yellow fever is caused by a flavivirus transmitted by infected mosquitoes. Typhoid is caused by Salmonella Typhi, a bacterium. Cancer and leukaemia are broad neoplastic conditions, not single communicable pathogen-defined diseases, so yellow fever is the clear viral choice.

Q5. DPT immunisation offers protection against which three diseases?

[UP Lower Subordinate Prelims 2004]

• (A) Tetanus, polio and plague
• (B) Tuberculosis, polio and diphtheria
• (C) Diphtheria, pertussis and tetanus
• (D) Diphtheria, polio and leprosy

Answer: (C) Diphtheria, pertussis and tetanus

Explanation: DPT is a combination vaccine for diphtheria, pertussis and tetanus. These are distinct bacterial conditions: diphtheria and tetanus can cause toxin-mediated illness, and whooping cough is a respiratory disease due to Bordetella pertussis.

Q4. Consider:
(1) the femur is the longest human bone;
(2) cholera is bacterial;
(3) athlete’s foot is viral.

Which are correct?

[UPSC Civil Services Prelims 2004]

• (A) 1 and 2 only
• (B) 2 and 3 only
• (C) 1 and 3 only
• (D) All three

Answer: (A) 1 and 2 only

Explanation: The femur is generally the longest bone of the human body, and cholera is caused by Vibrio cholerae, a bacterium. Athlete’s foot is instead a fungal infection, so the third statement is incorrect.

Q3. AIDS belongs to which category of disease?

[WBCS Prelims 2003]

• (A) Viral disease
• (B) Fungal disease
• (C) Bacterial disease
• (D) Inherited genetic disease

Answer: (A) Viral disease

Explanation: AIDS is the advanced stage of infection with human immunodeficiency virus. HIV progressively damages immune function. It is not caused by bacteria, fungi or direct Mendelian inheritance. Antiretroviral therapy can suppress HIV replication and reduce disease progression.

Q2. Which option is a classically recognised infectious bacterial disease?

[WBCS Prelims 2002]

• (A) All forms of conjunctivitis
• (B) Diphtheria
• (C) Influenza
• (D) Measles

Answer: (B) Diphtheria

Explanation: Diphtheria is caused by toxigenic Corynebacterium diphtheriae. Influenza and measles are viral. Conjunctivitis is a clinical inflammation with infectious and noninfectious causes, so it is not unambiguously bacterial. Diphtheria vaccination and timely treatment are important safeguards.

Q1. Which statement about viroids, prions, mycoplasmas and rickettsiae is correct?

[UPSC Civil Services Prelims 2002]

• (A) Prions are free-living cells
• (B) Mycoplasmas have a conventional peptidoglycan wall
• (C) Viroids contain single-stranded RNA
• (D) All rickettsiae lack any cellular wall

Answer: (C) Viroids contain single-stranded RNA

Explanation: Viroids are small infectious single-stranded RNA molecules mainly associated with plant diseases. Prions are infectious proteins, not cells; mycoplasmas lack a conventional bacterial cell wall; and rickettsiae are bacteria with cell-envelope structures.