Biology · Science General

Disease Causative Agents

2,258 Questions

Disease causative agents questions test your understanding of viral, bacterial, and fungal infections, along with their transmission methods. These are common topics in general science sections of SSC and railways exams. Practice these questions to accurately identify disease pathogens and symptoms.

Viral diseasesFoodborne illnessesDisease transmission methodsExtrinsic disease factorsCommon pathogens

Disease Causative Agents Questions

Multiple choice

Which of the following statements about rheumatic fever is false?

  1.  It only affects the elderly.

  2. It affects the peri-arteriolar connective tissues of the body.

  3. It is believed to be caused by antibody cross-reactivity.

  4. It shows no evidence of genetic susceptibility.

  5. The recurrence of rheumatic fever is relatively common in the absence of maintenance of low dose antibiotics.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rheumatic fever usually affects young children and adolescents.

Multiple choice

Bacillus anthracis and Escherichia coli are the two most prominent extracellular bacterial pathogens. Extracellular bacteria try to avoid killing by

  1. activating neutrophils

  2. accelerating complement activation

  3. synthesising capsules

  4. deviating complement deposition to the cell membrane

  5. limiting variation in their antigens
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Capsules do not adhere readily to phagocytic cells and may cover carbohydrate molecules which could be recognised by phagocyte receptors.

Multiple choice

Which among the following is a bacterial inflammation of breast tissue in human beings?

  1. Gastroenteritis

  2. Mastitis

  3. Sepsis

  4. Meningitis

  5. Spontaneous bacterial peritonitis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mastitis is the inflammation of breast tissue. S. aureus is the most common etiological organism responsible, but S. epidermidis and streptococci are occasionally isolated as well. Mastitis can be classified as milk stasis, non-infectious or infectious inflammation and abscess.

Multiple choice

Streptococcus pyogenes owes its major success as a pathogen to its ability to colonise and rapidly multiply and spread in its host while evading phagocytosis and confusing the immune system. Which among the following statements is correct regarding the pyrogenic streptococcal exotoxins SPE, A, B and C?

  1. They are M proteins.

  2. They cause post-streptococcal autoimmune disease.

  3. They produce high titers of anti-streptolysin O.

  4. They have hyaluronidase activity.

  5. They are superantigens.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The superantigens combine with the framework regions of certain TCR V beta families irrespective of their complementarity determining regions.

Multiple choice

Many years ago, leprosy was considered a mysterious disease associated with some type of curse, and people suffering from leprosy were isolated and ostracised. Lepromatous leprosy is characterised by

  1. poor T-cell responses

  2. good cell-mediated immunity

  3. good lepromin dermal response

  4. poor B-cell responses

  5. poor phagocytic ability
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The poor T-cell responses specific for leprosy bacillus prevent the host from mounting a killing response and the bacilli grow profusely.

Multiple choice

Prions are highly infectious particles leading to various diseases in human beings. Prions are

  1. relatively sensitive to protease digestion

  2. associated with CGD

  3. present in follicular dendritic cells in individuals with transmissible spongiform encephalopathies

  4. normally eliminated by B-cells

  5. destroyed by macrophages
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

FDCs naturally express high levels of the normal prion protein which then becomes abnormal following exposure to the transmissible spongiform encephalopathy (TSE) agent.

Multiple choice

Which among the following statements regarding leprosy is false?

  1. Leprosy is an infectious skin and nerve disease.

  2. Children are more likely to get leprosy than adults.

  3. Tuberculoid leprosy is less contagious than other forms.

  4. Leprosy is caused by a fast-growing type of bacteria.

  5. Leprosy has a very long incubation period.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Leprosy is caused by a slow-growing type of bacteria called Mycobacterium leprae (M. leprae). Leprosy is also known as Hansen's disease, after the scientist who discovered M. leprae in 1873.

Multiple choice

Which among the following statements regarding baculoviruses is incorrect?

  1. Baculoviruses are lytic viruses, primarily pathogenic for insects.

  2. Non-genetically modified wild type baculoviruses are not capable of infecting vertebrate cells.

  3. Baculovirus is insensitive to human complement.

  4. The budded form of the virus routinely used in research is non-infectious for the insect host.

  5. Polyhedrin negative baculovirus expression system is susceptible to desiccation and UV light.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Transmission of baculovirus is through direct contact with the infective virus/vector. Baculovirus is highly sensitive to human complement and therefore, should an exposure occur, rapid inactivation of the virus is anticipated.

Multiple choice

Match the following:

 
Column - I (Infectious fever types) Column - II (Causative pathogens)
P. West Nile fever 1. Rickettsia rickettsii
Q. Rocky Mountain spotted fever 2. Flavi virus
R. Rat-bite fever 3. Giardia lamblia
S. Q fever 4. Coxiella burnetii
5. Streptobacillus moniliformis

  1. P - 2, Q - 1, R - 5, S - 4

  2. P - 5, Q - 1, R - 2, S - 3

  3. P - 2, Q - 4, R - 3, S - 1

  4. P - 5, Q - 3, R - 1, S - 4

  5. P - 2, Q - 4, R - 5, S - 1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct sequence is P - 2, Q - 1, R - 5, S - 4.

Multiple choice

Today most of the diseases are _____ in nature.

  1. airborne

  2. waterborne

  3. food borne

  4. animal borne
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Waterborne diseases are among the most common contemporary diseases globally. Diseases like cholera, typhoid, hepatitis A, and dysentery primarily spread through contaminated water sources. While airborne, foodborne, and animal-borne diseases exist, waterborne transmission remains the most widespread cause of infectious diseases.

Multiple choice

Which of the following is a communicable disease?

  1. Cancer

  2. Diabetes

  3. Diphtheria

  4. Rheumatism
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diphtheria is a communicable disease caused by the bacterium Corynebacterium diphtheriae, which spreads through respiratory droplets or direct contact. Cancer, Diabetes, and Rheumatism are non-communicable diseases - they cannot be transmitted from person to person.

Multiple choice

Inflammation of the membranes covering the brain and spinal cord is referred to as

  1. sinusitis

  2. meningitis

  3. hepatitis

  4. tonsillitis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Meningitis specifically refers to inflammation of the meninges, the protective membranes covering the brain and spinal cord. The prefix "mening-" relates to these membranes, while "-itis" indicates inflammation. Sinusitis affects sinuses, Hepatitis affects the liver, and Tonsillitis affects tonsils.