MCQs on Rickettsiae and bacterial zoonotic diseases- obligate intracellular pathogens

              MCQ on Rickettsiae and zoonotic diseases- obligate intracellular pathogens
1) What are the different types of medically important Rickettsial infections?
Select all the correct answers:
a) Epidemic and endemic typhus
b) Scrub typhus
c) Yellow fever
d) Rocky Mountain spotted fever

2) All the statements given below are correct about 'epidemic typhus', Except?
a) Transmitted to humans lice (vector)
b) Doxycycline is the drug of choice
c) Fever lasts for about two weeks
d) The causative pathogen is Rickettsia typhi

3) Among the Rickettsia spp listed, which one is responsible for rickettsial pox in humans, transmitted by vector mites, and exhibits early symptoms such as fever, rashes, and flu-like symptoms that closely resemble varicella infection?
a) Rickettsia rickettsi
b) Rickettsia akari
c) Rickettsia prowazekii
d) Rickettsia australis

4) Which of the following statements is incorrect about the characteristics of  Rocky Mountain spotted fever?
a) It is caused by Rickettsia rickettsii
b) Predominant in the eastern and southeastern regions of the United States
c) Fever and Skin rashes develop within 6 hours after a tick bite
d) Ticks are the primary vectors

5) All of the statements given below are correct about the Ehrlichiosis infection in humans, EXCEPT?
a) Ehrlichia chaffeensis is the causative organism
b) Fleas are the vectors that transmit Ehrlichiosis infection in humans
c) The infection represents an Intracellular inclusion called morulae
d) Blood tests can detect antibodies against Ehrlichia chaffeensis or the genetic material of the bacteria.

6) The following bacterial zoonotic diseases 
  • resembles the symptoms of influenza and pneumonia
  • can be spread to humans most commonly by inhalation of infected aerosols and dust
  • primary reservoirs are sheep, and goats

Name the disease 

a) Rocky mountain fever
b) Q fever
c) Dengue fever
d) Yellow fever

7) ….................................. causes endemic typhus or murine typhus which is transmitted to humans primarily through rats and cats fleas.
a) Ehrlichia chaffeensis
b) Rickettsia rickettsii
c) Coxiella burnetii
d) Rickettsia typhi

8) Which of the following serological test should be performed for the positive diagnosis of the Rickettsia rickettsii from skin biopsy specimens of a rash?
a) Complement fixation test
b) Indirect Immunofluorescence technique
c) Schick skin test
d) Agglutination test

9) What is the effective drug regimen used in the treatment of chronic Q fever?
a) Combination therapy with doxycycline and hydroxychloroquine for up to 18 months
b) Doxycycline for 18 months
c) Combination therapy with penicillin and fluoroquinolones for 12 months
d) Antibiotics do not work in this phase of illness

10) Which of the following statements is most correct regarding Coxiella burnetii infections?
a) Transmitted to humans by the bite of vector ticks
b) Can cause atypical pneumonia
c) Fever, chills and headache are the common symptoms
d) Resistant to various chemical and physical agents

11) Which of the following disease is NOT a tick-borne rickettsial disease?
a) Epidemic typhus
b) Ehrlichiosis
d) Scrub typhus
e) Tularemia

12) All of the following statements are true about the 'Scrub typhus' disease caused by Rickettsia spp, EXCEPT?
a) The common symptoms are fever and body aches
b) Ulcer known as eschar ulcer appears at the site of the bite
c) Cases usually occur in people who work on farms
d) The causative agent is Rickettsia australis

13) ......................................also known as 'recrudescent typhus', is a late relapse of epidemic typhus that is caused by R. prowazekii
a) Rickettsialpox
b) Scrub typhus
c) Brill-Zinsser disease
d) Murine typhus

14) What are the primary hosts or sources of flea-borne typhus, also known as murine typhus, among the following options?
a) Rats
b) Dogs
c) Ticks
d) Mites

15) Which of the following is NOT the proper preventive method to control Rickettsial diseases?
a) Use of insecticides to control possible vectors and reservoirs of the pathogen
b) Use of tick and insect repellent while traveling to endemic areas
c) Proper hygiene and cleanliness to eliminate lice and fleas
d) Use of sulfonamides for the treatment of typhus fever
16) A PCR test is a commonly used molecular diagnostic method for the detection of all medically important Rickettsial diseases, the test is less sensitive during which stage of this disease? 
Select all the correct answers
a) Late stage of the infection
b) Within 2-3 days of the infection
c) Between 1-2 weeks of the infection
d) 1 week after the antibiotic therapy

17) Serological testing is essential for accurately diagnosing rickettsial infections, as it can produce positive result when conducted during both the acute and convalescent phases of the infection.
Select all the statements that are true about the diagnosis procedure done during these phases
a) Sample is collected within initial 14 days in the acute phase
b) Decrease in IgG antibody titer is a confirmatory result of the infection
c) Convalescent samples are collected after the 2-3 weeks of the acute phase
d) Collection of samples for antibody titer is done in the acute phase

18) 'Anaplasmosis' in humans mostly occurrs in which of the following regions of the world?
a) Australia
b) Japan
c) United kingdoms
d) United States

19) Name the most frequently used specimen for the microscopic diagnosis of the rickettsial diseases
a) Blood
b) Nose swab
c) Throat secretions
d) Urine

20) Which of the following best describes the primary general characteristic of the pathogen Coxiella burnetii?
a) A gram-negative rod
b) Causes Lyme disease
c) Transmitted to humans via tick bites
d) Usually resistant to high temperatures and chemical disinfectants

Multiple Choice Answers Review:
1-a) Epidemic and endemic typhus & (b) Scrub typhus group, and (d) Rocky Mountain spotted fever.
Yellow fever is caused by the virus Yellow fever virus (YFV), an enveloped RNA virus belong to Flaviviridae family.

2-d) The causative pathogen is Rickettsia typhi. Rickettsia prowazekii is the causative agent of epidemic typhus, transmitted to humans through vector 'lice'. Rickettsia typhi causes murine typhus that is transmitted to humans through vector 'fleas'.

3- b) Rickettsia akari, rickettsialpox is characterized by fever, rash, and other flu-like symptoms.

4-c) Fever and Skin rashes develop within 6 hours after the tick bite. 
Symptoms of Rocky Mountain spotted fever typically appear within 2 to 14 days after a tick bite

5-b) Fleas are the vectors that transmit Ehrlichiosis infection in humans. Ticks are vectors of Human monocytic ehrlichiosis.    

6-b) Q fever, it is transmitted to humans through air and dust that contain animal body fluids.           
Dengue fever and yellow fever are 'viral diseases', and Rocky mountain is a 'bacterial infection' caused by a tick bite. 

7-d) Rickettsia typhi, it is a causative agent of flea borne murine typhus. People can also breathe in infected flea dirt or rub it into their eyes. Common symptoms are fever, chills, body aches, vomiting and skin rashes.
R. prowazekii causes epidemic typhus, R. rickettsii causes Rocky mountain fever. C. burnetii causes Q fever and pneumonia, Ehrlichia chaffeensis is spread to humans by the bite of ticks

8-b) Indirect Immunofluorescence technique
Antibody level measurement helps in the proper diagnosis of Rickettsial diseases   

9-a) Combination therapy with doxycycline and hydroxychloroquine for up to 18 months

10-a) Transmitted to humans by the bite of vector ticks. Humans are infected by the inhalation of contaminated aerosols.

11-b) Scrub typhus, the vector is chiggers (microscopic mites) for scrub typhus

12-d) The causative agent is Rickettsia australis 
The causative organism is Orientia tsutsugamushi

13-c) Brill-Zinsser disease, the disease occurs when a person who has previously recovered from epidemic typhus experiences a reactivation of the infection years or even decades later.

14-a) Rats
15-d) Use of sulfonamides for the treatment of epidemic and endemic typhus.
Doxycycline and other tetracyclines are the primary drugs of choice for treatment of most infections caused by Rickettsia.

16- a)Late stage of the infection, d)1 week after the antibiotic therapy
PCR results are positive mostly within 14 days of the infection

17- b)Decrease in IgG antibody titer is a confirmatory result of the infection
(Antibody level is measured to observe the increase in IgG that occurs during the infection)

18- d) the United States
19- a) Blood
20- d) Resistant to high temperatures and chemical disinfectants
 (C. burnetii is a gram-negative coccobacillus that causes Q fever, human transmission is via tick bites)
Lyme disease is caused by the bacteria Borrelia burgdorferi 


Post a Comment