MCQ on Rickettsiae and zoonotic diseases- gram negative bacteria



1) What are the different types of medically important Rickettsial infections?
Select all the correct answers:
a) Epidemic and endemic typhus
b) Scrub typhus group
c) Yellow fever
d) Rocky Mountain spotted fever

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

3) Which of the following Rickettsia spp causes rickettsialpox in humans transferred from vector called mites, mild fever and rashes are early symptoms that resemble the symptoms of 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 of the ticks' bite
d) Ticks are the primary vectors

5) All of the statements given below are correct about the Ehrlichiosis infections in humans, EXCEPT?
a) Ehrlichia chaffeensis is the causative organism
b) Ticks are the vectors that transmit Ehrlichiosis infection in humans
c) The infection represents an Intracellular inclusion called morulae
d) The infection case was first reported in China

6) The following bacterial zoonotic diseases 
  • resembles the symptoms of influenza and pneumonia
  • can be spread to humans most commonly by inhalation of air and dust
  • can cause infections in sheep, goats, and other cattle

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 serological test is mostly preferred 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 about the antigenic forms of Coxiella burnetii?
a) The antigens exist in two phases 1 and 2 and phase 1 is a virulent form
b) The antigens are less pathogenic when grown in laboratory animals
c) Both a and b
d) None of the above

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

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 called 'recrudescent typhus', it is a late relapse of epidemic typhus that is transmitted by vector human body louse and the causative organism is R. prowazekii
a) Rickettsialpox
b) Scrub typhus
c) Brill-Zinsser disease
d) Murine typhus

14) Which of the following are the reservoirs of the flea-borne typhus also called murine typhus?
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 the 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) A serological testing is a test done usually in two phases of rickettsial infection, acute phase, and convalescent-phase. 
Select all the statements that are true about the diagnosis 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 has mostly occurred in which of the following parts of the world?
a) United States
b) United kingdoms
c) Australia
d) Japan

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

20) Which of the following is the most correct 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

2-d) The causative pathogen is Rickettsia typhi
3- b) Rickettsia akari
4-c) Fever and Skin rashes develop within 6 hours of the ticks' bite 
5-d) The infection case was first reported in China       
(it was first reported in the USA)
6-b) Q fever 
Dengue fever and yellow fever are 'viral diseases', and Rocky mountain is a 'bacterial infection' caused by a tick bite. Q fever is transmitted to humans through air and dust that contain animal body fluids           
7-d) Rickettsia typhi
R. typhi causes endemic typhus, 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-b) The antigens are less pathogenic when grown in laboratory animals

11-b) Scrub typhus

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

13-c) Brill-Zinsser disease
14-a) Rats
15-d) Use of sulfonamides for the treatment of epidemic and endemic typhus

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- a) the United States
19- c) 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 

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