Brucellosis

Brucellosis

Q. 1

All are about brucella except 

 A

B. abortus is capnophilic

 B

Transmission by aerosol can occur occasionally

 C

Paesturisation destroys it

 D

2ME is used to detect IgA

Q. 1

All are about brucella except 

 A

B. abortus is capnophilic

 B

Transmission by aerosol can occur occasionally

 C

Paesturisation destroys it

 D

2ME is used to detect IgA

Ans. D

Explanation:

2ME is used to detect IgA [Ref : Ananthanarayan 8/e p. 341-346]

  • Brucella is a wides pread zoonotic disease mainly seen in cattle sheep, goats, pigs and camels. – Brucella is strictly a parasite of animals.

-No human to human transmission has been identified and infection in human occurs only by contact with infected animals or animal products.

– The disease in the man is known as Malta fever, Mediterranean fever or undulant fever.


Q. 2

A farmer presenting with fever on and off for the past 4 years was diagnosed to be suffering from chronic brucellosis. All of the following serological tests are indicatedl in the diagnosis of chronic brucellosis except:

 A

Standard agglutination test

 B

Standard agglutination test

 C

Complement fixation test

 D

Coomb’s test

Q. 2

A farmer presenting with fever on and off for the past 4 years was diagnosed to be suffering from chronic brucellosis. All of the following serological tests are indicatedl in the diagnosis of chronic brucellosis except:

 A

Standard agglutination test

 B

Standard agglutination test

 C

Complement fixation test

 D

Coomb’s test

Ans. A

Explanation:

Patient is suffering from chronic brucellosis.

Standard agglutination test identifies mainly the IgM antibodies, which is usually positive in acute infection but may be only weakly positive or even negative in chronic cases.

Standard agglutination test is therefore useful in diagnosing acute brucellosis, not chronic brucellosis.

Brucellosis is a bacterial zoonosis transmitted directly or indirectly to humans from infected animals, predominantly domesticated ruminants and swine. The disease is known as undulant fever because of its remittent character.

Although brucellosis commonly presents as an acute febrile illness, its clinical manifestations vary widely, and definitive signs indicative of the disease is not present.

Clinical diagnosis must be supported by the results of bacteriologic and/or serologic tests.

Ref: Brucellosis in Humans and Animals By Michael J.Corbel, Page 79 ; Harrisosns Principles of Internal Medicine, Chapter 157 ; Brucellosis Research: An Evaluation – A Report By National Research Council (U.S.), Page 45


Q. 3

Brucella is transmitted by all of the following, EXCEPT:

 A

Through the placenta of animals

 B

Aerosol transmission

 C

Person to person

 D

Eating uncooked food

Q. 3

Brucella is transmitted by all of the following, EXCEPT:

 A

Through the placenta of animals

 B

Aerosol transmission

 C

Person to person

 D

Eating uncooked food

Ans. C

Explanation:

Usual transmission of brucella is from infected animals to man. Man to man transmission is not known.

Most commonly, infection occurs from direct contact with infected tissues especially placenta.

Ingesting infected food and inhaling aerosolised bacteria are established modes of transmission of brucella.

Ref: Textbook of Preventive and Social Medicine, Park, 20th Edition, Chapter 5, Page 253.


Q. 4

Which among the following causes Malta fever?

 A

Treponema pallidum

 B

Borrelia burgdorferi

 C

Brucella melitensis

 D

Pseudomonas aeruginosa

Q. 4

Which among the following causes Malta fever?

 A

Treponema pallidum

 B

Borrelia burgdorferi

 C

Brucella melitensis

 D

Pseudomonas aeruginosa

Ans. C

Explanation:

Brucellosis, also called Bang’s disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever.

The infection is transmitted from animals to humans.

Brucella abortus (cattle), B suis (hogs), and B melitensis (goats) are the main agents.

Transmission to humans occurs by contact with infected meat (slaughterhouse workers), placentae of infected animals (farmers, veterinarians), or ingestion of infected unpasteurized milk or cheese.

The incubation period varies from a few days to several weeks.

Brucellosis is a systemic infection that may become chronic.

B. melitensis infections tend to be more severe and prolonged, whereas those caused by B. abortus are more self-limited.
After an incubation period of 1 to 3 weeks, nonspecific symptoms such as fever, chills, fatigue, malaise, anorexia, and weight loss occur. The onset can be acute or gradual.
The undulating (rising-and-falling) fever pattern that gives the disease its name occurs in a minority of patients.
 
The treatment of choice is tetracycline plus rifampin.
Prevention of brucellosis involves pasteurization of milk, immunization of animals, and slaughtering of infected animals. There is no human vaccine. 
Ref: Levinson W. (2012). Chapter 20. Gram-Negative Rods Related to Animal Sources (Zoonotic Organisms). In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.

Q. 5

A farmer who is working in poultry developed acute onset of fever with chills. On physical examination, there is hepatosplenomegaly and lymphadenopathy. Blood culture shows Brucella abortus. He must have got the infection through all the following ways, EXCEPT:

 A

Infected meat

 B

Ingestion of raw milk

 C

Man to man

 D

Contact with aborted fetuses

Q. 5

A farmer who is working in poultry developed acute onset of fever with chills. On physical examination, there is hepatosplenomegaly and lymphadenopathy. Blood culture shows Brucella abortus. He must have got the infection through all the following ways, EXCEPT:

 A

Infected meat

 B

Ingestion of raw milk

 C

Man to man

 D

Contact with aborted fetuses

Ans. C

Explanation:

The infection is transmitted from animals to humans.

Brucella abortus (cattle), B suis(hogs), and B melitensis (goats) are the main agents.

Transmission to humans occurs by contact with infected meat (slaughterhouse workers), placentae of infected animals (farmers, veterinarians), or ingestion of infected unpasteurized milk or cheese.
 
Ref: Schwartz B.S. (2014). Chapter 33. Bacterial & Chlamydial Infections. InPapadakis M.A., McPhee S.J., Rabow M.W. (Eds), CURRENT Medical Diagnosis & Treatment 2014.

Q. 6

What is the recommended drug of treatment for brucellosis?

 A

Tetracycline

 B

Doxycycline

 C

Erythromycin

 D

Azithromycin

Q. 6

What is the recommended drug of treatment for brucellosis?

 A

Tetracycline

 B

Doxycycline

 C

Erythromycin

 D

Azithromycin

Ans. A

Explanation:

The drug of choice for treatment of human brucellosis is tetracycline.

Ref: Park 21st edition, page 266.

 


Q. 7

Regarding Brucellosis, all of these are true except‑

 A

Man to man transmission

 B

A zoonosis

 C

Blood cultures used in diagnosis

 D

B melitensis is the most common cause

Q. 7

Regarding Brucellosis, all of these are true except‑

 A

Man to man transmission

 B

A zoonosis

 C

Blood cultures used in diagnosis

 D

B melitensis is the most common cause

Ans. A

Explanation:

Ans. is ‘a’ i.e., Man to man transmission 

  • Man to man spread does not ordinarily occur, but very rarely transmision has been reported through placenta, breast feeding and sex.

.       Human brucellosis is a zoonosis, acquired from animals directly or indirectly.

.   Blood culture is most definitive method for the diagnosis of brucellosis. – Ananthanarayan 7″/e p. 349.

.   Br. melitensis is the commonest cause of symptomatic disease in humans. – Harrison 18`”/e p. 1296

.       Brucella is transmitted to humans by accidental contact with infected animal feces, urine, milk and tissues. The common sources of infection for human are :

.    Unpasteurized milk, milk products. (Most important)

.         Cheese

.         Occupational contact with infected animals e.g. farmers, veterinarians, slaughter house workers.

.         Occasionally the airborne infection may occur due to inhalation of dried material of animal origin.

.         Infection by contact occurs when brucellae in infected tissues, blood, urine, vaginal discharge, aborted fetuses and placenta enter through abraded skin, mucosa or conjuctiva (mucocutaneous route).

Note ‑

.    Erythritol has a specially stimulating effect on the growth of brucellae. Brucellae have a predilection for the placenta due to presence in it of erythritol.

.   Culture media for brucella —> Serum dextrose agar, serum potato infusion agar, Trypticase Soy agar, Tryptase agar.

.    Brucell is capnophilic (require 5-10% CO2 for growth).


Q. 8

Mode of transmission of Brucella is ?

 A

Air

 B

Water

 C

Milk

 D

Aerosol

Q. 8

Mode of transmission of Brucella is ?

 A

Air

 B

Water

 C

Milk

 D

Aerosol

Ans. C

Explanation:

Ans. is ‘c’ i.e., Milk 


Q. 9

Brucellosis can be transmitted by all of the following modes, except-

 A

Contact with infected placenta

 B

Ingestion of raw vegetables from infected forms

 C

Person to person transmission

 D

Inhalation of infected dust or aerosol

Q. 9

Brucellosis can be transmitted by all of the following modes, except-

 A

Contact with infected placenta

 B

Ingestion of raw vegetables from infected forms

 C

Person to person transmission

 D

Inhalation of infected dust or aerosol

Ans. C

Explanation:

Ans. is ‘c’ i.e., Person to person transmission 


Q. 10

A farmer presenting with fever off-and on for the past 4 years was diagnosed to be suffering from chronic brucellosis. All of the following serological tests would be helpful in the diagnosis at this state except –

 A

Standard Agglutination test

 B

2 Mercapto-ethanol test

 C

Complement fixation test

 D

Coomb’s test

Q. 10

A farmer presenting with fever off-and on for the past 4 years was diagnosed to be suffering from chronic brucellosis. All of the following serological tests would be helpful in the diagnosis at this state except –

 A

Standard Agglutination test

 B

2 Mercapto-ethanol test

 C

Complement fixation test

 D

Coomb’s test

Ans. A

Explanation:

Ans. is ‘a’ i.e., Standard Agglutination test +

.       In chronic brucellosis, 1gM often may be absent and ony Ig G can be demonstrated.

.       The standard agglutination test mainly identifies the Ig M antibody, so it is often negative in chronic brucellosis.


Q. 11

All are true about Brucella except – 

 A

B. abortus is capnophilic

 B

Transmission by aerosol can occur occasionally

 C

Paesturisation destroys it

 D

2ME is used to detect IgA

Q. 11

All are true about Brucella except – 

 A

B. abortus is capnophilic

 B

Transmission by aerosol can occur occasionally

 C

Paesturisation destroys it

 D

2ME is used to detect IgA

Ans. D

Explanation:

Ans. is ‘d’ i.e., 2ME is used to detect IgA 

2- MercaptoEthanol (2-ME) agglutination test

.  The 2ME ( 2-mercaptoEthanol) agglutination test is the most useful for differentiating active from inactive Brucellosis.

  • In this test the IgM immunoglobulin is inactivated by treating with 2-MercaptoEthanol (2-ME) which breaks the disulfide bond and depolymerizes the IgM.
  • The IgG immunoglobulin is resistant to depolymerization by 2- mercaptoethanol (2ME).
  • The depolymerized IgM does not contribute to agglutination therefore the titre is primarily due to “ME resistant antibody (IgG)”.
  • The 2ME agglutination test is most useful for differentiating active from inactive brucellosis in persons having ill defined complaint.

.   The presence of 2ME resistant (IgG) brucella agglutinins indicates active disease in these patients.

  • In addition 2ME agglutination test has been found to be superior to the routine agglutination test for determining the adequacy of antibiotic therapy.

.    Adequate therapy reduces the IgG antibody level but not the IgM antibody level. If adequate therapy is not given this infection may progress to a state of chronic brucellosis in which the serological activity is mainly due to IgG antibody.

.   A fall in 2ME resistant IgG antibody titre indicates satisfactory response to therapy.

About other options

.   Brucella is capnophilic ( requires 5-10% CO2 for growth).

  • Occasional the airborne infection ( by aerosol) may occur due to inhalation of dried material of animal origin.

.    Pasteurization destroys brucella, therefore it is transmitted by unpasteurized milk.


Q. 12

Treatment of Brucellosis –

 A

Doxycycline

 B

Streptomycin

 C

Erythromycin

 D

a and b

Q. 12

Treatment of Brucellosis –

 A

Doxycycline

 B

Streptomycin

 C

Erythromycin

 D

a and b

Ans. D

Explanation:

Ans. is ‘a’ i.e., Doxycycline; ‘b’ i.e., Streptomycin


Q. 13

Which of the following is a test for brucellosis ‑

 A

Milk ring test

 B

Stomach bowel test

 C

Rose wailer test

 D

Paul bunnel test

Q. 13

Which of the following is a test for brucellosis ‑

 A

Milk ring test

 B

Stomach bowel test

 C

Rose wailer test

 D

Paul bunnel test

Ans. A

Explanation:

Ans. is ‘a’ i.e., Milk ring test

Tests for detection of brucellosis in herds of cattle.

1) Rapid plate agglutination test

2) Rose bengal card test

Tests to detect antibodies in milk.

1) Milk ring test

2) Whey agglutination test



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