Download What Are the Symptoms of Brucellosis?

Brucella
Dr. Batool
Brucellosis : Is a zoonotic infection caused by the bacterial
genus Brucella. The bacteria are transmitted from animals to
humans by ingestion through infected food products, direct
contact with an infected animal, or inhalation of aerosols.
General characters:
-Brucellae are Gram-negative.
-Coccobacilli (short rods), intracellular.
-Non-spore forming.
-Lack capsule.
-Lack flagella and, therefore, are non-motile.
-They are aerobes but some species require an atmosphere with
added CO2(5-10%).
-Multiplication is slow at the optimum temperature of 37°C and
enriched medium is needed to support adequate growth.
-Catalase, oxidase and urease are positive.
-The colonies of smooth strains are small, round and convex,
with loss of the O chains of the LPS, occurs readily to form
rough or mucoid variants.
These latter forms are natural in B. canis and B. ovis as the
LPS of these lack O chains.
Many Names of Brucellosis:
- Malta fever
- Undulant fever
- Gastric fever
- Mediterranean fever
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Brucella
Dr. Batool
Brucella Species:
B.melitensis.
B.abortus.
B.suis.
B.canis.
Transmission in animals:
 Zoonosis affecting domestic animals.
 Concentrated in milk, urine and genital organ of animals.
Routes of Transmission in human:
 Oral: Unpasteurized milk and products raw milk, or
rarely through undercooked meat.
 Respiratory: lab workers and stables.
 Skin: accidental penetration, or broken skin on contact
with infected (tissue, blood, urine).
 Other routes: Blood transfusion, transplacental ,
conjunctival, rarely person to person.
Virulence:
Intracellular pathogen that is resistant to killing by
phagocytes.
Antigenic Structure and Classification:
- A and M antigen are common to 3 mains Brucella spp.
- B. melitensis has the highest concentration of M
antigen and causes the most serious infections.
- The difference between species is related to the amount
of the two main antigen:
 B.abortus:
A:M=20:1
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Brucella
Dr. Batool
 B.melitensis:
A:M=1:20
 B.suis
A:M=2:1
Other Virulence Factors:
 Superoxide dismutase.
 Catalase
 Urease
 Cytochrome oxidase
 Brucella virulence factor A
 Brucella virulence factor B
Pathogenesis:
- Incubation period: 10-30 days.
- Enter the body through:
the mouth, conjunctivae, respiratory tract and abraded
skin.
Followed by entry, ingested by polymorphonuclear and
not killed (as a result of presence superoxide dismutase,
LPS).
- Spread to local lymph node, multiple and spread to
blood reaches to (RES) reticuloendothelial sites (spleen, liver,
other lymph node).
- Resist phagocytosis (production of AMP/GMP and TNF
inhibits the phagosomalfusion).
-Spread (CNS, heart, joint, respiratory, skin).
What Are the Symptoms of Brucellosis?
General symptoms of brucellosis are often vague and similar to
the flu. They may include:
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Brucella
Dr. Batool
 Fever (the most common symptom, with high "spikes" that
usually occur in the afternoon)

Headache

Night sweats

Weakness

Back pain

Body-wide aches and pains

Poor appetite and weight loss

Abdominal pain

Cough
Symptoms usually appear within 5 to 30 days after you come
in contact with the bacteria.
How bad your symptoms are depends on what type
of Brucella is making you sick:

B. abortus usually causes mild or moderate symptoms, but
they are more likely to become chronic (long-lasting).

B. canis symptoms may come and go. They are similar
to B. abortus infection, although people with B. canis often
have vomiting and diarrhea.

B. suis may cause areas of infection (called abscesses) in
different organs.

B. melitensis may cause sudden and severe symptoms,
which may lead to disability.
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Brucella
Dr. Batool
Complications:
Severe brucellosis may cause:
 Infection of the central nervous system
 Endocarditis (infection of the lining of the heart or valves)
 Liver abscess
Brucellosis can cause long-lasting symptoms that are similar to
systemic exertion intolerance disease. SEID is formerly
Chronic Fatigue Syndrome. The symptoms can lead to:

Fatigue

Fevers that come and go

Joint pain
Brucellosis in a pregnant woman may lead to:
Miscarriage
Birth defects in the baby
Death from brucellosis is uncommon. Most brucellosis-related
deaths are due to endocarditis.
Diagnosis:
1- Isolation of organism from (blood, bone marrow,
other tissues) on Blood culture is the method of choice
but specimens need to be obtained early in the disease
and cultures may need to be incubated for up to four
weeks.
2- Serum agglutination test.
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Brucella
Dr. Batool
3- Immunofluorescence method.
4- PCR, ELISA.
5- Brucellin Skin test. (using heat killed bacteria or
their extract (Brucellin or Brucellergin) give +ve test
in 3-6 weeks of the disease due to the production of
delayed type of hypersensitivity, but +ve reaction
indicates (past or present infection).
How is Brucellosis Diagnosed?

A swollen liver

Swollen lymph nodes

A swollen spleen

Unexplained fever

Joint swelling and pain

A rash
Blood tests will be done to diagnose the infection and
determine what type of Brucella is making you sick.
How Is Brucellosis Treated?
Brucellosis can be difficult to treat. Antibiotics commonly used
to treat brucellosis include:

Doxycycline

Streptomycin

Ciprofloxacin.

Rifampin
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Brucella
Dr. Batool

Tetracycline
You will generally be given doxycycline and rifampin in
combination for 6-8 weeks. With cotrimoxazole replacing
doxycycline in children.
You must take the antibiotics for many weeks to prevent the
disease from returning. The rate of relapse following
treatment is about 5-15% and usually occurs within the first six
months after treatment.
Recovery: can take weeks, even months. Patients who receive
treatment within one month of the start of symptoms can be
cured of the disease.
How Can I Prevent Brucellosis?
Brucellosis may be prevented with the following steps:

Do not drink or eat unpasteurized dairy products.

Wear rubber gloves if you work in the animal processing
industry.

As well as by comprehensive campaigns to eradicate the
disease by destroying domestic animals which exhibit
positive serologic reactions to Brucella .

Vaccines providing some protection to cattle, sheep and
goats are available.
There is no effective human vaccine to prevent
brucellosis.
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Brucella
Dr. Batool
References:
1- Jawetz, Melnick, & Adelberg’s.( 2013). Medical Microbiology (Twenty-Sixth Edition).
2- Kenneth Todar. (2008).Todar’s Online Textbook of Bacteriology
,University of Wisconsin.
3- Ray, C.G., ed. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill.
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