BRUCELLOSIS

Navies 2011

Brucella

The causative agent of Brucellosis Zoonotic disease in food animals

More prevalent in developing countries A genus of Gram-negative rods -

coccobacillus Found in 7 different species

B. canis (canine) B. abortus (equine & bovine) B. melitensis B. neotomae B. ovis B. suis

Etiology

• Caused by Brucella canis– Gram negative bacteria– Causes abortions,

usually in third trimester of pregnancy

– Dogs are the definitive host

• Considered a zoonotic bacteria– Human infections are

rare– Caution when handling

aborted animals

Brucella canis rods

History of disease

Thought to exist since Roman times

In 1887 Dr. Bruce isolated the organism (hence Brucellosis)

In 1966 Brucella Canis was identified as the causative agent of canine brucellosis

B. canis

Transmitted through ingestion/ inhalation Bacterium can be found in:

lymphatic system genital tract eye kidney intervertebral disks spleen

Small red coccobacillus in clumps Associated conditions:

Infertility Abortions Diskospondylitis

B. canis

Signalment Non breed specific Affects males/ females

Sexually mature 5-12mos. Of age

B. canis

Clinical Signs: Scrotal swelling/dermatitis Enlarged epididymis Testicular atrophy

Abortion Infertility Vaginal discharge

1-6 wks postabortion

B. canis

Clinical Signs:• Primary sign is abortion

in last trimester of pregnancy, followed by prolonged vaginal discharge

• Infected dogs may develop generalized lymphadenitis

• Epididymitis• Periorchitis• Prostatisis• Spondylitis and uveitis

are occassional complications

Enlarged Epididymis

B. canis

Transmission:• Can easily penetrate any mucous membrane

– Oral, conjunctival or venereal• Infection though oral route is the most common

though ingestion of infected material• In a pregnant female the organism goes

though the uterus and causes a late abortion– After the abortion, vaginal discharge and the

aborted material contain a large number of the bacteria

– In males, the urine and semen is where large numbers of bacteria are found

Diagnostic tests and expected results Isolated from vaginal exudate, aborted

puppies, blood, milk, semen Simplest test is Rapid Slide

Agglutination Test to look for antibodies against disease

B. canis

Diagnosis:• Isolation and identification of the bacteria is the

only way to diagnose the disease– Organism can be isolated from:

• Vaginal exudate• Aborted puppies• Blood (it takes up to 3 weeks to be detected in blood

stream)• Milk• Semen

• Widely used tests are agglutination test by tube or slide method

• Agar gel immunodiffusion tests used in some laboratories

B. canis

Recommended Treatment:• Usually unsuccessful and not recommended

to eliminate the organism• Long term antibiotics used and show some

promise• Animals treated may remain infected after

treatment• Doxycycline and an aminoglycoside• Tertacycline and streptomycin• Minocycline and streptomycin

B. canis

Prognosis: Animals can naturally heal but may take

up to five years Relapses can occur and symptoms may

occur for several years

B. canis

Prevention: Animals with brucellosis should be

neutered/spayed In large kennels/ shelters daily use of

Roccal will kill the bacteria Keep new animals quarantined before

introducing them to other canines.

Facts

Not common in US; about 100-200 cases each year

More common in countries with no good standardized and effective public health and domestic animal programs, like South and Central America, E. Europe, Asia, Africa

No vaccine in humans Also known as Canine STD

Swine

Brucella suis

B. suis

• Etiology:• Caused by Brucella suis

– Spread by ingesting infected tissues or fluids

– Highest prevalence among feral pigs

– Can remain in some herds for years

• Considered zoonotic– Humans come in contact with

bacteria through:• Laboratory work• Farming• Herding• Veterinary work• Though contact with infected

animals or tissues

Brucella suis

B. suis

Signalment: B. suis has no specific signalment Pigs that are used for breeding do have

a high risk of contracting the bacteria

B. suis

Transmission:• Pigs that are raised for breeding are a source

of infection– Suckling pigs may become infected by means of

mother, but most reach weanling age without becoming infected

• Can be transmitted by ingestion of feedstuffs that are contaminated by birth and/or abortion products and uterine discharges– Pigs will eat aborted fetuses and membranes

• Transmission can occur during copulation or artificial insemination

B. suis

Clinical signs:• After exposure to bacteria, pigs develop a bacteremia

that may persist for up to 90 days– Localization to various tissues may occur during or after

bacteremia• Abortion• Temporary or permanent sterility• Orchitis• Lameness• Posterior paralysis• Spondylitis• Metritis• Abscess formation

B. suis

Diagnosis: Card test (most accurate) Serum agglutination tests Complement fixation tests

Entire herds of pigs must be tested rather than individual pigs

B. suis

Recommended Treatment: No vaccine for Brucella suis No recommended treatment Control of transmission is based on test,

cull(segregation), and slaughter of infected pigs

B. suis

Prognosis: Can be eradicated from infected herds

by means of: Depopulation Tests and removal methods Quarantine of infected herds

B. suis

Prevention: Keeping domesticated swine herds from

coming in contact with wild and feral swine

Test herds and not breeding swine that are infected

Quarantine swine purchased in fairs or other sources until testing can be done

B. suis

Client Education: Perform regular testing of herds Purchase swine from reputable sellers Keep those that are infected in isolation

and do not use for breeding Test semen that will be used for

insemination prior to insemination

Bovine

Brucella abortus

B. abortus- Bovines

History: 1895- Bang in Copenhagen isolated the organism

Brucella abortus and proved that it caused abortions in cattle "Bang's abortion” 1917- Yellowstone Nat’l Park documented brucellosis

among the bison herd. 1956- Due to a $1 billion eradication program, only

the ‘Triple U’ buffalo herd and five infected private cattle herds in Texas and Missouri still harbor brucellosis.

B suis or B melitensis has also rarely been implicated in some cattle herds.

B. abortus- Bovine

Signalment: Males & females Any age or breed

B. abortus- Bovine

Transmission: Occurs by ingestion of organisms

Can be present in: aborted fetuses fetal membranes uterine discharges contaminated feed/water

licking contaminated genitals of other animals artificial insemination when contaminated

semen is deposited in the uterus

B. abortus- Bovine

Clinical Signs: abortion is the most obvious sign!! weak or stillborn calves reduced milk production retained placentas agglutinins in the seminal plasma testicular abscesses in infected bulls arthritis may result from longstanding

infections

B. abortus- Bovine

Diagnostic Tests: Herds: bang test/ Brucellosis ring test:

Herd’s milk and test for agglutination Serum agglutinin tests are the standard

method of diagnosis A complete agglutination at a dilution of 1:100

or more is positive for brucellosis in non vaccinated animals.

1:200 is positive for animals vaccinated between 4 to 12 months of age.

B. abortus- Bovine

Treatment: Treatment for brucellosis of cattle is not

permitted ALL infected cattle and contacts which have

been exposed to infection must be slaughtered.

B. abortus- Bovine

Pathological lesions: granulomatous inflammatory lesions are

present during a necropsy Lesions may be present in:

the reproductive tract udder supramammary lymph nodes joints synovial membranes.

Vaccination

The vaccine is a live product and must be administered only by an accredited veterinarian or State or Federal animal health official.

Brucella vaccine, called Strain RB51, for use in cattle

Female calves should be vaccinated when they are 4 to 6 months old.

At the time of vaccination, a tattoo is applied in the ear; that tattoo identifies the animal as an "official vaccinate." The tattoo identifies the year in which vaccination took place.

Equine

Brucella abortus

B. abortus- Equine

Reported sporactically in the US over the last 70 yrs

Declined in prevalence due to the Brucellosis Cattle Eradication program

Higher infection rates in: Texas Florida Alabama Louisiana

B. abortus- Equine

Signalment: All breeds Males & females No age descrimination

B. abortus- Equine

Clinical Signs: Most commonly manifests as fistulas

located in the withers of the horse A source of exposure to humans

Late term abortions Non-specific lameness due to joint

infections ‘poll evil’

B. abortus- Equine

Prognosis/ Diagnosis Unlike B. abortus in cattle, no specific Equine

Brucellosis eradication program has ever been implemented.

Samples of infection sites are obtained for cultures

B. abortus is difficult to isolate, so horse must also be tested for evidence of anitbodies to B. abortus.

Titers (plate agglutination) greater than or equal to 1:50 is considered + for this bacteria.

B. abortus- Equine

Prevention: Neuter/cull infected animals Quarantine & testing all new animals

especially breeding stock

Brucellois in Humans

Humans can become infected by coming in contact with infected animals or animal products that are contaminated with this bacteria. Eating/drinking the organism Inhalation of the organism (least common) Through open skin wounds

Slaughterhouse & meat packing plant employees, and hunters are at a higher risk

Direct person-to-person spread is rare but can occur through breast milk, and sexual contact

Brucellosis in Humans (Undulant Fever)

Zoonotic cases mostly occur: in countries where animal disease control programs

are in-efficient or non existent Countries that do not have standardized & effectie

public health & domestic animal health programs. DO NOT EAT: un-pasturized dairy

products!!!!!!!! NO vaccine available for humans Mortality is low (less than 2%) & is usually

associated with endocarditis. Wear gloves when handling new animals canines &

food animals) and beware of bodily fluids!

Brucellosis in Humans

Causes a wide range of symptoms: Fever Sweats Headaches Back pains Physical weakness Severe infections of the CNS or lining of the

heart may occur Can also cause long- lasting, chronic

symptoms that include: Recurrent fevers, joint pain & fatigue

References Veterinary Technician’s Daily Reference Guide: Canine and Feline. 2nd Edition (pg.

130, 256-258).

Saunders Comprehensive Veterinary Dictionary 3rd Edition. (pg. 256).

http://www.cfsph.iastate.edu/Factsheets/pdfs/brucellosis_abortus.pdf

http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/110502.htm

http://www.merckvetmanual.com/mvm/index.jsp

http://www.greenlewis.com/articles/canine-brucellosis.php

http://www.marvistavet.com/html/brucellosis_in_dogs.html

http://www.infectiousdiseasenews.com/article/40915.aspx

References continued…

• http://www.merckvetmanual.com/mvm/index.jsp• http://www.greenlewis.com/articles/canine-

brucellosis.php• http://www.marvistavet.com/html/

brucellosis_in_dogs.html

• http://www.infectiousdiseasenews.com/article/40915.aspx

www.peteducation.com www.Vetinfo.com www.Medicinenet.com www.cfsph.iastate.edu/Factsheets/

pdfs/brucellosis.pdf