Brucella Species
When would a titer show a positive result for Brucella canis?
- 8-12 weeks post infection
What is the preferred site of replication for Brucella species
- Animal uterus - Placenta - mammary gland - testicles
What are hosts of Brucella suis other than natural host?
- Cattle - Dog - Man
Natural host of Brucella melitensis
- Goat - Sheep
how does Brucella melitensis present itself?
- Late term abortion - still births
Natural host of Brucella canis
- dog - other canids
What are common manifestations of Brucella species?
- placentitis - endometritis - mastitis - orchitis
How are commercial herds exposed to Brucella suis
Feral swine
How is Brucellosis diagnosed?
Serological tests - Titers - Mercapteothanol rapid slide agglutination test (ME-RSAT)
Is Brucell aerobic or anaerobic?
aerobic
What is Poll evil?
an inflammation/ abcess between the ears which become fistulated
What is fistulous withers
an inflammation/ abscess of supraspinous bursa ( overlying 2nd - 5th thoracic vertebrae) which become fistulated
What are some LPS mutations the basis for?
attenuation and are basis for vaccine strain
Why is owning a B.canis infected dog a potential risk?
- B.canis is zoonotic
What are hosts of Brucella aborus other than natural host?
- Bison - Sheep - Goat - Elk - Horse - Dog - Man
what two strains of Brucellosis are seen in small ruminants
- Brucella melitensis - Brucella ovis
How does Brucellosis spread from heard to heard?
- By an infected animal - Wild animals (bison/ elk) transmit to cattle
what are Brucella species pathogenic features?
- Endotoxin (LPS) - Facultative intracellular pathogen of macrophages - inhibition of phagosome fusion with lysosome fusion - replicates intracellularly in phagosome
How does Brucella Ovis present itself?
- Epididymitis in ram most common - Rarely late abortions in ewe, stillbirths
Brucellosis in Horses
- Fistulous withers - Poll evil - both uncommon in U.S.
Symptoms of Undulant fever
- Flu-like - intermittent fever of variable duration - Malaise - anorexia - headache - muscle pain - back paint - signs may go away and return months later - causes orchitis and epididymiteis in males but can infect any organ - pregnant women generally do not abort
Clinical Disease: Canine brucellosis in famales
- May fait to conceive - may abort 45-60 days gestation or give birth to stillborn or weak pups - brown to greenish-gray vaginal discharge persist 1-6 weeks after aborting - Discharge has LOTS of organisms (100 million/mL)
What countries are affected by Brucella Melitensis?
- Mediterranean countries - central and south America - not in USA now
- What is the ME-RSAT?
- Mercaptoethanol rapid slide agglutination test - inexpensive, quick in-house test for vets (Brucella canis) - uses dyed-killed whole B.canis cells - False positives may occure due to cross-reactive antibodies present in sera of normal dogs (anti-LPS antibodies) - A positive test should be confirmed by ELISA or agar ge immunodiffusion test
What specie are affected by Brucella melitensis?
- Natural host in goats and sheep - can infect pigs, cattle, dogs and humans
What are hosts of Brucella melitensis other than natural host?
- Pig - Cattle - Dog - Man
What organisms cause Canine Brucellosis?
- Primarily B. canis - rarely B. abortus & B. suis
How is canine Brucellosis transmitted?
- Primarily by oral or nasal mucous membrane - contact with aborted materials - urine - infected semen
How is Brucellosis in horses diagnosed?
- Serum agglutination should be performed - Horses do not show infertility or abortion
Who are the hosts of Brucella suis
- Swine - humans - cattle - dogs
Cllinical Disease: Canine brucellosis: Male
- Swollen lymph nodes - enlarged scrotum with scrotal dermatitis from constant licking - epididymitis - decreased sperm volume and motility (abnormal sperm: bent tail, headless, agglutination of heads) - Many inflammatory cells, sperm phagocytosis - Brucella canis may be present in sperm
What are the treatments for Bovine Brucellosis?
- There is no treatment - Can't cure - Clinical signs may disappear but animal is still infected
How are Brucella species transmitted?
- Usually occurs via direct contact of mucous membranes with infected secretions, infected tissues, infected semen, infected milk or fomites contaminated with . secretions. - Can occur by inhalation of aerosols - Can occur by ingestion
what are the control measures of Brucellosis in Cattle?
- Vaccination (65% effective) - good sanitation, disinfect calving areas - * replacement stock should be tested prior to purchase - * replacement should be quarantined 60 days and retested before allowing to join herd
Is there a vaccine for Brucellosis?
- Yes - Calfhood vaccination with strain RB51 (LPS attenuated mutant)
Discospondylitis
- a canine brucellosis infection of vertebrae and intervertebral disk - signs include spinal pain, weakness, ataxia
What are the signs of Brucellosis in cattle?
- abortion 5th-7th month of gestation - stillbirths - weak calves - retained placenta - Orchitis and epididymitis in bulls - fever of unknown origin - enlarged joints - Bacteria in aborted fetus, placenta, genital discharge, milk
How does Brucella suis present itself?
- abortions - stillbirths - metritis - orchitis - spondylitis - arthritis
Chronic Canine Brucellosis in males
- atrophy of testicles - less sperm phagocytosis and agglutination - inflammatory cells and B.canis bacterial numbers decreased in sperm - Total sperm numbers are decreased.
How is Brucella suis diagnosed?
- card test - culture/ PCR of placenta, clood stomach content of fetus
Low antibody titers are seen in what kind of dogs?
- chronically infected dogs
How is brucellosis in humans transmitted?
- contact with infected secretions, urine or tissues - enters via mucous membranes and abrasions on skin - inhalation of aerosol while cleaning infected animal pen or slaughterhouse - ingestion of unpasteurized milk/cheese - person to person transmission is rare
How is bovine brucellosis diagnosed?
- culture - PCR of organism from infected tissues, blood and/or stomach contents of aborted fetus - serological card test/ serum agglutination test
how would a human contract B.canis
- dog owners and breeders through contact with aborting bitches (most common) and infected males
how would a human contract B.abortus
- from exposure to bocine abortions, tissues, milk
When should blood be cultured?
- if a dog tests positive on serological test - may be negative - culture of org. from blood, urine, tissue is confirmative
what is a common complication of undulant fever?
- infection of cone and joints in about 40% of cases
Why treatment failures or relapses common with B.canis despite antibiotic sensitivity?
- intracellular nature of infections - Serological test should be repeated: continued high titers indicative of ongoing infection
Prevention and control of Canine brucellosis in breeding animals
- isolate suspect animal - kennel should be quarantined when diagnosis of B.canis obtained - confirmed infected dogs should be eliminated as breeders (neutered treated, and removed to different locations) - Kennels and equipment must be disinfected - remaining dogs should be serologically monitored ) monthly for 3 mo) - male dogs should undergo sperm evaluation
Why are there ~ 100 cases in US anually
- most cases associated with consumption of foreign unpasteurized cheese
how would a human contract B.melitensis
- mostly foodborne - consumption of unpasteurized goat milk and cheese
Treatment of Canine Brucellosis for pet dogs
- neutering to reduce shedding - Long-term therapy (90+ days) with more than one drug
How is Brucella suis controlled?
- no vaccine - sell stock for slaughter
Who is susceptible to undulant fever?
- occupational disease of farmers - vets -slaughter house workers - lab workers - kennel workers - hunters
Through what surface can an animal become infected with Brucella species?
- oral mucous membrane - nasal mucous membrane - genital mucous membrane - conjunctival mucous membrane
Pathogenesis of Brucella species?
- phagocytosed by macrophages and carried to lymph nodes - Bacteremia develops and bacteria spread to other nodes, many organs including uterus, udder, epididymis, testes
What happens if a blood or milk ring test show positive results?
- regulatory vet is contacted - individual cows in herd are tested - If positive, herd is quarantined and positive animals depopulated (culled)
Brucellosis eradication program
- started in 1954 with 124,000 B. abortus infected in USA - Through testing, herd quarantine and slaughter, in 2019 Puerto Rico, Virgin Islands, and all states but MT are Brucellosis Free
Why is MT not Brucellosis free?
- there are free ranging bison and elk at Yellowstone National Park, a large percentage of which are positive for B. abortus - A major concern is the threat of cattle being exposed
Where is Brucella normally found in infected animals?
- vaginal secretions - semen - aborted fetus - placenta - urine - blood - milk - lymph nodes - other organs
When might repeat treatment be necessary
- when dogs have skeletal disease, often unrewarding
would PCR be helpful in diagnosing?
- yes
National Brucellosis elimination program
A large percentage of dairy and beef cattle are blood tested at slaughter
What is the primary agent responsible for Brucellosis in horses?
B. abortus
What Brucella species affects cattle
B.abortus
name of clinical disease of Brucellosis in swine
Brucella suis
What species is specific to canine brucellosis?
Cats
What is the natural host for Brucella abortus?
Cattle
What is the reservoir agent for brucellosis in Horses?
Cattle
Gram stain characteristics and major morphology of Brucella
Gram-negative; Coccobacilli
How has Texas and the Greater Yellowstone Region responded to the possibility of exposure of cattle to Brucellosis from wild Elk and Bison
Greater amount of blood testing done at slaughter
What additional precautions do some individual states choose to perform to ensure that Brucellosis is not present?
Milk Ring Test of bulk tank milk
is there a vaccine for canine brucellosis in dogs?
NO
Can Brucella replicate outside of host?
No
Do all dogs show clinical signs of canine Brucellosis?
No, despite generalized infection, many dogs don't show clinical signs
What species is affected by Brucella ovis?
Only sheep
If present, what are overt signs of Canine brucelllosis?
Reproductive problems in sexually mature animals
Natural host for Brucella Ovis
Sheep
What is the Milk Ring Test?
Stained killed B. abortus organisms mixed with milk. Agglutinates if antibodies are present in milk and forms blue ring in at cream line
Natural host of Brucella Suis
Swine
What is brucellosis?
The disease caused by Brucella
What is Brucellosis in humans called?
Undulant fever
What is serum agglutination test?
Uses serum and stained killed B. abortus and identifies serum antibody by visible agglutination
how would a human contract B.suis
farmers and slaughterhous workers and especially hunters exposed to infected swine
Is B.Canis reportable
if the dog was recently obtained from breeder, pet shop or shelter?
where can Brucella survive in environment outside of host?
in abortive tissue and genital tract secretions
What are hosts of Brucella ovis other than natural host?
none
What are hosts of Brucella canis other than natural host?
occasionally man
Is Brucellosis in humans reportable?
yes
Is Brucella infection reportable?
yes, in any species
