Each Brucella species is associated most often with certain hosts B. abortus usually causes brucellosis in cattle, bison and buffalo. B. suis is the most important species in swine. B. melitensis is the most important species in sheep and goats, B. ovis can also cause infertility in rams. B. canis causes disease almost exclusively in dogs Most species of Brucella can infect animals other than their preferred hosts
No classical virulence factors • Exotoxins (Clostridium, E. coli ,Staph aureus) • Cytolysins (listeriolysin from listeria phagosome -cytoplasm of the cell) • Capsules (Streptococcus- resistant to phagocytic action, complement fixation, antibody ) • Fimbria (Salmonella attach to (colonize) tissues, resist attack by phagocytic cells) • Plasmids (Salmonella, antibiotic resistant) • lysogenic phages (Vibrio cholerae, CTX phage cholerae toxin) • Endotoxic lipopolysaccharide (LPS) (Neisseria and E. coli) • Invasion (Yersinia and Salmonella non phagocytic cells) • (Drug resistant forms, antigenic variation) • LOV (light, oxygen and voltage) • 2x Urease genes • Preventing phagosomal-lysosomalfusion • Superoxide dismutase • Catalase • Alkyl hydroperoxidereductases (ahpC & ahpD) • Nitric oxide reductase (norD) • Base excision repair (BER)- xthA • Sidrophores • Type IV secretion system Seleem et al., 2008
Transmission • Contact (placenta, fetus, fetal fluids and vaginal discharges, urine from an infected animal). • Ruminants are usually asymptomatic after their first abortion, they become chronic carriers, and continue to shed Brucella in milk and uterine discharges during subsequent pregnancies. • venereal transmission Brucella species are also found in semen. Males can shed these organisms for long periods or lifelong. • Ingestion: Brucella can be spread on fomites including feed and water. • Inhalation: Brucella can be transmitted in aerosols.
Abortion Disease in Animals cattle, sheep, goats, swine, dogs and camel second half of gestation with retention of placenta Birth of dead or weak calves/lambs/kids and low milk yield Epididymitis, orchitis, prostatitis B. ovis and B. canis Orchitis Normal
Horses Fistulous Withers and Poll Evil inflammation of supraspinous or supra-atlantalbursae Hygromas Brucellosis, Hygromas on the knee joints of cattle
Clinical sings in dogs Dogs who are B .canis positive shed a LOT of organisms in urine and all in-contact dogs are at risk • Susceptible to • B. canis, B. melitensis, B. abortus, and B. suis • B. canis causes abortions (1-19% prevalence in the US) – Breeding kennels • Last trimester of pregnancy • Prolonged vaginal discharge • Bacteremia • Failure to conceive, stillbirths, prostatitis, epididymitis,
Diskospondylitis (infection of the intervertebral disk) signs that vary from depression and weight loss to paralysis. • Staphylococcus intermediusis the bacterial species that most often causes diskospondylitis in dogs. • Streptococcus species • Brucella canis • Escherichia coli Budsberg, S.C., 1990
Zoonosis • Five out of the nine known Brucella species can infect humans and the most pathogenic and invasive species for human is B. melitensis, followed in descending order by B. suis, B. abortusand B. canis. • B. melitensis, B. suis and B. abortus are listed as potential bio-weapons (Category B) by CDC. • Humans can get infected via contact with infected animals or consumption of their products, mostly milk and milk products especially cheese made from unpasteurized milk of sheep and goats and rennet from infected lambs and kids. Some specific occupational groups including farm workers, veterinarians, ranchers, and meat-packing employees are considered at higher risk (Inhalation, Lab acquired infection)
Most commonly acquired lab infection Seleem et al 2009 Self-inoculation by veterinarians is widespread. WHO 2006. Professional hazard 14.23% in India
Diagnosis • Isolation of organism • Blood, semen, other tissues • Serology • Brucellosis agglutination tests (card test, slide test), ELISA • Brucella milk ring test • Demonstration by fluorescent antibody of organism in clinical specimen • Placenta, fetus • PCR
Brucella vaccine In February 1996, RB-51 became the official vaccine in cattle
Brucellosis is a reportable disease Treatment • Humans are treated for 2 months with doxy and strept or doxy and gentamicin (relapse rates are high) • Treatment not an option for farm animals because of cost, lack of effective cure, eradication failure!!!
We work with a small breed rescue group who does amazing things with limited funds. The group is contempating fostering a 5 Y/O female Shih Tzu who had some vulvar discharge and tested positive for Brucellosis. The dog has since been spayed and has been treated with medication (unknown what at this time). The rescue group is concerned if there is likely to be any residual infection and if the dog would be contagious to any of the numerous rescue dogs still in the foster homes. I discussed what Brucellosis does with breeding dogs but was uncertain of their question. Any advice would be appreciated. IF the dog truly had B. canis she is considered infected for life. Her therapy will require lifetime monitoring and treatment and she should not have contact with other dogs, nor should other dogs be brought onto property where she resides. Any other in-contact dogs should be quarantined until all are negative for three monthly tests in a row.
Brian Griffin 7 years old Labrador Retriever with lumbar pain and marked right hip pain Came positive for Brucella zoonotic risk for children, elderly and immunosuppressed
People who choose to keep B. canis infected dogs must realize that lifelong monitoring with (expensive) testing and (expensive) treatment, along with isolation of the dogs and no introduction of new dogs, is going to have to happen.It is also important to realize that B. canis is a reportable disease in many states--if you don't know about your state, contact the state vet's office and find out. If it is, they will take over management and the owners will have to follow their decisions. You might put these risks in writing and have them sign. You might also want to have them consult their physician or an infectious disease MD.
Dog With Diskospondylitis And Epididymitis 4yr old Great Dane/ Labrador mix Presented today for lameness with mild weight loss and slow to rise. prominent dorsal spinous processes, pain upon palpation of lumbar spine Serology for B. canis is indicated in any dog with diskspondylitis B. canis positive for RSAT rapid slide agglutination test
What To Do In Confirmed Cases Of Brucellosis In Dogs? Experts do recommend euthanasia, and if owners opt not to that there is a long road of testing, treatment, and relapse that can put an owner at risk of infection. So I don't recommend euthanasia across the board, but the owners need to be aware of the advantages/disadvantages of keeping an infected dog. B. canis is a zoonosis. I would be inclined to put in writing the zoonotic risks as well as instructions for care and follow up and have the owners sign this.
It takes only 10 seconds http://www.ratemyprofessors.com/ Mohamed Seleem