Jack C Rhyan, USDA, APHIS, VS, National Wildlife Research Center
4101 LaPorte Avenue, Fort Collins, CO 80521

General Information:

• 6 named species: B. melitensis (sheep and goats, cattle in mid East), B. suis (swine and reindeer, cattle in FL and Latin America), B. abortus (cattle, bison, and elk), B. canis (dogs), B. ovis (sheep and goats), B. neotomae (wood rats), Marine mammals brucellae

• B. melitensis discovered by Bruce "Malta fever" 1887; B. abortus discovered by Bang "Bang’s disease" 1897

• Ranges from complicated, eventually fatal disease (rarely) to fever of unknown origin; frequently assymptomatic; case fatality of 0 - 1% usually due to myocarditis.

• Transmission by contact with body fluids of infected animals, ingestion, aerosol, and (rarely) by tissue transplants or sexual contact

• Symptoms: fever, chills, night sweats, headache, arthralgia, arthritis, anorexia, nausea, weight loss, weakness, backache, abortions (rare)

• B. melitensisis principle cause of human brucellosis; clinically most severe; in USA due to ingestion of imported unpasteurized goat cheese.

• B. ovis and B. neotomae - no known human disease

Causes for "emergence" of wildlife brucellosis as disease issue:

• Currently brucellosis in USA = wildlife brucellosis

• "Ozark Mountain" emergence

• Game farming

• Increased popularity of hunting, viewing, etc.

• Urban sprawl

• Expanding range of animals (YNP, feral swine)

• Global trade

• Recent discovery (marine mammals)

Current status of domestic animal brucellosis in USA

• Bovine brucellosis - 0 affected herds

• Swine brucellosis - 0 affected herds

• 3 million feral swine in at least 24 states

• B. suis biovars 1 and 3

• Transmission: venereal, ingestion/contact with infected fetuses, placentas, fluids

• Signs/lesions: abortion at any stage of gestation, stillbirths, weak pigs, sterility, lameness, orchitis, arthritis

• Seroprevalence: 4% (CA) - 53% (FL); majority of seropositives are culture positive

• Human disease: packing plant employees, livestock owners, hunters (3 ½ weeks after cleaning wild hog)

• Spread to other species: cattle, dogs

• Current control strategies: regulations concerning transport; prevention of contact between feral and domestic swine

• Research needs: population control; safe efficacious vaccine and delivery system

• Reindeer: 14 herds on Seward Peninsula totaling 20,000 reindeer (1997); caribou: several hundred thousand in western arctic herd

• B. suis biovar 4

• Transmission: ingestion/contact with infected fetuses, placentas, fluids; venereal(?)

• Signs/lesions: abortion, retained placenta, lameness, sterility, orchitis, epididymitis, seminal vesiculitis, metritis, mastitis, nephritis, bursitis/synnovitis

• Seroprevalence: reindeer - cyclic - <1% - >20%; caribou - 1% - 24%

• Human disease: 5 - 20% are seropositive where caribou is eaten

• Spread to other species: dogs, foxes, wolves, bears, muskox, moose, cattle (experimentally)

• Prevention strategies: 2/3 of AK herds are vaccinated ( killed vaccine);

• Research needs: safe efficacious vaccine and delivery system

• 120,000 elk in GYA; 25,000 winter on 23 feedgrounds

• B. abortus biovars 1 and 4

• Transmission: ingestion/contact with infected fetuses, placentas, fluids

• Signs/lesions: abortion, stillbirth, bursitis, arthritis, hygromata

• Seroprevalence: feedground elk - 24%; nonfeedground elk - <2%

• Human disease: rare

• Spread to other species: bison, cattle, horses, bears, moose(?), canids(?)

• Prevention strategies: ballistic vaccination with Strain 19, habitat improvement

• Research needs: safe efficacious vaccine and delivery system; RB51(?), oral vaccination(?); habitat management strategies

• 3300 bison in YNP and GTNP

• B. abortus biovars 1 and 2

• Transmission: ingestion/contact with infected fetuses, placentas, fluids; milk; venereal(?)

• Signs/lesions: third trimester abortion, stillbirth, weak calves, retained placentas, arthritis, bursitis, hygromata, orchitis, epididymitis, seminal vesiculitis, metritis

• Seroprevalence: 50% (YNP); 70% (GTNP); 46% of seropositives are culture positive

• Human disease (?)

• Spread to other species: cattle, elk, bears, canids, moose(?)

• Prevention strategies: historically - strain 19 vaccination and test and slaughter

• Reseach needs: RB51 efficacy studies; adult vaccine safety studies; nontarget studies; delivery systems; studues related to management plan

• B. maris(?), B. delphini(?); lumpers vs splitters; probably several species

• Transmission: ?, fecal shedding

• Signs/lesions: abortion with placentitis (bottlenose dolphin), subcutaneous lesions (harbor porpoise, common dolphin, striped dolphin)

• Seroprevalence: ringed seal (4 - 40%); Atlantic walrus (12%); grey seal (23%); harbor seal (32%); harbor porpoise (22%); common dolphin (1 of 1); striped dolphin; bottlenose dolphin; killer whale; pilot whale; hooded seal (35%); harp seal (2%); minke whale (8%); fin whale (11%); sei whale (14%); California sea lion 5 of 89 (5.6%)

• Culture positive: harbor seal, harbor porpoise, common dolphin, bottlenose dolphin, hooded seal, grey seal, Atlantic white-sided dolphin, European otter, minke whale

• Human disease: ? (1 case in laboratory worker)

• Spread to other species: ? (cattle-experimental inoculation caused seroconversion and abortion)

• Prevention strategies: ?

• Emerging disease: earliest report was in 1994

• Research needs: surveillance, pathogenesis and epidemiology.

• Corbel MJ. 1997. Brucellosis: an overview. Emerging Infectious Diseases 3: 213-230.

• Moore CG, Schnurrenberger PR. 1981. A review of naturally occurring Brucella abortus infections in wild mammals. J Am Vet Med Assoc 179: 1105-1112.

• Davis DS. 1990. Brucellosis in wildlife. In: Nielsen K, Duncan JR eds. Animal Brucellosis. CRC Press. Boca Raton, FL. pp. 322-334.

• Rhyan JC. 2000. Brucellosis in terrestrial wildlife and marine mammals. In: Brown C, Bolin C eds. Emerging Diseases of Animals. ASM Press. Washington, D.C. pp.161-184.