Brucellosis

Table of Contents

Disease Information

Overview

Potential Bioterrorism Agent: Category B

Also known as:  Undulant Fever, Malta Fever, Mediterranean Fever                               

Responsibilities

  • Hospital: Report immediately by phone if bioterrorism suspected, otherwise within 3 days
  • Lab: Report immediately by phone if bioterrorism suspected, otherwise within 3 days
  • Physician: Report immediately by phone if bioterrorism suspected, otherwise within 3 days

Local Public Health Agency (LPHA): Follow-up required.  Iowa Department of Public Health will lead the follow-up investigation.

Iowa HHS
Disease Reporting Hotline: (800) 362-2736
Secure Fax: (515) 281-5698

A. Agent

Brucellosis is caused by Brucella bacteria. The species of Brucella which infect humans are B. abortus, B. melitensis, B. suis, and rarely, B. canis.

B. Clinical Description

Symptoms: May be non-specific, including sustained or irregular fever of variable duration, headache, weakness, sweats, chills, arthralgias, malaise, weight loss, depression and generalized aching.

Onset: May be acute or insidious. Localized infections of organs (including the liver and spleen) and chronic localized infections can occur. The disease may last for days, months, or occasionally longer if inadequately treated. Relapse is not uncommon.

Complications: Most commonly include osteomyelitis, splenic abscess, genitourinary tract infection, pulmonary disease, and endocarditis. The case-fatality rate of untreated brucellosis is 2% or less with death often resulting from endocarditis caused by Brucella melitensis.

C. Reservoirs

Common reservoirs: Cattle (B. abortus), swine (B. suis), goats (B. melitensis) and sheep.

Less common reservoirs: Bison, elk, coyotes, caribou, and some species of deer may also harbor Brucella species. B. canis is an occasional problem in laboratory dog colonies and kennels; a small percentage of pet dogs and a higher proportion of stray dogs have B. canis antibody titers.

D. Modes of Transmission

Spread through direct contact (of mucosal surfaces and non-intact skin) with secretions of living or dead infected animals, including their tissues, blood, urine, vaginal discharges, aborted fetuses, and especially placentas. It may also be spread through ingestion of raw milk and dairy products (e.g., unpasteurized cheese) from infected animals.

Airborne transmission may occur through inhalation of contaminated aerosols (e.g., in laboratory settings).  

Transmission from strain 19 Brucella animal vaccine or Rev-1 animal vaccine may occur in veterinary practices and associated personnel and farmers.

Person-to-person spread is extremely rare, although it has been reported to occur through bone-marrow transplantation.

E.  Incubation period

The incubation period for brucellosis is highly variable, ranging from 5 - 60 days; illness most commonly occurs about 1-2 months after exposure.

F. Period of Communicability or Infectious Period

Person-to-person transmission of brucellosis is extremely rare. 

G.  Epidemiology

  • Humans are accidental hosts, although there is worldwide distribution of brucellosis.
  • Commonly seen in farmers, ranchers, veterinarians, and other people who work directly with animals. It may also be found in laboratory and slaughterhouse employees, or meat inspectors.
  • Sporadic cases and outbreaks, especially among overseas travelers may occur among consumers of raw (unpasteurized) milk and milk products, especially soft cheeses. Less than 10% of reported cases occur in children under 19 years old. Fewer than 120 cases per year are reported in the United States; incidence worldwide may be largely unrecognized and under reported.

H. Bioterrorism Potential

Category B: Brucella species are considered potential bioterrorism agent. If acquired and properly disseminated, Brucella could cause a serious public health challenge in ability to limit the numbers of casualties and control other repercussions from such an attack.

I.  Additional Information

The Council of State and Territorial Epidemiologists (CSTE) surveillance case definitions for brucellosis can be found at:  https://ndc.services.cdc.gov/conditions/brucellosis/

CSTE case definitions should not affect the investigation or reporting of a case that fulfills the criteria in this chapter. (CSTE case definitions are used by the state health department and the CDC to maintain uniform standards for national reporting.)

Contact the Iowa Department of Agriculture and Land Stewardship (IDALS), (515) 281-8601 (after hours 515-242-0247) with questions about the disease in animals. For information about the risk to  humans, contact CADE at (800) 362-2736. If after hours, instructions will be given to  reach on-call staff.

Fact Sheets and Forms

References

American Academy of Pediatrics. 2000 Red Book: Report of the Committee on Infectious Diseases, 25h Edition. Illinois, Academy of Pediatrics, 2000.

CDC web site. Brucellosis. Available at www.cdc.gov/brucellosis/

Heymann, D.L., ed. Control of Communicable Diseases Manual, 20th Edition. Washington, DC, American Public Health Association, 2015.

Additional Resources

FDA web site providing the latest food recalls:

www.fda.gov/opacom/7alerts.html