Brucellosis

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Brucellosis

Brucellosis (Undulant fever or Malta fever) is an infectious disease caused by the Brucella bacteria.

Nomenclature

The popular name of the condition is originated due to the inconstance (or undulance) of the fever, which raises and falls constantly. Brucellosis is named after its researcher David Bruce. Maltese doctor and archaeologist Sir Temi Zammit identified unpasteurized milk as the major source of the pathogen in 1905, and it has since become known as Malta Fever, or deni rqiq locally.

In animals this disease is also known as contagious abortion and infectious abortion. In 1897 Danish veterinarian Bernhard Bang isolated Brucella abortus as the agent and the additional name Bang's disease was assigned. In modern usage "Bang's disease" is often corrupted to just "bangs" when ranchers discuss the disease or vaccine.

Transmission and incubation

The disease is transmitted either through contaminated or untreated milk (and its derivates) or through direct contact with infected animals, which may include sheep, pigs, goats, cattle, camels, bison, and other ruminants. This also includes contact with their carcasses.

The incubation period of brucellosis is, usually, of one to three weeks, but some rare instances may take several months to surface.

Symptoms

Brucellosis induces inconstant fevers, sweating, weakness, anorexia, headaches, depression and muscular and bodily pain.

The symptoms are like those associated with many other febrile diseases, but with emphasis on muscular pain and sweating. The duration of the disease can vary from a few weeks to many months or even years.

The disease's sequelae are highly variable and may include granulomatous hepatitis, arthritis, spondylitis, anemia, leukopenia, thrombocytopenia, meningitis, uveitis, optic neuritis and endocarditis.

Treatment and prevention

Antibiotics like tetracyclins, chloramphenicol, rifampicin and the aminoglycosides streptomycin and gentamicin are effective against Brucella bacteria. However, the use of more than one antibiotic is needed for several weeks, due to the fact that the bacteria incubates within cells.

The gold standard treatment for adults is daily intramuscular injections of streptomycin 1g for 14 days and oral doxycycline 100mg twice daily for 45 days (concurrently). Gentamicin 5 mg/kg by intramuscular injection once daily for 7 days is an acceptable substitute when streptomycin is not available or difficult to obtain.

The main way of preventing Brucellosis is by using fastidious hygiene in producing raw milk products, or by pasteurization of all milk that is to be ingested by human beings, either in its pure form or as a derivate, such as cheese.

Brucellosis in dogs

The causative agent of brucellosis in dogs is Brucella canis. It is transmitted to other dogs through breeding and contact with aborted fetuses. Brucellosis can occur in humans that come in contact with infected aborted tissue. The bacteria in dogs normally infect the genitals and lymphatic system, but can also spread to the eye, kidney, and intervertebral disc (causing discospondylitis). Symptoms of brucellosis in dogs include abortion in bitches and scrotal inflammation and orchitis (inflammation of the testicles) in males. Fever is uncommon. Infection of the eye can cause uveitis, and infection of the intervertebral disc can cause pain or weakness. Blood testing of the dogs prior to breeding can prevent the spread of this disease. It is treated with antibiotics as with humans, but it is difficult to cure.

Biological Warfare

The United States biological warfare program focused on three agents of the Brucella group:

- Porcine Brucellosis (Agent US) - Bovine Brucellosis (Agent AB) - Caprina Brucellosis (Agent AM)

US was in advanced development by the end of the Second World War. When the USAF wanted a biological warfare capability, the Chemical Corps offered agent US in the M114 bomblet, based after the 4-pound bursting bomblet developed for anthrax in the Second World War. Though the capability was developed, operational testing indicated that the weapon was less than desirable, and the USAF termed it an interim capability until replaced by a more effective biological weapon. The main draw-backs of the M114 with US was that it was incapacitating (the USAF wanted "killer" agents), the storage stability was too low to allow for storing at forward air bases, and the logisical requirements to neutralize a target was far higher than originally anticipated, requiring unreasonable logistical air support.

Agents US and AB had a median infective dose of 500 org/person, and AM was 300 org/person. The rate-of-action was beleived to be 2 weeks, with a duration of action of several months. The lethality estimate was based on epidemiological information at 1 - 2%. AM was always beleived to be a more virulent disease, and a 3% fatality rate was expected.

References

External links

Prevention about Brucellosis from Center for Disease Control

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