Issue Description 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 or semen. 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
female dogs 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. Other Names Brucellosis, Undulant Fever
Symptoms Brucellosis in humans is usually associated
with the consumption of unpasteurized milk and soft cheeses made from
the milk of infected animals, primarily goats, infected with Brucella
melitensis and with occupational exposure of laboratory workers,
veterinarians and slaughterhouse workers. Some vaccines used in
livestock, most notably B. abortus strain 19, also cause disease in
humans if accidentally injected. Brucellosis induces inconstant
fevers, sweating, weakness, anaemia, 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. In first stage of the
disease, septicaemia occurs and leads to the classic triad of undulant
fevers, sweating (often with characteristic smell, likened to wet hay)
and migratory arthralgia and myalgia. In blood tests, is
characteristic the leukopenia and anaemia, some elevation of AST and
ALT and positivity of classic Bengal Rose and Huddleson reactions.
This complex is, at least in Portugal, known as the Malta fever.
During episodes of Malta fever, melitococcemia (presence of brucellae
in blood) can usually be demonstrated by means of blood culture in
tryptose medium or Albini medium. If untreated, the disease can give
origin to focalizations or become chronic. The focalizations of
brucellosis occur usually in bones and joints and spondylodisciitis of
lumbar spine accompanied by sacroiliitis is very characteristic of
this disease. Orchitis is also frequent in men.
of brucellosis relies on:
1. Demonstration of the agent: blood cultures in tryptose broth, bone
marrow cultures. The growth of brucellae is extremely slow (they can
take until 2 months to grow) and the culture poses a risk to
laboratory personnel due to high infectivity of brucellae.
2. Demonstration of antibodies against the agent either with the
classic Huddleson, Wright and/or Bengal Rose reactions, either with
ELISA or the 2-mercaptoethanol assay for IgM antibodies associated
with chronic disease.
3. Histologic evidence of granulomatous hepatitis (hepatic biopsy)
4. Radiologic alterations in infected vertebrae : the Pedro Pons sign
(preferential erosion of antero-superior corner of lumbar vertebrae)
and marked osteophytosis are suspicious of brucellic spondylitis.
The disease's sequelae are highly variable and may include
granulomatous hepatitis, arthritis, spondylitis, anaemia, leukopenia,
thrombocytopenia, meningitis, uveitis, optic neuritis and
Treatment And Prevention Antibiotics like tetracyclins, 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, because the bacteria incubates within cells.
The gold standard treatment for adults is daily intramuscular
injections of streptomycin 1 g for 14 days and oral doxycycline 100 mg
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.
Another widely used regimen is doxycycline plus rifampin twice daily
for at least 6 weeks. This regimen has the advantage of oral
administration. A triple therapy of doxycycline, together with
rifampin and cotrimoxazole has been used successfully to treat
neurobrucellosis. Doxycycline is able to cross the blood-brain
barrier, but requires the addition of two other drugs to prevent
relapse. Ciprofloxacin and co-trimoxazole therapy is associated with
an unacceptably high rate of relapse. In brucellic endocarditis
surgery is required for an optimal outcome. Even with optimal
antibrucellic therapy relapses still occur in 5-10 percent of patients
with Malta fever. 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.