''Brucella abortus'' is a

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

in the family Brucellaceae and is one of the causative agents of

brucellosis Brucellosis is a zoonosis spread primarily via ingestion of raw milk, unpasteurized milk from infected animals. It is also known as undulant fever, Malta fever, and Mediterranean fever. The bacteria causing this disease, ''Brucella'', are small ...

. The rod-shaped pathogen is classified under the domain Bacteria. The prokaryotic ''B. abortus'' is non-spore-forming, non-motile and aerobic.

Transmission

''Brucella abortus'' enters phagocytes that invade human and animal innate defenses which in turn, cause chronic disease in the host. The liver and

spleen The spleen (, from Ancient Greek '' σπλήν'', splḗn) is an organ (biology), organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The spleen plays important roles in reg ...

are the mainly affected areas of the body. Farm workers and veterinarians are the highest risk individuals for acquiring the disease due to their close proximity to the animals. Swine, goats, sheep, and cattle are a few of the reservoirs for the disease. ''B. abortus'' causes abortion and infertility in adult cattle and is a

zoonosis A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When ...

which is present worldwide. Humans are commonly infected after drinking unpasteurized milk from affected animals or, less commonly, when coming into contact with infected tissues and liquids (afterbirth, etc.). The incubation period for the disease can range from 2 weeks to 1 year. Once symptoms begin to show, the host will be sick anywhere from 5 days to 5 months, depending on the severity of illness. A few of the symptoms of brucellosis include: fever, chills, headache, backache, and weight loss. As with any disease, there can be serious complications;

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, o ...

and liver abscess are a couple of complications for brucellosis. Although rare, ''B. abortus'' (and other ''Brucella'' spp.) can be transmitted between humans, usually via sexual transmission. ''B. abortus'' also affects

bison A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised. Of the two surviving species, the American ...

Species

''Brucella'' has twelve different kinds of species, one being ''Brucella abortus''. Some of the other species are known as '' B. melitensis, B. canis, B. suis, B. ovis, B. neotomae, B. ceti,'' and '' B. pinnipediae''. Each species displays an affinity for specific animals or groups of animals. Cattle and other livestock are the major host species for the bacteria ''B. abortus''. It is usually found to colonize in the liver and spleen. There are many different ways ''B. abortus'' can spread from the different animals and even to humans. Human infections can lead to Bang's disease. When cattle have

stillbirth Stillbirth is typically defined as fetus, fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without vital signs, signs of life. A stillbirth can often result in the feeling of guilt (emotio ...

s and are carrying this disease, other animals nearby can get infected if they ingest it or otherwise come into contact with fluids containing the bacteria. It could also be passed by their semen and urine. Ticks are another source of transmission for ''B. abortus''.

Survival

Temperature plays a huge role in the survival of ''B. abortus''. The bacteria can survive for a longer period of time if they are at a cooler temperature. This is why it can transmit through liquids like milk and tap water. ''B. abortus'' can last a lot longer in animals if they are not watched closely and if the cattle are not treated for it. In humans, it can be caught after noticing signs and the correct tests to determine the type of bacteria.

References

{{Authority control Bacteria described in 1901 Hyphomicrobiales Pathogenic bacteria