Warning notice near Spring Hill, Grendon Underwood - geograph

''Chlamydia abortus'' is a species in

Chlamydiota The Chlamydiota (synonym Chlamydiae) are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of th ...

that causes abortion and fetal death in mammals, including humans. ''Chlamydia abortus'' was renamed in 1999 as ''

Chlamydophila psittaci ''Chlamydia psittaci'' is a lethal intracellular parasite, intracellular bacterial species that may cause Endemism, endemic Bird, avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include ...

'' along with all Chlamydiota except '' Chlamydia trachomatis''. This was based on a lack of evident

glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...

production and on resistance to the

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

sulfadiazine Sulfadiazine is an antibiotic. Used together with pyrimethamine, a dihydrofolate reductase inhibitor, it is the treatment of choice for toxoplasmosis, which is caused by a protozoan parasite. It is a second-line treatment for otitis media, p ...

. In 1999 ''C. psittaci'' and ''C. abortus'' were recognized as distinct species based on differences of pathogenicity and

DNA–DNA hybridization In genomics, DNA–DNA hybridization is a molecular biology technique that measures the degree of genetic similarity between pools of DNA sequences. It is usually used to determine the genetic distance between two organisms and has been used ext ...

. In 2015, this new name was reverted to Chlamydia.

In humans

There are approximately one or two cases of chlamydiosis diagnosis in pregnant women in the United Kingdom per year. Typically transmission occurs from contact with livestock who have recently given birth. The true prevalence in humans is unknown because serological antibody tests are unable to distinguish between ''C. abortus'' and other more common species such as '' Chlamydia trachomatis''.

In other animals

''Chlamydia abortus'' is endemic among ruminants such as cows and sheep and has been associated with abortion in a horse, a rabbit, guinea pigs, mice, pigs and humans. Infected females shed bacteria near the time of ovulation, so ''C. abortus'' is transmitted orally and sexually among mammals. All ''C. abortus'' strains were isolated or PCR-amplified from the placenta or fetal organs after spontaneous abortion. ''C. abortus'' infection generally remains unapparent until an animal aborts late in gestation or gives birth to a weak or dead fetus. ''Chlamydia abortus'' has been isolated from birds.

Genome structure

''Chlamydia abortus'' has a relatively small genome that contains 1.14 Mbp with 961 protein coding genes.

In humans

In other animals

Genome structure

References

Further reading