Contagious equine metritis (CEM) is a type of metritis (uterine inflammation) in horses that is caused by a

sexually transmitted infection Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are Transmission (medicine), spread by Human sexual activity, sexual activity, especi ...

. It is thus an

equine venereal disease Equine venereal diseases are sexually transmitted infections in horses. They include contagious equine metritis (CEM) (caused by ''Taylorella equigenitalis'') and equine coital exanthema (caused by equine herpesvirus 3). Equine coital exanthema Th ...

of the genital tract of horses, brought on by the ''

Taylorella equigenitalis Introduction and overview ''Taylorella equigenitalis'' is a Gram-negative, non-motile, microaerophilic bacterium of the genus '' Taylorella'', and the causative agent of contagious equine metritis (CEM) in horses. Phylogeny of ''T. equigenital ...

'' bacteria and spread through sexual contact. The disease was first reported in 1977, and has since been reported worldwide.

Signs

Signs in mares appear ten to fourteen days after breeding to an infected or carrier stallion. A gray to creamy vulvar discharge mats the hair of the buttocks and tail, although in many cases, the discharge is absent and the infection is not apparent. Most mares recover spontaneously, although many become carriers. Infected mares are usually infertile during the acute illness. However, the infertility only lasts a few weeks, after which pregnancy is possible. Stallions do not show signs of infection. The first indication of the carrier state is lack of pregnancy in the mares covered by the stallion.

Diagnosis

Diagnosis is made by taking samples for bacterial culture from all accessible sites. In mares, this includes the

endometrium The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional laye ...

cervix The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...

, clitoral fossa and sinuses. In stallions, samples are taken from the skin folds of the

prepuce Prepuce , or as an adjective, preputial , refers to two homologous structures of male and female genitals: *Clitoral hood, skin surrounding and protecting the head of the clitoris *Foreskin, skin surrounding and protecting the head of the penis in ...

urethral fossa A stallion is a male horse that has not been gelded (castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck ...

, urethra, and the

pre-ejaculatory fluid Pre-ejaculate (also known as pre-ejaculatory fluid, pre-seminal fluid or Cowper's fluid, and colloquially as ''pre-cum'') is a clear, colorless, viscous fluid that is emitted from the urethra of the penis during sexual arousal. It is similar in c ...

. Samples are refrigerated and transported to an approved testing laboratory within 48 hours of collection. Blood tests for mares are available for detecting antibodies to ''Taylorella equigenitalis''. Blood tests are not possible for stallions. These tests become positive 10 or more days after infection. If positive, they only indicate that the mare has had the disease in the past, and do not indicate whether the mare is a carrier now.

Treatment

''Taylorella equigenitalis'' is susceptible to most antibiotics, although the carrier state in mares is difficult to eliminate. Most mares with acute endometritis recover spontaneously. Recommended therapy is to infuse the uterus with an antibiotic such as

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

, cleansing the clitoral area with 2% chlorhexidine solution and then applying chlorhexidine or nitrofurazone ointment to the clitoral fossa and sinuses. The entire treatment is repeated daily for five days. It is relatively easy to eliminate the carrier state in stallions using local disinfectant. With the

stallion's penis A stallion is a male horse that has not been gelded ( castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" ...

dropped and the glans extended from the foreskin, the

shaft of the penis A corpus cavernosum penis (singular) (literally "cave-like body" of the penis, plural corpora cavernosa) is one of a pair of sponge-like regions of erectile tissue, which contain most of the blood in the penis during an erection. Such a cor ...

, including the folds of the prepuce and the

, should be cleansed daily for five days with a 2% chlorhexidine solution. After drying, nitrofurazone cream is applied to these areas.

History

The disease was first reported in 1977 on

horse breeding Horse breeding is reproduction in horses, and particularly the human-directed process of selective breeding of animals, particularly purebred horses of a given breed. Planned matings can be used to produce specifically desired characteristics in ...

farms in England, when an unusually high proportion of mares were not becoming pregnant. CEM was also officially confirmed in Ireland and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

in 1977. It was found in United States in 1978 in horses imported to Kentucky from Europe. A second American outbreak occurred a year later in Missouri but in both cases, the diseases were quickly eradicated. In 2008, a

Quarter Horse The American Quarter Horse, or Quarter Horse, is an American breed of horse that excels at sprinting short distances. Its name is derived from its ability to outrun other horse breeds in races of a quarter mile or less; some have been clocked at s ...

stallion standing at stud in Kentucky was found to be carrying ''Taylorella equigenitalis''; an investigation of this case revealed infections in eight other US states, in eleven different breeds of horse.

References

{{reflist

External links

CEM article at Equine-Reproduction.com

* ttp://www.aphis.usda.gov/publications/animal_health/content/printable_version/fs_CEMrev09.pdf Contagious Equine Metritis Horse diseases Theriogenology