Contagious equine metritis: a review

Contagious Equine Metritis (CEM) is a highly contagious venereal disease of horses caused by a fastidious, Gram-negative coccobacillus which grows best on chocolate agar under microaerophilic conditions (5-10% CO2). Clinically, the disease is characterized by a copious watery-to-mucopurulent, vaginal discharge two to ten days after breeding by an infected stallion (11, 13). Shortened estrous cycle lengths are common and may be the only indication of endometritis in some instances (7). Inapparent carriers of the disease in both the mare and stallion make control of the disease more difficult. Outbreaks of CEM have been reported in England, Ireland, France, Australia and the United States. The current information concerning CEM is reviewed.     

Endometrial biopsy findings in mares with contagious equine metritis.

Endometrial biopsy samples before and after treatment were obtained from 10 mares naturally infected and one Pony mare experimentally infected with Contagious Equine Metritis in 1977. The histopathological features were a short-lived polymorphonuclear cell infiltration of the luminal epithelium and stroma followed by a very early and marked mononuclear cell infiltration of the stroma, including many plasma cells. The luminal epithelium responded with cellular proliferation which may have reflected a regenerative response. Following the initial acute response, intercellular basal vacuoles containing amorphous and granular material and degenerate leucocytes, were seen in association with the basement membrane for several weeks following infection and apparent recovery. Specimens taken from 9 mares after treatment suggested a varied response. Endometrial biopsy was useful in demonstrating an endometrial response to infection in individual mares prior to the isolation of the causal organism. Its usefullness as a screening test was limited by the ability of mares to harbour the organism in the lower genital tract whilst showing little or no evidence of acute endometritis.     

Epidemiological observations on contagious equine metritis in Kentucky, 1978.

Contagious equine metritis, introduced by importation of 2 comtaminated stallions from France, affected 54 Thoroughbred brood mares during the 1978 breeding season in Kentucky. The infection was diagnosed bacteriologically and by the use of a complement fixation test. Although lateral spread to stallions, and probably to a few mares, occurred through human agency in the breeding sheds of 2 stud farms, control measures instituted early in the epidemic confined the disease to brood mares bred by stallion on only these farms.     

Responses of pony mares to the agent of contagious equine metritis 1977.

Reproduction of contagious equine metritis 1977 in Pony mares was achieved with cultures of an unclassified Gram-negative coccobacillus. Infected mares developed a vaginal discharge and associated inflammatory changes of the cervix and vagina. There was evidence of variation in pathogenicity between different strains of the organism. Although all infected mares made spontaneous clinical recoveries, the Gram-negative coccobacillus persisted in the genital tracts of a considerable proportion for a variable period after challenge. Recovery of the organism was not associated solely with the occurrence of oestrus. None of the mares has carried over infection into the following breeding season. There was no evidence of localization of the organism in the urinary tract. Cytological examination of smears of cervical and urethral swabs was of diagnostic value only during the clinical phase of the infection. A serological response was demonstrable in all mares that became infected after exposure to the Gram-negative coccobacillus. The complement-fixation test gave more specific and clear-cut results than either the agglutination or the antiglobulin test, with which there was a problem with non-specific reactions. The experimental findings indicate the value of the complement-fixation test for confirming recent cases of contagious equine metritis in the mare.     

An outbreak of contagious equine metritis in 1977 and its effect the following season.

An outbreak of contagious equine metritis occurred in Newmarket in 1977. This survey records the effect on fertility of 20 of the stallions which were infected. Swabbing of mares since then has detected 37 carrier mares harbouring the organism, most frequently in the clitoral area. This swabbing programme reduced the incidence of new cases in 1978 to 3 mares and 1 stallion.     

Contagious equine metritis--outbreak of the disease in Kentucky and laboratory methods for diagnosing the disease.

Contagious Equine Metritis (CEM) was initially reported during the 1977 breeding season in England (Crowhurst, 1977) and Ireland (Timoney, Ward & Kelly, 1977. The disease has also been diagnosed in France and Australia (Huges, Bryden & MacDonald, 1978). The first occurrence of CEM in the United States followed the importation or 2 stallions from France late in 1977 which resulted in an outbreak early in the 1978 breeding season (Swerczek, 1978). Mares usually develop clinical signs of CEM 8--10 days after being covered by an infected stallion, when a copious, greyish discharge is seen. Other mares may not show any outward signs of disease, but may have a shortened dioestrous period. Many mares recover spontaneously from the disease, but a small proportion become carriers of the CEM organism. The stallion does not show any clinical signs of disease, but remains a carrier. In this paper we recommend various laboratory procedures for the diagnosis of CEM in mares and stallions.     

The epidemiology of contagious equine metritis (CEM) in England 1977--1978).

Following an outbreak of CEM in England during 1977 a Code of Practice was introduced to control the disease in 1978. The Code recommended a bacteriological screening programme for Thoroughbred mares and stallions and improved standards of hygiene on the stud farm. As a result of the implementation of the Code a number of asymptomatic carrier mares was detected. Stallions which had transmitted CEM in 2977 and were treated did not transmit the disease during 1978. Two small outbreaks of CEM were reported during the 1978 breeding season.     

Genome sequence of Taylorella equigenitalis MCE9, the causative agent of contagious equine metritis

Taylorella equigenitalis is the causative agent of contagious equine metritis (CEM), a sexually transmitted infection of horses. We herein report the genome sequence of T. equigenitalis strain MCE9, isolated in 2005 from the urethral fossa of a 4-year-old stallion in France.     

Contagious ecthyma in man

The virus of contagious ecthyma of sheep and goats is transmissible to man. The human infection is a relatively benign, self-limited disease. It is frequently encountered in sheep-raising areas among persons handling infected animals or the vaccine. Usually only protective treatment is required, but x-ray therapy will produce prompt regression of the skin lesions.     

Prevalence and abundance of equine strongyles (Nematoda: Strongyloidea) in tropical Australia

A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), Cylicocylus nassatus (67%), Cylicocyclus leptostomus (41%), Cylicocylus insigne (41%), Cylicocyclus radiatus (33%), Cylicocyclus brevicapsulates (22%), and Poteriostomum imperidentum (24%). The remaining cyathostomes were each found in less than 15% of horses. The 4 most common large strongyles were Triodontophorus serratus (30%), Strongylus vulgaris (28%), Strongylus equinus, and Strongylus edentatus (both 22%). The number of species of small strongyles per horse showed a marked variation (mean 10.3, range 2-21) but bore no relationship to either the total number of strongyles per horse, age, sex, and breed of horse, or season. Total number of strongyles per horse (mean 15,890, range 20-165,000) was less than in recent surveys in Europe and the U.S.A. Most horses had low worm burdens, whereas a very small number were heavily infected. Ninety-seven per cent of the total strongyle counts were small strongyles. Strongylus species contributed just over 1%. Small numbers of large strongyles per horse were usual with T. serratus (mean 570), S. vulgaris (mean 330), and S. equinus (mean 330) the most numerous.(ABSTRACT TRUNCATED AT 250 WORDS)