Contagious Agalactia In Sheep Research Articles

Contagious agalactia of sheep and goats studies on live and dead vaccines in lactating sheep

Pregnant ewes were vaccinated 1 week before lambing started with an attenuated M. agalactiae strain, AIK40. After lambing 1 of 8 ewes developed the joint form of contagious agalactia, 1 ewe developed mild mastitis and 4 more excreted the vaccine strain in the milk. Two months after vaccination these ewes resisted challenge by the subcutaneous inoculation of 1000 ID 50 of strain AIK2 which produced severe disease in 9 unvaccinated controls. A vaccine prepared from a concentrated suspension of formalinized mycoplasma cells (strain AIK2) emulsified in oil and Falba, given at the same time as the live vaccine, failed to prevent symptoms of contagious agalactia in 7 out of 8 ewes. The disease was, however, not so severe and recovery was more rapid than in the control ewes. Of 5 ewes, vaccinated with AIK40 during lactation, 1 became a severe clinical case, 2 developed moderate mastitis and 2 remained normal. The 2 healthy vaccinated ewes, challenged by the left teat canal with 10 6 virulent organisms developed mild mastitis of the left side of the udder. There was no evidence of generalization of the infection. Three control ewes infected in the same way became very severe cases of contagious agalactia.

Contagious Agalactia of Sheep and Goats. The Serial Passage in Goats of an Attenuated Strain of Mycoplasma agalactiae AIK40

The attenuated strain of Mycoplasma agalactiae (AIK40) was passed in a series of 8 young goats by subcutaneous inoculation and re-isolation in blood culture. There was no evidence of reversion to virulence or of alteration of cultural characteristics during the experiment.

Contagious Agalactia of Sheep and Goats. A Comparison of 2 Turkish Strains of Mycoplasma agalactiae by Cross Protection Tests in Goats

Young goats vaccinated with an attenuated strain of Mycoplasma agalactiae (AIK40) were protected against challenge with the original virulent strain (AIK2) from Anatolia and also against challenge with a strain from Catalca in Thrace. Animals recovered

Contagious agalactia of sheep and goats preliminary studies on vaccines

Vaccines against contagious agalactia were tested for their ability to protect goats against challenge by subcutaneous inoculation of a strain of M. agalactiae of known infectivity. The results were assessed on clinical signs, and ante and post-mortern isolation of the challenge organism. They were expressed quantitatively by means of a scoring system. Serological response to vaccination was measured by complement fixation and growth inhibition tests. Of a number of vaccines prepared from formalin killed M. agalactiae those containing concentrated suspensions of mycoplasmata cells in oil adjuvants gave the best protection. A vaccine prepared from a cell suspension emulsified in oil and Falba gave better results than aluminium hydroxide vaccines prepared by the method of Popovici and De Simon (1966). Before challenge, most of the goats vaccinated with oil and Falba vaccine became reactors to the CF test, but none reacted to the GI test. None of the dead vaccines prevented infection after challenge, but the resulting disease was in some instances less severe than in unvaccinated control goats. A live vaccine, attenuated by 40 passes on selective agar, gave complete protection against the challenge inoculation. The vaccine strain could be differentiated from the challenge strain by bacteriological methods. Goats inoculated with the live vaccine had a small residual infection with the vaccine strain when killed 3 to 4 months after vaccination and later work has shown that it can produce clinical contagious agalactia in lactating sheep. Before challenge, all the goats inoculated with the live vaccine became reactors to both the CF and GI tests.

The pathogenicity of Mycoplasma organisms isolated from sheep and goats in Turkey

Sheep and goats were inoculated with 6 type N, 5 type A and 2 type C mycoplasma strains. The results indicate that type N strains of mycoplasma are non-pathogenic when inoculated subcutaneously into goats. Type A strains produced the syndrome of contagious agalactia in sheep and goats as it is seen in Turkey, but without the keratitis. The ID50 in goats of a randomly selected strain of this type was 8·6 organisms. Type C strains isolated in Turkey resembled the Razi strain from Iran in their pathogenicity for sheep and goats. The characteristic lesion produced by these strains was a subcutaneous oedema and necrosis at the site of injection.