Direct isolation of the agent of enzootic abortion of ewes (Chlamydia psittaci) in cell cultures

Isolation of Chlamydia psittaci in McCoy cell coverslip cultures from clinical material from field cases of enzootic abortion of ewes proved more sensitive than diagnosis by examination of smears stained by Ziehl-Neelsen. Enzootic abortion could be diagnosed in the absence of fetal membranes by culture of fetal lung or liver tissue.     

Chlamydia psittaci: is tonsillar tissue the portal of entry in ovine enzootic abortion?

Ewes at 70 days of gestation were exposed by various routes to a culture of Chlamydia psittaci. Chlamydial infection of fetal tissues, generally accompanied by abortion, was observed only in four of six ewes inoculated via the tonsillar crypts and in five of seven ewes injected subcutaneously; most of these also developed antibodies to C psittaci. Seroconversion after normal lambing was also observed in most ewes inoculated orally or by stomach tube, despite failure to detect chlamydia in them.     

Isolation of Chlamydia psittaci and Moraxella bovis from infectious keratoconjunctivitis in lambs

Out of 189 lambs in the flock, 25 animals suffered from bilateral or unilateral conjunctivitis, or keratoconjunctivitis. By serological examination (RVK), positive levels of antibodies to the group-specific antigen of Chl. psittaci were found in three out of six lambs examined by laboratory methods. Bacteriological examination of eye smears of six lambs showed in four cases the infection by microorganisms of Moraxella bovis. Smears from the conjunctivas of these lambs were after preparation instilled in the yolk sacs of six to seven days old chicken embryos. One strain of Chlamydia psittaci was isolated from the same material as Moraxella bovis.     

Use of the IDEIA ELISA to detect Chlamydia psittaci (ovis) in material from aborted fetal membranes and milk from ewes affected by ovine enzootic abortion

The IDEIA ELISA was used to detect Chlamydia psittaci (ovis) antigen in ewes' milk to which were added serial dilutions of chlamydiae titrated as inclusion forming units (ifus) in McCoy cell tissue culture. The test was able to detect as few as 35 ifus/ml of the organism. The ELISA was then used to detect chlamydial antigen in fetal membranes and milk from ewes clinically affected with ovine enzootic abortion (OEA). The results were compared with results of isolation of chlamydiae in McCoy cell tissue culture from the same material. The fetal membranes of 17 of 19 ewes were positive for chlamydia when tested with the ELISA but chlamydia could be cultured from only 15 of them. Milk samples from 26 ewes which had aborted between 1 and 34 days previously were tested: chlamydiae could not be cultured from any of them and only one was positive when tested by the ELISA. The results show that the IDEIA ELISA is a sensitive test for the detection of C. psittaci (ovis) antigens. The positive results to this test for the three samples from which chlamydiae could not be cultured suggest that the test is not as specific as culture or that it detected dead organisms. Chlamydiae do not appear to be excreted in the milk of ewes affected with OEA.     

Isolation of Chlamydia psittaci from bull ejaculate

During the repeated serological examination (RVK) in five breeding bulls the positive levels of antibodies to Chlamydia psittaci in titre 1 : 128 were found. In the isolation experiments the pelleted ejaculates deposited in liquid nitrogen were used. The isolation of Chlamydia psittaci on yolk sacs of chicken embryos was positive in two breeding bulls. The isolated strains are labelled GN-33 and OK-107. The serological examination of blood samples was in all five breeding bulls negative on brucellosis (BAB), infectious bovine rhinotracheitis and coxiellosis and positive on PI-3. Bacteriological examination of spermatic fluid proved only sporadic contamination with moulds and saprophytic bacteria.     

Efficacy against ovine enzootic abortion of an experimental vaccine containing purified elementary bodies of Chlamydia psittaci

A vaccine prepared from purified, inactivated elementary bodies of Chlamydia psittaci protected sheep against abortion after subcutaneous challenge with live chlamydiae. Immunoblot analysis of serum samples revealed a consistently dominant antibody response against the chlamydial major outer membrane protein in all vaccinated sheep. Reactions to other chlamydial antigens were also detected but were less pronounced or inconsistent. Serological responses detected by complement fixation were variable and did not correlate with immunity.     

Isolation of Chlamydia psittaci from an aborted bovine fetus

One strain of Chl. psittaci was isolated from two aborted foetuses of two cows coming from the same locality. Tissue from the lungs of the aborted foetuses was used for the isolation tests; after sample preparation this tissue was inoculated into the yolk sacs of chick embryos. It was found on the basis of serological examination (RVK) that both aborting cows had positive levels of antibodies against the Chl. psittaci antigen at a serum dilution ratio of 1 : 64. The serological examination for brucellosis (BAB) and coxiellosis was negative. The bacteriological examination (aerobic and anaerobic cultivation, salmonellae, mycoplasms and moulds) also gave negative results.     

Selenium and vitamin E effect on antibody production of sheep vaccinated against enzootic abortion (Chlamydia psittaci)

The effect of selenium (Se) and vitamin E (vit E) on antibody production of sheep vaccinated against Chlamydia psittaci (ovis) was investigated. Thirty-two sheep, one year old, seronegative to Chlamydia infection, vaccinated against enterotoxemia and dewormed were used. Injectable sodium selenite (0.1 mg/kg b.w.) was given twice to animals of the first group (gSe), with a three week interval. The sheep of the second group (gE) received 1 g vit E each orally, six times at weekly intervals. The animals of the third group (gSeE) were given Se and vit E in doses and routes of administration as in gSe and gE. The animals of the fourth group served as controls (gC) and injected normal saline. The first vaccination was made at the time that the second Se injection was given. Revaccination was made two weeks later. The experiment lasted 29 weeks. The results indicated that Se alone led to a significant increase of Chlamydia antibody response (P < 0.05), but not when it was given in combination with vit E. Animals that received vit E (gE) had much lower titres, just above of those of the controls.     

Isolation and identification of Chlamydia psittaci from pet birds

Culturing of Chlamydia psittaci from pet birds requires the inoculation of a susceptible living host system with suspensions of various tissues from dead birds or with tracheal and/or cloacal swabs and fresh feces from live birds. Cell cultures have been used as the host system. The most commonly used cell cultures for isolation of C psittaci from pet birds are McCoy and mouse L cells. The sensitivity and specificity of cell culture equals or surpasses embryonating chicken eggs and mice, and results can be obtained in less than 7 days. To obtain satisfactory results, the inoculum must be centrifuged onto the cell cultures at 37 C, and the cells must be treated with a metabolic inhibitor such as colchicine or cycloheximide. Chlamydia psitaci can be detected in infected cells by use of fluorescent antibody, Giemsa, or Gimenez staining.     

Isolation and identification of Clamydia psittaci as the pathogen in enzootic abortion of sheep in eastern Slovakia]

Abortions in ewes occurred on a large scale in three localities in eastern Slovakia. Antibodies to the group-type ornithosis antigen were detected in titres of 1 : 128 to 1 : 2048 in the aborting ewes in the mentioned localities. Suspensions were prepared from the four samples of material, obtained either from the placentae and afterbirths of the aborting ewes or from the tissues of the aborted foetuses. Seven-day old yolk sacs of chicken embryos were infected with these suspensions. Four strains of Chlamydia psittaci were isolated and designated EPO-A2-uterus, EPO-B1 aborted foetus-lung, EPO-B2-aborted foetus-lung, EPO-B3-aborted foetus-spleen. Differential diagnosis eliminated some bacteria, toxoplasma, and parainfluenza-3 virus as possible agents responsible for the abortions.     

Evaluation of the impact and control of enzootic abortion of ewes

Despite the availability of effective management and treatment strategies, Chlamydia abortus remains the single most frequently diagnosed cause of infectious ovine abortion (enzootic abortion of ewes, EAE) in the UK and one of the most significant causes of lamb mortality world-wide. In 2007, a survey of UK farmers, veterinarians and other farm animal holders was conducted to gather information on their perceptions of the risk of acquiring infection and the management practices employed to control the disease. The survey indicated that the preferred options for controlling EAE are either through vaccination and/or keeping flocks closed. However, further analysis of data indicates that implementation of these strategies does not provide a guarantee of exclusion of disease from flocks and thus further work is required to improve on current intervention strategies.     

Isolation of Chlamydia psittaci from cases of conjunctivitis in a colony of cats

This report describes the isolation in cell cultures of Chlamydia psittaci from cases of conjunctivitis in a colony of cats. The organism was identified in McCoy cell monolayers by staining the intracytoplasmic chlamydial inclusions with a fluorescent antibody technique, and serological evidence of chlamydial infection in cats was obtained by indirect immunofluorescence. The possible role of C psittaci as an ocular, upper respiratory and reproductive tract pathogen in cats is discussed.