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Adenoviral infection was established in imported specialized meat strains of sheep Ile de France and Romni marsh. The disease followed a course typical of chronic interstitial progressive pneumonia with reduced tonus, loss of body weight, and high lethality. The disease was serologically proven by the discovery of specific complement binding antibodies in dynamics against the adenovirus. Titers varied from 1 : 2 to 1 : 32. The infestation was reproduced on sheep and lambs by tracheal infection with ultrafiltrate of changed lung tissue and bronchial lymph nodes. Morphologically the infection manifests itself by considerable hypeplastic processes in the lungs and less pronounced ones in the liver and kidneys. The typical changes indicated are accumulation of lymphoid cells and histocytes in the interstitial tissue, as well as adenomatous expansion of alveolar and bronchial epithelium. Considerable cell polymorphism is observed in the alveoles along with presence of gigantic cells and cell syncytia of desquamous epithelial cells, alveolar macrophages and intranuclear inclusions in some of these cells. Complications of Past. Haemolytica with developing catharalsuppurative pneumonia were observed in some cases.

It was established that the complement binding reaction (CBR) is a suitable and very fast method for horse rhino-pneumonitis diagnostics. Cell cultural virus produced in cell cultures of pig kidneys was used as antigen. The antigen lots tested have no anticomplementary properties. Highest complement binding activity was evident in the non-diluted antigen, which discovered specific antibodies in immune serums. The CBR specificity was tested by the aid of homologous and heterologous serums and antigens. The titers of complement binding antibodies in the serums of 255 horses recovered from the disease varied from 1:10 to 1:320, and in some cases even to 1:640. The blood samples investigated were from studs having rhinopneumonitis proven by clinical observations, by virus neutralizing reaction and by virus isolation. In almost all animals under study neutralizing and complement binding antibodies were established simultaneously.

Two isolates, identified as Chlamydia (neorickettsia) were obtained from the lacrimal secretion of calves with an acute infection on two of a total of four investigated farms with a record of infectious keratoconjunctivitis. In about 70% of the calves that survived there were complement-fixing antibodies against the neorickettsial antigen, the titers ranging from 1:8 to 1:64. Calves that yielded the causative agent were investigated in terms of the antibody dynamics. In the remaining herds no specific antibodies were demonstrated in animals that had survived. One of the isolated strains was used to infect (via the external camera oculi) a rabbit. Acute keratoconjunctivitis followed, and the blood serum of the rabbit was found to contain complement-fixing antibodies of a titer within the 1:8-1:16 range from the 30th day on. A neorickettsial strain was also isolated from the ocular secretion of a dog with serofibrinous keratoconjunctivitis, and this was regarded as a rarely encountered finding.

Investigations were carried out on some farms to establish the presence of Chlamydia organisms in spontaneous cases of polyarthritis in calves. Use was made of various methods--chick embryos, light and electron microscopy, and the complement-fixation test (CFT). As many as 9 C. psittaci strains were isolated from synovial liquid of calves affected with polyarthritis from 6 farms in several districts of the country. The isolated strains were identified morphologically by means of electron and light microscope, and serologically--through demonstrating the presence of a group-specific Chlamydia antigen by CFT with a known positive anti-chlamydial serum. There were in the sera of some calves with polyarthritis chlamydial KC-antibodies. Results spoke of the chlamydial etiology of some polyarthritis diseases in calves in this country, confirming and supplementing previous observations of the authors.

The clinical course, serologic response, and morphologic changes were followed up in month-old lambs infected nasally and via the trachea with Rickettsia burneti at the rate of 10,000 ID50/cm3. Rickettsiae were found in the parenchymal organs, the blood clot, the nasal cavity, the trachea, and the feces of the animals killed on the 7th and 21st day of infection. Complement-fixing antibodies were established in the infected lambs with the use of the complement-fixation test from the 5-6th up to the 160th day (period of testing), the highest value of the titer (1:160) being observed on the 32nd day. Demonstrated were changes in the vessels, and degeneration was found in the liver, kidneys, and other viscera along with proliferative changes in the spleen. Guinea pigs and albino mice were successfully made use of to isolate Rickettsia burneti from the infected parenchymal organs, feces, and others of affected lambs.

Studied was the complement-fixation reaction in the diagnosis of the adenovirus infections in calves. It was found that the test is specific and sensitive. A virus suspension of tissue cultures was used as an antigen, its titer varying from 1:8 up to 1:16. Specific complement-fixing antibodies were detected mainly in survivals at serum dilution of up to 1:64. Specific antibodies were established in undiluted sera too taken from animals of infected herds. In some of the tested sera there were both complement-fixing and precipitating antibodies. In calves treated with a live vaccine against adenoviruses the dynamics of the complement-fixing antibodies was followed up.

It was found that the complement-fixation test is a prompt and suitable method in the diagnosis of the Aujeszky's disease virus, the antigen employed being a cell culture virus. A virulent virus, a slightly virulent one, and the vaccinal mutant strain MK have shown a good complement-fixing activity and they detect specific complement-fixing antibodies in the immune serum. By means of cross CFT an antigenic relation has been established between some strains of the Herpes group and the Aujeszky's disease virus, it being predominantly unilatera. In Aujeszky's disease antisera neutralizing and complement fixing antibodies have been deomonstrated in titres up to 1:64, and in MK antisera--CF-antibodies only. In blood sera from farms with a moderate course in the manifestation of Aujeszky's disease the titre of the CF-antibodies has been 1:8.