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The method of cell agglutination with concanavalin 'A' was employed to study lymphocytes from the peripheral blood of cattle spontaneously infected with the virus of leukosis. The infection in the animals was demonstrated through the agar gel immunodiffusion test based on the presence of antibodies. As controls served lymphocytes of normal cattle that were serologically and clinically negative for leukosis as well as lymphocytes, of cattle that were immunized with the virus of the mucous disease and with adeno-, rota, and parainfluenza-3 viruses. It was found that 10(6) lymphocytes of cattle infected with the leukosis virus was agglutinated by concanavalin 'A' used at the rate of 500-2000 microgram/cm3, while the same amount of lymphocytes of normal animals or animals that were immunized against the other viruses got agglutinated by concanavalin 'A' at 4000-8000 g/cm3.

We studied the hide, neck knots, as well as the liver of calves infected intradermally with strain KOS-Haskovo of Bovid Herpes Virus 2. On the spot of the injection we found necrotic changes in the superficial strata of the epidermis, hydropic distrophy of St. spinosum and also eosinophil intranuclear inclusions in separate epithelial cells. Intranuclear acidophil inclusions were proved also in the macrophages of the lymph knots, whereas in the liver we found a reactive lithic micronecroses. The ontogenic cycle of development took place in the cytoplasm of the infected cell and during this process the nucleocapsid was formed in the nucleus, whereas the virion was formed in the cytoplasm with the membrane elements. It was proved that changes were due to the virus which has a wide range of alteration in the bodies of the calves.

The uterotropic strains SH6 and O1 were studied immunoelectrophoretically to establish their antigenic relationship. The more readily diffusing component of the O-antigenic fraction of the strains proved immunologically identical with LPA of the R Brucella organisms, while the slower component showed common determinants with the O-antigenic fraction of Yersinia pseudotuberculosis. Immunodiffusion revealed that the O-antigenic fraction of the O1 strain and LPA of the S Brucella organisms contained common antigenic determinants having a weak immunologic activity, and this could explain the agglutination reaction after Wright and Huddleson of the sera from cows with infections caused by the uterotropic strains described. It was established through electrophoresis that in contrast to Yersinia enterocolitica 373 the O-antigenic fraction of the uterotropic strains is immunologically identical with LPA of the R Brucellae. An analogy is shown to exist between the immunologic activity of cow sera from infected animals and the A substance as well as at higher agglutination titers after wright of substance B as described by Amarasinghe.

A study was carried out for the presence of chlamydia on 103 farms with records of abortions. Employed were methods of infecting chick embryos via the yolk sac, the complement-fixation test, and electron microscopy. Five chlamydia strains were isolated from aborted fetuses on 5 out of 11 studied farms. Statistical processing of the serologic results obtained revealed that on 20 farms up to 71 per cent of the cows that miscarried were serologically positive for chlamydia, showing titers within the range of 1:8-1:1024 and an average geometrical titer of 34. On other 35 farms these indices were 23.45 per cent, 1:8-1:512, and 28, respectively. On 48 farms serologically negative were 98.94 per cent of the cows that miscarried, while the average geometrical titer was less than 2. Serologic conversion at a replicated serologic investigation was established in 4 out of 5 enzootics of abortions. No chlamydia antibodies were found in sera taken from a total of 4,804 normal cows and heifers from sound farms.

Studied were a total of 220 samples of material taken from the respiratory tract of calves and from fetuses of cows that miscarried for the presence of Haemophilus bacteria. Haemophilus somnus was isolated for the first time in this country from the respiratory tract of calves (10.1 per cent) and from fetuses of cows with abortions (6.2 per cent). Haemophilus somnus was found in calves that had contracted respiratory diseases in 13 per cent of the cases, and in clinically normal calves--in 3.5 per cent of the cases. It was isolated both in pure culture and in mixed culture with P. multocida, M. bovirhinis, M. arginini, V. fetus, and C. pyogenes. As many as 21 strains of Haemophilus somnus were isolated, having the same morphologic, cultural, and biochemical properties characteristic of the species.

The study of 30 strains of Escherichia coli, isolated from calves on various farms of the district of Haskovo, revealed that 70.0% of them manifested resistance to drugs. The capacity of calf E. coli organisms of being donors of resistance factors pointed to the episomal nature of their polyresistance. The comparatively readily effected transmission of drug resistance from E. coli isolated from calves was shown to be potential clinical and epizootic hazard. Such animals proved to be carriers and a source of R+ Escherichia coli organisms. It was found that the transmission of drug resistance was not coupled with the transmission of chromosomal inheritance. A high frequency of the drug-resistance transmission phenomenon was established.

Studied were a total of 119 cows of the Bulgatian Brown breed in different physiologic status at various numbers of days following parturition. Thirty-seven of the animals showed puerperal endometritis, while the remaining showed a normal course during puerperium. Uterine secretion and biopsic material for bacteriologic and histologic investigation were taken from all cows. Sixteen species of organisms were isolated from the animals with endometritis, and 12 species - from those with normal puerperium. Highest bacterial counts in both groups were found on the eighth to twelfth day, however, with the endometritis-affected cows they remained at a comparatively high level up to the 40th day after giving birth. With the cows of normal puerperium the bacterial count was found to drop abruptly after the twelfth day. No correlation was found between the bacterial and the histologic finding. Histologically, recovery processes set in by the 25th-30th day and clinically, the involution of the uterus set in by the 30th-35th day after calving.

The enterotoxemic from of calf colibacteriosis was observed on a total of 18 occasions in newborn animals. Clinically, the disease was manifested with diarrhea, depression of the eyes, fast dehydration, the calves tending to go down and lie for a prolonged periods, with high death rates. Some of the diseased calves showed nervous symptoms. Escherichia coli 0126 was isolated from the intestinal content and the mesenterial lymph of the affected calves. It proved virulent for albino mice. Morphologically, there were strongly expressed circulatory disturbances--hyperemia, perivascular edemas, hemorrhages (Fig. 1 and 2) thrombi (Fig. 3 and 5), with a vacuolar and parenchymal dystrophia of the liver, kidneys, and heart.

Described is the course of a virus diarrhea in calves aged from 40 up to 180 days, the morbidity rate reaching 50 per cent and the mortality rate--28 per cent. The morphologic survey established erosions and inflammatory lesions in the mouth, abomasum, rumen, and intestines. Histologically, there was balooning degeneration of the cells involved as well as karyopycnosis. Virus strains were isolated from the spleen of diseased calves. They were identified as the causative agent of the virus diarrhea-mucosal disease complex. It was found through immunodiffusion that a specific viral antigen exists in the involved mucous membranes of the intestinal tract. The live vaccine was found to be promising of the immunoprophylactic means tested.

Isolated were two types of bacteria (having common morphologic and cultural behaviour and related antigenic composition) from aborted fetuses and placentae of cows with a positive reaction after both Huddleson and placentae of cows with a positive reaction afterboth Huddleson and Wright. They were shown to be new species of the group Mimeae and the genus Yersinia. It was demonstrated through immunodiffusion and immunoelectrophoresis that these new bacteria present antigenic relationship with Brucella organisms. A common O-antigen determinant was found to exist in the isolated bacteria and the S-and R-Brucellae and Br. ovis. The pathogenic effect was tested of the newly isolated bacteria on experimental animals, establishing a certain degree of uterotropism. An abortion was reproduced in a pregnant heifer by means of the intravenous injection of a bacterial culture. The serologic reaction presented by the animal proved comparable with that of cows exhibiting a natural infection process.

Calves, aged 20 days, were experimentally infected with Salmonella dublin. The animals of one-group were treated at the rate of 6.10(8), and those of another--at 2.10(10) up to 4.10(10) live bacterial cells. The calves of the first group showed no clear clinical symptoms of a disease; neither did they manifest regular shedding of bacterial cells. The calves of the second group presented a typical clinical picture, with more regular shedding of bacteria through nasal discharges and the feces. After killing the animals Salmonella dublin organisms were found in all parenchymal organs and in the lymph nodes. Morphologically, the prevalence was established of inflammatory necrobiotic processes in the liver, with activation and proliferation of the sinus endothelium of the lymph nodes, and catarrhal inflammation of varying manifestation in the small intestine.

Described is a respiratory enzootic in calves aged 30 to 90 days. Two cytopathic strains of the bovine respiratory syncytial virus were isolated from diseased calves in a cell culture of lamb thyroid. Clinical observations and the results of virologic and serologic investigations have revealed that mixed infections of the respiratory syncytial virus and the mucosa disease virus take part in the etiology of the respiratory enzootic described.

Bacteriologic investigations of embryos, fetuses, and placentae of cows that had miscarried, uterine and milk samples taken from animals with endometritis and mastitis, and bull semen samples revealed the presence of Corynebacterium pyogenes. It was established that this organism ranks first in the group of occasionally pathogenic microflora that was associated with the occurrence of abortions in cows. It was isolated from in 9.2 per cent of the cases from fetuses, 5.3 per cent of the cases from embryos, and 8.1 per cent of the cases from placentae. On farms with records of Corynebacterium pyogenes abortions all endometritis and mastitis cases could be associated with the same infection. The organisms was demonstrated in the uterine secretion in both clinically normal cows and bull semen. Corynebacterium pyogenes was found to be viable for a long time, and, therefore, represented a serious source of infection--abortions, endometritis, and mastitis.

Studied were a total of 322 samples of water, feed, and grass vegetation with soil from a region where there were records of unspecific tuberculin reactions with cattle. Investigations were also carried out on viscera and lymph nodes of 120 slaughtered cattle. It was found that the atypical acid-fast mycobacteria were widely spread in some regions of Cuba: 42.5% were found in grass samples, 37.5%--in soil samples, 35.0%--in water ones, and 9.6% in feed samples. Atypical mycobacteria were isolated in 35.0% of the cases with internal organs and lymph nodes of slaughtered healthy animals. Established were as many as ten species of such bacteria, prevailing being M. aquae B, M. aquae A, M. smegmatis, and M. phlei. Suggested is the preparation of an allergen from selected strains of atypical mycobacteria to carry out differential tuberculin tests where suspected tuberculin reactions were recorded in the practice.

A virus was isolated from the lymph nodes of a cow. By its cultural, physical, chemical, and biologic properties it proved identical with the standard bovine respiratory syncytial virus. It multiplied well in cell cultures of calf kidney at pH 7--7.5. Introduced in 20-day-old guinea pigs the virus caused anorexia, bristling up of hairs, stunting, and occasionally death. The inoculated guinea pigs developed pneumonia of a proliferative type with Langhans' giant cells. The interrlationship between the isolated virus and the standard oncorna virus, type C, is discussed.

Results are given of studies on the adenoviral infections in cattle in the region of Southeast Bulgaria. Serologic methods were used to elucidate some moments of the enzootic process and the part played by bovine adenoviruses in the etiology of the respiratory diseases of calves. Demonstrated was the participation of adenovirus strains of group II. It was established that the technologic moments influence the course of the adenoviral enzootics. A successful attempt was made to uncode the type picture and the circulation of types 1, 2, 3, and 8 adenoviruses within the cattle herds. The method of direct immunofluorescence was successfully employed in the diagnostics of adenoviral diseases in calves when alive. Demonstrated was also the presence of specific skin supersensitivity in cattle infected with adenoviruses. Data are given on the specificity of the reaction, the quality and standardization of the allergen, the age-associated dynamics of the process, etc.

Studied were swab samples taken from the oral cavity, the nostrils, and the rectum, resp., the cloaca of a total of 2315 calves, pigs, chickens, poulets, and turkey-poults to demonstrate the presence of fungi of the genus Candida. The material was taken from healthy animals and birds as well as from such that had digestive troubles, bronchitis, and bronchopneumontia. Isolated were the species; C. krusei, C. tropicalis, C. parapsilosis, C. albicans, C. pelliculosa, C. gulliermondii, and C. utilis. The various species were differentiated on the basis of their morphologic and cultural characteristics and their biochemical behaviour. It was established that C. albicans only manifested pathogenic properties. It was experimentally demonstrated that the appearance of a Candida infection was facilitated by the simultaneous application of a fungus culture and antibiotics of a broad spectrum. Histopathologic investigations were carried out of experimentally infected and spontaneously affected birds.

Studied were clinically and paraclinically six cattle manifesting an experimental suppurative surgery infection caused by Cornebacterium pyogenes, strain 1056. It was established that the infection assumes the course of septicaemia with metastases in the viscera, causing severe disturbances in the general condition and leading to death in most cases. Found were also anemia, leukopenia, that alternated with leukocytosis presenting nuclear shift to left, changes in the erythrocyte sedimentation rate in terms of more rapid settling out of r. b. c. The urine presented protein and sediment consisting of 8 to 10 or numerous erythrocytes, 5 to 6 or 10 to 15 leukocytes, single to 8-10 kidney epithelium cells. The rumen content became alkaline, and the infusoria count dropped.

Five adenoviral strains, typed as adenovirus type 1, were isolated from aborted cattle foetuses, taken from farms with abortions in cows. The viruses were isolated from kidneys, lungs and livers of the foetuses. They were isolated from the kidney most frequenty (three strains). Intranuclear basophilic inclusions in the alveolar epithelium of the lungs and in the tubular epithelium of the kidneys have been established in the histological investigations of the internal organs of the foetuses. The isolation of adenoviruses from foetuses has been discussed as an infectious process, emerging as a result of a transplacental infection.

Investigated were a total of 30 cattle 6 of which had experimental surgery infection and 24 showed spontaneously developing suppurative infection. The animals were studied in terms of general status, blood picture, quality of urine and synovia, and rumen content. The dynamis was followed up of the development of sepsis and purulent artritis. It was found that in case of suppurative surgical infections in cattle the general status was invariably affected, the severity of the process depending on its localization and developmental phase. Changes were observed also in the eye fundus and in the urinary and the digestive system. There were anemia and leukopenia which alternated with leukocytosis, and transient changes in the values of the erythrocyte sedimentation rate and the blood electrolytes. The SGOT values almost constantly increased, and the hemoculture was not positive in all cases.

A total of five strains of Bacteroides nodosus were isolated from cattle with interdigital dermatitis on a number of farms. With regard to their cultural and morphologic properties and response to carbohydrates these strains did not differ from B. nodosus strains that caused foot rot in sheep. However, their K-antigen was different from the one of the B. nodosus strains isolated from sheep with foot rot as established via the hemagglutination test. No antigenic variations were found with the strains isolated from cattle. The tests with the proteolytic activity of the isolated strains showed that it was considerably lower than the activity of the strains isolated from sheep.

Studied was the occasional role played by the saliva of leukotic cows in the transmission of the infection to test lambs along with the role of colostrum as a factor neutralizing the leukosis virus in experimentally infected lambs. It was found that bovine leukosis could be transmitted by the saliva of affected animals. Colostrum that contained hightiter specific antibodies was found to be effective in neutralizing the leukosis virus in newborn calves provided no subsidiary infection took place.

Rumen content (pH, number of infusoria, quantity of volatile fatty acids and ammonia) was studied in 151 cattle (50 healthy animals, 15 with experimental suppurative infection and 86 with spontaneous suppurative infection). In cases of cattle suppurative infection a statistically significant reduction was observed in the four rumen content indices: pH from 7.61 +/- 0.02 fell to 6.90 +/- 0.06; number of infusoria--from 295 820 +/- 2890 per cm3 fell to 75 867 +/- 1260 per cm3; volatile fatty acids from 919.7 +/- 10.08 mg% diminished to 489.48 +/- 18.91, and ammonia from 27.69 +/- 0.51 mg% was reduced to 12.23 +/- 0.73 mg%. In case of recovery a tendency toward normalizing rumen content was observed.

By applying the direct immunofluorescent method, a study was carried out on the appearance and accumulation of adenoviral antigen in cattle, in infected cellular cultures from the testes of calves and in epithelial cell obtained by smearing with nasal mucosa and conjunctiva of experimentally infected and spontaneously taken ill with adenoviral infection calves. A specific conjugate was obtained by the writers of the present study. In the cultures from calf testes, the earliest viral antigen was proved 36 hours after the infection in the form of a finely granulated nuclear fluorescence with a yellow-green colour. The highest quantity of fluorescent cells was observed after 72 hours. A specific nuclear fluorescence was observed as early as on the sixth day after the infection in the nasal mucosa of experimentally infected calves. An adenoviral antigen was detected on the tenth day in 30% of the cells, and in separate fields of vision the number of fluorescent cells predominated over the negative ones. During the next days the intensity of the nuclear fluorescence diminished, whereas in the cells obtained by smearing on the eighteenth and twenty fourth days of the infection of calves, it was no longer observed. No adenoviral antigen was proved in the first preparations produced from spontaneously ill calves. Such was proved after a second taking of nasal and conjunctival samples six days later. A conclusion was drawn that the immunofluorescent direct method allows the identification of an adenoviral antigen in cells of the epithelium of the upper respiratory routes during the first days of calves infected with adenoviruses.

Through the implementation of the technique of ligated intestinal segments with established the enteropathogenic character of strains E. coli, isolated from calves by means of enteritis. The enteropathogenic E. coli provoked dilatation of the ligated intestinal segments on the basis of the enterotoxin produced by them, whereas in the case of the non-enteropathogenic ones such a reaction was not observed. The dilated intestinal segments were filled with an exudate of watery consistency under pressure and an edema of the mucosis and mesentery was observed. The strain investigated is determined as enteropathogenic or not if it causes dilatation of the ligated intestinal segment in two of the calves tested. Out of the 272 E. coli strains only 43/15.8% proved to be enteropathogenic. The enteropathogenic E. coli refer most frequently to serotypes 08,0101 and 09.

Studied was the occasional role played by vertical transmission of the leukotic infection via the placenta under experimental conditions and in the field. Studies were also carried out to establish the transmission of the infection through the semen as well, using bull semen and test lambs as most susceptible to the virus of bovine leukosis. It was found that at the experimental infection of sheep with the bovine leukosis virus intraplacental infection of part of the fetuses took place. On dairy farms with a widely spread infection (more than 50 per cent) in cattle the newborn calves were found to respond positively immediately after birth and prior to sucking colostrum, having specific leukosis antibodies, though in a low percent. No transmission of leukosis was found with the semen of leujotic bulls.

Studied were a total of 221 strains of Salmonella enteritidis isolated from birds, pigs, cattle, dogs, rodents, forage, environment, food products of animal origin, and human beings, in terms of their phage typing, in order to study the epizootiology of the foci of infection. Twelve phages were established: 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, 15, 19, 20 and 21. Most widely distributed proved phage type 6a, followed by phage type 2a. The remaining phages occured more rarely, and some of them--15, 19, 20 and 21--were found only in particular districts and farms.

The location of the rotaviral precipitating antigen and the possibility for its production from cattle rotaviral strains adapted on cell cultures of calf kidney were investigated. Highest titer antigen was produced by concentration with ammonium sulfate simultaneously from the maintaining medium and from the cell monolayer. Comparative studies on the antigenic and physico-chemical properties of the cell-cultural and the faeces rotaviral precipitating antigen were made. The identity of both antigens was proven by the immunodiffuse reaction and by their resistance to ether and tripsine. A considerably higher temperature sensitivity was established of the cell-cultural precipitating antigen as compared to that from faeces. The precipitating antigen was used for confirming the presence of antirotaviral antibodies in the serums of cattle, man and sheep.

The clinical symptoms and the morphologic picture of calf enterotoxemia are described. Studied were a total of thirty-two dead and slaughtered animals. Bacteriologically, the disease was shown to be caused by types A, D, and C of Clostridium perfringens. Types C and D proved pathogenic for guinea pigs, while type A did not. Isolated was a strain of Clostridium perfringens, which had high toxigenicity. It was found that calves were fairly often affected with the disease. Most severe were the infections caused by type C of Cl. perfringens, with most pronounced morphologic lesions. There were differences in the changes caused by all three types of the organism in calves, which made it possible to distinguish them as causative agents. Type A induced slight icterus and slightly manifested hemosiderosis of the liver, kidneys, and spleen; type D was responsible for severe injury and hyalin dystrophy of the kidneys; and type C caused necrotic enteritis, pronounced hemorrhagic diathesis, degenerative changes in the ganglial cells, and demyelinization of the brain.

It was found that the pathogenic and occasionally pathogenic bacteria were readily transmitted in cows, originating from the genital tract, and more specifically from the uterine and vaginal discharge to the udder through the lactogenic route. The study of a total of 183 metritis-affected cows for the presence of Streptococcus uberis revealed that the pathogen could be found in the genital tract and in the udder in 20.7 per cent of the investigated cows, and it could be isolated simultaneously from the two organs in 82.6 per cent of the cases. In another group of cows also affected with metritis the study for the presence of different bacterial agents established coincidence in their simultaneous isolation from the uters and the udder in 61.2 per cent of the cases.

A total of 24 horses and 42 cattle with a variety of local suppurative processes (wounds, abscesses, phlegmons, tendovaginitis, etc.) were studied under conditions of the clinic with regard to the most commonly found microbial species and the opportunity to work out antibioticogrammes in terms of the effectiveness of 11 of the chemotherapeutic agents widely used in the practice. It was found that prevailing in horses were staphylococci and streptococci. In cattle Corynebacterium pyogenes was predominantly established. Besides, there was a rising trend in the part played by representative agents of the occasionally pathogenic microflora (Ps. aeruginosa, Pr. vulgaris, Escherichia coli) as the causative species of local suppurative processes. These organisms were fairly often isolated in association with other species, while they were more rarely found as the only acting ones in a particular case. Best effects of the antibiotics tested could be expectedly produced by gentamycin (82.5 per cent), carbenimycin (74.2 per cent), oxacyllin (72.7 per cent), ampicillin (68.2 per cent), and canamycin (61.8 per cent). At the same time, the effectiveness produced by some of the antibiotics widely employed in the practice, such as chloramphenicol, tetracycline, streptomycin, and penicillin was below 50 per cent.

Studied were a total of 58 samples, containing intestinal content of calves that had died of enteritis as well as fecal samples and samples from clinically normal calves. Campylobacter spp. were isolated in 8.8 per cent of the cases. The isolated 5 strains was determined as Campylobacter fetus subsp. intestinalis. This is the first communication on the isolation of Campylobacter spp. in this country.

Experiments were carried out to isolate cytopathic strains of bovine rotaviruses. Material from a total of 129 positive fecal samples, taken from calves affected with rotavirus gastroenteritis, was used to infect cell cultures. In the roller culturing of 19 of the positive samples in suspension of the MA-104 cell line in the presence of trypsin two cytopathic strains were isolated. The cell line used was more sensitive than the cells of calf kidney.

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.

Tested was the virulence of 20 strains of Aspergillus fumigatus isolated from cow fetuses. All laboratory mice injected with them died, and the pregnant guinea pigs aborted. It was demonstrated that these strains contain exogenic and endotoxic substances which are extracted effectively with alcohol and ether. The mould cultures showed proteolytic, amylolytic, cellulose, and organic acid activity. The biochemical and pathogenic potential of the strains were of great importance for causing abortion.

A total of 28,159 blood serum samples have been examined for brucellosis, 87--for leptospirosis, 84--for toxoplasmosis, 554--for the presence of rickettsii and neoreckettsii, and 193--for total protein content, albumin, and protein fractions, taken from cows in the course of the years on 40 dairy farms in the district of Rousse. Bacteriologically were examined 349 aborted fetuses, 178 samples of estral secretion, 57 placentae, and 1002 samples of washings and seminal fluid from bulls for vibriosis. Bacteriologic investigations were also carried out on 383 fetuses for salmonellosis, listeriosis, and colibacteriosis, and virologic studies of 398 placentae and parenchymal organs of fetuses. Twenty-eight fetuses were studied parasitologically for toxoplasmosis, and 118 blood smears were examined for hemosporidiosis. It was established that most important in the etiology of the infectious abortions in cows in the district of Rousse were Vibrio organisms. They were found in 36.9 per cent of the studied bovine fetuses and in 24.4 per cent of all materials examined bacteriologically. Only 4 cases were noted of neorickettsii from fetuses and placentae. Serologically, there were 23.6 per cent cases positive for neorickettsiosis, and 12.6 per cent--for Q fever; 56.4 per cent of the investigated sera proved positive for leptospirosis. In 0.8 per cent of the examined fetuses there was Escherichia coli. Abortions in cows were also due to anaplasmosis and francaillelosis; 14.2 per cent of the investigated respective sera were positive for toxoplasmosis. On the days of abortions the amount of total protein was 7.13 mg%, that of albumins--36%, and of globulins--64%. It is considered imperative to elucidate the cause of abortions of infectious nature in cows in connection with the establishing of cattle-breeding complexes.

Several methods were employed to obtain lymphocyte cultures from blood samples taken from normal cattle and from cattle affected with enzootic leukosis. Biologic and virologic experiments revealed that the cultures from diseased cattle contained an oncogenic leukosis virus, while those obtained from healthy animals were exempt from such virus. Electron microscopy was applied to study the morphologic aspects of the bovine leukosis virus with a total of 18 lymphocyte cultures. The viral particles noted were shown to have typical configuration and size of type C oncogenic viruses as described in the literature--possessing a central dense nucleotide and double membranes. Seen were also various stages in the development of the virus. Mature virus particles were likewise observed in a stable cell line FLK (percent of the virus) as well as in ultrathin cross sections of the spleen of leukosis-affected animals.

The virologic investigation of clinical and pathological material from calves affected with a respiratory disease at the age of 30 days to 10 months on 16 infected stock-breeding farms led to the isolation of two virus strains (D-117 and Ch-216) on primary cell cultures of fetal calf kidney from the nasal discharge of two 8-month-old calves. By their cytopathic changes, physico-chemical properties and the presence of a group-specific antigen they were said to belong to the adenovirus family. The results of the cross virus-neutralization test pointed to the assumption that they had to be referred to the bovine adenovirus type 1. Discussed is the problem concerning the participation and the importance of individual types of adenoviruses in the acute respiratory enzootics of grown-up calves.

A total of 29 Pasteurella multocida strains were isolated in cases of atypical fowl cholera with swelling of the wattles as well as from pigs and calves with pneumonia. All strains were used to study the metabolism of 10 amino acids. Glutaminic acid was found to be metabolized by all investigated strains. Arginine was metabolized by Pasteurella organisms isolated from mammals (calves and pigs), and was metabolized by Pasteurellae isolated from birds. By their positive reaction with proline and their negative one with alanine the Pasteurella strains isolated in cases of acute cholera differed from all other Pasteurella organisms. Asparagine was metabolized only by Pasteurellae isolated in cases of atypical fowl cholera, and serine--only by Pasteurellae isolated from pigs.

A total of 32 cows equal in terms of breed, annual milk productivity, feeding and tending regime were examined to determine the clearance of the uterine microflora during the puerperal period and establish the correlation between the conception rate and the bacterial clearance. The studies were carried out on the day of calving and on the 3rd, 6th, 9th, 12th and 15th day after that. It was found that in cows manifesting certain troubles during the puerperal period the bacterial count in the uterine discharges was 75.3% higher as early as the very first day following calving, and regardless of the drop after the ninth day, by the fifteenth day it was 64 per cent higher than in animals showing normal puerperium. In 40.8 per cent of the cows the discharge afterbirth on the day of calving showed no microorganisms. The rise of the microbial count was noted after the first day. It reached its maximum values by the 9 - 10th day after calving, after which it showed a dropping trend. The conception rate of cows with a normal puerperium at first service was 58.1 percent.

Bacteriologic investigations were carried out with a total of 295 cattle of the Holstein-Zebu breed that responded positively to tuberculin. Mycobacterium bovis was isolated from 66 animals, and 12 species of atypical mycobacteria were isolated from 94 animals. Parallel studies were comparatively made of the intradermal reaction test and the bacterial findings. Three groups of calves were infected with various atypical mycobacteria, and their response was followed up with the use of the avian and the bovine type of tuberculin on the 100 th day of infection. It was found that the unspecific tuberculin response of cattle in Cuba were not uncommon, and the best proportion of such reactions were shown to be due to the involvement of atypical mycobacteria. The investigated cattle with a positive response to bovine tuberculin at a single intradermal test were harbouring M. bovis in 66 cases (22.3 per cent), atypical mycobacteria in 94 cases (32.1 per cent), and Actinomyces bovis in 7 cases (2.3 per cent). In 128 of the cases (43.3 per cent) both the morphologic and the bacteriologic findings were negative. The cases with a stronger response at the single intradermal tuberculin test in which the skin fold enlarged over 6.5 mm corresponded to a larger extent to the actual specific infection in the animals than to an infection caused by atypical mycobacteria, however, this could not be absolutely stated for all animals. Following a muscular as well as an oral infection of calves with atypical mycobacteria the allergic response was enhanced from the 40 th up to the 100 th day, the positive reaction to avian tuberculin becoming stronger than to bovine tuberculin.(ABSTRACT TRUNCATED AT 250 WORDS)

Somatic antigens were used for the serotyping of a total of 80 Pasteurella multocida strains isolated from birds with acute and chronic form of cholera as well as from mammals with bronchopneumonia. The investigations made use of the agglutination reaction between factorial sera (0:1, 0:2, 0:3, 0:5, 0:6, 0:8, 0:9, and 0:11) and antigens treated with 1 n HCl. The O-factorial sera behaved specifically after absorption with the respective reference antigens. They showed titers of 1:640 or higher than these with homologous antigens through cross-agglutination reaction. Sixty-nine strains (86.25 per cent) were typed, and 61 per cent of those isolated from birds were shown to belong to groups 0:5 and 0:9, while as many as 62 per cent of the strains isolated from pigs were referred to groups 0:1 and 0:2, and 62 per cent of those isolated from calves--to groups 0:2 and 0:9.

A total of 19 fetuses and 10 placentas were studied. Four fetuses and one placenta harboured neorickettsiae, and the remaining fetuses and placentae originated from cows in the serum of which there were complement-fixing antibodies. These ranged within 1:8-1:64. The gross lesions of the fetuses consisted in the presence of edema with enlargement of the liver. The changes were more characteristic histologically. The liver, kidney, heart, adrenals, and occasionally the lung and spleen had foci of histiocytes, lymphoid and plasmatic cells, and fibroblasts, sometimes with the presence of sporadic leukcoytes. The presence of such cell elements agglomerated in foci fairly often built up formations of granulomatous character. The focal processes prevailed, however, there were diffuse reactions too. Histologically, there were in the placenta diffuse edemas, hyperemia, single hemorrhages, and multiple necrotic foci. A correlation was established between the serologic, virologic, and morphologic changes which made more feasible the diagnosis in such abortions.

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.

Studied was spectrophotometrically the nucleotide composition of DNA of Pasteurella multocida strains along with studies on the nucleotide base ratio, the molar relations between nucleotide bases, the guanine/cytosine ratio in percent, and the specificity index adenine-tinin/guanine cytosine. The strains used were isolated from birds with various forms of fowl cholera (acute, atypic, and swelling of the wattles), and from calves with bronchopneumonia. Used were also mutants that were streptomycin dependent, obtained through induction with nitrosoguanidine. Close values were established of the nucleotide bases both with the individual groups of Pasteurella strains and with the mutants and their initial strains. The molar relations showed values around a unit, the guanine/cytosine ratio in percent varied from 40.14 to 43,54 and the specificity index varied from 1.25 to 1.49. Data showed that all studied strains and mutants belonged to one species - Pasteurella multocida, on the one hand, and their grouping could not be made on the basis of their nucleotide composition, on the other - contrary to some other indexes, such as biochemical activity, virulence, and behaviour to specific phages.

A study was carried out on the drug resistance as associated with the virulence of Staphylococcus aureus strains isolated from cows with endometritis. Hirota's method was employed to ascertain that resistance to penicillin, erythromycin, neomycin, and kanamycin was governed by plasmids. It was found at the same time that, fairly often, with the elimination of some of the resistant markers the virulence of the strain variants also dropped. However, these two properties did not correlate with each other.