Identification of avian strains of Pasteurella multocida in India by conventional and PCR assays

The prevalence of capsular and somatic serotypes were studied among 123 Pasteurella multocida strains isolated from chickens (n = 94), ducks (22), quails (4), turkeys (2) and geese (1) from different geographical regions of India. All strains exhibited similar cultural and morphological characteristics. Ninety-two of the isolates belonged to serotype A:1, the most prevalent serotype, with serotypes A:3, A:1,3, D:3 and F:3 having two isolates each. Only one isolate was positive for serotypes A:4 and D:1. Twenty isolates were untyped. A multiplex capsular PCR assay generated amplicons of sizes 460, 1044, 657 and 854 bp in 106 isolates identified as capsular serotype-A, 15 in serotype D and two in serotype F. Capsular types B and E were not detected in any of the avian isolates studied. The present findings suggest that a multiplex capsular PCR assay may be suitable for the rapid initial identification serotypes P. multocida during epidemiological studies of fowl cholera.     

Morphogenesis of vesiculation in foot-and-mouth disease

The morphogenesis of vesiculation in cattle inoculated (aerosol expsoure) with foot-and-mouth disease virus was investigated by examining alternate, frozen sections of selected tissues stained by fluorescent antibody technique and with hematoxylin and eosin. Viremia preceded the development of lesions, and virus appeared to be transported to the epithelium via papillae. Lesions were initiated usually by the infection of single cells in the stratum spinosum adjacent to the papillae. Three types of lesions were observed. A vesicle developed mainly from the lysis of swollen, spherical cells and the release of intracellular fluid. The 2nd type of lesion was formed mainly by the accumulation of intercellular edema. The 3rd type was characterized by the absence of a vesicle due to seepage and loss of edema fluid and desiccation of the lesion.     

Repair of Bovine and Equine Mandibular Fractures

Clinical findings, surgical repair and postsurgical care of a unilateral fracture of the mandible of a bull and of a bilateral mandibular fracture in a horse are described. Compression plating limited the pain suffered by the animals and resulted in a quick return to function of the mandibles.     

Depressed immunoconglutinin responses in calves experimentally infected with Trypanosoma congolense

Contrary to expectation, immunoconglutinin levels failed to rise significantly in calves infected with Trypanosoma congolense. In addition, it was shown that trypanosome infection appeared to inhibit the immunoconglutinin response to Brucella abortus strain 19. The possible reasons for these findings are discussed.     

Characterisation of Nocardia farcinica isolated from cattle with bovine farcy

Twenty-one strains of Nocardia farcinica isolated from cattle with bovine farcy in the Sudan were examined to determine their taxonomic relationships. The strains had morphological, cultural and physiological properties of Nocardia, but exhibited some variations of minor taxonomic importance. All strains contained lipids characteristic of nocardiae (LCN-As) and all except two were found by immunodiffusion tests to be serologically related to each other, to N asteroides but not to Mycobacterium tuberculosis nor M bovis. Consequently, these organisms were regarded as true members of the genus Nocardia.     

Survival of faecal streptococci in raw and pasteurised egg products

1. The ability of Streptococcus faecalis and Streptococcus faecium strains to survive in egg albumen and liquid whole egg before and after laboratory pasteurisation was studied.

2. Pasteurisation of egg albumen caused a decrease in viable cells of less than 10‐fold, while pasteurisation of whole egg caused decreases of more than 100‐fold in only two of the eight strains studied. After growth in whole egg, some strains were more resistant to pasteurisation in whole egg.

3. Strep, faecalis multiplied in raw and pasteurised whole egg but not in egg albumen.

4. Strep, faecium multiplied in raw and pasteurised whole egg only after an initial decline in viability which was not shown by cells adapted to whole egg. Together with storage temperature this affected the number of viable cells after a storage period of 5 d.

5. In raw and pasteurised egg albumen Strep, faecium strains lost viability; this was maximal at 37 °C and more cells survived as the storage temperature decreased.     

Cardiopulmonary effects of hypercapnia during controlled intermittent positive pressure ventilation in the horse.

The cardiopulmonary effects of eucapnia (arterial CO2 tension [PaCO2] 40.4 +/- 2.9 mm Hg, mean +/- SD), mild hypercapnia (PaCO2, 59.1 +/- 3.5 mm Hg), moderate hypercapnia (PaCO2, 82.6 +/- 4.9 mm Hg), and severe hypercapnia (PaCO2, 110.3 +/- 12.2 mm Hg) were studied in 8 horses during isoflurane anesthesia with volume controlled intermittent positive pressure ventilation (IPPV) and neuromuscular blockade. The sequence of changes in PaCO2 was randomized. Mild hypercapnia produced bradycardia resulting in a significant (P < 0.05) decrease in cardiac index (CI) and oxygen delivery (DO2), while hemoglobin concentration (Hb), the hematocrit (Hct), systolic blood pressure (SBP), mean blood pressure (MBP), systemic vascular resistance (SVR), and venous admixture (QS/QT) increased significantly. Moderate hypercapnia resulted in a significant rise in CI, stroke index (SI), SBP, MBP, mean pulmonary artery pressure (PAP), Hct, Hb, arterial oxygen content (CaO2), mixed venous oxygen content (CvO2), and DO2, with heart rate (HR) staying below eucapnic levels. Severe hypercapnia resulted in a marked rise in HR, CI, SI, SBP, PAP, Hct, Hb, CaO2, CvO2, and DO2. Systemic vascular resistance was significantly decreased, while MBP levels were not different from those during moderate hypercapnia. No cardiac arrhythmias were recorded with any of the ranges of PaCO2. Norepinephrine levels increased progressively with each increase in PaCO2, whereas plasma cortisol levels remained unchanged. It was concluded that hypercapnia in isoflurane-anesthetized horses elicits a biphasic cardiopulmonary response, with mild hypercapnia producing a fall in CI and DO2 despite an increase in MBP, while moderate and severe hypercapnia produce an augmentation of the cardiopulmonary performance and DO2.