Profiling of virulence associated genes of Pasteurella multocida isolated from cattle

Pasteurella multocida is a causative agent of many major diseases of which haemorrhagic septiciemia (HS) in cattle & a buffalo is responsible for significant losses to livestock sector in India and south Asia. The disease outcome is affected by various host- and pathogen-specific determinants. Several bacterial species-specific putative virulence factors including the capsular and virulence associated genes have been proposed to play a key role in this interaction. A total of 23 isolates of P. multocida were obtained from 335 cases of various clinically healthy and diseased cattle. These isolates were examined for capsule synthesis genes (capA, B, D, E and F) and eleven virulence associated genes (tbpA, pfhA, toxA, hgbB, hgbA, nanH, nanB, sodA, sodC, oma87 and ptfA) by PCR. A total of 19 P. multocida isolates belonging to capsular type B and 4 of capsular type A were isolated. All isolates of capsular type B harboured the virulence associated genes: tbpA, pfhA, hgbA, sodC and nanH, coding for transferrin binding protein, filamentous hemagglutinin, haemoglobin binding protein, superoxide dismutase and neuraminidases, respectively; while isolates belonging to capsular type A also carried tbpA, pfhA, hgbA and nanH genes. Only 50 % of capsular type A isolates contained sodC gene while 100 % of capsular type B isolates had sodC gene. The gene nanB and toxA were absent in all the 23 isolates. In capsular type A isolates, either sodA or sodC gene was present & these genes did not occur concurrently. The presence of virulence associated gene ptfA revealed a positive association with the disease outcome in cattle and could therefore be an important epidemiological marker gene for characterizing P. multocida isolates.     

Immune response of chicks to oral vaccination against Newcastle disease and fowl pox

The humoral immune response and immunity conferred in chicks were compared following separate and combined oral vaccination with F strain of Newcastle disease virus (NDV) and HP1 strain of fowl pox virus. The haemagglutination inhibition (HI) antibody titre against NDV and passive haemagglutination (PHA) antibody titre against fowl pox virus were comparable in two respective groups. The serum IgG concentration increased significantly after the second vaccination in all the groups. The NDV vaccine induced significantly higher IgG production as compared to fowl pox virus vaccine. There was no significant difference in serum IgG concentration produced by combined vaccine and separate F strain vaccine. The protection afforded by combined and separate vaccinations did not vary significantly against challenge with virulent strains of NDV and fowl pox virus at different stages.     

An outbreak of gizzard erosion and ulceration in chicks in Zambia

An outbreak of gizzard erosion and ulceration in broilers in Zambia is described. Approximately 100,000 chickens in the age group of 2-9 weeks were affected. Mortality ranged from 5 to 30%. In a majority of cases, crops, oesophaguses and gizzards were engorged with dark brown to black watery material. Lesions were mainly in the gizzard comprising erosions and ulcers. High levels of fish meal in the ration is indicated as a causative factor.     

Sarcocystosis in goats: clinical signs and pathologic and hematologic findings

Clinical sarcocystosis was studied in 37 goats after inoculation with graded doses of sporocysts of Sarcocystis capracanis. Eight uninoculated goats served as controls. Clinical response varied with the dose. Goats inoculated with 10-40 million sporocysts died between 11 and 13 days after inoculation (DAI), from interstitial pneumonia, vasculitis, and necrosis of mesenteric lymph nodes. All goats inoculated with 100,000 or 1 million sporocysts died between 19 and 23 DAI; clinical signs were anorexia, fever (40-41 C), anemia, and weight loss. Four of 4 goats inoculated with 50,000 sporocysts and 1 of 4 inoculated with 10,000 sporocysts died 24, 28, 39, 68, and 61 DAI, respectively. Goats inoculated with 1,000 sporocysts and uninoculated goats remained clinically normal. After day 18 and before day 68, packed cell volume and hemoglobin content decreased to as low as 11% and 3.6 g/dl, respectively. Alanine aminotransferase and lactic dehydrogenase activities were inconsistently increased. Blood urea nitrogen and bilirubin values were increased, reaching as high as 63 mg/dl and 10 mg/dl, respectively. Histologically, thymic atrophy, vasculitis, hepatitis, cholangitis, myocarditis, generalized myositis, and encephalomyelitis were the main microscopic findings. The cause of the anemia in goats that died after day 19 was not determined.     

Subcutaneous pharmacokinetics and dosage regimen of cefotaxime in buffalo calves (Bubalus bubalis)

The pharmacokinetics and dosage regimen of cefotaxime following its single subcutaneous administration (10 mg/kg) were investigated in buffalo calves. Plasma and urine samples were collected over 10 and 24 h post administration, respectively. Cefotaxime in plasma and urine was estimated by microbiological assay technique using E. coli as test organism. The pharmacokinetic profiles fitted one-compartment open model. The peak plasma levels of cefotaxime were 6.48 ± 0.52 µg/ml at 30 min and the drug was detected upto 10 h. The absorption half-life and elimination half-life were 0.173 ± 0.033 h and 1.77 ± 0.02 h, respectively. The apparent volume of distribution and total body clearance were 1.17 ± 0.10 l/kg and 0.45 ± 0.03 l/kg/h, respectively. The urinary excretion of cefotaxime in 24 h, was 5.36 ± 1.19 percent of total administrated dose. A satisfactory subcutaneous dosage regimen for cefotaxime in buffalo calves would be 13 mg/kg repeated at 12 h intervals.     

Non-structural protein 3A for differentiation of foot-and-mouth disease infected and vaccinated animals in Haryana (India)

There are severe international trade restrictions on foot-and-mouth disease (FMD) affected areas. Because of endemic nature of FMD, India started FMD control programme (FMD-CP) using mass vaccination in selected states including Haryana (year 2003). Although no significant incidence of the disease was reported after launching FMD-CP in the state but in order to participate in international trade of animal and animal products, veterinary authorities have to prove that there is no FMD virus (FMDV) circulation in the animal population, for which it is necessary to differentiate the FMD infected and vaccinated animals. For this purpose, an in-house indirect ELISA utilizing baculovirus-expressed FMDV non-structural protein (NSP) 3A was used to find evidence for virus circulation (prevalence of anti-NSP 3A-specific antibodies) by examining serum samples that were collected either before start of FMD-CP or after completion of third phase (Pre-4th) of vaccination in Haryana (India). A significant reduction (P < 0.01) in prevalence of anti-NSP 3A-specific antibodies (possibly carriers) was observed 2 years after launching FMD-CP in Haryana. However, in cattle the percentage of animals with anti-NSP 3A-specific antibodies was found to be significantly higher (P < 0.01) than buffalo, both before (P < 0.01) and after (P < 0.01) launching FMD-CP in the state. The findings of this study suggest that use of FMDV vaccine in cattle and buffaloes in endemic areas reduces virus circulation (carriers) in the vaccinated herds and that the current 3ANSP-ELISA can be successfully used to monitor the FMDV circulation in endemic areas.     

Pharmacokinetics and dosage regimen of cefotaxime in cross-bred calves following single intramuscular administration

The pharmacokinetics, penetration into erythrocytes and plasma protein binding of cefotaxime were investigated in cross-bred calves. Following a single intramuscular dose of cefotaxime (10 mg/kg), the absorption half-life and elimination half-life were 0.13±0.03 h and 2.97±0.72 h, respectively. The apparent volume of distribution and total body clearance were 3.28±0.72 L/kg and 0.78±0.08 L/kg per h, respectively. The extent of penetration into erythrocytes was 24–40% of the total blood concentration. Cefotaxime was bound to plasma proteins of calves to the extent of 25.5–33.6%. A satisfactory intramuscular dosage regimen for cefotaxime in calves would be 11 mg/kg followed by 10 mg/kg at 7 h intervals.Abbreviations ATCC American type cell culture - MIC minimum inhibitory concentration - PCV packed cell volume     

ARTERIOGRAPHIC ANATOMY OF THE ABDOMINAL AORTA IN THE GOAT, DOG, PIG, AND RABBIT

Arteriographic anatomy of the major branches of the abdominal aorta of rabbits, dogs, pigs, and goats was investigated. The origin and location of the celiac, cranial mesenteric, right renal, left renal, caudal mesenteric, and external iliac arteries were demonstrated, and their placement was described in relation to the iliac bifurcation and lumbar vertebral bodies.