Pathobiological Studies On Bovine Ephemeral Fever Infected Cattle In District Swabi
Material type: Book ; Literary form:
Publisher: 2015 Dissertation note: Among the non-contagious diseases Bovine ephemeral fever is important disease of cattle the course of the disease is usually three days due to which it is called “three days sickness”. This is transfer to other cattle through insects Culicoides (biting midges a group that include many kinds of flies) and mosquitoes. Bovine ephemeral fever virus (BEFV) has been collected from Culicoides coarctatus, Culicoides brevitarsis, and Anopheles bancroftii (Walker et al. 2012). Cattle and buffaloes are the main species affected from Bovine ephemeral fever (BEF) which gives huge economic losses to the dairy sector. The etiologic agent, Bovine ephemeral fever virus belong to Rhabdoviridae family, enveloped (negative sense) ssRNA virus. It generally recur in Australia, Asia, and Africa also in the Middle East (Walker 2005).
The theme of the present study was detection of BEF virus through Reverse Transcriptase-Polymerase Chain Reaction from the cattle suspected for bovine ephemeral fever virus on the basis of clinical signs. Hematological profile and serum calcium level were checked in the confirmed positive samples for BEFV.
A total of 50 blood samples were collected from the suspected animals in aseptic condition using a sterilized disposable syringe and were preserved in vacutainers (Anticoagulant added n = 50, without anticoagulant n = 50). The 10 blood samples were collected from healthy animals in vacutainers (Anticoagulant added n = 10, without anticoagulant n = 10).
Buffy coat were separated from blood samples and from this the RT-PCR was performed and successfully diagnosed the BEFV infected cattle. Hematology and serum calcium were performed for both confirm positive and healthy animals.
The result showed that BEF virus was diagnosed with the help of RT-PCR in samples suspected for BEFV infection, and there was no virus detected in samples taken from healthy animals. Comparison of hematology between BEFV infected cattle and healthy animals were performed there was no changes in the RBC, Hemoglobin, Hematocrit, MCV, MCH, MCHC, and MID (it include monocyte, eosinophils, and basophils) except Neutrophils, which number was increases and lymphocytes which was decreased in BEFV infection, while in healthy animals there was no change in the whole hematology. Serum calcium was also determined there was decrease in serum calcium level of BEFV infected cattle, while in the healthy animal samples there was no change in the serum calcium level.
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Study On The Pathogenesis Of Co-Infection Of Infectious Bronchitis (Ibv) And Escherichia Coli (E. Coli) In Experimental Chickens
Material type: Book ; Literary form:
Publisher: 2015 Dissertation note: Infectious bronchitis and colibacillosis are infectious diseases affecting chicken of all ages and breeds. They are of major economic importance in commercial chicken flocks, causing huge losses. As both in humans and animals it is well documented that preceding respiratory infection of virus predispose individual to bacterial infection. Moreover, mix infection in poultry which occur when different organisms simultaneously invade birds is a major threat to poultry industry causes highly epidemic debilitating disease with high mortality which eventually leads to economic catastrophe. In recent past prevalence studies of field, E. coli had been reported with high prevalence and exaggerated disease along with other respiratory pathogens, additionally IBV had also isolated from same flocks in same season. Although a plethora of pioneering work had been done on IBV and E. coli in the previous decades but still a window in time exist in revealing there co-infection. Looking to field scenario in our country, the present study was designed to study an ideal challenge model for IBV and E. coli, by reproducing the natural infection.
80 SPF day old broiler birds were arranged into four groups, (A, B, C and D). Each group was comprised of 20 birds. Group D served as uninoculated control while, Group A and B were challenged with IBV on 23rd day of trails, and Group B and C were inoculated with E. coli infection on day 26th. Birds, (n=3) from each group were slaughtered on various days post infection, gross and histopathological lesions were observed and serum samples for HI were taken, throughout experiment. Variable clinical signs were recorded in various groups. In IBV infected group, respiratory distress i.e., tracheal rales, coughing, sneezing and gasping were noted during early stages, later up to 10 days post infection watery diarrhea with ruffled feathers were observed. In mix infected group clinical signs manifested rapidly and were persistent with high severity. Gross lesions in mixed infection were more profound,
including; airsacullitis, tracheitis with catarrhal exudation throughout respiratory tract; severe sepicemic lesions i.e. perihepaitis, pericarditis, pneumonia and polyserositis with swollen and pale kidneys distended by urates. 5 birds died in mix infected group revealed ascites with asphyxiation of trachea with caseous exudate. While in IBV infected group lesions were mild and confined to trachea, airsac and kidneys. Mortality was high in mix infected followed by IBV in which two birds died. While in E. coli and control group mortality were not noted. Histopathological lesions in mix infected group were aggravated markedly tracheal epithelium degeneration, deciliation and sloughing; congestion, interstitial nephritis, leukocytes infiltration, tubular degeneration and necrosis while were observed. In lungs, pneumonia of peribronchiolar area and interstitium with lymphocyte and macrophages infiltration, additionally degeneration and vacuolization of hepatocytes with focal necrotic areas were also noted. In IBV and E. coli group microscopic lesions were of mild degree. GMT of both IBV and mix infected birds were high but were not significant different (P>0.05). Among the groups, statistically significant increase in FCR of birds in mix infected group was observed followed by E. coli, with IBV infected came third in the row. On the bases of these findings we might conclude that mix infection of IBV and E. coli causes severe lesions with high morbidity and mortality.
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