Amino acid comparison of infectious bursal disease viruses placed in the same or different molecular groups by RT/PCR-RFLP.     

D J Jackwood  S E Sommer  H V Knoblich 《Avian diseases》2001,45(2):330-339

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Gossypol toxicity in preruminant calves     

RZ ZELSKI  JT ROTHWELL†  RE MOORE‡  DJ KENNEDY§ 《Australian veterinary journal》1995,72(10):394-398

SUMMARY Twenty-four of 57 calves fed a diet containing 33% cotton seed meal (CSM) died between 7 and 15 weeks of age. Initial deaths were not accompanied by premonitory signs, but after CSM withdrawal most calves developed rough coats, anorexia, weakness, ascites and subcutaneous oedema. Those that died had large volumes of serous fluid in the body cavities, hard livers of ‘nutmeg’ appearance, and pulmonary congestion. Histopathologically the livers showed periacinar necrosis in acute cases and periacinar fibrosis in chronic cases. Lungs from several calves had oedema, haemosiderosis and fibrosis in some pulmonary vessels. Atrophy of myocardial fibres was present in most cases. The concentration of free gossypol in the diet was 100 to 220 mg/kg. Ante-mortem and post-mortem findings supported a diagnosis of gossypol poisoning. The deaths continued for 4 weeks after withdrawal of CSM from the diet.  相似文献   

Characterization of infectious bursal disease viruses from four layer flocks in the United States   总被引：2，自引：0，他引：2  

Sreedevi B  LeFever LJ  Sommer-Wagner SE  Jackwood DJ 《Avian diseases》2007,51(4):845-850

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Molecular and serologic characterization, pathogenicity, and protection studies with infectious bronchitis virus field isolates from California   总被引：6，自引：0，他引：6  

Jackwood MW  Hilt DA  Williams SM  Woolcock P  Cardona C  O'Connor R 《Avian diseases》2007,51(2):527-533

In this study, we characterized three variant infectious bronchitis virus (IBV) strains isolated in 2003 and 2004 from broiler chickens in California and compared them to previously isolated California variant viruses and to common vaccine serotypes used in the United States. We conducted genetic, serologic, and pathogenicity studies on all three isolates, then tested different vaccines against one of the viruses. Genetically the three variant IBV strains, designated CA557/03, CA706/03, and CA1737/04, were not related to each other. GenBank BLAST database search and phylogenetic analysis of the hypervariable region of the S1 subunit of the spike gene to determine the most closely related viruses to the three variants showed the CA557/03 variant to be 81.8% similar to the CAV/CA56b/91 whereas the CA706/03 and CA1737/04 variant viruses were only distantly related to Dutch/D1466/81 (72.2%), a vaccine strain used in Europe, and Korea/K142/02 (72.7%), a Korean field isolate, respectively. Cross virus-neutralization testing showed that none of the 2003-04 California IBV variant viruses were serologically related to each other or to Ark, Conn, or Mass vaccine strains. In addition the CA1737/04 isolate was also tested against DE072 and found not to be serologically related. All three variant viruses were pathogenic in 1-wk-old broilers and vaccination with Mass/Conn followed by Holland/Conn provided 80% protection against the CA1737/04 virus. The 2003-04 California variant viruses were not compared with variants isolated in California during 1970s and 1980s because, to our knowledge, no genetic information is available and those viruses are no longer obtainable. This study shows that the CA557/03 virus was distantly related to the CAV-type viruses isolated in California in the early 1990s, but that none of the 2003-04 viruses were similar genetically or serologically to the CAL99-type viruses, indicating that new IBV variants continue to emerge and cause disease in commercial chickens in California.  相似文献   

Identification and analysis of the Georgia 98 serotype, a new serotype of infectious bronchitis virus     

Lee CW  Hilt DA  Jackwood MW 《Avian diseases》2001,45(1):164-172

Twenty-five field infectious bronchitis viruses (IBVs) similar to, but genetically distinct from, the DE072 serotype were isolated from several states in the United States from 1990 through 1999 and were examined molecularly and antigenically. A 421-bp sequence in the hypervariable region of the S1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. Cross-virus neutralization testing and entire S1 sequence analysis on selected isolates further confirmed that fact, and we divided the viruses into the DE072 serotype and two other unique groups. In a vaccine protection trial, the commercially available DE072 vaccine showed less than 50% protection against viruses in one of the groups. The majority of the recent isolates belong to that group and share very low antigenic relatedness to the DE072 strain as well as other serotypes of IBV. Consequently, we designated this group as a new serotype, Georgia 98. We developed a restriction fragment length polymorphism analysis that can differentiate this new serotype from all other serotypes of IBV.  相似文献   

Molecular typing of infectious bursal disease virus of Israeli field and vaccine strains by the reverse transcription/polymerase chain reaction/restriction fragment length polymorphism assay     

Meir R  Jackwood DJ  Weisman Y 《Avian diseases》2001,45(1):223-228

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Protection of chickens from infectious bronchitis by in ovo and intramuscular vaccination with a DNA vaccine expressing the S1 glycoprotein   总被引：4，自引：0，他引：4  

Kapczynski DR  Hilt DA  Shapiro D  Sellers HS  Jackwood MW 《Avian diseases》2003,47(2):272-285

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Lack of interaction between avian leukosis virus subgroup J and fowl adenovirus (FAV) in FAV-antibody-positive chickens     

Zavala G  Dufour-Zavala L  Villegas P  El-Attrache J  Hilt DA  Jackwood MW 《Avian diseases》2002,46(4):979-984

Unfounded field speculation has suggested that avian leukosis virus subgroup J (ALV-J) predisposes young meat-type chickens to inclusion body hepatitis caused by fowl adenovirus (FAV). To address this hypothesis, we infected 1-day-old grandparent meat-type chickens carrying maternal antibodies against FAV with a field isolate of FAV associated with inclusion body hepatitis in broilers, ALV-J, or both FAV and ALV-J. We examined the effects of FAV alone or in combination with ALV-J on the basis of clinical signs, overall mortality, growth rate, and gross and microscopic lesions. With such criteria for evaluating possible interactions, we found no significant differences in the dually infected birds in comparison with chickens that received a monovalent challenge with either FAV or ALV-J.  相似文献   

Acute cortisol responses of calves to scoop dehorning using local anaesthesia and/or cautery of the wound   总被引：1，自引：0，他引：1  

SP SYLVESTER  DJ MELLOR  KJ STAFFORD  RA BRUCE  RN WARD 《Australian veterinary journal》1998,76(2):118-122

Objective To measure plasma cortisol responses in calves dehorned using a scoop after administration of local anaesthesia and/or cautery of the wounds.
Design A physiological study with controls.
Procedure There were six treatments: control handling with and without local anaesthesia, dehorning, dehorning after local anaesthesia, dehorning followed by wound cautery, and dehorning after local anaesthesia followed by wound cautery. Blood samples were taken before and after dehorning.
Results Dehorning caused an increase in plasma cortisol concentrations, which decreased a little to plateau values and then declined to pretreatment values 3 to 4 h after dehorning. The peak was smaller after local anaesthesia was administered but when its effects wore off, cortisol concentrations increased and thereafter were similar to those in the dehorned animals. The combination of local anaesthesia and cautery resulted in a plasma cortisol response similar to those in control calves with or without local anaesthesia.
Conclusions If plasma cortisol concentrations reflect the distress being experienced by the calves, then local anaesthesia reduces the acute distress for about 3 h after dehorning but not during the subsequent 3 to 4 h. Combining local anaesthetic and cautery prevented the significant increase in plasma cortisol following dehorning and may eliminate the acute distress caused by scoop dehorning.  相似文献   

The use of biotin-labeled cDNA probes for the detection of infectious bursal disease viruses     

D J Jackwood  F S Kibenge  C C Mercado 《Avian diseases》1990,34(1):129-136

A cDNA library was prepared from the double-stranded RNA genome of the infectious bursal disease virus (IBDV) strain ST-C. The cDNA molecules were annealed into the plasmid pUC9 and used to transform Escherichia coli strain JM107. A cDNA clone that contained IBDV-specific nucleotide sequences was selected and designated STC-1. Radiolabeled probes were prepared from STC-1 and hybridized to genome segment A of ST-C in a northern blot hybridization assay. The STC-1 cDNA was 448 base pairs in length, and its nucleotide sequence indicated that it is located near the VP-2/VP-4 junction in IBDV genome segment A. Biotin-labeled probes were prepared from STC-1 and used in a dot-blot hybridization assay to detect IBDV. Under relatively low stringency conditions of hybridization, the biotinylated probes detected four subtypes of IBDV serotype 1 and a serotype 2 IBDV isolate.  相似文献