Two nonoverlapping clones, pOH405 and pOH632, containing cDNA inserts in the VP2 coding region of genome segment A were selected from a cDNA library prepared from the double-stranded RNA genome of the OH strain of infectious bursal disease virus (IBDV) of serotype 2. Clone pOH405, which is located in the hypervariable segment of VP2, is 328 base pairs long, has nucleotide sequence homology of 72 to 73%, and amino acid sequence homology of 64 to 67% with IBDV strains of serotype 1. Clone pOH632, which is located in the highly conserved C-terminal part of VP2, is 230 base pairs long, has nucleotide sequence homology of 87 to 88%, and amino acid sequence homology of 100% with IBDV serotype 1. The lower detection limit of 32P-labeled probes prepared from both clones was 10 ng of OH-IBDV double-stranded RNA, using high-stringency conditions of hybridization (54 C, 50% formamide) and washing (55 C, 0.015M NaCl, 0.0015M trisodium citrate, pH 7.0, with 0.1% sodium dodecyl sulfate), and autoradiography for 24 hours. Under these conditions, the dot-blot hybridization assay for detection of serotype 2 IBDV double-stranded RNA was 1,000 times more sensitive, using probe pOH632, but only 10 times more sensitive, using probe pOH405, compared with the assay for IBDV serotype 1, using the same probes. Thus, probe pOH632 could differentiate between the 2 IBDV serotypes by nucleic acid hybridization.

Field infectious bursal disease viruses 9IBDVs) were isolated from IBDV-suspected commercial chickens. The variable region in VP2 gene of six Korean IBDV isolates (K-IBDVs) and IBD vaccines was examined using the reverse transcriptase/polymerase chain reaction-restriction fragment length polymorphism (RT/PCR-RFLP) assay. With all K-IBDVs and vaccine IBDVs, a 474-bp fragment of the VP2 gene was amplified and tested with various restriction enzymes. Resseriction enzymes BstNI and StyI differentiated K-IBDV isolates and IBD vaccines into four groups. Reseriction enzyme profiles of K-IBDV isolates were different from them of IBD vaccines. K-IBDV isolates except for 310 isolate had specific SspI and TaqI recognition sites, which were recognized in highly virulent IBDVs, but IBD vaccines had no those sites. This study showed that RT/PCR-RFLP assay was thought to be valuable tool for differentiation of IBDVs and identification of highly virulent IBDV.

Influence of inorganic and organic salts of lithium on activity of amplifiers and concentration of metabolites in plasma of chicken blood in the process of vaccination against infectious bursal disease was studied in the conditions of the Republic of Belarus. After administration of lithium of citrate, sulfate and succinate there were noted the metabolic disorders. Research results testified that a dry live-viral vaccine on the basis of a strain KMIEhV-61 did not render essential influence on biochemical indicators of blood plasma. At the same time, immunization of chickens against application of salts of lithium (carbonate, sulphate, citrate, succinate) caused to authentic decrease in activity of alanine aminotransferase that testified to function oppression of hepatocytes. Application of lithium of citrate, sulfate and succinate made it possible to considerably increase the concentration of uric acid that was connected, apparently, with infringement of secretory function of kidneys. Metabolic disorders were observed in various terms of research - at 3, 7 and 14 days after vaccine administration. | Изучено влияние неорганических и органических солей лития на активность индикаторных ферментов и концентрацию метаболитов в плазме крови цыплят при вакцинации против инфекционной бурсальной болезни (ИББ). Выявлены метаболические нарушения при использовании лития цитрата, сульфата и сукцината. Полученные результаты исследований свидетельствуют о том, что сухая живая вирус-вакцина из штамма КМИЭВ-61 не оказывает существенного влияния на биохимические показатели плазмы крови. В то же время иммунизация цыплят на фоне применения солей лития (карбонат, сульфат, цитрат, сукцинат) приводит к достоверному снижению активности АлТ, что свидетельствует об угнетении функции гепатоцитов. Применение лития цитрата, сульфата и сукцината способствует также достоверному повышению концентрации мочевой кислоты, что связано, по-видимому, с нарушением выделительной функции почек. Метаболические нарушения наблюдаются в различные сроки исследований - на 3, 7 и 14 дни после введения вакцины.

In the conditions of the Republic of Belarus there was realized a morphological study of bone marrow aspirates at different terms chicken of immunization against Gumboro disease which made it possible to analyze the state of immune system for the objective evaluation of immunological status. Research results showed that chicken immunization with a national liquid chick embryo viral vaccine produced on the basis of KMIehV-13 strain against Gumboro disease (infectious bursal disease) promoted the development of immunomorphological remodeling of bone marrow. Application of immunostimulants Alveozan and Nukleovit for poultry vaccination caused more expressed changes revealing in statistically reliable increasing of total number of myeloblastic cells in the majority of cases by means of increasing of immature cells, and then mature cells of granulocytic series, as well as quantity of lymphocytes and plasmacytes