Pathogenesis and Tissue Distribution of Avian Infectious Bronchitis Virus Isolate IRFIBV32 (793/B Serotype) in Experimentally Infected Broiler Chickens

Infectious bronchitis (IB) is one of the most important viral diseases of poultry. The aim of this study was to investigate the distribution of avian infectious bronchitis virus isolate IRFIBV32 (793/B serotype) in experimentally infected chicken. Ninety-one-day-old commercial broilers were divided randomly into two groups (seventy in the experimental and twenty in the control group). Chicks in the experimental group were inoculated intranasally with 105 ELD50/0.1 mL of the virus at three weeks of age. The samples from various tissues were collected at1, 2, 3, 5, 7, 11, 13, 15, and 20 days postinoculation. Chickens exhibited mild respiratory signs and depression. Viral RNA was detected in the kidney, lung and tracheas on days 1 to 13 PI, in the oviduct between, days 3 and 13, in testes between days 1 and 11 PI, and in the caecal tonsil consistently up to day 20 PI. The most remarkable clinical signs and virus detection appeared on day 1 PI. Data indicated that the number of infected chickens and viral RNA detection from tissues was reduced with increasing antibody titer on day 20 PI. The results demonstrated that the IRFIBV32 virus has wide tissue distribution for respiratory, urogenital, and digestive systems

Prirodna mješovita zaraza uzrokovana virusom influence ptica podtipa H9 i virusom zaraznog bronhitisa na farmama tovnih pilića

Although H9N2 AIV (Avian Influenza Virus) is pathotyped as a low pathogenic avian influenza virus, our extensive field experiences over the last decade show serious disease and high mortality in broiler chicken associated with this subtype in many regions of Iran. One of the possible explanations for such high mortality and great economic losses could be mixed infection with other respiratory pathogens such as infectious bronchitis virus (IBV). This investigation was conducted to study the natural co-infections of H9N2 AIV and infectious bronchitis viruses in broiler chicken flocks in Fars province, Iran. Tracheal samples were taken from chickens in 30 closely monitored broiler flocks suffering from respiratory disease with mortality higher than normal range. RT-PCR was performed using primers in order to detect the M protein and the H9 gene of avian influenza A. The multiplex nested RT-PCR was also performed to detect Massachusetts, 793B (4/91) and D274 serotypes of IBV in the samples. In this study, AIV and IBV were detected in 16 (53/3%) and 12 (40%) out of 30 flocks, respectively. The tracheal samples of 11 out of 12 flocks were positive for 4/91 strain of IBV and one for Massachusetts serotype. A mixed infection of AIV (H9 subtype) and IBV (4/91 serotype) was observed in four flocks with severe lesions and 20-30% mortality. The results of this study indicate the high occurrence of natural co-infection of AIV and IBV in Iranian broiler chicken farms showing respiratory signs and they show that the mortality rate in co-infected flocks was significantly higher than others (P<0.05).Premda podtip H9N2 virusa influence ptica (VIP) po patotipu pripada slabo patogenom virusu influence ptica, terenska iskustva posljednjih desetak godina pokazala su da je pojava teške bolesti i velikog pomora tovnih pilića u mnogim dijelovima Irana vezana uz taj podtip. Jedno od mogućih objašnjenja za tako visok pomor i velike gospodarske gubitke mogla bi biti mješovita zaraza s ostalim uzročnicima dišnih bolesti kao što je virus zaraznog bronhitisa (VZB). Ovo istraživanje poduzeto je s ciljem proučavanja prirodne mješovite zaraze virusom influence ptica H9N2 i virusom zaraznog bronhitisa u tovnih pilića u pokrajini Fars u Iranu. Uzorci obriska dušnika bili su uzeti od pilića na 30 promatranih jata tovnih pilića u kojih je bila ustanovljena dišna bolest s pomorom većim od uobičajenog. Rabljen je RT-PCR s početnicama specifičnima za dokazivanje proteina M i gena za hemaglutinin H9 virusa influence ptica A. Višestruka ugniježđena RT-PCR rabljena je za dokaz serotipova Massachusetts, 793B (4/91) i D274 u pretraživanim uzorcima. VIP je bio dokazan u 16 (53/3%), a VZB u 12 (40%) od 30 pretraženih jata. Uzorci dušnika uzeti iz 11 od 12 jata bili su pozitivni za soj 4/91 VZB i jedan za serotip Massachusetts. Mješovita infekcija virusom influence ptica podtipom H9 i virusom zaraznog bronhitisa (serotip 4/91) bila je promatrana na četirima jatima ptica s teškim poremećajima i 20-30%-tnim pomorom. Rezultati ovog istraživanja govore o pojavi prirodne koinfekcije virusom influence ptica i virusom zaraznog bronhitisa u iranskih tovnih pilića koji su pokazivali dišne znakove te da je pomor u jatima s mješovitom zarazom bio značajno veći (P<0,05) nego u ostalim jatima

Prirodna mješovita zaraza uzrokovana virusom influence ptica podtipa H9 i virusom zaraznog bronhitisa na farmama tovnih pilića

Although H9N2 AIV (Avian Influenza Virus) is pathotyped as a low pathogenic avian influenza virus, our extensive field experiences over the last decade show serious disease and high mortality in broiler chicken associated with this subtype in many regions of Iran. One of the possible explanations for such high mortality and great economic losses could be mixed infection with other respiratory pathogens such as infectious bronchitis virus (IBV). This investigation was conducted to study the natural co-infections of H9N2 AIV and infectious bronchitis viruses in broiler chicken flocks in Fars province, Iran. Tracheal samples were taken from chickens in 30 closely monitored broiler flocks suffering from respiratory disease with mortality higher than normal range. RT-PCR was performed using primers in order to detect the M protein and the H9 gene of avian influenza A. The multiplex nested RT-PCR was also performed to detect Massachusetts, 793B (4/91) and D274 serotypes of IBV in the samples. In this study, AIV and IBV were detected in 16 (53/3%) and 12 (40%) out of 30 flocks, respectively. The tracheal samples of 11 out of 12 flocks were positive for 4/91 strain of IBV and one for Massachusetts serotype. A mixed infection of AIV (H9 subtype) and IBV (4/91 serotype) was observed in four flocks with severe lesions and 20-30% mortality. The results of this study indicate the high occurrence of natural co-infection of AIV and IBV in Iranian broiler chicken farms showing respiratory signs and they show that the mortality rate in co-infected flocks was significantly higher than others (P<0.05).Premda podtip H9N2 virusa influence ptica (VIP) po patotipu pripada slabo patogenom virusu influence ptica, terenska iskustva posljednjih desetak godina pokazala su da je pojava teške bolesti i velikog pomora tovnih pilića u mnogim dijelovima Irana vezana uz taj podtip. Jedno od mogućih objašnjenja za tako visok pomor i velike gospodarske gubitke mogla bi biti mješovita zaraza s ostalim uzročnicima dišnih bolesti kao što je virus zaraznog bronhitisa (VZB). Ovo istraživanje poduzeto je s ciljem proučavanja prirodne mješovite zaraze virusom influence ptica H9N2 i virusom zaraznog bronhitisa u tovnih pilića u pokrajini Fars u Iranu. Uzorci obriska dušnika bili su uzeti od pilića na 30 promatranih jata tovnih pilića u kojih je bila ustanovljena dišna bolest s pomorom većim od uobičajenog. Rabljen je RT-PCR s početnicama specifičnima za dokazivanje proteina M i gena za hemaglutinin H9 virusa influence ptica A. Višestruka ugniježđena RT-PCR rabljena je za dokaz serotipova Massachusetts, 793B (4/91) i D274 u pretraživanim uzorcima. VIP je bio dokazan u 16 (53/3%), a VZB u 12 (40%) od 30 pretraženih jata. Uzorci dušnika uzeti iz 11 od 12 jata bili su pozitivni za soj 4/91 VZB i jedan za serotip Massachusetts. Mješovita infekcija virusom influence ptica podtipom H9 i virusom zaraznog bronhitisa (serotip 4/91) bila je promatrana na četirima jatima ptica s teškim poremećajima i 20-30%-tnim pomorom. Rezultati ovog istraživanja govore o pojavi prirodne koinfekcije virusom influence ptica i virusom zaraznog bronhitisa u iranskih tovnih pilića koji su pokazivali dišne znakove te da je pomor u jatima s mješovitom zarazom bio značajno veći (P<0,05) nego u ostalim jatima

Istraživanje gena za otpornost na antibiotik tetraciklin u izolata bakterije Escherichia coli izdvojenih iz tovnih pilića u Iranu.

The tetracycline resistance of E. coli isolates (n = 300) from broiler chickens was investigated in three stages of the rearing period (one-day-old chicks, thirty-day-old chickens and one day before slaughter). Tetracycline resistance genes (tet(A), tet(M), tet(O) and tet(S)) were investigated among 120 tetracycline resistant E. coli isolates. Tetracycline resistance at the three stages of sampling was 67, 90 and 94%, respectively. Of the 120 tetracycline resistant E. coli isolates, 68 (59%) carried the tet(A) resistance gene. The tet(A) resistance gene was present in 32.5% (13/40) of E. coli isolated from one-day-old chicks, 65% (26/40) of E. coli isolated from thirty-day-old chickens and 72.5% (29/40) of E. coli isolated from the chickens on the day before slaughter. None of the tested isolates contained tet(M), tet(O) or tet (S). Tetracycline resistance was relatively high in E. coli isolated from one-day-old chicks, suggesting a high prevalence of tetracycline resistance in the preliminary gut flora of these broiler chicks. Significant increases in the resistance rate of E. coli isolates were found during the 2nd and 3rd rearing period. Tet(A) was the only detected tet resistance gene in these E. coli isolates. The rise of the tet(A) resistance gene during the rearing of broilers is alarming because this plasmid mediated tet gene can be transmitted to other pathogenic and commensal bacteria in the poultry industry.Istražena je otpornost na tetraciklin izolata vrste E. coli (n = 300) izdvojenih iz tovnih pilića triju dobnih skupina (jednodnevnih, 30 dnevnih i pilića jedan dan prije klanja). Ukupno je 120 izolata E. coli otpornih na tetraciklin bilo pretraženo na prisutnost gena za otpornost na tetraciklin (tet(A), tet(M), tet(O) i tet(S)). Otpornost na tetraciklin u izolatima iz jednodnevnih pilića iznosila je 67%, u izolatima iz 30 dnevnih pilića 90%, a u onih izdvojenih iz pilića dan prije klanja 94%. Od 120 izolata otpornih na tetraciklin, 68 (59%) nosilo je gen tet(A). Gen tet(A) dokazan je u 32,5% (13/40) izolata E. coli iz jednodnevnih pilića, u 65% (26/40) iz 30-dnevnih pilića i 72,5% (29/40) iz pilića dan prije klanja. Nijedan od pretraženih izolata nije sadržavao tet(M), tet (O) or tet(S). Otpornost na tetraciklin bila je relativno visoka u izolata iz jednodnevnih pilića, što upućuje na zaključak o visokoj prevalenciji otpornosti primarne crijevne flore na tetraciklin. Značajno povećanje stope otpornosti izolata E. coli ustanovljeno je tijekom 2. i 3. uzgojnog razdoblja. Tet(A) bio je jedini dokazan tet gen u pretraženih izolata. Povećana učestalost gena otpornosti tet(A) tijekom uzgojnog razdoblja tovnih pilića je zabrinjavajuća jer se plazmid prenositelj gena tet može prenijeti na druge patogene i komenzalne bakterije u peradi

Histologic lesions and tissue tropism of H9N2 avian influenza virus in broiler chickens

Background: Avian influenza virus (AIV) subtype (H9N2), not only causes great economic losses in poultry industry of the Middle East countries, but also has some public health significance as well. The aim of this study was to assess the pathological effects of AIV subtype (H9N2) on different organs of broiler chickens and to detect the virus antigen in these organs. Methods: A number of fifty 1-day-old broiler chicks (Ross breed) were randomly divided into two equal (experiment and control) groups and at days 1, 2, 4, 6, 8 and 11 after inoculating virus, antibody titer against H9N2 subtype of AIV was detected in experiment group and tissue samples from trachea, lung, kidney, spleen, thymus, bursa of fabricius, duodenum, pancreas, liver and brain were collected for histopathology and immunofluorescence studies. Results: The antibody titer against H9N2 AIV at days 1, 2, 4, 6, 8 and 11, post-inoculation, in experiment group was 3, 2.4, 1.7, 3.3, 4.2 and 5.6 and in control group, 3, 2.7, 2.34, 1.8, 1.24 and 0, respectively. Histologic lesions in treatment group were observed as follow: lymphoid and reticuloendothelial cell hyperplasia in the spleen and duodenum, lymphoid depletion in the thymus, lymphoid atrophy in bursa of fabricius, lymphocyte infiltration and mild vacuolation of cells in pancreas. Histologic lesions were absent in the liver and brain of inoculated chickens. The H9N2 AIV antigen was detected in the trachea, lung and kidney of inoculated chickens using indirect immunofluorescence technique. Conclusion: H9N2 avian influenza virus is low pathogenic subtype and has epitheliotropic effect in chickens. In intranasal inoculation, it has tissue tropism and pathogenicity for trachea, lung (pneumotropic) and kidney (nephrotropic)

The beneficial effects of spraying of probiotic Bacillus and Lactobacillus bacteria on broiler chickens experimentally infected with avian influenza virus H9N2

ABSTRACT: This study investigated the clinical, antiviral, and immunological effects of spraying Bacillus spp. and Lactobacillus spp. as a single or mixture probiotic compound on experimentally infected broiler chickens with AIV H9N2. Two hundred and forty 1-day-old broilers were randomly assigned to 6 groups as follows: Ctrl− (no challenge AIV; no spray probiotic), Ctrl+ (AIV challenged; no spray probiotic), AI+B (AIV challenged; daily spraying of probiotic Bacillus spp.), AI+L group (AIV challenged; daily spraying of probiotic Lactobacillus spp.), AIV+BL (AIV challenged; daily spraying of probiotic Bacillus spp. and Lactobacillus spp.), and G-DW (daily spraying of normal saline; no AIV challenged). The birds were reared for 35 d. On the 22nd day of age, broiler chickens were challenged by AIV H9N2. The probiotics were sprayed at 9×109 CFU/m2 daily for 35 d. Growth performance, clinical signs, virus shedding, macroscopic and microscopic lesions were evaluated at various days in all groups. Spraying with probiotics improved the body weight gain and food conversion ratio in the AI+B, AI+L, and AI+BL groups compared to the Ctrl+. The severity of clinical signs, gross lesions, pathological lesions and viral shedding in the probiotic treatment groups was lower than in the Ctrl+ group. The findings of this study suggest the daily spraying of Lactobacillus and Bacillus probiotics alone or in combination during the rearing period reduce clinical and nonclinical aspects of H9N2 virus infection; so, it can be effective as a preventive protocol for controlling the severity of AIV H9N2 infection in broilers