Genetic and phylogenetic analysis of the ribonucleoprotein complex genes of H9N2 avian influenza viruses isolated from commercial poultry in Iran

The H9N2 subtype of avian influenza viruses [AIVs] has been isolated in multiple avian species in many European, Asian, African and American countries. Since the first outbreak of H9N2 virus in Iran in 1998, this virus has widely circulated throughout the country, resulting in major economic losses in chicken flocks. Several amino acids in the virus ribonucleoprotein [RNP] complex including the nucleoprotein [NP] and polymerase [PB2, PB1 and PA] proteins are associated with host range and virulence. Our aim was to understand the molecular characterization of RNP complex proteins of Iranian H9N2 subtype isolates. The full length nucleotide sequences of RNP complex genes of two strains designated as Ck/IR/ZMT-101/98 and Ck/IR/EBGV- 88/10 were amplified and sequenced. The phylogenetic analysis revealed that both strains were located in different sub-lineages. However, based on the genetic similarities, PB1, PA and NP genes of Ck/IR/EBGV-88/10 strain had a close relationship with a H7N3 subtype strain, isolated from Pakistan. Most positions of RNP proteins contained amino acids typical of avian determinants of host range. The results showed that the Iranian RNP complex genes have undergone genetic reassortment. Continuous AIV monitoring in poultry industry would help to obtain more information about genetic variation of H9N2 viruses and possible emergence of virulent and/or pandemic viruses

Molecular characterization of non-structural gene of H9N2 subtype of avian influenza viruses isolated from broiler chickens in Iran

The H9N2 subtype of avian influenza viruses [AIVs] have spread in Asia and Middle East countries and have become a serious threat to poultry industry in Iran. Characterization of genes of H9N2 subtype involving in pathogenicity and diagnosis are crucial in control of avian influenza outbreaks. The Nonstructural [NS] gene and its protein products [NS1 and NS2] are important as diagnostic marker, life cycle and pathogenicity of AIVs. The NS gene of five strains, isolated from 1998 to 2010, were completely sequenced and analyzed. All of the examined strains were composed of 890 nucleotides with 230 amino acids. In this regard, only two Iranian strains from GeneBank had 217 amino acids in NS 1 protein. All Iranian H9N2 strains subdivided into two distinct sublineages including I and II. Comparative analysis of NS genes of Iranian strains showed that since 2003, they might have originated from Pakistan H7N3 strains; whereas from 2008 they could be originated from Pakistan H9N2 strains. Although the low pathogenic H9N2 subtype has been permanently circulating from 1998 to the present in Iran, phylogenetic analysis of NS genes revealed that sublineage II has circulated more in poultry industry of Iran. These epidemio-logically variations could be related to vaccination pressure due to massive vaccination or NS gene reassortment in rural and backyard chickens

[Effect of Echinacea purpurea dried extract effect on producing antibody from newcastle disease vaccine in broilers by HI test]

Newcastle disease is one of the most important causes of economic losses in the poultry production and can he resulted in high mortality. Antibody detection is also an important tool for assessment of the immunity against the disease. In the present study a trial was conducted to evaluate the effect of an immune stimulator[Echinacea purpurea] on antibody production against Newcastle disease vaccine. 450 one day old broiler chicks were divide into five groups of three repeat each. For three weeks from day one various doses of Echinacea purpurea extract was prescribed to four treatment groups and to the fifth group placebo in water was prescribed. All groups were vaccinated on days:11, 19, 38. Subsequently. serum samples were collected at days 10. 25, 34.52 of post vaccination from 21 chicks of each group [4 samples of each repeat] and were tested for Newcastle antibody titers by HI test. This experiment showed that the use of Echinacea purpurea extract with the rate of 29, 75Mg per kilo body weight per day had better effects on antibody titers and significantly increased between control group arid treatment groups [p<0.01]. It is also revealed that the use of Echinacea purpurea induces FCR improvement and mortality rate was decreased significantly [p<0.01]

Molecular diagnosis of Marek's disease virus [MDV] in Iran

The purpose of this study was diagnosis of Marek's disease virus as one of the causative agents for visceral tumors in chickens using Polymerase Chain Reaction. Forty blood samples from the chickens without any clinical signs of Marek's disease and another 42 tumoral tissues from commercial chickens were collected. The whole DNA of the samples were extracted using a silica gel DNA extraction kit, then PCR test was performed using specific primers detecting 132bp tandem repeat and antigen A gene of MDV, finally electrophoresis of PCR products was done in Iko[3]/41 agarose gel. No positive results were obtained in blood samples for MDV and it's vaccinal strain, but about 47.6% of samples were positive. The tumoral tissues including liver, spleen, proventriculus, ovary, breast muscle and bursa of Fabricius. The vaccinal strain of MDV [Rispens] was not detected in any of examined blood samples, as the period of viremia for this virus is very short. Serotype 1 of Marek's disease virus was detected as a causative agent of tumors in the chicken farms of Iran as a first step in this study

[Effect of administration of anti-coccidial drugs and vaccines on broiler chicks performance in experimental coccidiosis]

To compare the effect of coccidiostate drugs and coccidial vaccines on the perfrormance of coccidia - infected broiler chicks. Completely randomized design.Nine hundred and sixty day-old Ross 208 broiler chicks. Chicks were randomly assigned to eight treatments. Each treatment contained 3 replicates of 40 chicks. Treatment 1 and 2 [as negeative and positive control] did not receive any coccidiostates or coccidial vaccines. Treatments 3 and 4 fed diets supplemented with Salinomycine and Diclazoril respectively, but did not immunize. Treeatments 5 to 8 immunized with coccidial vaccines [including Livacox Q, Paracox 5, Livacox T, and Iracoc, respectively] by drinking water on 5 days of age. Chicks in treatments 2 to 8 were inoculated with a suspension containing four Eimeria species on 26 days of age. Surveillances for coccidian oocysts of feces samples were carried out from 7 to 13 days of post-challanged. Body weight [BW], body weight gain [BWG], and feed conversion ratio [FCR] were determined weekly. Data for all response variables were subjected to ANOVA. Variable means for treatments showing significant differences in the ANOVA, were compared using the scheffe's test. The results indicated that using coccidial vaccines and coccidiostate drugs decreased oocysts per gram [OPG] of feces significantly [P<0.05]. The highest mean of BW was related to the chicks treated with salinomycine with significant differences in BW among treatments. The lowest FCR was related to non-challanged chicks [negative control].According to the results of this experimental trial, it could be concluded that coccidial vaccines and coccidiostate drugs could decrease the OPG significantly and improve production performance partially, in coccidia-infected broiler chicks