No abstract

Mycoplasma gallisepticum (MG) causes chronic non-fatal diseases in the poultry industry with a remarkable decrease in feed consumption, egg production and other production indices. To study the genetic characteristics of MG isolates in commercial and backyard poultry flocks, 21 positive samples from different regions of Iran were analysed in the period 2012–2017. Typical macroscopic and histopathological lesions of the upper respiratory tract and lungs were found, similar to those reported by other researchers. A 298–361 bp part of the mgc2 gene was sequenced and analysed. Based on the phylogenetic analysis, the Iranian MG isolates fell into four distinct subgroups. The nucleotide difference between subgroups 1 and 4 was remarkable (91.6–94.9%). A 22-amino-acid insertion was present in two of the studied MG isolates, not observed in other vaccine and standard MG strains. The Iranian Veterinary Organisation (IVO) should consider the observed diversity of prevalent MG isolates from both commercial and backyard flocks in designing the strategy for controlling MG. More studies are needed to understand modifications in MG antigenicity and pathogenicity because of the observed genetic variations.

Haemosporidian parasites are responsible for anemia, acute tissue degeneration, and depopulation in wild birds. This study aimed to investigate the prevalence of haemosporidians and also morphologic and molecular evaluation of tissue stages of Haemoproteus sp. in common buzzards ( Buteo buteo ). Eleven free-living common buzzards were referred to the Avian Clinic of Veterinary School of Lorestan University with lethargy, weight loss, and ataxia. Gametocytes of Leucocytozoon buteonis were found in blood smears of six (54.5 %) birds, while one had simultaneous infection with blood stages of Haemoproteus and Leucocytozoon. During histopathological examinations, exo-erythrocytic stages of the genus Haemoproteus were seen in the lung and kidney of a dead bird. This study is the first report of exo-erythrocytic infection of Haemoproteus in common buzzards. Molecular assays confirmed the infection of Haemoproteus sp. (lineage BUTBUT15) in tissue samples. Phylogenetic analysis using cytochrome b gene suggested that BUTBUT15 was more closely related to the lineages isolated from the family Falconidae in contrast to the Accipitridae.

Infectious bursal disease (IBD) virus causes a highly contagious immunosuppressive disease in chickens. A total number of 12 pooled bursal samples were collected during 2014-2015 from broiler farms in different regions of Iran. Typical macroscopical and histopathological lesions of the bursa of Fabricius were found similar to reports by other researchers. A 474-bp part of hypervariable region of VP2 (hvVP2) was sequenced and analyzed. Ten isolates had the characteristic amino acid residues of very virulent IBD (vvIBD) viruses and the other two were identified as attenuated (vaccine) strains. The vvIBD isolates had a unique G to S mutation at position 254, compared to other Iranian vvIBD isolates. Two attenuated isolates had the mutation 253Q, not found in D78 strain, creating virulent variant of vaccine strains. Degree of similarity among the studied vvIBD isolates was relatively high (97.6-100%), proposing a common ancestor for them. However, they were partly different from previous Iranian and neighbor countries' isolates (96.2-97.3% similarity to Shiraz isolate and 95.7-96.7% to Iraq and Turkey isolates). In phylogenetic analysis, the studied vvIBD isolates classified as a separate subgroup in the group of isolates from Iran and neighbor countries. More studies on genetic and antigenic characteristics of these isolates as well as probable modifications in their pathogenicity are needed to evaluate the significance of the mentioned differences.

To determine sequence characteristics and phylogenetic relationships of the nonstructural (NS) gene, the NS genes of 9 avian influenza (AI) viruses were sequenced and compared with other Iranian AI H9N2 viruses available in GenBank. The similarity among the earliest Iranian H9N2 isolate (A/chicken/Iran/ZMT-101/1998) and recent (2007-2011) studied isolates was low (94%). Some of the studied viruses revealed substitutions in RNA-binding and effector domains as well as antigenic regions of the NS protein. Recently studied isolates have a high similarity (97.4%-98.7%) with some Pakistani isolates (like A/chicken/Sawabi/NARC-2434/2006) in the NS gene. In the phylogenetic analysis, recently studied isolates composed a cluster separate from other Iranian isolates and were placed in the neighborhood of some Pakistani isolates. Hence, new Iranian H9N2 isolates may originate from Pakistani isolates. The NS protein of the Iranian H9N2 isolates differed from that of the Iranian highly pathogenic H5N1 viruses. The potential risk of the emergence of a pandemic virus because of the reassortment of the internal genes between H9N2 viruses and highly pathogenic AI viruses on one hand and the genetic and amino acid changes of AI viruses affecting their pathogenicity and immunogenicity on the other hand confirm the importance of continued surveillance of AI viruses.