Molecular Characterization and Phylogenetic Analysis of Marek's Disease Virus in Iran.

Marek's disease (MD) is a highly contagious, lymphoproliferative poultry disease caused by the oncogenic herpesvirus, serotype 1 Marek's disease virus (MDV-1), or Gallid herpesvirus 2 (GaHV-2). MDV strains have shown a continued evolution of virulence leading to immune failure, and MD cases continue to occur or surge. Meq, the major MDV-1 oncoprotein, induces T-cell neoplastic transformation through several mechanisms including inhibition of apoptosis, cell cycle regulation, and serum-anchorage independent growth. There is no current information on the MDV serotypes and pathotypes circulating in vaccinated commercial farms in Iran, where the birds are vaccinated at the hatchery with GaHV-2 and Meleagrid herpesvirus 1 (MeHV-1) vaccines. This study reports the molecular characterization of a GaHV-2 strain detected in 19 flocks of Iranian layer farms exhibiting MDV-1-like clinical signs and visceral lymphomas. Based on sequencing and phylogenetic analysis of the Meq gene, the Iranian GaHV-2 isolates could be divided into two separate clades regarding molecular features. The clade containing strains was closely related to Italian, Indian, and Hungarian virulent isolates, and the clade was related to American very virulent plus (vv+) isolates. For the first time, the MDV-1 virus was characterized by an outbreak in poultry flocks in Iran. Although MDV-1 strains obtained in Iran's present outbreak are presumably related to virulent (v) and vv+ pathotypes based on nucleotide, amino acid, and phylogenetic analysis of the viruses, they are not confirmed so far. Thus, it is highly recommended to perform further analyses to demonstrate the pathotype characteristics in vivo.

Caracterización molecular y análisis filogenético del virus de la enfermedad de Marek en Irán. La enfermedad de Marek (MD) es una enfermedad altamente contagiosa linfoproliferativa en la avicultura causada por el herpesvirus oncogénico, el virus de la enfermedad de Marek de serotipo 1 (MDV-1) o Gallid herpesvirus 2 (GaHV-2). Las cepas del virus de Marek han mostrado una evolución continua de virulencia que conduce a una falla inmunológica, y los casos de Marek continúan ocurriendo o aumentando. El gene Meq, codifica la principal oncoproteína de MDV-1, induce la transformación neoplásica de células T a través de varios mecanismos que incluyen la inhibición de la apoptosis, la regulación del ciclo celular y el crecimiento independiente del anclaje sérico. No hay información actual sobre los serotipos y patotipos del virus de Marek que circulan en las granjas comerciales vacunadas en Irán, donde las aves se vacunan en la planta de incubación con las vacunas GaHV-2 y Meleagrid herpesvirus 1 (MeHV-1). Este estudio reporta la caracterización molecular de una cepa del Gallid herpesvirus 2 detectada en 19 lotes de granjas de aves de postura iraníes que presentaron signos clínicos sugestivos del serotipo 1 del virus de la enfermedad de Marek y linfomas viscerales. Según la secuenciación y el análisis filogenético del gene Meq, los aislamientos iraníes de GaHV-2 podrían dividirse en dos clados separados con respecto a las características moleculares. El clado que contenía las cepas estaba estrechamente relacionado con los aislados virulentos de Italia, India y de Hungria y el clado estaba relacionado con los aislados americanos muy virulentos plus (vv+). Por primera vez, el serotipo 1 del virus de la enfermedad de Marek se caracterizó por un brote en parvadas avícolas en Irán. Aunque las cepas del virus de Marek, serotipo 1 obtenidas en el brote actual de Irán están presuntamente relacionadas con patotipos virulentos (v) y muy virulentos plus según el análisis de nucleótidos, aminoácidos y filogenético de los virus, hasta el momento no se han confirmado. Por lo tanto, se recomienda realizar más análisis para demostrar las características del patotipo in vivo.

Fowl Adenoviruses D and E Cause Inclusion Body Hepatitis Outbreaks in Broiler and Broiler Breeder Pullet Flocks.

Twenty-four fowl adenoviruses (FAdVs) were isolated from broiler and broiler breeder pullet flocks in Iran during 2013-2016 and were identified and characterized. All FAdVs were from inclusion body hepatitis (IBH) cases, showing an enlarged and pale yellow liver with multiple petechial hemorrhages. Phylogenetic analyses of partial hexon gene sequences are an adequate and quick method for differentiation and genotyping. The isolates were subjected to PCR to amplify a 590-bp fragment from the hexon gene. Sequence analysis revealed the presence of two species D and E. Eighty FAdV isolates were genetically related to the strain EU979378 of FAdV-11 (96.5% to 97.6% identity), and six isolates were related to the strain EU979375 of FAdV-8b (97% identity). The results indicated that two FAdV serotypes (11 and 8b) are high prevalence serotypes of FAdVs in Iran and are pathogenic enough to cause IBH in young chicks. Therefore, preventive measures against FAdV infection on poultry farms should be implemented.

Epidemiology of Avian Infectious Bronchitis Virus Genotypes in Iran (2010-2014).

Infectious bronchitis virus (IBV) in vaccinated chicken flocks continues to cause enormous economic losses to the poultry industry in Iran. A molecular surveillance of IBV genotypes involved in outbreaks of disease was performed. Specimens of trachea, kidney, and cecal tonsil were collected from 250 suspected flocks (more than 2500 samples) and identified between 2010 and 2014. Partial spike glycoprotein gene sequences revealed seven distinct genotypes, including Mass, 793/B, IS720, Variant 2, QX, IR-I, and IR-II, to be circulating in the chicken farms. The majority of flocks (67.6%) experienced infection with an IBV variant unrelated to the vaccine strains. These variants displayed homologies ranging from 54.1% to 78.5% and from 53% to 86% with H120 and 4/91, respectively. These findings reveal the existence of IBV variants genetically different from the vaccine strains currently in use and explain the outbreaks of disease observed in the field. The current work constitutes the first comprehensive survey of IBV in Iran and emphasizes the need for continuous monitoring and rethinking of current preventative measures.

Drug resistance, plasmid profile and random amplified polymorphic DNA analysis of Iranian isolates of Salmonella enteritidis.

The aim of this study was to characterize 49 Salmonella Enteritidis (SE) isolates from different sources (poultry, human, cow, poultry house environment) in Iran with respect to drug resistance, plasmid profile, and random amplified polymorphic DNA (RAPD) analysis. Antimicrobial susceptibility test to 29 agents found 33 resistance patterns among the isolates. No resistance was observed to danofloxacin, levofloxacin, norfloxacin, ceftriaxone, imipenem, and amikacin. The highest resistance (38.8%) was observed to flumequine. Thirty (61.2%) isolates were multidrug-resistant. Six plasmid profiles were detected and a 68-kb plasmid was found in 98% of isolates. Two different primers, MK22 and P1254, were used for RAPD analysis which each produced six profiles. For MK22 and P1254 primers, 83 and 86% of the isolates, respectively, belonged to one profile only and the rest distributed among other 5 patterns. The findings of the present study showed that SE isolates from poultry-related sources were closely related to human SE isolates. This study confirmed previous evidence that molecular techniques such as RAPD-PCR or plasmid profile alone do not demonstrate sufficient discriminatory power in epidemiological studies and a combination of patterns obtained by several techniques will provide more discriminatory power.