Report of a new meq gene size: The first study on genetic characterisation of Marek’s disease viruses circulating in Iranian commercial layer and backyard chicken

ABSTRACT

1. In recent months, several outbreaks with clinical signs of MDV-1 were reported in Iranian parent and laying hen farms, in addition to backyard chickens. Several meq gene sequences from these outbreaks were amplified and molecularly characterised.

2. The meq protein sequences revealed three different sizes, namely the standard 339 aa, a shorter form of 338 aa lacking a proline residue at position 191, and a very short (vs) size of 265 aa. Based on sequence and size, the 265 aa meq has never been reported from international research groups before. The protein has only one PPPP repeat motif suggesting it belongs to a highly virulent strain.

3. The standard meq sequences showed 100% BLAST identity to the vv+ isolate Polen5. However, the 338 aa form clustered to the clade usually reported from North America.

4. This is the first report on genetic analysis of MDV-1 from Iran, but further study is required to obtain a better picture of the diversity and prevalence of different MDV-1 strains circulating in the country’s farms, backyard poultry and other bird species.

KEYWORDS:

• Marek’s disease
• Iran
• chicken farms
• clade
• meq gene
• PPPP
• virulence

Author contributions

AM performed the experiments, carried out all the computer analyses and wrote the manuscript. AGH and HH provided resources and scientific support, revised the manuscript. AB and MMA prepared samples and provided resources. FE ran PCR and gel electrophoresis. ZZ revised the manuscript and provided resources. SB and EA provided scientific support and samples. LA and KR collected samples. MHFM, MA and AS supervised the project, provided funding and resources. SHEL reviewed and revised the manuscript. VN provided scientific support and revised the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental data for this article can be accessed here.

Additional information

Funding

The research was funded by Razi Vaccine and Serum Research Institute.