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Lancet Respir Med. 2014 Oct;2(10):813-22. doi: 10.1016/S2213-2600(14)70158-4. Epub 2014 Aug 28.

Tropism and replication of Middle East respiratory syndrome coronavirus from dromedary camels in the human respiratory tract: an in-vitro and ex-vivo study.

Author information

1
Centre of Influenza Research and School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Emerging Infectious Disease, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
2
Department of Microbiology and Parasitology, College of Veterinary Medicine, King Faisal University, Saudi Arabia; Department of Virology, Faculty of Veterinary Medicine, Kafrelsheikh University, Egypt.
3
Division of Virology, Department of Infectious Diseases, St Jude Children's Hospital, Memphis, TN, USA.
4
Department of Clinical Studies, College of Veterinary Medicine, King Faisal University, Saudi Arabia.
5
Center of Excellence for Influenza Viruses, National Research Center, Giza, Egypt.
6
Department of Pathology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. Electronic address: nicholls@pathology.hku.hk.
7
Centre of Influenza Research and School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; State Key Laboratory of Emerging Infectious Disease, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. Electronic address: malik@hku.hk.

Abstract

BACKGROUND:

Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic infection causing severe viral pneumonia, with index cases having resided in or recently travelled to the Arabian peninsula, and is a global concern for public health. Limited human-to-human transmission, leading to some case clusters, has been reported. MERS-CoV has been reported in dromedary camels but phenotypic characterisation of such viruses is limited. We aimed to compare MERS-CoV isolates from dromedaries in Saudi Arabia and Egypt with a prototype human MERS-CoV to assess virus replication competence and cell tropism in ex-vivo cultures of human bronchus and lung.

METHODS:

We characterised MERS-CoV viruses from dromedaries in Saudi Arabia and Egypt and compared them with a human MERS-CoV reference strain. We assessed viral replication kinetics and competence in Vero-E6 cells (rhesus monkey), tissue tropism in cultures of ex-vivo human bronchial and lung tissues, and cytokine and chemokine induction, gene expression, and quantification of viral RNA in Calu-3 cells (human respiratory tract). We used mock-infected tissue as negative controls for ex-vivo experiments and influenza A H5N1 as a positive control for cytokine and chemokine induction experiments in Calu-3 cells.

FINDINGS:

We isolated three dromedary strains, two from Saudi Arabia (Dromedary/Al-Hasa-KFU-HKU13/2013 [AH13] and Dromedary/Al-Hasa-KFU-HKU19D/2013 [AH19D]), and one from Egypt (Dromedary/Egypt-NRCE-HKU270/2013 [NRCE-HKU270]). The human and dromedary MERS-CoV strains had similar viral replication competence in Vero-E6 cells and respiratory tropism in ex-vivo cultures of the human respiratory tract, and had similar ability to evade interferon responses in the human-respiratory-tract-derived cell line Calu-3.

INTERPRETATION:

The similarity of virus tropism and replication competence of human and dromedary MERS-CoV from the Arabian peninsula, and genetically diverse dromedary viruses from Egypt, in ex-vivo cultures of the human respiratory tract suggests that dromedary viruses from Saudi Arabia and Egypt are probably infectious to human beings. Exposure to zoonotic MERS-CoV is probably occurring in a wider geographical region beyond the Arabian peninsula.

FUNDING:

King Faisal University, Egyptian National Research Centre, Hong Kong Food and Health Bureau, National Institute of Allergy and Infectious Diseases, and European Community Seventh Framework Program.

PMID:
25174549
DOI:
10.1016/S2213-2600(14)70158-4
[Indexed for MEDLINE]

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