High Prevalence of Middle East Respiratory Coronavirus in Young Dromedary Camels in Jordan

Abstract

Prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) was determined in 45 dromedary camels from two geographically separated herds in Jordan. Virus shedding was only detected in swabs obtained from the respiratory tract and primarily observed in camels younger than 3 years. MERS-CoV seroprevalence increased with age of camels. Bovine and sheep sera were seronegative. Phylogenetic analysis of partial S2 clustered the Jordanian MERS-CoV strains with contemporary MERS-CoV strains associated with nosocomial outbreaks.

Keywords: Jordan; MERS-CoV; dromedary camel; phylogeny; serology.

FIG. 1.

MERS-CoV prevalence in dromedary camels in Jordan. (A) Locations of dromedary camels (north: Ramtha; east: Azraq). (B) Percentage of MERS-CoV RNA shedding dromedary camels as detected by UpE and ORF1A qRT-PCR assay in nasal swab, stratified by age. (C) Percentage of MERS-CoV S1-specific seropositive dromedary camels, stratified by age. (D) ELISA ratio of seropositivity of dromedary camels, stratified by age. The ELISA ratio was calculated by dividing the OD of each serum sample by a constant positive sample on the ELISA plate. ELISA, enzyme-linked immunosorbent assay; Middle East respiratory syndrome coronavirus (MERS-CoV), OD, optical density.

FIG. 2.

Phylogenetic analysis of a partial spike S2 domain. A maximum likelihood tree based on the GTR+G+I model using 1000 bootstraps was generated from a spike S2 domain genome fragment corresponding to nucleotides 23781–24395 of HCoV-EMC/2012. The newly identified MERS-CoV sequences are depicted in bold, recent MERS-CoV sequences associated with an outbreak in Jordan in 2015 are depicted in bold. Bootstrap values of <50 were not shown.