# 8549
On a day when the new Saudi Minister of Health appears to be taking the MERS-Camel connection more seriously (see Crofsblog Saudi Arabia: Faqih urges avoidance of camel meat and milk), we get a new study appearing in the open-access journal mBio that further implicates camels as the source of the virus.
Researchers report recovering MERS-CoV from nasal swabs of dromedaries whose complete genetic sequences are indistinguishable from those found in humans. Furthermore, they found that camels can be simultaneously infected with multiple strains of MERS.
The study, led by an international team from Columbia University , King Saud University, and the EcoHealth Alliance, found the MERS virus in 3/4ths of the camels they tested.
Middle East Respiratory Syndrome Coronavirus Quasispecies That Include Homologues of Human Isolates Revealed through Whole-Genome Analysis and Virus Cultured from Dromedary Camels in Saudi Arabia
Thomas Briesea, Nischay Mishraa, Komal Jaina, Iyad S. Zalmoutb, Omar J. Jabadoc, William B. Kareshd, Peter Daszakd, Osama B. Mohammedb, Abdulaziz N. Alagailib,e, W. Ian Lipkina
ABSTRACT
Complete Middle East respiratory syndrome coronavirus (MERS-CoV) genome sequences were obtained from nasal swabs of dromedary camels sampled in the Kingdom of Saudi Arabia through direct analysis of nucleic acid extracts or following virus isolation in cell culture. Consensus dromedary MERS-CoV genome sequences were the same with either template source and identical to published human MERS-CoV sequences. However, in contrast to individual human cases, where only clonal genomic sequences are reported, detailed population analyses revealed the presence of more than one genomic variant in individual dromedaries. If humans are truly infected only with clonal virus populations, we must entertain a model for interspecies transmission of MERS-CoV wherein only specific genotypes are capable of passing bottleneck selection.
IMPORTANCE In most cases of Middle East respiratory syndrome (MERS), the route for human infection with the causative agent, MERS coronavirus (MERS-CoV), is unknown. Antibodies to and viral nucleic acids of MERS-CoV have been found in dromedaries, suggesting the possibility that they may serve as a reservoir or vector for human infection. However, neither whole viral genomic sequence nor infectious virus has been isolated from dromedaries or other animals in Saudi Arabia. Here, we report recovery of MERS-CoV from nasal swabs of dromedaries, demonstrate that MERS-CoV whole-genome consensus sequences from dromedaries and humans are indistinguishable, and show that dromedaries can be simultaneously infected with more than one MERS-CoV. Together with data indicating widespread dromedary infection in the Kingdom of Saudi Arabia, these findings support the plausibility of a role for dromedaries in human infection.
In an accompanying press release, Columbia University's Mailman School of Public Health quotes authors Thomas Briese, Abdulaziz N. Alagaili, and Ian Lipkin on the findings:
"The finding of infectious virus strengthens the argument that dromedary camels are reservoirs for MERS-CoV," says first author Thomas Briese, PhD, associate director of the Center for Infection and Immunity and associate professor of Epidemiology at the Mailman School. "The narrow range of MERS viruses in humans and a very broad range in camels may explain in part the why human disease is uncommon: because only a few genotypes are capable of cross species transmission," adds Dr. Briese.
"Given these new data, we are now investigating potential routes for human infection through exposure to camel milk or meat products," says co-author Abdulaziz N. Alagaili, PhD, director of the Mammals Research Chair at King Saud University. "This report builds on work published earlier this year when our team found that three-quarters of camels in Saudi Arabia carry MERS virus."
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"Although there is no evidence that MERS-CoV is becoming more transmissible, the recent increase in reported cases is a cause for concern," says senior author W. Ian Lipkin, MD, director of the Center for Infection and Immunity and the John Snow Professor of Epidemiology at the Mailman School. "It is essential that investigators commit to data and sample sharing so that this potential threat to global health is addressed by the entire biomedical research community."
Looks like its time for Ian Mackay to break out his smoking camel graphic again.
