New research has identified some key differences between the Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS.

The findings, published in The Lancet Infectious Diseases, detail the viral load profile of MERS-CoV, giving a complete explanation of how it circulates though the body.

MERS-CoV has a 60% death rate. However, according to researchers, there is no evidence of widespread human-to-human MERS-CoV transmission.

Update: June 17th, 2013 – Saudi Arabia announced four more deaths from MERS-CoV infection, bringing the death toll in the country to 32. Thirty-seven people have died from MERS-CoV infection worldwide.

The report details the case of a 73 year old man from Abu Dhabi who died from MERS-CoV infection.

There are limited data on the MERS-CoV and the man in Abu Dhabi is the fifth patient whose progression of the virus has been examined and reported in a medical journal.

Two days after developing flu-like symptoms, the patient in Abu Dhabi went to hospital and was diagnosed with pneumonia, he was treated with antibiotics and artificial ventilation.

After 12 days, he was taken to a hospital in Munich, Germany, where he experienced severe respiratory problems and kidney failure. He died shortly after arriving.

The researchers measured the patient’s viral load after admission to the hospital. They identified viral load to be highest in the lower respiratory tract, but also found low and detectable viral loads in urine and stool samples.

In fact, the investigators believe that the reason why two of the patients who suffered from the virus also had kidney failure is because the presence of the virus in urine means it is able to replicate in the kidney.

However, the patients were also given antibiotics in the early stages of their illness which could have also affected kidney function.

Stool samples had low concentrations of the virus, which indicates a key difference between how the virus works compared to the severe acute respiratory syndrome (SARS) coronavirus – which had high levels of the virus in stool samples.

The authors said that understanding more about how MERS-CoV circulates will have huge potential for infection control.

Professor Christian Drosten, a lead author of the study, said: “Laboratory data like these are critical to reach recommendations for diagnostics, to make projections about the prognosis of the patient, as well as to estimate infection risks”

He added:

“In the absence of qualitative laboratory data from well-documented MERS cases, most of these considerations were up to now made upon an assumed analogy to SARS. However, we’re now finding that certain elementary traits of the MERS virus appear to be different to SARS.”

Co-lead author, Professor Clemens-Martin Wendtner, concluded:

“With only five complete genome sequences so far available there is an urgent need for more genetic data to reveal the spatial and temporal distribution of these cases, estimate the number of independent human chains of transmission, and thus better evaluate the threat this virus poses to world health.”

Margaret Chan, the Director-General of the World Health Organization (WHO) warned that MERS-CoV is a “threat to the entire world”.

MERS-CoV has killed 33 people and infected 58 worldwide so far, according to WHO. Twenty-eight of those deaths have occurred in Saudi Arabia.

Written by Joseph Nordqvist