December 27, 2013
MERS On The Rise, Kidney Failure Link Found, Camel Link Confirmed
Lawrence LeBlond for redOrbit.com - Your Universe Online
It is hard to tell if human cases of Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) are slowing down or speeding up. A total of seven new laboratory-confirmed cases of human infection with MERS-CoV have been reported to the World Health Organization (WHO) since Dec. 17, 2013.
According to a WHO report on Dec. 17, Saudi Arabia’s Ministry of Health (MOH) reported two laboratory-confirmed cases of infection with MERS-CoV. The first case was in a 51-year-old woman from Jawf province whose symptoms appeared on Nov. 20. She has underlying chronic disease and was placed in ICU in Riyadh. She has had no reported contact with animals.
The second case was a 26-year-old woman from Riyadh. She was asymptomatic and had reportedly been in contact with a 37-year-old male who was a previously lab-confirmed case reported on Nov. 21, 2013.
On Dec. 20, the MOH reported four additional lab-confirmed cases of MERS-CoV infection. This report, which was not officially released by the WHO until today, precedes a single case that was reported to the WHO on Dec. 22.
The Dec. 22 case involved a 68-year-old male from United Arab Emirates (UAE). The man was hospitalized on Dec. 14 following a cough after initially being hospitalized for surgery to replace a joint. He was moved to ICU on Dec. 16 because of rapid deterioration and officially diagnosed with MERS-CoV on Dec. 19, according to CIDRAP’s Robert Roos.
The man, who has underlying medical conditions, has had no recent history of travel or contact with animals or other MERS patients, according to the WHO. Investigations of the man’s family and healthcare workers continue.
In the Dec. 20-dated report, two additional cases of MERS-CoV are in female healthcare workers from Riyadh who have not yet reported any symptoms.
A third case is a 53-year-old man from Riyadh with underlying chronic diseases. He was hospitalized on Nov. 26 and is currently receiving treatment in ICU. He has had no exposure to animals and has not traveled outside the Riyadh region. He has had, however, contact with a confirmed case of MERS-CoV.
A fourth case occurred in a 73-year-old man from Riyadh with underlying chronic disease who died on Dec. 18, three days after hospitalization. He did have exposure to animals but no travel history.
The latest death from infection with MERS-CoV brings the total death count to 72, putting the mortality rate at about 42 percent. The mortality rate has remained fairly consistent at around 40 percent throughout the history of the disease.
In related news, Roos of CIDRAP reports that German researchers have found that MERS-CoV has a fondness for attacking human kidney cells.
Publishing a paper in Virology Journal, the researchers, led by Christian Drosten, MD, of the Institute of Virology, University of Bonn, say the evidence may explain why acute renal failure has been reported in some MERS-CoV cases.
For the study, Drosten and colleagues compared the effects of MERS-CoV and the SARS-CoV on cultures of primary human bronchial epithelial and primary human kidney cells.
“They found that pathogenic infection occurred only with MERS-CoV in the kidney cells and that kidney cells produced almost 1,000-fold more MERS-CoV copies than bronchial cells did,” wrote Roos.
Based on their findings, the team recommends that epidemiological studies should analyze kidney impairment in patients with MERS-CoV.
"Virus replication in the kidney with potential shedding in urine might constitute a way of transmission, and could explain untraceable transmission chains leading to new cases," the researchers wrote. "Individual patients might benefit from early induction of renoprotective treatment."
Last week, Reuters’ Kate Kelland reported that analysis of samples taken from camels with detected levels of MERS-CoV proves that the virus that is found in humans is the same strain as that found in camels, leading experts to potentially link camels as the source of the human outbreak.
Researchers from the Netherlands and Qatar conducted detailed gene-sequencing on three dromedary camels from a Qatari farm where two people also had contracted the MERS-CoV.
Publishing a paper in the journal Lancet Infectious Diseases, the team noted their work confirmed preliminary evidence released by Qatari health officials in November.
While camels are an important resource for people in the region, providing milk, meat and recreation, the researchers cautioned it is too early to say whether camels are definitely the source of at least the two human cases found at the farm.
"This is definitive proof that camels can be infected with MERS-CoV, but based on the current data we cannot conclude whether the humans on the farm were infected by the camels or vice versa," said Bart Haagmans, of Rotterdam's Erasmus Medical Centre, who led the study.
He added that there is a further possibility that humans and camels may have been infected from another as yet unknown source.
That source, while not mentioned in the Lancet study, may be bats, as another recent study has found a 100-percent genetic match to human MERS-CoV in a bat sample from the Middle East.
"The big unknown is the exact timing of infections, both in the persons and in the camels," Haagmans added. Both the men infected in Qatar recovered.