A camel herd in Qatar that had Middle East respiratory syndrome coronavirus (MERS-CoV) infections associated with two human MERS cases now seems to be free of the virus, Qatari authorities reported yesterday via the World Organization for Animal Health (OIE).
"The samples from the same herd tested using the same technique were negative and this may show that MERS-CoV infection in camels is a self-limiting disease," a Qatari agriculture official said in the OIE report.
Three of 14 camels in the herd had tested positive for the virus, according to findings reported by Qatari health officials in late November. The camels were tested in October, after MERS-CoV was diagnosed in their 61-year-old owner and in a 23-year-old man who worked on the farm.
Scientists found that the camel viruses were nearly identical to the viruses in the two patients, according to a separate report published 2 weeks ago in the Lancet Infectious Diseases. But they couldn't determine if the camels had passed the virus to the humans or vice versa, or if some other host had infected both camels and humans.
Further results awaited
The OIE report did not specify when the camel samples that tested negative were collected. Earlier reports had mentioned plans to test other animals and environmental samples from the same farm, but the OIE report did not mention any other results.
It said a planned national survey looking for MERS-CoV in animals is "under implementation," and the camel herd "is under systematic retesting," with follow-up reports to be submitted when new findings emerge. Qatari authorities were working on the investigation with experts from Erasmus Medical Center in Rotterdam and the Netherlands' National Institute for Public Health and the Environment.
The camels on the farm all appeared healthy or showed only mild signs of illness when they were initially tested in October, the World Health Organization said in reporting the findings on Nov 29.
Camels are the leading suspects in the hunt for the source of MERS-CoV in humans, but the case against them is not yet clear. Saudi Arabian officials reported on Nov 11 that they had found the virus in a camel owned by a Jeddah man who was infected, but they have not yet published a scientific report on the finding.
Sorting Saudi cases
In other developments, an English-language statement from the Saudi Ministry of Health (MOH) has verified an earlier media report of five new MERS-CoV cases in that country. The report raises the number of new cases reported in Saudi Arabia since Dec 20 to nine.
The new MOH report is dated Dec 25 but apparently was posted over the weekend; the Dec 25 date may refer to when the Arabic-language version was posted. The similarity of some of the patients' ages and the lack of details in Arabic and English-language reports from the MOH had previously left it unclear whether some of the case reports were new or repetitions of previous ones.
The cases cited in the latest MOH statement involved:
- A 57-year-old male Saudi citizen who has chronic diseases and was in an intensive care unit
- A 73-year-old Saudi man who died
- A 43-year-old resident healthcare worker
- A 35-year-old resident healthcare worker
- A 27-year-old healthcare worker who is a citizen
The three healthcare workers, who had no symptoms, were exposed to MERS-CoV patients, the statement said.
Ziad A. Memish, MD, Saudi Arabia's deputy minister of public health, confirmed that the country has reported nine distinct cases since Dec 20, according to a summary posted yesterday by ProMED-mail, the reporting service of the International Society for Infectious Diseases. The two fatalities among those cases both involved 73-year-old men.
Saudi Arabia's MERS count now stands at 141 cases, with 57 deaths.
Dec 29 OIE report from Qatar
Dec 16 CIDRAP News story "Nearly identical MERS-CoV strains found in camels, humans"
Dec 2 CIDRAP News story on infected Qatar camels
Dec 25 Saudi MOH statement on five cases
Dec 20 Saudi MOH statement on four cases
Dec 29 ProMED-mail post on Saudi cases
Saudi MOH MERS page with case count