Qatari MERS patient dies; WHO offers case-control study guide

United States Mission Geneva/Flikr

A Qatari man who had lain in a London hospital with a severe MERS-CoV (Middle East respiratory syndrome coronavirus) case since last September died last week, it was reported today, while the World Health Organization (WHO) released a study protocol designed to help investigators figure out how the deadly virus is reaching humans.

The Qatari man died Jun 28, according to a report from the British newspaper The Telegraph, which cited an official at Guy's and St. Thomas' Hospital in London. The man's illness was one of the first two MERS cases to come to light. He was 49 when his case was first reported.

"Guy's and St Thomas' can confirm that the patient with severe respiratory illness due to novel coronavirus (MERS-nCV) sadly died on Friday 28 June, after his condition deteriorated, despite every effort and full supportive treatment," said Robin Wilkinson, a spokesman for the hospital, as quoted by the newspaper.

According to earlier reports, the Qatari man had traveled to Saudi Arabia sometime before he fell ill on Sep 3, 2012. He was put in intensive care in Qatar on Sep 7 and then was flown by air ambulance to London on Sep 11, where he was placed in a hospital intensive care unit.

The new coronavirus first gained major global attention on Sep 23 (2012), when the WHO issued a statement about the Qatari man's illness and that of a 60-year-old Saudi Arabian man who had died in June of that year. (The first public mention of the novel virus came on Sep 20, when a doctor in Saudi Arabia used ProMED to report discovering the virus in the Saudi patient.)

Unofficially, the Qatari man's death raises the global MERS death toll to 43, out of 77 cases. Saudi Arabia announced the deaths of two other patients yesterday. Those deaths have not yet been noted by the WHO, whose last MERS update on Jun 26 listed the count at 77 cases and 40 deaths.

Meanwhile, the WHO today released a detailed protocol for case-control studies aiming to identify the risk factors for infection with MERS-CoV, other than exposure to known case-patients. The original animal or environmental source of the virus and exactly how it jumps to humans remain mysterious.

The stated purpose of the 21-page protocol is to "identify modifiable non-human exposures that lead to MERS-CoV infection."

"Although finding the putative animal reservoir is an important step in controlling spread of the virus, a more immediate need is to understand the route and mode of transmission to humans, and the types of exposures that result in infection," the document states.

"Several possibilities exist, including direct contact with an infected animal, which could be either the reservoir species or an intermediate host species; contact with or consumption of unprocessed animal products; contact with the environment where an infected animal has recently been; or consumption of a food or beverage which has been contaminated by animal excreta."

The protocol follows a standard case-control design in which investigators use interviews and questionnaires to find differences in exposures between persons with confirmed MERS-CoV cases and healthy controls. Questionnaires include detailed queries on travel history, human exposures, animal exposures, and foods consumed.

The document offers guidance on each phase and aspect of a case-control study, from population and subject recruitment to ethical considerations, outcome measures, and statistical analyses.

The protocol was adapted from one developed by the Consortium for the Standardization for Influenza Seroepidemiology (CONSISE), a global partnership that works to develop influenza investigation protocols and to standardize seroepidemiology to inform public health policy for pandemic, zoonotic, and seasonal influenza. The partnership was created out of a need, identified during the 2009 H1N1 pandemic, for better data to estimate attack rates and severity of the pandemic virus.

Also today, the WHO released a revised definition for probable MERS-CoV cases, based on recent data. The new version spells out three combinations of criteria for a probable case.

Key factors in the definition include evidence of pulmonary parenchymal disease, such as pneumonia or acute respiratory distress syndrome; test results, if any; direct links to a confirmed case; and residence in or a history of recent travel to the Middle East.

The revised definition is broader than the previous one, released Feb 19, which did not mention a connection to the Middle East.

The WHO defines a case as confirmed only if lab tests have revealed the virus.

See also:

WHO's Jul 3 case-control study protocol

WHO's Jul 3 revised case definition

WHO's previous case definition, released Feb 19

Jul 3 Telegraph story on death of Qatari in UK

Sep 24, 2012, CIDRAP News story describing Qatari case

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