Travel-related MERS-CoV cases: an assessment of exposures and risk factors in a group of Dutch travellers returning from the Kingdom of Saudi Arabia, May 2014.

Ewout B Fanoy,Douwe Van Der Werf,Charlie Van Der Weijden,Kees Dirksen,Jolande W Bouwhuis,Marleen Kraaij-Dirkzwager,Marcel Jonges,Arianne B Van Gageldonk-Lafeber,Wim Van Der Hoek,Marion Pg Koopmans,Gerard Sonder,Marianne Ab Van Der Sande,Luc Gelinck,Jet Van Der Heuvel

doi:10.1186/1742-7622-11-16

Abstract

BackgroundIn May 2014, Middle East respiratory syndrome coronavirus (MERS-CoV) infection, with closely related viral genomes, was diagnosed in two Dutch residents, returning from a pilgrimage to Medina and Mecca, Kingdom of Saudi Arabia (KSA). These patients travelled with a group of 29 other Dutch travellers. We conducted an epidemiological assessment of the travel group to identify likely source(s) of infection and presence of potential risk factors.MethodsAll travellers, including the two cases, completed a questionnaire focussing on potential human, animal and food exposures to MERS-CoV. The questionnaire was modified from the WHO MERS-CoV questionnaire, taking into account the specific route and activities of the travel group.ResultsTwelve non-cases drank unpasteurized camel milk and had contact with camels. Most travellers, including one of the two patients (Case 1), visited local markets, where six of them consumed fruits. Two travellers, including Case 1, were exposed to coughing patients when visiting a hospital in Medina. Four travellers, including Case 1, visited two hospitals in Mecca. All travellers had been in contact with Case 1 while he was sick, with initially non-respiratory complaints. The cases were found to be older than the other travellers and both had co-morbidities.ConclusionsThis epidemiological study revealed the complexity of MERS-CoV outbreak investigations with multiple potential exposures to MERS-CoV reported such as healthcare visits, camel exposure, and exposure to untreated food products. Exposure to MERS-CoV during a hospital visit is considered a likely source of infection for Case 1 but not for Case 2. For Case 2, the most likely source could not be determined. Exposure to MERS-CoV via direct contact with animals or dairy products seems unlikely for the two Dutch cases. Furthermore, exposure to a common but still unidentified source cannot be ruled out. More comprehensive research into sources of infection in the Arabian Peninsula is needed to strengthen and specify the prevention of MERS-CoV infections.

Highlights

In May 2014, Middle East respiratory syndrome coronavirus (MERS-CoV) infection, with closely related viral genomes, was diagnosed in two Dutch residents, returning from a pilgrimage to Medina and Mecca, Kingdom of Saudi Arabia (KSA)
In 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) was isolated for the first time from the sputum of a 60-year-old man who presented with an acute pneumonia in Kingdom of Saudi Arabia (KSA) [1]
For most non healthcare associated cases no clear source of infection could be identified, camels are considered a reservoir as the virus and antibodies against MERS-CoV have been identified in camels (Camelus dromedarius) and in their milk [9,10]

Summary

Introduction

In May 2014, Middle East respiratory syndrome coronavirus (MERS-CoV) infection, with closely related viral genomes, was diagnosed in two Dutch residents, returning from a pilgrimage to Medina and Mecca, Kingdom of Saudi Arabia (KSA). These patients travelled with a group of 29 other Dutch travellers. Mainly sporadic cases are reported as well as a few hospital outbreaks, which is in line with a low reproduction rate (R0) of MERS-CoV, estimated to range from 0.4 to 1.5 [8,9,10]. To stop or reduce transmission of MERS-CoV and prevent new human infections, it is important to identify all potential sources of infections as well as risk factors and route(s) of transmission

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