|Range of Hyalomma marginatum - ECDC|
The announcement yesterday (see below) from Spain's MOH that they had confirmed two locally acquired Crimean-Congo hemorrhagic fever infections in Western Europe - while surprising - was not completely unexpected.
The CCHV virus has been detected in local ticks since at least 2010, most likely carried in by migratory birds from Northern Africa (more on that in a bit).
First the announcement from Spain's MOH, followed by some background on CCHF, and then a look at this virus's creeping advance into Western Europe.
Confirmed two cases of Crimean-Congo hemorrhagic fever in Spain
September 1, 2016. The National Center for Microbiology Carlos III Institute of Health has confirmed two cases of Crimean-Congo hemorrhagic fever, first diagnosed in Spain. The first case is that of a patient, now deceased, who was treated at a hospital in Madrid. The second case is a woman ICU nurse who treated this same patient.
The Ministry of Health, Social Services and Equality is working with the Community of Madrid in everything related to the case. The Ministry has activated the protocol established by the National Network of Epidemiological Surveillance and coordination mechanisms with all regions.
The Crimean-Congo virus belongs to the Bunyaviridae family and is causing Crimean-Congo hemorrhagic fever. This virus has a natural cycle in ticks that act as vectors whose main reservoir is wild and domestic ruminants. The disease is endemic in Africa, the Balkans, Middle East and Asia.
Media reports indicate the MOH is monitoring up to 200 people - mostly hospital employees - who have been in contact with these patients.
CCHF is normally transmitted to humans via the bite of a tick - most commonly Hyalomma marginatum - or via contact with the blood of infected animals, although there have been reports of nosocomial (in hospital) transmission as well (see 2010 WHO report on Pakistan).
As you can see from the map above, the virus is most commonly found in Eastern Europe, Central Asia, and parts of Africa. Until now, Western Europe has only seen a handful of imported cases (see UK PHE Reports Imported Case Of CCHF and Crimean-Congo Hemorrhagic Fever Patient Isolated In Glasgow).
According to the ECDC:
In Europe cases of human infections have been reported from Albania, Armenia, Bulgaria, Kazakhstan, Kosovo, Russia, Serbia, Tajikistan, Turkey, Turkmenistan, Ukraine, and Uzbekistan. In June 2008, a first case was diagnosed in Greece.
But in 2010 alarm bells rang when researchers detected the presence of CCHV in ticks collected in and around Cáceres, in the western part of Spain. This discovery was reported in the CDC's EID Journal in 2012.
Crimean-Congo Hemorrhagic Fever Virus in Ticks, Southwestern Europe, 2010
Agustín Estrada-Peña, Ana M. Palomar, Paula Santibáñez, Nely Sánchez, Miguel A. Habela, Aránzazu Portillo, Lourdes Romero, and José A. Oteo corresponding author
We report the detection of CCHFV in ticks collected in southwestern Europe. A total of 117 semi-engorged adult H. lusitanicum ticks were collected from 28 adult red deer (Cervus elaphus) in November 2010, at a site (39.63°N, 7.33°W) in Cáceres, Spain.
This finding suggests the circulation of CCHFV in southwestern Europe. The close affinity of the strain from Spain with strains circulating in western Africa and the lack of similarity with isolates from eastern Europe suggest the introduction of this virus from nearby countries of northern Africa.
Migratory movements of birds could explain the presence of the virus in southwestern Europe because birds are common hosts of immature H. marginatum, which was reportedly introduced into Europe through annual migratory flights along the western coast of Africa (10). Because of the lack of genetic similarities among virus strains, trade movements of domestic or wild ungulates from eastern Europe do not support our finding.
(Continue . . . )
Similar reports were reported the following year, also in the EID Journal, in Crimean-Congo Hemorrhagic Fever Virus in Ticks from Migratory Birds, Morocco, with their abstract reading:
Crimean-Congo hemorrhagic fever virus was detected in ticks removed from migratory birds in Morocco. This finding demonstrates the circulation of this virus in northwestern Africa and supports the hypothesis that the virus can be introduced into Europe by infected ticks transported from Africa by migratory birds.
With a competent vector (see Hyalomma marginatum range map) already in place, and repeated introductions of the CCHF virus by tick carrying migratory birds, the ECDC has been alert to the possibility of seeing locally acquired cases for years.
While autochthonous infection with CCHF in Western Europe is likely to remain a rare event, this now means that doctors there will have to consider another rare and exotic pathogen in their differential diagnoses.
And this adds yet another reason why every healthcare facility – large and small - needs to plan, train and equip themselves for the possibility that the next patient that comes to their ER could be carrying something considerably more exotic and dangerous than the flu.