Crimean-Congo Hemorrhagic Fever, Spain, 2013-2021

Abstract

Crimean-Congo hemorrhagic fever (CCHF) is a viral infectious disease for which distribution of the main vector, Hyalomma spp. ticks, is expanding. We analyzed all 10 cases of CCHF diagnosed in Spain during 2013-2021; case-patient median age was 56.5 years, and 7 were men. We identified CCHF virus genotypes III and V. Six case-patients acquired the infection in urban areas. Sixty percent of patients were infected in summer and 40% in spring. Two patients met criteria for hemophagocytic syndrome. Seven patients survived. The epidemiologic pattern of CCHF in Spain is based on occasional cases with an elevated mortality rate. Genotype III and, to a less extent also genotype V, CCHF circulates in humans in a common geographic area in Spain. Those data suggest that the expansion pathways are complex and may change over time. Physicians should remain alert to the possibility of new CCHF cases.

Keywords: Crimean-Congo hemorrhagic fever virus; Spain; hemorrhagic fever; tick-borne infections; viruses; zoonoses.

Figure 1

Locations of CCHF cases (A) and phylogenetic tree of CCHFV (B) in Spain, 2013–2021. Dots on the map indicate patients with a CCHF diagnosis in Spain: black dots indicate cases from this study, and colored dots indicate cases previously described. Two cases (patients 8 and 10) were not sequenced. The phylogenetic tree was constructed by the neighbor-joining method based on sequences of the small segment of the virus. The numbers on the right indicate bootstrap values for the groups; values <75 are not shown. Other sequences are listed by GenBank accession number, strain, geographic origin, and sampling year. Genotypes are indicated by Roman numerals according to Carroll et al. (14) with the equivalent clade nomenclature according to Chamberlain et al. (15) in brackets; I, West Africa (Africa 1); III, South and West Africa (Africa 3); IV, Middle East/Asia, divided into 2 groups (Asia 1/Asia 2); V, Europe/Turkey (Europe 1); VI, Greece (Europe 2). New lineage, Africa 4 described by Negredo et al. (12). CCHF, Crimean-Congo hemorrhagic fever; CCHFV, CCHF virus.

Figure 2

Images of patients in study of Crimean-Congo hemorrhagic fever, Spain, 2013–2021. A) Details of a slightly purpuric rash on the leg of patient 8. B) Ecchymosis on the arm of patient 5. C) Mild rash on the chest of patient 9.

Figure 3

Bone marrow biopsy findings from patient 5 (A) and patient 9 (B) in study of Crimean-Congo hemorrhagic fever, Spain, 2013–2021. Arrows indicate macrophages with hemophagocytosis phenomena of red blood cells and platelets.