Institutions of RICET Carlos III Health Institute Biological Research Centre Ramon y Cajal Hospital López Neyra Parasitology and Biomedicine Institute Severa Ochoa Molecular Biology Centre, Autónoma University of Madrid La Laguna University Léon University Murcia University Salamanca University Valencia University

Emerging Viral Diseases

Manager: Antonio Tenorio ISCIII-D

This programme's main research goals are:

Imported Viral Diseases

From the inception of laboratory activities, impetus was given to research into imported viral diseases, in collaboration with clinical research groups linked to the RICET. This study has yielded results of maximum interest on

o Dengue Virus: with a proposal being generated for molecular surveillance of circulation of serotypes and genotypes potentially associated with outbreaks of haemorrhagic disease. At present, studies are being conducted on European travellers in collaboration with European tropical medicine (European Network on Imported Infectious Disease Surveillance - TropNet Europe) and virology (European Network for Diagnostics of Imported Viral Diseases - ENIVD) networks. Research is also being done in hyper-endemic areas, with retrospective studies in Colombia and Peru and probably in Central America, Venezuela and Ecuador in the near future.

o Chikungunya Virus: Although previous research studies associated with projects in the RICET context enabled the circulation of the Chikungunya virus to be detected in Guinea Ecuatorial, research interest in Spain and other European countries has increased enormously ever since the apparent emergence new variants that seem to be better adapted to replication in the vector Aedes albopictus, which recently appeared in Spain and which has settled in other European Mediterranean countries. These new variants, which came about through evolution of the l lineage that previously circulated in East Africa, have displaced previously circulating lineages in different countries across Continental Africa and India, and have caused epidemic outbreaks with enormous morbidity-mortality and economic impact on islands in which this virus had never before been in circulation. Research, currently targeted at generating diagnostic toools and characterising the evolutionary variants in circulation, is being undertaken in close collaboration with Spanish clinical groups linked to the RICET and the Pasteur Institute (Unité de Biologie des Infections Virales Emergentes - UBIVE, Lyon, France). Its application to imported cases detected in Spain and other European countries will make it possible for molecular surveillance of the circulation and spatial-temporal evolution of the different lineages to be implemented.

o Yellow Fever Virus: Together with the above viruses, theoretically-speaking this too could come to be transmitted in Spain by Aedes albopictus (recently established in some Mediterranean districts) and, theoretically, bring about outbreaks, such as that caused in the 19th century in Spain's island territories and mainland, with the death toll in the hundreds of thousands. Research has been targeted at improving diagnostic methods, undertaking studies on virus evolution and, in particular, investigating the side effects of the attenuated vaccine, in collaboration with research groups linked to the RICET and the Robert Koch Institute in Berlin.

New potentially emerging or re-emerging viruses in wild vectors and reservoirs.

To date, this line of research has enabled abundant sequences in vectors and reservoirs to be identified, viz.,

- Flavivirus: Argentine Saint Louis (San Luis) Encephalitis Virus. At least 15 new species of flavivirus in Spain, Equatorial Guinea, Argentina and Uruguay.
- Phlebovirus: Toscana phlebovirus in Spain and Sandfly fever Sicilian virus in Greece and Algeria. Two species of phlebovirus not described until now in Spain and positive results in other European countries (France, Albania and Greece).
- Alphavirus: Chikungunya Virus in Equatorial Guinea.
- Arenavirus: A variant of the lymphocytic choriomeningitis virus in wild rodents in Spain

and surprisingly,

- An Ebola virus, retrospectively detected among bats in caves situated in northern Spain, which would define a fifth evolutionary variant within the ebolaviruses , with still unknown pathogenicity though probably associated with other non-pathogenic variants described in Asia.

In view of the recent and surprising nature of these results, studies have been initiated, specifically targeted at additionally characterising some of these viruses, particularly:

ebola

- - A flavivirus whose genomic sequences are evolutionarily associated with the antigenic group of the yellow fever virus
  - A phlebovirus with sequences that group together with other phleboviruses that infect humans
  - The Ebolavirus detected in bats (in collaboration with European level BSL-4 laboratories)
"Tropical" viruses in Spain

Spain has a geographical situation that renders it especially susceptible to being home to arthropod-vectors or reservoir-borne viruses. Indeed, the fact that diseases such as malaria, yellow fever and dengue (two of which caused serious outbreaks in the 19th century) have disappeared from this country is essentially due to unknown factors that influenced the disappearance of its principal vector, Aedes aegypti. Unfortunately, recent years have seen the detection of various foci of an alternative vector, Aedes albopictus, which acts as an effective vector of chikungunya and dengue in the Indian and Pacific regions. Although they have generally gone unnoticed, other viruses also continue to circulate in this country. Among those that are known, evidence has been obtained in recent years of diseases caused by the following viruses in Spain, for which specific research projects are kept in place:

- West Nile Virus:
  - Studies on circulation of the virus in Spain. Development of wide-spectrum methods for detection of the various known viral lineages. Characterisation of the virulence of the respective lineages of West Nile virus in animal models. Obtainment of an infectious clone that can be used for identification of sequences associated with pathogeny and attenuation.
- Toscana Phlebovirus:
  - Development of wide-spectrum methods for efficacious detection of the various known viral lineages. Characterisation of the Spanish genotype of the Toscana virus. Identification of reservoir. Virus/vector co-evolution studies. Clinical spectrum of the infection.
- Lymphocytic Choriomeningitis Virus:
  - Development of methodology for sensitive detection of new variants detected for the lymphocytic choriomeningitis virus in Spain. Molecular characterisation of the new variants. Identification of geographic areas affected by the infection. Virus/reservoir co-evolution studies. Identification of risk factors for infection.