Olli Vapalahti Research Group

Our projects aim to elucidate the molecular epidemiology, natural cycles, pathogenesis and disease associations of zoonotic and arbovirus infections and to develop means for their detection. We target both local pathogens - tick-borne encephalitis (TBEV), Puumala hantavirus and Sindbis virus (SINV) infections, which are the most important endemic zoonotic viruses in Northern Europe, as well as globally important pathogens, such as dengue and zika viruses, and novel emerging pathogens.

A specific target is the Taita-Taveta region in Kenya, where University of Helsinki has a research station. We search further for determinants associated with pathogenicity, host specificity and human outbreaks of flaviviruses (TBEV, dengue, zika viruses), SINV and hantaviruses and host-virus interaction from molecular and cellular to population level. Furthermore, we are developing new diagnostic modalities such as metagenomics as a tool to unravel causative agents of human and veterinary infectious diseases (whether zoonoses or not) and characterizing disease associations. For example we have recently shown that two orthobunyaviruses cause encephalitis for human in Finland, and provided key evidence that zika virus causes fetal brain abnormalities in humans, and that arenavirus coinfections cause Boid inclusion body disease and that A. phocae is main pathogen causing Fur Animal Epidemic Necrotic Pyoderma (FENP).

In specific projects we target NGS as a diagnostic tool (Helsinki University Hospital funds), dengue and arboviruses in Eastern Africa (Academy of Finland), Ebola virus diagnostics (EU Innovative Medicines Initiative) and Aleutian Disease, FENP and parvoviruses and diarrhea causing agents in foxes (FFBA and VetCare), and have general arbo- and zoonotic virus projects funded by Sigrid Jusélius Foundation and Helsinki University Hospital Funds.

We employ the One Health concept in our approaches and e.g. collect and screen arthropod, bird, rodent and other wildlife samples in addition to human patients for viral antibodies, antigen and/or nucleic acids, and characterize the viruses and strains using molecular methods, including traditional sequencing and in house NGS data (lllumina MiSeq) analysis.

Classical virology techniques with infectious virus (e.g. virus isolation in cell culture, neutralization assays) are performed in biosafety level (BSL 2-3) laboratories maintained by our group. Novel assays are developed based on recombinant antigens and e.g. a new FRET (Förster Resonance Energy Transfer) concept, real-time amplification assays and new sequencing methodologies and evaluated with large sample panels. Virus-host cell interactions are studied using infected cell cultures, transfected viral genes and recombinant viruses.

The projects involve collaborative studies with human and veterinary clinicians, wildlife ecologists, several research institutes and universities abroad.

These include collaborators at UH and Helsinki University Hospital, Natural Resources Institute Finland (LuKe), Evira, FinFurLab, Universities of Tampere, Kuopio, Uppsala, Umeå, Zürich, Marseille, São Paulo, Karolinska Institute, L'Institut Pasteur, Bernhard Nocht Insitute for Tropical Medicine, Hamburg, Erasmus Medical Center, Rotterdam, EVD-LabNet (Emerging Viral Diseases Laboratory Network), Reagena LTD and Vetcare.

Viral zoonooses group/ Olli Vapalahti


Tarja Sironen (hantaviruses, fur animal pathogens, phylogeny)
Eili Huhtamo (Mosquito-borne viruses, flaviviruses)
Jussi Hepojoki (Hanta and Arenaviruses)
Teemu Smura (NGS, virus discovery)
Tomas Strandin (Hantaviruses)
Kristian Forbes (Rodent and bat-borne viruses)
Lev Levanov (TBEV reporter assays, flaviviral serodiagnostics)
Satu Hepojoki (FRET assay development)
Erika Lindh
Anne Jääskeläinen (Diagnostics) (HUSLAB)
Satu Kurkela (Sindbis) (HUSLAB)
Anu Jääskeläinen (TBEV) (HUSLAB)
Hannimari Kallio-Kokko (Diagnostics) (HUSLAB)

PhD (or Master's) Students:
Kirsi Aaltonen (Fur animal pathogens)
Jenni Virtanen (Amdoviruses)
Heli Nordgren (FENP)
Essi Korhonen (née Hasu) (dengue, zika)
Lorna Culverwell (Entomology, arboviruses)
Suvi Kuivanen (TBEV, ZIKV, innate immunity)
Rommel Iheozor-Ejiofor (Hantaviruses)
Moses Masika (Arboviruses in Kenya)
Lauri Kareinen (FRET diagnostics)
Ilkka Kivistö (bat-borne pathogens)
Samuel Adouchef (SINV)
Alma Helisten (ZIKV)
Yegor Korzyukov (Snake arenaviruses)

Irina Suomalainen
Johanna Martikainen
Sanna Mäki