Dengue virus (DENV) is a so-called Arbovirus. Arboviruses are viruses that are transmitted by arthropods, like flies, ticks, and mosquitos. One of the BPRC research lines focuses on emerging arboviruses transmitted by mosquitos. These mosquito-borne viruses include clinically relevant viruses like Dengue Virus (DENV), Yellow Fever Virus (YFV), Chikungunya virus (CHIKV), Rift Valley Fever virus (RVFV), Japanese encephalitis virus (JEV), and the West Nile virus (WNV).
Since the 1960-ies, DENV has expanded its global distribution considerably, and in more recent years other mosquito-borne viruses have spread to new geographic areas, most dramatically exemplified by the introductions of WNV and CHIKV on the American continent.
Global spread of DENV since 1960
Factors that contribute to the ongoing spread of mosquito-borne viruses include global warming, leading to an increase of suitable areas for mosquito vectors, and international trade and travel. The latter have resulted in the introduction of new, invasive mosquito species like the tiger mosquito (Aedes albopictus), an important vector for DENV, CHIKV, and the less-known Zika virus (ZIKV) in Europe and America. Equally, the mosquito Aedes aegypti, carrier for DENV, CHIKV and YFV has recently been introduced on Madeira and in countries around the Black sea. Other viruses, like WNV and RVFV can make use of a spectrum of invasive and endemic insect vectors, mostly Culex and Aedes species.
In humans, mosquito-borne virus infections can lead to severe, and sometimes life-threatening diseases, including encephalitis, paralysis, and hemorrhagic disease. To date, YFV and JEV are the only mosquito-borne viruses for which a vaccine for use in humans is available, but no vaccines and antiviral compounds are available for important diseases caused by DENV and other rapidly emerging viruses like WNV, CHIKV, and RVFV.
ARBOVIRUS RESEARCH AT THE BPRC
Macaques and common marmosets can be infected with mosquito-borne viruses and offer researchers unique insights into the biology and virus-induced pathological events. Additionally, because of their immunological similarity to humans, they are well-accepted animal models for the preclinical evaluation of vaccine candidates or antiviral compounds. WNV and DENV infection models of rhesus macaques and common marmosets are used at the BPRC to study the pharmacokinetics and efficacy of antivirals compounds, and to evaluate the immunogenicity and efficacy of prototype vaccines. Cell culture systems are being used for the in vitro characterization of the vaccine-induced antibody immune responses. Additional research is focused on the events that take place early in the infection, a phase of the infection that cannot be studied in humans.