Our group is focused on the development and transmission of phleboviruses (Phenuiviridae, Bunyavirales). This group of neglected viruses includes some medically and veterinary important pathogens. As a model organism we chose Toscana virus (TOSV), which is a human pathogen and infection can be asymptomatic or can have various manifestations, from febrile illness to infection of CNS with encephalitis or meningoencephalitis. The only proven vectors of TOSV are sand flies (Diptera, Phlebotominae) small insects of which both genders feed on plant sugar saps, but sand fly females feed also on blood of various vertebrates, including humans.

Although the importance and impact of TOSV on humans are very high, information about its biology and circulation in nature is lacking. There have not been confirmed any reservoir of infection; so far, it seems that vertical and horizontal transmission of TOSV between sand flies is not effective enough to maintain TOSV in nature. Despite these facts, TOSV circulate in a wide geographical area and is even spreading to new localities.

In the same geographical area as TOSV, the protozoa Leishmania infantum is transmitted by sand flies. This one-cell organism is a causative agent of the disease called visceral leishmaniasis. The relationship between TOSV and L. infantum, when co-infection or super-infection occurs in sand flies, can play a crucial role in the transmission and circulation of these two pathogens in nature. However, this phenomenon has not been studied so far.

The main aims of this group are as follows:

The development of TOSV in sand flies. By microscopy, molecular biology, and virological techniques, we are studying the possible ways of infection of sand flies by TOSV and also development of the virus in vector.

The vector competence of various sand fly species to TOSV. So far, only two species of sand fly, Phlebotomus perniciosus and Phlebotomus perfiliewi, have been proved as TOSV vectors. However, based on the geographical distribution of TOSV, other sand fly species will also be able to transmit TOSV. Due to the unique collection of sand fly species, which we have in the laboratory, we can test the vector competence of other sand fly species.

Co-infection and superinfection of TOSV and L. infantum. The appearance of more pathogens in sand fly can affect their development and transmission. Theoretically, there situation can happen: i) no effect on development of both pathogens, ii) at least one pathogen will profit from this co-infection, and iii) competition between these pathogens.