Thelazia callipaeda and its Drosophilid Intermediate Host

Dogs in southern Europe are often infested with the oriental eyeworm. This eye worm originates from Asia and is transmitted by special fruit flies that ingest tear. In Europe, it is spreading northwards, favoured by climate change and globalisation. In addition to dogs, many other animals and humans can also be affected. This project aims to clarify several questions about the fruit fly vector and its interaction with the eye worm. Which fruit fly species can act as vector? One species has been identified as vector in Europe. A closely related species, which is widespread in Europe, has not been investigated so far. In another species, the development of eye worm larvae could be demonstrated in the laboratory. However, this species is not known to feed on tear fluid and would therefore biologically not be a suitable vector. Furthermore, it is not known if a development could take place in distantly related species like the ubiquitous fruit fly Drosophila. Using CT (computed tomography for very small objects like insects), the development of the eye worm larvae in the body of the fruit fly will be demonstrated and three dimensional reconstructed. By that the question whether there is a difference in the development in biological suitable and biological non-suitable fruit fly vectors will be clarified. Furthermore, the project will clarify if eye worm larvae recognise the type of food the fruit fly is ingesting and subsequently leaves the fruit fly targeted to infect a new host. To answer these questions, the respective fruit flies will be collected in the field and then bred in the laboratory. By feeding eye worm larvae, the fruit flies will be infected. These larvae will be obtained from eye worms, which are collected during routine treatment of infected dogs in endemic regions. This project is therefore supported by research partners from the University of Bari, Italy.