Title : The role of aedes koreicus in the circulation of dirofilaria repens and dirofilaria immitis filarial nematodes in a middle-sized european city, in Hungary
The mosquito-borne pathogens are present worldwide, notable among these are Dirofilaria immitis, which causes heartworm disease, and Dirofilaria repens, known as the causative agent of subcutaneous dirofilariasis. These two species are unfortunately endemic throughout Europe and are well known pathogens in animal health.
In addition, the emergence, more efficient and faster spread of invasive mosquito species may further increase this risk. Invasive species can compete with native species for limited resources, alter habitats, reduce biodiversity, introduce new diseases into an area and can also be a potential vector of an already present pathogen. One of Hungary's invasive mosquito species is Aedes koreicus, which has been present in one of the southwestern cities (Pécs) for years, has been under continuous monitoring since its emergence, and more data on its spatio-temporal dynamics and ecological requirements are available every year.
Our aim in this study was to monitor the population of Aedes invasive and other common mosquito species in the area identified as a focus of infection, including an animal shelter, and in several locations within the city of Pécs, and to test the collected mosquitoes for Dirofilaria species. In addition, we aimed to investigate the dependence of mosquito infestation on weather, location and species with particular attention to Ae. koreicus.
In terms of our results, we processed more than 300 pools of mosquito samples collected in the 2022 season by qRT-PCR, including common species and invasive Ae. koreicus, as well as blood fed individuals. Our positive samples for filarial parasites include both Ae. koreicus and common species as well (Aedes vexans, Culex pipiens and Ochlerotatus sticticus etc.) collected from different trap sites, and the pathogen was also detected in the head-thorax part of blood fed Ae. vexans. In the light of our preliminary results we have not found a clear correlation between the spread of Ae. koreicus and Dirofilaria infestation of mosquitoes. However D. repens is rarely but capable of infecting humans, and recently several human cases have been described in Pécs from close proximity to each other and coinciding with the most favourable urban areas for Ae. koreicus. Thus, we plan to extend our work by processing further samples and to investigate the circumstances of the human cases.
The exploration of this phenomenon is also of paramount importance from a practical point of view, as understanding the underlying determinants of human disease provides an opportunity for preventive interventions, and this research design aims to provide a basis for this.