First report of Haemaphysalis juxtakochi ticks in marsh deer (Blastocerus dichotomus) from Argentina

DANTE DI NUCCI ; DIANA ARNICA; IARA FIGINI; PAULA BLANCO; ELIANA GUILLEMI; MARÍA MARCELA OROZCO

Congreso; II Congreso de la Sociedad Latinoamericana de Ecología de Vectores; 2022

Universidad Nacional de La Plata

Vector-borne diseases represent 17% from whole infectious diseases and are responsible for more than 700.000 human deaths per year in the world. In this context, vector-borne disease drivers, including climate change, land use and land cover modifications, may contribute to higher incidence and wider geographic spread of vectors and vector-borne emerging pathogens. The recent emergence of several pathogens has highlighted the importance of wildlife disease surveillance for biodiversity conservation and global health. In the wetlands of northeastern Argentina, extraordinary floods have occurred frequently in recent years, including wildlife mortality events as for marsh deer (Blastocerus dichotomus). In this context, we have detected Theileria cervi, Trypanosoma theileri, Trypanosoma evansi, Ehrlichia chaffeensis, Anaplasma platys, A. marginale, A. odocoilei and Candidatus Anaplasma boolense in dead marsh deer. However, little is known about the wild transmission cycle of these pathogens in Argentina and the vectors involved have not been identified. High tick loads are frequent on marsh deer, and the species commonly found in individuals from argentine wetlands are Amblyomma triste and Rhipicephalus microplus. Dermacentor nitens and A. cajennense have been found feeding from marsh deer in the Brazilian Parana River region. As part of the wildlife health surveillance carried out since 2016, during 2019 we sampled nine marsh deer found dead in the Lower Delta of the Parana River. A fawn male of marsh deer with a high tick burden was reported. A total of 40 ticks were collected manually using acarological tweezers and stored in tubes containing 70º alcohol. The arthropods were taxonomically identified using a stereoscopic microscope (10X-40X, Nikon SMZ-2T) and taxonomic keys. All the 40 specimens corresponded to the species Haemaphysalis juxtakochi (18 adult males, 17 adult females and 5 nymphs). Haemaphysalis juxtakochi has been found parasitizing Mazama americana, M. gouazoubira, M. nana, Ozotoceros bezoarticus and Axis axis among other wild and domestic species in South America. In Argentina, the invasive species A. axis and cattle compete for territory with marsh deer, which means that these species could also be exposed to the same tick species. In this work we report the first finding of H. juxtakochi in marsh deer sampled in the Lower Delta of the Parana River.