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

DI NUCCI, D.; ARNICA, D; FIGINI, I; BLANCO, P; GUILLEMI, G; OROZCO, MM

Congreso; II Congress of the Latin American Society for Vector Ecology; 2022

Vector-borne diseases represent 17% from whole infectiousdiseases and are responsible for more than 700.000 humandeaths per year in the world. In this context, vector-bornedisease drivers, including climate change, land use and landcover modifications, may contribute to higher incidence andwider geographic spread of vectors and vector-borne emergingpathogens. The recent emergence of several pathogens hashighlighted the importance of wildlife disease surveillance forbiodiversity conservation and global health. In the wetlands ofnortheastern Argentina, extraordinary floods have occurredfrequently in recent years, including wildlife mortality events asfor marsh deer (Blastocerus dichotomus). In this context, wehave detected Theileria cervi, Trypanosoma theileri,Trypanosoma evansi, Ehrlichia chaffeensis, Anaplasma platys,A. marginale, A. odocoilei and Candidatus Anaplasma boolensein dead marsh deer. However, little is known about the wildtransmission cycle of these pathogens in Argentina and thevectors involved have not been identified. High tick loads arefrequent on marsh deer, and the species commonly found inindividuals from argentine wetlands are Amblyomma triste andRhipicephalus microplus. Dermacentor nitens and A.cajennense have been found feeding from marsh deer in theBrazilian Parana River region. As part of the wildlife healthsurveillance carried out since 2016, during 2019 we samplednine marsh deer found dead in the Lower Delta of the ParanaRiver. A fawn male of marsh deer with a high tick burden wasreported. A total of 40 ticks were collected manually usingacarological tweezers and stored in tubes containing 70º alcohol.The arthropods were taxonomically identified using astereoscopic microscope (10X-40X, Nikon SMZ-2T) andtaxonomic keys. All the 40 specimens corresponded to thespecies Haemaphysalis juxtakochi (18 adult males, 17 adultfemales and 5 nymphs). Haemaphysalis juxtakochi has beenfound parasitizing Mazama americana, M. gouazoubira, M.nana, Ozotoceros bezoarticus and Axis axis among other wildand domestic species in South America. In Argentina, theinvasive species A. axis and cattle compete for territory withmarsh deer, which means that these species could also beexposed to the same tick species. In this work we report the firstfinding of H. juxtakochi in marsh deer sampled in the Lower Deltaof the Parana River.