A participatory surveillance of marsh deer (Blastocerus dichotomus) morbidity and mortality in Argentina: first results.

BACKGROUND: In an era of unprecedented socio-ecological changes, managing wildlife health demands high-quality data collection and the engagement of local communities. Blastocerus dichotomus, the largest South American deer, is Vulnerable to extinction mainly due to habitat loss. Diseases have been recognised as a potential threat, and winter mortality has been historically described in marsh deer populations from Argentina. Field difficulties have, however, prevented in-depth studies of their health status. RESULTS: Between May 2014 and April 2017, we investigated marsh deer morbidity and mortality in the two largest populations in Argentina. We collected data by means of a passive surveillance system that involved a network of researchers, field partners (veterinarians, park rangers, and local community), and decision makers. We sampled marsh deer during as well as outside mortality events. A total of 44 marsh deer with different body condition scores were evaluated. We obtained haematology and biochemistry values from animals with good body condition score. Marsh deer with poor body condition had a high burden of the ticks Amblyomma triste and Rhipicephalus microplus. Vector-borne agents such as Theileria cervi, Trypanosoma theileri, Trypanosoma evansi, Ehrlichia chaffeensis, Anaplasma platys, Anaplasma odocoilei, Anaplasma marginale, and Candidatus Anaplasma boleense were also found. Haemonchus spp., Ostertagia spp., and Trichostrongylus spp. were the most frequent gastrointestinal parasites in deer with poor body condition. A Multiple Correspondence Analysis reinforced a possible association of winter period with lower body score condition, high tick loads, infection with E. chaffeensis, and presence of harmful gastrointestinal parasites. CONCLUSIONS: Our approach allowed the establishment of a participatory surveillance network of marsh deer morbidity and mortality in Argentina. We report and analyse the first data obtained opportunistically within the framework of this network, providing information on the infectious and parasitic agents in marsh deer populations. The occurrence of Fasciola hepatica and Leptospira interrogans serovar pyrogenes is reported for the first time in wild marsh deer from Argentina. Our data will be useful to improve the interpretation of future mortality events. The field implementation of a surveillance network is key to a holistic approach to wildlife diseases.

Co-administration of Na-EDTA and diminazene aceturate (DA) to mice infected with DA-resistant Trypanosoma brucei.

This study investigated the effects of co-administration of Na-EDTA and diminazene aceturate (DA) on the level of parasitaemia (LOP), parasite clearance, packed cell volume (PCV) and post-infection survival time (PIST) in mice infected with DA-resistant Trypanosoma brucei. Five groups of 10 mice were treated as follows: infected and treated with Na-EDTA+DA; infected and treated with DA alone; infected and treated with Na-EDTA alone; infected-untreated; and uninfected-untreated. The co-administration of Na-EDTA and DA led to reduced LOP and improvements in PCV (P<0.05), as compared with treatment with DA alone. Mice treated with Na-EDTA+DA had a marginally (P>0.05) higher PIST than did mice treated with DA alone. Comparison of the group given Na-EDTA alone with the infected-untreated group showed that the former group had a significantly lower (P<0.01) LOP, improved PCV (P<0.05) and higher (P<0.01) PIST. It was concluded that the co-administration of Na-EDTA and DA led to a slight potentiation of DA in the treatment of mice infected with DA-resistant T. brucei, and that the administration of Na-EDTA alone significantly enhanced the resistance of the infected mice.