LAUSR

The Darwin's fox (Lycalopex fulvipes) is one of the most endangered carnivores worldwide, with the risk of disease spillover from domestic dogs being a major conservation threat. However, lack of epidemiologic information about generalist, non-dog-transmission-dependent protozoal and bacterial pathogens may be a barrier for disease prevention and management. To determine the exposure of some of these agents in Darwin's fox populations, 54 serum samples were collected from 47 Darwin's foxes in Southern Chile during 2013-18 and assessed for the presence of antibodies against Brucella abortus, Brucella canis, Coxiella burnetii, pathogenic Leptospira (serovars Grippotyphosa, Pomona, Canicola, Hardjo, and Copehageni), Toxoplasma gondii, and Neospora caninum. The highest seroprevalence was detected for T. gondii (78%), followed by pathogenic Leptospira (14%). All the studied Leptospira serovars were confirmed in at least one animal. Two foxes seroconverted to Leptospira and one to T. gondii during the study period. No seroconversions were observed for the other pathogens. No risk factors, either intrinsic (sex, age) or extrinsic (season, year, and degree of landscape anthropization), were associated with the probability of being exposed to T. gondii. Our results indicate that T. gondii exposure is widespread in the Darwin's fox population, including in areas with minimal anthropization, and that T. gondii and pathogenic Leptospira might be neglected threats to the species. Further studies identifying the causes of morbidity and mortality in Darwin's fox are needed to determine if these or other pathogens are having individual or population-wide effects in this species.