Matas-Méndez, Pablo, Ávalos, Gabriel, Caballero-Gómez, Javier, Dashti, Alejandro, Castro-Scholten, Sabrina, Jiménez-Martín, Débora, González-Barrio, David, Muñoz-de-Mier, Gemma J., Bailo, Begoña, Cano-Terriza, David, Mateo, Marta, Nájera, Fernando, Xiao, Lihua, Köster, Pamela C., García-Bocanegra, Ignacio, and Carmena, David
Simple Summary: The Iberian lynx is an iconic feline species endemic to the Iberian Peninsula. Since the second half of the past century, its global population has decreased dramatically to the brink of extinction as a consequence of human-driven activities (habitat reduction and transformation, illegal hunting, road kills, density decrease in natural preys) and infectious diseases. Fortunately, the successful implementation of conservation programs has reversed this gloomy trend, allowing for an increase in the Iberian lynx population to over 1600 free-ranging animals in 2022. Regarding infectious diseases, very little is known on the epidemiology and health impact of the diarrhoea-causing intestinal protozoan parasites Cryptosporidium and Giardia in the Iberian lynx. To tackle these questions, we investigated the presence and molecular diversity of both pathogens in 256 collected faecal samples from 251 free-ranging and captive Iberian lynxes in Spain during the period 2017–2023. Our results demonstrate that Cryptosporidium (2.4%) and Giardia (27.9%) are present at different frequencies in the surveyed individuals. Our molecular analyses also indicate that a significant proportion of the Cryptosporidium infections detected are caused by strains that are typically found in the preys the Iberian lynx feed on. Interestingly, we also found that the Iberian lynx can harbour genetic variants of Cryptosporidium and Giardia with the potential to infect humans, although the likelihood of such events is judged low due to the light infections detected in the investigated animals. Cryptosporidium spp. and Giardia duodenalis are the main non-viral causes of diarrhoea in humans and domestic animals globally. Comparatively, much less information is currently available in free-ranging carnivore species in general and in the endangered Iberian lynx (Lynx pardinus) in particular. Cryptosporidium spp. and G. duodenalis were investigated with molecular (PCR and Sanger sequencing) methods in individual faecal DNA samples of free-ranging and captive Iberian lynxes from the main population nuclei in Spain. Overall, Cryptosporidium spp. and G. duodenalis were detected in 2.4% (6/251) and 27.9% (70/251) of the animals examined, respectively. Positive animals to at least one of them were detected in each of the analysed population nuclei. The analysis of partial ssu rRNA gene sequences revealed the presence of rodent-adapted C. alticolis (n = 1) and C. occultus (n = 1), leporid-adapted C. cuniculus (n = 2), and zoonotic C. parvum (n = 2) within Cryptosporidium, and zoonotic assemblages A (n = 5) and B (n = 3) within G. duodenalis. Subgenotyping analyses allowed for the identification of genotype VaA19 in C. cuniculus (gp60 locus) and sub-assemblages AI and BIII/BIV in G. duodenalis (gdh, bg, and tpi loci). This study represents the first molecular description of Cryptosporidium spp. and G. duodenalis in the Iberian lynx in Spain. The presence of rodent/leporid-adapted Cryptosporidium species in the surveyed animals suggests spurious infections associated to the Iberian lynx's diet. The Iberian lynx seems a suitable host for zoonotic genetic variants of Cryptosporidium (C. parvum) and G. duodenalis (assemblages A and B), although the potential risk of human transmission is regarded as limited due to light parasite burdens and suspected low excretion of infective (oo)cysts to the environment by infected animals. More research should be conducted to ascertain the true impact of these protozoan parasites in the health status of the endangered Iberian lynx. [ABSTRACT FROM AUTHOR]