Evaluación de la presencia y carga parasitaria en heces de zorros Culpeo y Chilla que cohabitan con carnívoros domésticos de libre tránsito en la región de Los Lagos, Chile.
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Date
2025
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Universidad de Concepción
Abstract
La presencia de carnívoros domésticos de libre tránsito en hábitats compartidos con fauna silvestre representa un potencial riesgo para la transmisión de patógenos. En este estudio, se evaluó la relación entre la presencia de perros y gatos de libre tránsito (mediante el uso de un proxy de presencia de carnívoros domésticos) y la presencia y carga parasitaria en zorros culpeo (Lycalopex culpaeus) y chilla (Lycalopex griseus) en la región de Los Lagos, Chile. Se planteó la hipótesis de que la proximidad a carnívoros domésticos aumentaría la carga y la presencia de parásitos en zorros. Para ello, se recolectaron y analizaron 50 muestras de heces de zorros, perros y gatos, identificando la especie hospedadora mediante análisis genético y la presencia y carga parasitaria a través de técnicas coproparasitológicas. Se utilizó análisis espacial en QGIS para estimar la presencia de carnívoros domésticos mediante la creación de un proxy, considerando variables como la distancia a la casa más cercana, densidad de viviendas dentro de un buffer específico para cada especie de zorro, porcentaje de bosque nativo (como indicador de pérdida de hábitat por antropización) y la presencia/ausencia de carnívoros domésticos, determinada a partir de registros visuales, recolección de heces y cámaras trampa. Posteriormente, se aplicaron modelos GLM en R para evaluar la relación entre la carga y presencia de parásitos con estas variables. Se identificaron los géneros Trichuris, Taenia, Toxocara y ooquistes de coccidios, con L. culpaeus presentando mayor prevalencia de Trichuris y Taenia, mientras que L. griseus mostró mayor presencia de coccidios, Toxocara y Trichuris. Sin embargo, los modelos estadísticos no evidenciaron una relación significativa entre la presencia de carnívoros domésticos y la carga o presencia de parásitos en zorros. Estos resultados sugieren que otros factores, como el tamaño muestral, la variabilidad en la distribución de parásitos, la desparasitación de carnívoros domésticos y la ecología del hospedador, podrían estar modulando esta interacción. Se recomienda ampliar el muestreo e incluir variables adicionales para evaluar con mayor precisión el impacto de los carnívoros domésticos en la transmisión parasitaria a la fauna silvestre.
The presence of free-roaming domestic carnivores in habitats shared with wildlife represents a potential risk for pathogen transmission. In this study, we evaluated the relationship between the presence of free-roaming dogs and cats (using a proxy for the presence of domestic carnivores) and the presence and parasite load in culpeo (Lycalopex culpaeus) and chilla (Lycalopex griseus) foxes in the Los Lagos region, Chile. It was hypothesized that proximity to domestic carnivores would increase the load and presence of parasites in foxes. For this purpose, 50 fecal samples from foxes, dogs and cats were collected and analyzed, identifying the host species through genetic analysis and the presence and parasite load through coproparasitological techniques. Spatial analysis in QGIS was used to estimate the presence of domestic carnivores by creating a proxy, considering variables such as distance to the nearest house, density of dwellings within a specific buffer for each fox species, percentage of native forest (as an indicator of habitat loss due to anthropization) and the presence/absence of domestic carnivores, determined from visual records, feces collection and camera traps. Subsequently, GLM models in R were applied to evaluate the relationship between the load and presence of parasites with these variables. Trichuris, Taenia, Toxocara and coccidial oocysts were identified, with L. culpaeus showing higher prevalence of Trichuris and Taenia, while L. griseus showed higher presence of coccidia, Toxocara and Trichuris. However, the statistical models did not show a significant relationship between the presence of domestic carnivores and the load or presence of parasites in foxes. These results suggest that other factors, such as sample size, variability in parasite distribution, domestic carnivore deworming and host ecology, could be modulating this interaction. We recommend expanding sampling and including additional variables to more accurately assess the impact of domestic carnivores on parasite transmission to wildlife.
The presence of free-roaming domestic carnivores in habitats shared with wildlife represents a potential risk for pathogen transmission. In this study, we evaluated the relationship between the presence of free-roaming dogs and cats (using a proxy for the presence of domestic carnivores) and the presence and parasite load in culpeo (Lycalopex culpaeus) and chilla (Lycalopex griseus) foxes in the Los Lagos region, Chile. It was hypothesized that proximity to domestic carnivores would increase the load and presence of parasites in foxes. For this purpose, 50 fecal samples from foxes, dogs and cats were collected and analyzed, identifying the host species through genetic analysis and the presence and parasite load through coproparasitological techniques. Spatial analysis in QGIS was used to estimate the presence of domestic carnivores by creating a proxy, considering variables such as distance to the nearest house, density of dwellings within a specific buffer for each fox species, percentage of native forest (as an indicator of habitat loss due to anthropization) and the presence/absence of domestic carnivores, determined from visual records, feces collection and camera traps. Subsequently, GLM models in R were applied to evaluate the relationship between the load and presence of parasites with these variables. Trichuris, Taenia, Toxocara and coccidial oocysts were identified, with L. culpaeus showing higher prevalence of Trichuris and Taenia, while L. griseus showed higher presence of coccidia, Toxocara and Trichuris. However, the statistical models did not show a significant relationship between the presence of domestic carnivores and the load or presence of parasites in foxes. These results suggest that other factors, such as sample size, variability in parasite distribution, domestic carnivore deworming and host ecology, could be modulating this interaction. We recommend expanding sampling and including additional variables to more accurately assess the impact of domestic carnivores on parasite transmission to wildlife.
Description
Tesis presentada para optar al título de Biólogo/a.
Keywords
Parasitología, Zorros Chile, Salud animal