Characterising African tick communities at a wild–domestic interface using repeated sampling protocols and models

Abstract

The sharing of habitat by wild and domestic animals may result in pathogen transmission, notably via ectoparasite vectors such as ticks. Interfaces between protected and communal lands constitute sharp transitions between areas occupied by host communities that are extremely contrasted in terms of com-position, diversity and density. Empirical characterizations of tick communities and of their vertebrate hosts are strongly relevant for understanding the mechanisms leading to disease transmission between wild and domestic animals. In the present study we aimed at depicting the pattern of spatial variation in the density of immature ticks at such an interface located in Zimbabwe. At the end of the 2011 rainy season, we applied a hierarchical repeated protocol to collect ticks. We used the dragsampling method in the vegetation surrounding water pans used by ungulates in 3 distinct landscape compartments (i.e. national park, mixed compartment and communal lands) characterized by a differential use by wild and domestic hosts. We combined generalized linear mixed models with site occupancy models to (1) assess tick aggregation levels at different spatial scales, (2) identify and disentangle factors which influence the density and probability of tick detection, and (3) compare robust estimations of tick densities among the landscape compartments. Ticks belonging to the Amblyomma and Riphicephalus genuses were found to be the most abundant. At small scale, ticks were more often detected in the afternoon and were more abun-dant close to water pans for Amblyomma and Riphicephalus genuses. Riphicephalus spp. density was also higher in grassland and bushland vegetation types as compared to woodland vegetation type. At large scale, for the three detected genuses, density was much higher near water pans located in the communal lands as compared to the national park and mixed compartment. Given that host community's diversity is much lower in the communal areas than in the two other landscape compartments, these results are compatible with a dilution effect but not sufficient to demonstrate this effect without additional studies. Up to date, it is the first utilization of these rigorous sampling and statistical modelling methodologies to estimate tick density in African ecosystem simultaneously at large and small scales.

Spatial and seasonal patterns of FMD primary outbreaks in cattle in Zimbabwe between 1931 and 2016

“…The largest national park in Zimbabwe, Hwange, hosts a large buffalo population. This area is classified by the Zimbabwean government also as a semi-arid zone, hosts significant livestock populations (Figure 1) and is also recognized as part of a regional cluster of FMD strains [45] and wildlife/livestock interactions do occur with potential for disease transmission as well [12, 46, 47]. Therefore, what makes the SEL more prone to FMD outbreaks compared to other similar zones such as the Matabeleland region?…”

Priorización de enfermedades virales zoonóticas en la interfaz de cerdos silvestres, cerdos domésticos y seres humanos

“…Según la priorización, las tres enfermedades zoonóticas con mayor puntuación (cuadros 2 y 5) en general y de acuerdo con la categoría (cuadro 6), fueron la influenza porcina (133), la hepatitis E (123) y la infección por hantavirus (103).…”

“…La transmisión de microorganismos patógenos puede darse como resultado del movimiento de animales silvestres y animales domésticos entre hábitats, lo cual ocurre en sitios en los que convergen estas especies con el hombre, en áreas protegidas o en áreas comunes que constituyen un punto de confluencia de patógenos oportunistas involucrados en la presentación de enfermedades, y cuya composición, diversidad y densidad afectan el desarrollo natural de las especies en cuanto a la interacción con su entorno. De ahí la importancia de entender esta interfaz y el mecanismo de transmisión de patógenos en las áreas comunes para los animales domésticos, los animales silvestres y los seres humanos, con el fin de analizar el riesgo local y global que implican (103).…”

Looking for Ticks from Space: Using Remotely Sensed Spectral Diversity to Assess Amblyomma and Hyalomma Tick Abundance

“…Several studies pointed out how avian biodiversity and abundance is positively associated to spectral diversity in savanna landscapes (see for instance [56,57]). Interestingly, Hyalomma species [73,74], but also A. variegatum [75], have been shown to parasitize small mammals and birds in immature stages, while the adults parasitize mainly ungulates and cattle. The host preferences of both Amblyomma spp.…”