The effect of excluding ungulates on the abundance of ixodid ticks on wild rabbit (Oryctolagus cuniculus).

Tick abundance depends heavily on host density, so reducing access to the host should reduce tick populations in a determined area. In this study we compared the Parasitic Index (PI = average number of ticks per rabbit) of two wild rabbit populations separated 16 years ago by a fence keeping ungulates from moving freely. Two areas were selected (closed and open) wherein 50 wild rabbits per area were sampled for ticks. The PI in the open area (PI = 989.62) was significantly higher than in the closed area (PI = 515.40). Hyalomma lusitanicum Koch was globally the most abundant species, followed by Rhipicephalus pusillus Gil Collado, Rhipicephalus bursa Canestrini and Fanzago, Haemaphysalis hispanica Gil Collado, Rhipicephalus sanguineus s.l. Latreille and Ixodes ventalloi Gil Collado. Differences between areas varied depending on the species. The number of H. hispanica, R. bursa and R. pusillus were significantly more abundant on rabbits in the closed area, whereas H. lusitanicum predominated in the open area. Ungulates in the open area may have played an important role as the main or alternative host for ticks and/or drawing some tick species away from rabbits. In the closed area other reasons such as inter-specific competition could have influenced the tick abundance. These results show a clear reduction in tick abundance for at least 16 years as well as influenced species distribution.

Seasonal dynamics of ixodid ticks on wild rabbits Oryctolagus cuniculus (Leporidae) from Central Spain.

Rabbit Hemorrhagic Disease and Myxomatosis caused a decline in the rabbit population in the second half of the last century. Despite some recovery, the risk of vector-borne disease is present and thus the importance of controlling vector populations. In the current study, we describe the ixodid tick fauna in wild rabbit in a natural reserve in Ciudad Real (Central Spain) during the course of two 3-year periods (2007-2009 and 2012-2014). Of all the ticks collected on average 72.5 % were larvae, 24.4 % nymphs and 3.1 % adults, although the percentage varied monthly. Seven tick species were identified: Hyalomma lusitanicum Koch (Parasitic indicator [PI] = number of ticks per examined rabbit = 96.47), Rhipicephalus pusillus Gil Collado (PI = 47.37), Haemaphysalis hispanica Gil Collado (PI = 12.15), Ixodes ventalloi Gil Collado (PI = 0.65), R. bursa Canestrini and Fanzago (PI = 0.18), R. sanguineus Latreille (PI = 0.11), Dermacentor marginatus Sulzer (PI = 0.01). In spring and summer, most abundant were larvae of H. lusitanicum, followed by immature stages of R. pusillus and Ha. hispanica. In autumn, the main tick species were nymphs of I. ventalloi whereas in winter adults of Ha. hispanica were more numerous. Rhipicephalus pusillus was present all year long, although not always in high percentage. PI of other species (R. bursa, R. sanguineus and D. marginatus) were too low to be representative. The seasonal dynamics of ticks on wild rabbit defined in this study could be useful to design species-specific control strategies.

Control of Hyalomma lusitanicum (Acari: Ixodidade) Ticks Infesting Oryctolagus cuniculus (Lagomorpha: Leporidae) Using the Entomopathogenic Fungus Beauveria bassiana (Hyocreales: Clavicipitaceae) in Field Conditions.

Entomopathogenic fungi are widely used to control arthropods not just in agricultural settings but also in Veterinary Medicine and Public Health. These products have been employed to control tick populations and tick-borne diseases. The effectiveness of these control measures not only depends on the fungi, but also on the tick species and environmental conditions. In Mesomediterranean areas, tick species are adapted to extreme climatic conditions and it is therefore especially important to develop suitable tick control strategies. The aim of this study was to evaluate the effectiveness of a new method of tick control which entails the application of a commercial strain of Beauveria bassiana (Balsamo, Vuillemin) on wild rabbit burrows under field conditions. Aqueous solutions of the product were applied using a mist blower sprayer into 1,717 burrows. Two trials were performed, one in spring and the other in summer. The parasitic index (PI) was calculated for 10 rabbits per treatment per time point on day +30, +60, and +90 posttreatment and efficiency was calculated by comparing the PI for ticks in treated and untreated rabbits. A total of 20,234 ixodid ticks were collected. Hyalomma lusitanicum Koch, 1844 was the most abundant tick feeding on rabbits. Treatment significantly reduced the PI in spring (by 78.63% and 63.28% on day +30 and +60, respectively; P < 0.05), but appeared to be less effective in summer, with a marginally significant tick reduction of 35.72% on day +30 (P = 0.05). Results suggest that the efficacy of applications inside burrows could be temperature-dependent and that such applications could be an economic alternative to rabbit tick control during at least two months using a diluted solution of B. bassiana conidia.

Long term study of ixodid ticks feeding on red deer (Cervus elaphus) in a meso-Mediterranean climate.

Red deer (Cervus elaphus L.) are very valuable in trophy-hunting but also contribute to the preservation of natural areas. They are affected by many parasites and pathogens, including hard ticks that are not only important parasites themselves but can also act as vectors and/or reservoirs of pathogens. Tick phenology is complex insofar as population dynamics depend on environmental conditions, vegetation, host availability and their own intrinsic characteristic. Ticks were collected monthly from January 2007 to December 2014 from red deer on a natural reserve located in a meso-Mediterranean environment in Central Spain. A total of 8978 specimens of ixodid ticks were recovered with a mean Parasitization Index of 65.06 ticks/deer. Red deer were infected the whole year round with a summer-spring pattern and two secondary peaks in February and October. The main species was Hyalomma lusitanicum Koch followed by Rhipicephalus bursa Canestrini and Fanzago, Rhipicephalus pusillus Gil Collado, Dermacentor marginatus Sulzer and Ixodes ricinus L. Hyalomma lusitanicum has a complex life cycle in which several generations initiate their cycle at different times throughout the year, most probably lasting more than 1 year. We also describe the ability of nymphs to feed on large ungulates even though their habitual host is wild rabbit.