Investigation of Ixodid ticks as vectors of Babesia caballi and Theileria equi (Protozoa: Apicomplexa) in central Italy

Abstract

Babesia caballi and Theileria equi are widely recognized as causative agents of equine pirolasmosis (EP), an acute, sub‐acute, and chronic disease of equines, with relevant economic impact on horse trade worldwide. Although several studies on EP prevalence from central Italy have been published, data on ticks responsible for its transmission are still lacking. In this study, we identified a potential competent vector, investigating main features of its ecology together with EP infection rates. A two‐year sampling of questing ticks was carried out for the first time in Italy in an area known for high EP prevalence in horse sera, detecting the association between Rhipicephalus bursa and causative agents of EP. Most of the positive pools harbored a single infection (91.1%); mixed infections were also detected (8.9%). The infection rate for T. equi slightly decreased among years; B. caballi showed a lower, but increasing, infection rate. Tick phenology, climate variables, and peaks of EP prevalence indicated late May and second half of June as periods with the highest risk of new infections, especially during warm and dry days.

Eco‐epidemiology of equine piroplasmosis and its associated tick vectors in Europe: A systematic literature review and a meta‐analysis of prevalence

“…The highest prevalence of B. caballi (6%) was recorded in Bulgaria in H. marginatum collected on cattle (Nader et al., 2018). An even higher percentage of 19% was reported in Italy in R. bursa collected on vegetation, but the detection was performed on pools of ticks hindering direct comparison (Romiti et al., 2020). Regarding T. equi , the highest prevalence (14%) was recorded in Spain in questing R. bursa ticks collected on vegetation ( García‐Sanmartin et al., 2008).…”

“…Regarding T. equi , the highest prevalence (14%) was recorded in Spain in questing R. bursa ticks collected on vegetation ( García‐Sanmartin et al., 2008). An even higher percentage of 49% was again reported in Italy, also in R. bursa collected on vegetation, but the detection was performed on pools of ticks and cannot be directly compared (Romiti et al., 2020).…”

Spatial and Temporal Circulation of Babesia caballi and Theileria equi in France Based on Seven Years of Serological Data

“…This heterogeneity may be linked to more favourable conditions for B. caballi and T. equi vectors in southern France, with higher vector density and/or activity linked to a more favourable climate. For instance, vegetation cover, land use, rainfall and temperature have a direct effect on the presence and the abundance of ticks, with fluctuations according to the tick species [44][45][46]. Dermacentor reticulatus, Dermacentor marginatus, and Rhipicephalus bursa are the main vectors of B. caballi and T. equi in France.…”

The specificity of Babesia-tick vector interactions: recent advances and pitfalls in molecular and field studies

“…tavsan 2 1 (11%) Israel Harrus et al [ 177 ] Rhipicephalus turanicus (83 pools) 1.2% MIR Babesia vogeli , one pool (1.2%) PCR sequencing (pools) Rhipicephalus sanguineus (48 pools) 4.2% MIR B. vogeli , two pools (4.2%) Hyalomma spp. (13 specimens) 0% - Italy Romiti et al [ 152 ] Rhipicephalus bursa (980 in 110 pools) 14.6% pools B. caballi , 16 pools (14.5%) qPCR with TaqMan probe for B. caballi Japan Masatani et al [ 178 ] a Haemaphysalis formosensis (159) 1.3% Babesia sp. (feral raccoon strain) (1.3%) PCR sequencing Haemophysalis flava (191) 1.6% Babesia sp.…”

“…and one Amblyomma . In two recent studies, B. caballi was found in 16 pools of R. bursa in Italy (Table 2 ; [ 152 ]) and in seven D. nuttalli from Mongolia [ 153 ]. Such a variety of tick species might reflect the ability of B. caballi to adapt to transmission in parts of the world where horses are bred and/or our inability to determine the main vector for this Babesia species.…”