Differential feeding success of two paralysis-inducing ticks, Rhipicephalus warburtoni and Ixodes rubicundus on sympatric small mammal species, Elephantulus myurus and Micaelamys namaquensis

Abstract

Rodents are recognised as important hosts of ixodid ticks and as reservoirs of tick-borne pathogens across the world. Sympatric insectivores are inconspicuous and often overlooked as hosts of ticks and reservoirs of disease. Elephant shrews or sengis of the order Macroscelidea are small insectivores that often live in sympatry with rodents in South Africa.Sengis are invariably parasitised by large numbers of immature ticks while sympatric rodents are infested with very few. The reason for the difference in tick parasitism rates between these hosts is unknown. While a number of mechanisms are possible, we hypothesised that ticks would exhibit "true host specificity" and as such would only attach and feed successfully on their preferred host. To investigate this, we conducted feeding experiments using two economically important tick species, the brown paralysis tick, Rhipicephalus warburtoni and the Karoo paralysis tick, Ixodes rubicundus using two sympatric small mammal species as potential hosts, the eastern rock sengi, Elephantulus myurus and the Namaqua rock mouse, Micaelamys namaquensis. Ticks attached and fed readily on E.2 myurus but did not attach or feed successfully on M. namaquensis suggesting that these ticks exhibit true host specificity. We suggest that a kairomonal cue originating from the odour E. myurus stimulates attachment and feeding of these ticks and they possess immunosuppressive mechanisms specific to E. myurus, allowing them to feed on this host species but not on M.namaquensis. This study highlights the importance of small mammalian insectivores as hosts of ixodid tick species and their potential as reservoirs of tick-borne pathogens.

The Namaqua rock mouse (Micaelamys namaquensis) as a potential reservoir and host of arthropod vectors of diseases of medical and veterinary importance in South Africa

“…Consequently, most of these infestations can be considered accidental and M. namaquensis is unlikely to play a major role in maintaining these ticks or act as an important reservoir for any of the diseases they transmit. In fact, it has been shown that M. namaquensis is a poor host for Ixodes rubicundus (causing sheep paralysis) and R. warburtoni (carrying A. bovis and causing goat paralysis) and these tick species exhibit a preference for sympatrically occurring eastern rock sengis ( Elephantulus myurus ) as hosts [28–30, 58, 59]. In contrast, R. distinctus was the main tick species found on M. namaquensis at a high prevalence and abundance.…”

The more the merrier – experimental evidence for density-dependent feeding facilitation in the bird-specialised tick Ixodes arboricola

“…Aggregation of ticks (Davidar et al, 1989;Harrison et al, 2012;Moshaverinia et al, 2012;Heylen et al, 2013a) and many other parasites (Shaw and Dobson, 1995;Woolhouse et al, 1997;Wilson et al, 1998;Poulin, 2007;Calabrese et al, 2011) in nature primarily occurs due to heterogeneity in host exposure and susceptibility to parasitism (Wilson et al, 1998;Poulin, 2013). However, there may be adaptations that lead to aggregation and on which selection can operate.…”

“…Luttrell et al, 1996;Monks et al, 2006;Matthysen, 2008, 2011a;Pfäffle et al, 2009). Yet, in nature relatively few individual hosts harbour the majority of ixodid ticks (Davidar et al, 1989;Harrison et al, 2012;Moshaverinia et al, 2012;Heylen et al, 2013a).…”

Proteomics Approach to the Study of Cattle Tick Adaptation to White Tailed Deer

“…Ticks fed on cattle were probably ingesting more blood as reflected by higher tick weights (Table 1). Although ticks easily adapt to feeding on new host species [10], host factors such as odor and metabolites could increase blood ingestion in ticks fed on cattle when compared to ticks fed on WTD considering that these ticks were maintained in the laboratory by feeding on cattle [24–27]. Higher levels of host proteins involved in immunity such as Alpha-2-macroglobulin and Immunoglobulin-like proteins in ticks fed on cattle when compared to ticks fed on WTD probably reflected differences in host response to tick infestations [23].…”