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

A Harrison, G N Robb, N C Bennett, I G Horak

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Rodents are recognised as important hosts of ixodid ticks and as reservoirs of tick-borne pathogens across the world. Sympatric insectivores are usually 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 occur in sympatry with rodents in southern 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 certain tick species exhibit "true host specificity" and as such would only attach and feed successfully on their preferred host or a very closely related host species. 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 and 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. 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 of E. myurus may stimulate the attachment and feeding of these ticks and that they further 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 potential hosts of ixodid tick species and hence their potential as reservoirs of tick-borne pathogens.
Original languageEnglish
Pages (from-to)346-354
Number of pages9
JournalVeterinary Parasitology
Volume188
Issue number3-4
DOIs
Publication statusPublished - 10 Sep 2012

Fingerprint

Tick Paralysis
Ixodes rubicundus
Rhipicephalus
Ixodes
Ticks
paralysis
small mammals
ticks
Mammals
insectivores
Macroscelidea
Rodentia
Host Specificity
rodents
host specificity
Disease Reservoirs
Shrews
Sympatry
Southern Africa
rocks

Keywords

  • toxic paralysis
  • host specificity
  • host choice
  • ixodes
  • rhipicephalus
  • insectivore
  • rodent

Cite this

Differential feeding success of two paralysis-inducing ticks, Rhipicephalus warburtoni and Ixodes rubicundus on sympatric small mammal species, Elephantulus myurus and Micaelamys namaquensis. / Harrison, A; Robb, G N; Bennett, N C; Horak, I G.

In: Veterinary Parasitology, Vol. 188, No. 3-4, 10.09.2012, p. 346-354.

Research output: Contribution to journalArticle

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AB - Rodents are recognised as important hosts of ixodid ticks and as reservoirs of tick-borne pathogens across the world. Sympatric insectivores are usually 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 occur in sympatry with rodents in southern 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 certain tick species exhibit "true host specificity" and as such would only attach and feed successfully on their preferred host or a very closely related host species. 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 and 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. 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 of E. myurus may stimulate the attachment and feeding of these ticks and that they further 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 potential hosts of ixodid tick species and hence their potential as reservoirs of tick-borne pathogens.

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