Tick modulation of host immunity: an important factor in pathogen transmission

Wikel, Stephen K.

doi:10.1016/s0020-7519(99)00042-9

Cited by 234 publications

(209 citation statements)

References 47 publications

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“…This review has focussed on mosquitoes and has thus ignored ticks as vectors that attach to a host for relatively long periods and for which there are substantial data demonstrating immune suppression (Gillespie et al 2000, Nuttall and Labuda 2004, Ribeiro 1989a, Wikel 1999. Despite the rapid feeding of mosquitoes, mosquito saliva clearly has immunomodulatory activity, and mounting data demonstrate that, as a consequence of this activity, mosquito-borne pathogens may be delivered to the vertebrate in an environment that is compromised in its ability to respond to and contain infection.…”

Section: Resultsmentioning

confidence: 99%

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Schneider

Higgs

2008

Transactions of the Royal Society of Tropical Medicine and Hygi

221

189

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SUMMARYArthropod-borne viruses have emerged as a major human health concern. Viruses transmitted by mosquitoes are the cause of the most serious and widespread arbovirus diseases worldwide and are ubiquitous in both feral and urban settings. Arboviruses, including dengue and West Nile virus are injected into vertebrates within mosquito saliva during mosquito feeding. Mosquito saliva contains anti-haemostatic, anti-inflammatory and immunomodulatory molecules that facilitate the acquisition of a blood-meal. Collectively, studies investigating the effects of mosquito saliva on the vertebrate immune response suggest that at high concentrations salivary proteins are immmunosuppressive, whereas lower concentrations modulate the immune response; specifically, T H 1 and antiviral cytokines are down-regulated, while T H 2 cytokines are unaffected or amplified. As a consequence, mosquito saliva can impair the anti-viral immune response thus affecting viral infectiousness and host survival. Mounting evidence suggests that this is a mechanism whereby arbovirus pathogenicity is enhanced. In a range of disease models, including various hosts, mosquito species, and arthropodborne viruses, mosquito saliva and/or feeding is associated with a potentiation of virus infection. Compared to arbovirus infection initiated in absence of the mosquito or its saliva, infection including mosquito saliva leads to an increase in virus transmission, host susceptibility, viraemia, disease progression, and mortality.Keywords arthropod-borne virus; mosquito saliva; immunomodulation; disease enhancement Most arthropod-borne (arbo)viruses of public health significance are mosquito-borne, and thus transmitted to vertebrates via the feeding of an infected mosquito. For a mosquito to

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Section: Resultsmentioning

confidence: 99%

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Schneider

Higgs

2008

Transactions of the Royal Society of Tropical Medicine and Hygi

221

189

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“…When infected ticks begin to feed, B. burgdorferi begins production of Erp proteins , but BbCRASP-1 or -2 remain largely undetectable during this time Bykowski et al, 2007, and our unpublished results). Ingested host complement is ineffective inside the tick midgut, presumably due to components of tick saliva that block complement activation (Ribeiro, 1987;Lawrie et al, 1999;Wikel, 1999;Valenzuela et al, 2000;Rathinavelu et al, 2003;Schroeder et al, 2007).…”

Section: Tick Nymphs and The Process Of Transmissionmentioning

confidence: 99%

Borrelia burgdorferi complement regulator-acquiring surface proteins (BbCRASPs): Expression patterns during the mammal–tick infection cycle

Bykowski

Woodman

Cooley

et al. 2008

International Journal of Medical Microbiology

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Host complement is widely distributed throughout mammalian body fluids and can be activated immediately as part of the first line of defense against invading pathogens. The agent of Lyme disease, Borrelia burgdorferi sensu lato (s.l.), is naturally resistant to that innate immune defense system of its hosts. One resistance mechanism appears to involve binding fluid-phase regulators of complement to distinct borrelial outer surface molecules known as CRASPs (complement regulator acquiring surface proteins). Using sensitive molecular biology techniques, expression patterns of all three classes of genes encoding the CRASPs of B. burgdorferi sensu stricto (BbCRASPs) have been analyzed throughout the natural tick-mammal infection cycle. Each class shows a different expression profile in vivo and the results are summarized herein. Studies on the expression of B. burgdorferi genes using animal models of infection have advanced our knowledge on the ability of the causative agent to circumvent innate immune defenses, the contributions of CRASPs to spirochete infectivity, and the pathogenesis of Lyme disease.

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“…Ticks also have highly developed and diverse mechanisms to suppress both the innate and acquired immune responses of hosts on which they commonly feed (Soneshine, 1993;Wikel, 1999). For example, the black-legged tick, Ixodes dammini can feed very successfully on its preferred host, the white footed mouse, Peromyscus leucopus, due to its ability to evade and suppress the host immune response (Ribeiro, 1989 and references therein).…”

Section: Observed Thatmentioning

confidence: 99%

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

Harrison¹,

Robb²,

Bennett³

et al. 2012

Veterinary Parasitology

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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.

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Tick modulation of host immunity: an important factor in pathogen transmission

Cited by 234 publications

References 47 publications

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Borrelia burgdorferi complement regulator-acquiring surface proteins (BbCRASPs): Expression patterns during the mammal–tick infection cycle

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

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