Powassan (POW) virus, the cause of human encephalitis in the northeastern U.S. and Canada, is transmitted by tick bite. Since the geographic and host distribution patterns of Ixodes dammini Spielman, et al, 1979 and POW virus overlap, the potential of this tick species to transmit POW virus was explored. Transmission experiments were conducted with hamsters and rabbits which fed immature and adult ticks, respectively, from a POW-free colony. Oral infection rates in larvae and nymphs fed on POW-infected hamsters were 10% and 40%, respectively; in females fed on POW-infected rabbits, 57%. Transstadial transmission rates for nymphs exposed to POW virus as larvae, adults exposed as larvae, and adults exposed as nymphs, were 9.5%, 10% and 54%, respectively. Evidence of transovarial transmission was acquired when 2 clean hamsters feeding F$ sb2$ larvae and nymphs originally exposed to virus in the F$ sb1$ nymphal stage seroconverted to POW virus with hemagglutination inhibition titers of 80 and 5120, respectively, on week 4 post-tick-drop-off. The transovarial transmission rate was 16.6%. All developmental stages were able to transmit POW virus orally to clean hosts regardless of when the ticks were originally exposed to virus. / These results indicate that I. dammini is a competent vector of POW virus under experimental conditions. Field studies are necessary to determine if the same holds true under natural conditions.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.28563 |
| Date | January 1994 |
| Creators | Costero, Adriana |
| Contributors | Hill, Stewart B. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001443068, proquestno: NN00151, Theses scanned by UMI/ProQuest. |
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