Vector competence of Aedes albopictus from Pine Bluff, Arkansas, for a St. Louis encephalitis virus strain isolated during the 1991 epidemic
Savage, H.M.; Smith, G.C.; Mitchell, C.J.; McLean, R.G.; Meisch, M.V.
Journal of the American Mosquito Control Association 10(4): 501-506
1994
ISSN/ISBN: 8756-971X PMID: 7707054 Document Number: 423739
The vector competence of A. albopictus from Pine Bluff, Arkansas, USA, was assessed for a St. Louis encephalitis (SLE) virus strain isolated during the 1991 epidemic. A. albopictus were fed on hamsters with viraemia levels of 104.6-104.9 Vero cell plaque-forming units (PFU)/ml. At 7 and 15 days postbloodfeeding, transmission trials were conducted using individual suckling mice. 3 of 313 A. albopictus were determined to be infected with SLE virus with titres of 106.3-107.0 PFU/mosquito. At 15 days postbloodfeeding, 1 of 209 A. albopictus than refed transmitted virus resulting in a 15-day population transmission rate of 0.5%. The infection threshold (i.e. the amount of virus required to infect from 1 to 5% of mosquitoes) was determined to be approximately 102.3 PFU/mosquito. Virus inoculated intracoelomically into A. albopictus replicated and reached mean titres above 106.0 PFU/mosquito on day 6. The combination of low susceptibility to infection and a mammalophilic bloodfeeding pattern suggests that A. albopictus is unlikely to play a significant role in SLE transmission.