Vector competence of Aedes albopictus from Pine Bluff, Arkansas, for a St. Louis encephalitis virus strain isolated during the 1991 epidemic.
The vector competence of Aedes albopictus from Pine Bluff, AR, was assessed for a St. Louis encephalitis (SLE) virus strain isolated during the 1991 epidemic. Aedes albopictus were fed on hamsters with viremia levels of 10(4.6)-10(4.9) Vero cell plaque-forming units (PFU)/ml. At 7 and 15 days postbloodfeeding, transmission trials were conducted using individual suckling mice. Three of 313 Ae. albopictus were determined to be infected with SLE virus with titers of 10(6.3)-10(7.0) PFU/mosquito. At 15 days postbloodfeeding, one of 209 Ae. albopictus that 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 10(2.3) PFU/mosquito. Virus inoculated intracoelomically into Ae. albopictus replicated and reached mean titers above 10(6.0) PFU/mosquito on day 6. The combination of low susceptibility to infection and a mammalophilic bloodfeeding pattern suggests that Ae. albopictus is unlikely to play a significant role in SLE transmission.
Savage
H M
HM
Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
Smith
G C
GC
Mitchell
C J
CJ
McLean
R G
RG
Meisch
M V
MV
D000330:Aedes / Q000821:virology*; D000818:Animals; D001131:Arkansas / Q000453:epidemiology; D001717:Birds / Q000821:virology; D002645:Chickens / Q000821:virology; D006224:Cricetinae; D004196:Disease Outbreaks; D004665:Encephalitis Virus, St. Louis / Q000302:isolation & purification*; D004674:Encephalitis, St. Louis / Q000453:epidemiology / Q000635:transmission*; D005260:Female; D006801:Humans; D007303:Insect Vectors; D007814:Larva / Q000821:virology; D051379:Mice