Epidemiologic Notes and Reports
Update: Aedes albopictus Infestation - United States
In August 1985, an infestation of Aedes albopictus ("Asian Tiger
Mosquito"), an exotic mosquito known to transmit epidemic dengue
fever in its native Asia, was discovered in Harris County, Texas.
Aedes albopictus has been shown in the laboratory to be capable
of efficientiy transmitting dengue and several other viruses
(including California [LaCrosse] encephalitis virus) that can
infect humans and are indigenous to the United States. In the
spring of 1986, efforts were begun to determine the distribution
of this mosquito vector in the United States. The most recent
survey for Ae albopictus breeding was conducted September 15-29
in Ohio, Indiana, Illinois, Missouri, Kentucky, and Arkansas.
Sites inspected were the business premises of tire dealers and
re-treaders, because the mosquito commonly breeds in standing
water found in tires stored outdoors on their sides. As.
albopictus larvae were found in at least one location in two of
10 counties surveyed in Illinois, two of 10 in Indiana, three of
11 in Missouri, and one of seven in Arkansas; none were found in
the Kentucky survey. In early September, a single positive site
had bien discovered by the Ohio Department of Health in Darke
County; no further breeding was found during surveys in five
other Ohio counties. Oviposition trap surveillance also has
provided evidence for an infestation in San Antonio, Texas.
Figure 1 shows the present distribution of As.
albopictus-positive counties.
To determine the mode of Introduction and to characterize the
risk of further introduction, CDC has conducted inspections of
used auto and truck tires entering United States ports from Asia,
the source of several million used tires each year. For example,
in 1 985, a total of 3.2 million used tires were imported, of
which 2.8 million came from Asian countries with indigenous Ae
albopictus populations, including 890,000 from Japan.
On October 6-7, 1986, inspectors checked 2,013 tires in nine
cargo containers originating in Japan and off-loaded in Seattle,
Washington; As. albopictus larvae were found in 11 tires in two
of the cargo containers. The two positive containers had a higher
proportion of tires (91%) holding water than did the negative
containers (17%). Both positive containers were shippad by the
same exporter in Japan. The positive containers were fumigated
with methyl bromide to kill larvae and ova. Although tire
shipments originating in Japan have been inspected since June,
the October shipment was the first one found to be infested.
Reported by E Roberts, Barberton Health Dept, D Somers, Cuyahoga
County Health Dept, K Mizer Stark County Health Dept, M Parsons,
R Berry, E Perterson, Ohio State Health Dept G Creig, W Hewlay, K
Rai, P Grimstad, Notre Dome University, C Dulla; S Brewer, J
Erwin, Marion County Health Dept, D Hervey, Clark County Health
Dept, C Mayfeld, M Galbraith, Bartholomew County Health Dept, M
Sinsko, PhD, B Foster, E McDonald, V Dunn, Indiana State Board of
Health; J Nielsen Louisville-Jefferson County Health Dept, G
Moorer, Lexington-Fayette County Health Dept, C Gayle, Kentucky
Dept of Agricurture; H Meyer City of St. Louis Health Divsion, W
Willey, W Kottkamp, St. Louis County Health Dept, H Bengsch, J
Boles, Springfield-Green County Health Dept, J Hounschell, City
of Joplin Dept of Health and Welfare,, C Lansford, Jefferson City
Dept of Planning end Code Enforcement, C Sanders, City of
Columbia-Boone County Dept of Hearth, A Thomas, Kansas City
Health Dept, F Unnewehr, R Tanner R field, R Larkam, Missouri
State Health Dept; H Dominic, L Heramis, PhD, Illinois Dept of
Public Health; E Swearingen Jr., Ft. Smith-Sebastian County Dept
of Public Health; D Hermon, Area 1 Headquarters, Akansas State
Health Dept; M Meisch, PhD D Bessi,; A Weathersbee, M Riggs, Dept
of Entomology University of Arkanses, D Purifoy, Miller County
Hearth Dept, M Townsend, Jefferson County Health Unit, H Spatz,
Faulkner County Health Unit, D Edwards, T Reid, North Little Rock
Health Dept, W Tear, R Neill, K Free; Arkansas State Hearth Dept;
Div of Vector-Borne Viral Diseases, Center for Infectious
Diseases, CDC.
Editorial Note
Editorial Note: The recent surveys described above confirm the
presence of Ae. al,lcoictus in northern areas of the
Ohio-Mississippi Valley, an area in which California (LaCrosse)
encephalitiss is known to be endemic. Because laboratory studies
have shown that Ae. albopictus is capable of entering diapause
(1), it is expected that these populations will sucessfully
overwinter and resume breeding activity in the spring. In the
summer of 1987, investigations should be conducted to determine
the role of Ae. albopictus in transmission of California-group
viruses - especially LaCrosse encephalitis - in the Central
United States.
The evidence suggests that the Ae. albopictus infestation of
the northern United States has occurred relatively recently,
since only seven (13%) of 53 counties sampled were infested in
Ohio, Indiana, Illinois, Kentucky, Missouri, and Wisconsin,
compared with 31 (89%) of 35 counties sampled in the area of the
the United States already known to be infested by this mosquito
(Texas, Louisiana, and Mississippi). Efforts to control/prevent
the spread of Ae. albopictus in the northern states will become
an even greater concern as mosquito breeding resumes next spring.
The finding of infested used tires in Washington State
indicates a need for further evaluation of the hypothesis that
importation of tires from Asia represents a possible source of
the original infestation in the United States. CDC is currently
reviewing options for preventing further introduction of
Ae. albopictus.
Reference
Craig GB. University of Notre Dame. Personnal communication.
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