Biodegradable Pesticides in Public Health EntQmology
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indiscriminately by air, 97% of the insecticide would be applied to land where
none was required.
8.5.3. Aedes aegypti
Within the context of source reduction, Ae. aegypti is an enigma. It is the
sole vector of dengue viruses in the Western Hemisphere and in much of the
Eastern Hemisphere, yet dengue epidemics continue to surge and resurge in both
hemispheres. In most places, Ae. aegypti is a domestic or peridomestic species,
with its breeding restricted to small containers of water. If there is an important
vector mosquito that should be amenable to control by simplistic measures, it
is Ae. aegypti. It cannot breed if such water containers as old tires and tins are
eliminated and essential water storage containers made mosquito-proof (Reuben
and Panicker, 1975, and many others). Yet, as stated by Reeves (1972), "we
seem to be in the unenviable position that we have a wealth of research knowledge
that continues to build while we have little or no immediate hope of preventing
dengue epidemics."
Wattal (1971) states that there is no concerted effort to control Ae. aegypti
in India, although the species could be controlled by mosquito-proof storage of
water and elimination of the breeding foci. In the U.S. apparently only one
organized mosquito abatement district, Dade County, Florida, regularly attempts
Ae. aegypti control. This district conducted 59,900 premise inspections in 1972
(NAS, 1976). There was an eradication effort in the United States during the
decade of the sixties, but Ae. aegypti persists in cities in the southern part of the
country, and the U.S. remains vulnerable, therefore, to the reappearance of
dengue.
8.5.4. Aedes triseriatus
The vector species that I work on, Ae. triseriatus, may be second only to
Ae. aegypti as a species amenable to simplistic measures of control. Ae. triseriatus is the vector of La Crosse (LAC) virus, one of the California encephalitis
group. A hundred cases, more or less, are reported annually from the eastern
two-thirds of the United States. The virus is transmitted transovarially (Watts
et at., 1973) and overwinters in the diapausing eggs of the mosquito (Watts et
at., 1974). Chipmunks and tree squirrels are the vertebrate hosts involved in
summer amplification of the virus (Moulton and Thompson, 1971).
In the last few years it has become our goal to model the transmission
dynamics of the LAC system in order, hopefully, to predict the conditions under
which transmission would be interrupted. As is usually the case, the deeper a
problem is probed, the more complicated it gets. So far, about 40 parameters
205
indiscriminately by air, 97% of the insecticide would be applied to land where
none was required.
8.5.3. Aedes aegypti
Within the context of source reduction, Ae. aegypti is an enigma. It is the
sole vector of dengue viruses in the Western Hemisphere and in much of the
Eastern Hemisphere, yet dengue epidemics continue to surge and resurge in both
hemispheres. In most places, Ae. aegypti is a domestic or peridomestic species,
with its breeding restricted to small containers of water. If there is an important
vector mosquito that should be amenable to control by simplistic measures, it
is Ae. aegypti. It cannot breed if such water containers as old tires and tins are
eliminated and essential water storage containers made mosquito-proof (Reuben
and Panicker, 1975, and many others). Yet, as stated by Reeves (1972), "we
seem to be in the unenviable position that we have a wealth of research knowledge
that continues to build while we have little or no immediate hope of preventing
dengue epidemics."
Wattal (1971) states that there is no concerted effort to control Ae. aegypti
in India, although the species could be controlled by mosquito-proof storage of
water and elimination of the breeding foci. In the U.S. apparently only one
organized mosquito abatement district, Dade County, Florida, regularly attempts
Ae. aegypti control. This district conducted 59,900 premise inspections in 1972
(NAS, 1976). There was an eradication effort in the United States during the
decade of the sixties, but Ae. aegypti persists in cities in the southern part of the
country, and the U.S. remains vulnerable, therefore, to the reappearance of
dengue.
8.5.4. Aedes triseriatus
The vector species that I work on, Ae. triseriatus, may be second only to
Ae. aegypti as a species amenable to simplistic measures of control. Ae. triseriatus is the vector of La Crosse (LAC) virus, one of the California encephalitis
group. A hundred cases, more or less, are reported annually from the eastern
two-thirds of the United States. The virus is transmitted transovarially (Watts
et at., 1973) and overwinters in the diapausing eggs of the mosquito (Watts et
at., 1974). Chipmunks and tree squirrels are the vertebrate hosts involved in
summer amplification of the virus (Moulton and Thompson, 1971).
In the last few years it has become our goal to model the transmission
dynamics of the LAC system in order, hopefully, to predict the conditions under
which transmission would be interrupted. As is usually the case, the deeper a
problem is probed, the more complicated it gets. So far, about 40 parameters