Why the results of
Dengue mosquito surveillance are not very accurate?
Assumptions: All
detrains are considered as containers.
All
mosquitoes larvae are assumed as Aedes
mosquitoes.
Aedes surveillance are carried
out during dry season, following mistakes/ errors are taken place. Mosquito eggs are able to inactive for long
time period till favorable conditions are returned. So there is high probability
to results to be inaccurate. Aedes misquotes are container breeders.
They use clean and clear water for their eggs lying. They also cannot be found in moving water.
But some of detrains in the premises contain moving water. Therefore larvae
found in the moving water cannot be Aedes
larvae. Water containing organic matter from sinks are directed into
detrains. Since Aedes larvae prefer
clean and clear water, larvae found in organically polluted water cannot be Aedes larvae. It is difficult to examine all containers in
the premises. It is impossible to reach gutters and discard tires on the roof.
Therefore results cannot be very accurate. The risk may be higher than the
observed value. Due to the low risk, control measures may be not applied or not
considered.
If
the
Why pupae surveys
are rarely done?
Because
it is very difficult to identify pupae till the species level. So it takes more time and less effective.
What are the
disadvantages of adult surveys?
Most
of adult survey use human baits. But it is not convenient ethically because
parasite can be transmitted from mosquito vector into human body. So people
with low immunity, there is high probability to be suffered from diseases. It
is a time consuming method. Although they active during day time, It is
difficult to catch because they active only 7-10 in the morning and 3-5 in the
afternoon. Adults can be collected from their resting habitats such as shady
and shadow places.
What are the
control measures?
For
high risk areas, eggs, larvae, pupae and adults are killed. Mosquito breeding
is avoided or minimized. Waste should be disposed in a proper way. Water
accumulation in both natural and artificial containers should be minimized.
Insecticides should be applied to kill larvae and adults. Larvivorous fishes
such as Poecilia reticulata should be
introduced to reduce larvae. Chemical repellents such as citric oil and
chemical applied net should be used to disturb the contact between misquotes
and human.
Low
risk areas are clean and no breeding places are available for mosquito
breeding. For low risk area, no need to apply control measure. It is required
to maintain environment hygiene in order to prevent to be high risk area.
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