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The pnncipa1 vectors
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biology and control methods
HI
Vectorcontrol
Fleas
fleas are blood-feeding (haematophagic) insects with a close relationship with their
host. Their developmental stages all occur on land.
The flea is usually a specific parasite but it is capable of changing its host (wild or
domestic rodent, man, etc.) in certain arcumstances.
Biology
The development cycle lasts about one month. The eggs are laid in dusty places in
houses or in rodents nests.
The larvae are found in darkplaces (negative photo-trohism).
In the adult stages both sexes are blood feeders.
Contairunation of the host may take place through a bite (plague) or excreta (typhus),
so dust may be highly contaminating.
Control methods
Control is essentially by chemical methods, even if cleaning dwellings and burning
dust gets rid of eggs and larvae.
It is essential to deternth-ie the sensitivity to any given insecticide because of the
many problems of resistance.
Bedding and clothes are treated with an insecticide powder.
Disinfectant products (chlorine solution, 4% cresyl, etc.) are effective against eggs
and larvae.
In the case of a risk of epidemic (plague) it is essential to destroy the population of
fleas without harming the host species (e.g. rat) because of the risk of human
infestation would be increased.
Control is done by putting insecticide powder on the rodent’s trails or in their nests.
Permethrin (0.5%), propoxur (1%) or any other effective insecticide is used.
(Organochiorines are generally ineffective.). The powder is laid down in lines 50cm
long and 3mm wide near to a non-poisonous bait, to attract the maximum number of
rodents.
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