Fenitrothion


Fenitrothion is a phosphorothioate insecticide that is inexpensive and widely used worldwide. Trade names include Sumithion, a 94.2% solution of fenitrothion.

Health effects

Fenitrothion at sublethal doses affected the motor movement of marsupials, and at acute dose levels it reduced the energy of birds.
In chronic dose tests, unexpectedly only the lowest concentration of fenitrothion depressed the growth of an algae, though all of the chronic dose levels used were toxic in other ways to the algae.
Just half of fenitrothion's minimally effective dose altered the thyroid structure of a freshwater murrel.
Cases of non-specific encephalopathy and fatty visceral changes in children living in the vicinity of fenitrothion-spraying operations invoked the research described latterly in Science, and originally in The Lancet:
Further study showed that the illness was caused not by fenitrothion itself, but combinations which included the surfactants and the solvent clearly showed that pretreatment with these chemicals markedly increased the viral lethality in the test mice.

Resistance

In an unusual demonstration of resistance to pesticides, 8% of insects in farm fields were found to carry a symbiotic gut microbe that can metabolize and detoxify fenitrothion; after in-vitro tests showed that the microbe significantly increased the survival of fenitrothion-treated insects.