Many arthropods besides the mosquito are disease vectors for humans. Houseflies
carry disease microorganisms and parasitic worms. They spread diseases such as
typhoid fever, paratyphoid fever, bacillary and amebic dysentery, cholera, typhus,
anthrax, gastroenteritis, conjunctivitis, trachoma, and various viral diseases. Wood
ticks and dog ticks infected with ricksettsia carry Rocky Mountain Spotted fever, Q
fever, and typhus. They are also vectors for tuleremia caused by the bacterium
Pasteurella tularensis.
The list of pesticides suitable for these vector arthropods is long. The
nonpersistence of the organophosphorus and carbamate insecticides (1–12 weeks)
and neonicotinoids (days to years depending on exposure to light) has made these the
pesticides of choice in many instances. And yet, when dealing with a disease
problem, the use of more persistent insecticides has been justified. Recommendations for the use of specific agents can be found in various sources, but interested
persons should consult the USEPA registry [4] for current regulations regarding the
use of any of the pesticides since these are rapidly changing.
Some pesticides which were first registered years ago must be re-registered to
ensure that they meet today’s more stringent standards.
In mosquito control, carbaryl has been used extensively for control of the adult,
and malathion both for adult larvae in outdoors spraying. Dichlorvos (chlorinated
organophosphorus insecticide) and malathion have been widely used in outdoor
spraying for fly control.
5.3 Vertebrates
The rat is one of the most destructive vectors of disease and human parasites.
Because of growth and proliferation, rats annually cause millions of dollars of
damage to stored foods and materials in the United States alone.
Some of the diseases carried by the rat are bubonic plague, caused by the
bacterium Pasteurella pestis, transmitted to humans by fleas, and leptospirosis,
which is transmitted by direct bite. Leptospiral jaundice also is transmitted to
humans and, more frequently, to the domestic dog.
Rat poisons are toxic against other rodents as well, such as mice, rabbits, and
squirrels. Rats migrate in the absence of food, water, or shelter; they are also
confined to a certain population size by existing conditions. It is obvious then that
a rat-poisoning program without accompanying cleanup procedures is a strictly
temporary relief, since survivors or newcomers will eventually multiply to again
fill the vacant capacity of the previously infested environment.
The placing of poisoned baits is commonly employed in rat-poisoning programs.
Care must be taken that the poison selected is rapidly detoxified within the rat or that
the poisoned animals are immediately removed to avoid transmission to other
animals.
Anticoagulants such as Warfarin were the preferred rat poisons for most baiting
purposes, but continuous feedings were required for 3–10 days, causing high labor
10 Environmental Control of Pests and Vectors
399
carry disease microorganisms and parasitic worms. They spread diseases such as
typhoid fever, paratyphoid fever, bacillary and amebic dysentery, cholera, typhus,
anthrax, gastroenteritis, conjunctivitis, trachoma, and various viral diseases. Wood
ticks and dog ticks infected with ricksettsia carry Rocky Mountain Spotted fever, Q
fever, and typhus. They are also vectors for tuleremia caused by the bacterium
Pasteurella tularensis.
The list of pesticides suitable for these vector arthropods is long. The
nonpersistence of the organophosphorus and carbamate insecticides (1–12 weeks)
and neonicotinoids (days to years depending on exposure to light) has made these the
pesticides of choice in many instances. And yet, when dealing with a disease
problem, the use of more persistent insecticides has been justified. Recommendations for the use of specific agents can be found in various sources, but interested
persons should consult the USEPA registry [4] for current regulations regarding the
use of any of the pesticides since these are rapidly changing.
Some pesticides which were first registered years ago must be re-registered to
ensure that they meet today’s more stringent standards.
In mosquito control, carbaryl has been used extensively for control of the adult,
and malathion both for adult larvae in outdoors spraying. Dichlorvos (chlorinated
organophosphorus insecticide) and malathion have been widely used in outdoor
spraying for fly control.
5.3 Vertebrates
The rat is one of the most destructive vectors of disease and human parasites.
Because of growth and proliferation, rats annually cause millions of dollars of
damage to stored foods and materials in the United States alone.
Some of the diseases carried by the rat are bubonic plague, caused by the
bacterium Pasteurella pestis, transmitted to humans by fleas, and leptospirosis,
which is transmitted by direct bite. Leptospiral jaundice also is transmitted to
humans and, more frequently, to the domestic dog.
Rat poisons are toxic against other rodents as well, such as mice, rabbits, and
squirrels. Rats migrate in the absence of food, water, or shelter; they are also
confined to a certain population size by existing conditions. It is obvious then that
a rat-poisoning program without accompanying cleanup procedures is a strictly
temporary relief, since survivors or newcomers will eventually multiply to again
fill the vacant capacity of the previously infested environment.
The placing of poisoned baits is commonly employed in rat-poisoning programs.
Care must be taken that the poison selected is rapidly detoxified within the rat or that
the poisoned animals are immediately removed to avoid transmission to other
animals.
Anticoagulants such as Warfarin were the preferred rat poisons for most baiting
purposes, but continuous feedings were required for 3–10 days, causing high labor
10 Environmental Control of Pests and Vectors
399