b. There is a group of rodenticides called anticoagulants that are effective
against rodents. warfarin, pival, fumarin, and pindone are names of anticoagulant
chemicals used commonly to destroy rodent populations. The chemicals cause internal
hemorrhaging and prevent the blood from clotting. The rodent will simply bleed to
death. The anticoagulant types are quite good in that rodents do not develop bait
shyness. However, the rodent must consume this type of poison each day for several
days before it is effective. Killing will be evident usually between 5 and 10 days after
initial consumption. These chemicals are odorless and tasteless. Accidental ingestion
by humans is normally not fatal.
c. Red squill and zinc phosphide are two rodenticides that initiate emesis
(vomiting). Since rats are not capable of vomiting, these two chemicals will cause the
rats to go into convulsions caused by their inability to regurgitate the toxic material. Red
squill will ultimately cause death by heart paralysis, whereas zinc phosphide will cause
severe liver damage, thus killing the rodent. Zinc phosphide has a garlic odor which
attracts rats and is extremely toxic for short periods following ingestion.
d. Strychnine, which has a bitter taste and must be disguised, is a rat poison
used occasionally. Once rats eat a sufficient amount, hyperstimulation of the central
nervous system (CNS) will cause convulsions and a rapid death. Strychnine is also
harmful to humans if ingested.
e. Arsenic trioxide is a very effective poison that can be used in solution form,
dust, or as a bait poison against rats. It causes the blood vessels to relax and dilate
producing shock. Death is therefore by exhaustion; the heart cannot pump hard enough
to circulate the blood. Arsenic trioxide is also toxic to humans. Only trained personnel
should apply this rodenticide.
f. Sodium monofluoracetate, commonly known as "1080," is a rodenticide that is
very toxic to rats and humans; therefore, special permission is needed for its use and
then only by trained personnel. A significant rodent problem must occur before the use
of "1080" is allowed. It is used in a water solution and causes CNS hyperstimulation
thereby ultimately leading to cardiac arrest due to the inability of the heart to keep up
with the stimulation by the nervous system.
g. Alphanaphthylthiourea (ANTU) is another rodenticide used occasionally. It is
used predominantly in cases where the rodent problem is due to a population of Norway
rats. It is very toxic to Norway rats due to their physiology and only slightly toxic to roof
rats. The reason for this is not well known. It causes lung dropsy, a fluid buildup in the
lungs. A disadvantage to ANTU is that some rats will develop immunity to it. It seems
to be non-toxic to humans if only small amounts are ingested.