Commensel Rodents.pptx.pdf

1. Presented by: Jack Launius

2. Commensal Rodents
You'll learn the types of rodents, specific biology, health concerns, insect
disease vectors and other secondary pests.
Rodents are a diverse type of animal and many types of rodents are considered
pest species. The most particular of these rodent species are rats and mice.
While gophers and other non-commensal rodents can be invasive and of large
concern, some of the most problematic structural pests include rats and mice.
Several species of rats and mice are considered commensal pests because of
their dependence on humans.

3. Commensal Rodents
•Between rats and mice, rats are the larger of the two species.
•Obvious differences can be noted between them with regards to their
appearance as well. A rat pup can be about the same size as an adult
mouse, making identification difficult, but mice have much smaller
ears in relation to their heads.
•This could help to identify a caught rodent, but if there is still doubt
identification can be made by looking at the tail.
•Rats have a tail that is longer than their bodies, especially in the
young, but mice have a tail that is almost always equal in length to
their bodies.

5. Part 1. Commensal Rodents
•Rodents are a diverse type of animal and many types of rodents are
considered pest species. The most particular of these rodent species are
rats and mice.
•While gophers and other non-commensal rodents can be invasive and of
large concern, some of the most problematic structural pests include
rats and mice. Several species of rats and mice are considered
commensal pests because of their dependence on humans.

6. Commensal Rodents
Between rats and mice, rats are the larger of the two species. Obvious differences
can be noted between them with regards to their appearance as well.
A rat pup can be about the same size as an adult mouse, making identification
difficult, but mice have much smaller ears in relation to their heads.
This could help to identify a caught rodent, but if there is still doubt identification
can be made by looking at the tail.
Rats have a tail that is longer than their bodies, especially in the young, but mice
have a tail that is almost always equal in length to their bodies.

7. Commensal
Rodents
The more common species of mouse
encountered in homes is the house mouse
(Mus domestics). While mice usually don’t
stray more than 10 – 30 feet from the nest
on average, they can in some cases go as far
as 50 feet for food.
50 feet is not however typical, and when
mice are entering a structure it can usually
be traced back with the entry point very
close to the areas of activity.

8. Commensal Rodents
Mice living within a structure are more complicated however,
and careful distinctions should be made as to the current level,
and type of activity. Mice, unlike rats, do not require a water
source.
Mice receive water from the food they eat and are sustained
even from the driest foods. This is why liquid rodent baits for
mice are ill-advised solutions.

9. Commensal Rodents
Rats on the other hand require water constantly and liquid baits can be
a beneficial tool for their control. Interior treatments for the house
mouse should focus on trapping the majority of the population,
removing food sources, and excluding areas of entry into the
structure.
Outside, smaller mouse specific bait stations can be used and
harborage areas corrected. This means that bushy plants close to the
structure and more specifically close to entry points should be trimmed
or removed to prevent nesting close to the structure.

10. Commensal Rodents
House mice have 4-7 pups per litter on average according to studies. This number is
significant because mice are able to mate in as little as 5 weeks and up to 8 times per
year.
They reproduce quickly and if a large majority of the population is living and nesting
within a structure fumigation may be required to control them, or a relatively large
number of traps combined with a diligent integrated pest management plan.
In the case of mice living inside of a structure the most reasonable and least intrusive
method for control is trapping. Properly placed traps should be able to catch and
eliminate the entire population.
Only in rare cases is fumigation ever required. Fumigations should be reserved for
those rare cases that it is appropriate, and necessary.

11. Commensal Rodents
Norway rats are relatively large blunt nosed rodents that most often make
burrows outside, with food and harborage close by. Roof rats on the other
hand are slightly smaller, forage much larger areas, and have pointed
noses. The forage area for Norway rats is roughly 100 – 300 feet from their
nest with roof rats foraging up to 450 ft.
Roof Rat

12. Commensal Rodents
Norway rats are often seen or found closer to the ground where they
make their burrows but roof rats can be seen in all areas from the
ground to the roofline, and in trees.
Bait station and trap placement may differ such as is the case when
bait stations are placed close to Norway rat burrows. Stations are
most effective however when placed between food and harborage.
Therefore, placement should be made only after a thorough
assessment of the property is made.

13. Commensal
Rodents
While bait stations can be effective alone
for Norway rats, baiting the individual
burrows is sometimes helpful.
The burrows are essentially where the rats
live, and filling their burrows with tracking
powder eliminates them at their source.
The product works very simplistically. As
rats lick the product off of themselves, they
ingest it, and it contains a poison. They
can’t avoid it because it’s in their burrow.

14. Commensal
Rodents
Norway rats have much larger litters than roof rats
and house mice.
Their litters are on average 8-12 pups, but house
mice average 4-7 and roof rats average 4-8.
Rats in general have 4-7 litters per year for roof rats
and 4-8 litters per year for Norway rats.
Treating the burrows helps with the younger rats
since they tend to stay with the mother until they
reach maturity.

15. 2. Rodent
specific
biology
All 3 species of commensal rodents are
thigmotactic.
Thigmotaxis is when an organism uses
touch to identify its path or direction.
As a result of rodents being
thigmotactic they can be found moving
along vertical surfaces such as walls.

16. 2. Rodent specific biology
Traps should therefore most often be placed along these vertical surfaces
inside, and bait stations can be placed along exterior walls and fences for
enhanced levels of control.
This small but significant bit of information can be used to identify failed
control methods. In many cases traps are used unsuccessfully because they
are placed in the open center of an area.
In many cases traps are used unsuccessfully because they are placed in the
open center of an area.

17. 2. Rodent
specific
biology
Rats rarely forage away from the areas near walls and
other areas that provide the touch stimulus.
When they do forage away from walls and other
areas where they can touch, it is because they have
developed a familiarity with the area.
In this case however setting traps in an area away
from vertical surfaces such as the center of a room is
still ill-advised.
Those traps placed openly in the center of an open
area are less likely to catch anything.

18. 2. Rodent
specific
biology
Rats and mice can squeeze through
seemingly unbelievable spaces.
Many believe this is the result of bendable
bones, cartilage in place of bones, or
issues to do with the bone structure of
their bodies, but rats actually have normal
bones that don't flex or bend.

19. 2. Rodent specific biology
•Rats and mice instead use their whiskers to identify which holes their body
can fit through.
•In general, if their heads fit, their bodies fit. Rats can generally get through
a hole as small as ½ inch, and mice holes as small as ¼ inch.
• If rats and mice can fit their nose into a hole and gnaw or chew at that
hole they will do so until their entire head fits.
•With their entire head through and whiskers free they know that the rest of
their body can fit. In rare cases rats can get stuck however. This is the
result of a larger than normal body that occurs as a result of over eating.

20. 2. Rodent
specific
biology
Rats also chew regularly on
items of little consequence
to them such as electrical
wires, and prefer food that is
crunchy such as dog and cat
food.
This creates an obvious
problem for those
customers with pets, but
likewise an obvious IPM
minded control solution.

21. 2. Rodent specific
biology
Customers should control the access that rodents may have
to any kind of animal feed.
This is often accomplished by emptying and putting away
animal feeding bowls, and storing the inventory in rat proof
containers.
Dog and cat food usually comes in paper bags that rodents
can easily eat their way into, therefore storage inside of a
metal cabinet or transferring the food to a metal trash can
with a lid is highly recommended.
This Photo by Unknown author is licensed under CC BY-SA-NC.
This Photo by Unknown author is licensed under CC BY-SA-NC.

22. 2. Rodent specific
biology
Rodents are forced to sharpen and
fine down their teeth as their teeth
continue to grow throughout their life
cycle.
This makes crunchy items such as dog
and cat food highly desirable to
rodents. This small piece of pertinent
information provides a level of insight
that can add tremendously to any
rodent control plan.
This Photo by Unknown author is licensed under CC BY-SA-NC.

23. 2. Rodent specific
biology
Rodent droppings are a key sign of infestation and while they may
be confused with other types of pest droppings, they can also be
easily distinguished from other types if careful attention is given.
Norway rats have the largest droppings of the three types of
commensal rodents. The individual droppings can be as long as ¾
of in.
The key factor is shape is their blunt ends.

24. 2. Rodent
specific
biology
While cockroach droppings may be a similar
shape (not exactly however) they are not as
large.
Roof rats on the other hand have droppings that
are pointed on the ends, and can often have a
slight curve giving them a sausage shape.
They are not as large as Norway rat droppings,
but can often be found scattered, unlike the
Norway rat droppings that are found in groups,
or clusters.

25. 2. Rodent specific biology
The droppings of a house mouse are about the size of a grain of rice,
and pointed at both ends.
Mouse droppings may appear to be long in regards to their shape as
compared to the rat droppings.
As rodent droppings get older the color changes, and in many cases
the older droppings will appear to be greyish.
When fresh however, they are dark and soft. As time passes they
change color as they dry out, and also lose the initial glisten of
moisture.
The lighter the color, the less fresh they are, and the darker the color,
the fresher they are.

26. Part 3. Health
Concerns
•Rodents also pose severe health
concerns. The first of which involves
allergens. Some studies have shown that
the urine of mice can cause asthma and
other similar conditions.
•Similar theories exist in regards to rodent
droppings, and hairs.
•No specific study is cited here however in
regards to hairs and droppings.

27. Health Concerns
•Many people however do have allergies to different types of
animal hairs including dog, cat, rabbit, and others.
•It seems reasonable to assume then that allergies to hairs found
on rodents, and left behind may cause some type of allergy in
some people.
•Cleaning, and sanitation is considered the most viable solution
in cases of believed allergen presence in addition to removing
the rodent problem.

28. Health Concerns
Rodents can also carry many types of diseases, bacteria, and viruses. The first of which is
Hantavirus.
There are several hantavirus strains, but the one of most importance is referred to as HPS,
hantavirus pulmonary syndrome.
HPS has been implicated in several high profile instances, such as a string of cases in 1993 near
the four corners states where it was referred to as the "sin nombre" virus, or in 2012 where a
campsite at Yosemite National Park saw several campers become ill as a result of the virus.

29. Health
Concerns
Before the incident in 1993 hantavirus
hadn't been found in the United States, but
upon further review it was determined that
earlier cases did exist, but we're simply
unidentified or misidentified.
Hantavirus strains had been previously
found in Europe, but the American strains
affect the lungs, and the respiratory system
while European strains cause hemorrhagic
fever with renal syndrome (HFRS).

30. Health Concerns
•Hantavirus is zoonotic, which means that it is a pathogen spread
from animals to people.
•It has not been shown capable of transferring from human to
human, and the HIPS causing strain is very limited in which
species of rodents can be carriers.
•The primary host of the HIPS pathogen is the deer mouse while
other species have been implicated, but either carried different
strains, or were unconfirmed carriers.

31. Health Concerns
•The commensal rodent species such as the house mouse, roof
rat, and Norway rat have not been shown to carry the strain
that causes HPS, but the Norway rat has been shown to carry
other strains that can cause hemorrhagic fevers and renal
failure.
•Therefore, limiting exposure of these commensal rodents is
important.

32. Health Concerns
Exposure to rodent feces, urine, blood and saliva are the most
common means of transfer from rodent to human for hantavirus. The
best method of controlling exposure therefore comes from controlling
the rodent problem and decontaminating suspected areas.
People and animals should stay away from suspected areas of
infestation until current activity can be ruled out and the entire area
properly sanitized.

33. Health Concerns
Hantavirus generally dies outside of the body of rodents within 48 hours, therefore
removing active rodent populations becomes important, and sustained sanitation
adds a second level of control in the case of unknown recurring infestations.
Sanitizing should always be done with all possible vectors of disease included
however, not just the suspected issue.
Cleaning and exclusion should be done in a manner that allows for control of all
possible rodent caused health issues.

34. Health
Concerns
•Leptospirosis is another condition that is
caused by exposure to a specific pathogen.
In this case, bacteria from the genus
leptospira are what cause the illness.
•Leptospirosis has been shown to cause
meningitis which is a type of swelling around
the brain stem. It can also cause liver failure,
kidney damage, and respiratory distress.

35. Health
Concerns
•These conditions are all serious and can
lead to death. The bacteria is usually
spread by contact with rodent urine, but if
the contamination spreads to pets, or
livestock infection can occur as a result of
exposure to the urine of otherwise
domesticated animals.
•Some pets can be vaccinated, and in cases
where this is appropriate it is
recommended.

36. Health Concerns
Removal of rodents, and rodent evidence is
suggested, but care should be taken with water
supplies that may be contaminated, and surfaces that
can have rodent urine on them.
The methods of cleaning, sanitation, and removal are
important since the primary route of infection is
through the skin, membranes, or into open cuts, and
sores on the body.

37. Health
Concerns
Water sources however do become contaminated,
as well as food preparation surfaces, and
dinnerware as a result of rodents crossing them.
This means that infection is also common from
ingestion. Proper disinfection techniques include
the use of sanitizers, and may require a lot of
scrubbing and ‘elbow grease'.
Contaminated water and food or feed should be
discarded and not used. Larger water sources such
as lakes, rivers and ponds are beyond the scope of
pest control technicians and not mentioned here.

38. Health Concerns
Rat bite fever is another condition associated with rodent
infestations. In spite of the name it is not always the
result of a bite from a rodent.
It can also occur as a result of consuming contaminated
food and water. As a result of ingestion the normal
symptoms of vomiting and sore throat may be more
severe.

39. Health Concerns
• The other symptoms include fever, swollen lymph nodes, joint pain, muscle pain,
headaches and rash, as well as localized swelling and even ulcers in the areas of
rodent bites or scratches.
• Streptobacillary RBF is one of the two types of rat bite fever and has an onset at
about 3-10 days, but in some cases won’t show for up to 3 weeks.
• This makes a diagnosis more difficult, since the original exposure may not be
remembered. Streptobacillary RBF is the type most associated with aches and
pains.
• The second type is Spirillary RBF which has symptoms appearing within 7-21 days

40. Health Concerns
Spirillary RBF is most associated with swelling
around the bite or wound, ulcers in the infected
area, and a fever that may come and go.
Rat bite fever however is not a major medical
concern and is rarely diagnosed in the United
States.

41. Part 4. Insect
disease vectors
and other
secondary pests
•While many insects are considered vectors
of disease, are of particular importance
with regards to rats.
•Rats, and several other urban animal
species are known carriers of the bacteria
that causes endemic typhus, sometimes
referred to as murine typhus (Rickettsia
typhus).

42. Insect disease
vectors and other
secondary pests
While many insects are considered
vectors of disease, are of particular
importance with regards to rats.
Rats, and several other urban animal
species are known carriers of the
bacteria that causes endemic typhus,
sometimes referred to as murine
typhus (Rickettsia typhus).

43. Insect disease
vectors and other
secondary pests
As rats enter a structure or sometimes nest
close to it, they bring fleas with them. The
fleas then enter the structure, or get onto
those that come outside.
These fleas that get onto unsuspecting
people have often contracted the typhus
causing bacteria and can spread it to those
unsuspecting people.
The infection generally occurs when fecal
matter from fleas gets into a flea bite, or
through the skin in some other way.

44. Insect
disease
vectors
and
other
secondary
pests
Many people scratching the bites don't realize
they are infecting themselves by forcing the fecal
matter into these areas.
Symptoms include headaches, fevers, muscle
pain, joint pain, nausea and vomiting. Some
people will develop rashes and neurological signs
such as confusion.
These symptoms can cause a misdiagnosis since
they resemble other similar, and dissimilar
conditions.

45. Insect
disease
vectors and
other
secondary
pests
Plague is another bacterial
condition often contracted from
fleas that are brought onto a
property or into a structure by
infected animals such as rats.
This can however be more
troublesome because if pneumonia
develops in a human host the
condition can then be spread from
person to person

46. Insect disease
vectors and
other secondary
pests
Likewise, flea bites are not the only way of
contracting it. Contact with any bodily fluid
from infected animals can lead to contracting
the serious condition that is identified by
fever, chills, muscle aches and swollen lymph
nodes that are referred to as buboes.
These buboes are the reason that the
condition is referred to as the bubonic
plague.

47. Rat and bird mites are secondary pests that can often
cause grief for a home owner and a pest control
technician.
When rodents and birds leave a
structure these insects are
sometimes left behind. They
then move into the human
occupied portion of the structure
and attack unsuspecting people
and pets.
In many cases rodents continue
to bring more of these insects,
and a less than complete rodent
control plan may provide for an
ongoing infestation of secondary
pests.

48. •Therefore, thorough exclusion is
recommended, removal of all nesting
material, and at least one application
of a proper miticide.
• If mite infestations continue it is
more likely that an exclusion plan has
failed, or nesting material was left
behind.
•The application of the miticide is to
give clients immediate relief, and is
not a complete solution by itself.

49. Photos by: Ed Freytag, City of New Orleans,Bugwood.org