Dangerous Critters

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Dangerous Critters?

• WY MSHA State Grant Program
• Gillette Campus of Sheridan College
• Western Wyoming Community College, Green River
  Center

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Are these critters REALLY dangerous?
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Dangerous Critters

• Venomous Spiders
• Mice Rats
• Mosquitos

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(No Transcript)
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DANGEROUSLY VENOMOUS SPIDERS
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DANGEROUSLY VENOMOUS SPIDERS

• Hobo Spider
• Widow Spider
• Recluse Spider
• Yellow Sac Spider

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Hobo/Brown Recluse Spider distribution
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Hobo Spider

• Pacific Northwest is normal range
• Enter homes July thru October
• Rarely found high on walls/ceilings
• Like mosquito bite, but turns into slow healing
  blister-like lesion easily infected
• Female 8-11 mm, Male 11-16 mm
• Light to Med brown, 2 dark stripes on thorax,
  light strip on midline of abdomen broken by light
  chevron markings

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Hobo Spider poisoning

• Male venom may be more potent than female
• Subadults venom may be more potent than adults
• Red area immediately after bite
• Fades to mosquitoe-like bump
• Incorrectly referred to as an aggressive house
  spidervery fast spidervery poor eyesight

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Hobo Spider poisoning

• Within 24-48 hrs, blisters may occur
• Next 24 hrs, blisters may rupture, leaving open
  ulceration
• Next few days a scab forms, giving a bulls-eye
  appearance
• Scab sloughs, leaving a scar in /- 45 days
• Some instances, as with fatty tissue areas,
  lesions can become deep and extensive (2-3 yrs to
  heal)

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Hobo Spider poisoning

• Other long-term effects
• Intractable burning pain
• Damage to blood vessel valves
• Cyst formation
• Multiple lesions from gravitational drift
• 15 of cases severe enough to require
  hospitalization
• In severe cases, bone marrow failure can develop,
  which causes death

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Black Widow Spider

• Throughout US
• Indoors year round, also outdoors
• Usually in seldom disturbed locations
• Web is approximately 12 in diameter
• Black color with red or orange hourglass marking
  on underside of abdomen (female only)
• Male 7-10mm, Female 12-13mm

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Black Widow Spider Bite

• Two tiny red dots, painful immediately
• Increased body temperature, sweating, nausea
• Some victims experience anxiety, profuse
  sweating, hair standing on end, increased blood
  pressure

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Black Widow Spider Bite

• No tissue necrosis
• Potent neurotoxin induces severe muscle cramping
  spasms, beginning in large muscles of legs or
  abdomen
• Abdomen can exhibit board-like rigidity
• Severe cases include paralysis, stupor, and
  convulsions, death in small percentage of cases
  (small children, elderly)

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Brown Recluse Spider(Violin Spider)

• Midwest and southern US (may be some apparent
  reports in WY)
• Sticky webs under rocks, etc.
• Enter homes, cellars, barns
• Male Female 6-12mm
• Tan to dark brown
• Fiddle shape markings on top of thorax

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Brown Recluse poisoning

• Bite usually not felt, but produce immediate
  stinging like bee sting
• Tissue becomes swollen
• Flu-like symptoms
• Fever, nausea, chills, aches

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Brown Recluse poisoning

• Painful ulceration develops
• Skin and musscle tissue dies, leaving a deep
  infected wound that enlarges, fails to heal or
  heals slowly (necrosis)

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Yellow Sac Spider

• Throughout US
• Indoors year round, mostly early autumn
• Build a silken sac in upper corners of ceilings
• Bite is slight burning sensation
• Some swelling
• Male 4-8mm, Female 5-10mm
• Pale yellow to green in color, legs and abdominal
  midline slightly darker

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Yellow Sac Spider bite

• Least known clinically significant spider
• Capable of causing a painful bite with necrotic
  lesion
• Not as severe as brown recluse or hobo
• Bites sometimes cause systemic effects
• Very prone to bite defensively (more than other
  significantly venomous spiders)

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Yellow Sac Spider bite

• Some bites in unusual areas (autos, swimming
  pools)
• Likely that many US cases of necrotic arachnidism
  ascribed to brown recluse are actually yellow sac
  spider bites

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HANTAVIRUS PULMONARY SYNDROME (HPS)
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HANTAVIRUS PULMONARY SYNDROME - SOME HISTORY

• First noted during an outbreak in the Four
  Corners area in May 1993 with several young
  apparently otherwise healthy young people dying
• Researchers discovered a previously unknown type
  of hantavirus, carried primarily by the deer
  mouse
• Virus called Sin Nombre virus (SNV) and the
  disease it caused was named Hantavirus Pulmonary
  Syndrome (HPS)
• Further medical research revealed that HPS was
  not new and located the first case (through
  records and tissue analysis) in Utah in 1959

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RODENTS KNOWN TO CARRY HANTAVIRUS PULMONARY
SYNDROME

• Deer Mouse
• White-footed Mouse
• Rice Rat
• Cotton Rat

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Deer Mouse

• Head body about 2-3 inches long-tail adds
  another 2-3 inches
• Gray to reddish brown
• Underbelly always white
• Tail has sharply defined white sides
• Found almost everywhere in North America
• Prefers woodlands, but found in desert areas also

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White-Footed Mouse

• Hard to distinguish from Deer Mouse
• Head body about 4 inches-tail adds 2-4 inches
• Pale brown to reddish brown
• Underside and feet are white
• Found southern New England, Mid-Atlantic,
  southern, midwestern, western states Mexico
• Prefers wooded brushy areas

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Rice Rat

• Head body 5-6 inches-plus a 5-7 inch tail
• Short, soft, grayish brown fur on top, gray or
  tawny underneath
• Feet are whitish
• Likes marshy areas and is semiaquatic
• Found in the southeastern US Central America

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Cotton Rat

• Head body 5-7 inches w/ tail 3-4 inches more
• Hair is longer and courser than deer mouse,
  grayish brown to grayish black
• Prefers overgrown areas w/ shrubs tall grass
• Found in southeastern US, Central South America

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SYMPTOMS OF HPS

• Early symptoms include
• Fatigue, fever, muscle aches (especially large
  muscle groups thighs, hips, back, shoulders)
  universal symptoms
• May also have headaches, dizziness, chills,
  abdominal problems (nausea, vomiting, diarrhea,
  pain) experienced by /- ½ of victims
• Incubation time is unclear at this time
• Limited info indicates 1 to 5 weeks

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SYMPTOMS OF HPS

• Late symptoms include
• Coughing, shortness of breath universal
  symptoms
• Very uncommon symptoms
• Earache, sore throat, and rash

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HANTAVIRUS PULMONARY SYNDROME

• Person to person contamination of HPS is unlikely
• Deer mice (cotton rice rats-SE US, white-footed
  mice-most of US) are the most common carrier of
  HPS
• Rodents shed the virus in their urine,
  droppings, and saliva
• Mainly transmitted to humans when we breathe air
  contaminated with the virus

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HANTAVIRUS PULMONARY SYNDROME

• Contamination happens when fresh rodent urine,
  droppings or nesting material is stirred up into
  the air we breathe this process is called
  aerosolization
• Rodent bites are very rare mode of infection
• May be able to contract virus if you touch
  contaminated object, then touch your nose or
  mouth
• Suspected that you can be infected by eating food
  contaminated with rodent urine, droppings, or
  saliva

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HANTAVIRUS PULMONARY SYNDROME

• Disease transmission can happen any place rodents
  have infested such as homes, barns, sheds,
  outbuildings, warehouses, summer homes, etc.
• Preventing rodents from infesting areas where you
  live and work is extremely important
• Disinfecting rodent-infested areas is very
  important to preventing the disease

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HOW TO PREVENT HPS

• Avoid contact with rodent infested areas
• Closed up rooms, cabins, warehouses
• Housecleaning activities in rodent infested areas
• Really stirring up the dust
• Large populations of rodents

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HOW TO PREVENT HPS

• Make your home, workplace, summer home or
  campsite unattractive to rodents
• If you dont provide rodents with food and
  nesting material
• You are much less likely to come into contact
  with them!

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HOW TO PREVENT HPS

• Recent research indicates that
• Many people who became ill with HPS got the
  disease after frequent contact with rodents
  and/or their droppings around home or work
• Thereforeit makes sense to try to keep your
  home, vacation place, workplace, or campsite clean

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HOW TO PREVENT HPS

• Indoor Prevention Strategies
• Keep your space clean
• Keep tight lid on garbage
• Set keep spring loaded traps
• Set EPA approved rodent bait
• Use flea killer if bubonic plague is an area
  concern
• Seal all entry holes ¼ inch and larger

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HOW TO PREVENT HPS

• Outdoor Prevention Strategies
• Clear brush, grass, junk from around buildings
• Use metal flashing around base of wooden,
  earthen, adobe (to 12 above ground, 6 into
  ground)
• Elevate hay woodpiles
• Trap rodents outside
• Encourage presence of natural preditors (snakes,
  owls, hawks, etc.)

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HOW TO PREVENT HPS

• Remembergetting rid of all rodents isnt
  feasiblebut with ongoing effort, you can keep
  populations very low

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COMMON SIGNS OF RODENT INFESTATION

• You see rodent droppings
• You see signs of rodent nesting
• You find food containers that appear to be
  nibbled
• You find signs of feeding stations
• You find evidence of gnawing
• You notice an odd, stale smell
• You see a mouse in your area

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How to clean up infested areas

• Open buildings or closed areas and air them out
  before cleaning
• Wear personal protective equipment
• Latex or nitrile gloves and P100 respirator
• Dont stir up dust by sweeping or vacuuming
• Thoroughly wet contaminated areaslet stand 5
  minutes
• Most general purpose disinfectants, household
  detergents are effective
• Hypochlorate solution (mix 1 ½ cups bleach in 1
  gallon of water) may be used in place of
  commercial disinfectant

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How to clean up infested areas

• Once contaminated area is wet, take up
  contaminated materials with damp towel, then mop
  or sponge area with disinfectant
• Spray dead rodents with disinfectantdouble bag
  with all cleaning materials and bury or burn
• Disinfect gloves before taking them off
• After taking off the gloves, thoroughly wash
  hands with soap and warm water

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WEST NILE VIRUS
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WEST NILE VIRUS

• No documented cases in Western Hemisphere until
  1999
• In 1999 2000 WNV encephalitis reported in New
  York City Metro area, New Jersey, and Connecticut
  83 cases, 9 deaths
• In 2001 WNV occurred in 10 states w/ 66 cases, 9
  deaths
• In 2002 WNV spread to 44 states w/4,156 cases,
  284 deaths

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Overview of West Nile Virus (WNV)

• WNV is a mosquito-borne disease that can cause
  encephalitis or meningitis
• Encephalitis is an inflammation of the brain
  tissue
• Meningitis is an inflammation of the membranes
  that envelop the brain or spinal cord

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WEST NILE VIRUS

• Transmitted to humans via mosquito bites
• Mosquitoes are infected by feeding on infected
  birds that have high level of WNV in their blood
• WNV is NOT transmitted from person to person
• No evidence that people get WNV from handling
  live or dead infected birds (use barriers as a
  precaution anyway)

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WEST NILE VIRUS

• Most WNV infected humans have no symptoms
• Small proportion develop mild symptoms including
  fever, headache, body aches, skin rash, swollen
  lymph glands West Nile fever
• More serious infections include high fever,
  headache, neck stiffness, stupor, disorientation,
  coma, tremors, convulsions, paralysis West Nile
  encephalitis

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WEST NILE VIRUS

• Less than 1 develop more severe symptoms
  including meningitis or encephalitis
• Estimated 1 in 1000 (0.1) developing
  encephalitis die
• No specific treatment or vaccination

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WEST NILE VIRUS

• Prevention is your best course of action!
• Avoid mosquito bites-use DEET
• Clean out mosquitoes where you work and play

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WEST NILE VIRUS US Distribution (from USGS)

• West Nile was first isolated in 1937known to
  cause infection and fever in humans in Africa,
  West Asia, and Middle East

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WEST NILE VIRUS US Distribution (From CDC)
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WEST NILE VIRUS WY Distribution

• Avian (Bird) cases by county

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WEST NILE VIRUS WY Distribution

• Animal cases by county

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WEST NILE VIRUS WY Distribution

• Human Cases By County

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WEST NILE VIRUS Prevention

• When outdoors, wear clothing that covers the skin
• Apply effective insect repellent to clothing
  exposed skin (DEET, etc.)
• Curb activity during dawn dusk
• Apply screens to doors windows regularly
  maintain them
• Reduce the amount of standing water around home
  or work

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PLEASE REMEMBER!

• Safety and Health IS NOT just a 9 to 5 job!
  You should be safe AT HOME as well as AT WORK!