© 2019 Copyright by P. K. H. Groth, Denver, Colorado, USA All rights reserved - See contact page for for permission to republish article excerpts.
Rodent Problems and Disease
What you don’t know might not annoy you, but it might kill you. I include this section on rodents which you might encounter while elk hunting in the Rockies, but it is also pertinent to all US hunters who have a hunting cabin or hunt where there are derelict old barns and buildings. Rodent carried diseases can be avoided if you know the dangers and properly clean your hunt camp cabins. Critters will attempt to relocate from fields to human habitation with the advent of cold weather. That is about hunting season! This includes house mice, deer mice which can carry the deadly H antavirus notorou virus , and pack rats which can mess up a camp and cart off possessions. We have been plagued with rodents in our Wyoming antelope hunting cabin. It took quite a while to understand their habits, the ways to discourage them , and how to efectively trap them. I might as well save you some time by passing on our experience. (Photos from Wikipedia ) House mice: ( Mus musculus ) are mostly associated with human habitation. The mice vary in color, but are normally gray in non- laboratory breeding situations. They have a pointed snout, small round eyes and naked ears and tails. The tails are used for precise body temperature contol, so tails of southern mice (as shown) are longer than our northern mice. These mice communicate with high pitch squeaking. Both common mice and deer mice can wiggle through a 3/8 to 1/2 inch opening (depending on age and size) and enlarge holes with gnawing as they grow. Deer mice : (Mus peromyscus ) are the most common mammal in the US, and have a range from Canada to Mexico. They are not not noticed much because they generally live scattered outdoors until cold weather arrives. There are seven varieties of deer mice and only mouse experts can distinguish the difference. The western US deer mouse Peromyscus manicalatus typically has a two-toned body, with a gold to mixed gold-gray top, white legs, and a distinct white belly and white tail bottom. The tail has short hair, again with the bottom white and a colored top appearing as a stripe. The snout is more stubby than the house mouse Deer mice usually remain mute, but communicate danger with coded foot thumping. They can jump three feet and are good climbers. They are omnivorous, eating plant and animal matter - insects, worms, seeds, nuts, flowers, fruit and even their own feces (coprophagy) if necessary. In the fall and winter they develop a craving for fat, to the extent they will resort to consume bars of soap even scented soap! Deer mice move into buildings, sheds, and wood piles with the onset of winter. Favorite places to nest inside are beds and upholstered chairs where they can use stuffing for nests. They are excellent squirmers, the young being able to squeeze through a hole the size of a shirt button. Deer mice may have 5-11 kits 3-4 times a year; young reach puberty in a month. Over population can rapidly occur in warm years with good extended food supplies, delayed early frost kill, and reduced number of predators. Deer mice infected with hanta virus do not show any signs of sickness, being immune to the virus. Some colonies have up to 70% infected mice. Deer mice transmit the hanta virus via their blood, saliva and urine, especially if these liquids are dried and become airborne by natural drafts or human activities like vacuming, sweeping or shaking bedding etc. Eating contaminated food or drinking from cans whose tops have been contaminated by urine is another transmission source. The hanta virus is believed to be viable (contractable) on surfaces for seven to eight days. Trapping Mice and Rats Poisons: I strongly recommend you do not use poisons. They enter the food chain when cats, dogs, birds and other animals eat the poisoned rodents. Warfarin-based poisons that make a rodents exit a building to find water are particulary damaging to the ecosystem. Poisons may be eaten by children. Mice and rats decaying in buildings is not sanitary, nor is the aroma appreciated. Deer mouse urine is a lingering danger because of the hanta virus. Bait: Use peanut butter worked well into the trap trigger. Let the peanut butter dry 2-3 days on a paper blotter which removes oil to make a thicker paste. This will prevent small mice and insects from licking away the gooey butter. Packrats like fruit in the fall and winter, especially a small chunk of aromatic apple. A better mouse trap can be devised by placing a vegetable twisty wire around the trap trigger (pull off the plastic foil-wrapped vegetable twisties work easier). This makes the mouse work harder to get the bait and increases trapping success (see trap photo). Trap placement: Place traps in a protected place or box along walls outside and insides. The box prevents killing birds and squirrels, and reduces rebaiting if wind and rain trips traps, and trap avoidance training of your rodent prey. Mouse traps should be placed on newspaper or cardboard. This prevents soiling of floor with rodent feces, blood and hazardous urine if a deer mouse is trapped. (The hanta virus is transmitted in mouse urine which may be expelled with death and rigor mortis contractions.) Use plastic newspaper bags as gloves and handle the trap cautiously and slowly. Invert the plastic bag and throw out the trap with the deer mouse; do not use it again.) Hunting Camps, Sheds, cabins and Barns: It is recommended people open all doors and windows and remain outside a while to let fresh air air into little used buildings to let air and to let dust circulate out. This will reduce the inhalation of dried deer mouse urine virus microcrystals wafted up by air currents. It also allows mice to calmly leave which is very important. Mice   commonly   urinate   when   panicked   to   run   fast. (Hawks with UV light sensitive eyes can see mouse urine trails when hunting.) There are six common ways to contract the hanta virus. 1.) Breathing in airborne mouse urine or droppings crystals/dust/particles when cleaning a shed, barn, garage with a broom, vacuum cleaner, pitchfork or shovel which raises dust. Shed cleaning should not be done within 7-8 days (thought to be life viability span of the virus on surfaces) of the last mouse infestation. Cleaning should be with soapy Chorlox water to prevent dust from rising. 2.) Touching the mouth or nose aftter contact with mouse urine, saliva, feces, or blood (such as after handling traps or dead mice. Do not handle live deer mice, since a bite may transmit the virus to you. 3.) Eating food contaminated by urine, droppings or saliva of an infected mouse; dispose of all contaminated food. Wash food can tops and bottles if they were in a contaminated area or if they were in outside storage). 4.) Being bitten by an infected mouse. Never domesticate a wild mouse as a pet, even if it seems a cute thing! 5.) Pets bringing in a mouse that is then handled so there is contact with urine, blood, feces. 6.) Hikers and campers should be careful when seeking shelter in trails helters and old buildings, especially in low altitude areas where mice are not killed by winter cold. How prevalent is Hanta: The hanta virus is thought to be indigenous. It was not recognized until about twenty years ago when the deer mouse was discovered to be the host and and the virus was recognized as the cause for historic, new reports of sporadic occurrences of a strange “new” illness. Recognition of more cases in the US caused the US Center for Disease Control and Prevention to start monitoring cases. In the ten years of monitoring so far, there were 690 recognized   and   reported cases in 35 states, or about 6.9 per year of Hantavirus Pulmonary Syndrome (HPS)illnesses in Colorado. The fatality rate was 38%. The map below illustrates the range of recognized hanta cases and number of people contracting hanta during the last ten years. Cumulative (10 year) Case Count Per State Valid as of January 8, 2016 US Center for Disease Control and Prevention Hantavirus Pulmonary Syndrome (HPS) Cases, by State of Reporting Total Cases: N=690 in 35 States Not displayed: 2 c ases reported with presumed exposure outside the USA Hanta virus symptoms: Early stage symptoms- fever, chills, muscle aches of large muscle groups like the hips, thighs, shoulders and abdomen; dizziness, fatigue, nausea, vomiting, diarrhea, general gut pains. Advanced stage symptoms progressive shortening of breath, labored breathing, increasingly faster heart and breathing rate (signs of lungs filling with water = Hanta pulmonary edema, resulting in death without treatment.) There are no medical cures for the virus, so hospital life support methods are the only treatments. Closing note on hanta: You may think I over emphasize the hanta virus threat. The chances of contracting it are slim on a statistical basis. However, IF you get the virus the consequences are great. This was “brought home” to us when a friend of our ranch hosts died quickly after cleaning out a shed. A little caution and extra cleaning vigilance are worth preventing a death of a buddy, child or mate; guilt from negligence lasts a lifetime.
© 2016 -2017 Copyright by P. K. H. Groth, Denver, Colorado, USA All rights reserved - See contact page for for permission to republish article excerpts.
Rodent Problems and Disease
What you don’t know might not annoy you, but it might kill you. I include this section on rodents which you might encounter while elk hunting in the Rockies, but it is also pertinent to all US hunters who have a hunting cabin or hunt where there are derelict old barns and buildings. Rodent carried diseases can be avoided if you know the dangers and properly clean your hunt camp cabins. Critters will attempt to relocate from fields to human habitation with the advent of cold weather. That is about hunting season! This includes house mice, deer mice which can carry the deadly H antavirus notorou virus , and pack rats which can mess up a camp and cart off possessions. We have been plagued with rodents in our Wyoming antelope hunting cabin. It took quite a while to understand their habits, the ways to discourage them , and how to efectively trap them. I might as well save you some time by passing on our experience. (Photos from Wikipedia ) House mice: ( Mus musculus ) are mostly associated with human habitation. The mice vary in color, but are normally gray in non- laboratory breeding situations. They have a pointed snout, small round eyes and naked ears and tails. The tails are used for precise body temperature contol, so tails of southern mice (as shown) are longer than our northern mice. These mice communicate with high pitch squeaking. Both common mice and deer mice can wiggle through a 3/8 to 1/2 inch opening (depending on age and size) and enlarge holes with gnawing as they grow. Deer mice : ( M u s p e r o m y s c u s ) are the m o s t c o m m o n mammal in the US, and have a range from Canada to Mexico. They are not not noticed much because they generally live scattered outdoors until cold weather arrives. There are seven varieties of deer mice and only mouse experts can distinguish the difference. The western US deer mouse Peromyscus manicalatus typically has a two- toned body, with a gold to mixed gold-gray top, white legs, and a distinct white belly and white tail bottom. The tail has short hair, again with the bottom white and a colored top appearing as a stripe. The snout is more stubby than the house mouse Deer mice usually remain mute, but communicate danger with coded foot thumping. They can jump three feet and are good climbers. They are omnivorous, eating plant and animal matter - insects, worms, seeds, nuts, flowers, fruit and even their own feces (coprophagy) if necessary. In the fall and winter they develop a craving for fat, to the extent they will resort to consume bars of soap even scented soap! Deer mice move into buildings, sheds, and wood piles with the onset of winter. Favorite places to nest inside are beds and upholstered chairs where they can use stuffing for nests. They are excellent squirmers, the young being able to squeeze through a hole the size of a shirt button. Deer mice may have 5-11 kits 3-4 times a year; young reach puberty in a month. Over population can rapidly occur in warm years with good extended food supplies, delayed early frost kill, and reduced number of predators. Deer mice infected with hanta virus do not show any signs of sickness, being immune to the virus. Some colonies have up to 70% infected mice. Deer mice transmit the hanta virus via their blood, saliva and urine, especially if these liquids are dried and become airborne by natural drafts or human activities like vacuming, sweeping or shaking bedding etc. Eating contaminated food or drinking from cans whose tops have been contaminated by urine is another transmission source. The hanta virus is believed to be viable (contractable) on surfaces for seven to eight days. Trapping Mice and Rats Poisons: I strongly recommend you do not use poisons. They enter the food chain when cats, dogs, birds and other animals eat the poisoned rodents. Warfarin-based poisons that make a rodents exit a building to find water are particulary damaging to the ecosystem. Poisons may be eaten by children. Mice and rats decaying in buildings is not sanitary, nor is the aroma appreciated. Deer mouse urine is a lingering danger because of the hanta virus. Bait: Use peanut butter worked well into the trap trigger. Let the peanut butter dry 2-3 days on a paper blotter which removes oil to make a thicker paste. This will prevent small mice and insects from licking away the gooey butter. Packrats like fruit in the fall and winter, especially a small chunk of aromatic apple. A better mouse trap can be devised by placing a vegetable twisty wire around the trap trigger (pull off the plastic foil-wrapped vegetable twisties work easier). This makes the mouse work harder to get the bait and increases trapping success (see trap photo). Trap placement: Place traps in a protected place or box along walls outside and insides. The box prevents killing birds and squirrels, and reduces rebaiting if wind and rain trips traps, and trap avoidance training of your rodent prey. Mouse traps should be placed on newspaper or cardboard. This prevents soiling of floor with rodent feces, blood and hazardous urine if a deer mouse is trapped. (The hanta virus is transmitted in mouse urine which may be expelled with death and rigor mortis contractions.) Use plastic newspaper bags as gloves and handle the trap cautiously and slowly. Invert the plastic bag and throw out the trap with the deer mouse; do not use it again.) Hunting Camps, Sheds, cabins and Barns: It is recommended people open all doors and windows and remain outside a while to let fresh air air into little used buildings to let air and to let dust circulate out. This will reduce the inhalation of dried deer mouse urine virus microcrystals wafted up by air currents. It also allows mice to calmly leave which is very important. Mice    commonly urinate   when   panicked   to   run   fast. (Hawks with UV light sensitive eyes can see mouse urine trails when hunting.) There are six common ways to contract the hanta virus. 1.) Breathing in airborne mouse urine or droppings crystals/dust/particles when cleaning a shed, barn, garage with a broom, vacuum cleaner, pitchfork or shovel which raises dust. Shed cleaning should not be done within 7-8 days (thought to be life viability span of the virus on surfaces) of the last mouse infestation. Cleaning should be with soapy Chorlox water to prevent dust from rising. 2.) Touching the mouth or nose aftter contact with mouse urine, saliva, feces, or blood (such as after handling traps or dead mice. Do not handle live deer mice, since a bite may transmit the virus to you. 3.) Eating food contaminated by urine, droppings or saliva of an infected mouse; dispose of all contaminated food. Wash food can tops and bottles if they were in a contaminated area or if they were in outside storage). 4.) Being bitten by an infected mouse. Never domesticate a wild mouse as a pet, even if it seems a cute thing! 5.) Pets bringing in a mouse that is then handled so there is contact with urine, blood, feces. 6.) Hikers and campers should be careful when seeking shelter in trails helters and old buildings, especially in low altitude areas where mice are not killed by winter cold. How prevalent is Hanta: The hanta virus is thought to be indigenous. It was not recognized until about twenty years ago when the deer mouse was discovered to be the host and and the virus was recognized as the cause for historic, new reports of sporadic occurrences of a strange “new” illness. Recognition of more cases in the US caused the US Center for Disease Control and Prevention to start monitoring cases. In the ten years of monitoring so far, there were 690 recognized   and   reported cases in 35 states, or about 6.9 per year of Hantavirus Pulmonary Syndrome (HPS)illnesses in Colorado. The fatality rate was 38%. The map below illustrates the range of recognized hanta cases and number of people contracting hanta during the last ten years. Cumulative (10 year) Case Count Per State Valid as of January 8, 2016 US Center for Disease Control and Prevention Hantavirus Pulmonary Syndrome (HPS) Cases, by State of Reporting Total Cases: N=690 in 35 States Not displayed: 2 c ases reported with presumed exposure outside the USA Hanta virus symptoms: Early stage symptoms- fever, chills, muscle aches of large muscle groups like the hips, thighs, shoulders and abdomen; dizziness, fatigue, nausea, vomiting, diarrhea, general gut pains. Advanced stage symptoms progressive shortening of breath, labored breathing, increasingly faster heart and breathing rate (signs of lungs filling with water = Hanta pulmonary edema, resulting in death without treatment.) There are no medical cures for the virus, so hospital life support methods are the only treatments. Closing note on hanta: You may think I over emphasize the hanta virus threat. The chances of contracting it are slim on a statistical basis. However, IF you get the virus the consequences are great. This was “brought home” to us when a friend of our ranch hosts died quickly after cleaning out a shed. A little caution and extra cleaning vigilance are worth preventing a death of a buddy, child or mate; guilt from negligence lasts a lifetime.