Chiggers Those Hellish Creatures

 By guest blogger, Vi Hummel Shaffer a 28-year veteran SAR/R K9 Handler specializing in K9 Forensic Human Remains Detection, an instructor, consultant, and speaker. She is the author of K9 Teams: Beyond the Basics of Search and Rescue and Recovery published by Brush Education.

Technically, chiggers are not insects – they are “arachnids” in the same family as spiders and ticks. Chiggers are also known by other names around the world: some call them berry bugs, red bugs, harvest mites, harvest bugs, harvest lice, mower’s mites, scrub-itch mites and others. Their scientific name is “trombiculidae mites” and there are approximately 30 species known to attack humans and other animals.

Where They Can Be Found       

Chiggers like areas of high humidity. They live in every country around the globe except in high elevations or where it is too hot or dry. Fortunately, North American chiggers don’t seem to be carriers of major diseases unlike in East Asia and the South Pacific. In those areas’ chiggers can cause scrub typhus also known as Japanese river disease. This disease can cause fever, muscle pain, headaches, rash, gastrointestinal problems and coughing.

Chiggers live in damp areas such as grass – like fields, lawns, forests, along the edges of wooded areas, swamps, bogs, rotten logs and stumps, overgrown briar patches and other moist habitats near lakes and streams. However, although chiggers may be heavily concentrated in one spot, they can be virtually absent nearby areas.

When   

Chiggers are most abundant when weeds, grass and other vegetation are substantial – usually in spring, summer and early fall when temperatures are in the 70s and 80s. But they avoid temperatures hotter than 99⁰F (37.2⁰C) and become inactive at temperatures below 60⁰F (15.5⁰C) and 42⁰F (5.556⁰C) will kill the biting ones.

Who and How They Attack    

Only the larvae (baby chiggers) are parasitic! Nymph and adult stages do not “bite”. While adult chiggers average about 1/60 of an inch long (0.4mm) the larvae are only 1/100 to less than 1/150 of an inch (10.15 to 0.3 mm) in diameter. They are bright red, hairy, have six legs (larva pictured). Adult and nymph chiggers have eight legs. Some species of chiggers are yellow or straw-colored. After the chigger eggs hatch into larvae they don’t move very far by themselves. They congregate in groups on grass blades, low plants and bushes and small clumps of soil. They attach themselves to small mammals, birds, reptiles, rodents and humans (their least preferable host) who walk through the infested vegetation.

Larvae mites have claws that help them latch on to the host they choose – such as the shoes, clothing, fur/hair – and skin of animals. Generally, they crawl around and explore the host, sometimes for several hours, seeking a safe place before they feed. Bites can happen on any area of the body but mainly where there are folds, wrinkles or where skin in thinnest and easier to penetrate. Those areas are commonly where clothing is tight – around ankles at the sock line, around the waist, near the groin, behind knees, under the armpits – inconvenient places like panty lines, bra straps and there have been cases where they have made their way on to “private parts.” Chiggers can leave hundreds of bites on a host in just one exposure!      

Prevention 

Other than staying out of chigger infested areas – which isn’t always possible – searchers and those working in the field should wear long-sleeved shirts, tall boots with their trousers tucked into their socks and a belt to minimize chiggers’ ability to connect directly to skin under a shirt.

Insect repellent is also suggested. But even repellents that specifically state they repel chiggers may only afford some degree of protection. Over-the-counter insect repellent effectiveness usually lasts for several hours before needing reapplication. Those containing DEET (N,N-diethyl-meta-toluamide) may be applied directly to exposed skin but avoid getting it around or in the eyes. All repellents should be used according to label directions. If sunscreen is also used it should be applied first, rubbed into the skin and let absorb before using a repellent.

Long-lasting products such as those containing permethrin should only be sprayed on clothing (not on skin) and allowed to dry on the clothes for a couple of days before wearing. Permethrin sprays on clothing will remain effective even through a couple of washings. It is important to follow all label instructions. For double protection in heavily infested areas, it has been suggested to use repellent with DEET on your skin, and permethrin treated clothing. Sulphur powder applied to clothing has also been mentioned as providing some protection. But it has a horrible smell like rotten eggs.  

Author’s Note: Being the recipient of thousands of chigger bites through the years, and although trying various repellents, I have found one thing that has truly lessened them. Bounce Dryer Sheets! I have used them for years, shared them with others in the field, and they have helped! Take two fresh dryer sheets and wrap them around each ankle – that’s two sheets per ankle – under your socks. I also tuck some in my waistband and then sprayed myself with repellent. I don’t know if the “fragrance free” sheets or if any other brands work since I have only used the scented Bounce sheets.

“Bite”     

As previously stated, the larvae, not the adults or nymphs, are what does the damage. Chiggers don’t really bite nor do they “suck blood” or burrow into the skin. The larvae have tiny, sharp mouthparts that pierce the skin – poking a hole where they inject saliva containing digestive enzymes. Those enzymes break down and liquefy skin cells causing the human immune system to respond by hardening the cells all around the hole creating a hard feeding tube structure (referred to as a “stylostome”). It is through that tube that chiggers gain access to the digested skin cells where they constantly secrete saliva to liquefy new tissue. The larvae continue to feed sucking up the fluid until they are engorged. The enzymes are what causes the intense, relentless itching that begins several hours after the initial bite.

Because of the delay between the actual puncture and the itch, the host may not at first, associate it to their exposure to chiggers. The result of these bites will be clusters or groups of red pimple-like bumps or blisters whose itching usually peaks around 24 – 48 hours after the original piercing. Chigger larvae typically feed for three days before dropping off to find a place to digest their meal and molt into their next stage of life.

After Exposure: Clothing, shoes, gear (and dog) should be thoroughly brushed off immediately upon returning from the field. Once home, that clothing should be isolated from the rest of the laundry then washed in hot, soapy water. Boots should be left outside until cleaned. Dog bedding or vehicle kennel pads should also be cleaned.

A hot shower or bath should be taken as soon as possible with repeated soaping and vigorously scrubbing with a washcloth to dislodge any larvae that remain on the body. Although some chiggers may be forced off, the itching from the enzymes in the “tube” will still exist.

Some information sites suggest a cold shower should be taken, rather than hot, to help reduce inflammation from the bites and help relieve itching.

What to Do/Human Treatment (Note: This treatment information is a compilation of ideas from reputable sources. It is not medical advice.)

First of All, Don’t Scratch. Scratching can cause a secondary infection.

Don’t put clear fingernail polish on the bites to try to “suffocate” the chiggers. The chiggers may already be gone. Remember it is the enzymes already in your skin that cause the itching.

Don’t put bleach on the bites it doesn’t work! 

All itch relief remedies provide only temporary relief. The following suggestions are the most authoritative.

Unfortunately, No one remedy works equally well for most people and, even less encouraging it can take two to three weeks for chigger bites to heal!

Rubbing alcohol will burn when it touches a wound but it may have a little benefit and possibly kill any larvae if they are still attached.

Hot (or cold) showers and baths

Cold bath with a few scoops of colloidal oatmeal

Cold compresses

Applying wrapped ice to the bites

Over-the counter anti-itch creams, ointments and sprays.  If any contain hydrocortisone, consult with a doctor before using on children under the age of 12, or if pregnant or nursing.

Calamine or Pramoxine lotions

Menthol ointments (Vicks VapoRub)

Apple cider vinegar

Antihistamine pills such as Benadryl

Analgesics (pain relievers) may provide itch relief.

Ground up aspirin paste or baking soda paste applied to each bite.

Camphor Oil

In addition, antiseptic ointment will help prevent infection for bites that have been scraped by clothing or scratched.  For severe cases of chigger bites a physician should be consulted. Steroid shots may be prescribed to alleviate the itch and if infected, antibiotics may be needed.

Chiggers on Dogs

Although a dog’s fur can protect it from some chiggers they still latch on to other areas. Those less hair-covered places such as around the dog’s eyes, ears, legs and stomach are particularly vulnerable. Once on-board they will crawl around and also climb around down into the fur looking for a good, safe place to feed.

Chiggers or Fleas

Fleas prefer warm-blooded hairy animals. They can jump eight inches high and thirteen inches horizontally. Fleas feed on blood so there may be some “flea dirt” (dried blood from bites) present on the dog’s body as can be seen in this photo. There are usually three or four bites lined up in a row in an area. They are small red bumps with a halo-like ring around them.

Photo from PulpBits website

Chigger bites are in large, random clusters and look similar to small pimples, welts, blisters or hives.

Photo from University of San Francisco webpage

Sometimes chiggers can be identified by observing what looks look like paprika on the dog’s fur. Those almost microscopic reddish dots are larvae.

Indications of Chiggers on Dogs

Intense itching/scratching – typically starts three to six hours after exposure – that lasts for days is the most apparent indication. While not all dogs react with itching, some may develop an allergic reaction with hives or facial swelling.  As with humans, the itching enzymes will remain although the larvae will fall off after feeding for three or four days.

Clusters of Small, red crusty pimples, welts/bumps on skin which occur after several hours.

Red patches on exposed skin (can even be visible under their hair).

(If unsure of what the problem is, since other skin conditions may cause bumps, consult a veterinarian who can make the diagnosis.)

Treating Chigger Bites on Dogs

As previously mentioned, the dog should be brushed/wiped off immediately after returning from the field. It is recommended a soft cloth or vet-approved skin wipe be used around the sensitive areas. Chiggers can also infect a dog’s inner ear.

There are products/shampoos on the market to treat chigger bites on dogs but it is important to review them for safety and results. There are home-remedies (with mixture directions online) which may or may not be effective such as: bathing the dog in Epsom salts, a warm Colloidal Oat or Brewed Green Tea bath, Wrapped Ice Packs or Cold Compresses. Before using human treatments, a veterinarian should be consulted. The Vet may prescribe anti-parasitic sprays, dips, topical medication or suggest an antihistamine. In cases of severe infestation steroids may be prescribed. Remember continuous scratching can develop into bacterial infection which then would require antibiotics.

Prevention Veterinarian approved, dog medications for killing ticks and mites (Frontline, NexGard, Seresto, etc.) may help fend off chiggers. If chigger infested areas are within the dog’s home territory – Keep the dog away from them for about two weeks while those places are treated with pet-safe products.

Chiggers and the Ecosystem

After much research, due to curiosity about the “benefits” of chiggers, the most learned is that they feed on different foods at their different life stages. Larvae are parasitic while nymphs and adults feed only are various plant materials and smaller arthropods in the soil. Natural predators of chiggers (and other mites) are spiders, beetles, birds, lizards, centipedes, salamanders, certain species of ants and other small creatures which live in areas populated by chiggers.

Note from Susan: While this article applies to people and dogs, chiggers can bite cats and other animals as well.

The amazing ability of dogs to detect scent

In a recent study conducted by the University of Alberta, they determined that a dog could detect fire accelerants such as gasoline in quantities as small as one billionth of a teaspoon.

new ready

The study was conducted to determine the effectiveness of arson detection dogs. To test this the researchers used two dog-and-handler teams. One dog was trained to detect a variety of ignitable liquids, and the other was trained with gasoline. Interestingly, the dog trained on a variety of liquids performed well detecting all accelerants, but the dog trained on gasoline could not generalize to other accelerants at extremely low concentrations.

The reason for the tests was that accelerant dogs will give an indication at a site and when the material is tested in a lab, no trace of accelerant is found.

Those of us who use dogs for various scent work will find this information helpful. The study concluded that a dog could detect odor at one billionth of a teaspoon. In previous studies by Johnson and Johnson, they determined that a dog could detect any scent at one part per trillion.

The variables that must be considered in research such as this are:

The dog’s physical ability to detect odor. Even a good dog will have off days.

The trainer’s ability to train the dog.

The air flow at the testing site.

The age of the material, in other words, how old is the scent source?

And my last comment, if the dog who was trained to detect only gasoline would not generalize to other accelerants at a low level, he was doing what he was trained to do. It does not mean that the dog could not detect the low-level scents. The question that needs to be addressed is do the non-gasoline accelerants have a gasoline chemical that evaporates quickly that the dog would identify at a higher concentration, but at low levels are there other scents or chemicals in the accelerant that are residual which the dog is not trained to find? For example, a dog taught to follow human scent will never follow animal scent. Unless the other accelerants had the chemical composition of gasoline, the dog should not indicate it.

But this is a good study and does give us an idea of the concentration of scent that a dog can detect.

 

How animals detect odor

Prof. Nowotny, Director of Research and Knowledge Exchange in the University of Sussex’s School of Engineering and Informatics had determined that animals may not single out a specific odor when they look for a substance. He has found that animals may find it easier to detect a collection of odors instead of a single substance. If this is true, then most of the detection dog training that focuses on teaching a dog to look for one odor rather than a scent picture, may not be the best way to train a dog.

scout sar tracking

Scout following scent

One single odor does not exist in a natural environment, rather there are a collection of odors. When you consider that it is impossible to isolate a single odor in a natural environment, this discovery makes sense. Of course it is possible and often likely that a single odor is stronger than the surrounding odors, but still it is not the only odor present.

Professor Nowotny suggests that animal and human olfactory systems may not be made to do analytic smelling of pure odors. He uses the example of how an animal will give off pheromones, a complex set of odors, as a form of communication and that it is important that an animal recognize the entire chemical message and not a single element in the chemical message.

For years I have maintained that when teaching a dog scent work that there is no such thing as an uncontaminated scent article. Professor Nowotny has confirmed this with his latest research. Although more studies need to be done, and we should still train our dogs as we have in the past, it does open the door for a less narrow view of what dogs detect and how they detect it and may lead to new training methods. It is always good to “think outside the box.”

Sue Bulanda’s books

With the holidays fast approaching I thought I would post a list of the books that I have written. All but two of my books can be ordered from my website (www.sbuland.com) by clicking on the “books” tab. If you want a book shipped outside of the USA please email me for the correct postage. If you order my listed books you will get an autographed copy. I only have a few copies of Soldiers in Fur and Feathers so if you want that please email me first to see if I have any more. This book is out-of-print, so do not order it from my website.

K9 Obedience Training: Teaching Pets and Working Dogs to be Reliable and Free-Thinking.  This book shows you how to teach a dog the basic obedience that is the foundation for all other training. The methods used in this book allow the dog the freedom to think for themselves rather than perform in a robotic method where creativity is discouraged. Free-Thinking is necessary for all working dogs who cannot be trained for every situation that they encourage. Obedient disobedience is also covered. The book also explains what not to do and why. It includes basic handling and grooming techniques that are necessary for a well socialized dog. Some fun tricks are included.

K9 OBEDIENCE TRAINING COVER PRINT

K9 Search and Rescue Troubleshooting: Practical Solutions to Common Search-Dog Training Problems – explains the typical training problems and offers solutions that SAR dog handlers encounter when training their dogs. The solutions apply to all disciplines in canine search and rescue. It explains how the puppy stages of development can have lasting effects on the behavior and training of a dog. Often people adopt an older dog to train and do not understand why the dog behaves the way it does, this book gives insight to those issues. Although K9 Search and Rescue Troubleshooting: Practical Solutions to Common Search-Dog Training Problems is written for the SAR dog handler, the information contained in it applies to many training issues that are not related to SAR.

9781550597363

Soldiers in Fur and Feathers: The Animals That Served in WWI – Allied Forces: A unique, collection of accounts about many different animals that served in WWI. There are many rare photos. What is especially interesting about this book is that it includes many of the mascots that the soldiers kept. Some went into the trenches with the men. For example, there is an account about how a cat saved the life of a soldier, how a pair of geese slated to be Christmas dinner wound up being kept as mascots, and one soldier had a huge Golden Eagle as a pet. WWI was a transitional war from animal power to mechanization, therefore many species of animals served, such as oxen, horses, mules, camels, pigeons, and dogs in many capacities.

2012: Second Place Winner Non-Fiction, National League of American Pen Women; Finalist for the Alliance of Purebred Dog Writers Arthur Award, Certificate of Excellence for the Cat Writers Association of America.

Soldiers in Fur and Feathers

Faithful Friends: Holocaust Survivors Stories of the Pets Who Gave Them Comfort, Suffered Alongside Them and Waited for Their Return: This is the only book written about the animals of the Holocaust victims, recording a part of history that has been overlooked. Some of the stories are sad and some joyous, but all are a part of history. Learn about Nicholas the French Bulldog owned by a woman who was part of the French resistance, and how he came to tour with the German army. Also, the dogs who somehow survived the war and were reunited with their owners and many other stories about dogs and cats.

2012: Dog Writers Association of America, Maxwell Award.

Certificate of Excellence Cat Writers Association, 2012; National League of American Pen Woman 2nd place non-fiction, 2012.

holocaust book cover viewer

God’s Creatures: A Biblical View of Animals: explains the role that animals play in the Bible and how God uses them. It explores the nature of animals and miracles that involve them. The book explores many of the miracles that involve animals. It answers questions such as, do animals go to heaven, do they know and obey God, can they be evil?

AnimalsFrontCover72

Boston Terriers, a book all about this wonderful breed of dog. Learn about their care, training and personality. The book has fun sidebars that give personal accounts of Boston terriers.

First Place Maxwell Award for the Dog Writers Association of America, 2002. (only available on-line)

bost

Ready: The Training of the Search and Rescue Dog: Adopted worldwide as the training book for SAR dogs. This book has been in print since 1994 and is in its second edition. It gives the SAR dog handler a training plan for all disciplines of canine search and rescue.

First place for the National League of American Pen Woman’s biannual contest, 1996. Also nominated best book of the year, 1994 Dog Writers Association.

new ready

Ready to Serve, Ready to Save: Strategies of Real-Life Search and Rescue Missions: is about actual search and rescue missions giving the reader inside information about how searches work. It is useful as a tabletop training exercise for SAR units.

2000 Award winner for the National League of American Pen Women contest.

Ready serve

Scenting on the Wind: Scent Work for Hunting Dogs: helps the hunting enthusiast understand how weather, wind and terrain features affect scent. It is a great aid for people who compete in field trials or who do any kind of scent work with dogs.

scenting

Real Estate Today, Seller Beware! – is how to save money when selling your house. Available on Amazon

RE cover

 

Secrets of the Snout by Frank Rosell

Secrets of the Snout by Frank Rosell, University of Chicago Press, ISBN: 13: 978-0-226-53636-1, 265 pgs., $23.40.

franks book

Professor Rosell has done a wonderful job explaining how a dog’s nose works. He gives us accounts of different types of detection dogs which is a delight to read. The book is easy to read and understand because written for the average pet owner.

While other books have covered a dog’s scenting abilities, Professor Rosell has included the latest research along with keen insight to dog behavior. He explains what makes up scent and what a dog detects.

Each chapter features a specific dog’s scenting experience which helps the reader gain useful insight as to how dogs do their jobs. He explores topics such as, can a dog tell identical twins apart and other interesting experiments.

There are extensive notes for each chapter as well as a thorough index which makes it easy to locate specific material. I highly recommend this book for all working dog and pet owners who would like to understand their dog’s world of scent. This book was first published in Norway and was so popular that it was translated into English and published in the United States.

The Chapters include:

  1. Dogs at Work
  2. A Dog’s Sense of Smell
  3. A Good Judge of Character
  4. Pet Finder
  5. Search and Rescue
  6. On the Hunt
  7. Police Work
  8. Customs and Border Control
  9. Military
  10. Medical Detection
  11. Field Assistant
  12. Pest Detector and Building Inspector
  13. Other Work Tasks for Sniffer Dogs.

How animals detect odor

Professor  Nowotny, Director of Research and Knowledge Exchange in the University of Sussex’s School of Engineering and Informatics had determined that animals may not single out a specific odor when they look for a substance. He has found that animals may find it easier to detect a collection of odors instead of a single substance. If this is true, then most of the detection dog training that focuses on teaching a dog to look for one odor rather than a scent picture, may not be the best way to train a dog.

Waiting patiently to search croped (Jib a Border Collie)

One single odor does not exist in a natural environment, rather there are a collection of odors. When you consider that it is impossible to isolate a single odor in a natural environment, this discovery makes sense. Of course it is possible and often likely that a single odor is stronger than the surrounding odors, but still it is not the only odor present.

Professor Nowotny suggests that animal and human olfactory systems may not be made to do analytic smelling of pure odors. He uses the example of how an animal will give off pheromones, a complex set of odors, as a form of communication and that it is important that an animal recognize the entire chemical message and not a single element in the chemical message.

For years I have maintained that when teaching a dog scent work that there is no such thing as an uncontaminated scent article. Professor Nowotny has confirmed this with his latest research. Although more studies need to be done, and we should still train our dogs as we have in the past, it does open the door for a less narrow view of what dogs detect and how they detect it and may lead to new training methods.

Hydrating Working Dogs

Dogs who work in hot weather such as border patrol dogs, search and rescue dogs as well as military dogs often become dehydrated when they work in hot environments.

Scout SAR training window

Handlers of these dogs do not agree about how to hydrate their dogs to prevent heat stroke and dehydration. There are three major ways that handlers hydrate their dogs.

  1. Free access to drinking water
  2. Subcutaneous hydration (a needle under the skin) of water and electrolytes
  3. Drinks containing electrolytes

Researchers studied all three methods and found that they all worked. However, they found that by using a chicken flavored electrolyte drink, even dogs who were reluctant to drink, would drink more liquid.

The researchers tested the dog’s urine and found that they passed the sodium and therefore did not have a buildup of sodium in their body which had been a concern about using electrolyte drinks. Thus, drinking a chicken flavored electrolyte drink did not have any negative effects on the dogs.

Ghosts of the Buffalo Wheel by Joe Jennings

Ghosts of the Buffalo Wheel by Joe Jennings, 273 pgs., ISBN: 9781980726098, $11.50, self-published

5151SSoPllL._SX331_BO1,204,203,200_

This is the second book about Sam Webber and Gunny the SAR dog, The Ghosts of Iwo Jima was the first in the series. This adventure takes Sam, Gunny and the team to the Buffalo Wheel, also known as the Medicine Wheel which is a real life National Historical Landmark in Wyoming. Based on clues, the team was assigned to find the remains of Butch Cassidy.

Mr. Jennings did quite a bit of research about the Medicine Wheel and what really happened to Butch Cassidy and the Sundance Kid. He mentions historical data about the pair and theories about their fate in his book.

The story weaves in native American traditions and lore as well as forensic research techniques that are used to determine if the remains that are found are those of Butch Cassidy. There is also the drama of the search and an attempt to steal the supposed gold that Butch hid from an old robbery.

This book is as entertaining as Mr. Jennings first book and it is especially fun for SAR people to read. I highly recommend it.

 

K9 Search and Rescue Troubleshooting

K9 Search and Rescue Troubleshooting: Practical Solutions to Common Search Dog Training Problems by Susan Bulanda, publisher, Brush Education, ISBN: 978-1-55059-736-3 Autographed copies available at www.sbulanda.com also available on Amazon and Barnes & Noble.

9781550597363

My new book is now available! This book will help both the seasoned and inexperienced K9 handler. Many SAR units use a one-size-fits-all training method. When it does not work, they often do not know how to solve the training problem. This book explains how to fix those problems. Every dog is unique and what works for one dog may not work for another. Sometimes a small change in technique is all that is needed. Other times the handler is sending the wrong signal to the dog.

Getting the right dog or puppy is critical to the dog’s success. The book explains how to find the right breeder and puppy for SAR work. The way the puppy is handled during its stages of development can influence how the adult dog will react to training. If a handler is training an older dog, its early experiences can explain some of the training issues that a handler may have.

The book also explains the intelligence of dogs including the latest research about how they perceive life, their emotions and how they react to their owners. This knowledge will help a handler relate to their dog and recognize the message that they send to their dog. Although this book is written for SAR dogs, the information in it applies to all types of dog training, especially for working dogs.

The chapters include:

Finding a good SAR dog; Why dogs have training problems; What is scent; The uncontaminated scent article; Cross train a dog; SAR dog training methods; SAR dog training problems; and an appendix about the nature of scent.

Please Spread the Word!

 

 

A new device to help train explosives detection dogs

We depend upon bomb dogs to help protect us from terrorist attacks. Training them can be tricky. To help trainers and handlers, researchers have developed a real-time vapor analysis device called a Vapor Analysis Mass Spectrometer to help trainers and handlers understand what a dog detects when searching for explosive materials. When training a dog for any kind of scent work, it is important to hide items that are not scented as well as items with the target scent on them. Bomb dog trainers and handlers found that in some cases the dogs were indicating scent on the non-scented items. What the Vapor Analysis Mass Spectrometer showed in these cases that the dogs were correct because the non-scented items had picked up scent that drifted from the scented items.

lar & jib

By using the Vapor Analysis Mass Spectrometer during training, handlers and trainers will better be able to determine how accurate the dogs are in detecting explosive material.

The lesson from this research applies to all types of scent work with dogs. It shows us that items handlers think are not contaminated may be contaminated. Ultimately, it means that whoever handles scented items and non-scented items for training must take extra precautions to ensure that non-scented items are not contaminated. This can be especially tricky when training dogs in search and rescue where the handler has no control over the elements (weather, etc.) that can cause scent to drift.

www.sciencedaily.com/releases/2017/06/170628131349.htm