Welcome to the Arizona Sonora Desert

The following has been designed by the veterinarians and technicians here at Orange Grove Animal Hospital to give an overview of the diseases and dangers our beautiful Sonoran Desert has to offer. If you have any questions about the topics discussed, feel free to talk to our knowledgeable staff.

Coccidioidomycosis (Valley Fever)

Coccidioidomycosis, more commonly known as Valley Fever, is caused by the fungus, coccidioides immitis, that lives about 12-18 inches down in our soil.  It can be found from California to Texas and as far north as Nevada and southern Utah. The spores from the fungus become airborne when ever the soil is disturbed by activities such as construction, gardening, landscaping, and digging done by pets. Once airborne, these spores are inhaled by people and animals.  Studies have shown that every person and animal is exposed to the coccidioides immitis spore within the first year of residence (either by birth or relocation) and that part time visitors have the same rate of exposure and infection as full time residents.  A large portion of the residents of our state have no clinical symptoms as the immune system quickly deals with the invader.  In some pets and people, clinical symptoms may develop and blood tests reveal that the pet has Coccidioidomycosis or Clinical Valley Fever.

There are two forms of Coccidioidomycosis, Pulmonary (involving the lungs) and Disseminated (involving any other organ or organ system outside of the lungs).  The following table is a list of common symptoms of both forms of this disease.

Pulmonary

Dry, Non-Productive Cough

Fever

Reduced Appetite

Lethargy

Weight Loss

If your dog or cat develops any of these symptoms or just seems off, you should see your veterinarian immediately. If you are visiting a veterinarian out of state, please mention that you have recently visited or spend part of the year here so that he or she is aware that your pet may have symptoms of a disease not native to that area. The only accurate way of diagnosing Valley Fever is to perform diagnostic tests such as blood work and/or radiographs.  If your pet is positive, your veterinarian will prescribe an anti-fungal medication for your pet to take and talk to you about the schedule for retesting and estimated length of treatment.

For more in depth information go to our Valley Fever page or visit the University of Arizona’s Valley Fever Center for Excellence at https://vfce.arizona.edu/valley-fever-dogs 

Ehrlichiosis

Another disease of significance is Ehrlichiosis, otherwise known as Tick Fever.  While we don’t generally have the right climate for fleas, we do have the perfect climate for Ticks, particularly the Brown Dog Tick.  This tick prefers dogs to any other species and is mainly found in areas where dogs live or have lived.  These ticks also carry a parasite called Ehrlichia spp.  There are several species of this parasite and all of them affect one or more types of blood cells.  It is contracted when an infected tick picks your dog as its next meal.  Within 1-3 weeks after the bite, the first symptoms may appear. In many cases, the owner never noticed the tick was on their pet.  There are two types of Ehrlichiosis, Acute and Sub-Clinical.  The following is a list of symptoms for both types:

Acute Ehrlichiosis

Sudden, spontaneous bleeding

Reduced appetite

Weight loss

Depression

Fever

Distressed breathing

Head tilt or uncoordinated movement

Lethargy

If your dog has any of these symptoms, you need to visit your veterinarian immediately.  He or she will do blood tests to check for the most common species, as well as blood cell counts and chemistries. Depending on how clinically ill your dog is, your veterinarian may recommend hospitalization for a short period, especially if your dog is dehydrated, severely anemic or is actively bleeding.  With or without hospitalization, your veterinarian will prescribe a medication that is generally effective in killing the parasite. He or she will explain the need for re-testing after the initial course of medication and the potential that it may take repeated courses in order to fully kill all remains of the parasite.

Your veterinarian and technician will also discuss how to prevent re-infection as initial infection does not provide immunity. It is important to make sure your home and yard are free of ticks to prevent re-infection. As it can be difficult to visually spot ticks, we can recommend several local companies that are experts in helping you remove well-hidden tick colonies.

Other tick-borne diseases such as Lyme disease and Rocky Mountain Spotted Fever, are carried by ticks that are not found in Arizona so the incidence of these diseases are currently thought to be rare, but follow the same clinical pattern as Ehrlichiosis. Please let your veterinarian know if your dog or cat frequently travels outside of Arizona or just outside of the Tucson Metro Region, as his or her disease risk profile will include diseases not normally found in our area.

Heartworm & other Mosquito-Borne Diseases

Arizona was once part of the states where heartworm disease was unheard of. Our dry climate was thought to be the natural barrier to large mosquito populations. Unfortunately, due to our very mobile society in the last two decades, and urban moisture zones, heartworm has gone from being an Eastern Seaboard and Deep South issue to a nationwide disease. According to the Companion Animal Parasite Council and the American Heartworm Society, heartworms and heartworm disease are here in Arizona and here to stay.

It is recommended that all dogs, indoor only, native born and even those who never travel, be on year-round heartworm preventative. For more information on Heartworms and Heartworm disease, please visit our Heartworm page.

There are other mosquito borne diseases in our area of health significance. Diseases such as West Nile Virus and St. Louis Encephalitis are of concern for our clients who are horse owners. Please visit the Arizona Department of Health Services’ Vector-Borne & Zoonotic Diseases webpage for more information at https://www.azdhs.gov/preparedness/epidemiology-disease-control/vector-borne-zoonotic-diseases/index.php

Rattlesnakes

There are 13 species of rattlesnakes in the Sonoran Desert and 8-9 species that make their home in the greater Tucson area.  Snakes are a vital part of the ecosystem as they are the primary hunters of pest species such as gophers, packrats and mice.  Snakes do not bite from aggression, but as a protective mechanism.  The majority of bites, to both people and dogs, are due to disrupting or startling the snake, or attempting to handle or move the snake.  The most common places for curious dogs to become envenomated are the muzzle or front paws. The most important thing to remember with dogs and rattlesnakes is that the size of the dog, not the snake, matters. The smaller the dog the more complications can arise from rattlesnake bites. Complications can also arise if your dog is on a non-steroidal anti-inflammatory such as Rimadyl or Aspirin.  Location of the bite is also a factor in predicting complications.

If your dog is bit, the most important thing you can do is to stay calm and keep your dog calm.  Then head to your nearest veterinary clinic.  Do not attempt to provide first aid home remedies or “wait it out”.  The longer between the bite and appropriate medical treatment means the higher the risk of complications.

The rule of thumb for snake activity is “If warm enough for a t-shirt, warm enough for a snake”.  Early spring and the cooler times of summer days are the most common times to encounter a snake. It is extremely unusual for any of our native wildlife to be moving about during the hottest parts of the day.  No matter what species of snake is in your path or yard, it is best to leave the snake alone and contact an expert to have it identified and moved to different location. We work closely with a number of humane removal experts who can also help you in making your yard and home unattractive to rattlesnakes and their prey. Keep in mind that rattlesnakes follow 2 things, food and water. If your yard is attractive to mice, then snakes will follow.

We do not offer the “Rattle Snake Vaccine” as there is no evidence that it is an effective or necessary vaccine and is universally unsupported by reptile veterinarians and veterinary colleges.

We do recommend “Rattlesnake avoidance” training for all dogs. We strongly urge our clients to use training centers and trainers who practice humane training for both the dog and the snake. Trainers who use snakes that have been “muzzled” or “defanged” will be unlikely to use humane techniques with your pet. We have included a few training centers who treated their snakes with as much respect and care as they treat your dog.

Toads

 Our local toad species are most active during and right after our summer rains.  The species of medical concern is the Sonoran Desert Toad (formerly known as the Colorado River Toad).  When frightened this toad secretes a toxin through the skin.  This toxin is then passed through the mucus membranes of the mouth when the pet bites or licks the toad.  As with rattlesnakes, the size of the dog and any current medications that the dog is on affects the severity of clinical symptoms.

The chemicals in the toad’s secretion affect the heart and nervous systems, if untreated these toxins cause heart rhythm irregularities, secondary hyperthermia, or continuous seizures leading to coma and death.  The goal of medical treatment is to control any seizure activity or heart irregularities. 

Within 30 minutes to 1 hour of contact with the toxin the first symptoms of toxicity appear.  These are:

  • Crying or pawing at the mouth

  • Increased salivation/ drooling

  • Seizures

  • Stiff or clumsy gait

  • Brick red gums and tongue

If your pet is not having seizures, rinse the mouth with copious amounts of water for 5 to 10 minutes.  Then go to your veterinarian where medical treatment can be started.

Heat

Temperature is another major concern for our pets.  Our summer days can easily reach 110ºF or higher with varying humidity levels depending on the month.  Sadly, every year there are reports of children and pets being left in cars unattended and suffering serious injury or death.  On a 72ºF day, the interior of a car in sunlight even with the windows open can reach 110ºF within 1 hour.  On an average Tucson summer day of 90ºF or more, within 10 minutes the interior temperature can reach over 120ºF and within 1 hour hit 200ºF.  Studies have shown that it DOES NOT help if the windows are open.  As our pets have a reduced ability to cool themselves, within minutes your dog’s body temperature has risen to dangerous levels. 

 This has become such a problem that it is now illegal in the state of Arizona to leave an animal in a vehicle. ARS 13-2910, subsection A, paragraph 7, states: “Intentionally, knowingly or recklessly leaves an animal unattended and confined in a motor vehicle and physical injury to or death of the animal is likely to result” is a “Class I misdemeanor”.  Our laws also allow a law enforcement agent to use “reasonable force” to release the animal from the vehicle, which can include breaking windows. Our laws also protect Good Samaritans who break or damage windows to get animals out of hot cars. Keep in mind that for most of our summer you can bake cookies on the dashboard of your car, we don’t want our pets to bake either.

Our local ordinances also do not allow you to leave your dog outside without adequate water and shade provided.  Keep in mind that the dog houses sold in pet stores are insulated to keep in heat.  These act as an oven and do not provide cooling shade that the law requires.  “Tie Outs” or tethering a dog to any object that does not allow it to move away from sun or waste is illegal statewide.  

Normal body temperature for dogs and cats is between 100ºF and 103ºF.  Symptoms of heat stroke are increased drooling, excessive panting, very red gums, respiratory distress, and muscle tremors.  Without veterinary treatment to lower internal body temperature, these symptoms can quickly progress to heart rhythm abnormalities, shock, seizures, coma, followed by respiratory and cardiac arrest.  Basic first aid is to wet the pet with cool, but not cold water, move the pet to a cool area and call your veterinarian.  If you find your dog having seizures, do not submerge the pet, but gently wrap it in a cold towel and head to your nearest veterinary clinic or animal emergency center. 

Burns to paw pads are another problem we frequently see due to road and sidewalk temperatures.  The test to see if the road is cool enough to walk or run with your dog is to put your hand on the asphalt (the black roadway) and count slowly to 20.  If you cannot keep your hand on the road for 20 seconds it is still too hot to take your dog walking.  We recommend limiting outdoor trips to early morning hours before the temperatures have risen and the surface has spent hours exposed to sunlight.  It is also recommended for new residents to slowly acclimate your dog to our temperatures, elevation and humidity levels. 

Important contact information

Lastly, we have included below a list of important numbers to have.  If you have any questions or would like information about any of the topics covered in this handout, please speak to one of our veterinarians or technicians. 

24 Hour Emergency and Specialty Hospitals           

  • Veterinary Specialty Center of Tucson
    520-765-9955
    4909 N. La Canada Dr (La Canada and River behind Walgreens)

  • Southern Arizona Veterinary Specialty & Emergency Center
    520-888-3177
    141 E. Ft Lowell Rd (between First Ave and Stone)
    7474 E. Broadway Blvd. (between Kolb Rd. and Pantano Rd.)

Other Resources

Rattlesnake Avoidance Training

  • Sublime Canine (520) 975-0878

  • Animal Magnetism (520) 440-5040

  • Humane Society of Southern Arizona (520) 327-6088

Disseminated

Lameness in one or more limbs/joints

Swelling in one or more limbs/joints

Swellings or lesions on the skin

Fever

Weight Loss

Reduced Appetite or Anorexia

Lethargy

Generalized pain when touched

Seizures or other neurological symptoms

Sub-clinical Ehrlichiosis

Spontaneous bleeding

Swollen lymph nodes

Swelling in limbs

Bleeding in eyes/sudden blindness

Reduced appetite

Fever

Weight loss

Lethargy

Pain in joints

Seizures