Valley Fever in Dogs: Causes, Symptoms and Diagnosis of Valley Fever in Dogs MiDOG Animal Diagnostics

June 14, 2024

Valley Fever, also known as coccidioidomycosis, is an emerging concern for veterinarians in the United States, particularly in regions with arid climates such as California.

Current Status of Valley Fever in Dogs

Valley Fever is caused by the soil-dwelling fungi Coccidioides immitis and Coccidioides posadasii. These pathogens are endemic to the southwestern United States, including:

California
Arizona
Nevada
New Mexico
Texas
and Utah

The incidence of Valley Fever in dogs has been rising, paralleling the increase in human cases. Factors contributing to this trend include population growth in endemic areas, increased recreational activities in desert regions, and climate change influencing the distribution and virulence of the fungi.

In California, the Central Valley and surrounding regions are hotspots for Valley Fever. The disease poses a significant health risk to dogs living in or traveling through these areas. Recent studies indicate that approximately 30-40% of dogs residing in endemic regions are exposed to the fungi at some point in their lives, with a subset developing clinical disease.

valley fever coccidioides fungus

Clinical Presentation of Valley Fever in Dogs

Dogs infected with Valley Fever can present with a variety of clinical signs, which can be acute or chronic. The severity and type of symptoms depend on the extent of fungal dissemination and the organs affected. Here are the common clinical presentations in canine patients:

Respiratory Symptoms: Coughing, labored breathing, nasal discharge, and lethargy.
Musculoskeletal Symptoms: Lameness, swelling of limbs, bone pain, and reluctance to move.
Cutaneous Symptoms: Skin lesions, draining tracts, and non-healing sores.
Neurological Symptoms: Seizures, ataxia, and changes in behavior or consciousness.
General Symptoms: Fever, weight loss, anorexia, and generalized weakness.

It is important for veterinarians to consider Valley Fever in the differential diagnosis when dogs from endemic areas present with these non-specific signs.

Pathogens Causing Valley Fever in Dogs

Valley Fever is caused by two primary pathogens:

Coccidioides immitis: Predominantly found in California’s San Joaquin Valley and surrounding areas.
Coccidioides posadasii: More commonly found in other parts of the southwestern United States, including Arizona.

Both species have similar pathogenicity and clinical manifestations in dogs. The fungi exist in the soil as arthroconidia, which are inhaled by the host. Once in the lungs, the arthroconidia transform into spherules that contain endospores, leading to local infection and potential dissemination to other organs.

Diagnostic Tools for Valley Fever

Accurate and timely diagnosis of Valley Fever in dogs is crucial for effective treatment and management. Several diagnostic tools are available to veterinarians:

Serology: Detection of antibodies against Coccidioides spp. in the blood using tests such as enzyme-linked immunosorbent assay (ELISA), immunodiffusion (ID), and complement fixation (CF). These tests are widely used but can have limitations in sensitivity and specificity.
Cytology and Histopathology: Examination of tissue samples from affected organs (e.g., lymph nodes, bone, skin) to identify spherules of Coccidioides spp. This method is direct but may require invasive procedures to obtain samples.
Culture: Isolation of Coccidioides spp. from clinical specimens (e.g., respiratory secretions, tissue biopsies). Culture is definitive but slow and poses a biohazard risk to laboratory personnel.
Polymerase Chain Reaction (PCR): Detection of fungal DNA in clinical samples. PCR offers rapid results and high specificity but may not always be available in all veterinary laboratories.

valley fever diagnosis

Next-Generation Sequencing as a Diagnostic Tool

Next-generation sequencing (NGS) has emerged as a powerful diagnostic tool with higher sensitivity and specificity for detecting Valley Fever compared to traditional methods. NGS allows for the comprehensive analysis of genetic material in clinical samples, enabling the identification of Coccidioides spp. even in low-abundance infections.

Advantages of NGS in Diagnosing Valley Fever

Higher Sensitivity: NGS can detect Coccidioides DNA at very low levels, increasing the likelihood of diagnosing infections that might be missed by serology or PCR.
Higher Specificity: By analyzing the genetic material, NGS can accurately distinguish between different pathogens and provide definitive identification of Coccidioides spp.
Comprehensive Detection: NGS can simultaneously identify multiple pathogens, which is particularly useful in cases where co-infections are suspected.
Non-Invasive Sampling: NGS can be performed on various sample types, including blood, respiratory secretions, and tissue biopsies, reducing the need for invasive procedures.

Implementation of NGS in Veterinary Practice

The use of NGS in veterinary diagnostics is gaining traction, with several commercial laboratories offering NGS-based testing for Valley Fever and other infectious diseases. Veterinarians should consider the following when implementing NGS:

Sample Collection and Handling: Proper collection and preservation of samples are crucial for accurate NGS results. By using the MiDOG collection kits, the samples are preserved at room temperature and the pathogens are effectively lysed upon contact for save handling of the sample for all personnel involved.
Turnaround Time: While NGS provides comprehensive results, with a turnaround time of just 2-3 days by the MiDOG laboratory for requiring rapid diagnosis.

Valley Fever in Dogs: Conclusion

Valley Fever remains a significant health concern for dogs in the USA, particularly in endemic regions like California. Veterinarians play a crucial role in the early detection and management of this disease. Understanding the clinical presentation, causative pathogens, and available diagnostic tools is essential for providing optimal care.

Next-generation sequencing testing, as offered in the All-in-One Test by MiDOG Animal Diagnostics, represents a significant advancement in the diagnosis of Valley Fever, offering higher sensitivity and specificity compared to traditional methods. By incorporating NGS into diagnostic protocols, veterinarians can improve the accuracy of diagnoses and enhance the overall quality of care for their patients.

For further reading and up-to-date information on Valley Fever in dogs, refer to the following sources:

Shubitz, L.F., & Dial, S.M. (2021). Coccidioidomycosis: A Review of Recent Advances. Journal of Fungi, 7(5), 378. Link
Thompson, G.R., & Wiederhold, N.P. (2022). Coccidioidomycosis: A Changing Epidemiology. Clinical Microbiology Reviews, 35(3), e00015-22. Link
Galgiani, J.N., et al. (2020). Valley Fever (Coccidioidomycosis) in Dogs: An Overview for Veterinarians. Veterinary Clinics of North America: Small Animal Practice, 50(2), 341-358. Link

By staying informed and utilizing advanced diagnostic tools, veterinarians can effectively combat Valley Fever and ensure the well-being of their canine patients.

Categories: Dogs, Next-Gen DNA Sequencing Technology, Pet Health, Safety and Wellness, Respiratory Infection

Validated by Veterinarians

“Clients expect their veterinarians to stay up to date on all matters that affect the health and well being of their non-human family members. The current technique that we have used to determine the presence and antibiotic sensitivity of organisms causing disease in our pets is over a century old.

With the emergence of dangerous antibacterial resistance, it is critical that veterinarians are able to offer laser focused diagnostics and treatment. MiDog enables us to offer care that exceeds the typical standard of care.”

Bernadine Cruz, DVM, Laguna Hills Animal Hospital Laguna Woods, CA

“I love the absolute abundance and comparing the fungal with bacterial infection. I do not worry as much about getting a false negative urinary infection reading as I do with traditional urine cultures. Several times the same urine would culture negative but MiDOG would detect pathogens.”

Michael Morgan, DVMQuail Animal Hospital, Tustin, CA

“The MiDOG All-in-One Test is amazing, I would use it instead of culture and sensitivity. Such rapid and detailed results, I will reach for MiDOG before culture next time!

Thank you very much MiDOG, for sharing the opportunity to try your technology.”

Martha Smith-Blackmore, DVM, President of Forensic Veterinary Investigations, LLC – Boston, MA

“The MiDOG All-in-One Microbial Test is our new gold standard of pathogen identification. The results are so accurate and valuable – especially with assessing both bacterial and fungal infections with the same sample.

Thank you MiDOG!”

Kathy Wentworth, DVM, Diplomate ABVP Canine and Feline Practice – PetPoint Medical Center, Irvine, CA

“The MiDOG staff was extremely helpful and supportive.”

Cathy Curtis, DVM – London, UK

“I have had great results using the MiDOG® Test. Compared to traditional culture tests, I am better able to target the treatment for dogs because the MiDOG® Test is so sensitive that it identifies all pathogens including bacteria and fungi, as well as antibiotic sensitivity.

The cost and turnaround time are about the same as a culture test, but I get much more data. The test has great performance and I believe the NGS technology will be a game changer for veterinarians treating dogs with lesions or other infections.”

Michael Kavanagh, DVM, Practice owner – Saddleback Animal Hospital, Tustin, CA

“It’s helpful to have an NGS spectrum because it gives you a broader insight of what’s happening and what might be going on.”

Richard Harvey BVSc DVD DipECVD PhD FRSB FRCVS – European Specialist in Veterinary Dermatology – Head of Dermatology, Willows Veterinary Centre & Referral Service – Solihull, England UK

“I have been using MiDog for over 4 years now and exclusively as my test of choice for all cultures for 3 years. It is so great to submit a culture and feel confident there will be a result when it comes back, especially for urine cultures. The reports were intimidating at first because they contain so much information. After the first few, I am now quickly able to glance over it and pick out the highlights. I can then come back later and pour over all the details. I have been extremely pleased with my patients’ results using the test as well. I don’t envision ever going back to traditional culture and susceptibilities again.”

Brian M. Urmson, DVM, Columbiana Veterinary Associates

“As an exotic veterinarian, there are numerous tests we have to consider to check specific bacterial and fungal organisms based on the species. MiDOG eliminates the need for many of these separate samples and provides definitive results quickly to help us treat our patients more efficiently and effectively. The lab is wonderful to work with and has never rejected our samples- they even processed a lizard toe we amputated and determined the cause of skin infection.”

Dr. Melissa Giese, Chicago Exotics Animal Hospital

“MiDOG’s diagnostic approach offers the unique ability to identify pathogens that evade traditional culture and sensitivity testing. I have found that adding a molecular based testing approach in the form of Next Generation Sequencing (NGS) from MiDOG to my routine diagnostic cultures can be extremely helpful in the identification and diagnosis of uncommon pathogens in veterinary medicine.”

Dr. Wayne Rosenkrantz, Animal Dermatology Clinic – Tustin

“She [Dr. Krumbeck] really did a great job of making complicated concepts accessible and demonstrating the value of your services. I’m really looking forward to working with MiDOG on my research project!”

Dr. Yaicha Peters, Animal Dermatology Clinic – San Diego

“As a proud collaborator with MiDOG, I deeply appreciate their dedication to fostering partnerships between industry and veterinary experts. Their commitment to enhancing diagnostic quality for veterinarians is commendable. In my experience, their support has been invaluable, earning them a ‘Double A+, Triple Star’ rating. Their assistance has been faultless, contributing significantly to the success of my projects and studies. I eagerly anticipate our continued collaboration.”

Dr. Richard Harvey, BVSc DVD DipECVD PhD FRSB FRCVS; European Specialist in Veterinary Dermatology

“We’re seeing that, if we prescribe too many antibiotics or they’re taken too frequently, animals are developing inappropriate or pathogenic strains of bacteria. We’re also seeing that our antibiotics are just not working against them anymore… It’s a good example of why we need better diagnostic testing, like MiDOG, so that we’re selecting the correct antibiotic every time our patients have an infection.”

Dr. Alissa Rexo, DVM, CVA, DACVD, Mid-Atlantic Veterinary Dermatology

“The NGS technique as offered by MiDOG is wonderful because pathogens like Melissococcus plutonius, for example, are difficult to grow and keep alive in the laboratory. A standard laboratory cannot truly examine or even properly diagnose this pathogen in bee hives at this time. But with NGS, we can reliably diagnose it.”

Dr. Joerg Mayer, Entomologist and Microbiologist at the University of Georgia

“For me, as a clinician and as a researcher, I see the immense value in the product [the All-in-One Test]. I have had great success using MiDOG clinically, including identifying Mycoplasma in a 24 year old pigeon, a Nannizziopsis spp in a ball python from a large pet distributor, Mycoplasma and Fusobacterium necrophorum co-infection in a peacock, and to identify an abnormal gut GI in a technician’s dog that tested negative for everything else (but we were able to establish what was abnormal, and work toward fixing it).”

Dr. Jeremy Rayl – Veterinarian, Block House Creek Animal Hospital, Cedar Park, Texas