Saving our Shadows: A Story of Determination in Canine Health Research

Authors:
Sree Rajeev, BVSc & AH, PhD, DACVM, DACVP
Professor of Infectious Diseases
Director of Bacteriology and Mycology Diagnostic Laboratory
Biomedical and Diagnostic Sciences
University of Tennessee, College of Veterinary Medicine
And
MalavikaRajeev, PhD, MS
Fellow at the Centers for Disease Control and Prevention


The loss of our beloved Tulip was devastating. She was our first family dog in the United States, a Norwegian Elkhound mix with the gentlest soul. She was only nine years old when she died from an acute bleeding disorder, the cause of which was never determined.

Sumi

A few months after Tulip passed, a squirmy, beautiful Australian Cattle Dog mix came into the clinic where my husband practiced in a small town in rural Georgia. She had been found wandering the country roads by animal control. She came into his clinic for a wellness check and tested positive for heartworms. In the deep, rural south, where the shelters were constantly full, that usually meant the end of the road for a pup. This pup was so adorable that the folks at the clinic couldn’t bear to give up on her.

My husband sent a picture of the puppy to my daughter, saying something along the lines of how she had Tulip’s eyes. A couple hours later she was home with us and fit right in with our other two pups, the dachshund “Ramu” and the quirky beagle “Burlap.” We named her Sumi, a common Indian nickname, that means something along the lines of a friendly, good hearted woman.  We started her on the long road of heartworm treatment, keeping her confined and managing her activity for months. She was also learning the ropes of being an indoor dog—cabinets and kitchen islands befuddled her for the first few weeks. She took a while to warm up to most people, but her person was my daughter who had brought her home that first day, and she would follow her around like a shadow. When my daughter left the house for college, Sumi became my shadow.

Dr. Sree Rajeev and Dr. Malavika Rajeev with Ramu, Burlap, and Sumi

We were truly empty nesters then and I was beginning to feel pretty restless when a recruiter from the Ross University School of Veterinary Medicine (RUSVM) contacted me about a position. I talked to her politely, using the excuse of my husband’s job as a reason for saying no. She ensured me that they had opportunities for a practicing clinician as well. In some turn of events, we ended up taking the deal, leaving my faculty job at the University of Georgia and moving to the tiny Caribbean nation of St. Kitt’s and Nevis, all three dogs in tow. We drove eight hours to Miami and flew to the Caribbean. Although our anxiety was through the roof while flying the dogs in cargo, we were relieved to see the safe landing and our resilient pups.

At first, life on the island took some adjusting to, but it was also one of the most beautiful places in the world. The forest and volcanic mountain rose up in the middle and the views were spectacular. Wherever you were, you had about a 90% chance of seeing the ocean. And the dogs enjoyed their life chasing monkeys and chickens on the island. I taught veterinary students clinical microbiology and also pursued my research in leptospirosis. The island was a perfect natural laboratory for this research with its plethora of disease hosts. There were innumerable questions to ask in this domain, but Sumi led to another line of questioning in my research track.

One day when we woke up and checked on the dogs. Sumi was lethargic and uninterested in food. When Tulip had gotten sick before, one of the most concerning signs was her paper white gums. Sumi’s were exactly the same. We rushed her to the clinic at Ross where my husband was practicing. When animals from the island showed up at the clinic with these symptoms, tickborne diseases such as Ehrlichia canis and Anaplasma platys infections were at the top of the differential diagnosis list. We examined her blood sample and her platelets were loaded with little round balls of bacteria, a typical feature of Anaplasma platys infection. A tick-borne disease, it can cause severe internal bleeding, and without prompt diagnosis and treatment, it can be a fatal disease. If Sumi had been in the US, she likely would not have been diagnosed as quickly, but the experience of the clinicians and technicians on St. Kitt’s saved her. Anaplasma was endemic on the island, and they commonly saw dogs with this infection. We treated Sumi with a course of doxycycline, and she was back on her feet in a few days.

Part of me couldn’t let it go however. Maybe because Tulip’s illness ended with no clear answer, I felt that this time I could do more. I did confirmatory diagnostics in my lab using a molecular test (PCR) - Anaplasma platys grows inside the cells and cannot be cultured in the laboratory. The RUSVM research center director, Dr. Sean Callanan, was kind enough to provide funding for me to pursue this research further. With a small seed grant, we pursued a metagenomic approach to sequence everything in Sumi’s blood. My bioinformatic colleague from INDICASAT Panama, Dr. Alejandro Llanes, was reluctant to approach the analysis due to the complexity of extracting the genome from that type of data (much like looking for a needle in the haystack). But with my doggedness, he was able to get the full DNA sequence of the pathogen from Sumi’s blood and generated the first ever reference genome for A. platys.

We found that there were many similarities between the A. platys genome and that of Ehrlichia canis - a pathogen that causes another debilitating disease in dogs transmitted through the same tick vector. We needed more funding to put this genome to work, and my dream was to start developing common vaccine candidates for these devastating canine diseases. But the challenge was funding. These pathogens are specific to dogs, which means the people willing to fund research on them are limited to those who are in the business of protecting our pups. Federal agencies are not interested in pathogens that only affect companion animals.

The AKC Canine Health Foundation’s (CHF) call for vector-borne disease research proposals was my main hope, and fortunately we were awarded a grant to further pursue this research which could save the lives of many of our most faithful friends (CHF Grant 02981: Genome-wide Identification and Characterization of Peptide Epitopes from Ehrlichia canis and Anaplasma platys with Potential to be Used as Vaccine Candidates). Thanks to CHF funding, we have several vaccine and diagnostic candidates in the works, and we are ever closer to producing ways to prevent and treat these tick-borne infections in dogs.

Sumi, Ramu, and Burlap came back to the mainland when I moved back. Burlap left us at the ripe old age of 17 years, and we had to let dear Ramu go at 15 years of age. Sumi is now a hale 14 year old pup, outlasting both her brothers and going strong. She has her senior dog moments, but still plays with her squeaky toys almost every day and gets a special portion of chicken and rice for dinner.

I often wonder what would have happened to her if she hadn’t fallen in with a family of veterinarians and a mom with a microscope. And also, I think of all the dogs out there, beloved members of our families, that may not have access to the diagnostics and treatments that could save their lives. I hope that the research I do will make an impact in this realm. I am grateful for nonprofit organizations such as the AKC Canine Health Foundation, for supporting research to help our shadows live their lives to the fullest.

Learn more about CHF-funded tick-borne disease research at akcchf.org/ticks.