Jack Terriers Health
Jack Russell Terriers, due to their history as hunting dogs, are more susceptible to contracting skunk toxic shock syndrome.
A 2022 study on dog life expectancy in the UK, based on veterinary data, revealed that Jack Russell Terriers have an average lifespan of 12 years and 9 months—longer than any other breed in the study, including crossbreeds. A 2024 UK study extended these findings, documenting an average life expectancy of 13.3 years, compared to 12 years for crossbreeds and 12.7 years for purebreds overall. However, a 2024 Italian study reported a shorter life expectancy for the breed, averaging 8 years, compared to 10 years across all breeds studied.
Dermatological Conditions
Black hair follicular dysplasia is a rare condition that affects only the black hairs of bi-colored or tri-colored dogs. Jack Russell Terriers are among the breeds prone to this disorder, which can also occur in various other breeds, including mixed-breed dogs (mongrels).
A distinct form of ichthyosis, identified in specific Jack Russell Terrier families, has been noted for its severity compared to other types of the condition. Clinical and histopathological evaluations have linked this disorder to a mutation in the TGM1 gene.
Eye Disorders
Primary lens luxation is a hereditary condition commonly seen in Jack Russell Terriers and other breeds. Research has identified a mutation in the ADAMTS17 gene as the cause of this disorder.
Blood Disorders
The Jack Russell Terrier is prone to severe combined immunodeficiency (SCID), a genetic condition that impairs the immune system’s ability to fight infections. This autosomal recessive disorder often leads to death from infections within the first few months of life. Fortunately, the allele responsible for SCID occurs in less than 1.1% of Jack Russell Terriers, and genetic testing is available to detect carriers.
Musculoskeletal Conditions
Patellar luxation, a hereditary knee disorder, is common in Jack Russell Terriers. This condition causes the kneecap to dislocate from its normal groove, leading to temporary lameness, which resolves when the kneecap returns to its position. In severe cases, complications such as arthritis or torn ligaments may occur, and surgery might be required.
Jack Russell Terriers may also suffer from Legg-Calvé-Perthes disease, a condition where the femoral head deteriorates due to disrupted blood flow. This results in lameness, muscle atrophy, and joint pain, typically manifesting between 6 to 12 months of age. Other terrier breeds, such as the Border Terrier, Lakeland Terrier, and Soft-Coated Wheaten Terrier, are also affected by this disease.
Neurological Conditions
An inherited form of ataxia has been documented in Jack Russell Terriers for over 50 years. This condition is often accompanied by myokymia (muscle twitching) and seizures. A 2014 study identified a mutation in the KCNJ10 gene as the cause, which also affects closely related breeds like the Parson Russell Terrier and Russell Terrier.
Heredity and Health
There's no such things as a dog ---- Purebred or mixed ----- that doesn't carry some recessive deleterious genes in its makeup. These usually cause no problems, even for generations, until by chance, a mating occurs between two dogs carrying the same deleterious gene. The smaller the gene pool from which a breed originated, the more likely such a chance meeting will happen, because it's inevitable that some of the founding ancestors of the breed would carry and pass on its particular detrimental genes.
Despite the historically open criteria for recognition as a Jack Russell Terrier, the breed still has a limited gene pool that descends from relatively few ancestral foundation dogs.
Careless breeding increases the incidence of hereditary problems, but even carefully bred dogs can be affected.
Jack Russell Terriers are extremely healthy compared to other pure breeds, but even they carry a hereditary burden that includes several minor ones.