Specific diseases in Shibas

The Shiba is considered to be a robust dog not being especially susceptible for diseases. The few typical disorders of this breed include hip dysplasia and patella luxation. Apart from these, reports from breeders and owners on incidences of allergy and epilepsy have recently increased, however veterinarians have not yet provided any up-to-date scientific proof. Finally those diseases already described in detail on this web site are to be mentioned: the metabolic disease GM1 gangliosidosis, the bleeding disorder haemophilia A and the glaucoma.

Even though the Shiba in general is a healthy dog, it would not be right to convey the impression that the Shiba is – so to speak – "immune" against diseases. In fact, as in any other breed, there is always the possibility that new and as yet, for Shibas, unknown disorders could appear. In Japan where the Shiba is often the subject of veterinary medical investigations several specific diseases have been diagnosed and described. We have browsed English-language publications from Japanese universities and clinics as well as those from some American and British clinics and would like to introduce briefly the case reports we have found.

The reported diseases range from severe and incurable to relatively slight, curable disorders. The disorders pertained to internal organs (kidney, heart, intestine), two different glands, blood cells and the skin. In one specific case it would be wrong to speak of a disease in the strict sense, rather it was a matter of genetic change (polymorphism) in a larger number of Shibas. The diseases affected Shibas of all ages.

• Oesophageal stricture (→ oesophagus)

E. Fox, K. Lee, C. R. Lamb, J. Rest, S. J. Baines, D. Brockman: Congenital oesophageal stricture in a Japanese shiba inu, The Journal of Small Animal Practice 2007 [in print].

An oesophageal stricture is a gradual narrowing of the oesophagus, which can lead to swallowing difficulties. The strictures are caused by scar tissue that builds up in the oesophagus. Symptoms are difficulties with swallowing, regurgitation of food and weight loss.

An 11-week-old, female, Japanese shiba inu, weighing 1.3 kg, was presented with a history of intermittent regurgitation since birth. An oesophagram showed a partial obstruction of the caudal cervical oesophagus associated with a narrow, transverse tissue band. Following surgical resection, the regurgitation resolved and the dog attained a normal bodyweight. Histological examination revealed focally hyperplastic epithelium with dense fibrous underlying connective tissue forming the band. The diagnosis was a congenital oesophageal stricture.

Therapy: Surgical treatment and dilation of the oesophagus by the use of several methods.

• Systemic candidiasis (→ whole body – fungal infection)

Kuwamura M., Ide M., Yamate J., Shiraishi Y., Kotani T.: Systemic candidiasis in a dog, developing spondylitis, Journal of Veterinary Medical Science 68 (2006), pp. 1117-1119.

Candidiasis is a fungal infection (yeast) of any of the Candida species, of which Candida albicans is the most common. Systemic (affecting the body as a whole) candidiases predominantly end up fatally. Spondylitis is an inflammation of the vertebrae.

A 4-year-old male Shiba dog was presented with pain of an undetermined origin and hypersensitivity to touch. Seven days later, the dog developed ataxia (lack of coordination) and knuckling of both hind-legs. The dog died 20 days after presentation. Postmortem examination revealed a granulomatous inflammation in the body of thoracic vertebra, including fungal organisms that were immunohistochemically positive for Candida albicans. Similar granulomatous lesions were observed in the systemic lymph nodes, kidneys, pancreas, spleen, prostate gland, thyroid glands and heart. This case was diagnosed as systemic candidiasis with spondylitis.

Therapy: candidiasis is treated with antimycotics (antifungal agents), spondylitis is treated conservatively with antibiotic chemotherapy as well as surgically.

• Histoplasmosis (→ skin – fungal infection)

Ueda Y., Sano A., Tamura M., Inomata T., Kamei K., Yokoyama K., Kishi F., Ito J., Mikami Y., Miyaji M., Nishimura K.: Diagnosis of histoplasmosis by detection of the internal transcribed spacer region of fungal rRNA gene from a paraffin-embedded skin sample from a dog in Japan, Veterinary Microbiology 94 (2003), pp. 219-224.

Histoplasmosis is an infectious disease caused by inhaling the spores of a mould called Histoplasma capsulatum. This fungus that exists in several variants can affect skin, internal organs and bones entailing severe tissue lesions.

In this particular case a 5-year-old female Shiba was affected, suffering from ulcers on the skin probably caused by the parasitic fungus Histoplasma capsulatum var. farciminosum.

Remarkably histoplasmosis in Japanese dogs is restricted to ulcers on the skin or gums (gingiva) as opposed to affected dogs in North America which tend to have pulmonary or gastrointestinal lesions. Therapy: surgical excision.

• Glomerulocystic kidney disease (→ kidneys)

Takahashi M., Morita T., Sawada M., Uemura T., Haruna A., Shimada A.: Glomerulocystic kidney in a domestic dog, Journal of Comparative Pathology 133 (2005), pp. 205-208.

The glomerulocystic kidney disease (GCKD) develops due to cystic dilatation inside the kidney, more precisely in the renal corpuscles or glomeruli (literally "little balls of yarn"). These glomeruli are part of the nephron, a subunit of the kidney. Due to the cysts, the renal functions are strongly impaired. It is a rare, heritable disorder, probably dominantly transmitted.

In this particular case a 5-year-old female Shiba was affected and died from chronic renal failure together with convulsions, vomiting and diarrhoea. Therapy: none in dogs until now.

• Nephrogenic diabetes insipidus (→ kidneys)

Takemura N.: Successful long-term treatment of congenital nephrogenic diabetes insipidus in a dog, The Journal of Small Animal Practice 39 (1998), pp. 592-594.

The nephrogenic diabetes insipidus (NDI) is a rare hereditary disease which is X chromosome-linked and transmitted recessively. It is not related to diabetes mellitus ("sugar diabetes"); in fact it is a disease in which the kidneys are unable to concentrate fluid in the organism sufficiently and consequently large volumes of urine have to be excreted.

In this particular case a 2-year-old male Shiba was affected, suffering from polyuria (excessive urination) and polydipsia (excessive thirst). The disease was treated successfully with plentiful access to drinking water and a low sodium diet.

• Lymphosarcoma (→ blood cells, kidneys)

Zhao D., Yamaguchi R., Tateyama S., Yamazaki Y., Ogawa H.: Bilateral renal lymphosarcoma in a dog, The Journal of Veterinary Medical Science 55 (1993), pp. 657-659.

Lymphosarcoma is a malignant proliferation of lymphocytes (white blood cells) in certain internal organs. It is one of the most common tumours diagnosed in dogs.

In this particular case a 3-year-old female Shiba was affected, suffering from vomiting, diarrhoea, oliguria (decreased urine output) and abdominal enlargement, associated with hypoglycaemia (low blood sugar). A lymphosarcoma in both kidneys with metastases in several internal organs was diagnosed. Therapy: chemotherapy is possible, with the chance of healing.

• Microcytosis (→ blood cells)

Gookin J. L., Bunch S. E., Rush L. J., Grindem C. B.: Evaluation of microcytosis in 18 Shibas, Journal of the American Veterinary Medical Association 212 (1998), pp. 1258-1259.

Microcytosis is a blood disorder characterised by the presence of microcytes (abnormally small red blood cells) in the blood. It is a common disorder in Asian dog breeds (Akita, Shiba Inu, Chow Chow). The most common cause of microcytosis is iron deficiency, often to be found in growing animals or in consequence of blood loss.

In a study to determine whether microcytosis is a typical finding in Shibas blood and serum samples from 18 dogs were obtained for automated hematologic analyses. Microcytosis was identified in 12 of 18 Shibas. Males and females were affected equally. The results imply that microcytosis is a typical finding in Shibas. A hereditary basis is assumed.

Treatment: parenteral iron supplementation should be initiated and followed by oral iron supplementation for 1 to 2 months or until clinical signs of anaemia have resolved.

• Polymorphism in erythrocytes (→ blood cells)

Fujise H., Hishiyama N., Ochiai H.: Heredity of red blood cells with high K and low glutathione (HK/LG) and high K and high glutathione (HK/HG) in a family of Japanese Shiba Dogs, Experimental Animals 46 (1997), pp. 41-46.

In a long-term study the blood cells of more than 80 Shibas were investigated. As a result, in more than half of the dogs increased potassium values and reduced sodium values in the erythrocytes (red blood cells) have been ascertained.

Normally such mutated values are a consequence of a disorder, often caused by renal problems. In the Japanese Shibas however no obvious effect on fitness was observed, thus suggesting a genetic change (polymorphism) as the cause. The inheritance was recessive.

• Partial atrioventricular septal defect (→ heart)

Yoshihisa Yamane: Surgical Correction of a Partial Atrioventricular Septal Defect With a Ventricular Septal Defect in a Dog, Journal of the American Animal Hospital Association 41 (2005), pp. 137-143.

A 2-month-old, 2.4-kg, male Shiba Inu was referred for evaluation of a heart murmur and suspicion of congenital heart disease. The heart murmur was identified during physical examination prior to routine vaccination. The dog was otherwise normal and appeared to be healthy. Upon auscultation, a grade III/VI holosystolic murmur was found and was loudest over the left cardiac apex. The sinus heart rate was 180 beats per minute. The physical examination was otherwise normal. Complete blood count and serum biochemical tests were within reference ranges.

A partial atrioventricular septal defect was diagnosed on echocardiography and angiography. Surgical repair was conducted under extracorporeal circulation. The atrial septal defect (ASD) and ventricular septal defect (VSD) were repaired completely, and hemodynamic improvement was achieved, although the mitral valve malformation could not be completely repaired. The dog was clinically normal 1 year after surgery.

• Cor triatriatum dexter (→ heart)

Tanaka R., Hoshi K., Shimizu M., Hirao H., Akiyama M., Kobayashi M., Machida N., Maruo K., Yamane Y.: Surgical correction of cor triatriatum dexter in a dog under extracorporeal circulation, The Journal of Small Animal Practice 44 (2003), pp. 370-373.

The right and the left side of the heart respectively is made up of a lower chamber (ventricle) and an upper chamber (atrium). The rare, congenital disease cor triatriatum dexter is a cardiac defect in which the right atrium is partitioned into two compartments, effectively creating a triatrial heart.

In this particular case a 14-month-old male Shiba was suffering from strong abdominal distension due to fluid (ascites or abdominal dropsy). The cardiac defect cor triatriatum dexter was diagnosed as the cause. The two-part atrium on the right side of the heart has been corrected successfully by surgical operation. A heart-lung machine maintained the vital functions during the operation. This new therapy is very promising and offers an excellent prognosis.

• Thymoma (→ thymus gland)

Fukuoka A., Nakayama H., Nakayama Y., Yasoshima A., Uetsuka K., Fujino Y., Tsujimoto H., Doi K.: Thymoma in a dog with a part of granular cell proliferation and concurrent lymphoma cells, The Journal of Veterinary Medical Science 66 (2004), pp. 713-715.

The thymus gland is a little organ which lies underneath the top of the breast bone. It ensures that there are white blood cells (lymphocytes) to fight off infections. A thymoma is a tumour starting from the thymus. There is a distinction between benign and malignant types. The latter are called malignant thymoma or thymic carcinoma. Most of the thymic tumours are benign, approximately one third are malignant.

In this particular case a 12-year-old male Shiba was affected, suffering from anaemia, respiratory failure and swelling of the lymph nodes. After its death thymoma was diagnosed as the cause. Therapy: chemotherapy, prognosis depends on the severity.

• Pituitary chromophobe carcinoma (→ hypophysis/pituitary gland)

Sato J., Sato R., Kinai M., Tomizawa N., Osawa T., Nakada K., Yano A., Goryo M., Naito Y.: Pituitary chromophobe carcinoma with a low level of serum gonadotropin and an aspermatogenesis in a dog, The Journal of Veterinary Medical Science 63 (2001), pp. 183-185.

The hypophysis or pituitary gland lies at the base of the so-called diencephalon which is part of the forebrain and is located in the middle of the head above the midbrain. It is the most important ductless gland directing the activities of the other bodies' ductless glands. The pituitary carcinoma is a malignant tumour in the hypophysis. It is a rare type of brain tumour affecting the organism in different ways.

In this particular case a 5-year-old male Shiba was affected, showing neurological features (eating disorder (anorexia), lethargy, aimless barking and irritability to sounds and touches). A computed tomography disclosed a larger lesion in the diencephalon and midbrain due to a chromophobe pituitary carcinoma (chromophobe means that the cells cannot be stained for tests). The dog had to be put down. Therapy: surgical excision, if possible.

• Worm attack (→ small intestine)

Kugi G.: A new dipylipid cestode, Dipylidium oitaense, from a Shiba dog, Canis familiaris, Kiseichugaku Zasshi (Japanese Journal of Parasitology), vol. 38, no. 5 (1989), pp. 271-275.

Cestodes are any of various parasitic flatworms of the class Cestoda, including the tapeworms. Both dogs and cats are susceptible to infection with cestodes following ingestion of infected fleas or, more rarely, lice. Cestodes are found in the small intestine. Tapeworms can reach 4 to 6 inches in length within the intestine. It is the last segments of the worm that are released and can be seen in the stool or attached to the fur under the tail.

In the present case, two cestode specimens were obtained from the small intestine of a 3-month-old Shiba dog. The species belonged to the genus Dipylidium Leuckart, 1863, which contains seven species from carnivorous mammals. The found species differed from the seven known species in some physical characteristics. Treatment: anti-worm drugs as praziquantel, epsiprantel, and fenbendazole.

© Holger Funk 2007

Also published in Shiba World 2/2007