Canine Distemper | Diagnosis, Treatment & Prevention

        Canine Distemper | Diagnosis, Treatment & Prevention

 It is a polysystemic disease caused by canine distemper virus(CDV), an RNA virus. It is also called hard pad disease because in this disease the footpad of dog become hard and the animal shows the signs of lameness. Susceptible hosts for this disease are dogs, cat, badgers, skunks, seals, ferrets, and porpoises. This virus replicates in the lymphoid, nervous and epithelial tissues, shed by an animal in respiratory exudate, feces, saliva, urine and in the conjunctival exudate for up to the 60-90 days after the natural infection. Animal at any stage of his life is susceptible to this virus but puppies at the age of 3 to 6 months are highly susceptible and disease is common in this age group of animals.

Clinical signs:

By the 9 to 14 days of infection, the virus replicates in the respiratory, gastrointestinal and urogenital system of the animal and then the animal will start showing the signs of diseases. CNS infection also occurs in dogs with low immunity. Diphasic fever is the sign of CDV. In this fever the temperature of animal will rise up to the 103-104 F for 72-96hrs then become normal for 11-12 days and then again rise up to the presence of polysystemic disease. When animal recovers from the polysystemic disease, it is still shedding the virus in his body secretions especially in urine. On the basis of the clinical signs, this disease has different forms.

Pulmonary form:

In pulmonary form following signs showed by the animal.
Cough, yellow-greenish oculonasal discharge, tonsillar enlargement, increased bronchial sounds, crackles, and wheezes can be auscultated in a dog with bronchopneumonia.

Digestive Form:

In this form following signs are shown by the animal.
Anorexia, vomiting, diarrhea due to enteritis and abdominal pain. Blood may also come in diarrhea.

Ocular Form:

Mucopurulent ocular discharge, Anterior uveitis, Blindness, dilated pupil and inflammation of the retina and choroid.

Nervous Form:

Hyperesthesia, seizures, paresis (partial paralysis due to the nerve damage), and chorea myoclonus(uncontrolled movement of a muscle or a group of muscles; especially shoulder, hips, and face), chewing gum fits, nystagmus.
In older dogs depression, circling, head pressing and visual defects due to degeneration of the cerebral cortex.

Cutaneous Form:

Hyperkeratosis of nose and footpad, and pustular dermatitis.

Other signs:
Enamel hypoplasia found in dogs that were infected with CDV before the development of permanent dentition. Puppies that are infected transparently can be stillborn, aborted, or born with CNS disease.

Diagnosis:

1. Diagnosis is based on the clinical signs.
2. Hematological examination: Leukopenia and mild thrombocytopenia.
3. CSF antibody titer can be checked against the CDV. But take care in this method that the sample should not be contaminated with blood and should not be vaccinated. After attaining these precautionary measures if you still find antibody titer against CDV in CSF then the diagnosis is confirmed.
4. Rt-PCR 
5. Examination of histopathological examination. Intracytoplasmic inclusion bodies will be detected in lung, brain in gastric samples.

Treatment:

1. There is no specific treatment for canine distemper. But anti-distemper serum can be used at the dose rate of 1-5 ml/kg through IV, IM or SC route.
2. Anticonvulsant drugs like lardopa or pacitane can be used.
3. Use of antibiotic to avoid secondary bacterial infection.
4. Do supportive therapy with normal saline and lactated ringer solution.
5. Glucocorticoids are contraindicated in acute case but can be used in a chronic case.

Prevention & Control:

• Isolation of infected dog. Because the virus can live for approximately one hour in the infected animal secretions.
• Use a disinfectant to clean the area. Because this virus is susceptible to common disinfectants.
• Vaccination of healthy dogs.
• Measles vaccines also effective against CDV.

Zoonoses:

For the zoonotic point of view, the canine distemper is not a zoonotic disease.

Reference: Small Animal Internal Medicine 4th ed. by Richard W.Nelson.