(Hard pad Disease/Canine Influenza/Carres disease) Highly contagious disease mainly affecting the young pups (3-6 months) manifested by diphasic fever, acute coryza, later bronchitis, catarrhal pneumonia, severe gastroenteritis nervous symptoms and frequent cutaneous eruptions. This was the major pathogen in dogs before the development of vaccination. First vaccination against CD was developed by an Italian scientist Puntoni in 1923-1924. Apart from dog; wolves, foxes, coyotes, ferrets, raccoons, minks, weasels and dingoes suffer with the disease. Animals of Felidae are not susceptible. Henri Carre, a French Veterinarian suggested the viral etiology of the disease. Laidlaw and Dunkin in 1926 confirmed the viral etiology of the disease. Virus belongs to Paramyxo virus. Virus is closely related to measles and Rinderpest virus. It will be destroyed if kept above 0˚C. It is inactivated by ether, 0.1% formalin and 1% Lysol. Virus can be adapted to grow in unweaned mice, baby hamsters and rabbits. Virus can be adapted to grow in chicken embryo or cell cultures of dog kidney/chicken embryo fibroblast cultures. It can produce IN/IC inclusion bodies. Transmission: Air borne disease. Indirect transmission is also possible through contaminated food and water. All secretions and excretions of the animal contain virus. Pathogenesis and Clinical symptoms: After entry the virus affect the epithelial cells of respiratory and alimentary tract. From there virus enters the tonsils and lymphatic system. Then primary viraemia starts and temperature may rise up to 104˚F. Some dogs may develop antibodies and recover from the disease within 1-2 weeks. Lymphopaenia is a distinct feature. If 2˚ bacterial infection occurs, then there will be again rise in temperature. The virus will be disseminated mainly in viscera, brain, and epithelial tract of urinary bladder, spleen, and kidney. Course may extend from 10-12 weeks. During this stage there will be haemorrhagic gastro enteritis, giant cell pneumonia, respiratory distress and discharges. Initially the discharges will be clear, but because of the involvement of lungs, later it will become mucopurulent. Vesicle/pustules formation can be noted in the internal aspect of thigh and in chest region. Later these vesicles/pustules will dry up and scab will form. This type of distemper eruptions are known as distemper exanthema. When nervous system is affected there will be encephalitis and convulsions can be seen. Restlessness, irritation and paralytic symptoms also can be seen. In little percentage of cases, animal will show movements like circling; jumping that gives the name St. Vituse’s dance. Later animal will show chorea (jerky movements of group of muscles) and permanent paralysis of limbs. A condition of old dog encephalitis with mental disorders, motor deterioration and death also described. Mortality may go up to 90-100% in case of nervous system involvement. In other cases there will be severe dehydration due to vomition and diarrhoea and subsequently death. In some cases, skin at foot pads and nose may become hard due to hyperkeratitis and the condition is termed as hard pad disease. Lesions: Severe haemorrhage on mucus membrane of digestive tract, intra nuclear and intra cytoplasmic inclusion bodies in lining cells of gall bladder, bile duct, alveolar lining and kidney. Diagnosis: Clinical symptoms, lab tests viz. FAT, SNT & ELISA. Intracytoplasmic inclusion bodies can be demonstrated in stained conjunctival smears. Animal inoculation studies can be done in dog or ferrets (using spleen of dead animals). DD from a. Rabies (IB seen in nervous tissue only, but in CD; IB seen in nervous tissue and CT) b. ICH – IN IB in hepatic cells. Treatment: Symptomatic. Fluid therapy, vitamin supplementation, Ointment for external lesion, non irritant food, anticonvulsants to reduce epileptic seizures and a course of antibiotic to tackle the secondary bacterial infection. Control: Vaccination. In very young pups we can give human measles vaccine which gives immunity for two months. Likewise, the pregnant female dogs also can be vaccinated with measles vaccine which can offer immunity to a maximum period of three months in pups. These pups should be vaccinated with CD vaccine later.
