Kennel cough is infectious bronchitis in canines worldwide characterized by harsh and hacking cough (McCandlish et al., 1978). The disease appears to be multifactorial and a number of viral and bacterial pathogens have been reported as potential aetiological agents, including Canine Parainfluenza virus, Canine Adenovirus, Herpesvirus, Reovirus and Bordetella bronchiseptica, Mycoplasmas etc (Veland, 1989). Reports of kennel cough in outbreak form are meagre in Indian scientific literature. Present report describes kennel cough in dogs in an outbreak form and its therapeutic management.
Materials and Methods
Ten Labrador dogs aged 4-9 months weighing 12-19 kg were presented with history of dry cough followed by retching and gagging, respiratory distress for last 4-5 days. The animals were alert and active with normal feed and water intake. Dogs were properly dewormed and vaccinated with six in one and anti rabies vaccines and they were living together in the same kennel. Complete clinical examination was performed as per standard procedures. Blood samples were collected and sent to diagnostic laboratory for haematology, biochemistry and haemoprotozoan examination. Lateral and ventro-dorsal radiographic views of chest were performed. Dogs were treated with Cefpodoxime @10mg/kg b.wt. o.d orally (Cefpet (a)), Meloxicam @ 0.2mg/kg b. wt. orally bid (Melonex (a)) and antitussiveantihistaminic (Chericof (b)) @ 1 tsf orally bid. Initially the treatment was continued for 7 days and after 7 days, based on response to treatment, Meloxicam therapy was withdrawn and antibiotic and anti-tussive continued for next one week.
Results and Discussion
Kennel cough is a multifactorial disease usually caused by bacteria, virus, mycoplasma and characterized by harsh dry hacking cough. Initially two animals were affected with the disease and over a period of one week it spread to other mates of kennel. Typical clinical signs were dry hacking cough followed by retching, gagging. Clinical examination of dogs revealed normal to slightly elevated body temperature (102[degrees]F to 103.6[degrees]F), tachypnea (52-64/minute), normal heart rate (80-94/minute) and normal mucus membrane. Palpation of trachea induced coughing. Auscultation of chest revealed harsh bronchial lung sounds. Haematological findings were Haemoglobin-11.79 [+ or -] 0.392 g/dl (9.2-12.5g/dl), Packed cell volume-31 [+ or -] 0.898% (24.7-34%), Total erythrocyte count-5.753 [+ or -] 0.176 x [10.sup.6]/L (4.35-6.4 x [10.sup.6] /L), Total leucocyte count - 24756 [+ or -] 4884.62/[micro]1 (11070-60150/[micro]l), neutrophils 20204.7 [+ or -] 4339.87/[micro]jl (7749-50526/[micro]1), lymphocytes-4139.8 [+ or -] 705.69/|jl (1765-9624/[micro]1). Eosinophilia was observed in two animals only. Serum biochemistry revealed normal alanine aminotransaminase (ALT)-32.5 [+ or -] 4.92U/L (20-44U/L), bilirubin-0.725 [+ or -] 0.21U/L (0.2-1.2mg/dl), blood urea nitrogen (BUN)-13.5 [+ or -] 2.53mg/dl (7-18mg/ dl) and creatinine-0.475 [+ or -] 0.075mg/dl (0.3-0.6mg/ dl) and high alkaline phosphatise (AKP)202.5 [+ or -] 41.1 U/L (131-321U/L). Radiographic findings were moderate to severe mixed pattern (bronchial and interstitial) in cranial and caudal lung lobes. However, the isolation of causative agent was not carried out in these animals but based on presence of typical clinical signs in all dogs, pattern of spread of disease in kennel and similar radiographic and haemato-biochemical findings, the dogs were diagnosed to be suffering from kennel cough (Kahn et al., 2005).
Dogs catch kennel cough when they inhale bacteria or virus particles into their respiratory tract. This tract is normally protected by mucociliary defence mechanism that traps infectious particles. Infectious organisms weaken this protection and cause kennel cough infection. Invading microorganisms cause primary bronchitis which spread to involve surrounding pulmonary parenchyma causing coughing, respiratory distress and harsh lung sounds. Cough occurs due to stimulation of receptors in throat and respiratory passage. Marked leucocytosis with neutrophilia, might be due to secondary bacterial complication. Usually several gram negative organisms may cause secondary infection after injury to respiratory tract by primary pathogen (Kahn et al., 2005).
Treatment of animals with antibiotic, anti-inflammatory and anti-tussive lead to marked clinical recovery after 7 days of treatment. Frequency and intensity of coughing and respiratory distress also reduced. Total leukocyte count was reduced towards normal. Treatment of animals with antibiotics and anti-tussive continued for next 7 days. After 14 days of treatment, all the animals recovered completely with no coughing, normal respiratory movements and normal lung sounds on auscultation. Though uncomplicated kennel cough is a self limiting disease but in these dogs, treatment was undertaken to control the secondary bacterial infection. Cefpodoxime, a third generation semisynthetic cephalosporin exhibits activity against several gram positive as well as gram negative microorganisms and is stable in beta lactamase environment (Riviere and Papich, 2009). Antitussive and anti-histaminics were used to suppress cough reflex due to irritation of airways by inflammatory mediators, histamine and inflammatory exudates. Dextromethorphan is an antitussive drug which exerts its action in central nervous system to elevate the threshold of coughing. Anti-histaminic provide symptomatic relief in cough because of their sedative and anticholinergic action (Riviere and Papich, 2009).
An outbreak of kennel cough was diagnosed in dogs on basis of history of spread, clinical, hematobiochemical and radiographic findings. Treatment of animals with antibiotics, antitussive, antihistaminics lead to complete clinical recovery within two weeks of treatment.
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McCandlish, I.A., Thompson, H., Cornwell, H.J. and Wright, N.G. (1978). A study of dogs with kennel cough. Vet. Record 102: 293-301.
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Veland, K. (1989). Outbreak of kennel cough in Norvey. Vet. Rec. 124:642.
N. Chand , S.K. Uppal, P.S. Dhaliwal and S. Turkar
Department of Veterinary Medicine
College of Veterinary Science
Guru Angad Dev Veterinary and Animal Sciences University (GADVASU)
(1.) ICAR-Central Institute for Research on Cattle, Meerut Cantt and Corresponding author.
(a)--Brand of Intas Animal Health, Ahmedabad
(b)--Brand of Ranbaxy Ltd., Delhi