Necrotic rhinitis follows injury to the oral or nasal mucosa and is often accompanied by infection with Fusobacterium necrophorum. Signs include facial swelling, sneezing, nasal discharge, loss of appetite, and emaciation. Diagnosis is based on signs and bacterial culture. Prevention is based on avoiding injuries to the mouth. Because teeth clipping is no longer widely practiced, this disorder is greatly reduced in significance.
Necrotic rhinitis is an uncommon, sporadic disease of young pigs characterized by suppuration and necrosis of the snout, arising from wounds of the oral or nasal mucosa. Confusion exists in the literature because of the use of the misnomer “bullnose” to also describe atrophic rhinitis.
Etiology of Necrotic Rhinitis in Pigs
Fusobacterium necrophorum is commonly isolated from the lesion and undoubtedly contributes to necrotic rhinitis, but other types of organisms are frequently present. They gain entry through damage to the roof of the mouth, often as a result of clipping the needle teeth too short or using blunt clippers.
Clinical Findings and Lesions of Necrotic Rhinitis in Pigs
Signs of necrotic rhinitis include:
swelling and deformity of the face
occasionally hemorrhage
snuffling
sneezing
foul-smelling nasal discharge
sometimes involvement of the eyes with lacrimation and purulent discharge
loss of appetite
emaciation
Generally, only one or two pigs in a herd are affected.
The facial swelling usually is hard, but incision reveals a mass of pinkish gray, foul-smelling necrotic tissue, or greenish gray tissue debris, depending on the age of the lesion. The nasal and facial bones become involved, and facial deformity may be marked.
Diagnosis of Necrotic Rhinitis in Pigs
Clinical signs and culture of F necrophorum from affected pigs
Necrotic rhinitis is readily differentiated from atrophic rhinitis by the bulging type of facial distortion seen in the former. The character of the exudate and its location within the tissue of the snout or face are also distinctive of necrotic rhinitis.
Prevention and Treatment of Necrotic Rhinitis in Pigs
Avoidance of mouth and snout injuries and improved sanitation help prevent necrotic rhinitis
Because teeth clipping is no longer routinely practiced, necrotic rhinitis has reduced in significance. Prevention is directed toward avoiding injuries to the mouth and snout, improving pig processing techniques, and improving sanitation. When the disease occurs repeatedly, needle teeth should be clipped carefully.
If necrotic rhinitis is advanced, treatment may not be advisable. Early surgical intervention and packing the cavity with sulfonamide or tincture of iodine may be useful. In young pigs, sulfamethazine can be given at 250 mg/kg per day in drinking water on the first day and 125 mg/kg per day on subsequent days, but not to exceed a total of 5 consecutive days.
Key Points on Necrotic Rhinitis in Pigs
Necrotic rhinitis is a rare condition.
Avoidance of teeth clipping effectively eliminates necrotic rhinitis.
