number of immune cells that recognize the virus, allowing the virus to evade detection and elimination. The virus has many other evasion strategies against the host's immune system contributing to the virus being able to maintain lifelong infection in the animal. After primary infection of BoHV-1, the latent infection is quite often found in the trigeminal ganglion of the cow, although on occasion infection can enter the central nervous system. These latent infections can possibly reactivate, with or without clinical symptoms, under conditions of stress or by experimental methods. Infected animals will be continuous shedders throughout their lifetime when the virus reactivates; therefore, successfully propagating the disease. The virus sheds in such high titers that it will spread rapidly throughout a herd. Even though cattle might not be showing clinical signs they can still spread the disease. Aside from cattle, studies experimentally infecting animals have shown that goats and buffalo can act as reservoirs for BoHV-1, as well as red deer, sheep, swine, and reindeer. Shedding begins from the nasal mucosa as soon as infection occurs, and the virus has replicated in the upper respiratory tract. During replication in the respiratory tract cells of the epithelial will undergo apoptosis. The necrosis in the epithelial will result in an entry site for secondary infections that may result in shipping fever. Clinical signs Infectious bovine rhinotracheitis The respiratory disease caused by BoHV-1 is commonly known as infectious bovine rhinotracheitis. This disease affects the upper respiratory tract as well as the reproductive tract of cattle, and is commonly found in feedlots across North America. Clinical symptoms include fever, serous to mucopurulent nasal discharge, coughing, sneezing, difficulty breathing, conjunctivitis and loss of appetite. Ulcers commonly occur in the mouth and nose. Mortality may reach 10 percent. IBR can also cause abortion. This generally occurs in mid-gestation when a susceptible cow is infected with BoHV-1. A viraemia occurs and subsequently the virus crossed the placenta and causes organ necrosis in the fetus. BoHV-1 also causes a generalized disease in newborn calves, characterized by enteritis and death. Infectious pustular vulvovaginitis and infectious balanoposthitis The genital disease causes infectious pustular vulvovaginitis in cows and infectious balanoposthitis in bulls. Symptoms include fever, depression, loss of appetite, painful urination, a swollen vulva with pustules, ulcers, vesicles and erosions in cows, and pain on sexual contact in bulls. In both cases lesions usually resolve within two weeks. Diagnosis Clinical signs