Phocine Distemper Viruses (PDVs) are a group of closely related viruses that belong to the genus Morbillivirus, which primarily infects marine mammals, particularly seals. These viruses are responsible for causing phocine distemper, a highly contagious and often fatal disease that affects various species of seals, especially harbor seals (Phoca vitulina).
PDVs are enveloped, single-stranded RNA viruses that possess a characteristic helical nucleocapsid. They have a diameter of around 200-300 nm and are classified under the family Paramyxoviridae. PDVs are closely related to other Morbilliviruses that affect terrestrial mammals, such as dogs, humans, and cattle.
Infection with PDVs can lead to severe clinical symptoms, including fever, respiratory distress, conjunctivitis, and neurological disorders. Seals affected by phocine distemper often exhibit lethargy, loss of appetite, and skin lesions. The disease can spread quickly within seal populations, resulting in significant mortality rates, particularly in younger seals.
Transmission of PDVs typically occurs through direct contact between infected and susceptible seals or through exposure to contaminated body fluids, such as respiratory secretions or feces. However, indirect transmission via environmental contamination can also play a role in spreading the disease.
Efforts to control PDV outbreaks in seals include monitoring and surveillance programs, as well as quarantine measures to prevent the spread of the virus. Vaccination has shown some success in reducing the impact of phocine distemper, but controlling the virus in the wild remains challenging due to the difficulty in reaching and immunizing large seal populations.
