Seoul virus is a type of hantavirus (family: Bunyaviridae ) that is transmitted from rats to humans after exposure to aerosolized urine, droppings, or saliva of infected rodents, or after exposure to dust from their nests or bedding. Transmission may also occur from rat bites or when contaminated materials are directly introduced into broken skin or onto mucous membranes. For Seoul virus, the natural host is the black rat (Rattus rattus) and the Norway rat (Rattus norvegicus). This virus has been found in both pet rats and wild rat populations around the world. The diagnosis of Seoul virus is mainly based on detection of viral RNA by PCR method.