Question: How many viruses are recognized as the type of virus that poliovirus is? Passage 1:Poliovirus is an enterovirus. Infection occurs via the fecal–oral route, meaning that one ingests the virus and viral replication occurs in the alimentary tract. Virus is shed in the feces of infected individuals. In 95% of cases only a primary, transient presence of viremia (virus in the bloodstream) occurs, and the poliovirus infection is asymptomatic. In about 5% of cases, the virus spreads and replicates in other sites such as brown fat, reticuloendothelial tissue, and muscle. The sustained viral replication causes secondary viremia and leads to the development of minor symptoms such as fever, headache, and sore throat. Paralytic poliomyelitis occurs in less than 1% of poliovirus infections. Paralytic disease occurs when the virus enters the central nervous system (CNS) and replicates in motor neurons within the spinal cord, brain stem, or motor cortex, resulting in the selective destruction of motor neurons leading to temporary or permanent paralysis. In rare cases, paralytic poliomyelitis leads to respiratory arrest and death. In cases of paralytic disease, muscle pain and spasms are frequently observed prior to onset of weakness and paralysis. Paralysis typically persists from days to weeks prior to recovery.
 Passage 2:Archaeological findings in the area date back to the Neolithic era, especially the stilt houses of the Mondsee group culture, who settled the region from about 3800 BC onwards. The Germanic name hall of several settlements refers to the region's numerous salt mines, which had been in use at least since the days of the Celtic Hallstatt culture, centered at the mining town of Hallstatt. These operations were continued by the Romans, after the area had been incorporated into the Noricum province in 15 BC. A Roman settlement and salt evaporation pond at Hallstatt is documented about 100, affected by several Germanic invasions after the Marcomannic Wars, until the province was finally evacuated at the behest of the Italian king Odoacer in 488.
 Passage 3:With the ascendance of Simeon I to the throne in 893, the long-lasting peace with the Byzantine Empire established by his father was about to end. A conflict arose when Byzantine Emperor Leo VI the Wise, acting under pressure from his wife Zoe Zaoutzaina and her father, Stylianos Zaoutzes, moved the marketplace for Bulgarian goods from Constantinople to Thessaloniki, where Bulgarian merchants were heavily taxed. Forced to take action, in the autumn of 894 Simeon invaded the Byzantine Empire from the north, meeting little opposition due to the concentration of most Byzantine forces in eastern Anatolia to counter Arab invasions. Informed of the Bulgarian offensive, the surprised Leo sent an army consisting of guardsmen and other military units from the capital to halt Simeon, but his troops were routed somewhere in the theme of Macedonia.The Magyars managed to defeat Simeon's army twice, but in 896 they were routed in the Battle of Southern Buh. The war ended in 896 with a great Bulgarian victory near Bulgarophygon in Eastern Thrace. The market was returned to Constantinople, and the Byzantine Emperor had to pay annual tribute to Bulgaria. More importantly, with help from the Pechenegs Simeon successfully fended off a Magyar invasion, which was coordinated with the Byzantines.

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