Rabies is passed via saliva into a bite wound. The virus is injected into the muscle in a concentrated form, which is necessary for it to spread. It is also why infected people start to have an adverse reaction to water to avoid any dilution when the virus starts to spread (called shedding). It is generally understood that virus replication happens in the muscle cells and then moves into the fluid between each cell. The virus coats itself in a protein that passes nutrients and information. These cells then travel along the cell micro-tubular structure. The virus travels up the peripheral nervous system to the central nervous system, although this process is not completely understood. The virus then travels up the nervous system to the hippocampal area in the brain. This impacts the cranial nerves and the infection of the salivary gland epithelial cells enabling the infected dog to spread the disease via saliva. An infected person begins to experience difficulty with swallowing and choking, causing anxiety when they want to swallow.