How does Nipah affect the body?
A person can contract the Nipah virus either by coming into contact with contaminated bat saliva or excreta on fruit or trees or by handling other animal hosts like infected pigs. A person can also get Nipah from another infected person. The virus has an incubation period of between five and 14 days after which the person starts to exhibit symptoms of infection.
The virus first attacks the respiratory system. A study by infectious disease researchers in the United States published in the journal PLOS in 2016 described experiments with hamsters in which they found that Nipah virus on to the lining of the nasal cavity, respiratory tracts and the lungs and starts replicating, sometimes as early as eight hours after infection. In the first 48 hours, the virus is able penetrate into underlying tissue and get in to blood vessels that can carry the virus through the body. Similarly in the virus replicates in the nasal cavity, which is possibly the first step towards the virus infiltrating the nervous system, using the olfactory nerve to access the brain and spinal cord.
Other research suggests that the Nipah virus is able to increase the permeability of the blood brain barrier, which is a semipermeable membrane separating the blood from the cerebrospinal fluid. The virus does this by disrupting certain tight junction complexes in this membrane. Still more studies suggest that the Nipah virus, like Ebola, is able to disrupt the immune system by co-opting the function of some of its components to enhance its own replication.
A person infected with Nipah will initially experience flu-like symptoms, with fever, headache, sore throat and muscle pain. Once the virus takes over a person’s vascular and neurological systems, he may experience drowsiness, disorientation, signs of brainstem dysfunction, convulsions, or go into a coma. Some patients may not may not develop neurological signs but have pneumonia or acute respiratory distress syndrome. Severely ill patients may also have septicemia, bleeding from the gastrointestinal tract and renal impairment. Patients who survive Nipah virus encephalitis may have mild to severe residual neurological deficits. The disease has a high fatality rate, with major reported outbreaks claiming the lives of half of those infected.