Three serotypes of poliovirus have been identified – wild poliovirus type 1 (WPV1), type 2 (WPV2), and type 3 (WPV3) – each with a slightly different capsid protein. All three are extremely virulent and produce the same disease symptoms. PV1 is the most commonly encountered form, and the one most closely associated with paralysis. WPV2 was certified as eradicated in 2015 and WPV3 certified as eradicated in 2019.Individuals who are exposed to the virus, either through infection or by immunization via polio vaccine, develop immunity. In immune individuals, IgA antibodies against poliovirus are present in the tonsils and gastrointestinal tract and able to block virus replication; IgG and IgM antibodies against PV can prevent the spread of the virus to motor neurons of the central nervous system. Infection or vaccination with one serotype of poliovirus does not provide immunity against the other serotypes, and full immunity requires exposure to each serotype.A rare condition with a similar presentation, nonpoliovirus poliomyelitis, may result from infections with enteroviruses other than poliovirus.The oral polio vaccine contains weakened viruses that can replicate. On rare occasions, these may be transmitted from the vaccinated person to other people, who may display symptoms of polio. In communities with good vaccine coverage transmission is limited, and the virus dies out. In communities with low vaccine coverage, this weakened virus may continue to circulate. Polio arising from this cause is referred to as circulating vaccine-derived polio (cVDPV) in order to distinguish it from the natural or "wild" poliovirus (WPV).
Ectopic beats are a type of cardiac arrhythmias, which is a variety of cardiac abnormalities relating to rate or rhythm of the cardiac cycle.Ectopic beats may become more frequent during anxiety, panic attack, and the fight-or-flight response due to the increase in sympathetic nervous activity or due to parasympathetic failure, stimulating either more frequent or more vigorous contractions and increasing stroke volume. The consumption of nicotine, alcohol, epinephrine and caffeine may also increase the incidence of ectopic beats, due to their influence on the action of cardiomyocytes. See also
Heart arrhythmia § Origin of impulse
Ectopia (disambiguation)
Junctional escape beat
Palpitation
Premature junctional contraction
Ventricular escape beat

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