naked virus, nonenveloped virus a virus lacking an outer lipoprotein bilayer. neurotropic virus one that has a predilection for and causes infection in nervous tissues, e.g., the rabies virus. Norwalk virus a calicivirus that is a common agent of epidemics of acute gastroenteritis. oncogenic viruses an epidemiologic class of viruses that are acquired by close contact or injection and cause usually persistent infection; they may induce cell transformation and malignancy.
Define stumbling block: an obstacle to progress; an impediment to belief or understanding : perplexity â stumbling block in a sentence an obstacle to progress; an impediment to belief or understanding : perplexityâ¦
Heart block is a type of arrhythmia (ah-RITH-me-ah). An arrhythmia is any problem with the rate or rhythm of the heartbeat. Some people are born with heart block, while others develop it during their lifetimes. If you're born with the condition, it's called congenital (kon-JEN-ih-tal) heart block.