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¦
a hollow masonry building unit of cement, terra cotta, etc.: a wall made of concrete blocks. one of a set of cube-shaped pieces of wood, plastic, or the like, used as a child's toy in building. a mold or piece on which something is shaped or kept in shape: a hat block.