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¦
1 Block (rural Australia), a small agricultural landholding. 2  Block (district subdivision), administrative region in some South Asian countries. 3  City block, the smallest area that is surrounded by streets.  License block, a geographically defined area for the purpose of the extraction of natural resources.