Rhinovirus: A genus of PICORNAVIRIDAE inhabiting primarily the respiratory tract of mammalian hosts. It includes over 100 human serotypes associated with the COMMON COLD.Common Cold: A catarrhal disorder of the upper respiratory tract, which may be viral or a mixed infection. It generally involves a runny nose, nasal congestion, and sneezing.Respiratory Tract Infections: Invasion of the host RESPIRATORY SYSTEM by microorganisms, usually leading to pathological processes or diseases.Picornaviridae: A family of small RNA viruses comprising some important pathogens of humans and animals. Transmission usually occurs mechanically. There are nine genera: APHTHOVIRUS; CARDIOVIRUS; ENTEROVIRUS; ERBOVIRUS; HEPATOVIRUS; KOBUVIRUS; PARECHOVIRUS; RHINOVIRUS; and TESCHOVIRUS.Isoxazoles: Azoles with an OXYGEN and a NITROGEN next to each other at the 1,2 positions, in contrast to OXAZOLES that have nitrogens at the 1,3 positions.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Enterovirus: A genus of the family PICORNAVIRIDAE whose members preferentially inhabit the intestinal tract of a variety of hosts. The genus contains many species. Newly described members of human enteroviruses are assigned continuous numbers with the species designated "human enterovirus".RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.Virus Diseases: A general term for diseases produced by viruses.Nasal Lavage Fluid: Fluid obtained by THERAPEUTIC IRRIGATION or washout of the nasal cavity and NASAL MUCOSA. The resulting fluid is used in cytologic and immunologic assays of the nasal mucosa such as with the NASAL PROVOCATION TEST in the diagnosis of nasal hypersensitivity.Poliovirus: A species of ENTEROVIRUS which is the causal agent of POLIOMYELITIS in humans. Three serotypes (strains) exist. Transmission is by the fecal-oral route, pharyngeal secretions, or mechanical vector (flies). Vaccines with both inactivated and live attenuated virus have proven effective in immunizing against the infection.Intercellular Adhesion Molecule-1: A cell-surface ligand involved in leukocyte adhesion and inflammation. Its production is induced by gamma-interferon and it is required for neutrophil migration into inflamed tissue.Receptors, Virus: Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.Cysteine Endopeptidases: ENDOPEPTIDASES which have a cysteine involved in the catalytic process. This group of enzymes is inactivated by CYSTEINE PROTEINASE INHIBITORS such as CYSTATINS and SULFHYDRYL REAGENTS.Antiviral Agents: Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.Viruses: Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells.Bronchi: The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.Nasopharynx: The top portion of the pharynx situated posterior to the nose and superior to the SOFT PALATE. The nasopharynx is the posterior extension of the nasal cavities and has a respiratory function.Viral Proteins: Proteins found in any species of virus.Echinacea: A genus of perennial herbs used topically and internally. It contains echinacoside, GLYCOSIDES; INULIN; isobutyl amides, resin, and SESQUITERPENES.Sneezing: The sudden, forceful, involuntary expulsion of air from the NOSE and MOUTH caused by irritation to the MUCOUS MEMBRANES of the upper RESPIRATORY TRACT.Capsid: The outer protein protective shell of a virus, which protects the viral nucleic acid.Nasal Mucosa: The mucous lining of the NASAL CAVITY, including lining of the nostril (vestibule) and the OLFACTORY MUCOSA. Nasal mucosa consists of ciliated cells, GOBLET CELLS, brush cells, small granule cells, basal cells (STEM CELLS) and glands containing both mucous and serous cells.Mengovirus: A strain of ENCEPHALOMYOCARDITIS VIRUS, a species of CARDIOVIRUS, isolated from rodents and lagomorphs and occasionally causing febrile illness in man.