Question

Which chemical agent is effective against enveloped viruses, such as influenza and herpes viruses?

• A. Ethylene oxide
• B. Benzalkonium chloride
• C. Chlorine dioxide
• D. Quaternary ammonium compounds

Hint:

• Enveloped viruses have a lipid envelope that is vulnerable to disruption.
• Detergents, such as Quaternary Ammonium Compounds (Quats), are effective because they disrupt these lipid structures.
• Alcohols (e.g., ethanol, isopropanol) are also highly effective against enveloped viruses by denaturing proteins and dissolving lipids.
• Enveloped viruses are generally easier to inactivate with disinfectants than non-enveloped viruses.

Answer 1

The Correct Option is D

Enveloped viruses possess an outer lipid membrane (envelope) derived from the host cell membrane, which surrounds their protein capsid and nucleic acid. This lipid envelope makes them generally more susceptible to certain chemical agents compared to non-enveloped (naked) viruses. Agents that can disrupt lipids are often effective.

• Quaternary Ammonium Compounds (Quats): These are cationic detergents (e.g., benzalkonium chloride, cetylpyridinium chloride). They act by disrupting cell membranes and viral envelopes due to their surfactant properties. They are widely used as disinfectants and are effective against many bacteria, fungi, and enveloped viruses.
• Benzalkonium chloride (option b) is an example of a quaternary ammonium compound. So, if benzalkonium chloride is effective, then the broader class "Quaternary ammonium compounds" (option d) is also correct and perhaps more encompassing if other Quats are also effective. In MCQ, if a specific example and its class are both correct options, the context or common phrasing in the field might lean towards one. Here, "Quaternary ammonium compounds" is a well-recognized group effective against enveloped viruses.
• Ethylene oxide (option a) is a sterilizing gas effective against all microorganisms, including viruses and spores, but it's used for heat-sensitive materials under controlled conditions, not typically as a general surface disinfectant for viruses like influenza.
• Chlorine dioxide (option c) is a strong oxidizing agent and a broad-spectrum disinfectant/sterilant, effective against bacteria, viruses (both enveloped and non-enveloped), fungi, and spores. It is effective, but Quats are specifically known for their action on lipid envelopes.

Considering the options, Quaternary ammonium compounds (d) are a well-established group of disinfectants effective against enveloped viruses by targeting their lipid envelope. Benzalkonium chloride (b) falls under this category. Given that (d) is a broader class that includes (b) and other similar effective agents, and is a standard answer for agents targeting lipid envelopes, it's often preferred if the question is about a general class of agents. Influenza and herpes viruses are both enveloped viruses. \[ \boxed{\text{Quaternary ammonium compounds}} \]