contagious and infectious

質問

What is the difference between "contagious" and "infectious"?

They both seem to have the meaning of propagating diseases.

Does either of them have the meaning of "direct (by physically contacting)" propagation and the other is aerial propagation?

回答No.3

Him-hymn · ベストアンサー

The word "contagious" has a meaning of contact in it as it originally came from a Latin word "contagious." It means, according to ODE, to spread from one person or organism to another by direct or indirect contact. (Note the final word "contact.")

The word "infectious," on the other hand, means to liable to be transmitted to people, organisms, etc. through the environment, or likely to spread or influence others in a rapid manner.

According to ODE, there is little or no difference in meaning of the two words, but there is a difference in emphasis or focus between the two words. Contagious tends to be focused on the person or animal affected by the disease while infectious emphasizes the agent or organism which carries the disease. There are, for example, plenty of examples in the Oxford English Corpus of infectious agent but none of contagious agent.

As for the second question, I've found the following sentence in an Oxford dictionary.

Spread by virus-infected droplets that are coughed or sneezed into the air, the flue is contagious. In this contact, both words are used in the aerial propagation and I assume there is no such distinction in meaning as one is direct and the other is aerial.

お礼

Thank you very much for the details.

It is interesting to consider the origin of the word (from a Latin).

Also, the difference in the emphasis is interesting to know.

回答No.2

miknnik

**Does either of them have the meaning of "direct (by physically contacting)" propagation and the other is aerial propagation?

The short answer is 'no.'

Having said that, 'contagious' and 'infectious' are not exactly the same though they are often used interchangeably.

The word, infectious, of course derives from 'infection.' As you may know, bacteria and viruses cause infections; however, not all infections are contagious, e.g., UTI (urinary tract infection). When you say 'infectious disease,' it just means that the ailment is caused by either bacteria or a virus. If a certain infection can spread from one person to another (there are several ways to transmit the germs such as fecal-oral transmission, airborne, droplet, direct physical contact, etc.), it is contagious. Many infections are contagious like influenza, norovirus infection, mononucleosis for instance.

For your information, only bacterial infections can be treated with antibiotics. There are no medications to treat viral infections (except, as far as I know, Tamiflu for the flu, but it may have serious side effects). While one may have to suffer for seven to ten days depending on what they got in their system, doctors often assure them a viral infection is not fatal so long as they keep themselves hydrated and well rested.

お礼

Thank you very much for the detailed information.

I could study a lot.

回答No.1

marbleshit

Yes, it does. "Contagious" means propagation by directly touched while "infectious" is rather easily diffused or spread including aerial propagation.

お礼

Thank you very much for your reply.