Fruits, Vegetables, Worms and Fomites

A fomite is an inanimate object or substance that is capable of transmitting infectious organisms from one individual to another- objects like , books, money and medical equipment. From recent news reports we were made aware of the potential transport of Salmonella and other enteric pathogens via lettuce, tomatoes, and other vegetables. Even though these are living organisms we might be tempted logically to classify them as fomites.

Let me give you another scenario: I recall from one of my early medical schooldays of a lecturer commenting that several cases of syphilis were actually transmitted to human with apples and not through the more conventional routes. According to my recollections the vendor presumably a carrier of the disease had spit on his apples to shin them and make them more aesthetic for sale and that this resulted in 4 or his customers contacting this Treponema parasite!

Let us explore the apple scenario more deeply. I remember taking scrapings from the stem portion of apples- an area that is often poorly washed - suspending the contents in water, and then placing the material on microscopic slides and finally viewing the slide microscopically. It showed debris containing staminal hairs and other web-like structures which could serve as excellent fomites. However I was surprised to also observe in these slides small round worms wiggling in the microscopic field ! Yes they were alive and although not classified I tentatively assigned them to the genus Ascaris.

Now lets us suppose the apples had similar exposures as the vegetables in the earlier scene with the Salmonella and E. coli- In the case of "my apples " it is highly probable that a few pathogens (infectious organisms) could easily be left on their surface during the handling process for this debris and/or round worms to carry the infectious organisms to the people who eventually bought and ate the apples and these worms.

My question: Because my round worms were living they would belong in the same category as people with unclean hands or the surfaces of contaminated fruits and vegetables which are all parts of living animal and/or plant organisms. If we call the latter fomites then we should also place my apple scenario in this same category, i.e. they are they fomites ?

Let us look even further at another aspect of potential fomites- to my acknowledge an unexplored scenario- Suppose the round worms ingested these pathogens (infectious organisms) and then the public ate the apples together with those juicy round worms whose bellies were now full with those "contaminated " micro-organisms. And then suppose our digestive system freed these infectious bacteria and they (the bacteria) went on to produce diseases. Would the epidemiologists classify these infections as produced by fomites ? In my mind this hypothetical infectious process is no different from that of the public consuming tomatoes and/or lettuce which were washed with infected water or handled under unsanitary conditions by the farmers- Remember what is on the surface of organism as well as inside their bellies- is external to the organism. Therefore in my opinion all these scenarios are "fomites".

As a side line: We also know that the life cycle of many human protozoan diseases may have species lower in the animal kingdom as intermediate hosts for example: fish and tapeworms and Trichinella and swine for example . I urge the reader to review any text on parasitology 101 for more examples. So the obvious question related to such scenarios. .

"Could some human parasitic species with such life cycles of intermediate hosts and our rapid mode of transportation globally result in the transportion to our dinner tables from the tropics and elsewhere of foreign and exotic tropical infections ?

Seems to be that epidemiologists need to go back to their drawing books not only to review their definition of a fomite but how exotic infections can spread worldwide . This might even apply to AIDS and other current viral pandemics .