What’s Lurking Under Your Fingernails?
In the spring of 1997, I spent a wonderful day with Dr Omar Amin in Phoenix, Arizona. Dr Amin is one of the respected and sought-after parasitologists in the world and runs the Parasitology Center Inc in Scottsdale, Arizona.
He offered me a copy of his paper ‘Understanding Parasites’ in which there was a sentence that has always stuck inside my mind: “A recent inspection of an expensive restaurant in Los Angeles showed that 100% of all employees (not just servers) had fecal matter under their nails”.
Fecal matter and disease (particularly parasites) generally go together. With our cities offering cuisine from increasingly exotic parts of the world, this carries a higher incidence of parasite-borne diseases, especially if these regional foods are undercooked or even raw: Dutch herring, steak tartar, ceviche, sashimi, sushi for example. Tapeworm is high on the list of ‘residents’ during these foods as is the Anisakid Worm.
A food-handler with poor personal hygiene will more than likely increase the exposure and risk of pathogenic organisms spreading. Years ago kitchen staff wore gloves and hairnets when handling food. They don’t seem to do this anymore although regular hand-washing habits might be mandatory nowadays.
University of Gondar, Ethiopia
In 2003, 127 food-handlers doing work in the cafeterias of the University of Gondar and the Teachers Training College there were fingernail-tested. These cafÃ©’s were selected because the mass-provision of foods is a likely source of transmitting infections. Fingernail contents of both the hands and stool specimens were collected from all 127 food-handlers. In addition to fecal matter under the fingernails, these was found:
– Coagulase-negative staphylococci (41. 7%) by Staphylococcus aureus (16. 5%), Klebisella species (5. 5%), Escherichia coli (3. 1%), Serratia species (1. 58%), Citrobacter species (0. 8%), and Enterobacter species (0. 8%).
– Shigella species were isolated from stool samples of four food-handlers (3. 1%). None of the food-handlers was positive for Salmonella species and Shigella species in respect of their fingernail contents.
Thankfully no intestinal parasites were detected from fingernail contents, but intestinal parasites were detected within their stools:
– Ascaris lumbricoides (18. 11%), Strongyloides stercoralis (5. 5%) Entamoeba histolytica/dispar (1. 6%), Trichuris trichiura (1. 6%), hookworm species (0. 8%), Gardia lamblia (0. 8%), and Schistosoma mansoni (0. 8%); 1 . 6% of the study subjects were positive for each of the. lumbricoides, T. trichiura, hookworm, and Giardia lamblia.
It’s clear using this and many other studies that food-handlers really are a potential source of infections. It’s not just food handlers though. To provide you with an idea of where and how contamination occurs, here are a couple of lists.
The 10 ‘dirtiest’ jobs:
1. Teacher/day-care worker
2. Cashier (bank, post office, supermarket, fast foods etc)
4. Animal control officer
5. Janitor, plumber
6. Computer repair (using dirty keyboard/mouse)
7. Doctor or nurse
8. Laboratory scientist
9. Rubbish collector
10. Meat packer
Here are some of the dirtiest places you’ll touch in your day:
1. Supermarket trolley handle
2. Office keyboard (not yours) and mouse
3. The button on a public or office drinking fountain
4. Door handles – toilet, refrigerator and microwave at office and home
5. Vending machine buttons
6. The kitchen sink inside your home
7. Your toothbrush, if left near to a flushed toilet (always close the toilet lid! ) as well as the toothbrush holder
8. TV remote control (hotels and home)
9. Anywhere around household pets (including sandboxes)
10. Escalator handrails
11. The buttons on ATM’s, lifts, video game controllers
12. Petrol pumps
13. Car steering wheels, especially with multiple drivers
Next time you go out for a glass or two, think before you dip your fingers into the bowl of peanuts on the bar. Alongside the nuts will be waste materials and urine residue. Then obviously there’s that lemon wedge inside your drink:
“I worked in restaurants for years and here is what I saw. The lemons and limes were delivered and put into the walk-in cooler. When the bartender needs a hand full of them he would go grab them by putting them in his apron. He would then slice them up on a cutting board and put them into cups and place them on the bar. Customer # 1 orders a beer and pays for the beer. The bartender stuffs the cash into the register. Customer # 2 orders a vodka and soda with a lemon. Bartender reaches into the ice bin and fills the cup, grabs a lemon and squeezes the lemon into the drink. At no time does any water touch the fruit or his hands and this goes on all day. Money, ice and fruit. Oh, and the occasional trip to the john.”
Men generally have more germs under their fingernails than women but there are more germs found under artificial nails than under real ones.
There is of course hope…
Viruses and bacteria invariably is an integral part of our lives. There are billions of them in and around us. A powerful, healthy immune system will generally care for most of the daily threats we grab from that dirty supermarket trolley or domestic pet but being conscious about this is also valuable.
Some Nail Facts:
â? onychopathy will be the study of fingernails and toenails.
â? Fingernails are essentially dead cells that are made of a protein called keratin – the same stuff as our hair. We’d go along fine without them but they’re great at help us do fiddly things like gripping things better, text messaging and scratching ourselves. They also absorb some of the stress the tip of the finger bones would otherwise have to bear.
â? Fingernails grow quicker when you’re young, faster on your more active hand and much more in summer than winter. They also grow faster on women that are pregnant.
â? Dry nails? Just drink significantly more water.
On a final health note…
Try not to drink straight from aluminium cans. If you buy canned drinks and bring them home, wash the tops as they may carried a virus called Leptospirosis.
There’s much scaremongering on the internet about people dying from drinking out of unwashed cans. I’m not sure about the accuracy of the but if there’s any truth here, it would be because the victim had this kind of depleted immune system, offering little if any resistance from the invading bacteria.
Tests have demostrated that some aluminium cans carry dried rat urine containing Leptospira i. Cans are usually stored in rat-infested warehouses and delivered direct to retail stores without cleaning! Just therefore you know.
Let’s keep the exposure to at least.