By Frank Hubbell, DO

Illustrations By T.B.R. Walsh


What do cashews, mangos, and pistachios have in common with poison ivy? As unbelievable as it seems, they share one very unpleasant secret: urushiol.

Most everyone loves cashew nuts, considering them a  tasty treat.  Recently we were in Costa Rica, and as we were heading for a National Park, the driver of our tour bus stopped by the side of the road to pick a funny-looking, pear-shaped, bright red fruit from a tree. After he gave the fruit to us to exam, he explained that it was a cashew apple and attached to the bottom of it was a single cashew nut, referred to as drupe. He then related that the cashew was a member of the poison ivy family and was, which quite toxic.

What’s up with that?

As it turns out cashews, mangos, pistachios, ginko bilboa, poison ivy, poison oak, and poison sumac all belong to the same plant family Anacardiaceae.  What these plants all have in common is that they contain the toxin urushiol. 

Urushiol is an oily organic allergen that is well known for causing the classic red, itchy poison ivy rash.

Urushiol Facts: This is one amazing toxin!

– Only 1 nanogram (one billionth of a gram) of the urushiol will cause the rash.

– An average of 100 nanograms of the urushiol will cause a rash in 90% of people.

– ¼ ounce of urushiol is all that is needed to cause a rash on every person on earth.

– The amount of urushiol that would fit on the head of a pin will cause a rash on 500 people.

– Urushiol will remain active for 1 – 5 years on surfaces, in clothing, and on plants that have died. This explains why people can get poison ivy rashes in the middle of the winter when the plants are dormant or gone.

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Roundworms – Hookworms

March/April 2012 ISSN-1059-6518 Volume 25 Number 2



 BY Frank Hubbell, DO

In the previous several issues of the WMNL, we discussed the Phylum of parasitic tapeworms Cestoda. Over the next several issues of the WMNL, we will explore the group of parasitic roundworms – the Nematodes.


Nematodes are considered to the most diverse orders of animals on earth. Estimated that there are over 1,000,000 species of nematodes, 28,000 species have been described.

16,000 of these species are parasitic, of which approximately a dozen parasitize humans.

It has often been noted, that every living thing on earth, whether plant or animal, harbors so many harmless nematodes in their “body” structures, that if all of their body tissues were to disappear, the nematodes left behind would still define their shape and cast a recognizable shadow.

One of the distinctive characteristics of Nematodes, roundworms, is that they have a tubular digestive system with an opening at both ends.


Parasitic Nematodes:


Necator americanis / Ancylostoma duodenale – hookworm

Ancylostoma braziliense – cutaneous larva migrans

Strongyloides stercoralis – threadworm

Ascariasis lumbricoides  – giant roundworm

Dracunculus medinensis – guinea worm

Enterobius vermicularis – pinworm, threadworm, seatworm

Wucheria bancrofti, Brugia malayi, Brugia timori – lymphatic filariasis (elephantiasis)

Onchocerca volvulus – river blindness

Trichuris trichiura – whipworm

Trichinella spiralis – trichinosis

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Plants that Bite and Sting

It is estimated that there are around 375,000 species of plants on our planet, of which 297,366 have been identified and named. There are about 260,000 flowering plants, (they have flowers and reproduce by pollination and seeds), and 15,000 bryophytes (they reproduce by spore production – liverworts, hornworts, and mosses).

Without plants life as we know it would not exist. This is because, through the process of photosynthesis, plants have the remarkable ability to combine carbon dioxide (CO2) and water (H2O), using photons of energy from the sun, to form glucose. Glucose is how plants store energy. Animals consume the plants, extract and digest the stored sugars, carbohydrates, and starches, and use the stored energy to survive. These simple sugars, glucose and fructose, are the fuel that the engine of life utilizes to sustain and maintain itself.


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November/December 2010  ISSN-1059-6518  Volume 23 Number 6

By Frank Hubbell, DO

Illustrations by T.B.R. Walsh


For the past 5 issues of the WMNL, we have discussed human ectoparasites. In this issue we will complete the topic with a discussion about bedbugs.

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