Animal-related Infection


Helminths

From the CDC web site:

"Helminths are large, multicellular organisms that are generally visible to the naked eye in their adult stages. Like protozoa, helminths can be either free-living or parasitic in nature. In their adult form, helminths cannot multiply in humans. There are three main groups of helminths (derived from the Greek word for worms) that are human parasites:

These organisms have fairly complex anatomy and they tend to have complex reproductive cycles as well. Note, however, that in order for humans to become infected with the fish tapeworm, the feces of infected human needs to find its way into water, and humans have to eat raw fish from contaminated waters.

Examples of Flatworm Anatomy and Life Cycle

FlatwormAnatome.jpg

Liver fluke anatomy (a flatworm)

 

FishTapeWorm_life-cycle.png

Life Cycle of the Fish Tapeworm

Schistosome Life Cycle2.png

Schistosome Life Cycle.png

 

The next table (below) illustrates the anatomy and life cycle of a hookworm, a roundworm.

Hookworm (a round worm) Anatomy and Life Cycle

hookworm_anatomy.jpg

Adult Male (left) and Female (right) Hookworms

Hookworm_LifeCycle.gif

Guinea worm.jpg

Guinea worm

See life cycle to the right.

Dracunculiasis_LifeCycle.gif

 

Eradication of Guinea Worm

See the links below to learn more about the campaign to eradicate Guinea worm. The first is a link to a short article in The Washington Post: "Guinea Worm is poised to become the second human disease to be eradicated" - published August 27, 2012. The next two links describe simple water filtration devices that have played a major role in the eradication campaign.

 

Thinking.gif

Study the life cycle of the guinea worm in the table above; under what circumstances is it potentially possible to eradicate an infectious disease of humans?

 

Rogues Gallery of Other Worms that Infect Humans

The table below provides a 'rogues gallery' of flatworms and roundworms that can infect humans.

 Flatworms (Platyhelminths)

Roundworms (Nematodes)

IntestinalFluke.jpg

Intestinal fluke

ascaris.png

Ascaris

Liver Fluke.jpg

Liver fluke

Filariasis.png

Filariasis

 

 

fish-tape-worm.png

Fish tapeworm

Hookworm.jpg

Hookworm

beef_tapeworm.jpg

Beef tapeworm

pinworm.png

Pinworm

Schistosoma.png

Schistomsomiasis

trichinella_spiralis.jpg

Trichinella spiralis (Trichinosis)

Arthropods (Ectoparasites)

From the CDC web site:

"Although the term ectoparasites can broadly include blood-sucking arthropods such as mosquitoes (because they are dependent on a blood meal from a human host for their survival), this term is generally used more narrowly to refer to organisms such as ticks, fleas, lice, and mites that attach or burrow into the skin and remain there for relatively long periods of time (e.g., weeks to months). Arthropods are important in causing diseases in their own right, but are even more important as vectors, or transmitters, of many different pathogens that in turn cause tremendous morbidity and mortality from the diseases they cause."

tickmaster.jpg

Ticks

lice.jpg

A louse

This link is to an online learning module on Lyme disease