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Wellcome Image of the Week: Dog Tapeworm

30 Aug, 2013

Dog tapeworm

It might look like a beautiful flower, but this image of the week is more the stuff of nightmares! The picture above shows a dog tapeworm (Taenia pisiformis) taken using a light microscope. The image clearly shows the hooks of the tapeworm on its head (scolex), which it uses (along with four suckers) to attach to the small intestine of canids like dogs and foxes.

The image was taken by Spike Walker. The tapeworm was on a microscope slide, giving it a slightly squashed look. The muscle and other tissue of the tapeworm were stained red, but the hooks (made of chitin) don’t stain. Therefore, Spike used a contrast enhancement technique called Rheinberg illumination, which gives the hooks their bright colours against a blue background. First demonstrated over a hundred years ago by Julius Rheinberg, this involves using coloured filters so a transparent sample can be seen.

These tapeworms can grow up to two metres long, with a very simple nervous system and no digestive tract, absorbing nutrients directly through their outer layer. They are long and flat, made up of thousands of segments called proglottids. These proglottids contain a complete reproductive system and can contain thousands of eggs. When mature, the proglottid breaks off from the tapeworm and is excreted by the host in faeces. It then ruptures and releases its eggs to infect another animal.

When a rabbit eats grass contaminated with these eggs, the eggs hatch in the rabbit’s stomach to form ‘6-hooked embryos’ which claw their way through the gut wall and develop into ‘larvae’ known as bladder-worms. Dogs become infected with Taenia pisiformis after eating rabbits that have been parasitized in this way.

Image credit: Spike Walker, Wellcome Images

Wellcome Images is one of the world’s richest and most unusual collections, with themes ranging from medical and social history to contemporary healthcare and biomedical science. All our images are available in digital form so please click the link above if you would like to use the picture that features in this post, or to quickly find related ones. Many are free to use non-commercially under the terms of a Creative Commons licence and full details of the specific licence for each image are provided.

Make us gasp with your images! We are always on the look out for striking images so if you are a research scientist, clinical photographer, or illustrator and have high quality imagery that relates to biomedical science or contemporary healthcare, we would love to see your work. Our collections span all artistic media and imaging techniques ranging from hand drawn illustrations to functional magnetic resonance imaging (fMRI) scans. What’s more, any images we receive before 30 September 2013 will be considered for the Wellcome Image Awards 2014. Email Sabrina Taner for more information about this.

One Comment leave one →
  1. jhn bernard permalink
    7 Oct, 2015 6:41 pm

    nice article thank you

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