Impurest's Guide to Animals #145 - Lancet Liver Fluke

And it looks like Shocktober is up to even more sinister events, between computer crashes, a mystery virus (biological) and a near miss with a scorpion, life has become a little too creepy. Last week creepiness was combined with crawliness in the form of the Waterfall Centipede. This week the worms return for a seasonal assault on everything good and decent, hope you guys enjoy.

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Issue #145 – Lancet Liver Fluke

Kingdom – Animalia

Phylum – Platyhelminthes

Class – Trematoda

Order – Plagiorchiida

Family – Dicrocoeliidae

Genus – Dicrooelium

Species – dendriticum

Related Species – Lancet Liver Flukes are among a group of flatworms known as Trematodes that infect multiple species of mammal when in their adult form (1)

Range

Not Just a Fluke!

Lancet Liver Flukes are microscopic parasitic flatworms that infect multiple different hosts as they mature. While similar in appearance to the Chinese Liver Fluke (Clonorchis sinensis), the Lancet Liver Fluke can be distinguished by a lobbed testis at the front of the animal, next to a large oral sucker that siphons blood out of living cell tissue. The initial hosts for the Lancet Liver Fluke are land snails (2), which accidently consume the eggs of the flatworm, triggering them to hatch when in the molluscs gut, with the larvae drilling into the gut wall where it develops into a ‘juvenile form’ ready to infect its intimidate host.

Eventually, upon maturation, the Lancet Liver Fluke is expelled from its host, in slime covered cysts, created by the snail to reduce the irritation suffered from its parasitic infestation. These slime covered cysts are then eaten by ants, and upon entering the insects gut, the parasites diffuse into the blood stream, finally attaching into the cluster of nerve cells under the oesophagus. From there the fluke waits until the temperature drops before taking control of its host, forcing it to leave the nest and climb to the top of a blade of glass, clamp on with its mandibles and wait. Upon the return of the sun, should the worm not have achieved its goal, it send its host back to the nest ready for a day of normal ant behaviour.

Night after night, the fluke takes control until it encounters its final host, usually a cow (Bos taurus) although any large grazing animal will do (3), which eats the grass including the ant clamped to it and its parasitic cargo too. When inside the cow, the fluke moves to the liver where it matures, and then breeds with other worms (each Lancet Liver Fluke is a hermaphrodite) before laying eggs ready for dispersal in the host’s dung. Lancet Liver Flukes can infect humans, should they eat undercooked cow liver, but as with the cow is usually quite mild, resulting in anaemia, diarrhoea and some bloating, although large infections have been linked to cirrhosis of the liver.

CSI Ecology: The Case of ‘Hoppy’ the Frog

So for this week I decided to do something a little different, instead of invasive species, animal poisons or endangered species I decided to give you guys something a little more interactive. You are being tasked with placing the clues, show down below, to figure out what happened to the victim, and what or who is responsible for it. Hope you guys enjoy and drop your answer in the form of a comment, the correct answer will be revealed next week.

The ‘Victim’

The Victim is an adult Leopard Frog (Lithobates pipiens), as evident the animal has extra limbs caused by an unknown source. A cursory examination of the ‘crime scene’ shows that other species of frog, toad and newt all have deformities to their limbs, ranging from slightly reduced limb length to full blown extra limbs. In addition to the mutations, the amphibian population, including those with seemingly normal features seems to be weaker than populations in neighbouring ponds, due to an unknown infection.

The ‘Crime Scene’

The Crime Scene is a small pond in Minnesota found on the edge of a wooded park with a small stream running through the water body. Visible human pollution is low, and there is no heavy metal contamination in the water. Organic pollution, particularly nitrates and phosphates, is higher than average, but not at a level that would cause mass eutrophication. Radiation levels are consistent with background levels for the area.

‘Witnesses’

In addition to the infected amphibians there is plenty of wildlife using the pond and connecting stream. On the shore there are animals associated with water bodies such as ducks, herons and water snakes. In the water itself there are small fish, water snails, plenty of aquatic insects and most importantly normal looking tadpoles. It has been noted that the number of frog predators in the area has increased, although this may be a secondary effect of the mutations to the limbs making them easier to catch.

Microscopic analysis of the water content shows the usual spectrum of aquatic plankton such as snail larvae, diatoms, freshwater shrimp, flatworms etc. At current there is no sign of the frog chytrid fungus (Batrachochytrium dendrobatidis) in the water which decimates amphibian populations in areas where it is found.

Suspects

After much detective work we’ve narrowed down the cause of these odd mutations to one (or more) of the following causes;

a) The mutation is genetic caused by a restricted population inbreeding with each other

b) The mutation was triggered by a sudden increases in radiation

c) Organic pollution caused genetic damage to the larval amphibians reducing their immune response and causing mutation of the limbs

d) The mutation is triggered by fish and tadpoles biting the limbs of adult frogs, causing their limbs to regenerate in odd ways

e) A trematode flatworm infiltrated the limb buds of a tadpole and caused genetic damage to the developing leg

f) A disease carried by birds from pond to pond is attacking the frog’s immune system causing excessive limb mutation

g) The amphibians were modified in a human lab and released back to the wild

Bibliography

1 -www.arkive.org

2 - Krull WH, Mapes CR (October 1952). "Studies on the biology of Dicrocoelium dendriticum (Rudolphi, 1819) looss, 1899 (Trematoda: Dicrocoeliidae), including its relation to the intermediate host, Cionella lubrica (Müller). VII. The second intermediate host of Dicrocoelium dendriticum".The Cornell Veterinarian.42(4): 603–4.

3 - Ekstam B, Johansson B, Dinnétz P, Ellström P (November 2011). "Predicting risk habitats for the transmission of the small liver fluke, Dicrocoeliumdendriticum to grazing ruminants". Geospatial Health. 6 (1): 125–31

Picture References

1 - http://www.reed.edu/biology/professors/srenn/pages/teaching/web_2010/GMKlancetliverfluke/images/LancetLiverFluke2.jpg

2 - http://www.reed.edu/biology/professors/srenn/pages/teaching/web_2010/GMKlancetliverfluke/images/LLFdistribution.jpg

3 - http://bugguide.net/images/raw/LQA/RFK/LQARFK9RFKURZQYQ503QFKVRHQ1RIQTR60CQM0YQZQVR40YQW00040TQ3KOQ70R0N0ORKQFR0Q3RN0.jpg

4 - http://www.wanderingherpetologist.com/wp-content/uploads/2012/06/deformed-frog-110425.jpg

Looks like things are more than a wee bit freaky when lancets are involved. Next week we meet an animal that kills sharks…from the inside?! Until then make sure to critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese

Want more IGTA? Talk about some weird worms, for something equally weird why not check out the creepy Hammerhead Slug. Or for something even more sinister then what’s shown here, why not check out the harbinger of terror known only as the Bobbit Worm.

@cbishop, @ostyo, @wildvine, @laflux, @black_wreath, @galactic_1000, @anna_karenina,@heroup2112, @blueecho, @jamiewolfe7, @bb_ryder, @destinyman75, @xlr87t3, @xwraith, @pipxeroth, @juiceboks, @mikesterman, @mass_fantasy and @amendment50

Success isn't just a fluke

@impurestcheese: I'm pretty sure Its (e) :).

I did a freshwater ecology course in my zoology degree, and double checked on the internet to be sure so it feels kinda hollow tbh :p. Great work as always

Umm, I'm going to say d)...

I'd say e)

@black_wreath: @youngkaiser: Cool thanks for your answers

@laflux: Cool thanks, hopefully you'll be pleasantly surprised by the answer

C

I can only guess, but "e."

Going to say C. Wouldn't be surprised if it was something unexpected like F, though.

@ficopedia: @pipxeroth: @spareheadone: Cool thanks for your answers guys, all will be revealed soon

C'mon gimme the answer

@spareheadone: You'll find out tomorrow. Today I'm enjoying ComicCon

On one hand, I can't help but admire successful parasitic behaviour yet on the other, I am thoroughly horrified.

I already knew the answers from having read the next blog following this one earlier, but I would have guessed e). What a freaky frog. Poor thing.