Gross Human Parasites IV - Sparganosis for the Flesh-Lover

Keeping pets at home? Love sushi? Enjoy frog-congee? 

Sparganosis is a parasitic infection, the culprit is a type of tapeworm belonging to the genus Spirometra. Mammals such as dogs, cats and raccoons are the definite host (final host) of the parasites. 

Copepods, Frog, Cat. (The first, second and definite hosts)

The adult Spirometra living in the intestines of their hosts lay uncountable eggs which discharge during hosts' defecation. The eggs are then consumed by copepods, the first intermediate hosts; amphibians such as snakes and frogs preying on copepods are the second intermediate hosts. Within the first intermediate hosts, the eggs hatches and the larvae live in the body cavities of copepods; after passing to the second intermediate hosts, the larvae continue to proliferate and penetrate into the muscles and subcutaneous tissues of the hosts. The second intermediate hosts of this parasites are eventually consumed by wild carnivores such as dogs and cats, and the parasites mature in their definite hosts and complete their life-cycle. 

And how do human get Spargonosis? 

Human are actually the accidental hosts of Spirometra (or maybe not accidental). 

• consumption of raw water from rivers or lakes 
• open wounds on body contacted with Spirometra sources such as animal feces or raw flesh 
• consumption of uncooked or not-fully-cooked flesh 

Once infected, the parasites will move to various organs such as eyes and brains of the patients or subcutaneous tissues in various body parts. No symptoms will be seen from the beginning, and eventually as the parasites grow, bulges (nodules) will develop on the infected regions along with pain. For infection in the eyes, patients' eyes will bulge out. For infection in the brains, neurological symptoms such as loss of motor control can occur. 

A boy with ocular Sparganosis
Source: click here

Surgical removal of adult Spirometra from eye. 

It has been reported in China rural areas that villagers believed in old traditional methods of applying raw frog flesh to wounds to speed up recovery, and thus resulted in being infected by Spirometra. Majority of human Spirometra infection cases occur in Japan, Korea and China.

Retracting an adult Spirometra from a frog.

Antibiotics have been given to patients infected with Spirometra, however this is not really beneficial as a cure. The best way to get rid of the parasites is through surgery. 

The Ultimate Body Invaders

In the world of Nature, every organisms are trying very hard to win the game of survival. In order to win the game, some come up with an extraordinary method---to invade another kind and manipulate the host to create a condition favoring the survival of the invaders, while putting the hosts in great danger. The following are 5 ultimate body invaders that adopt the unique mechanism to ensure the survival of their species. 

Cordyceps 

Cordyceps invaded host. 

Cordyceps are fungi from the genus ascomycete fungi, among which there are a lot of different species. The fungus parasites on insects and different species parasites on different hosts. As the cordyceps fungus infects an insect host, its mycelium (fungus part) replaces the host's body tissues. The fruiting body of the fungus will eventually puncture the host body and protrude out to allow the release of ascospores (spores). Many of the times, during the development stage, the fungus manipulate its host such as controlling the insect to climb up a plant and attaches itself there before it dies, ensuring optimal dispersal of the spores of the fungus. Some cordyceps genus are proven to have medicinal properties.  

Paragordius tricuspidatus

Parasitic worm emerging out of cricket.

Paragordius tricuspidatus is well-known for manipulating behaviour of its cricket host. The eggs of this parasitic worms are laid at the river edges where the crickets reside. The microscopic size eggs are ingested by accident by the crickets, and hatch within. The larvae of the worm get nourishment from the host and grow, eventually filling the entire body cavity of the cricket. They can grow up to 10 - 15cm in lengths.  Upon maturation, the parasitic worms are ready to exit the hosts, the worms will induce an abnormal behavior to the cricket hosts --- to jump into the water. Most of the crickets will drown, while some will survive and lead a normal life after the excision of the parasites. After which, the worms will slither out and find its mating partners. The manipulation in behaviours are believed to be cause by a release of proteins that affect the Central Nervous System (CNS) of the crickets.  

Dinocampus coccinellae

Paralyzed ladybug guarding cocoons

Dinocampus coccinellae is a species of wasp that parasites on Ladybug. The female wasp lays one egg in the soft abdomen of the ladybug. After the egg hatches, the larva starts to consume the ladybug's eggs, then the gonads and the body of their host. However the ladybug host is still alive. When the parasites are ready to emerge, they paralyze the ladybug and tunnel out of its body. Then the parasites pupate in a cocoon attaching to the leg of the living ladybug, The ladybug's occasional twitching ward off any potential preys of the parasites,  making the ladybug the "bodyguard" of its parasites. A few days later, the wasps will emerge from the coccoon. 1 out of 4 ladybugs will recover from the paralysis and come back to health after all the cocoons have emptied.  

Leucochloridium paradoxum

Snail with infection.

Leucochloridium paradoxum, a kind of parasitic flatworm, infects a snail and alters the original behaviors and appearance of the snail; after which increasing the chances of the snail being eaten by a bird which is the next and final host of the parasite. To do so, the parasite resides into the translucent eye-stalks (preferably left one) of the snail, altering the normal eye-stalks into yellow-greenish stripes, inducing caterpillar mimicry. Birds do not usually snack on snail, however the altered eye-stalks of the snail, resembling a caterpillar results in birds mistakenly consuming the infected snails. The parasites also cause the snail to be more visible to the birds by making the snails stay under the sunlight instead of hiding in the shade.   

Myrmeconema neotropicum

Normal ants.

Infected ant with red gaster raise up high to mimic wild-berries. 

Myrmeconema neotropicum is tetradonematid nematode parasite that induce berries mimicry in tropical ants. The parasites mate and lay eggs inside the gasters (the hindmost abdomen) of the ants. The infected ants will develop bright red, egg-filled gasters that resemble red berries available in tropical forest. The parasites also cause the weakening of the exoskeleton linking the gasters to the rest of the body of the infected ants. The infected ants will walk with their gasters raise up high, allowing birds to mistaken them as wild berries and pick up the gasters which detach easily from the ant.The parasite eggs will be passed in the birds' dropping and later collected by the tropical ants again.  

Care For Your Pets - Roundworms in Dogs

Do you have a family dog at home? If your answer is yes, this is a post you might be interested to know more about parasites that might live within your dogs.

Roundworm is the most common kind of infectious parasite in puppies and dogs; if not treated, roundworm infection in puppies can be fatal.

The Dog Roundworm, Toxocara canis, lives within puppies and dogs and the adult worm is ranging from 9 to18cm (about 3.5 to 7 inches) in length. A female can lay about 200,000 eggs of microscopic size daily. The eggs are protected by thick cell wall and can survive for months in the soil. These make roundworm infection highly transmittable among dogs.

There are several ways puppies and dogs can get roundworm infection. For puppies, prenatal infection is the most common type, whereby the roundworm larvae from the mother dogs migrate into the placenta and infect the developing puppies before birth. On the other hand, puppies can get infected through ingestion of mother’s milk that contains roundworm eggs. Puppies and dogs can also get infected by ingesting eggs in the soil, this is the most frequent route of infection in adult dogs.

Life cycle of roundworm in puppies (of age up to 3 months):

• Step 1: Roundworm eggs ingested by the puppies (through milk or from soil) enter the stomach and then hatch in the small intestines.    
• Step 2: The larvae travel through the bloodstream and enter the lungs and liver of the pup.
• Step 3: After residing in the lungs, the larvae move their way up the windpipes and are swallowed by puppies. 
• Step 4: The larvae develop into adult worms in the intestines, completing their life-cycle. The adult worms mate pass eggs into the faeces of puppies. (Fortunate to mention that the eggs in the faeces will only become infective after 3 to 4 weeks of incubation in the soil)     

Roundworms in stools
Picture source: click here

For older dogs, they have developed immunity against the roundworm, therefore very few larvae will be able to complete their life cycle within the dog. If any larvae completed the life cycle, the adult worms will reside in various body tissues in the dog, and develop a tough shell (encyst) that protects them against the host’s immune system. At this stage, even the de-wormer might not be able to kill the worms. However, during pregnancy, the encysted worms get activated again and migrate to the placenta to infect the next generation.

In adult dogs, roundworm infection can be no symptom at all; while in puppies some symptoms might be vomiting, diarrhea, dull-coat and bloated belly. Worms might appear in the vomit and the feces, which look like white threads or white spaghetti strands that wriggle.
In general, an infection of roundworm can be gotten rid of with the use of de-wormers prescribed by vet, and your doggy will be back to health in no time! HOWEVER, severe infection in young puppies can be fatal, and roundworm infection is not only contagious among dogs, there are risks whereby roundworm transmits from dogs to human. Be warned!

For more information on roundworms in Human, click here: Roundworm in Human

Living with Elephant's Body Parts

The "Elephant-syndrome", elephantiasis, by the name of it, patients develop thickening of skin and and underlying tissues (resembling the elephant's trunks) in the body parts. The areas of thickening of skin and tissues can occur in face, legs and even male genitals. The disease results in the affected body parts to swell up to the size of a fist or head. The abnormalities triggered by the disease not only lead to great inconvenience in the patients' daily lives, and also agony in the patients.

Extreme case of lower limb swelling.

The disease is initiated by thread-like parasitic worms with Wuchereria bancrofti being the most common cause, and is transmitted by mosquitoes. As the mosquito sucks blood from a human, it introduces the larvae of the parasitic worms which will travel to the human lymphatic system and develop into adult worms to a length ranging 1 to 4 inches. The worms will be living within the infected person for years (usually about 7 years), the longest ever recorded is 40 years.

A woman with enlarged arms.

The sexually matured worms will mate and release millions of microscopic larvae into the blood stream. As the adult worms live within the lymphatic, obstruction of the vessels will lead to swelling, especially in the lower body especially the legs and the genital areas. Therefore, the parasites, as well as the body immune system, contribute to the development of elephantiasis which takes years to show. On the other hand, the disease may develop without being infected by the parasites.

Picture source: click here

The picture shows an enlarged scrotum, affected about 4% of the infected males.

It has been evident that if a pregnant woman got infected by W. bancrofti, her child will have the chance to be infected as well. This can be explained by the parasite's antigens being passed to the fetus' blood circulation. Another scenario will be the fetus becomes tolerant to the parasites' antigens. In future, parasite infection (of the same antigens as the one presented in fetus stage) will be able to evade the host immune system of that child and leading to the development of elephantiasis more easily.

Currently, the medication available is only able to kill the adult worms within the lymphatic system, while the larvae not responsive to treatment.

The Body Invader - Bodyguard for Enemies

I have come across a video clip from National Geographic program which is really interesting. However, the video may look gross to those who hate or have phobia of caterpillars. Watch at your own risk．＝）

A wasp had laid its eggs into the body of a catepillar. The larvae hatched and grew inside the catepillar body, feeding on their host's blood. As they grew larger, they broke out from the catepillar skin using their tiny saw-like teeth!

The catepillar is not dead yet, at that moment. The larvae of the wasp then spinned their own cocoons. The poor catepillar will then start to act as a body guard protecting the wasp larvae until it eventually starves to death.

The wasp larvae not only parasitised the catepillar, they manipulated the behaviours of their host to protect them through the pupa stage when they were vulnerable to other predators! The poor catepillar protected its enemies till the end of its life.

Gross Human Parasitic Worms III - Roundworms

In the previous post, I have mentioned one of the parasites in human's digestive tract, the Tapeworm. In this post, another kind of human parasite, Roundworm, will be discussed.

Ascaris is a type of parasitic worm known as the Giant intestinal roundworm. This type of parasite infects human living in areas with poor sanitation. Roundworm is the most common type of human parasites worldwide, and its infection is named Ascariasis.

Roundworms live in the small intestines. The females can grow up to 40cm in length, weighing 9g and produce over 200,000 eggs everyday!

When Roundworm eggs are ingested, they will hatch in the intestines and burrow through the intestine walls. After that, they make their way to the heart, the lungs and finally break out into the alveoli as shown in the diagram below.

If large amounts of roundworms accumulate in the body, it will result in the blockage of intestinal tracts. At this stage, patients will feel intense abdominal pain. To examine if a person is infected with roundworm, stool sample can be send to examine and suspected cases can undergo an abdominal X-ray. In some cases where the blockage of intestine is too severe, surgery is required to get rid of the worms.

For more information of roundworms in your pets, check out: Roundworms in Pets

Gross Human Parasitic Worms II - Tapeworms

For as long as human exists on the Earth, there are many organisms that feed off, reside in, seek shelter from the human body.

In this post, the most common type of parasitic worm that reside in the digestive tract of a human. The tapeworm.

Tapeworms larva can be ingested by eating uncooked or undercooked meat. After the larvae arrive at the intestines, they will start to grow into adult tapeworms that can be as long as 30m (fish tapeworm), 40m (beef tapeworm)and 120m (some other species of tapeworm)!

And what's the most horrible part? When a person has tapeworm infection, there will be definitely more than one of those in the digestive tract. These intestine intruders, when at adult stage, lay millions of eggs each day! Just imagine that, the whole intestines of yours filled with those slippery wrigglers, it will sure send chills down your spine.

How does the tapeworm attach to the intestines?

Tapeworms have sharp hooks on one side of theirs heads. Those hooks drill into the lining of the intestines and simply provide anchor for the tapeworms.

Tapeworms are usually found on meat products, thus high protein diets are not good for a healthy life. Diet high in fiber is a good prevention against these disgusting worms, as dietary fiber promotes regular bowel and clears off these parasites from the intestine.

Gross Human Parasites I - The Guinea Worms

Guinea worm is the common name for Dracunculiasis, which thrives in some of the third world countries where clean water supply is not available.

If this worm is new to you, you may start to wonder what does the worm look like?

The answer is: Guinea worm looks exactly like a spaghetti noodle at mature stage (sorry to spaghetti lovers ) It can grow up to more than 90cm in length.

How do people get infected?

Well, at places where clean water is not accessible, people can get infected while drinking stagnant water that hosts tiny water flea that carry the larvae of Guinea worm. Once inside the stomach, the larvae take 1 year to mature and pierce through the walls of intestines to mate. The males will die after mating where the female worms burrow into the deeper connective tissues and attempt to leave the human host (usually through the lower limbs).

At this stage, as the Guinea worms try to burrow their ways out of the human hosts, painful blisters are formed on the human skin. The pain is excruciating with a burning sensation, human hosts often soak their limbs in cold water to ease the pain.

Once the blister or open-sore submerge into water, the female Guinea worms will take their chance and release thousands of larvae. The water flea will consume the larvae, and another cycle will begin.

Currently, there is no cure for Guinea worm disease. To remove the Guinea worm from a human host, one must wrap the worm in a stick once the worm emerges from the skin. Then, slowly, bits by bits, wound the worm around the stick by pulling the worm out of the skin. The whole process is long and painful, sometimes it might take more than 1 month just to extract the worm out of the body. (the worm is very long and is buried deep in the connective tissue)

I dare you to read this post while eating spaghetti. *EviL grin* 

You may NEVER want this 'Tongue' - Cymothoa exigua

At the first sight, many people may find this little parasite adorable (or is just me?). In the above image, Cymothoa exigua (yes, this is the creature's scientific name), looked exactly harmless, so tiny and cowardly hiding in the mouth of a fish.

However, in the view point of the host, this is totally NOT a pleasant experience. So, what harm can the little creature inflicts?

Guess it?

Cymothoa exigua is the first known parasite that replaces hosts' body parts upon parasiting. In this case, is the poor fish's tongue.

This little creature enters a fish mouth through the gills. Discovers its way to the tougue and attaches itself to the base of the tongue. After that, it happily sucks blood from the veins on the tongue using claws on its 3 pairs of legs at the front.

A fully grown Cymothoa exigua can be up to 3 to 4cm in length. Imagine the amount of blood it will need (also think of the size of the tongue of the fish). Eventually, the tongue withers due to lack of supply of blood and shrink till it loses its original function.

Cymothoa exigua is not that cruel to let the fish carry on its life without a tongue. As a result, the little parasite replaces itself as the tongue of the fish by attaching to the muscles of the tongue stub. Interestingly, the fish can freely use its "new tongue" at its control.

In the mean while, Cymothoa exigua survives by either the blood of the fish or the mucus of the fish. Other than having a whole new tongue, the creature does not inflict any other damage to the host fish. An extra tongue, anyone?