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. 

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 Sleeping Beauty Syndrome

Human African trypanosomiasis, also known as the sleeping sickness, is a vector-borne parasitic disease. Sleeping sickness is caused by protozoa of 2 organisms from the Trypanosoma Genus - namely the Trypanosoma brucei rhodesiense and Trypanosomoa brucei gambiense.

T.b.rhodesiense - infection emerges in a few weeks and is more virulent and faster developing as compared to T.b.gambiense. (10% of the reported cases of sleeping sickness)

T.b.gambiense - results in a chronic condition which can extend in a passive phase for months or years before symptoms emerge. When the symptoms show up, the patient is already in an advanced disease stage where the central nervous system is affected. (90% of the reported cases)

Causes

Tsetse flies act as a vector of the Trypanosoma. Tsetse flies are infected when they consume blood from infected people, the parasites enter the midgut of the fly and multiply in the salivary glands.

Infected Tsetse flies go around biting people, leaving behind red, painful swollen wound when they inject the parasites into the skin tissue. The parasites will then enter the lymphatic system and pass into the bloodstream.

Symptoms of the disease

General

• Anxiety
• Drowsiness
• Fever
• Headache
• Increased sleepiness
• Swollen lymph nodes

Patients often feel very sleepy in the day but have difficulty sleeping at night and this gives the

disease it's name.

Infection

• Mother-to-child infection occurs when the trypanosome cross the placenta barrier and infect the fetus.
• Accidental infections have occurred in laboratories due to pricks from contaminated needles.

If no treatment provided, Sleeping sickness is 100%

fatal!

Screening

Diagnosis must be made as early as possible before the neurological system is affected

to reduce complications.

Microscopic observation of:

• Blood smear
• Lymph node aspirates
• bone marrow
• Cerebrospinal fluid tests (in the later stage of the disease)

Treatment

• Melarsoprol - used for both forms of infection. It is derived from arsenic and can be fatal to as much as 10% of the patients taking the drug.
• Eflornithine - effective against T.b.gambiense. Less toxic, alternative for Melarsoprol.
• Pentamidine - used for the treatment of 1st stage of T.b.gambiense infection. However, it can cause toxic or allergic side-effects.
• Suramine - treatment for the 1st stage of T.b.rhodesiense infection. Side effects in urinary tract and allergic reaction.

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*