WE ALL HAVE UNIQUE BRAINS

INTRO TO PARASITES

INTRO TO PARASITES

What are parasites?

Pic: http://www.sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/food-function-and-structure/sci-media/images/cell-diagram-showing-mitochondria/379212-1-eng-NZ/Cell-diagram-showing-mitochondria.jpg
Pic: http://www.sciencelearn.org.nz/var/sciencelearn/storage/images/contexts/food-function-and-structure/sci-media/images/cell-diagram-showing-mitochondria/379212-1-eng-NZ/Cell-diagram-showing-mitochondria.jpg

Parasites are usually thought of as creatures which leech off the host and don’t give anything in

Smart Art Graphic: Original
Smart Art Graphic: Original

return, or in the worst case scenario, kill the host. This is true in some cases, however this is not always true as the above picture suggests: one of the most notable parasites of all time, mitochondria, actually has turned out to be one of the most beneficial things that has ever happened to us! (Our cells depend on mitochondria now to supply us with the energy that we need, and in return, we give them the nutrients they need to work, due to a mutualistic relationship). What matters when it comes to parasites is the relationship that it develops with the host as the Smart Art Graphic shows: it can be a true leech, but it can also develop a mutual agreement (an alliance, if you will) with the host or can get what it needs without having to harm the host. Parasites can be both microscopic (can only be seen under the microscope) and macroscopic (seen with the naked eye.)

There are multiple types of parasites, and I’ll discuss them below. In the meantime, here’s an  interesting documentary I found on Youtube regarding these creatures: Parasites Eating Us Alive!

After reading this, you may be interested to know about the different life cycles that can happen within humans: I’ve made a page regarding that called Life Cycle of Parasites. 

Types of Parasites

Pic: http://dothecoloncleanse.com/wp-content/uploads/2013/04/colon1.jpg
Pic: http://dothecoloncleanse.com/wp-content/uploads/2013/04/colon1.jpg

As the picture alongside shows, there are seven distinct types of parasites which can be seen with the naked eye. Most of them are types of worms: they include roundworms, hookworms, tapeworms, flukes and nematodes. There are also  protozoa and anthropods. I’ll refer to each one of them individually and briefly go over what they are and how they affect the human body.

 

Anthropods 

Pic: http://www.pethealth.com.au/images/paralysistick[1].jpg
Pic: http://www.pethealth.com.au/images/paralysistick[1].jpg
  • Age groups most affected:
  • Phylum: Anthropoda

There are two separate classes of anthropods: insectica, which involves bugs, lice, flies and midges, and arachnida, which includes ticks and mites. Species that you may be familiar with include pubic lice (Phthirus pubis), bed bugs (Cimex sp.)  and  scabies (Sarcoptes scabei).

 

 

Hookworms 

Pic: http://scienceline.org/wp-content/uploads/2010/12/hookworms3.jpg
Pic: http://scienceline.org/wp-content/uploads/2010/12/hookworms3.jpg
  • Age groups most affected: mothers and young children
  • Phylum: Nematode
  • Class: Secerneta

Hookworms are small worms that can infect the small intestines of mammals: they are capable of infesting both us humans and our pets. There are two common species that infect animals: Ancylostoma duodenale and Necator americanus and the type that tends to infect humans is Strongyloides stercoralis. When hookworms infect a human being, we generally don’t notice anything out of the ordinary, as it is mostly asymptomatic. The only hint that may point in the direction of hookworm infection is the patient becoming anaemic (pale and tired): this happens because, for nutrition, the hookworms suck up our iron stores in the gut. It manages to lodge itself onto our intestinal wall by using the teeth-like structures as shown in the picture above to break the mucosa (the surface layer of the intestine). In large quantities, however, the host may start developing symptoms such as fever, chest pain and coughing.

Protozoa 

Pic: http://www.discoveranimal.com/images/protozoa.jpg
Pic: http://www.discoveranimal.com/images/protozoa.jpg
  • Age group most affected: 
  • Phylum: Protozoa

Protozoa literally means ‘first animal’ and unlike most species on the planet, they are single-celled. There are multiple subphyla of protozoa: they include ameobae, flagellates, sporozoa and ciliates. Two diagnostic stages exist with protozoa and they are referred to as cysts and trophozoites: these are expelled in faeces.

Species of Amoebae 

Species of amoebae include Entamoeba histolytica, Entomaeba coli, Endolimax nana, and Acanthamoeba keratitis.

Species of Flagellates 

Species of flagellates include Giardia lambia, Dientamoeba fragilis, Trichomonas vaginalis, T. cruzi and Leishmania spp.

Species of Sporozoa 

Species of sporozoa include Cryptosporidium  parvum, Cyclospora caytaenesis, Isospora belli, Babesia microti and Toxoplasma gondii.

Species of Ciliates 

A species of ciliate is Balantidium coli.

Roundworms

Pic: http://www.valleyveterinarygroup.com/cms_media/images/roundworm.jpeg
Pic: http://www.valleyveterinarygroup.com/cms_media/images/roundworm.jpeg
  • Age group most affected: Any
  • Phylum: Nematode

Roundworms are the most common type of worm in Australia. It gets into humans by us ingesting food that is contaminated with the eggs of this worm. Species of roundworms that fall under this category include Enterobius vermicularis, Trichuris trichiura and Ascaris lumbricoides. There are multiple symptoms associated with round worms, and they include: abdominal pain, vomiting and diarrhoea, blood and/or worms in the stool, coughs and dyspnoea (shortness of breath).

Tapeworms

Pic: http://www.astrographics.com/GalleryPrints/Display/GP2104.jpg
Pic: http://www.astrographics.com/GalleryPrints/Display/GP2104.jpg
  • Age group most affected: Any
  • Phylum: Plathelminthes
  • Class: Cestoda

Tapeworms are often referred to as flatworms, and can also be called cestodes. Common species which infects humans are known as Taenia saginata and Echinococcus granulosis. They are often contracted by people eating undercooked pork or fish. These tapeworms lodge onto the intestinal wall as a larva via their hooks, and then they can grow massive (up to metres in length), taking all the vitamin B12 it can handle. In addition, tapeworm cysts can end up in the bloodstream and manifest themselves in the brain, leading to cysticerosis.

Fluke Worms 

Pic: http://www.thelifetree.com/images/flukes05.jpg
Pic: http://www.thelifetree.com/images/flukes05.jpg
  • Age group most affected: Any
  • Phylum: Plathelminthes
  • Class: Trematoda

Fluke worms are examples of flat worms, and they have a tendency to be leaf-shaped. Examples of fluke worms include Schistosoma sp. Fasciola hepatica, Clonorchis sinensis, Paragonimus westermani, Heterophyes heterophyes and Brachylaima cribbi. They all exhibit a two stage life cycle: with a definitive and an intermediate host. To learn more about life cycles, you can find information at Life Cycles of Parasites. There are two groups of flukes, known as tissue flukes and blood flukes. Tissue flukes tend to infect the bile ducts and the lungs and blood flukes such as Schisotsoma infect the blood.