Onchocerca volvulus

By, Sarah Smith

The Onchocerca volvulus is a worm that causes Onchocerciasis, also known as “River Blindness.” This nematode has a fascinating and devious way of reaching its only host, humans. They infect and then mature inside a Black fly, and when it bites a human, they are transmitted through the fly’s saliva to the host’s skin, where they reproduce in the muscle fibers. If they reach the eyes of the host, which they commonly do, they can cause permanent blindness, commonly referred to as “river blindness” in Africa.

Anatomy:













Form and Function:
Onchocera Volvulus begins its life cycle when a female black fly drinks the blood of a human. The parasite, which is found in the dermis of the human, is consumed by the fly. The parasite then chews through the gut of the fly and relocates in the thoracic flight muscles of the fly. At this point, it is in its first larval phase. It stays there until it matures into the second larval phase, and then moves to the saliva of the fly. When the fly drinks the blood of a human host, the O. volvulus passes into its bloodstream. Next, the larvae moves to the subcutaneous tissue. Here, they form bumps, called nodules, and mature into fully developed, adult worms. This developmental period lasts between six to twelve months. Once fully matured, they mate, and can reproduce at a rate of between 1,000 to 3,000 a day. These eggs remain in the subcutaneous tissue, until picked up by a black fly, when they begin the cycle again. The adult worms, however, migrate to the skin and connective tissue of their host.


Impact on Humanity:
The Onchocerca Volvus causes a disease called Onchocerciasis. Onchocerciasis is most commonly transmitted in Guatemala, Ecuador, Mexico, Colombia, Venezuela, Brazil, Yemen, and thirty countries in Africa. People get infected when in frequent contact with black flies. Blindness almost always results from infections, as well as rashes and bumps under the skin. Onchocerciasis used to be one of the leading causes of preventable blindness and skin diseases in the word. World Health Organization, however, has dramatically reduced the impact of the disease by leading disease control programs. These programs introduce a drug called Ivermectin, which is taken orally and heals the disease entirely. Because of this being donated around the world, the impact of Onchocerciasis has dramatically decreased throughout the years. The prevention of Oncerciasis is simple: wear insect repellent. However, many countries do not have access to this. Unfortunately, there are no vaccinations yet invented that prevent the disease.

Journal/ Article Review:
This article is about the Onchocerca Volvus, and talks about how scientists have yet to create a vaccine against its infection. They have used molecular tools to identify the antigens that may help prevent development of the disease, yet are unable to come up with a vaccine to prevent the disease. This article talks about different attempts and ideas of how they can create a vaccine to prevent Onchocerciasis.

Works Cited:
• Nettleman, Mary. "Onchocerciasis." eMedicine. N.p., 04/16/2009. Web. 13 Oct 2010

• "Onchocerciasis (River Blindness)." Medic8. N.p., 09/11/2004. Web. 13 Oct 2010

• "Neglected Tropical Diseases." Plos. The Onchocerca volvulus Cysteine Proteinase Inhibitor, 11/18/2009. Web. 13 Oct 2010. .


Photos Retrieved From:

• "Onchocerca Volvus Lifecycle." Wikipedia. Wikipedia Commons, n.d. Web. 14 Oct 2010. .

• Cummings, Varki. "Nematoda." Essentials of Glycobiology. The Consortium of Glycobiology Editors, 2009. Web. 14 Oct 2010. http://www.google.com/imgres?imgurl=http://www.ncbi.nlm.nih.gov/bookshelf/picrender.fcgi%3Fbook%3Dglyco2%26part%3Dch23%26blobname%3Dch23f1

The Crown of Thorns- Jacque Prado

Figure 1

I. Introduction:

The crown of thorns is not like any other sea star, it is the second largest sea star in the world, and resides mainly in coral reefs around the Red Sea, Pacific Ocean, and Indian Ocean. It is a nocturnal sea star that travels alone. It keeps much distance between themselves and other sea stars of its species. It feeds mainly on living coral and can consume up to 6 meters of it a year. They are venomous and can cause great damage to our coral reefs.

II. Anatomy:

The crown of thorns, also known as the Acanthaster planci, can be grow up to 80 centimeters in diameter. Most sea stars have only 5 arms, but the crown of thorns can grow up to 21 arms that extend radially from the body. The arms are covered with venomous spines that can pierce through skin and some clothing with barely any pressure. They have tube feet, which are located underneath the arms, which allow the crown of thorns to move around and can help them to open food such as mollusks.

figure 2

figure 3

III. Form and Function:

The crown of the thorns prey only on live coral, unlike any other sea star. Sea stars have two stomachs, the cardiac and the pyloric. They turn their cardiac stomach inside out through their mouth to cover the coral and then digest it with enzymes. The pyloric stomach is located inside the body and is what gets the partially digested food. It will eat everything up until the calcium carbonate skeleton. Their food is then digested and released from the anus. They reproduce, by what is called spawning. A female crown of thorns can reproduce up to 100 million eggs a year. Through their pores, they eject sperm and eggs into the water, which meet and then fertilize. Due to the fact that the crown of thorns is covered with many venomous spines, it does not have many enemies. They do have a few, such as the triton’s trumpet, painted-prawns, Napoleon wrasse, and the green triggerfish. Though they have a few predators, it does not affect the survival of the crown of thorns.

figure 4

IV. Impact on the World/Humanity:

The crown of thorns multiply quickly not only because they have few predators, but also because if dismembered, they can recreate another sea star from the severed limb. Since there are so many of them and because they eat only live coral, they are being blamed for the destruction of coral reefs. Although, some ecologists say that the crown of thorns are actually helping prevent over population and encouraging coral reef biodiversity. They say this because the crown of thorns eat the faster growing coral which prevents them from over powering the slower growing ones.

V. Journal Article Review:

This is article is mainly about how the crown of thorns can have a good and bad effect on coral reefs. It has a good effect on them by increasing diversity on the coral reefs by not allowing one species to overgrow. While on the other hand, it can cut down coral population by 90%. Ecologists are trying to find ways to decrease the number of crown of thorns in the ocean. They have tried things such as burying them on shore and injecting them with poison. They are still trying to come up with better ways to deal with them.

figure 5

Video Website:

http://www.oceanfootage.com/stockfootage/Crown_Thorn_Sea_Star

Works Cited:

"Asterozoa: Fossil Groups: SciComms 05-06: Earth Sciences." Palaeobiology and Biodiversity Research Group, Department of Earth Sciences, University of Bristol. Web. 15 Oct. 2010. .

"The Crown of Thorns." Community Environmental Research in the Pacific Islands. Web. 15 Oct. 2010. .

"Crown of Thorns." ReefED - Educate to Keep It Great. Web. 15 Oct. 2010. .

"Crown-of-thorn Sea Star." Encyclopedia of Earth. Web. 14 Oct. 2010. .

"Crown-of-thorns Starfish." Wikipedia, the Free Encyclopedia. Web. 14 Oct. 2010. .

Pictures:

Figure 1: http://www.bubblevision.com/underwater-pictures/racha-noi/images/crown-of-thorns.jpg

Figure 2 & 3: http://www.bubblevision.com/underwater-pictures/racha-noi/images/crown-of-thorns.jpg

Figure 4: http://siera104.com/bio/echin.html

Figure 5: http://www.solcomhouse.com/images/lg_Crown-of-thorns_starfish.jpg

Hymenolepis nana - The Tapeworm

I. Introduction


Kingdom: Animalia
Phylum: Platyhelminthes
Class: Cestoda
Order: Cyclophyllidea
Family: Hymenolepididae
Genius: Hymenolepis
Species: Nana

The species, Hymenolepis nana, which I chose to do my project on, is in the phylum Platyhelminthes. Like all Platyhelminthes, H nana if acoelomate, triplobastic, protostomic, and lacks a respiratory, circulatory, and skeletal systems.
H nana is completely parasitic and has to rely on its host for nearly everything. Over the course of their lifespan, tapeworms tend to have more than one host. However, an adult H nana will typically spend its life in the intestine of its host. If infected with a tapeworm, the host could suffer and lose weight quickly. The lifespan of a tapeworm can be up to twenty years! I chose H nana because it is the most common tapeworm found in humans, especially small children. Its main habitat is in temperate zones and it can be found in nearly all cosmopolitan areas. In fact it is named by some scientists as the cosmopolitan tape worm.





II. Anatomy




The anatomy for H. nana is rather simple. H. nana has no external cilia or any other kind of locomotive organ. The head of the tapeworm is called the ‘scolex’ and it contains six hooks to attach itself to the host’s inner intestine. Behind the head are multiple reproductive organs. The scolex of the tapeworm has no eyes or mouth because it does not need to see or eat.





III. Form and Function

H. nana lacks a digestive system. Instead the tapeworm directly absorbs food and nutrients from the host. On the surface of the tapeworm are a multitude of tiny wrinkles which greatly increases the surface area of the tapeworm and therefore allows more food to enter.
The excretory function of H. nana is like other Platyhelminthes. Metabolic waste is mostly diffused through the body wall.
The reproductive units found behind the scolex are called ‘proglottids’. Tapeworms are hermaphrodites because the proglottids have both female and male reproductive organs. H. nana can reproduce sexually or asexually. Once a proglottid is fertilized it releases from the body. The proglottid is full of tiny zygotes. The proglottid then leaves the body through the feces. The larva bursts from the proglottid and infect an intermediary host. The larva grow in the intermediary host and are then transferred the primary host through consumption. Because the majority of the tapeworm’s life cycle is spent inside a host’s body, tapeworms do not have any defense mechanism against predators.




IV. Impact on the World and Humanity

Tapeworms are always found in third world countries where cleanliness and hygene are not as prevalent. Tapeworms can be found in multiple climates all around the world. However H. nana is most commonly found in dry and arid areas such as the Indian subcontinent, South America, and the Mediterranean. H. nana is also the most common tapeworm found in the United States. The symptoms are usually very vague and most of the time there are no symptoms at all. If symptoms do occur, they are usually weight loss and abdominal pain. If not treated tapeworm infections can be fatal. A tapeworm infection in a child is much more serious than one in an adult. The best way to eradicate H. nana in an area is to remove exposure of human fecal matter and any other kind of fecal matter for other tapeworms.



V. Journal Article Review

http://www.questiaschool.com/read/5005866733






This article is about a woman who discovered she had a tapeworm. She is originally from England but went to southern Africa for a trip. She spent nearly eight months there and had a blast. Unfortunately for her though she brought home a friend. The story is about how she found and cured herself of the tapeworm.




Video >>> http://www.youtube.com/watch?v=dy4cQON7-JU



Works Cited
"Cestodes." Innvista Home. Web. 14 Oct. 2010. .
"Chapter 4. The Cestodes (Tapeworms)." Public Health Information and Resources - Home Page. Web. 14 Oct. 2010. .
"Introduction: Cestodes (Tapeworms): Merck Manual Professional." Merck & Co., Inc. - We Believe the Most Important Condition Is the Human One. Web. 14 Oct. 2010. .
"Tapeworm Time!" Douchebaggery Abounds. Web. 14 Oct. 2010. .
"Tapeworm Time!" Douchebaggery Abounds. Web. 14 Oct. 2010. .
"Your Health: Hi Mum, I've Got an 8ft Worm in My Tum! Love Zoe Xxx; Zoe Young, 29, Will Never Forget Her Dream Holiday to Africa - Especially When Zoe Found out She'd Brought Home More Than Just a Lovely Suntan!" Questia Online Library. Web. 14 Oct. 2010. .

Hookworms

Hookworms

By Sienna Purse

I. Introduction

The hookworm is a parasitic nematode that lives inside the small intestine of mammals such as humans, dogs, and cats. The hookworm belongs to the phylum nematoda. There are two different species of hookworms, Ancylostoma duodenale and Necator Americanus. The species of Ancylostoma duodenale predominates in the Middle East, north Africa, India, and southern Europe, while Necator Americanus predominates in the Americas, Sub-Saharan Africa, southeast Asia, China, and Indonesia. The most significant risk of hookworm infection is anemia, secondary to loss of iron and protein in the gut. Hookworms suck blood and damage the mucosa. Hookworms are the leading cause of maternal and child morbidity in the developing countries of the tropics and the subtropics. Hookworms are thought to infect more than 600 million people worldwide.

II. Anatomy

Hookworms are long, skinny worms that are unsegmented. Hookworms come in different sizes from as long as one meter to as tiny as microscopic. Hookworms have three germ layers, the endoderm, exoderm, and mesoderm. Hookworms are psuedo-coelomates. Unlike flatworms, the digestive system of the hookworm has two openings. Ancylostoma Duodenale worms are grayish white or pinkish white with the head slightly bent in relation to the rest of the body. This forms a hook shape and is the reason for the naming of this worm. They possess well developed mouths with two pairs of teeth. The hookworm then excretes it's waste through the anus.

III. Form and Function

Hookworms thrive on the blood living animals. One can come in contact with hookworms by walking barefoot through contaminated soil. Also walking or running barefoot through an area that contains dog feces puts you at risk. When a hookworm finds a bare foot or an animal, they hook onto the passer with its sharp teeth-like plates and then burrow into the skin. They then burrow into the new host's bloodstream. After, they travel through the bloodstream to get into the lungs, then eventually the intestines. The worms then attach themselves into the walls of the intestines and start sucking the host's blood. Hookworms drink between 0.03- 0.2 mL of blood per day. Hookworms cause their host weakness and bad growth. Hookworms have no predators because they infect anything that eats them. In fact it is easier for them to be eaten because they don't have to go through the trouble of going through the bloodstream and instead go straight to the intestines. Hookworms are not hermaphroditic, therefore they have male and female worms and reproduce sexually. The male hookworm shoots sperm into the reproductive tract of the female. Female hookworms produce about 10,000- 20,000 eggs per day. These eggs are passed out of the body through the host's feces. the eggs take about 48 hours to incubate in the soil until they hatch into immature larvae. These larvae take about 6 weeks to develop into mature hookworms. Once they are fully developed the cycle starts all over again.

IV. Impact on the World/Humanity

It has been suspected that approximately 600 million to 1 billion people are affected by hookworms. Hookworms arise from a combination of intestinal inflammation and progressive iron/protein-deficiency anemia. Larval invasion of the skin might lead to intense, local itching, usually on the foot or lower leg, which can be followed by lesions that look like insect bites and can blister. These lesions can last for a week or more. Coughing, chest pain, wheezing, and fever will sometimes occur. Epigastric pains, indigestion, nausea, vomiting, constipation, and diarrhea occur later. Signs of advanced severe infection are those of anemia and protein deficiency, including emaciation, cardiac failure, and abdominal distension with ascites.

V. Journal Article Review

Link-------http://www.guardian.co.uk/lifeandstyle/2010/may/23/parasitic-hookworm-jasper-lawrence-tim-adams

This article was not about hookworms in general. This is a story of how Jasper Lawrence infected himself with 50 hookworms to rid himself of asthma. Lawrence's asthma had gotten so bad to where he could no longer play with his kids or walk up one flight of stairs without being winded. His aunt then told him about a BBC radio documentary she heard about the parasitic hookworms treating allergies. He researched this topic non-stop until he finally decided he would go to Africa to be infected. He went to Cameroon's local villages and proceeded to walk around without shoes. He then came home and saw that he had no changes or symptoms until one day in early spring he rolled down his car window and had no reactions like he would have normally had. Lawrence then decided that he would help others with terrible conditions such as Crohn's, hay fever, or multiple sclerosis. He ended up starting a business through these by harvesting his own hookworms out of his feces and then repeatedly cleaning them and then at last packaging them in small containers. The FDA started to investigate him so him and his business partner up and left and have been traveling around the world hiding from the FDA.

Bibliography!

Hookworm- Wikipedia, the Free Encyclopedia. (n.d.) Wikipedia, the free encylopedia. Retrieved October 14, 2010, from http://en.wikipedia.org/wiki/Hookworm

Hookworm- Creation Wiki, the Encyclopedia of Creation Science. (n.d.) Creation Wiki, the Encyclopedia of Creation Science. Retrieved October 14, 2010, from http://creationwiki.org/hookworm

Hookworm Disease- The Free Dictionary. (n.d.) The Free Dictionary. Retrieved October 14, 2010, from, http://medical-dictionary.thefreedictionary.com/hookworm+disease

Hookworm Infection- Parasitic Disease Information. (n.d.) CDC. Retrieved October 14, 2010, from http://www.cdc.gov/ncidod/dpd/parasites/hookworm/factsht_hookworm.htm

Pictures From...

(Figure 1) http://amazinghumanbody-prakash.blogspot.com/2009/09/diseases-of-digestive-system.html

(Figure 2) http://profiles.nlm.nih.gov/VV/B/B/F/K/_/vvbbfk.jpg

(Figure 3) http://creationwiki.org/Hookworm

The Lancet Liver Fluke (Dicrocoelium dendriticum)

I. Introduction
• The Lancet Liver Fluke (Dicrocoelium dendriticum)
• Phylogenetic placement- Platyhelminthes
• Habitat- The adult life of the Lancet Liver Fluke is lived in the bile duct of grazing mammals such as sheep or cows, but it grows to maturity inside of the Terrestrial Snail and ant as it attempts to find a suitable host.

II. Anatomy



III. Form & Function

The Lancet Liver fluke lives the majority of its life in the bile duct of grazing mammals, such as sheep or cows, where it feeds on liver tissue through an oral sucker on the anterior of its body. The fluke has no separate system to eliminate waste, so any waste is also expelled through this oral sucker. The life of the Lancet liver fluke begins when sexually mature flukes reproduce in the liver. The newly laid fluke eggs are expelled in the feces of the grazing mammal, where they wait until they are consumed with the feces by the Terrestrial Snail (Cochlicopa lubrica). Once inside the snail, they flukes hatch and grow to their juvenile stage. Upon reaching this stage, the flukes begin to drill through the wall of the gut towards the digestive tract. This action reaches the attention of the snail, who attempts to defend itself by encasing the flukes in cysts and expel them in its mucus. Once the flukes are expelled by the snail, they lie in wait of an ant, who extracts moisture from the mucus trail of the terrestrial snail. Once an ant consumes this moisture, and brings it back to the colony for other ants, the flukes drill out of the ant’s stomach and into the brain, where they begin to control the ant. The controlled ant acts normal during day to day function in the colony, but from dusk until dawn the ants sit at the tops of blades of grass instead of moving back to the colony with the other ants. This is all an effort to be eaten by a grazing mammal, who often feed at these hours. Once a grazing mammal eats the grass the ant was sitting upon, the flukes end up inside the mammal’s intestine. The flukes then move from the intestine to the bile duct of the liver, where they feed upon liver tissue and reproduce. The eggs laid by the flukes are expelled in the feces of the mammal, and the cycle begins once again.

IV. Impact on World/Humanity

• Cases of human infestation by the lancet liver fluke are very rare and can be treated with Praziquantel at 25 milligrams per kilogram three times a day for one day.
• The flukes can cause liver failure if enough flukes infest the bile duct of a mammal, such as a sheep or cow, often causing economic loss among farmers.

V. Journal Article Review

Link to article---> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1701347/pdf/brmedj02303-0034.pdf

The Journal Article found was not on the Lancet Liver Fluke, but on the fascoiasis
Hepatica liver fluke. The flukes are similar in the symptoms and damage caused by infection, so such an article is still pertinent. The Article in question details the infection of many adults and children who ate wild watercress from a bed near infected sheep and cattle. Soon after the consumption of the parasites, those infected began to feel symptoms of malaise, intermittent fever, night sweats, weight loss, some pain in the right coastal margin, and severe coughing in some. The adult patients were treated with intramuscular injections of emetine hydrochloride, and the children with oral doses of Chloroquine. After three weeks, all patients were discharged.

Video:

http://www.youtube.com/watch?v=ZgAEeisfHW8

Bibliography:
• Dicrocoelium dendriticum - Wikipedia, the free encyclopedia. (n.d.). Wikipedia, the free encyclopedia. Retrieved October 13, 2010, from http://en.wikipedia.org/wiki/Dicrocoelium_dendriticuHardman,

• E. W., Jones, R. L., & Davies, A. H. (1970). Fascioliasis-A Large Outbreak. Fascioliasis-A Large Outbreak, 1, 4. Retrieved October 13, 2010, from the PubMed Central database.

• Merck Veterinary Manual. (n.d.). The Merck Veterinary Manual. Retrieved October 13, 2010, from http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/22705.htm
• Panini. (n.d.). A Fluke of Nature. Panini's Home Page. Retrieved October 13, 2010, from http://hilbertspaces.com/articles/fluke/fluke.html

• Parasitic Mind Control [Documentary]: National Geographic.

-Dylan Burchett

Water Bear-- Labeled Diagram -- Zachary Kaye

(forgot to include this is my real post...)

Labeled diagram of Water Bear:

Water Bear (Tardigrada) -- Zachary Kaye

Introduction: The water bear is classified under the phylum of Tardigrada. They were discovered by an amateur microscopist in 1773, and for a while, scientist had trouble trying to fit it into their classification system. The fact that they were given their own phylum, suggests that they are not closely related to any other animal. There are over 100 species of water bears, and they are all very similar and hard to tell apart. Water bear’s can be found virtually anywhere on earth, from the top of the Himalayas, to the hottest deserts. The water bear can be found right in your backyard, and is the only living animal that is able to survive the vacuum of space. (Challis)

Anatomy: The water bear is composed of a head, body, and a tail-like structure. It has eight legs, each with claws at the end of them. The water bears mouth contains sharp pointy objects called stylets, which they use to bite into moss and algae.

Form and Function: Water bears feed primarily on the fluids from animals and plant cells, such as moss. They do this by either sucking on the plant, or eating it. Water bears also eat microscopic animals such as nematodes or rotifers, and excrete the waste out of their rectum. If conditions become bad enough for the Water bear to the point where it could die, it goes into a state of suspended animation, otherwise known as an “antibiotic state”. It can stay in this state until conditions improve. The water bear has no predators, making its survival rate increase even more. The water bear is very interesting when it comes to reproduction. There are a couple of ways it can perform this task. The first is that the male can place his sperm into sperm-storing organs in the female. The second is that the female can insert a special structure into the male and grab the sperm from the male’s body. A few species are parthenogenic and capable of producing young without mating. In some species, individuals have reproductive organs of both males and females. However, most water bears are thought to lay eggs. (FCPS EDU) (Cook)

Impact on the World/Humanity: Water Bears do not seem to really help or hurt people. They spend all their time in mosses, lichens, and water. They do help with eating and breaking down these plants. (FCPS EDU)

Journal Article Review: The main point from the review is that the water bear is not very widespread in terms of people’s knowledge of them. If you were to ask people if they have ever heard of an animal with the characteristics of a water bear, chances are they would say no. However, the water bear is one of the most fascinating and most unknown animals in the world. The review says that one of the main reasons for the lack of knowledge on water bears is their size. This makes it hard to learn about them in detail, especially since they walk on their legs, and when viewing them from a microscope, you are looking at their back. I think that the author is trying to say that if more people were to learn about the water bear, it could become an animal that we could learn about in great depth. (Mach, 2000)

http://www.youtube.com/watch?v=W9WWysGBAlU&feature=player_embedded

Bibliography:

Challis, S. (n.d.). Tardigrades. Retrieved from http://stevechallis.net/Tardigrades.php

FCPS EDU, Initials. (n.d.). Water bear. Retrieved from http://www.fcps.edu/islandcreekes/ecology/water_bear.html

Cook, J. (n.d.). Water bears: tardigrada - behaivor and reproduction. Retrieved from http://animals.jrank.org/pages/1728/Water-Bears-Tardigrada-BEHAVIOR-REPRODUCTION.html

Journal Article Review: Mach, M. (2000, June). The incredible water bear. Retrieved from http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artjun00/mmbearp.html