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Learning objectives

  • Explain why we include the study of parasitic worms within the discipline of microbiology
  • Compare the basic morphology of the major groups of parasitic helminthes
  • Describe the characteristics of parasitic nematodes, and give an example of infective eggs and infective larvae
  • Describe the characteristics of parasitic trematodes and cestodes, and give examples of each
  • Identify examples of the primary causes of infections due to nematodes, trematodes, and cestodes
  • Classify parasitic worms according to major groups

Parasitic helminths are animals that are often included within the study of microbiology because many species of these worms are identified by their microscopic eggs and larvae. There are two major groups of parasitic helminths : the roundworms (Nematoda) and flatworms (Platyhelminthes). Of the many species that exist in these groups, about half are parasitic and some are important human pathogens. As animals, they are multicellular and have organ systems. However, the parasitic species often have limited digestive tracts, nervous systems, and locomotor abilities. Parasitic forms may have complex reproductive cycles with several different life stages and more than one type of host. Some are monoecious , having both male and female reproductive organs in a single individual, while others are dioecious , each having either male or female reproductive organs.

Nematoda (roundworms)

Phylum Nematoda (the roundworms ) is a diverse group containing more than 15,000 species, of which several are important human parasites ( [link] ). These unsegmented worms have a full digestive system even when parasitic. Some are common intestinal parasites, and their eggs can sometimes be identified in feces or around the anus of infected individuals. Ascaris lumbricoides is the largest nematode intestinal parasite found in humans; females may reach lengths greater than 1 meter. A. lumbricoides is also very widespread, even in developed nations, although it is now a relatively uncommon problem in the United States. It may cause symptoms ranging from relatively mild (such as a cough and mild abdominal pain) to severe (such as intestinal blockage and impaired growth).

A micrograph of a tapered oval cell of approximately 30 mm in length.
A micrograph of the nematode Enterobius vermicularis , also known as the pinworm. (credit: modification of work by Centers for Disease Control and Prevention)

Of all nematode infections in the United States, pinworm (caused by Enterobius vermicularis ) is the most common. Pinworm causes sleeplessness and itching around the anus, where the female worms lay their eggs during the night. Toxocara canis and T. cati are nematodes found in dogs and cats, respectively, that can be transmitted to humans, causing toxocariasis . Antibodies to these parasites have been found in approximately 13.9% of the U.S. population, suggesting that exposure is common. Won K, Kruszon-Moran D, Schantz P, Jones J. “National seroprevalence and risk factors for zoonotic Toxocara spp. infection.” In: Abstracts of the 56th American Society of Tropical Medicine and Hygiene; Philadelphia, Pennsylvania; 2007 Nov 4-8. Infection can cause larval migrans, which can result in vision loss and eye inflammation, or fever, fatigue, coughing, and abdominal pain, depending on whether the organism infects the eye or the viscera. Another common nematode infection is hookworm , which is caused by Necator americanus (the New World or North American hookworm) and Ancylostoma duodenale (the Old World hookworm). Symptoms of hookworm infection can include abdominal pain, diarrhea, loss of appetite, weight loss, fatigue, and anemia.

Questions & Answers

I mportance of microorganisms
azarsh Reply
microbiology is the study of micro organisms those been unicellular multicellular or acelluar
Nwakaego Reply
what is microbiology
Ebuka Reply
why study microbiology
David Reply
to know the cause of certain disease and how to cure them
Racheal
without micro, medicines in term of diagnostic and cure would be far away from realizing its objectives
Louisiaste
It's help to give the best medication.
Olayinka
Unvin Prisca the immune system
Gyabaa Reply
immune system is a complex of organ tissues and specialized cells which identify or kill the pathogens.
Mohammad
Thanks
shamim
explain to me the pathogenesis of plasmodium
Angelo
what is difference between bacillus and ecoil
Rymes Reply
similarities between prokaryotic cell and eukaryotic cell
Ednah Reply
Eukaryotic cells contain membrane-bound organelles, including a nucleus. ... Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle. Prokaryotes include two groups: bacteria and another group called archaea.
Priya
thanks
Sarpong
what is different between plasma and serum?
Alif
difference between plasma and serum is that plasma is liquid n serum is fluid
Priya
what is microbiology
Eliham
what is the diseases caused by the microorganisms
Emmanuel
both cells have plasma membrane, which services as a barrier between the inside of the cell and outside. both prokaryotes and eukaryotes have ribosomes. they receive messages from messanger RNA molecules, telling them what proteins the cell needs.
Abdinur
Thanks
Dominic
Some bacteria infection
Dominic
what is the name given to infection got from the hospital
Mukisa
Nosocomial infection
Gifty
what is the apportion
Riyaaq
what is the main functions of organelles
Ishaq
what is main function of right and left side of the brain.
Theophile
Salifu. microbiology is the study of oganisms that are too small for the naked eyes to see. this include bacteria
Theophile
Cabdi. apportion is to divide or share out
Theophile
yap
bako
what is the parasitic helminths?
bako
what are pathogens
Oluka Reply
any disease causing microorganism that can invade the body and cause harm
famuyiwa
hepatitis b
Oluka
what's da answer
Oluka
any diseases that course harmful to body
Musa
hepatitis is usually implementery of the liver and is commonly course by virus infection
Musa
a type of virus that causes severe illness lasting from two to six weeks it may cause massive lived necrosis and cirrhosis
famuyiwa
hepatitis B are transmitted when in contact with body fluid such as blood,semen,varginal secration that contain the hepatitis b virus
Musa
I understand necrosis,means death of all cell or injury of blood supply, but what is cirrhosis pls
Musa
sorry meant liver cirrhosis
famuyiwa
good evening all
Billy
ok liver damage
Musa
I have a question
Billy
Hey welcome all of you...i think you are discussing about Micro-organisms..what does it Micro?
Gazu
how about, scabies (bacteria) yeah can some one gist me abt it
Billy
sorry what doest it mean Micro organism?
Gazu
microorganism are minute living organisms found almost everywhere. they can be autotrophic heterotrophic or chemotrophic
famuyiwa
Tell me about enzyme kinetics
Jaypal
wowoww thanks a lot farmuyiwa Alice
Gazu
have anyone colony pigmentation of different types of bacteria such as Aeromonas, Edwardsiella, vibros,
Sadiqur
yes dear sadiqur Bacterias are live in everywhere.. .
Gazu
microorganisms are arganism that cannot been seen with 👀 until by the use of microscope
Musa
microorganisms are arganism that cannot been seen with 👀 until by the use of microscope
Musa
yhea organisms are organisms they are naked eye/can't seen by our eyes
Gazu
and scabies are one of the most common skin condition that can course itches and raches.
Musa
and also scabies are not infection, but an infestation
Musa
my Q is what is the contribution of van-leeuwenhoek in field of microbiology
Musa
Antony van leevenhoek is father of microbiology.
Jaypal
Anton Van leewun hook is discovered Microscope it's true or not? who can brief me please
Gazu
micro organisms are organism that cannot be seen with an aided eyes ,but by the use of microscope
Ssmuel
Yes.. He discover first microscope. He take 2 lence at a time and he saw the plant cells... Thus he was called father of microbiology
Jaypal
who examined water from a bathtub and discovered microbes
famuyiwa
for instance any type of Stagnant water is creat there are d/t tupes of small animals.. so those animals are called Micro organism?
Gazu
thank you javpal for Describing.
Gazu
Hi the father of microbiology is Louis Pasteur
bako
Then the father of medical microbiology is Robert Koch
bako
can you please differentiate between vacuoles and inclusion bodies
Noor Reply
vacuoles consists of watery solution called cell sap while bodies are organelles
Prince
5 difference please
Noor
Archaea is an odd type of bacteria that live in extreme environments; high salt, high temperature etc. usually called extremophiles.
Danesia Reply
you know anyone that has delt with enterobacter agglomerans.
Vernon
it is a type of gram negative bacteria and its ubiquitous mostly isolated from plant stuffs and also from faecal material of animals. I heard the name pantoea . it is bacillus in structure.
Sujan
OLUKA MARTIN
Oluka
What are the classification of microorganisms
Portia Reply
Basic classification are eukaryotic and prokaryotic..
micro organisms are classified into three namely: Archaea, eukaryote and prokaryotic organisms
Blandine
Yay that's right
what is archaea
Ateeq
I've got an issue with the message view
Frank Reply
Is there any effective way to learn microbiology.
Frank Reply
I have some basic knowledge of biology. I mean i'm totally beginner in that field.
Frank
Assuming that i'm interested in neuroscience. What is the best way to master that particular subject.
Frank
Hi
Can you wait me just a minute
Iam apologies for guidance you in neuroscience.. I'm not physician.. I'm microbiologist
My pleasure to join to you
Let's begin a conversation
Frank Reply
What would be saying
?
Akram
do you know anything about microbiology
diana
I have so much studying to catch up on🙄
Britnee
any study tips
Britnee
Yas of course
What would you like to know
well i'm studying Pharmacy second year and i just started With Microbiology
diana
if you have any basics to tell us 🤷🏻‍♀️ would be helpful
diana
Yas, first you must know that you will have a very easy lecture..
In second stage you will try to learn the type of microbiology
A simple definition for microbiology
In second stage you will try to learn the type of microbiology.. you must learn the bacteria..its structure.. Classification of bacteria according to shape..
It's so easy

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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