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Life cycle of Toxoplasma gondii. 1 - Insporulated oocysts are shed in the cat’s feces. 2 – Intermediate host in nature (including birds and rodents) become infected after ingesting soil, water or plant material contaminated with oocysts. 3 – Oocysts transform into tachyzoites shortly after ingestion. These tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites. 4 - Cats eat infected animals (such as rodents or birsds) and shed unsporulated oocysts. 5 – Intermediate hosts (such as pigs and cows) ingeset oocysts from contaminated water, soil, or plant material. 6 – Humans can become infected when they eat undercooked meat of infected animals harboring tissue cysts. 7 – Humans can also become infected when they consume food or water contaminate with cat feces or by handling fecal-contaminated soil or cat’s litter box. 8 – Humans can also become infected via the placenta from fetus to mother. 10 – Tissue cysts can form in skeletal muscle, myocardium, brain, and eyes. 11 – Diagnosis of congenital infection can be achieved by detecting T. gondii DNA in amniotic fluid using molecular methods such as PCR.
The infectious cycle of Toxoplasma gondii . (credit: “diagram”: modification of work by Centers for Disease Control and Prevention; credit “cat”: modification of work by “KaCey97078”/Flickr)
A) A micrograph of curved cells with a nucleus. B) micrograph of a sphere with many smaller spheres inside.
(a) Giemsa-stained Toxoplasma gondii tachyzoites from a smear of peritoneal fluid obtained from a mouse inoculated with T. gondii . Tachyzoites are typically crescent shaped with a prominent, centrally placed nucleus. (b) Microscopic cyst containing T. gondii from mouse brain tissue. Thousands of resting parasites (stained red) are contained in a thin parasite cyst wall. (credit a: modification of work by Centers for Disease Control and Prevention; credit b: modification of work by USDA)
  • How does T. gondii infect humans?

Babesiosis

Babesiosis is a rare zoonotic infectious disease caused by Babesia spp . These parasitic protozoans infect various wild and domestic animals and can be transmitted to humans by black-legged Ixodes ticks. In humans, Babesia infect red blood cells and replicate inside the cell until it ruptures. The Babesia released from the ruptured red blood cell continue the growth cycle by invading other red blood cells. Patients may be asymptomatic, but those who do have symptoms often initially experience malaise, fatigue, chills, fever, headache, myalgia, and arthralgia. In rare cases, particularly in asplenic (absence of the spleen) patients, the elderly, and patients with AIDS , babesiosis may resemble falciparum malaria, with high fever, hemolytic anemia, hemoglobinuria (hemoglobin or blood in urine), jaundice, and renal failure, and the infection can be fatal. Previously acquired asymptomatic Babesia infection may become symptomatic if a splenectomy is performed.

Diagnosis is based mainly on the microscopic observation of parasites in blood smears ( [link] ). Serologic and antibody detection by IFA can also be performed and PCR-based tests are available. Many people do not require clinical intervention for Babesia infections, however, serious infections can be cleared with a combination of atovaquone and azithromycin or a combination of clindamycin and quinine .

Micrograph of red blood cells with dark circles inside.
In this blood smear from a patient with babesiosis, Babesia parasites can be observed in the red blood cells. (credit: modification of work by Centers for Disease Control and Prevention)

Chagas disease

Also called American trypanosomiasis , Chagas disease is a zoonosis classified as a neglected tropical disease (NTD). It is caused by the flagellated protozoan Trypanosoma cruzi and is most commonly transmitted to animals and people through the feces of triatomine bugs. The triatomine bug is nicknamed the kissing bug because it frequently bites humans on the face or around the eyes; the insect often defecates near the bite and the infected fecal matter may be rubbed into the bite wound by the bitten individual ( [link] ). The bite itself is painless and, initially, many people show no signs of the disease. Alternative modes of transmission include contaminated blood transfusions, organ transplants from infected donors, and congenital transmission from mother to fetus.

Questions & Answers

what is the difference between prokaryotic and eukaryotic?
Brian Reply
how many types of cell
Brian Reply
Two PLANT AND ANIMAL CELL
Shafi
actually we have two major types eukaryotic and prokaryotic eukaryotic may me unicellular as yeast or multicellular as plant ,animal, algae,fungi prokaryotic as bacteria
Khaled
hi, what are the most important things i should focus on to passed this class
Mulbah
guys I know is out of topic but I really need help
Mulbah
Hi
Brian
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Mulbah
you only need to focus on your study and you should expand your time of studying if there is any blockage for you
Alieu
Hi dear any one can splain how it is made Collagen peptide
natural
It's made of many bonds and proteins that are used to block
Lee
what is the evolutionary Trent of butterfly
ANTHONY
the history of cell theory.
Usman Reply
what are the principle of gram staining?
Hussaina
gram positive bacteria have matrix 10% and murein 90% which consists of peptidoglycan about four layers (very thick). gram negative bacteria have matrix 90% and murein 10% which consists of peptidoglycan about 2 layers (thin)
Khaled
so in gram positive bacteria : purple stain is trapped make alcohol can't leach it in gram procedure so appear purple (violet) in gram negative bacteria : purple stain is leached by alcohol and red stain of safranin after leaching give red colour appearance to gram negative.
Khaled
Name 4 Afb positive and negative bacteria?
sujay Reply
e coli staphylococcus streptococcus pseudomomas
Matilda
what invention
MALAMI Reply
?
Teressa
learn about micro bacterium tuberculosis
Dian
What are the conventional methods of microorganism detection?
Anna Reply
What are the convectional methods for microorganism detection
Anna
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dennis Reply
Are problèms related for crystal.
Abdullahi
is a calculus formed in the kidney
stephen
yes
tanya
eat light foods
Chandrima
just go tjorough bland diet
Chandrima
what are monomers, and is there a section for bacterial metabolism
SAM Reply
who is Aristotle?
soko Reply
Aristotle is the father of Biology.
Margrete
is a father of western philosophy
Kamaluddeen
father of classification of organisms
Williams
This is one of the greatest of the ancient Athenian philosophers
stephen
Sorry Aristotle was father of zoology
Sauri
father of classification of organisms
Williams
father of classification
Joy
Okay father of zoology
Joy
The bacteria that cause plague belong to the genes
Javid Reply
structure and functions of bacterial cell economic environment
Pavi Reply
what is haemaophilus influenzae
GALI Reply
what is the different between eubacteria and archaer bacteria
GALI
what the important of dna
Yunusa Reply
it act as hereditary material, coding for proteins and guide for life processes such as development reproduction etc
khan
Saving information from one generation to another, plus Structurale, fonctional, reproductive role
Ben
It's just structural, functional&
Nandkishor
liver is the largest organ of the body
maryam Reply
Liver is the largest internal organ within the human body but for this question the skin is the largest organ of the human body.
Margrete
Liver is the largest internal organ within the human body but for this question the skin is the largest organ of the human body.
Margrete
differences between prokaryotes and eukaryotes
Taiwo Reply
Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not.
Margo
hello
usman
margo calvi....its your simple difference
Sadiqur
likely objective questions
Naa
what is largest Organ in the body
Dr
Skin is the largest organ in the body
Yadav
heart is the largest organ of the body
usman
liver is the largest organ in the body
maryam
liver is the largest organ in the body
maryam
skin
Janet
skin
Elyas
bilharzia
Elyas
i need formation
Elyas
liver is the largest organ in the body
maryam
Skin is the largest
Amin
skin
Amin

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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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