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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

Hi everyone, is these site only about microbiology? I want a site which I can download articles on hematological and biochemical profile
Peter Reply
I am about to enter school and am going for MCB
Olugbenga Reply
What is DNA damage and repair
Sree Reply
removal of nucleotide bases from DNA is damage n addition or insertion of bases in DNA is repair.
Rashmi
replication is a term related to generation of new DNA from a parental DNA.
Rashmi
role of microorganism as pathogens
Parteek Reply
to live inside the host body, reproduction n destroy the immune system of host body.
Rashmi
what is replication
rajesh
please give me ans
rajesh
replication is a term related to generation of new DNA from parental DNA.
Rashmi
difference between endotoxin and exotoxin
Binkheir Reply
toxins released inside the cell or a body is endotoxin n toxins released outside the cell or a body is exotoxin.
Rashmi
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there are many we classify it according to their shapes gram negative or gram positive
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MSc entrance prepare books and questions LA etha base pani irukum..
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certain cancer or pneumonia 🤔
Kushal
penicillium crysogenum
Kushal Reply
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Tasiu
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Hw u
Tasiu
HRU frinds
Arhaan
any good reference for oncology?!!!!
Pankaj Reply
K.D tripathi
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what is the microbiology
Fadumo Reply
it is the study of microorganisms
Sneha
microorganis means
Ghuge
the organism can not be seen by eyes they can be seen with the help of microscope
rajesh
microbiology is the study of microorganism and microorganism are such as bacteria ,parasite, viruses and fungi and etc.. those are cant be seen with asked eyes and can be seen with help of microscope . I hope this helps you
Tharra
what is virology
Bismarck Reply
the study of viruses
Adan
what is myrology
Bismarck
myrology or mycology?
Adan
mycology
Bismarck
the study of fungi.
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Mycology study fungi
Hakeeb
study of viruses
Rashmi
what are the major topics that you cover under micro biology
Bismarck Reply
virology,mycology,bacteriology
Adan
identification n application of microorganisms
Rashmi
How do u apply micro biology in medicine
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in preventing, diagnosis and treatment of infectious diseases.
Adan
and also in carrying out test And Analysis
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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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