Atlas of foodborne infections
transmitted by contaminated food and water

Atlas of Patogens Contents Information sources Glossary Administration

Toxoplasma gondii

CZ: toxoplazma
EN: toxoplasma

Occurrence:
Meat and Meat Products
Fruits and Vegetables
Water and Beverages
Delicatessen


Category:
Parasites


Foodborne Disease:
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toxoplasmosis - "flu-like" symptoms such as swollen lymph glands, muscle aches and pains; severe cases can damage eyes or brain


Description:
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The only known definitive hosts for Toxoplasma gondii are members of family Felidae (domestic cats and their relatives).  Unsporulated oocysts are shed in the cat’s feces .  Although oocysts are usually only shed for 1-2 weeks, large numbers may be shed. 

Oocysts take 1-5 days to sporulate in the environment and become infective.  Intermediate hosts in nature (including birds and rodents) become infected after ingesting soil, water or plant material contaminated with oocysts .  Oocysts transform into tachyzoites shortly after ingestion.  These tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites . 

Cats become infected after consuming intermediate hosts harboring tissue cysts.  Cats may also become infected directly by ingestion of sporulated oocysts.  Animals bred for human consumption and wild game may also become infected with tissue cysts after ingestion of sporulated oocysts in the environment . 

Humans can become infected by any of several routes:

In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host. 

Diagnosis is usually achieved by serology, although tissue cysts may be observed in stained biopsy specimens .  Diagnosis of congenital infections can be achieved by detecting T. gondii DNA in amniotic fluid using molecular methods such as PCR .


Pictures:

Toxoplasma gondii
Source: Final host of T. gondii - cats, Felidae
Toxoplasma gondii
Source: Fresh meat from infected animals - source of infection
Toxoplasma gondii
Source: Life cycle of T. gondii
Toxoplasma gondii
Source: Oocysts of T. gondii in feces (flotation technique)
Toxoplasma gondii
Source: Pseudocyst of T. gondii in brain of intermediate hosts
Toxoplasma gondii
Source: Pseudocysts of T. gondii in brain of intermediate hosts

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