Causes, Risk Factors, and Prevention |
Modes of Transmission and Prevention
Toxoplasmosis has three main modes of transmission: Food-borne, animal-to-human (zoonotic), and Mother-to-child (congenital) [1] . Prevention is centered around these three main modes of transmission. Other rare cases [1] of transmission also exist.
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Food-borne
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Zoonotic
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Congenital
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Rare Cases
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Food-Borne Transmission
The tissue form of the parasite (bradyzoites) can be transmitted to humans by food when people eat these microscopic cysts. This can occur when eating undercooked meat that is contaminated. This risk is especially high in pork, lamb, and venison [1].
This Food-born transmission can also occur when eating food that was contaminated by shared utensils such as knives, cutting boards and counter tops that have had contact with raw, contaminated meat.
This Food-born transmission can also occur when eating food that was contaminated by shared utensils such as knives, cutting boards and counter tops that have had contact with raw, contaminated meat.
Prevention:
To reduce the risk of meat born transmission, cook all meats to recommended temperatures: [7]
• 145 with a 3 minute rest time, for cuts of meats (other than poultry)
• 160°F with no rest time required, for ground meats (other than poultry)
• 165°F for all poultry ground or cuts.
• 145 with a 3 minute rest time, for cuts of meats (other than poultry)
• 160°F with no rest time required, for ground meats (other than poultry)
• 165°F for all poultry ground or cuts.
Pork's new recommended cooking temperature of 145°F with a 3 minute rest time gives a great juicy flavor safely [7].
(Pictures via google images)
(Pictures via google images)
Animal -to-Human |
“We have dad clean the litter box, because it is when the particles in the cat litter get kicked up into the air during cleaning that you can breathe them in or get the spores on your hands and accidentally ingest them.” Kim Windels CNM Boulder Women's care (CDC Photo) |
Mother to Child (Congenital) Transmission
A woman who has her first infection with Toxoplasma during pregnancy can pass the infection to her unborn child. The woman may not be symptomatic, but there can be severe consequences for the unborn child, such as diseases of the nervous system and eyes.
Congenital Toxoplasmosis Triad: Severe congenital Toxoplasmosis in infected infants often results in a triad of three main clinical presentations, all involving the CNS, these include [9]:
Other Clinical Manifestations: [10]
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“There is not much we can do about [Toxoplasmosis infection] once a mom gets it. So it is all about prevention!” Kim Windels CNM Boulder Women's care (during a person to person interview on 4-22-17) |
Figure 16 Hydrocephalus, or the over accumulation of cerebrospinal fluid within the brain, can result from congenital toxoplasmosis infections. Build-up of fluid in the brain cavity leads to increased intracranial pressure; pressure on the brain causes a variety of developmental/mental problems throughout the lifetime of an affected child. [11]
Prevention:
Once mom is infected some medications have shown effectiveness at preventing transmission to the baby. Spiramycin, an antibiotic, collects in the placental tissue to help prevent the parasites travel to the fetus. In the cases of fetal infection, this medication has been shown to reduce the severe health outcomes [6].
Figure 17 Spriamycin is an antibiotic used to help prevent congenital transmission. [6]
(Picture via Google images)
(Picture via Google images)
Rare Instances of Transmission
- Organ transplant can cause transmission if the donor had Toxoplasma and some parasites were in the tissue that was transplanted.
- Uncommonly, direct blood transmission is possible [1]. This can occur:
- When receiving infected blood via transfusion.
- In laboratory workers who handle infected blood that acquire needle sticks.
Prevention |
- Proper handling of lab specimens and hand hygiene
- Testing to insure donated tissues are safe.