Prevention of Human Toxoplasmosis

I describe the transmission of the toxoplasmosis gondii, a parasitic protozoan, through its life cycle, and where relevant how the transmission process can be broken to help prevent

infection in people.

Prepared by Michael

at Pictures-of-cats.org

Please read each section carefully. Thanks.

The mouse is infected:

• through mother's placenta when an embryo due to mother's chronic infection
• or through fecal contamination, which can be facilitated by the fly and cockroach as transport hosts

The mouse is an intermediate host.

Oocyst is a hardy, thick-walled spore able to survive for lengthy periods outside a host. The toxoplasmosis organism develops within the spore.

A cat, a primary host, eats a mouse that is infected with toxoplasmosis. Rarely cats also ingest oocysts in contaminated soil. An infected mother can infect unborn kitten.

The main way a cat becomes infected is by eating raw meat and wild animals (mice usually). Most cats have no symptoms.

Gardener

by ktylerconk

http://www.flickr.com/photos/ktylerconk/506330298/sizes/l/

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garden gloves

by Huron Tours & Travel

http://www.flickr.com/photos/huronvalleytravel/4689204320/sizes/m/

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hospital gloves

by striatic

http://www.flickr.com/photos/striatic/884427/sizes/o/

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by Southern Foodways Alliance

http://www.flickr.com/photos/southernfoodwaysalliance/4309432874/sizes/o/

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Child in sand

by Tammra McCauley

http://www.flickr.com/photos/tammra/280990811/sizes/o/

Credits for photographs - usernames and URLs provided. I can't provide a link on Prezi.

Cat defecating

by jlizard043

http://www.flickr.com/photos/joshnsara/2402135334/sizes/z/

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cat mouse

by Nina Matthews Photography

http://www.flickr.com/photos/21560098@N06/6633398747/sizes/m/

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fly

by adamentmeat

http://www.flickr.com/photos/adamentmeat/4920981387/sizes/z/

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litter tray

by goodiesfirst

http://www.flickr.com/photos/scaredykat/4589207085/sizes/z/

Important: By far the majority of human cases of toxoplasmosis come from eating raw and undercooked meat: pork and lamb are the most common. Also oocysts can stick to fresh vegetables when taken from the soil. There is an overemphasis on the domestic cat and an underemphasis on food handling procedures at home.

Prevention

A cat can be tested to check if she has been exposed. A positive test for a healthy cat indicates she has acquired immunity and is "not a source of human contamination". This is not a 100% certainty, however. See your vet.

Prevention

Feed cat only wet or dry commercial cat food or cooked meat and prevent cat foraging (roaming and hunting).

Fresh meat should be cooked at a minimum temperature of 150 F (65.5 C). Hands should be washed with soap and water after handling raw meat. Surfaces should be cleaned properly. Freezing does not necessarily kill all organisms.

A infected cat defecates outside the home or in a litter tray. Oocysts are shed in the feces. If the feces are outside the home people who do gardening or people in the garden can pick up and ingest the spores released from the oocysts. Prey of the cat can also do this.

Important:

• A cat with an active infection can only pass it on for 7-10 days in her entire life, when there is an acute infection.
• It takes 1-3 days for oocysts that have been shed in feces to become infectious. This means the litter tray would have to be uncleaned for 1-3 days before the infection could be passed on.

Cats, domestic and some wild, are the only animals who pass on the infectious stage of this parasite through their feces.

Child in sand box. A potential source of infection.

Gardener picks up feces on hands and then transfers spores from oocysts to raw food or to an opening on their body.

Prevention

A gardener should wear work gloves when working in soil that might be contaminated with cat feces. Children's sand piles should be covered when unused. Wash hands before meals and before touching face.

Note: Stray cats are very important in the causes of toxoplasmosis. They are the most important factor in the spread of toxoplasmosis to humans and other animals. Some form of legislation is required, perhaps. Some species of wild cat also shed oocysts. Nonfelines don't.

Prevention

Remove stools daily from litter tray. This removes oocysts before they "sporate".

Clean litter with boiling water and diluted bleach solution.

Cover children's sandboxes when not used to prevent stray cats using it as a litter box.

Pregnant woman should wear disposable gloves when handling cat litter. Don't get rid of the cat but dispose of the litter carefully! But note: pregnant women should be tested to see if they have acquired immunity. In the USA less than 33% of women of child bearing age have antibodies (immune). In France 84% of women of child brearing age are immune.

Sources: Breaking the transmission chain of Toxoplasma: a program for the prevention of human toxoplasmosis - by J K Frenkel AND Cat Owner's Home Veterinary Handbook.