Currently, there is no vaccine to protect against Toxoplasmosis in humans or cats. For sheep, Toxovax® has been put on the market in the last few years and has had a major impact on the farming economy and consumption of meat products. Scientists urge farmers to vaccinate their whole flock since a single dose can provide lifetime protection from Toxoplasmosis for a sheep.

Toxovax® is a live-attenuated vaccine, meaning it uses a weakened version of the T. gondii parasite, specifically the S48 strain, and is not harmful to the recipient. Other vaccines you might be familiar with that are live-attenuated include the MMR and chickenpox vaccines (1). Toxovax® works to produce immunity against T. gondii by reducing tissue cyst development in ewes to prevent against abortion and barrenness. Bareness can cause great economic losses for farmers and consumers which is why scientists and economists have created the best economic moves and timing of when to vaccinate your flock to receive the greatest amount of revenue. Toxovax® has reportedly increased lamb population percentages by about 3% since the vaccine has been on the shelf. The vaccine should be administered to older sheep 3-4 weeks before mating occurs and lambs can be vaccinated as early as five months of age. In the United Kingdom, about 0-2kg of vaccine can be purchased for 4 Euros, which equals to about 4 pounds for $4.25. It is very affordable (2)!

A vaccine for cats is in the making. Scientists are looking to develop a vaccine to prevent oocyst shedding in cats so that sporulation is unable to occur and fecal matter is not as toxic (5). Numerous trials have also been made to develop a vaccine for humans. However, research shows that these products have a short shelf life and are not safe. Many people complained of strong allergic reactions to the vaccine. But there is realistic hope! A DNA vaccine has shown promise, meaning scientists are trying to combat Toxoplasmosis using genetically engineered DNA from the parasite in order to produce a gentler immune response to the disease. DNA vaccines have some distinct advantages compared with traditional vaccines in that they can elicit cellular and humoral immune responses against Toxoplasmosis (4). 

 

Sources:

1. Ltd, Iconography. “Toxovax 50 Dose.” Toxovax 50 Dose – Farmacy.co.uk. N.p., n.d. Web. 13 Dec. 2016.

2. “Toxoplasmosis TOXOVAX® Sheep Vax.” Toxoplasmosis TOXOVAX® Sheep Vax. MSD Animal Health, 2016. Web. 13 Dec. 2016.

3. “Toxovax.” Mole Valley Farmers. Mole Valley Farmers Ltd., 2016. Web. 12 Dec. 2016.

4. Wang, HL. “DNA Vaccination with a Gene Encoding Toxoplasma Gondii Rhoptry Protein 17 Induces Partial Protective Immunity against Lethal Challenge in Mice.” Parasite (Paris, France). U.S. National Library of Medicine, 3 Feb. 2016. Web. 15 Dec. 2016.

5. Liu, Qi, Lachhman Das Singla, and Huaiyu Zhou. “Vaccines against Toxoplasma Gondii: Status, Challenges and Future Directions.”Human Vaccines & Immunotherapeutics. Landes Bioscience, 01 Sept. 2012. Web. 15 Dec. 2016.