Some limiting factors for the toxoplasma is that its influence on the host cells is stronger in a weak immune system and is quantity-dependent, so a large number of T. gondii per host cell cause a more severe effect. The effect on the host also depends on the strength of the host immune system. Immunocompetent individuals do not normally show severe symptoms or any at all, while fatality or severe complications can result in immunocompromised individuals.Since the parasite can change the hosts immune response, it may also have an effect, positive or negative, on the immune response to other pathogenic threats. This includes, but is not limited to, the responses to infections by Helicobacter felis, Leishmania major, or other parasites, such as Nippostrongylus brasiliensis. Transmission
Toxoplasmosis is generally transmitted through the mouth when Toxoplasma gondii oocysts or tissue cysts are accidentally eaten. Congenital transmittance from mother to fetus can also occur. Transmission may also occur during the solid organ transplant process or hematogenous stem cell transplants.Oral transmission may occur through:

Ingestion of raw or partly cooked meat, especially pork, lamb, or venison containing Toxoplasma cysts: Infection prevalence in countries where undercooked meat is traditionally eaten has been related to this transmission method. Tissue cysts may also be ingested during hand-to-mouth contact after handling undercooked meat, or from using knives, utensils, or cutting boards contaminated by raw meat. Ingestion of unwashed fruit or vegetables that have been in contact with contaminated soil containing infected cat feces.
He was unaware that, in 1916, Freund had correctly observed that these pigmentation effects were due to sun exposure after the use of Eau de Cologne, a perfume infused with bergamot oil. It is now known that bergamot oil contains a significant amount of bergapten, a linear furanocoumarin that gets its name from the bergamot orange. In 1937, dermatitis from Heracleum mantegazzianum was reported by Miescher and Burckhardt who suspected the possibility of light sensitization. A few years later, Kuske confirmed this hypothesis. In 1942, Klaber introduced the term "phytophotodermatitis" to emphasize that both plants and light were required to affect a reaction.Darrell Wilkinson, a British dermatologist, gave an accurate description of the disease in the 1950s. In 1961, Efremov reported 357 cases of phytophotodermatitis from Heracleum dulce (sweet cow parsnip). He "noted the requirement for sunlight in evoking the dermatitis since inunction of the juice of the plant without exposure to sunlight was harmless." Between 1962 and 1976, numerous reports of phytophotodermatitis from giant hogweed (Heracleum mantegazzianum) were reported. By 1980, the photosensitizing effects of various plant species had become well known (as evidenced by the comprehensive work of Mitchell and Rook). See also
List of cutaneous conditions
Photodermatitis
Psoralen
Photosensitivity in humans
Stinging plant, plants with fragile silica hairs that inject venoms

References
External links
 Media related to Phytophotodermatitis at Wikimedia Commons