这是我从connell feline health center 转过来的文章.我只转大家比较感兴趣的关于人从猫感染到弓型虫的部分.有兴趣的可以去看原文
http://www.vet.cornell.edu/fhc/brochures/toxo.html
没时间全读的同学,我就说重要的几点:
1.猫一生中只有几天会排虫卵
2.猫毛上通常不携带虫卵
3.猫通常在初次感染弓型虫后3-10天内开使排虫卵(通过粪便),持续大约10-14天.
4.猫刚排出的虫卵没有感染性,虫卵需要1-5天的孵育时间后才能感染人或其他的动物
(ZT)
What causes toxoplasmosis?
The life cycle of Toxoplasma gondii is complex and involves two types of host—definitive and intermediate. Cats, both wild and domestic, are the only definitive hosts for Toxoplasma gondii. This means that the parasite can only produce oocysts (eggs) when infecting a cat. When a cat ingests an infected prey (or other infected raw meat) the parasite is released into the cat’s digestive tract. The organisms then multiply in the wall of the small intestine and produce oocysts during what is known as the intraintestinal infection cycle. These oocysts are then excreted in great numbers in the cat’s feces. Cats previously unexposed to T. gondii will usually begin shedding oocysts between three and 10 days after ingestion of infected tissue, and continue shedding for around 10 to 14 days, during which time many millions of oocysts may be produced. Oocysts are very resistant and may survive in the environment for well over a year.
Other animals, including humans, are intermediate hosts of Toxoplasma gondii. These hosts can become infected but do not produce oocysts. Oocysts passed in a cat’s feces are not immediately infectious to other animals. They must first go through a process called sporulation, which takes one to five days depending on environmental conditions. Once sporulated, oocysts are infectious to cats, people, and other intermediate hosts. Intermediate hosts become infected through ingestion of sporulated oocysts, and this infection results in formation of tissue cysts in various tissues of the body. Tissue cysts remain in the intermediate host for life and are infectious to cats, people and other intermediate hosts if the cyst-containing tissue is eaten.
Can I “catch” toxoplasmosis from my cat?
Because cats only shed the organism for a few days in their entire life, the chance of human exposure is small. Owning a cat does not mean you will be infected with the disease. It is unlikely that you would be exposed to the parasite by touching an infected cat, because cats usually do not carry the parasite on their fur. It is also unlikely that you can become infected through cat bites or scratches. In addition, cats kept indoors that do not hunt prey or are not fed raw meat are not likely to be infected with T. gondii.
In the United States, people are much more likely to become infected through eating raw meat and unwashed fruits and vegetables than from handling cat feces.