DONALD KNOWLES: "Once a cow is infected with this parasite, all the data indicates that the cow stays infected for life. And the consequences of that, the big deal about that is, that means that cow, even a cow that has been vaccinated, now it’s protected against the disease, but it can still transmit. See it’s infected for life. And so that animal is still a source of transmission."
And that is not the only problem with this method of vaccination.
DONALD KNOWLES: "One of the things in using live vaccines is that they usually require cold storage. And that adds to the cost of it, and also adds to the difficulty of using it in places like Africa."
For more than four years, American and Kenyan scientists have studied diseases carried by ticks. The scientists in the United States centered their work on the parasite that causes Texas cattle fever. This fever is common to the Americas.
This year, the scientists began a new study in Africa. The study is aimed at developing a new vaccine for the East Coast fever parasite. Dr. Knowles says their goal is a vaccine that does not require infecting and treating animals or the need for cold storage.
And that’s the VOA Special English Agriculture Report, written by Jerilyn Watson. We have transcripts, MP3s and now PDFs for e-readers at voaspecialenglish.com -- VOA's daily source of news and information for people learning English. Find us on Facebook, Twitter and YouTube at VOA Learning English. I'm Doug Johnson.
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2013-11-25
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