Title:
Seeking a Better Way for African Farmers to Fight a
Fever
Description: This is
a VOA Special English Agriculture Report.
See text below
Text:
East Coast fever kills hundreds of thousands of
cattle in eastern and central Africa every year. The
animals become infected when they get bitten by
ticks carrying the parasite that causes the disease.
A parasite is an organism that feeds on other
organisms. Donald Knowles directs the animal disease
research unit in the Agricultural Research Service,
part of the United States Department of Agriculture.
The service is working with the International
Livestock Research Institute in Kenya to find better
ways to prevent parasitic diseases in cattle. Dr.
Knowles is also a professor at Washington State
University. He points out that East Coast fever is
not a contagious disease, so animals cannot give it
to each other. "You need a tick to transmit from one
infected cow to the other. They won't transmit just
by standing next to each other. You need a tick to
move it between them." Farmers in parts of Africa
use a vaccination method against East Coast fever
known as infect and treat. First they infect animals
with live parasites. Then they treat them with drugs
to help them recover. That way, explains Dr.
Knowles, the animal becomes immunized or vaccinated
against a full case of the deadly fever. But there
are problems with this method of vaccination.
Uninfected ticks that bite the vaccinated animal can
still get infected and spread the parasite to other
animals. Dr. Knowles says: "Once a cow is infected
with this parasite, all the data indicates that the
cow stays infected for life ... 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 there
are other problems with this method of vaccination.
"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. For VOA Special
English, I'm Alex Villarreal.
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Hi. I
personally reviewed this video and found it appropriate for
the news section of English Global Group. This
is a Voice of America video which covers an interesting
topic in Special English. I would appreciate some feedback from both
students and teachers about this video. You can comment in
the window below using any of a number of different services
including Facebook, Yahoo, AOL, and Hotmail.
