At the West African Institute for Trypanosomiasis Research Field Station at Ugbobigha was 21·5 per cent.; this species is believed to be of major economic importance because its presence must prevent the keeping of cattle in large areas of potential grazing.
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Trypanosomiasis, both of humans and of livestock, is one of the most important factors restricting economic development in Africa today. The present paper outlines how this disease is limiting agricultural, veterinary and forestry development in the Sudan, Bechuanaland and West Africa.
The present tsetse-fly distribution is reviewed. Glossina palpalis and G. morsitans occur in the south Sudan and G. morsitans in the Ngamiland district of Bechuanaland; G. morsitans, G. palpalis and G. tachinoides are the most important species in West Africa.
These tsetse flies have altered the cattle distribution in all three regions and, in addition to causing widespread disease, have created local overstocking problems in the tsetse-free grazing areas, and have enforced nomadism on breeding herds and economic loss in slaughter cattle along the trade cattle routes in West Africa.
Human trypanosomiasis is not now such an urgent problem and public health measures have led to its control in all three areas.
Increased agricultural development, which can be a successful and economic method of reclaiming land from tsetse flies, must be intensified in all three areas.
Forest conservation policy comes into conflict with tsetse control measures only in West Africa.
Detailed tsetse-fly surveys and research, on which future plans can be firmly based, are now urgently required.
The correct answer is - A. A few centimeters a year.
Earth's crustal plates move very slowly, between 2 cm and 5 cm (depending on the plate) annually. This is the reason why it takes millions of years for them to significantly change their position, and with it the appearance of our planet. These crustal plates are slowly moving around the planet because they are powered by flow in the interior mantle.
