Editing Tsetse fly (section)

===Current situation===

Tsetse flies are regarded as a major cause of rural poverty in [[sub-Saharan Africa]]<ref name="Vreysen-et-al-2013" /> because they prevent mixed farming. The land infested with tsetse flies is often cultivated by people using hoes rather than more efficient draught animals because ''[[nagana]]'', the disease transmitted by tsetse, weakens and often kills these animals. Cattle that do survive produce little milk, pregnant cows often abort their calves, and manure is not available to fertilize the worn-out soils.
[[File:Tsetse-BKF-2.jpg|right|thumb|Tsetse fly from Burkina Faso]]

The disease ''nagana'' or African [[animal trypanosomiasis]] (AAT) causes gradual health decline in infected livestock, reduces milk and meat production, and increases abortion rates. Animals eventually succumb to the disease - annual cattle deaths caused by trypanosomiasis are estimated at 3 million{{citation needed|date=April 2021}}, reducing annual cattle production value by US$600m-US$1.2b.<ref name="Vreysen-et-al-2013" /> This has an enormous impact on the livelihood of farmers who live in tsetse-infested areas, as infected animals cannot be used to plough the land, and keeping cattle is only feasible when the animals are kept under constant [[prophylactic]] treatment with [[trypanocidal agent|trypanocidal drugs]], often with associated problems of [[trypanocide resistance|drug resistance]], counterfeited drugs, and suboptimal dosage. The overall annual direct lost potential in livestock and crop production was estimated at US$4.5 billion<ref name="Budd, L 1999">Budd, L. 1999. DFID-funded tsetse and trypanosome research and development since 1980. Vol. 2. Economic analysis. Aylesford, UK, DFID Livestock Production, Animal Health and Natural Resources Systems Research Programmes</ref><ref>DFID. 2001. Trypanosomiasis, tsetse and Africa. The year 2001 report. Aylesford, UK, Department for International Development.</ref>-US$4.75b.<ref name="Vreysen-et-al-2013" />

The tsetse fly lives in nearly {{convert|10000000|sqkm|-6}} in sub-Saharan Africa<ref name="Vreysen-et-al-2013" /> (mostly wet tropical forest) and many parts of this large area is fertile land that is left uncultivated—a so-called [[green desert]] not used by humans and cattle. Most of the 38 countries<ref name="Vreysen-et-al-2013"/> infested with tsetse are poor, debt-ridden and underdeveloped. Of the 38<ref name="Vreysen-et-al-2013" /> tsetse-infested countries, 32 are [https://www.fao.org/countryprofiles/lifdc/en/ low-income, food-deficit countries], 29 are [[least developed countries]], and 30{{citation needed|date=April 2021}} or 34<ref name="Vreysen-et-al-2013" /> are among the 40 most [[heavily indebted poor countries]]. Eradicating the tsetse and trypanosomiasis (T&T) problem would allow rural Africans to use these areas for [[animal husbandry]] or the cultivation of crops and hence increase food production. Only 45 million cattle, of 172 million present in sub-Saharan Africa, are kept in tsetse-infested areas but are often forced into fragile ecosystems like highlands or the [[semiarid]] [[Sahel]] zone, which increases overgrazing and overuse of land for food production.

In addition to this direct impact, the presence of tsetse and trypanosomiasis discourages the use of more productive exotic and cross-bred cattle, depresses the growth and affects the distribution of livestock populations, reduces the potential opportunities for livestock and crop production (mixed farming) through less draught power to cultivate land and less manure to fertilize (in an environment-friendly way) soils for better crop production, and affects human settlements (people tend to avoid areas with tsetse flies).

Tsetse flies transmit a similar disease to humans, called [[African trypanosomiasis]], human African trypanosomiasis (HAT) or sleeping sickness. An estimated 60<ref name="Vreysen-et-al-2013" />-70<ref name="Simarro-et-al-2012">{{cite journal | title=Simarro PP, Cecchi G, Franco JR, Paone M, Diarra A, Ruiz-Postigo JA, et al. (2012). Estimating and Mapping the Population at Risk of Sleeping Sickness. PLoS Negl Trop Dis 6(10): e1859.| year=2012| doi=10.1371/journal.pntd.0001859| pmid=23145192| doi-access=free| last1=Simarro| first1=P. P.| last2=Cecchi| first2=G.| last3=Franco| first3=J. R.| last4=Paone| first4=M.| last5=Diarra| first5=A.| last6=Ruiz-Postigo| first6=J. A.| last7=Fèvre| first7=E. M.| last8=Mattioli| first8=R. C.| last9=Jannin| first9=J. G.| journal=PLOS Neglected Tropical Diseases| volume=6| issue=10| pages=e1859| pmc=3493382}}</ref> million people in 20 countries are at different levels of risk and only 3-4 million people are covered by active surveillance.<ref name="Vreysen-et-al-2013" /> The [[DALY]] index (disability-adjusted life years), an indicator to quantify the burden of disease, includes the impact of both the duration of life lost due to premature death and the duration of life lived with a disability. The annual burden of sleeping sickness is estimated at 2 million DALYs. Since the disease tends to affect economically active adults, the total cost to a family with a patient is about 25% of a year's income.<ref>Shaw, A.P.M., 2004. Economics of African trypanosomiasis. In The Trypanosomiases (eds. I. Maudlin, P.H. Holmes & M.A. Miles) CABI Publishing, 2004, pp. 369-402</ref>