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Ticks and Tick Borne Diseases
Major TBDs and their vectors present in the Sub Saharan region are Theileriosis, which is
transmitted by Rhipicephalus appendiculatus, and R. zambeziensis; Babesiosis and
Anaplasmosis transmitted by Boophilus microplus and B. decolaratus and Cowdriosis
transmitted by Amblyomma variegatum and A. hebraeum. These diseases have been very
devastating in the region and yet they can effectively be controlled by tick control and to
some extent through special infection and treatment immunization regimens. Although dip
tanks exist in most of the TBDs affected areas, 75% of them are poorly managed and there is
rampant development of resistance of the tick vectors to some or most of the acaricides in use
due to exposure to suboptimal doses and/or due to the use of substandard acaricides. The
actual extent of this problem is not well elucidated but there is no doubt that such a problem
may be existent and contributing to recurrence of the TBDs experienced in most of these
areas year in and year out. The impact of climatic change on TBDs vector numbers and
subsequent upward trend in outbreaks is also not well studied.
TBD losses are attributed to disease morbidity, fatality risk, chemotherapy, acaricide use,
milk losses, weight losses, restocking, and infection & treatment control measures. TBDs are
responsible for substantial economic losses on cattle production and resource use in sub-
Sahara Africa. It is estimated that direct costs resulting from the effects of TBDs is close to
US$ US$17.7 million (Brown, 1997). Theileriosis accounts for 68% of the total loss,
Anaplasmosis and Babesiosis each account for about 13%, and Cowdriosis accounts for 6%
of the total loss. Costs associated with mortality, chemotherapy and acaricide application are
in the range of 49%, 21% and 14% of the total estimated annual losses, respectively.
Infection and treatment method, milk loss and weight loss account for about 1%, 6% and 9%
of the total annual loss, respectively. Well coordinated and well supervised diagnosis and
integrated treatment and control strategies of TBDs in the region are very necessary to
improve the livestock industry and to contribute towards poverty alleviation among the rural
communities. It is encouraging to note that Theileriosis was eradicated in South Africa in
1955 almost 54 years since it was introduced into southern Africa through importation of
cattle from Tanzania via Mozambique port of Beira. Similarly, classical ECF was eradicated
in 1954 through compulsory dipping with stringent surveillance, quarantine and slaughter
policies introduced in Zimbabwe (Anon, 1929). A milder form of cattle Theileriosis named
January disease however emerged thereafter. From the 1990s to date; Corridor disease,
heartwater and cerebral Babesiosis have also spread well beyond the traditional limits due to
a break down in control strategies linked to changing political and economic situation in the
Zimbabwe and other SADC countries.
Control strategies which depended on dipping, pasture spelling and vaccinations were
developed and have been used with variable successes. Apart from dipping, which was the
universally accepted de facto method; the other approaches have not gained wide usage.
Their use in an integrated manner, for example strategic dipping and immunization, has never
seen wide adoption. These need to be evaluated under smallholder conditions so that they can
be applied in a manner that is compatible with their resources.
Tsetse Flies and Trypanosomoses
African trypanosomes, which are mainly transmitted by tsetse flies (Glossinidae), are
extracellular protozoan haemoparasites responsible for causing sleeping sickness in man or
Nagana in livestock in Sub-Saharan Africa. Wild animals can serve as reservoirs of infection.
Both human and animal trypanosomoses have serious socio-economic implications making
the disease a major obstacle to overall development in the region (Taylor, 1998; Okomo-
Assoumou et al., 1995). Close to 30% of an estimated population of 150 million cattle and,
comparable numbers of small ruminants in 37 countries of Africa, are at risk to this disease.
Annual losses in meat production alone are estimated at US$5 billion. The economic
deprivation is exacerbated by losses in milk production, tractive power, waste products that
provide natural fuel and fertilizer and secondary products such as clothing and hides. In
addition, 50 million people are currently exposed to the risk of contracting sleeping sickness,
since 1970 the disease has even inflicted about forty tourists visiting Africa (Gideon Online,
2008).
Traditional management of Trypanosomoses has for some time relied on the use of
chemotherapeutic drugs to treat infections in livestock and insecticides to control the tsetse
vector. Because the widespread use of insecticides is environmentally damaging, attempts
have recently been made to control the disease by combining the strategic use of insecticideimpregnated
targets and screens, to reduce the tsetse populations, with chemotherapeutic
treatment for the animals that succumb to the lowered challenge. Integrated control coupled
with closes monitoring of the tsetse population and the Trypanosomoses status of livestock,
can help control the disease. However, where there is no community ownership, like in most
parts of Sub Saharan Africa, these methods can prove to be too difficult to apply.
Furthermore, relying on one or two drugs to treat infected livestock increases the possibility
that the parasites will develop resistance to the drugs.
Any buoyant economy seeks to create, disseminate and use available knowledge to enhance
its growth and development. A well planned economy therefore, harnesses and uses new and
existing knowledge to improve the productivity of agriculture, industry and services and thus
increase the overall welfare of its people. As stated in a declaration and framework for action
at the 26th General Assembly of ICSU, 30th September, 1999, for most of the projects to
succeed, there is need to attract support and cooperation between communities, holders of
traditional knowledge and scientists to explore the relationships between different knowledge
systems which are aimed at fostering inter-linkages of knowledge for mutual benefit.
Indigenous and scientific knowledge provides a critical factor needed for sustainable
development and empowerment of local communities. Integration of IKS and scientific
knowledge are a prerequisite in the development process we intend to adopt in this project.
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