Tsetse and trypanosomiasis control unit.
Tsetse flies feed exclusively on blood. It’s during feeding that infected tsetse flies transmit parasites that cause sleeping sickness in man and nagana in livestock. The common name for the disease is Trypanosomiasis. Without treatment, the disease is fatal. The disease impacts negatively on production through abortions, weight loss, reduced milk yield, loss of manure and draft power and mortality. The result is reducing herd size and general agriculture productivity of households. This brings poverty and problems of nutrition, health, education and general livelihood right from household to national level. Presence of tsetse flies creates pressure on land use resulting in accelerated land degradation through overgrazing and absence of crop rotation. The map below shows the Tsetse distribution in Zambia; The Tsetse and Trypanosomiasis Control Section is a government wing mandated to manage trypanosomiasis through control of Tsetse flies. The section pursues this through investigative surveys/studies, and application of intervention measures.
(Image for the map goes here)
Tsetse investigative operations
In investigative studies, the presence of tsetse flies is detected through use of survey methods which broadly fall into mobile and stationery categories. Investigative studies are important for the understanding of population dynamics and make informed operational decisions. Examples of commonly used mobile and stationery methods are shown below;
Black-screen fly rounds and trapping (Epsilon trap), respectively
Tsetse Control Operations
Tsetse control operations have been carried out in many parts of the country especially in livestock rearing areas. Before 1975 environmentally unfriendly methods such as bush clearing and game elimination were used to control tsetse flies in Zambia. Further persistent insecticides such as DDT and ENDOSULPHAN were also used. From the 1980s research in Zambia and many other countries developed environmentally friendly methods which are currently in use.
They include bait technology such as;
- Non-persistent insecticide impregnated odour baited screens (targets-below: used most recently in Muyombe (2012) and Mulobezi (2015)
- Treatment of livestock with insecticide (pour-on) – routine among farmers.
- Night-time aerial spraying – used in 2009 over 5,000km sq in Shangombo and over 6,300km sq in Mulobezi in 2014.
These methods use non-residual insecticides that are highly selective against tsetse flies. Other methods not yet used in Zambia include the Sterile Insect Technique (SIT) and biological control (parasitoids). To sustain gains from tsetse control area-wide control approaches that target whole tsetse belts are now promoted as advocated by PATTEC.
Below are images showing Tsetse Control Methods; the Night-time aerial spraying and the Pour-on methods.
Impact of tsetse control interventions on the environment
Except for the sterile insect technique (SIT) and use of parasitoids which have relatively little or no effects on the environment, all the other control methods impact on the environment by use insecticides. Insecticides affect non-target organisms in areas of their application leading to biodiversity loss. High biodiversity is important for the stability of communities. Elimination of tsetse flies relieves pressure on land and decelerates its degradation. However, unregulated settlement in tsetse freed areas leads to deforestation.
Advancements in tsetse control and survey technologies have incorporated environmental mitigation measures. For example, the bait technology is relatively selective in its mode of action as it is designed to selectively kill tsetse species more than other species through controlled insecticide dosages and chemical attractants used. Aerial spraying further spares other species relatively through the application of the insecticide at intervals that do not affect their life cycle as much as it does for tsetse flies. Click the link below to view the map.
For further information contact;
Ministry of Fisheries and Livestock
Department of Veterinary Services
Tsetse and Trypanosomiasis Control
P.O Box 35001, Chilanga
Tel: 211 278537