Fight against the tsetse fly taking shape

By Gladys Kalibbala

Many Ugandans engaged in agriculture explain that pastoralism is their major income earner although they cite Nagana disease as a hindrance.

Bright Rwamirama, the state minister for animal industry explains that more than 75% of Ugandans who live in rural areas earn their living through agriculture.

The agriculture sector contributes 21% to the country's GDP, while the livestock sub-sector accounts for about 8% of the agricultural GDP.

Uganda is also endowed with livestock, with a population of 12 million heads of cattle, 12.5 million goats, 3.4 million sheep and 3.2 million pigs, according to data released by Uganda Bureau of Statistics in 2008.

Nagana disease

Tsetse flies are known to cause diseases like sleeping sickness or trypanosomiasis (human) and Nagana (animals) which has negatively affected the fight against poverty in the country.

Minister Rwamirama explains that tsetse fly infestation is threatening half of the national herd while reports from the ministry of agriculture indicates that in Uganda about 70% of the land surface is tsetse infested.

He attributes the spread of the disease to, among several other reasons, unchecked animal movement and failure to spray animals. Tsetse transmitted trypanasomiasis occurs only in Africa in an area known as the Tsetse Belt which covers 37 countries.

“The tsetse fly is trans-boundary in nature which needs our immediate concerted action against the spread of this vector,” Rwamirama says.

He explains the affected African countries need to work together for positive results to reverse a loss of about $4bn which is incurred in animal production annually on the African continent.

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Assistant commissioner for Entomology Fredrick Luyimbazi explains how the tsetse fly trap works while the manager for Sambiya River Lodge, Beatrice Adong looks on at Murchison Falls National Park. PHOTO/Gladys Kalibbala

Interventions

For some years, the ministry has coordinated projects like ‘Creation of Sustainable Tsetse and Trypanosomiasis Free Areas’ (STATFA) – which expired – to clear flies.

Recently, it introduced “Uganda Tsetse and Trypanosomiasis Eradication Project (UTTEP) working alongside Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC)” which will soon embark on tsetse fly eradication.

Rwamirama says interventions include use of tsetse traps, sterile insect technique, pour-on drugs which kill both tsetse flies and ticks while aerial spraying will be conducted soon to eliminate flies using environment-friendly drugs.

The aerial spraying method, according to Rwamirama, has proved to be successful in countries like Botswana (Okavango delta) and some islands of Zanzibar and is said to be cost effective.

“The exercise to use a safe range of chemicals known as pyrethroids will be given to experienced pilots who did the same job in Botswana using computerized planes,” he reveals.

Fly breeding

Last year, with support from the International Atomic Agency, a tsetse fly breeding centre worth sh680m was launched at the National Livestock Research Institute (NALIRI) in Tororo district to help in the fight of flies.

Fredrick Luyimbazi, the assistant commissioner for entomology at the agriculture ministry, explains that the mass rearing centre with about 3,000 breeding female flies targets 500,000 female flies from which about 50, 000 males will be raised weekly.

“The males to be sterilized will be released into areas where we would not have achieved eradication by using conventional techniques,” he explains.

One hundred male flies will be released per square kilometer for over 52 weeks, according to Luyimbazi.

When the sterilized males get to mate with the females found in the wilderness they will not produce viable offspring. Fertilization of the eggs will not take place and the eggs will be aborted. Eventually the tsetse flies being dealt with will crash.

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Fredrick Luyimbazi from explains about tsetse flies during his tour of tsetse flies suppression exercises in Buvuma Island at Lukoma STATFA Centre. From left is the LC5 C/Person for Buvuma district, Wasswa Adrian Ddungu. PHOTO/Gladys Kalibbala

“The implementation of the sterile insect technique involves the establishment and maintenance of a tsetse fly colony from which the males will be sterilized using an Irradiator ‘Gamma Source’ and later released in the wilderness after conducting an effective tsetse suppression program using tsetse traps and aerial spraying,” he says.

The males released in the wilderness will not be able to fertilize the few females which will still be available after conventional tsetse suppression methods have been used.

How it is done

The ministry collects flies from the wild at Lukoma village in Buvuma Island. “We established a field insectary here where we maintain and feed these flies,” Luyimbazi says.  

The pupae from the field insectary are then transported to Tororo where they are incubated under the required temperatures and humidity until the flies emerge from the pupae between 28 -30 days.

A female tsetse fly gives birth to a fully grown larva every 6-10 days.

In the insectary, records are kept daily on when these larvae are laid, making it easier to know when to expect the flies to metamorphose out.  As they metamorphose, they are put into fly holding cages where they are fed daily on blood.

Interestingly, a female newborn tsetse fly will be sexually mature 48 hours into its adult life while the male will take seven days, according to Luyimbazi.

Sterilized blood is currently imported from abroad to feed these flies as arrangements are being done to procure an irradiator which will be used to process blood locally.

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Minister Bright Rwamirama (centre) listens on to how the tsetse flies are multiplied at NARILI, Tororo. PHOTO/Gladys Kalibbala  

Caution to farmers

Rwamirama notes that spraying of animals weekly can drive off tsetseflies if farmers can embrace the method. However, farmers revealed that the pour-on drugs at a cost of shs80,000 per litre is too high for them. He also warned farmers about using tsetse traps in squeezing the local brew known as Kwete.

“It’s dangerous because these traps are treated in strong insecticide,” he said.

Good news

A loan amounting to $US19.7m from The Arab Bank for Economic Development in Africa (BADEA) was recently approved for Uganda to help in fighting tsetse flies. This took place in June 2013 at a conference in Sudan during the AU African ministers meeting where 13 countries were represented.

An area of 29 districts in south eastern Uganda will be sprayed in five years using these funds. These are Kalangala, Mukono, Buikwe, Buvuma, Kayunga, Jinja, Iganga, Kamuli, Luuka, Kaliro, Buyende, Tororo, Busia, Bugiri, Butaleja, Namayingo, Mayuge, Paliisa, Bukedea, Serere, Ngora, Wakiso, Amolatar, Kaberamaido, Namutumba, Soroti, Dokolo, Kibuku and Budaka.

The AU commissioner for rural economy and agriculture, Rhoda Tumusiime explained that the tsetse fly problem is one of the major constraints in agriculture and rural development in sub-Saharan Africa.

“Eradication of tsetse flies will unlock energies and resources towards agricultural production, productivity, food and nutrition security as well as poverty eradication,” she noted.

Meanwhile, the director general of the Arab Bank, AbdelazizKhelef noted that in the presence of tsetse flies, neither human wealth nor livestock wealth can be developed.