Management and socio-economics of tsetse control

Estimation of the Costs of Living with Trypanosomiasis

Through a participatory combination of ranking and informal quantification, robust estimates of the costs of living with trypanosomiasis, and therefore the benefits of tsetse control, can in many circumstances be obtained. This page sets out a worked example, based on a real life situation.

In Konso, Ethiopia, the effects of trypanosomiasis are felt in various ways: as mortality, loss of productivity, cost of regular trypanocidal treatment, and incidence of abortion. In several villages, informants were asked to rank the different impacts of trypanosomiasis, from worst to least bad.

Table 1: Ranking of Impacts of Trypanosomiasis

The impacts that would be easiest to quantify are mortality, abortions and financial cost of trypanocidal treatment. Table 2 gives some idea of the dimensions of these through individual responses (not from randomly chosen informants) on these variables, with current herd sizes as referents.

Table 2: Individual Responses on Quantifiable Impacts of Trypanosomiasis

These figures, non-random and non-standardised, do not permit calculation of average mortality rates, but suggest that they are very high: yearly mortality rates of 25% of year-end holdings are clearly not unusual. Abortions, in accordance with the rankings in Table 1, are less significant.

Berenil costs B6-7 per sachet. In Masoya, where people took animals to a resident paravet, they were paying B6 to treat a heifer and B8 for an ox, presumably according to a strict by-weight dosage. Elsewhere, a regime of one packet per adult bovine seem to be generally used. The ratios of numbers of treatments bought in the last year to current cattle holdings range from around 0.17:1 to 3:1, or B1-B18 per head of adult cattle.

In areas where oxen are used for ploughing, a trypanosomiasis attack, even when successfully treated, leads to the loss of an ox’s draught power for at least a week, and often a month. Draft oxen are sometimes hired out in Konso, by the pair, with equipment and the services of the owner. There are also customs of exchange of ox for human labour (see Box 1).

Depending on whether ploughing takes place in the long and short rains (Baidi-Fuchucha, Masoya, or the long rains only (Abaroba), oxen may work, usually on a five- or six-day week basis, for anything between two months and five months a year.

There is very little trade in milk or buttermilk, but a small trade in butter. A trypanosomiasis attack, even when successfully treated, leads to an almost complete loss of milk and butter for human consumption for the rest of the lactation period. Some informants said that even after successful treatment there would not be enough milk to ensure the survival of the calf. Butter is accumulated over a few days, and sold in gourds or solid lumps of various sizes. Varying informant accounts of these prices and the number of cow/days they represent (cows are milked twice a day) are given in Box 2. Informant views on lactation periods and calving intervals are given in Box 3.

It is possible, with a number of very questionable assumptions, to arrive at overall financial costs of trypanosomiasis. This is done, using very conservative assumptions, in Box 4.

This figure should be compared to the cost of pour-on. If pour on is administered to half the herd (as seems to be the current recommendation, accepted in principle by cattle owners) the cost varies with the frequency of administration

Table 3: Costs of Pour-On Regime (Birr per adult animal in herd per year)

The cost of trypanosomiasis above is therefore slightly lower than the cost of pour-on administered to half the herd five times a year, and considerably lower than the cost of the technically more appropriate regime of seven applications per year.

However:

• The above calculation uses a conservative mortality rate, which is the biggest single component of the cost of trypanosomiasis.

• It uses a conservative rate of infections treated per year at 0.5 per animal, whereas many informants recorded up to three.

• It uses a low rate of ox utilisation, whereas in some areas oxen are used for 5 months per year or more (40%), and a low assumption of work days lost to infection. Additionally, Table 1 shows that in many areas loss of ploughing is seen as more important than direct costs of treatment.

• It does not factor in abortions/increases in calving intervals, treatment of aborted cattle, or costs of time spent searching for treatment.

Using a mortality rate of 10%, a rate of infections per animal of one, a rate of ox utilisation of 40% and an assumption of ploughing days lost to infection of 10 days (still fairly conservative assumptions given our information), the overall cost per adult animal emerges as:

Mortality 30.0
Direct cost of treatment 6.0
Loss of ploughing 9.6
Loss of milk 6.0
TOTAL 51.6 Birr

or over twice the cost per animal of a five-application regime, and considerably more than a seven-application regime.