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Social Costs Socioeconomic Factors Leading to
Chemoresistance to Trypanosomiasis
By D. OUEDRAOGO et al. Université
Polytechnique de Bobo-Dioulasso (UPB) Institut
du Développement Rural (IDR)
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Outline

1. Introduction and problem statement
2. Objectives
3. Study design
4. Results and discussion
5. Conclusion

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1. Introduction and the problem

• Trypanocidal drugs are the most widely applied
  method that farmers use to treat and prevent
  trypanosomosis in sub-Saharan Africa.
• 25 to 50 million doses of trypanocides are
  administered each year to the approximately 45
  million cattle at-risk of trypanosomosis
  (Kristjanson et al. 1999 Sones 2001).

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• The efficacy of trypanocides in cattle appears to
  be threatened by the widespread development of
  resistance in trypanosomes to the two drugs
  licensed for use in WA (isometamidium, and
  diminazene Peregrine 1994).
• There is a general lack of information on the
  prevalence, distribution and impact of resistance
  to trypanocides (Geerts and Holmes, 1998), and
  ignorance about the most important factors
  leading to the development of trypanocidal
  resistance in the field.

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• On biological side
• Resistance is the loose of the sensitivity by an
  organism to a drug it is previously sensitive
  (Uilenberg 1998).
• On economic side
• Resistance appears like a waste of resources
  (many treatments without success, externalities,
  source of transaction costs, )
• Resistance is a big constraint for animal
  production in endemic area with induced effects
  on agricultural production.

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• As new trypanocides for use in cattle are
  unlikely to be developed in the near future,
  field studies to better understand factors
  influencing the prevalence, distribution and
  impact of drug resistance are required.
• This information could support strategies to
  improve the use and efficacy of currently
  available trypanocides in key production systems
  under trypanosomosis risk.

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2. Objectives of the study

• Estimate the proportion of trypanosome infections
  in cattle due to drug-resistant strains.
• Analyze the trypanocides market.
• Identify the factors leading to resistance in
  trypanosomoses.
• Make recommendations for a better use of
  trypanocides in the study area.

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3. Study design

• To better understand the occurrence, impact and
  factors influencing the development of
  trypanocidal drug resistance in the cotton belt,
  of the sub-humid zone of West Africa
  (south-western Burkina Faso, south-eastern Mali
  and northern Côte dIvoire).
• Kenedougou province of Burkina Faso

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• Team
• Entomologists
• Epidemiologists
• Biologists
• Agricultural / resources economists
• Cross sectional studies
• Characterization of tsetse challenge and
  trypanosomosis risk (block treatment)
• Mains characteristics of production systems
• Longitudinal study
• Six villages (low, medium and high level of
  resistance)

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• Modeling resistance factors
• Econometric model
• K Vector of variables
• ß, ? Vector of parameters
• µ stochastic variables
• Market study
• Trypanocides demand functions

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4. Main results and discussion

• Socioeconomic factors Age of household head
  (), education (), production systems crops
  producers / herdsmen (-), wealth level ()
• Environmental factors Tsetse flies infection
  rate (), accessibility (-), previous treatment
  failure rate (-)

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• Expenditures of trypanocidal drugs represent
  about 45 of total animal health cost.
• About 60 of trypanocides used are preventive
  ones.
• Price is higher on official market (high
  transaction costs) than on parallel markets
  (asymmetric information and hazard moral
  problems) .
• Impact on some parameters
• Mortality 10 et 26
• Milk production 10 et 40
• Performance of oxen 33
• FAO (1994) USD1-1.5 billion of loss for Africa.

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5. Conclusion

• Field studies undertaken in Kénédougou province
  provided valuable information on the widespread
  presence, but variable pattern, of trypanocidal
  drug resistance and changing patterns of
  trypanosome risk.
• The resistance cost appears to be high
• Externalities for individual and society
• Impact on productivity
• Increase of treatment cost (4-5 treatments per
  year vs. two treatments without resistance

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• This information has important implications for
  managing tsetse and trypanosomosis risk in the
  area.
• The results suggest reducing drug use in areas
  with very low risk, and helping livestock keepers
  to improve tsetse control and minimize
  trypanocidal drug use in higher risk areas.

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• To tackle the complexity of trypanosomosis, it is
  necessary to adopt multidisciplinary approach.
• The results presented here are preliminary ones.
  An ongoing study try to evaluate the total cost
  of the resistance to trypanosomosis in the Cotton
  belt in West Africa.
• CIRDES, ILRI, BMZ, Free University of Berlin,
  NARS