Cost-effectiveness of trachoma control in seven world regions.

BACKGROUND/AIMS: The fight against blinding trachoma is being addressed with an integrated strategy of surgery, antibiotics, hygiene promotion, and environmental improvement-the SAFE strategy, but its cost-effectiveness is largely unknown. This paper estimates the cost effectiveness of surgery and antibiotics in trachoma-endemic areas in seven world regions. METHODS: A population model was applied to follow the lifelong impact on individuals receiving trachoma control. Intervention costs and effectiveness estimates were based on a combination of primary data collection and literature review. RESULTS: Providing trichiasis surgery to 80% of those who need it would avert over 11 million DALYs per year globally, with cost effectiveness ranging from I$13 to I$78 per DALY averted across regions. Mass antibiotic treatment of all children using azythromycin at prevailing market prices would avert more than 4 million DALYs per year globally with cost-effectiveness ranging between I$9,000 and I$65,000 per DALY averted. The intervention is only cost-effective if azythromycin is donated or becomes available at reduced prices. Mass treatment of all children with tetracycline and targeted treatment with azythromycin are not cost-effective. CONCLUSIONS: As individual components of the SAFE strategy, trichiasis surgery for trachoma is a cost-effective way of restoring sight in all epidemiological sub-regions considered, as is the use of azythromycin, if donated or at reduced prices. Large study uncertainties do not change study conclusions. The results should be interpreted in the context of the overall SAFE strategy to address issues of sustainability.

Epidemiological, demographic, and economic analyses: measurement of the value of trichiasis surgery in The Gambia.

AIM: Untreated trichiasis can lead to corneal opacity. Surgery to prevent the eyelashes from rubbing against the cornea is available, but many individuals with trichiasis never undergo the operation. This study estimates the cost of illness of untreated trichiasis and the willingness to pay for surgery and compares them with the actual cost of providing surgery. MATERIALS AND METHODS: The cost of illness estimate is based on trichiasis patient demographics. Data on the implicit price of obtaining surgery and surgical utilization in a matched pair randomized trial are used to infer individual willingness to pay for trichiasis surgery. Patients in the study paid nothing out-of-pocket for surgery; the price of obtaining surgery is the value of the individual's time needed for travel and surgery plus the price of public transportation. The cost of producing surgery was calculated from project records. RESULTS: All monetary figures are reported in 1998 US dollars. The average cost of untreated trichiasis, or the net present value of life-time lost economic productivity, was $89. Individuals facing a lower cost were more likely to undergo an operation; the inferred average willingness to pay was $1.43 (SD 0.244). Surgery cost $6.13 to provide, including $0.86 for transportation to the village. DISCUSSION: Whether the value of trichiasis surgery exceeds the cost in The Gambia depends on how the value is measured. Individuals are willing to use only limited resources to obtain surgery even though lifetime economic productivity may increase substantially. All three economic measures can be used to inform policy.

Growth of populations of lice, Damalinia ovis, on sheep and their effects on production and processing performance of wool.

Merino sheep were artificially infested with lice, Damalinia ovis, and the quantity and processing performance of the wool they subsequently produced was compared with those of wool from uninfested sheep. The experiment was conducted in a winter rainfall region of Western Australia, and was repeated yearly for three years. Louse infestation depressed clean wool production by 0.3-0.8 kg per sheep but did not affect live weight. This represented loss of income to the farmer of about $A0.72 to $A1.92 for each louse-infested sheep. The wool from lice-infested sheep, when processed into tops, yielded 4.8 to 7.2% less top and noil, than wool from uninfested sheep and the tops had a lower mean fibre length. This was estimated to cost the processor $A20.79 to $A32.20 per 100 kg of wool processed which originated from lice-infested sheep. Louse populations built up during winter, spring and early summer to reach maximum sizes during mid or late summer when the sheep were shorn and removed from the experiment. In one group of infested sheep retained for the duration of the experiment, louse populations declined after shearing each summer. It appeared that shearing may be more important in limiting growth of louse populations than climatic factors.