Cost-effectiveness of novel diagnostic tools for the diagnosis of tuberculosis.

SETTING: The potential cost-effectiveness of improved diagnostic tests for tuberculosis (TB) in resource-limited settings is unknown. OBJECTIVE: To estimate the incremental cost-effectiveness of a hypothetical new point-of-care TB diagnostic test in South Africa, Brazil and Kenya. DESIGN: Decision-analysis model, adding four diagnostic interventions (sputum smear microscopy, new test, smear plus new test and smear plus TB culture) to a baseline of existing infrastructure without smear. RESULTS: Adding sputum smear was estimated to be more cost-effective (incremental cost per disability-adjusted life year [DALY] of $86 [South Africa], $131 [Brazil], $38 (Kenya]) than a new TB diagnostic with 70% sensitivity, 95% specificity and price of $20 per test ($198 [South Africa], $275 [Brazil], $84 [Kenya]). However, compared to sputum smear, smear plus new test averted 46-49% more DALYs per 1000 TB suspects (321 vs. 215 [South Africa], 243 vs. 166 [Brazil], 790 vs. 531 [Kenya]), at an incremental cost of $170 (Kenya) to $625 (Brazil) per DALY averted. Cost-effectiveness was most sensitive to the specificity and price of the new test, the baseline TB case detection rate and the discount rate. CONCLUSION: Novel diagnostic tests for TB are potentially highly cost-effective. Cost-effectiveness is maximized by high-specificity, low-cost tests deployed to regions with poor infrastructure.

The raising of equine colostrum-deprived foals; maintenance and assessment of specific pathogen (EHV-1/4) free status.

Over a period of two years, a total of 22 full term foals from Welsh Mountain pony mares were raised in conditions that were free from infection by Equid herpesvirus (EHV-1/4). Parturition dates were predicted by monitoring colostrum electrolytes, and the mares allowed to foal naturally under supervision or following induction with intravenous oxytocin. Immediately following birth, foals were separated from their dams and transferred to a specially built, positive pressure isolation unit. They were given antibiotic prophylaxis and fed bovine colostrum during the first 24 h, and then mare's milk replacer until weaned. Out of 22 specific pathogen free (SPF) foals one that had not been given antibiotic prophylaxis died of an E. coli septicaemia aged eight days. Two foals developed a streptococcal upper respiratory tract infection, which responded to antibiotic therapy and did not spread to the rest of the herd. A self limiting upper respiratory tract infection was seen in a fourth foal and mild diarrhoea was observed in six foals. Physical development in all SPF foals appeared normal and behavioural patterns resembled those of conventional handreared foals. Newborn foals were held in a separate quarantine area, within the isolation unit, and checked extensively for evidence of EHV-1/4 infection, before being transferred to the main holding unit. Periodic checks were then made for EHV-1/4 over a period ranging from 2 to 4 months; none of the SPF foals showed evidence of infection with EHV-1/4 in terms of clinical disease, virus isolation, sero-conversion or specific lymphocyte transformation.