Assessment of E. coli and Salmonella spp. infection risks associated with different fecal sludge disposal practices in Thailand.

The proper management of fecal sludge (FS), to block the transmission pathways of pathogens, is rarely enforced in many parts of the world. Health risks associated with different disposal practices of FS in peri-urban settings of a large metropolis in Thailand were assessed; Tha Klong sub-district with indiscriminate FS dumping, and Klong Luang sub-district which has an FS treatment system. The study showed that indiscriminate FS dumping from along the canal banks and discharge of market waste were likely the major sources of E. coli and Salmonella spp. in contamination of the canal water. The increased microbial pathogen concentrations near the FS treatment facility also indicated contamination risks from poorly designed treatment facilities. Quantitative microbial risk assessment (QMRA) indicated very high water-related infection risk levels compared to the actual locally recorded disease occurrences. These results indicated that the QMRA model needs to be modified to take account of immunological differences between populations in developed countries, where the model was developed, and developing countries. In addition, further sensitivity factors are needed to reflect different societal behavior patterns, and therefore contact with potentially contaminated water, in different sub-populations of many less developed communities.

Determining the cost-effectiveness of mass screening for cervical cancer using common analytic models.

OBJECTIVE: To estimate the cost per life-year saved (cost-effectiveness ratio [CER]) for cervical cancer and to evaluate the influence of the decreased incidence upon the cost per life-year saved. STUDY DESIGN: We established hypothetical cohorts at 10-year intervals between 30 and 79 years of age, each of which consisted of 100,000 asymptomatic female subjects, and estimated the cost and effect of single mass screening for cervical cancer. To investigate the influence on CER, we performed a sensitivity analysis of each item, including the consultation rate for further examination, prevalence rate and cost of medical treatment. RESULTS: The estimated CER per one expected life-year of survival was lowest for subjects in their 30s and highest for those in their 70s. The difference between the two was more than five-fold. Sensitivity analysis was rarely affected by changes in the cost of medical treatment and the prevalence rate, but the effectiveness rate could be fairly affected by the consultation rate for closer examination. CONCLUSION: Mass screening for cervical cancer is acceptable in terms of economic effectiveness. Moreover, mass screening for cervical cancer could decrease the morbidity rate for scores of years thereafter.

Cost-effective analysis of mass screening for cervical cancer in Japan.

Cost-effectiveness analysis for cervical cancer screening in Japan was performed to estimate the cost per life-year saved by the screening; cost-effectiveness ratio (CER). The analysis was made using a simulation model to estimate long-term cost and effectiveness of the screening programs. CER of cervical cancer screening was estimated to be US$ 40,604 which was 2.4 times more expensive than that for gastric cancer screening but was about the same as that for colorectal cancer screening. It was within the range of cost-effectiveness of other cancer screening programs financed under the Health and Medical Services Law for the Aged in Japan. We performed sensitivity analysis on the following seven estimates, the screening charge, the sensitivity and the specificity of the screening test, the frequency of carcinoma in situ (CIS) among cases detected in the screening program, the initial cost and the terminal cost for patients with invasive cancer, and the incidence rate of cervical cancer. The sensitivity analysis demonstrated that the screening charge was the most influential factor on CER. CER was fairly stable under various assumptions on the accuracy of the screening test, the frequency of carcinoma in situ (CIS), the treatment cost for patient, and the incidence of cervical cancer. CER was less sensitive to the changes in incidence, even to as low as a 50% decrease of the current figure. Then if the incidence rate becomes 85% of the current figure in 2015, CER would be US$ 48,176 and it was suggested that the cervical cancer screening would remain reasonably cost-effective until the year 2015.