RESUMO
(1) Background: In Cambodia, Aedes albopictus is an important vector of the dengue virus. Vector control using insecticides is a major strategy implemented in managing mosquito-borne diseases. Resistance, however, threatens to undermine the use of insecticides. In this study, we present the levels of insecticide resistance of Ae. albopictus in Cambodia and the mechanisms involved. (2) Methods: Two Ae. albopictus populations were collected from the capital, Phnom Penh city, and from rural Pailin province. Adults were tested with diagnostic doses of malathion (0.8%), deltamethrin (0.03%), permethrin (0.25%), and DDT (4%) using WHO tube assays. Synergist assays using piperonyl butoxide (PBO) were implemented before the pyrethroid assays to detect the potential involvement of metabolic resistance mechanisms. Adult female mosquitoes collected from Phnom Penh and Pailin were tested for voltage-gated sodium channel (VGSC) kdr (knockdown resistance) mutations commonly found in Aedes sp.-resistant populations throughout Asia (S989P, V1016G, and F1534C), as well as for other mutations (V410L, L982W, A1007G, I1011M, T1520I, and D1763Y). (3) Results: The two populations showed resistance against all the insecticides tested (<90% mortality). The use of PBO (an inhibitor of P450s) strongly restored the efficacy of deltamethrin and permethrin against the two resistant populations. Sequences of regions of the vgsc gene showed a lack of kdr mutations known to be associated with pyrethroid resistance. However, four novel non-synonymous mutations (L412P/S, C983S, Q1554STOP, and R1718L) and twenty-nine synonymous mutations were detected. It remains to be determined whether these mutations contribute to pyrethroid resistance. (4) Conclusions: Pyrethroid resistance is occurring in two Ae. albopictus populations originating from urban and rural areas of Cambodia. The resistance is likely due to metabolic resistance specifically involving P450s monooxygenases. The levels of resistance against different insecticide classes are a cause for concern in Cambodia. Alternative tools and insecticides for controlling dengue vectors should be used to minimize disease prevalence in the country.
RESUMO
AIM: To determine the monthly treatment costs for each element of cancer care in patients receiving chemotherapy and to apportion the burden of cost by financing agent (Commonwealth, State government, private health insurer, patient). METHODS: A cohort of 478 patients (54% breast, 33% colorectal and 13% non-small-cell lung cancer) were recruited from 12 centers representing metropolitan and regional settings in public and private sectors. Primary data were linked to secondary data held in New South Wales state (Admitted Patients and Emergency Department Data) and Commonwealth (Medicare and Pharmaceutical Benefits) databases. The monthly treatment costs of each element of care and the funding agent were calculated from secondary health data. RESULTS: Across all tumor types, the mean monthly treatment cost was $4162 (10%-90% quantiles $1018-$8098; range $2853 [adjuvant colorectal] to $5622 [metastatic lung]), with 54% of this cost borne by Commonwealth government, 26% by private health insurers, 14% by State government and 6% by patients. The mean monthly costs of treating metastatic disease were $1415 greater than those for adjuvant therapy. The mean monthly costs were contributed to by inpatient care ($1657, 40%), chemotherapy prescriptions ($1502, 36%), outpatient care ($452, 11%) and administration of chemotherapy ($364, 9%). CONCLUSION: All four funders have a shared incentive to reduce absolute monthly treatment costs since their proportional contribution is relatively constant for most tumor types and stages. There are opportunities to reduce cancer care costs by minimizing the risk of inpatient hospital admissions that arise from chemotherapy administration and by recognizing incentives for cost-shifting.