Is a HIV vaccine a viable option and at what price? An economic evaluation of adding HIV vaccination into existing prevention programs in Thailand

<p>Abstract</p> <p>Background</p> <p>This study aims to determine the maximum price at which HIV vaccination is cost-effective in the Thai healthcare setting. It also aims to identify the relative importance of vaccine characteristics and risk behavior changes among vaccine recipients to determine how they affect this cost-effectiveness.</p> <p>Methods</p> <p>A semi-Markov model was developed to estimate the costs and health outcomes of HIV prevention programs combined with HIV vaccination in comparison to the existing HIV prevention programs without vaccination. The estimation was based on a lifetime horizon period (99 years) and used the government perspective. The analysis focused on both the general population and specific high-risk population groups. The maximum price of cost-effective vaccination was defined by using threshold analysis; one-way and probabilistic sensitivity analyses were performed. The study employed an expected value of perfect information (EVPI) analysis to determine the relative importance of parameters and to prioritize future studies.</p> <p>Results</p> <p>The most expensive HIV vaccination which is cost-effective when given to the general population was 12,000 Thai baht (US$1 = 34 Thai baht in 2009). This vaccination came with 70% vaccine efficacy and lifetime protection as long as risk behavior was unchanged post-vaccination. The vaccine would be considered cost-ineffective at any price if it demonstrated low efficacy (30%) and if post-vaccination risk behavior increased by 10% or more, especially among the high-risk population groups. The incremental cost-effectiveness ratios were the most sensitive to change in post-vaccination risk behavior, followed by vaccine efficacy and duration of protection. The EVPI indicated the need to quantify vaccine efficacy, changed post-vaccination risk behavior, and the costs of vaccination programs.</p> <p>Conclusions</p> <p>The approach used in this study differentiated it from other economic evaluations and can be applied for the economic evaluation of other health interventions not available in healthcare systems. This study is important not only for researchers conducting future HIV vaccine research but also for policy decision makers who, in the future, will consider vaccine adoption.</p

Horizontal transmission of Rickettsia felis between cat fleas, Ctenocephalides felis

Rickettsia felis is a rickettsial pathogen primarily associated with the cat flea, Ctenocephalides felis. Although laboratory studies have confirmed that R. felis is maintained by transstadial and transovarial transmission in C. felis, distinct mechanisms of horizontal transmission of R. felis among cat fleas are undefined. Based on the inefficient vertical transmission of R. felis by cat fleas and the detection of R. felis in a variety of haematophagous arthropods, we hypothesize that R. felis is horizontally transmitted between cat fleas. Towards testing this hypothesis, flea transmission of R. felis via a bloodmeal was assessed weekly for 4 weeks. Rhodamine B was used to distinguish uninfected recipient and R. felis-infected donor fleas in a rickettsial horizontal transmission bioassay, and quantitative real-time PCR assay was used to measure transmission frequency; immunofluorescence assay also confirmed transmission. Female fleas acquired R. felis infection more readily than male fleas after feeding on a R. felis-infected bloodmeal for 24 h (69.3% and 43.3%, respectively) and both Rickettsia-uninfected recipient male and female fleas became infected with R. felis after cofeeding with R. felis-infected donor fleas (3.3-40.0%). Distinct bioassays were developed to further determine that R. felis was transmitted from R. felis-infected to uninfected fleas during cofeeding and copulation. Vertical transmission of R. felis by infected fleas was not demonstrated in this study. The demonstration of horizontal transmission of R. felis between cat fleas has broad implications for the ecology of R. felis rickettsiosis. © 2011 Blackwell Publishing Ltd

Data from: Horizontal transmission of Rickettsia felis between cat fleas, Ctenocephalides felis

Rickettsia felis is a rickettsial pathogen primarily associated with the cat flea, Ctenocephalides felis. Although laboratory studies have confirmed that R. felis is maintained by transstadial and transovarial transmission in C. felis, distinct mechanisms of horizontal transmission of R. felis among cat fleas is undefined. Based on the inefficient vertical transmission of R. felis by cat fleas and the detection of R. felis in a variety of hematophagous arthropods, we hypothesize that R. felis is horizontally transmitted between cat fleas. Towards testing this hypothesis, flea transmission of R. felis via a bloodmeal was assessed weekly for four weeks. Rhodamine B was used to distinguish uninfected recipient and R. felis-infected donor fleas in a rickettsial horizontal transmission bioassay and quantitative real-time PCR assay was utilized to measure transmission frequency; immunofluorescence assay also confirmed transmission. Female fleas acquired R. felis-infection more readily than male fleas after feeding on a R. felis-infected bloodmeal for 24 h (69.3% and 43.3%, respectively) and both Rickettsia-uninfected recipient male and female fleas became infected with R. felis after co-feeding with R. felis-infected donor fleas (3.3-40.0%). Distinct bioassays were developed to further determine that R. felis was transmitted from R. felis-infected to uninfected fleas during co-feeding and copulation. Vertical transmission of R. felis by infected fleas was not demonstrated in this study. The demonstration of horizontal transmission of R. felis between cat fleas has broad implications for the ecology of R. felis rickettsiosis

Dissemination of bloodmeal acquired Rickettsia felis in cat fleas, Ctenocephalides felis

Background: Cat fleas, Ctenocephalides felis, are known biological vectors for Rickettsia felis. Rickettsial transmission can be vertical via transovarial transmission within a flea population, as well as horizontal between fleas through a bloodmeal. The previously undescribed infection kinetics of bloodmeal-acquired R. felis in cat fleas provides insight into the R. felis-flea interaction. Findings. In the present study, dissemination of R. felis in previously uninfected cat fleas fed an R. felis-infected bloodmeal was investigated. At weekly intervals for 28 days, rickettsial propagation, accumulation, and dissemination in gut epithelial cells, specifically in the hindgut and the specialized cells in the neck region of midgut, were observed on paraffin sections of infected cat fleas by immunofluorescence assay (IFA) and confirmed by PCR detection of R. felis 17-kDa antigen gene. IFA results demonstrate ingested rickettsiae in vacuoles during early infection of the gut; lysosomal activity, indicated by lysosome marker staining of freshly-dissected gut, suggests the presence of phagolysosome-associated vacuoles. Subsequent to infection in the gut, rickettsiae spread to the hemocoel and other tissues including reproductive organs. Densely-packed rickettsiae forming mycetome-like structures were observed in the abdomen of infected male cat fleas during late infection. Ultrastructural analysis by transmission electron microscopy (TEM) confirmed the presence and infection characteristics of Rickettsia including rickettsial destruction in the phagolysosome, rickettsial division, and accumulation in the flea gut. Conclusions: This study intimately profiles R. felis dissemination in cat fleas and further illuminates the mechanisms of rickettsial transmission in nature. © 2013 Thepparit et al.; licensee BioMed Central Ltd

Table S1.

Raw data for gene copy numbers of (a) R. felis 17-kDa and (b) C. felis 18S rDNA in individual flea samples from rickettsial horizontal transmission bioassay. In three independent trials, individual fleas were assessed by qPCR for R. felis infection at day 1, 7, 14, 21 and 28 post co-feeding. (a) R. felis 17-kDa gene copy number quantities per individual flea lysate were extrapolated based on their position relative to the standard curve. (b) C. felis 18S rRNA gene copy number quantities per individual flea lysate were also determined by extrapolating their values based on their position relative to the standard curve. C. felis 18S rDNA counts were performed for all positive Rf17-kDa fleas. The values in the above tables were log transformed and ratios of logRf17kDa/logCf18SrDNA were generated for individual flea samples (results presented in main text)

LONG-TERM DETERMINATION OF AIRBORNE RADON PROGENY CONCENTRATIONS USING LR 115 DETECTORS AND THE EFFECTS OF THORON

INTERNATIONAL WORKSHOP on the ENVIRONMENTAL THORON AND RELATED ISSUE

LONG-TERM DETERMINATION OF AIRBORNE RADON PROGENY CONCENTRATIONS USING LR 115 DETECTORS AND THE EFFECTS OF THORON

INTERNATIONAL WORKSHOP on the ENVIRONMENTAL THORON AND RELATED ISSUE

UCCE efforts improve quality of and demand for fresh produce at WIC A-50 stores

In 2005, the Institute of Medicine recommended major revisions in the food packages provided by the federal Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), leading to new regulations that allow participants to purchase a wide variety of fruits and vegetables with their vouchers. In support of this policy change, UC Agriculture and Natural Resources Cooperative Extension (UCCE) developed educational materials to promote fresh produce among WIC participants and offered postharvest handling training at WIC-only stores, known as A-50 vendors, in order to improve produce quality. A survey conducted after the educational sessions found that WIC participants had increased knowledge of produce and A-50 vendors showed improved postharvest handling after the education sessions. This research demonstrates that combining nutrition education with postharvest handling curriculum can lead to a successful educational program that supports increased demand among WIC participants for fresh produce