Modeling schistosomiasis spatial risk dynamics over time in Rwanda using zero-inflated Poisson regression

Geographic clustering of cannabis stores in Canadian cities: A spatial analysis of the legal cannabis market 4 years post-legalisation

INTRODUCTION

Following the legalisation of non-medical cannabis in 2018, the number of cannabis stores in Canada has rapidly expanded with limited regulation on their geographic placement. This study characterised the clustering of cannabis stores in Canadian cities and evaluated the association of clustering with provincial policy and sociodemographic variables.

METHODS

Cross-sectional spatial analysis of cannabis store density in dissemination areas ('neighbourhoods', n = 39,226) in Canadian cities in September 2022. Cannabis store density was defined as the count of stores within 1000 m of a neighbourhood centre. Clusters of high-density cannabis retail were identified using Local Indicators of Spatial Autocorrelation. Associations between provincial policy (privatised vs. public market), sociodemographic variables and cannabis store density were evaluated using multivariable regression.

RESULTS

Clusters of high-density cannabis retail were identified in 86% of Canadian cities, and neighbourhoods in clusters had a median of 5 stores within 1000 m. Toronto, Canada's most populous city, had the most extreme clustering where neighbourhoods in clusters had a median of 10 stores (and a maximum of 25 stores) within 1000 m. Neighbourhoods in private versus public retail markets had a significantly higher neighbourhood-level density of cannabis stores (adjusted rate ratio [aRR] 63.37, 95% confidence interval [CI] 25.66-156.33). Lower neighbourhood income quintile was also associated with a higher neighbourhood-level density of cannabis stores (Q5 vs. Q1, aRR 1.28, 95% CI 1.17-1.40).

DISCUSSION AND CONCLUSIONS

Since cannabis was legalised, clusters of high-density cannabis retail have emerged in most Canadian cities and were more likely to form lower income neighbourhoods and in private retail markets.

Malacological Survey and Spatial Distribution of Intermediate Host Snails in Schistosomiasis Endemic Districts of Rwanda

BACKGROUND

Schistosomiasis, due to S. mansoni, is prevalent in Rwanda. However, there is a paucity of information related to the abundance, species, distribution, and infectivity of Schistosoma intermediate host snails.

METHODS

Snails were collected from 71 sites, including lakeshores and wetlands. Snails obtained were morphologically identified, and cercariae were shed using standard procedures. Cercariae were molecularly characterized using PCR. GPS coordinates were used to generate geospatial maps of snail distribution that were overlaid with geospatial distribution of schistosomiasis among pre-school children in the same areas.

RESULTS

Overall, 3653 snails were morphologically classified as Bulinus spp. and 1449 as Biomphalaria spp. A total of 306 snails shed cercariae, 130 of which were confirmed as S. mansoni cercaria by PCR. There was no significant difference in the proportion of S. mansoni cercariae in wetlands compared to lakeshores.

CONCLUSION

Rwandan water bodies harbor an important number of snails that shed S. mansoni cercariae. Furthermore, a strong spatial correlation was observed between the distribution of schistosomiasis in children and the spatial distribution of snail infectivity with S. mansoni. The presence of Bulinus spp. Suggests a potential risk of S. haematobium, although molecular analysis did not show any current transmission of this parasite.

Prevalence Mapping of Schistosoma mansoni Among Pre-school Age Children in Rwanda

Schistosoma mansoni is endemic in Rwanda, and control programs have been implemented with a special focus on school-age children (SAC), ignoring pre-school age children (pre-SAC) for which the actual prevalence of the disease is not well established. This study consisted of a cross-sectional quantitative mapping of the distribution of Schistosoma mansoni and identification of associated risk factors among pre-SAC throughout the country. The study covered all the 17 districts of Rwanda endemic for Schistosoma mansoni, with a total sample of 4,675 children enrolled from 80 purposively selected villages. The parasitological assessment of children's urine and stool samples was conducted using CCA and Kato Katz methods, respectively, for infection detection. A standard questionnaire was used to collect data on the risk factors, and geospatial assessment was performed using tablets and GPS to record geographic coordinates for plotting locations on maps using ArcGIS software. The overall prevalence of S. mansoni infection across the surveyed areas was 24 and 0.8% by CCA and Kato-Katz, respectively. Infection was significantly associated with bathing children in open water bodies. Furthermore, pre-SAC looked after by siblings (sisters) were two times as much likely to be infected compared to those looked after by mothers. Schistosomiasis control interventions are needed for pre-SAC to limit their exposure to open water bodies with expectations of adapted chemotherapy to be availed. Community-based deworming campaigns may be the best way to ensure good treatment coverage of pre-SAC in Rwanda.

Advances in microneedle-based transdermal delivery for drugs and peptides

Transdermal drug delivery is a viable and clinically proven route of administration. This route specifically requires overcoming the mechanical barrier provided by the Stratum Corneum of epidermis and vascular and nervous networks within the dermis. First-generation Transdermal patches and second-generation iontophoretic patches have been translated into commercial clinical products successfully. The current review reports different studies that aim to enhance the transdermal delivery of biopharmaceutical using microneedles and their effect on drug delivery. Microneedles (MN) are the micron-scale hybrid between transdermal patches and hypodermic syringes. Microneedles are tested and proven to show better delivery of the drugs, overcoming the drawbacks of hypodermic syringes. Multiple microneedles designs have been fabricated i.e. solid, coated, hollow, and polymer microneedles. Hollow microneedles are shorter in length but similar to hypodermic needles and have pore for infusion of liquid formulation of the drug. Solid microneedles a patch is applied after creating a hole in the skin; Drugs are coated on the surface of Coated microneedles; Polymer microneedles can be of different types like dissolving, non-dissolving or hydrogel-forming made up of polymers. Various advantages and limitations associated with the use of these techniques are discussed. Delivery of peptide and protein molecules with microneedles represents a significant opportunity for a better clinical outcome and hence value creation compared to standard injectable routes of administration. The advancement in various formulation and microfabrication techniques are currently being focused to aid the delivery of protein drugs via microneedles. The most recent advances and limitations in Microneedles -mediated protein and peptide delivery were discussed.