Scabies and impetigo in Samoa: A school-based clinical and molecular epidemiological study

Ruellia angustiflora (Nees) Lindau ex Rambo: extraction and characterization of phenolic compounds and evaluation of antiradical, photoprotective and antimicrobial activities

Ruellia angustiflora is a shrub popularly known as flower of fire, used in traditional medicine as a healing agent. This study aims to verify the presence of characteristics of pharmaceutical interest in extracts from the root, stem and leaves of this species. The ideal time for ultrasound-assisted extraction is 60 min with a solid-liquid ratio of 1% (w/v). The kinetics of the reaction of the extracts with DPPH is biphasic, and IC50 values are related to the total phenolic compounds. Five phenolic compounds were identified in the extracts, where ferulic acid, rutin and quercetin showed to be the main responsible for the antiradical activity. The extracts displayed considerable photoprotective activity, mainly Ra-LE (SPF = 23). Ra-RE showed an inhibition halo similar to erythromycin against Streptococcus pyogenes. Taken together, these data reveal that Ruellia angustiflora is a source of phenolic compounds and has relevant antiradical, photoprotective and antibacterial activities.

Prevalence and determinants of impetigo in Ghana: a cross-sectional study

INTRODUCTION

Skin diseases such as impetigo pose a significant public health challenge in low resource settings. Despite this, there is a dearth of epidemiological data on the prevalence of this condition in Ghana.

METHODS

We conducted a cross sectional study in three settings in Ghana: community members in East Mamprusi district in the North East region, a secondary school in Sekyere East district, and inmates of the Kumasi central prisons both in the Ashanti region. Following a period of training, we performed a standardised skin examination on each participant to assess for scabies and impetigo. We calculated the prevalence of each skin condition and investigated determinants of impetigo.

RESULTS/ FINDINGS

Of the 1327 participants [males 64.1% and median age 22 (16-29) years], 746 (56.2%) had scabies and 186 (14%) had impetigo which was usually very mild or mild in severity. Most participants with impetigo also had scabies (161/186, 86.6%). Having an itch [RR 6.05 (95% CI 2.53-14.47)], presence of scabies burrows [RR 1.99 (95% CI 1.54-2.59)], clinical scabies [RR 3.15 (2.11-4.72)] or being in preschool [RR 4.56 (1.78-11.67)] increased the risk for impetigo. A combination of the presence of clinical scabies, age, sex and itch most accurately predicted the odds of having impetigo.

CONCLUSIONS

There is substantial burden of impetigo and scabies in Ghana. There is a need to institute measures to improve detection and control of these common dermatoses as part of Universal Health Coverage package to reduce the scourge of the diseases in this setting.

Prevalence of scabies worldwide-An updated systematic literature review in 2022

Scabies is a World Health Organization-defined neglected tropical disease, with continuously rising incidence worldwide in recent years. The aim of this study was to provide an update of the worldwide prevalence and new treatment approaches of scabies in population-based settings. MEDLINE (PubMed), Embase and LILACS databases were reviewed for English and German language population-based studies from October 2014 to March 2022. Two authors independently screened the records for eligibility, extracted all data and one critically appraised the quality of the studies and risk of bias. Systematic review registration: PROSPERO CRD42021247140. Overall, 1273 records were identified through database searching, of which 43 studies were included for the systematic review. Most of the studies (n = 31) examined the scabies prevalence in medium or low human development index countries. The highest prevalence of scabies reported in the general population (children and adults) was recorded in five randomly selected communities in Ghana (71.0%), whereas the highest scabies prevalence in studies, which only examined children (76.9%), was recorded in an Indonesian boarding school. The lowest prevalence was recorded in Uganda (0.18%). The systematic review highlights the prevalence of scabies worldwide, showing that scabies is still a serious, increasing disease that occurs globally and is clustered in developing countries. More transparent data on scabies prevalence are needed to identify risk factors to find new prevention measures.

Characterization of a novel galectin in Sarcoptes scabiei and its role in regulating macrophage functions

Sarcoptes scabiei (S. scabiei) endangers human and other mammalian health. There has been limited research into S. scabiei pathogenic mechanisms and the immunological interaction between S. scabiei and hosts. Galectins have critical roles in biological processes such as cell adhesion, signal transduction, and immune response mediation. Galectins of S. scabiei (SsGalectins) were cloned, expressed, and identified, and their transcriptional levels in S. scabiei were measured at various developmental stages. Fluorescent tissue localization was performed on SsGalectins of S. scabiei and scabies skin. A mouse AD model was constructed to evaluate the effect of rSsGalectins on skin pathogenic changes. Quantitative polymerase chain reaction and enzyme-linked immunoassay were used to identify macrophage polarization-related components and investigate the immunoregulatory effect of rSsGalectins on mouse macrophages. The results demonstrated that the S. scabiei infection causes macrophage infiltration in the scabies skin. The rSsGalectins displayed strong reactogenicity, and distinct genes of the SsGalectins were differently expressed in different developmental stages of S. scabiei. Fluorescence tissue localization revealed that the SsGalectins were mainly in the mouthparts, intestines, and body surface. Additionally, S. scabiei could secrete SsGalectins into the infected skin, proving that SsGalectins were excretion and secretion proteins of S. scabiei. In the mouse atopic dermatitis model, cutaneous macrophage infiltration and inflammation increase after rSsGalectins injection. Simultaneously, when rSsGalectins acted on bone marrow-derived macrophages, M1 macrophage-related polarization factors IL-1β, IL-6, and inducible nitric oxide synthase all increased, demonstrating that rSsGalectins can induce M1 polarization and produce pro-inflammatory cytokines. In conclusion, the SsGalectins are involved in the pathogenic process of S. scabiei by regulating the polarization of host macrophages to the M1 type when S. scabiei invade the host and promoting the incidence and development of the host's inflammatory response. This study offers fresh light on the pathogenic process of scabies mites, investigates the immunological interaction mechanism between S. scabiei and the host, and offers new insights into S. scabiei prevention and therapy.

Scabies prevalence after ivermectin-based mass drug administration for lymphatic filariasis, Samoa 2018-2019

BACKGROUND

Scabies is a common skin infestation caused by the Sarcoptes scabei mite. Ivermectin, one of three drugs used in mass drug administration (MDA) for lymphatic filariasis, is also effective for treating scabies. Ivermectin-based MDA was first conducted in Samoa in August 2018, with ivermectin being offered to those aged ≥5 years. Here, we report scabies prevalence in Samoa after MDA.

METHODS

We conducted household surveys 1.5-3.5 months (Survey 1) and 6-8 months (Survey 2) after the 2018 MDA in 35 primary sampling units. We conducted clinical examination for scabies-like rash and used International Alliance for the Control of Scabies classification criteria. We estimated scabies prevalence by age, gender and region. Multivariable logistic regression was used to assess factors associated with prevalence.

RESULTS

We surveyed 2868 people (499 households) and 2796 people (544 households) aged 0-75 years in Surveys 1 and 2, respectively. Scabies prevalence increased from 2.4% (95% CI 2.1-2.7%) to 4.4% (95% CI 4.0-4.9%) between surveys. Scabies was associated with younger age (0-4 years: aOR 3.5 [2.9-4.2]; 5-15 years: aOR 1.6 [1.4-1.8] compared to ≥16 years), female gender (aOR 1.2 [95% CI 1.1-1.4]; region (aOR range from 1.4 [1.1-1.7] to 2.5 [2.1-3.1] between regions), large households (aOR 2.6 [2.0-3.4] households ≥13), and not taking MDA in 2018 (aOR 1.3 [95% CI 1.1-1.6]).

CONCLUSIONS

We found moderate prevalence of scabies in two population-representative surveys conducted within 8 months of the 2018 MDA for lymphatic filariasis. Prevalence appeared to increase between the surveys, and ongoing surveillance is recommended, particularly in young children.

Microbial Contamination Survey of Environmental Fresh and Saltwater Resources of Upolu Island, Samoa

Analysis of microbe diversity in freshwater resources and nearshore seawater samples of Upolu Island was performed to investigate the distribution of harmful bacteria. For this, 124 samples were collected from 23 river systems, two volcanic lakes, and 45 locations inside and outside the barrier reef of Upolu Island, Samoa. Physicochemical parameters for general water quality, detection of coliform bacteria and 16S rRNA amplicon sequencing were performed on all samples. Fecal indicator bacteria (FIB) testing indicated a wide distribution of coliform bacteria in all sampled freshwater sites with evidence of fecal coliform in most locations. Importantly, evidence of coliform bacteria was found in most seawater samples inside and along the reef, apart from those samples taken ~20 km offshore. Illumina 16S rRNA amplicon sequencing of the V4 hypervariable region confirmed the presence of various types of harmful bacterial species, namely from the Enterobacteriaceae, Enterococcae, Streptococcaceae, and Vibrionacea families. By combining the sensitivity of FIB testing and next-generation sequencing, we were able to show the extent of potential contaminations in fresh and seawater samples and simultaneously identify the potential pathogenic bacterial genera present. The wide distribution of potential harmful bacteria from river runoff or direct sewage dumping has an impact on human health, leading to many skin and intestinal diseases, and is potentially detrimental to coral reef community health.