Eliminate all risks: A call to reexamine the link between canine scabies and rheumatic heart disease.

Rheumatic heart disease (RHD) and acute rheumatic fever (ARF) disproportionately affect individuals in low-resource settings. ARF is attributed to an immune response to Group A Streptococcus (GAS) following GAS pharyngitis and potentially GAS impetigo in which infection can be initiated by scabies infestation. The burden of ARF and RHD in Aboriginal and Torres Strait Islander people in Australia is among the highest globally. Following recent calls to include dog management programs in ARF and RHD prevention programs, we believe it is timely to assess the evidence for this, particularly since previous recommendations excluded resources to prevent zoonotic canine scabies. While phylogenetic analyses have suggested that the Sarcoptes mite is host specific, they have differed in interpretation of the strength of their findings regarding species cross-over and the need for canine scabies control to prevent human itch. Given that there is also indication from case reports that canine scabies leads to human itch, we propose that further investigation of the potential burden of zoonotic canine scabies and intervention trials of canine scabies prevention on the incidence of impetigo are warranted. Considering the devastating impacts of ARF and RHD, evidence is required to support policy to eliminate all risk factors.

One versus two doses of ivermectin-based mass drug administration for the control of scabies: A cluster randomised non-inferiority trial.

BACKGROUND: Mass drug administration (MDA) based on two doses of ivermectin, one week apart, substantially reduces prevalence of both scabies and impetigo. The Regimens of Ivermectin for Scabies Elimination (RISE) trial assessed whether one-dose ivermectin-based MDA would be as effective. METHODS: RISE was a cluster-randomised trial in Solomon Islands. We assigned 20 villages in a 1:1 ratio to one- or two-dose ivermectin-based MDA. We planned to test whether the impact of one dose on scabies prevalence at 12 and 24 months was non-inferior to two, at a 5% non-inferiority margin. RESULTS: We deferred endpoint assessment to 21 months due to COVID-19. We enrolled 5239 participants in 20 villages at baseline and 3369 at 21 months from an estimated population of 5500. At baseline scabies prevalence was similar in the two arms (one-dose 17·2%; two-dose 13·2%). At 21 months, there was no reduction in scabies prevalence (one-dose 18·7%; two-dose 13·4%), and the confidence interval around the difference included values substantially greater than 5%. There was however a reduction in prevalence among those who had been present at the baseline assessment (one-dose 15·9%; two-dose 10·8%). Additionally, we found a reduction in both scabies severity and impetigo prevalence in both arms, to a similar degree. CONCLUSIONS: There was no indication of an overall decline in scabies prevalence in either arm. The reduction in scabies prevalence in those present at baseline suggests that the unexpectedly high influx of people into the trial villages, likely related to the COVID-19 pandemic, may have compromised the effectiveness of the MDA. Despite the lack of effect there are important lessons to be learnt from this trial about conducting MDA for scabies in high prevalence settings. TRIAL REGISTRATION: Registered with Australian New Zealand Clinical Trials Registry ACTRN12618001086257.

Mass Drug Administration for the Control of Scabies: A Systematic Review and Meta-analysis.

BACKGROUND: Scabies is a neglected tropical disease of the skin that can lead to impetigo, serious secondary bacterial infections and immune-mediated diseases. Mass drug administration (MDA) has been reported in several studies to reduce the prevalence of scabies and impetigo. We aimed to assess the efficacy of MDA for scabies on scabies and impetigo. METHODS: We conducted a systematic review and meta-analysis of reports on the impact of MDA on scabies and impetigo. We included randomized control trials and observational evaluations reported from January 1970 to April 2021 and involving human participants. We searched PubMed, Ovid Medline, Embase, and Cochrane. We considered MDA as treatment intended for the whole population, regardless of individual infection status or symptoms. The main outcome assessed was the change in scabies and impetigo prevalence following MDA. This review is registered with PROSPERO (CRD42020169839). RESULTS: We identified 1110 records, of which 11 met inclusion criteria for the review and 9 were deemed suitable for meta-analysis for scabies and 4 for impetigo. Most studies were in small populations. There was a high degree of heterogeneity between studies (I2 value 96.19%). The overall relative reduction of the impact of MDA on scabies prevalence was 79%. The effect size was comparable for MDA based on ivermectin and permethrin. MDA for scabies also led to a reduction in impetigo prevalence with a relative reduction of 66%. CONCLUSIONS: MDA for scabies is highly effective in reducing the prevalence of scabies and impetigo. Further research is needed to determine the durability of impact, and the effectiveness of MDA regimens in larger populations.

The in vitro antibacterial effect of permethrin and formaldehyde on Staphylococcus aureus.

Antibiotic-resistant strains of bacteria such as methicillin-resistant Staphylococcus aureus are a threat to human health, and effective treatment options against them are needed. This study aimed to determine whether the insecticide permethrin was capable of inhibiting the growth of S. aureus or if some other component of a permethrin cream was responsible for a decrease in scabies associated bacterial infection previously observed. Ten S. aureus strains were grown in the presence of permethrin and formaldehyde both alone and in combination with percent inhibition determined by viable counts. Also, a time-kill assay was conducted on S. aureus exposed to the same conditions. Finally, the morphology of S. aureus grown in the presence of permethrin was examined by scanning electron microscopy. Bacterial inhibition by permethrin ranged from 0% to 41% whereas inhibition by formaldehyde was 100%. The time-kill curves of permethrin exposed cells were very similar to the positive growth control while the formaldehyde and combination exposure showed complete inhibition even at the 0-hr time point. The scanning electron micrographs of permethrin grown S. aureus showed healthy cocci cells with no sign of cell damage. Our results show that permethrin is not capable of inhibiting the growth of bacteria enough for it to be termed bactericidal. Formaldehyde is a known antiseptic and therefore was responsible for the antibacterial effect observed after the use of permethrin cream.

Randomized Trial of Community Treatment With Azithromycin and Ivermectin Mass Drug Administration for Control of Scabies and Impetigo.

BACKGROUND: Scabies is a public health problem in many countries, with impetigo and its complications important consequences. Ivermectin based mass drug administration (MDA) reduces the prevalence of scabies and, to a lesser extent, impetigo. We studied the impact of co-administering azithromycin on the prevalence of impetigo and antimicrobial resistance. METHODS: Six communities were randomized to receive either ivermectin-based MDA or ivermectin-based MDA co-administered with azithromycin. We measured scabies and impetigo prevalence at baseline and 12 months. We collected impetigo lesions swabs at baseline, 3 and 12 months to detect antimicrobial resistance. RESULTS: At baseline, scabies and impetigo prevalences were 11.8% and 10.1% in the ivermectin-only arm and 9.2% and 12.1% in the combined treatment arm. At 12 months, the prevalences had fallen to 1.0% and 2.5% in the ivermectin-only arm and 0.7% and 3.3% in the combined treatment arm. The proportion of impetigo lesions containing Staphylococcus aureus detected did not change (80% at baseline vs 86% at 12 months; no significant difference between arms) but the proportion containing pyogenic streptococci fell significantly (63% vs 23%, P < .01). At 3 months, 53% (8/15) of S. aureus isolates were macrolide-resistant in the combined treatment arm, but no resistant strains (0/13) were detected at 12 months. CONCLUSIONS: Co-administration of azithromycin with ivermectin led to similar decreases in scabies and impetigo prevalence compared to ivermectin alone. The proportion of impetigo lesions containing pyogenic streptococci declined following MDA. There was a transient increase in the proportion of macrolide-resistant S. aureus strains following azithromycin MDA. CLINICAL TRIALS REGISTRATION: clinicaltrials.gov (NCT02775617).

Treatment, prevention and public health management of impetigo, scabies, crusted scabies and fungal skin infections in endemic populations: a systematic review.

We conducted a systematic review of the treatment, prevention and public health control of skin infections including impetigo, scabies, crusted scabies and tinea in resource-limited settings where skin infections are endemic. The aim is to inform strategies, guidelines and research to improve skin health in populations that are inequitably affected by infections of the skin and the downstream consequences of these. The systematic review is reported according to the PRISMA statement. From 1759 titles identified, 81 full text studies were reviewed and key findings outlined for impetigo, scabies, crusted scabies and tinea. Improvements in primary care and public health management of skin infections will have broad and lasting impacts on overall quality of life including reductions in morbidity and mortality from sepsis, skeletal infections, kidney and heart disease.

Nous avons effectué une analyse systématique du traitement, de la prévention et du contrôle de santé publique des infections cutanées comprenant l'impétigo, la gale, la gale en croûte et la teigne, dans des cadres à ressources limitées où les infections cutanées sont endémiques. Le but étant d'informer les stratégies, les directives et la recherche pour améliorer la santé de la peau dans les populations qui sont touchées de manière inéquitable par les infections cutanées et leurs conséquences plus tard. La revue systématique est rapportée selon la déclaration PRISMA. Sur 1759 titres recensés, 81 études en texte intégral ont été passées en revue et les principaux résultats rapportés concernant l'impétigo, la gale, la gale en croûte et la teigne. Les améliorations apportées dans la prise en charge des infections de la peau dans les soins de santé primaires et les soins de santé publique auront des répercussions vastes et durables sur la qualité de vie en général, notamment une réduction de la morbidité et de la mortalité dues au sepsis, aux infections du squelette, aux maladies du rein et du cœur.

The Epidemiology of Scabies and Impetigo in Relation to Demographic and Residential Characteristics: Baseline Findings from the Skin Health Intervention Fiji Trial.

Scabies and associated impetigo are under-recognized causes of morbidity in many developing countries. To strengthen the evidence base for scabies control we undertook a trial of mass treatment for scabies. We report on the occurrence and predictors of scabies and impetigo in participants at baseline. Participants were recruited in six island communities and were examined for the presence of scabies and impetigo. In addition to descriptive analyses, logistic regression models were fit to assess the association between demographic variables and outcome of interest. The study enrolled 2051 participants. Scabies prevalence was 36.4% (95% confidence interval [CI] 34.3-38.5), highest in children 5-9 years (55.7%). Impetigo prevalence was 23.4% (95% CI 21.5-25.2) highest in children aged 10-14 (39.0%). People with scabies were 2.8× more likely to have impetigo. The population attributable risk of scabies as a cause of impetigo was 36.3% and 71.0% in children aged less than five years. Households with four or more people sharing the same room were more likely to have scabies and impetigo (odds ratios [OR] 1.6, 95% CI 1.2-2.2 and OR 2.3, 95% CI 1.6-3.2 respectively) compared to households with rooms occupied by a single individual. This study confirms the high burden of scabies and impetigo in Fiji and the association between these two conditions, particularly in young children. Overcrowding, young age, and clinical distribution of lesion are important risk factors for scabies and impetigo. Further studies are needed to investigate whether the decline of endemic scabies would translate into a definite reduction of the burden of associated complications.

Long Term Control of Scabies Fifteen Years after an Intensive Treatment Programme.

INTRODUCTION: Scabies is a major public health problem in the Pacific and is associated with an increased risk of bacterial skin infections, glomerulonephritis and rheumatic fever. Mass drug administration with ivermectin is a promising strategy for the control of scabies. Mass treatment with ivermectin followed by active case finding was conducted in five communities in the Solomon Islands between 1997 and 2000 and resulted in a significant reduction in the prevalence of both scabies and bacterial skin infections. METHODS: We conducted a prospective follow-up study of the communities where the original scabies control programme had been undertaken. All residents underwent a standardised examination for the detection of scabies and impetigo. RESULTS: Three hundred and thirty eight residents were examined, representing 69% of the total population of the five communities. Only 1 case of scabies was found, in an adult who had recently returned from the mainland. The prevalence of active impetigo was 8.8% overall and 12.4% in children aged 12 years or less. DISCUSSION: We found an extremely low prevalence of scabies 15 years after the cessation of a scabies control programme. The prevalence of impetigo had also declined further since the end of the control programme. Our results suggest that a combination of mass treatment with ivermectin and intensive active case finding may result in long term control of scabies. Larger scale studies and integration with other neglected tropical disease control programmes should be priorities for scabies control efforts.

Nurse-led school-based clinics for skin infections and rheumatic fever prevention: results from a pilot study in South Auckland.

AIM: To assess the acceptability and feasibility of delivering targeted primary health care in a decile one primary school setting. METHOD: A pilot public health nurse (PHN)-led clinic was set up in a South Auckland primary school (roll approximately 400). The clinic was based on a previous sore throat clinic model with modifications aimed at improving programme feasibility and effectiveness. The timely identification and treatment of Group A Streptococcal (GAS) throat infections to prevent rheumatic fever (RF), and the prevention and treatment of four skin infections (cellulitis, impetigo, infected eczema and scabies) were the focus. The pilot ran for 15 weeks from April to July 2011. Evaluation included documentation review, key school and healthcare stakeholder interviews and parent questionnaires. RESULTS: The consent rate was 92.2%. Of a total 722 throat swabs taken from 337 students, 94 were GAS positive. Ninety-eight assessments of skin conditions were completed at which 76 had a skin infection diagnosed, the most common infection being impetigo (n=46). Thirty-one skin infections were diagnosed in the first week of the pilot. PHN workload was high with a total of 539 phone calls, 137 home visits and 51 school-based parent consultations. The approach was highly acceptable to the majority of key stakeholders. Extrapolating pilot costs results in an estimated annual cost of $510 per student for the programme. CONCLUSION: It is likely to be both acceptable and feasible to take this model of delivering targeted primary health care to school aged children and use it on a larger scale. The complexity of providing this type of service should not be underestimated and it is essential that robust processes are in place to ensure smooth, safe running of such a programme. Long-term outcome evaluation will be vital to assess programme effectiveness.

Bacterial resistance and impetigo treatment trends: a review.

Impetigo is a common cutaneous infection that is especially prevalent in children. The prevalence of colonization and infection with resistant strains is continually increasing, forcing clinicians to reevaluate treatment strategies. Newer topical agents are effective in treating infections with resistant strains and may help minimize resistance and adverse effects from systemic agents. Use of topical disinfectants to decrease colonization is an important adjunctive measure. Physicians should be aware of local resistance patterns in impetigo to help guide therapy.

Effect of antenatal zinc supplementation on impetigo in infants in Bangladesh.

We sought to determine the effects of maternal zinc supplementation on skin infections among infants in poor urban areas of Dhaka, Bangladesh. A double-blind, placebo-controlled, randomized trial was conducted among 199 and 221 Bangladeshi infants whose mothers were administered 30 mg daily of zinc or placebo, respectively. The mothers received zinc supplementation from 12-16 weeks' gestation until delivery, and the infants were followed up until 6 months of age. Among the infants of mothers who received zinc supplementation during the antenatal period, 10.6% had at least 1 episode of impetigo compared with 19.6% of the infants of mothers in the placebo group (P = 0.01). Infants in the treatment group had a 54% reduction in incidence rate of episodes of impetigo when compared with infants in the placebo group (P = 0.01). The effect of zinc supplementation was more pronounced among male infants (64% reduction) and intrauterine growth restricted and low birth weight infants (73% reduction) and among infants of mothers with increased parity (60% reduction) or decreased socioeconomic status (71% reduction).

Effect of handwashing on child health: a randomised controlled trial.

BACKGROUND: More than 3.5 million children aged less than 5 years die from diarrhoea and acute lower respiratory-tract infection every year. We undertook a randomised controlled trial to assess the effect of handwashing promotion with soap on the incidence of acute respiratory infection, impetigo, and diarrhoea. METHODS: In adjoining squatter settlements in Karachi, Pakistan, we randomly assigned 25 neighbourhoods to handwashing promotion; 11 neighbourhoods (306 households) were randomised as controls. In neighbourhoods with handwashing promotion, 300 households each were assigned to antibacterial soap containing 1.2% triclocarban and to plain soap. Fieldworkers visited households weekly for 1 year to encourage handwashing by residents in soap households and to record symptoms in all households. Primary study outcomes were diarrhoea, impetigo, and acute respiratory-tract infections (ie, the number of new episodes of illness per person-weeks at risk). Pneumonia was defined according to the WHO clinical case definition. Analysis was by intention to treat. FINDINGS: Children younger than 5 years in households that received plain soap and handwashing promotion had a 50% lower incidence of pneumonia than controls (95% CI (-65% to -34%). Also compared with controls, children younger than 15 years in households with plain soap had a 53% lower incidence of diarrhoea (-65% to -41%) and a 34% lower incidence of impetigo (-52% to -16%). Incidence of disease did not differ significantly between households given plain soap compared with those given antibacterial soap. INTERPRETATION: Handwashing with soap prevents the two clinical syndromes that cause the largest number of childhood deaths globally-namely, diarrhoea and acute lower respiratory infections. Handwashing with daily bathing also prevents impetigo.