Childhood post-streptococcal glomerulonephritis as a risk factor for chronic renal disease in later life

Predictive factors of progression to chronic glomerulonephritis in pediatric patients with post streptococcal acute glomerulonephritis

BACKGROUND

Post streptococcal acute glomerulonephritis (PSAGN) patients have favorable prognosis, in which most patients showed full recovery in terms of kidney function. However, there is a slight chance ranging from 3 to 6% that PSAGN patients develop chronic kidney diseasewhich may progress into end-stage kidney disease in later life. It is important to identify the factors that can predict the development of chronic glomerulonephritis following PSAGN. Therefore, early intervention can be performed to halt the progression of chronic kidney disease. This study aimed to determine the predictive factors of chronic glomerulonephritis in pediatric patients with PSAGN.

METHODS

This study was an analytical observational study with retrospective cohort design. The accessible population was children within the age of 2-18 years old who were admitted with PSAGN between January 2015 and December 2020 in Dr. Sardjito General Hospital Yogyakarta. All anonymized patient data were evaluated for demographic variables, clinical features, laboratory profiles and outcome. Multivariate analysis was performed with multivariate logistic regression method.

RESULTS

A total of 124 patients with PSAGN were obtained from medical record data. There were 65 patients (52.4%) with chronic glomerulonephritis. Bivariate analysis was performed on assumed predictive factors with the results indicating massive proteinuria with hypoalbuminemia (OR 1.670, 95%CI 1.199-2.326; p = 0.003), oliguria (OR 1.517, 95%CI 1.101-2.089; p = 0.028) and macroscopic hematuria (OR 1.647, 95%CI:1.061-2.555; p = 0.013) were significantly higher in the PSAGN group with chronic glomerulonephritis compared to those without. Results of the multivariate logistic regression analysis showed massive proteinuria with hypoalbuminemia (OR 2.896, 95%CI 1.177-7.123, p = 0.021) and macroscopic hematuria (OR 2.457, 95%CI ,1.018-5.933, p = 0.046) would highly predict chronic glomerulonephritis in subjects with PSAGN.

CONCLUSION

We concluded that massive proteinuria with hypoalbuminemia and macroscopic hematuria are the predictive factors which highly predict chronic glomerulonephritis in PSAGN.

Infection-Related Glomerulonephritis in Children and Adults

Infection-related glomerulonephritis is an immunologically mediated glomerular injury after an infection. Glomerulonephritis may occur with the infection or after a variable latent period. Poststreptococcal glomerulonephritis (PSGN) is the prototype of infection-related glomerulonephritis. The streptococcal antigens, nephritis-associated plasmin-like receptor and streptococcal exotoxin B, have emerged as major players in the pathogenesis of PSGN. Although PSGN is the most common infection-related glomerulonephritis in children, in adults, glomerulonephritis is secondary to bacteria such as staphylococci, viruses such as hepatitis C, and human immunodeficiency virus, and, rarely, parasitic infections. Supportive therapy is the mainstay of treatment in most infection-related glomerulonephritis. Treatment of the underlying infection with specific antibiotics and antiviral medications is indicated in some infections. Parasitic infections, although rare, may be associated with significant morbidity. Poststreptococcal glomerulonephritis is a self-limiting condition with a good prognosis. However, bacterial, viral, and parasitic infections may be associated with significant morbidity and long-term consequences. Epidemiologic studies are required to assess the global burden of infection-related glomerulonephritis. A better understanding of the pathogenesis of infection-related glomerulonephritis may unravel more treatment options and preventive strategies.

Management and outcomes of acute post-streptococcal glomerulonephritis in children

Acute post-streptococcal glomerulonephritis (APSGN) is the major cause of acute glomerulonephritis among children, especially in low- and middle-income countries. APSGN commonly occurs following pharyngitis due to the activation of antibodies and complements proteins against streptococcal antigens through the immune-complex-mediated mechanism. APSGN can be presented as acute nephritic syndrome, nephrotic syndrome, and rapidly progressive glomerulonephritis, or it may be subclinical. The management of APSGN is mainly supportive in nature with fluid restriction, anti-hypertensives, diuretics, and renal replacement therapy with dialysis, when necessary, as the disease is self-limiting. Congestive heart failure, pulmonary edema, and severe hypertension-induced encephalopathy might occur during the acute phase of APSGN due to hypervolemia. APSGN generally has a favorable prognosis with only a small percentage of patients with persistent urinary abnormalities, persistent hypertension, and chronic kidney disease after the acute episode of APSGN. Decreased complement levels, increased C-reactive protein, and hypoalbuminemia are associated with disease severity. Crescent formations on renal biopsy and renal insufficiency on presentation may be the predictors of disease severity and poor outcomes in APSGN in children.

Standardization of Epidemiological Surveillance of Acute Poststreptococcal Glomerulonephritis

Acute poststreptococcal glomerulonephritis (APSGN) is an immune complex-induced glomerulonephritis that develops as a sequela of streptococcal infections. This article provides guidelines for the surveillance of APSGN due to group A Streptococcus (Strep A). The primary objectives of APSGN surveillance are to monitor trends in age- and sex-specific incidence, describe the demographic and clinical characteristics of patients with APSGN, document accompanying risk factors, then monitor trends in frequency of complications, illness duration, hospitalization rates, and mortality.

This document provides surveillance case definitions for APSGN, including clinical and subclinical APSGN based on clinical and laboratory evidence. It also details case classifications that can be used to differentiate between confirmed and probable cases, and it discusses the current investigations used to provide evidence of antecedent Strep A infection.

The type of surveillance recommended depends on the burden of APSGN in the community and the objectives of surveillance. Strategies for minimal surveillance and enhanced surveillance of APSGN are provided. Furthermore, a discussion covers the surveillance population and additional APSGN-specific surveillance considerations such as contact testing, active follow up of cases and contacts, frequency of reporting, surveillance visits, period of surveillance, and community engagement. Finally, the document presents core data elements to be collected on case report forms, along with guidance for documenting the course and severity of APSGN.

Twenty-year Follow-up of Patients With Epidemic Glomerulonephritis due to Streptococcus zooepidemicus in Brazil

Introduction

Post-streptococcal glomerulonephritis (PSGN) has a good prognosis in children, but few studies have evaluated the long-term renal outcomes in adults with PSGN.

Methods

In a follow-up study, 47 predominantly adult patients with PSGN due to group C Streptococcus zooepidemicus were reassessed 20 years after an outbreak in Nova Serrana, Brazil. We evaluated clinical characteristics, renal outcomes, and the trajectory of the estimated glomerular filtration rate (eGFR) by the creatinine-based chronic kidney disease-epidemiology collaboration equation from 5 follow-up assessments. Logistic regression and mixed-effects regression were used in the analysis.

Results

After 20 years, the participants’ mean age was 56.6±15.1 years. Thirty-four (72%) patients had hypertension, 21 (44.7%) had eGFR <60 ml/min per 1.73 m², 8 of 43 (18.6%) had urine protein-to-creatinine ratio >150 mg/g, and 25 (53%) had CKD (low eGFR and/or increased proteinuria). Increasing age was associated with CKD (odds ratio: 1.07; 95% confidence interval [CI]: 1.02–1.13; P = 0.011) in multivariate analysis. The mean eGFR decline in the last 11 years of follow-up was −3.2 ml/min per 1.73 m² per year (95% CI: −3.7 to −2.7). Older age at baseline (coefficient −1.05 ml/min per 1.73 m² per year; 95% CI −1.28 to −0.81; P < 0.001), and hypertension 5 years after the outbreak (coefficient −7.78 ml/min/1.73 m²; 95% CI −14.67 to −0.78; P = 0.027) were associated with lower eGFR during the whole study period.

Conclusion

There was a marked worsening of renal function and a high prevalence of CKD and hypertension after 20 years of PSGN outbreak. Long-term follow-up is warranted after PSGN, especially among older patients.

IgA-dominant infection-associated glomerulonephritis in the pediatric population

BACKGROUND

IgA-dominant infection-associated glomerulonephritis is well-documented in adults but has not been studied in depth in children. We assessed the incidence of pediatric IgA-dominant infection-associated glomerulonephritis and clinical and kidney biopsy findings.

METHODS

Pediatric native kidney biopsies over a 10-year period with IgA dominance, strong C3, and findings indicative of infection-associated etiology were identified.

RESULTS

We identified 9 cases of IgA-dominant infection-associated glomerulonephritis, 0.8% of pediatric native kidney biopsies. Seven patients presented with elevated creatinine. All had hematuria and proteinuria. Eight patients had clinical evidence of infection: one each with central port infection by methicillin-sensitive Staphylococcus aureus, recurrent streptococcal pharyngitis and recent otitis media, streptococcal pharyngitis demonstrated 8 months after biopsy, suspected streptococcal scalded skin syndrome, and viral gastroenteritis, and three with serologic evidence of Streptococcal infection but no identified site of infection. All but one patient experienced short-term normalization of creatinine and resolution of proteinuria, though two eventually progressed to kidney failure: one 3 years later due to progressive disease and one 11 years later due to focal segmental glomerulosclerosis without concurrent immune deposits.

CONCLUSIONS

Pediatric IgA-dominant infection-associated glomerulonephritis is rare, and generally has a favorable prognosis, contrasting that seen in adults with severe comorbidities. A higher resolution version of the Graphical abstract is available as Supplementary.

Association of Built Environmental Features with Rates of Infectious Diseases in Remote Indigenous Communities in the Northern Territory, Australia

The health of Indigenous Australians is far poorer than non-Indigenous Australians, including an excess burden of infectious diseases. The health effect of built environmental (BE) features on Indigenous communities receives little attention. This study’s objective was to determine associations between BE features and infectious disease incidence rates in remote Indigenous communities in the Northern Territory (NT), Australia. Remote Indigenous communities (n = 110) were spatially joined to 93 Indigenous Locations (ILOC). Outcomes data were extracted (NT Notifiable Diseases System) and expressed as ILOC-specific incidence rates. Counts of buildings were extracted from community asset maps and grouped by function. Age-adjusted infectious disease rates were dichotomised, and bivariate binomial regression used to determine the relationships between BE variables and infectious disease. Infrastructure Shelter BE features were universally associated with significantly elevated disease outcomes (relative risk 1.67 to 2.03). Significant associations were observed for Services, Arena, Community, Childcare, Oval, and Sports and recreation BE features. BE groupings associated with disease outcomes were those with communal and/or social design intent or use. Comparable BE groupings without this intent or use did not associate with disease outcomes. While discouraging use of communal BE features during infectious disease outbreaks is a conceptually valid countermeasure, communal activities have additional health benefits themselves, and infectious disease transmission could instead be reduced through repairs to infrastructure, and more infrastructure. This is the first study to examine these associations simultaneously in more than a handful of remote Indigenous communities to illustrate community-level rather than aggregated population-level associations.

Protocol for the systematic review of the epidemiology of superficial Streptococcal A infections (skin and throat) in Australia

OBJECTIVE

We have produced a protocol for the comprehensive systematic review of the current literature around superficial group A Streptococcal infections in Australia.

METHODS

MEDLINE, Scopus, EMBASE, Web of Science, Global Health, Cochrane, CINAHL databases and the gray literature will be methodically and thoroughly searched for studies relating to the epidemiology of superficial group A Streptococcal infections between the years 1970 and 2019. Data will be extracted to present in the follow up systematic review.

CONCLUSION

A rigorous and well-organised search of the current literature will be performed to determine the current and evolving epidemiology of superficial group A Streptococcal infections in Australia.

Racial differences of early vascular aging in children and adolescents

The prevalence of non-communicable disease (NCDs) is rising globally, with a large burden recorded in sub-Saharan countries and populations of black race/ethnicity. Accelerated vascular deterioration, otherwise known as early vascular aging (EVA), is the underlying factor for highly prevalent NCDs such as hypertension. The etiology of EVA is multifactorial with a central component being arterial stiffness with subsequent development of hypertension and cardiovascular complications. Although arterial stiffness develops with increasing age, many children and adolescents are subjected to the premature development of arterial stiffness, due to genetic or epigenetic predispositions, lifestyle and behavioral risk factors, and early life programming. Race/ethnic differences in pediatric populations have also been reported with higher aortic stiffness in black (African American) compared with age-matched white (European American) counterparts independent of blood pressure, body mass index, or socioeconomic status. With known evidence of race/ethnic differences in EVA, the pathophysiological mechanisms underlying graded differences in the programming of EVA are still sparse and rarely explored. This educational review aims to address the early life determinants of EVA in children and adolescents with a particular focus on racial or ethnic differences.

Approach to Persistent Microscopic Hematuria in Children

Persistent isolated microscopic hematuria is relatively common in pediatric practice, affecting around 0.25% of children. Isolated microscopic hematuria can be caused by a myriad of potentially benign or serious causes, including urologic issues; kidney stones; glomerular diseases, including disorders of the glomerular basement membrane; hematologic abnormalities; and others. The challenge for the pediatrician or pediatric nephrologist is to distinguish children with potentially progressive forms of kidney disease versus other causes while minimizing cost and inconvenience for the child and family. This manuscript will review the multiple potential causes of microscopic hematuria and provide a framework for the initial evaluation and monitoring of such patients.

Estimating the global burden of scabies: what else do we need?

Scabies is one of the most common disorders identified in any estimate of global skin disease prevalence. Furthermore, quantifying its impact on individuals and societies has been problematic. There has been a lack of clear case definitions and laboratory tests. There have been few epidemiological studies, particularly those focusing on low-income countries, variation in prevalence within high-income countries, or estimates of the effect of scabies on health beyond the skin, such as renal disease or mental wellbeing. Economic studies are also lacking. However, the new strategy of integrating surveillance for skin Neglected Tropical Diseases may well produce advancements on these issues, in addition to providing an overarching structure for health improvement and disease control.

Post-streptococcal glomerulonephritis: Some reduction in a disease of disparities

AIM

A retrospective Auckland-wide (total population approximately 1.4 million) study of hospital admissions from 2007 to 2015 was conducted to assess trends in admissions for acute post-streptococcal glomerulonephritis (APSGN) in children aged 0-14 years.

METHODS

International Statistical Classification of Diseases (ICD10) discharge codes were used to identify potential cases of APSGN, and electronic clinical records and laboratory data were compared with established case definitions for definite or probable APSGN.

RESULTS

A total of 430 cases of APSGN were identified (definite n = 337, probable n = 93), with a mean annual incidence of 15.2/100 000 (95% confidence interval (CI) 14.9-15.6). Incidence (0-14 years) was 17 times higher in Pacific peoples (50.2/100 000, 95% CI 48.6-51.8) and almost 7 times higher in Māori (19.6/100 000, 95% CI 18.6-20.7) than European/other populations (2.9/100 000, 95% CI 2.7-3.1). Multivariate analysis found ethnicity, deprivation, male gender, age (peak 3-8 years) and season (summer/autumn) to be associated with admission risk. Admission rates showed a significant change of -9.0% (95% CI -10.4, 7.4%) per year, with 2011 being an exception. Low C3 complement, hypertension, elevated streptococcal titres, oedema and heavy proteinuria were present in 94, 65, 67, 52 and 49% of cases, respectively. Relying on ICD10 codes without further review of clinical notes would result in an overcount of cases by 25%.

CONCLUSIONS

There is severe disparity in APSGN admission rates, with a disproportionate burden of disease for Pacific and Māori children and those living in deprived circumstances. Rates trended downward from 2007 to 2015.

Evaluation of safety and immunogenicity of a group A streptococcus vaccine candidate (MJ8VAX) in a randomized clinical trial

BACKGROUND

Group A streptococcus (GAS) is a serious human pathogen that affects people of different ages and socio-economic levels. Although vaccination is potentially one of the most effective methods to control GAS infection and its sequelae, few prototype vaccines have been investigated in humans. In this study, we report the safety and immunogenicity of a novel acetylated peptide-protein conjugate vaccine candidate MJ8VAX (J8-DT), when delivered intramuscularly to healthy adults.

METHODS

A randomized, double-blinded, controlled Phase I clinical trial was conducted in 10 healthy adult participants. Participants were randomized 4:1 to receive the vaccine candidate (N = 8) or placebo (N = 2). A single dose of the vaccine candidate (MJ8VAX), contained 50 μg of peptide conjugate (J8-DT) adsorbed onto aluminium hydroxide and re-suspended in PBS in a total volume of 0.5 mL. Safety of the vaccine candidate was assessed by monitoring local and systemic adverse reactions following intramuscular administration. The immunogenicity of the vaccine was assessed by measuring the levels of peptide (anti-J8) and toxoid carrier (anti-DT)-specific antibodies in serum samples.

RESULTS

No serious adverse events were reported over 12 months of study. A total of 13 adverse events (AEs) were recorded, two of which were assessed to be associated with the vaccine. Both were mild in severity. No local reactogenicity was recorded in any of the participants. MJ8VAX was shown to be immunogenic, with increase in vaccine-specific antibodies in the participants who received the vaccine. The maximum level of vaccine-specific antibodies was detected at 28 days post immunization. The level of these antibodies decreased with time during follow-up. Participants who received the vaccine also had a corresponding increase in anti-DT serum antibodies.

CONCLUSIONS

Intramuscular administration of MJ8VAX was demonstrated to be safe and immunogenic. The presence of DT in the vaccine formulation resulted in a boost in the level of anti-DT antibodies.

TRIAL REGISTRATION

ACTRN12613000030774.

Analysis of clinical presentation, pathological spectra, treatment and outcomes of biopsy-proven acute postinfectious glomerulonephritis in adult indigenous people of the Northern Territory of Australia

AIM

Acute postinfectious glomerulonephritis is common in indigenous communities in the Northern Territory, Australia. It is a major risk factor for the high prevalence of chronic kidney disease. We aimed to analyse the clinical presentation, pathological spectra, treatment and outcomes of biopsy-proven acute postinfectious glomerulonephritis in the Northern Territory.

METHODS

We performed a retrospective cohort analysis of all adult patients (≥18 years) who were diagnosed with acute postinfectious glomerulonephritis on native renal biopsies from 01/01/2004 to 31/05/2014. The outcome measure was end-stage renal disease requiring long-term dialysis.

RESULTS

Forty-three of 340 patients who had renal biopsies had acute postinfectious glomerulonephritis. Most were Aboriginals (88.4%). They had co-morbidities; diabetes mellitus (60.5%), hypertension (60.5%) and smoking (56.4%). Forty-nine per cent had multiple pathologies on biopsy. Predominant histological pattern was diffuse proliferative glomerulonephritis (72%). Main sites of infections were skin (47.6%) and upper respiratory tract infection (26.2%) with streptococcus and staphylococcus as predominant organisms. Fifty per cent of patients developed end-stage renal disease. On multivariable logistic regression analysis, those on dialysis had higher baseline creatinine (P = 0.003), higher albumin/creatinine ratio at presentation (P = 0.023), higher serum creatinine at presentation (P = 0.02) and lower estimated glomerular filtration rate at presentation (P = 0.012).

CONCLUSION

Overall, most patients had pre-existing pathology with superimposed acute postinfectious glomerulonephritis that led to poor outcomes in our cohort.

Kidney Disease Among Registered Métis Citizens of Ontario: A Population-Based Cohort Study

Background:

Indigenous peoples in Canada have higher rates of kidney disease than non-Indigenous Canadians. However, little is known about the risk of kidney disease specifically in the Métis population in Canada.

Objective:

To compare the prevalence of chronic kidney disease and incidence of acute kidney injury and end-stage kidney disease among registered Métis citizens in Ontario and a matched sample from the general Ontario population.

Design:

Population-based, retrospective cohort study using data from the Métis Nation of Ontario’s Citizenship Registry and administrative databases.

Setting:

Ontario, Canada; 2003-2013.

Patients:

Ontario residents ≥18 years.

Measurements:

Prevalence of chronic kidney disease and incidence of acute kidney injury and end-stage kidney disease. Secondary outcomes among patients hospitalized with acute kidney injury included non-recovery of kidney function and mortality within 1 year of discharge.

Methods:

Database codes and laboratory values were used to determine study outcomes. Métis citizens were matched (1:4) to Ontario residents on age, sex, and area of residence. The analysis included 12 229 registered Métis citizens and 48 916 adults from the general population.

Results:

We found the prevalence of chronic kidney disease was slightly higher among Métis citizens compared with the general population (3.1% vs 2.6%, P = 0.002). The incidence of acute kidney injury was 1.2 per 1000 person-years in both Métis citizens and the general population (P = 0.54). Of those hospitalized with acute kidney injury, outcomes were similar among Métis citizens and the general population except 1-year mortality, which was higher for Métis citizens (24.5% vs 15.3%, P = 0.03). The incidence of end-stage kidney disease did not differ between groups (<3.0 per 10 000 person-years, P = 0.73).

Limitations:

The Métis Nation of Ontario Citizenship Registry only captures about 20% of Métis people in Ontario. Administrative health care codes used to identify kidney disease are highly specific but have low sensitivity.

Conclusions:

Rates of kidney disease were similar or slightly higher for Métis citizens in Ontario compared with the matched general population.

Streptococcal Immunity Is Constrained by Lack of Immunological Memory following a Single Episode of Pyoderma

The immunobiology underlying the slow acquisition of skin immunity to group A streptococci (GAS), is not understood, but attributed to specific virulence factors impeding innate immunity and significant antigenic diversity of the type-specific M-protein, hindering acquired immunity. We used a number of epidemiologically distinct GAS strains to model the development of acquired immunity. We show that infection leads to antibody responses to the serotype-specific determinants on the M-protein and profound protective immunity; however, memory B cells do not develop and immunity is rapidly lost. Furthermore, antibodies do not develop to a conserved M-protein epitope that is able to induce immunity following vaccination. However, if re-infected with the same strain within three weeks, enduring immunity and memory B-cells (MBCs) to type-specific epitopes do develop. Such MBCs can adoptively transfer protection to naïve recipients. Thus, highly protective M-protein-specific MBCs may never develop following a single episode of pyoderma, contributing to the slow acquisition of immunity and to streptococcal endemicity in at-risk populations.

GAS skin infections pose a significant health problem in the tropics. They are highly prevalent in developing countries as well as amongst the Indigenous populations of developed countries. In at-risk impoverished communities the epidemiology of GAS infections is very dynamic, leading to very high rates of streptococcal-associated serious pathology including rheumatic heart disease, glomerulonephritis and invasive GAS disease. Immunity to GAS takes over 20 years to develop and this has been attributed to sequence diversity of the type-specific surface M-protein. There are more than 250 different strains of GAS and it known that antibodies to the amino-terminal segment of the M-protein can kill organisms in a strain-specific manner in vitro. In the present study, using four different strains of GAS isolated from the skin lesions of Aboriginal patients in the Northern Territory of Australia, we make the discovery that skin infection does not induce long-lived type-specific immunity. However, following reinfection with the same strain memory B cells are generated and long-term strain-protective immunity then develops. The dependence on reinfection for the development of strain-specific immunity compounds with antigenic diversity of the M-protein and provides a rational explanation for the very slow acquisition of streptococcal immunity.

Familial aggregation of albuminuria and arterial hypertension in an Aboriginal Australian community and the contribution of variants in ACE and TP53

Background

Aboriginal Australians are at high risk of cardiovascular, metabolic and renal diseases, resulting in a marked reduction in life expectancy when compared to the rest of the Australian population. This is partly due to recognized environmental and lifestyle risk factors, but a contribution of genetic susceptibility is also likely.

Methods

Using results from a comprehensive survey of one community (N = 1350 examined individuals), we have tested for familial aggregation of plasma glucose, arterial blood pressure, albuminuria (measured as urinary albumin to creatinine ratio, UACR) and estimated glomerular filtration rate (eGFR), and quantified the contribution of variation at four candidate genes (ACE; TP53; ENOS3; MTHFR).

Results

In the subsample of 357 individuals with complete genotype and phenotype data we showed that both UACR (h² = 64%) and blood pressure (sBP h² = 29%, dBP, h² = 11%) were significantly heritable. The ACE insertion-deletion (P = 0.0009) and TP53 codon72 polymorphisms (P = 0.003) together contributed approximately 15% of the total heritability of UACR, with an effect of ACE genotype on BP also clearly evident.

Conclusions

While the effects of the ACE insertion-deletion on risk of renal disease (especially in the setting of diabetes) are well recognized, this is only the second study to implicate p53 genotype as a risk factor for albuminuria - the other being an earlier study we performed in a different Aboriginal community (McDonald et al., J Am Soc Nephrol 13: 677-83, 2002). We conclude that there are significant genetic contributions to the high prevalence of chronic diseases observed in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0396-2) contains supplementary material, which is available to authorized users.

Preclinical Study of Single-Dose Moxidectin, a New Oral Treatment for Scabies: Efficacy, Safety, and Pharmacokinetics Compared to Two-Dose Ivermectin in a Porcine Model

Background

Scabies is one of the commonest dermatological conditions globally; however it is a largely underexplored and truly neglected infectious disease. Foremost, improvement in the management of this public health burden is imperative. Current treatments with topical agents and/or oral ivermectin (IVM) are insufficient and drug resistance is emerging. Moxidectin (MOX), with more advantageous pharmacological profiles may be a promising alternative.

Methodology/Principal Findings

Using a porcine scabies model, 12 pigs were randomly assigned to receive orally either MOX (0.3 mg/kg once), IVM (0.2 mg/kg twice) or no treatment. We evaluated treatment efficacies by assessing mite count, clinical lesions, pruritus and ELISA-determined anti-S. scabiei IgG antibodies reductions. Plasma and skin pharmacokinetic profiles were determined. At day 14 post-treatment, all four MOX-treated but only two IVM-treated pigs were mite-free. MOX efficacy was 100% and remained unchanged until study-end (D47), compared to 62% (range 26–100%) for IVM, with one IVM-treated pig remaining infected until D47. Clinical scabies lesions, pruritus and anti-S. scabiei IgG antibodies had completely disappeared in all MOX-treated but only 75% of IVM-treated pigs. MOX persisted ~9 times longer than IVM in plasma and skin, thereby covering the mite’s entire life cycle and enabling long-lasting efficacy.

Conclusions/Significance

Our data demonstrate that oral single-dose MOX was more effective than two consecutive IVM-doses, supporting MOX as potential therapeutic approach for scabies.

Scabies caused by the Sarcoptes scabiei mite affects many people worldwide and has been recently recognized by the WHO as a truly neglected tropical disease. Currently available treatments are insufficient to overcome this insidious disease and its co-morbidities for example impetigo, rheumatic heart disease and post-streptococcal glomerulonephritis. Treatment management is a major issue, as problems with compliance as well as mite resistance to current drugs are reported. Data have accumulated indicating that moxidectin could be a genuine new candidate drug for sustainable scabies control. To provide proof of concept, we utilized an experimental scabies pig model that closely resembles the human route of scabies infection. We demonstrated that a single moxidectin dose, when compared with the currently recommended two-doses ivermectin treatment routine, achieved a better and faster acaricidal efficacy. Importantly, the skin half-life of moxidectin is longer, potentially covering the entire mite life cycle. Our baseline data demonstrate in principle the potential and feasibility of moxidectin treatment for scabies, thereby enabling the move into larger high-powered efficacy and dose ranging studies in human populations. Moxidectin could indeed play a game-changing role in scabies control and has the potential to accelerate the steps towards elimination of this insidious disease.

Whole genome sequencing reveals extensive community-level transmission of group A Streptococcus in remote communities

Impetigo is common in remote Indigenous children of northern Australia, with the primary driver in this context being Streptococcus pyogenes [or group A Streptococcus (GAS)]. To reduce the high burden of impetigo, the transmission dynamics of GAS must be more clearly elucidated. We performed whole genome sequencing on 31 GAS isolates collected in a single community from children in 11 households with ⩾2 GAS-infected children. We aimed to determine whether transmission was occurring principally within households or across the community. The 31 isolates were represented by nine multilocus sequence types and isolates within each sequence type differed from one another by only 0-3 single nucleotide polymorphisms. There was evidence of extensive transmission both within households and across the community. Our findings suggest that strategies to reduce the burden of impetigo in this setting will need to extend beyond individual households, and incorporate multi-faceted, community-wide approaches.

Progression of Kidney Disease in Indigenous Australians: The eGFR Follow-up Study

BACKGROUND AND OBJECTIVES

Indigenous Australians experience a heavy burden of CKD. To address this burden, the eGFR Follow-Up Study recruited and followed an Indigenous Australian cohort from regions of Australia with the greatest ESRD burden. We sought to better understand factors contributing to the progression of kidney disease. Specific objectives were to assess rates of progression of eGFR in Indigenous Australians with and without CKD and identify factors associated with a decline in eGFR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This observational longitudinal study of Indigenous Australian adults was conducted in >20 sites. The baseline cohort was recruited from community and primary care clinic sites across five strata of health, diabetes status, and kidney function. Participants were then invited to follow up at 2-4 years; if unavailable, vital status, progression to RRT, and serum creatinine were obtained from medical records. Primary outcomes were annual eGFR change and combined renal outcome (first of ≥30% eGFR decline with follow-up eGFR<60 ml/min per 1.73 m(2), progression to RRT, or renal death).

RESULTS

Participants (n=550) were followed for a median of 3.0 years. Baseline and follow-up eGFR (geometric mean [95% confidence interval], 83.9 (80.7 to 87.3) and 70.1 (65.9 to 74.5) ml/min per 1.73 m(2), respectively. Overall mean annual eGFR change was -3.1 (-3.6 to -2.5) ml/min per 1.73 m(2). Stratified by baseline eGFR (≥90, 60-89, <60 ml/min per 1.73 m(2)), annual eGFR changes were -3.0 (-3.6 to -2.4), -1.9 (-3.3 to -0.5), and -5.0 (-6.5 to -3.6) ml/min per 1.73 m(2). Across baseline eGFR categories, annual eGFR decline was greatest among adults with baseline albumin-to-creatinine ratio (ACR) >265 mg/g (30 mg/mmol). Baseline determinants of the combined renal outcome (experienced by 66 participants) were higher urine ACR, diabetes, lower measured GFR, and higher C-reactive protein.

CONCLUSIONS

The observed eGFR decline was three times higher than described in nonindigenous populations. ACR was confirmed as a powerful predictor for eGFR decline across diverse geographic regions.

Antibodies to group A streptococcal virulence factors, SIC and DRS, increase predilection to GAS pyoderma

BACKGROUND

Streptococcus pyogenes (group A streptococcus; GAS) is an etiological agent for pharyngitis, pyoderma, and invasive infections in humans. Pharyngitis and pyoderma may lead to serious immune sequelae such as rheumatic heart disease and post-streptococcal glomerulonephritis (PSGN). Streptococcal Inhibitor of Complement (SIC) and its orthologue, distantly related to SIC (DRS), are virulence factors expressed by only four of more than 100 M types of GAS. These four types (M1, M57, M12 and M55) are among the M types, which are associated with PSGN. In several populations PSGN has been shown to be a risk factor for chronic kidney disease (CKD) and end-stage renal disease (ESRD). Previous studies showed SIC or DRS antibody-prevalence was associated with PSGN, and seroprevalence of SIC antibodies is significantly high among CKD and ESRD patients in Mumbai.

METHODS

Streptococcal isolates recovered from GAS pyoderma cases were typed. Seropositivity for SIC and DRS antibodies in subjects with pyoderma, PSGN pediatric cases, age matched healthy controls and non-GAS pyoderma cases were determined.

RESULTS

We confirm in this study an association between seroprevalence to SIC and DRS antibodies, and PSGN in Mumbai population despite low point prevalence of M1, M12, M55 and M57. In addition we extended the study to GAS-pyoderma and non-GAS pyoderma cases. To our surprise, we found a positive association between the seroprevalence to SIC and DRS antibodies, and GAS-pyoderma owing to infection with diverse M types. The mechanism of increased predisposition to pyoderma owing to infection by diverse GAS among SIC or DRS antibody-positive population is not clear. Nonetheless, our findings could be explained by a phenomenon akin to antibody-dependent enhancement (ADE).

CONCLUSIONS

This is the first report showing a small number of GAS M types conferring predisposition to pyoderma by diverse types. Implications of this ADE-like phenomenon are discussed in the light of evolutionary advantage to GAS, vaccine design and control of renal diseases.

Disease manifestations and pathogenic mechanisms of Group A Streptococcus

Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.

Prospective population-based study on the burden of disease from post-streptococcal glomerulonephritis of hospitalised children in New Zealand: epidemiology, clinical features and complications

AIM

A nationwide 24-month study was conducted (2007-2009), via the New Zealand Paediatric Surveillance Unit to define epidemiology and clinical features of acute poststreptococcal glomerulonephritis (APSGN) in children hospitalised with the illness.

METHODS

Paediatricians (n = 215) were requested to report new hospitalised cases fulfilling a case definition of definite (haematuria with low C3 and high streptococcal titres or biopsy proven APSGN) or probable (haematuria with low C3 or high streptococcal titres).

RESULTS

A total of 176 cases were identified (definite: n = 138, probable: n = 38) with 63% residing in the Auckland metropolitan region. Sixty-seven percent were in the most deprived quintile. Annual incidence (0-14 years) was 9.7/100,000 (Pacific 45.5, Maori 15.7, European/other 2.6 and Asian 2.1/100,000). Annual incidence was highest in the South Auckland Metropolitan region (31/100,000), Central Auckland 14.9, West/North Auckland metropolitan region 5.9 and for the remainder of New Zealand 5.5/100,000. Age-specific incidence was highest in age 5-9 years (15.1/100,000). Reduced serum complement C3, gross haematuria, hypertension, impairment of renal function and heavy proteinuria were present in 93%, 87%, 72%, 67% and 44% of patients, respectively. Severe hypertension was closely associated with either symptoms of an acute encephalopathy or congestive heart failure.

CONCLUSIONS

New Zealand children carry a significant disease burden of hospitalised APSGN with socio-economically deprived; Pacific and Maori children are being over-represented. Significant short-term complications were observed in hospitalised children with APSGN. Persistently very low rates in European/other suggest a preventable disease.

Extensive diversity of Streptococcus pyogenes in a remote human population reflects global-scale transmission rather than localised diversification

The Indigenous population of the Northern Territory of Australia (NT) suffers from a very high burden of Streptococcus pyogenes disease, including cardiac and renal sequelae. The aim of this study was to determine if S. pyogenes isolated from this population represent NT endemic strains, or conversely reflect strains with global distribution. emm sequence typing data were used to select 460 S. pyogenes isolates representing NT S. pyogenes diversity from 1987–2008. These isolates were genotyped using either multilocus sequence typing (MLST) or a high resolution melting-based MLST surrogate (Minim typing). These data were combined with MLST data from other studies on NT S. pyogenes to yield a set of 731 MLST or Minim typed isolates for analysis. goeBURST analysis of MLST allelic profiles and neighbour-joining trees of the MLST allele sequences revealed that a large proportion of the known global S. pyogenes MLST-defined diversity has now been found in the NT. Specifically, fully sequence typed NT isolates encompass 19% of known S. pyogenes STs and 43% of known S. pyogenes MLST alleles. These analyses provided no evidence for major NT-endemic strains, with many STs and MLST alleles shared between the NT and the rest of the world. The relationship between the number of known Minim types, and the probability that a Minim type identified in a calendar year would be novel was determined. This revealed that Minim types typically persist in the NT for >1 year, and indicate that the majority of NT Minim types have been identified. This study revealed that many diverse S. pyogenes strains exhibit global scale mobility that extends to isolated populations. The burden of S. pyogenes disease in the NT is unlikely to be due to the nature of NT S. pyogenes strains, but is rather a function of social and living conditions.

Impact of scabies in resource-poor communities

PURPOSE OF REVIEW

Features of endemic scabies are specific in resource-poor and underprivileged communities, with implications for control measures on the community level. In this review, these special aspects are addressed.

RECENT FINDINGS

Scabies is endemic in many resource-poor communities, with a prevalence of 20% and higher. Transmission is influenced by social attitudes, migration, access to healthcare services, housing conditions, hygiene conditions, and crowding. Endemic scabies occurs with severe infestations, complications, and sequels, mainly in children. Sleep loss as a result of scabies-related itching is common. Complications include secondary infections by group A streptococci and acute poststreptococcal glomerulonephritis. Shame, restriction of leisure activities, and stigmatization are common. Treatment of scabies includes a variety of topical compounds, but control on the community level is not an easy task. As ivermectin kills a variety of other parasites, this oral drug is increasingly used for mass treatment. Intervention should address socioemotional aspects using an integrated approach with professionals from different areas, and the community.

SUMMARY

Scabies is a neglected disease and needs to be perceived as an important public health problem causing morbidity in many resource-poor communities. Future work on epidemiology, clinical aspects, transmission dynamics, socioeconomic aspects, and sustainable control in resource-poor communities is needed.

The elimination of scabies: a task for our generation

Scabies prevalence remains unacceptably high in many regions throughout the world. Infestation with scabies significantly impacts quality of life and is linked to pyoderma and consequently to severe long-term sequelae such as post-streptococcal glomerulonephritis. In the past, control programs using topical treatments have met with poor compliance; however, the highly effective oral agent ivermectin may offer a new paradigm in scabies management. Problems still exist with insensitive diagnostic tests, questions concerning mite reservoirs, and restrictions on who can receive ivermectin. Despite these difficulties, the elimination of scabies in communities worst affected may soon be possible.

Seroprevalence of Streptococcal Inhibitor of Complement (SIC) suggests association of streptococcal infection with chronic kidney disease

BACKGROUND

Group A streptococcus (GAS) is an etiological agent for the immune mediated sequela post streptococcal glomerulonephritis (PSGN). In some populations PSGN is recognized as a risk factor for chronic kidney disease (CKD) and end-stage renal disease (ESRD). It was found that a significantly greater proportion of subjects with past history of PSGN than without the history exhibited seroreactions to streptococcal antigens called streptococcal inhibitor of complement (SIC) and to distantly related SIC (DRS). These antigens are expressed by major PSGN-associated GAS types. We therefore predicted that in populations such as India, which is endemic for streptococcal diseases and which has high prevalence of CKD and ESRD, greater proportions of CKD and ESRD patients exhibit seroreaction to SIC and DRS than healthy controls.

METHODS

To test this we conducted a SIC and DRS seroprevalence study in subjects from Mumbai area. We recruited 100 CKD, 70 ESRD and 70 healthy individuals.

RESULTS

Nineteen and 35.7% of CKD and ESRD subjects respectively were SIC antibody-positive, whereas only 7% of healthy cohort was seropositive to SIC. Furthermore, significantly greater proportion of the ESRD patients than the CKD patients is seropositive to SIC (p=0.02; odds ratio 2.37). No association was found between the renal diseases and DRS-antibody-positivity.

CONCLUSIONS

Past infection with SIC-positive GAS is a risk factor for CKD and ESRD in Mumbai population. Furthermore, SIC seropositivity is predictive of poor prognosis of CKD patients.

Scabies increased the risk of chronic kidney disease: a 5-year follow-up study

BACKGROUND

The most documented complication of scabies has been reported to be infection by group A streptococci, which has in turn been suggested to contribute to the development of glomerulonephritis.

OBJECTIVE

This study aimed to investigate the risk of chronic kidney disease (CKD) subsequent to scabies utilizing a population-based dataset in Taiwan.

METHODS

This retrospective matched-cohort study included 5071 subjects with scabies and 25 355 randomly selected comparison subjects. We individually tracked each subject for a 5-year period to identify those who subsequently received a diagnosis of CKD during the follow-up period. Stratified Cox proportional hazards regressions were performed to compute the hazard ratio (HR) of CKD during the 5-year follow-up period.

RESULTS

The incidence rate of CKD during the 5-year follow-up period was 9.66 (8.51-10.93) per 1,000 person-years and 6.24 (5.82-6.69) per 1000 person-years for subjects with and without scabies respectively. The HR for CKD during the 5-year follow-up period for subjects with scabies was 1.34 (95% CI = 1.15-1.56) that of comparison subjects after adjusting for monthly income, hypertension, diabetes, obesity, stroke, coronary heart disease, chronic obstructive pulmonary disease, tobacco use disorder, hyperlipidemia and alcohol abuse during the 5-year follow-up period. Male subjects with scabies were 1.40 (95% CI = 1.14-1.71) times more likely than comparison subjects to suffer from subsequent CKD, and female study subjects were 1.27 (95% CI = 1.05-1.61) times more likely.

CONCLUSIONS

We concluded that there was an increased risk for CKD among patients suffering from scabies.

Scabies in the developing world--its prevalence, complications, and management

Scabies remains one of the commonest of skin diseases seen in developing countries. Although its distribution is subject to a cycle of infection, with peaks and troughs of disease prevalence, this periodicity is often less obvious in poor communities. Scabies is a condition that affects families, particularly the most vulnerable; it also has the greatest impact on young children. Largely through the association with secondary bacterial infection caused by group A streptococci and Staphylococcus aureus, the burden of disease is compounded by nephritis, rheumatic fever and sepsis in developing countries. However, with a few notable exceptions, it remains largely neglected as an important public health problem. The purpose of this review is to provide an update on the current position of scabies with regard to its complications and control in resource-poor countries.

[Acute postinfectious glomerulonephritis]

Acute postinfectious glomerulonephritis are defined by an acute nonsuppurative inflammatory insult predominantly glomerular. Its current incidence is uncertain because of the frequency of subclinical forms. The most common infectious agent involved is beta hemolytic streptococcus group A. Acute postinfectious glomerulonephritis is uncommon in adults, and its incidence is progressively declining in developed countries. Humoral immunity plays a key role in the pathogenesis of kidney damage. Complement activation by the alternative pathway is the dominant mechanism, but a third way (lectin pathway) has been recently identified. The classic clinical presentation is sudden onset of acute nephritic syndrome after a free interval from a streptococcal infection. Treatment is essentially symptomatic and prevention is possible through improved hygiene and early treatment of infections.

Post-streptococcal glomerulonephritis is a strong risk factor for chronic kidney disease in later life

Although unusual in western countries and in Australia in general, post-streptococcal glomerulonephritis (PSGN) is still common in Australian Aboriginal children living in remote communities. Here, we evaluated whether episodes of acute PSGN increased the risk for chronic kidney disease in later life in 1519 residents of a remote Aboriginal community (85% of those age eligible), with high rates of renal and cardiovascular disease, who participated in a health screen over a 3-year period. Of these, 200 had had at least one episode of PSGN, with 27 having had multiple episodes, usually in childhood. High levels of albuminuria (albumin/creatinine ratio) with increasing age were confirmed. All PSGN episodes were associated with group A streptococcal skin infections, often related to scabies. In both genders, aged 10-39 years at screening, about one in five had such a history. Among them, PSGN (5 years or more earlier) was significantly associated with higher levels of albuminuria than those without. In women, aged 30-39 years, a history of PSGN was associated with a significantly higher frequency of estimated glomerular filtration rates <60 ml/min. The adjusted odds ratios for an albumin/creatinine ratio over 34 g/mol (overt albuminuria) in males and females with a history of PSGN were 4.6 and 3.1, respectively, compared with those without a history. Thus, PSGN contributes to the very serious burden of chronic kidney disease in this community. Rigorous strategies to prevent scabies and Group A streptococcal infections will reduce this burden.

Group a streptococcal diseases and their global burden

Group A streptococcus (GAS) or Streptococcus pyogenes has been recognised as an important human pathogen since early days of modern microbiology, and it remains among the top ten causes of mortality from an infectious disease. Clinical manifestations attributable to this organism are perhaps the most diverse of any single human pathogen. These encompass invasive GAS infections, with high mortality rates despite effective antimicrobials, toxin-mediated diseases including scarlet fever and streptococcal toxic shock syndrome, the autoimmune sequelae of rheumatic fever and glomerulonephritis with potential for long-term disability, and nuisance manifestations of superficial skin and pharyngeal infection, which continue to consume a sizable proportion of healthcare resources. Although an historical perspective indicates major overall reductions in GAS infection rates in the modern era, chiefly as a result of widespread improvements in socioeconomic circumstances, this pathogen remains as a leading infectious cause of global morbidity and mortality. More than 18 million people globally are estimated to suffer from serious GAS disease. This burden disproportionally affects least affluent populations, and is a major cause of illness and death among children and young adults, including pregnant women, in low-resource settings. We review GAS transmission characteristics and prevention strategies, historical and geographical trends and report on the estimated global burden disease attributable to GAS. The lack of systematic reporting makes accurate estimation of rates difficult. This highlights the need to support improved surveillance and epidemiological research in low-resource settings, in order to enable better assessment of national and global disease burdens, target control strategies appropriately and assess the success of control interventions.

Acute post-streptococcal glomerulonephritis in the Northern Territory of Australia: a review of 16 years data and comparison with the literature

Data relating to acute post-streptococcal glomerulonephritis (APSGN) from the notifiable diseases surveillance system in the Northern Territory of Australia was extracted and analyzed. Isolates of Streptococcus pyogenes from confirmed cases were emm sequence typed. From 1991 to July 2008, there were 415 confirmed cases and 23 probable cases of APSGN notified. Four hundred fifteen (94.7%) of these were Indigenous Australians and 428 (97.7%) were people living in remote or very remote locations. The median age of cases was 7 years (range 0-54). The incidence of confirmed cases was 12.5/100,000 person-years, with an incidence in Indigenous Australian children younger than 15 years of age of 94.3 cases/100,000 person-years. The overall rate ratio of confirmed cases in Indigenous Australians to non-Indigenous Australians was 53.6 (95% confidence interval 32.6-94.8). Outbreaks of disease across multiple communities occurred in 1995 (N = 68), 2000 (N = 55), and 2005 (N = 87 [confirmed cases]). Various emm types of S. pyogenes were isolated from cases of APSGN including some types not previously recognized to be nephritogenic. The widespread outbreak in 2005 was caused by emm55.0 S. pyogenes. Acute post-streptococcal glomerulonephritis continues to occur in remote Indigenous communities in Australia at rates comparable to or higher than those estimated in developing countries. Improvements in preventative and outbreak control strategies are needed.

Managing skin disease in resource-poor environments - the role of community-oriented training and control programs

Programs that have been devised to improve the lot of patients with skin disease, or disease presenting with skin signs and symptoms, in resource-poor regions have focused mainly on education and training or community-oriented control measures. However, both have in common an objective of managing disease at population level. Training has been delivered in different ways both by direct teaching for varying periods of time or by web-based and electronic communication; control measures have been less in evidence and there is a great need for more support from funding agencies. Despite this, there is now a growing number of successful initiatives in health improvement for skin conditions that cover many parts of the world. This report describes many of these schemes as an example of what can be done to help patients.

Acute reversible changes of brachial-ankle pulse wave velocity in children with acute poststreptococcal glomerulonephritis

Acute poststreptococcal glomerulonephritis (APSGN) is the most common form of postinfectious nephritis worldwide. The relationship between inflammation and arterial stiffness has been described elsewhere, but there have been no studies that have analyzed the association between arterial compliance and APSGN. The aim of this study is to assess brachial-ankle pulse wave velocity (baPWV) in pediatric patients with APSGN, and the value of baPWV in predicting the outcome. We evaluated 16 children diagnosed with APSGN, 11 children with acute pyelonephritis (APN), and 25 healthy individuals in our hospital. The baPWV of all candidates was measured. In addition, follow-up of the APSGN group was conducted for baPWV, blood pressure and biochemical parameters. Significantly increased baPWV was observed in the APSGN group at initial diagnosis (P<0.001), in comparison with the APN group and healthy controls. Of these, 13 patients received sequential measurement of baPWV. Overwhelmingly, baPWV was rapidly normalized in 11 patients, whereas 2 boys presented with persistently higher baPWV. During the follow-up period of 2-3 years, both had consistency of proteinuria, and consequently, they progressed to either chronic renal insufficiency or end-stage renal disease (ESRD). In conclusion, the results demonstrate that APSGN involves not only the kidney, but also the arteries outside the kidney. Acute arterial stiffness might persist in patients who do not recover, but develop chronic kidney disease (CKD).

Control strategies for endemic childhood scabies

Human scabies is a major global public health issue, with an estimated 300 million cases per year worldwide. Prevalence rates are particularly high in many third-world regions and within various indigenous communities in developed countries. Infestation with Sarcoptes Scabiei is associated with group-A streptococcal pyoderma which in turn predisposes to rheumatic fever, acute glomerulonephritis and their respective long-term sequelae: rheumatic heart disease and chronic renal insufficiency. The documented difficulties inherent in achieving scabies control within affected communities have motivated us to develop a network-dependent Monte-Carlo model of the scabies contagion, with the dual aims of gaining insight into its dynamics, and in determining the effects of various treatment strategies. Here we show that scabies burden is adversely affected by increases in average network degree, prominent network clustering, and by a person-to-person transmissibility of greater magnitude. We demonstrate that creating a community-specific model allows for the determination of an effective treatment protocol that can satisfy any pre-defined target prevalence. We find frequent low-density treatment protocols are inherently advantageous in comparison with infrequent mass screening and treatment regimes: prevalence rates are lower when compared with protocols that administer the same number of treatments over a given time interval less frequently, and frequent low-density treatment protocols have economic, practical and public acceptance advantages that may facilitate their long-term implementation. This work demonstrates the importance of stochasticity, community structure and the heterogeneity of individuals in influencing the dynamics of the human scabies contagion, and provides a practical method for investigating the outcomes of various intervention strategies.

The burden of kidney disease in indigenous children of Australia and New Zealand, epidemiology, antecedent factors and progression to chronic kidney disease

AIMS

To review and present the most important issues related to kidney disease in Aboriginal, Torres Strait Islander, Maori and Pacific Islander children from Australia and New Zealand.

METHODS

A review of medical literature about: 1. incidence of kidney disease in Indigenous children in Australia and New Zealand, especially where rates are different from the general populations, 2. factors in early life which increase risk for chronic kidney disease in adult life, and 3. early identification and primary and secondary interventions in childhood which may prevent chronic kidney disease in adults.

RESULTS

Kidney diseases, both acute and chronic are more common in Maori, Pacific Islander, Australian Aboriginal and Torres Strait Islander people. The reasons are multiple and include genetic, environmental and socio-economic factors. In childhood post streptococcal glomerulonephritis, haemolytic uraemic syndrome, renal stones and acute kidney injury all occur at higher frequency in at least some of the Indigenous populations. Chronic kidney disease CKD occurs more commonly, and at a younger age in Indigenous than non Indigenous people. Factors involved may include reduced nephron endowment at birth, and subsequent insults including nephritis, obesity, and early onset type 2 diabetes, as well as underlying socioeconomic and environmental determinants.

CONCLUSION

A lifecourse understanding allows one to conceptualise multiple risk factors and target interventions.

Hygiene improvement: essential to improving child health in remote Aboriginal communities

It is generally recognised that poor living conditions and poor hygiene underlie the high burden of infection experienced by Indigenous (Aboriginal and Torres Strait Islander) children living in remote communities. There has been little research on this topic. Taking an ecological approach, our study aimed to identify the key factors contributing to poor hygiene in one remote Aboriginal community and to determine appropriate approaches for improving hygiene and reducing the burden of infection among children. Key findings include that multifaceted interventions are required to ensure that household water and sanitation technology are functional, hygiene behaviour change is achieved and environments that enable good hygiene behaviour are created. Many of the factors contributing to the problem of poor living conditions and poor hygiene in these communities are outside the control of the health system. Intersectoral collaboration and action is required to identify acceptable, effective and sustainable solutions.

Scabies and pyodermas--diagnosis and treatment

Scabies and pyodermas are two of the commonest skin infections in tropical settings. They affect large numbers of people, particularly children, and account for a large burden of disease for peripheral health care teams. Despite this there have been significant advances in our knowledge of these diseases, their impact and their management. However there is a need to evaluate these developments in this specific setting, tropical health and in the context of communities with limited resources. This section will describe these advances and the challenges that remain.

Skin disorders, including pyoderma, scabies, and tinea infections

Pyoderma, scabies, and tinea are common childhood skin disorders too often considered to be merely of nuisance value. More than 111 million children are believed to have pyoderma, with many also co-infected with scabies, tinea, or both. These skin disorders cannot be differentiated by ethnicity or socioeconomic status but, in high-prevalence areas, poverty and overcrowded living conditions are important underlying social determinants. Each is transmitted primarily through direct skin-to-skin contact. For many Indigenous children, these skin conditions are part of everyday life. Although rarely directly resulting in hospitalization or death, there is a high and largely unmet demand for effective management at the primary health-care level, particularly for pyoderma and scabies. Despite particularly high prevalence in some settings, treatment is not sought for many children, and when sought, the clinical benefit from such consultations is variable. The lack of standard, evidence-based recommendations is of much concern. The current evidence base for clinical diagnosis and treatment of these common childhood skin disorders is highlighted.