Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa

BackgroundThe burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with Salmonella enterica serovar Typhi (S. Typhi) as an important cause of bacteremia in children.MethodsA total of 128 S. Typhi isolates from these studies in Nigeria were whole-genome sequenced, and the resulting data was used to place these Nigerian isolates into a worldwide context based on their phylogeny and carriage of molecular determinants of antibiotic resistance.ResultsSeveral distinct S. Typhi genotypes were identified in Nigeria that were related to other clusters of S. Typhi isolates from north, west and central regions of Africa. The rapidly expanding S. Typhi clade 4.3.1 (H58) previously associated with multiple antimicrobial resistances in Asia and in east, central and southern Africa, was not detected in this study. However, antimicrobial resistance was common amongst the Nigerian isolates and was associated with several plasmids, including the IncHI1 plasmid commonly associated with S. Typhi.ConclusionsThese data indicate that typhoid in Nigeria was established through multiple independent introductions into the country, with evidence of regional spread. MDR typhoid appears to be evolving independently of the haplotype H58 found in other typhoid endemic countries. This study highlights an urgent need for routine surveillance to monitor the epidemiology of typhoid and evolution of antimicrobial resistance within the bacterial population as a means to facilitate public health interventions to reduce the substantial morbidity and mortality of typhoid

Comparing age and sex trends of chlamydia, gonorrhoea, hepatitis and syphilis infections in Samoa in 2012 and 2017

In Samoa, the seroprevalence rates of sexually transmitted infections other than HIV have been endemically high over the past decade, despite years of prevention programming. Odds ratio and χ2 tests were conducted to compare the rates of positivity of chlamydia, gonorrhoea, hepatitis B and C, and syphilis across age groups from 2012 and 2017 surveillance data in Samoa. Young people aged 15–19 years were significantly more likely to have a chlamydia infection compared to all other age groups in both 2012 and 2017. Hepatitis B infections were more common in males and those aged 30 and above in both 2012 and 2017. Hepatitis C had no significant differences in age, but it was more common in males in 2012 and more common in females in 2017. Older age groups (aged 45 and above) were more likely to have a positive syphilis test in both 2014 and 2017 when compared to those aged 15–24 years. The results of this analysis confirm previously observed trends in Samoa for younger age groups’ prevalence of chlamydia and gonorrhoea, and for older age groups’ prevalence of hepatitis B and C. But the analysis also unexpectedly found that older age groups (aged 45 and above) are more likely to test positive for syphilis (for years 2014 and 2017). Further studies are needed to assess behavioural risk factors associated with older populations in order to explain the increase in risk and to design interventions suited to this demographic.</jats:p

The application of ctDNA technology for early Cancer diagnostics in Samoa

Abstract Fragmented pieces of tumor DNA can be found in the human blood circulation. These tumor DNA fragments can be isolated and quantified to produce detailed information related to cancer progression and treatment responses in patients. This monitoring and analysis comprises a novel cancer detection method known as circulating tumor DNA (ctDNA). Given that gaining access to and obtaining biopsy samples from solid cancers in people is not always possible or as straightforward as needed, the utilization of a simple blood sample to allow detection and monitoring of cancer growth and behavior is highly desirable. This simple detection and monitoring technology is likely enhance the precision of cancer care for patients, and support early cancer detection. The purpose of this work was to explore in detail the potential for ctDNA to be utilized as an early cancer detection tool within the healthcare setting within the Pacific in Samoa. Consultation was sought with senior Government officials, Medical, Nursing, Health and Community research staff concerning the development and implementation of ctDNA as a diagnostic tool within the clinical health care setting throughout Samoa. The application of the ctDNA technology as an early cancer detection tool within the clinical healthcare setting was explored in depth and received with approval, given issues that currently exist concerning resource constraints and late cancer presentations. It is anticipated that the utility of ctDNA as an early cancer detection tool will support improved cancer management within the health care setting in Samoa.</jats:p

The Benzathine Penicillin G (BPG) Reformulation Preferences Study - Samoa

Abstract Acute Rheumatic Fever (ARF) is an autoimmune condition caused by untreated group A streptococcal (GAS) infection of the upper respiratory tract (and possibly skin). Multiple or severe attacks of ARF can cause cardiac damage known as rheumatic heart disease (RHD). In Australia, New Zealand (NZ) and the Pacific Region, the disease burden of ARF and RHD amongst Indigenous and Pacific communities is one of the highest in the world, usually affecting children and young adults. The most effective recommended management for ARF requires monthly intramuscular injections of 1.2 million units of Benzathine Penicillin G (BPG) known as secondary prophylaxis (SP) for 10 years or more. The goal of SP is to prevent GAS infections that may lead to the recurrence of ARF. Even with these monthly BPG injections, adherence to SP schedules are usually low due to the frequency and duration of injection, pain and access to proper and timely healthcare. A less painful and longer acting BPG formulation would ideally help prevent recurrence of ARF and improve compliance rates to this schedule with improved understanding of barriers and novel approaches to BPG delivery urgently needed. To better understand the BPG reformulation preferences of children/teens currently receiving monthly BPG intramuscular injections, and that of their families and healthcare providers who administer BPG, three software applications will be developed from pre-existing applications that have been optimized for use in target populations in New Zealand. This will be the first time software applications have been used to collect qualitative and quantitative data on individual preferences for BPG formulations and dosing regimens in Samoa.</jats:p

Estimating mean population salt intake in Fiji and Samoa using spot urine samples

Abstract Background There is an increasing interest in finding less costly and burdensome alternatives to measuring population-level salt intake than 24-h urine collection, such as spot urine samples. However, little is known about their usefulness in developing countries like Fiji and Samoa. The purpose of this study was to evaluate the capacity of spot urine samples to estimate mean population salt intake in Fiji and Samoa. Methods The study involved secondary analyses of urine data from cross-sectional surveys conducted in Fiji and Samoa between 2012 and 2016. Mean salt intake was estimated from spot urine samples using six equations, and compared with the measured salt intake from 24-h urine samples. Differences and agreement between the two methods were examined through paired samples t-test, intraclass correlation coefficient analysis, and Bland-Altman plots and analyses. Results A total of 414 participants from Fiji and 725 participants from Samoa were included. Unweighted mean salt intake based on 24-h urine collection was 10.58 g/day (95% CI 9.95 to 11.22) in Fiji and 7.09 g/day (95% CI 6.83 to 7.36) in Samoa. In both samples, the INTERSALT equation with potassium produced the closest salt intake estimate to the 24-h urine (difference of − 0.92 g/day, 95% CI − 1.67 to − 0.18 in the Fiji sample and + 1.53 g/day, 95% CI 1.28 to 1.77 in the Samoa sample). The presence of proportional bias was evident for all equations except for the Kawasaki equation. Conclusion These data suggest that additional studies where both 24-h urine and spot urine samples are collected are needed to further assess whether methods based on spot urine samples can be confidently used to estimate mean population salt intake in Fiji and Samoa. </jats:sec

Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events

The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species