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Measles virus is one of the most infectious pathogenic agents and has a basic reproduction number ([R.sub.0]) of 12-18, indicating that each infected person could infect 12-18 other susceptible persons [...]

Given widespread unreported SARS-CoV-2 infections, variable immunologic response based on host immunogenicity, vaccine type, viral strain, timing and sequence of vaccine or viral exposure, and humoral waning, the global SARS-CoV-2 [...]

Background Gram-negative bloodstream infections (GNBSIs) more commonly occur in children with comorbidities and are increasingly associated with antimicrobial resistance. There are few large studies of GNBSIs in children that relate the clinical presentation, pathogen characteristics, and outcomes. Methods A 3-year prospective study of GNBSIs in children aged <18 years was conducted in 5 Australian children's hospitals between 2019 and 2021. The clinical characteristics, disease severity, and outcomes were recorded. Causative pathogens underwent antibiotic susceptibility testing and whole genome sequencing. Results There were 931 GNBSI episodes involving 818 children. Median age was 3 years (interquartile range, 0.6–8.5). A total of 576/931 episodes (62%) were community onset, though 661/931 (71%) occurred in children with comorbidities and a central venous catheter was present in 558/931 (60%). Central venous catheter (145/931) and urinary tract (149/931) were the most common sources (16% each). One hundred of 931 (11%) children required intensive care unit admission and a further 11% (105/931) developed GNBSIs in intensive care unit. A total of 659/927 (71%) isolates were Enterobacterales, of which 22% (138/630) were third-generation cephalosporin resistant (3GCR). Extended spectrum beta-lactamase genes were confirmed in 65/138 (47%) 3GCR Enterobacterales. Most common extended spectrum beta-lactamase genes were bla CTX-M-15 (34/94, 36%) and bla SHV-12 (10/94, 11%). There were 48 deaths overall and 30-day in-hospital mortality was 3% (32/931). Infections with 3GCR Enterobacterales were independently associated with higher mortality (adjusted odds ratio, 3.2; 95% confidence interval, 1.6–6.4). Conclusions GNBSIs in children are frequently healthcare associated and affect children younger than age 5 years. Infections with 3GCR Enterobacterales were associated with worse outcomes. These findings will inform optimal management guidelines and help prioritize future antimicrobial clinical trials. [ABSTRACT FROM AUTHOR]

Background: Lymphatic filariasis (LF), a mosquito-borne helminth infection, is an important cause of chronic disability globally. The World Health Organization has validated eight Pacific Island countries as having eliminated lymphatic filariasis (LF) as a public health problem, but there are limited data to support an evidence-based approach to post-validation surveillance (PVS). Tonga was validated as having eliminated LF in 2017 but no surveillance has been conducted since 2015. This paper describes a protocol for an operational research project investigating different PVS methods in Tonga to provide an evidence base for national and regional PVS strategies. Methods: Programmatic baseline surveys and Transmission Assessment Surveys conducted between 2000–2015 were reviewed to identify historically 'high-risk' and 'low-risk' schools and communities. 'High-risk' were those with LF antigen (Ag)-positive individuals recorded in more than one survey, whilst 'low-risk' were those with no recorded Ag-positives. The outcome measure for ongoing LF transmission will be Ag-positivity, diagnosed using Alere™ Filariasis Test Strips. A targeted study will be conducted in May-July 2024 including: (i) high and low-risk schools and communities, (ii) boarding schools, and (iii) patients attending a chronic-disease clinic. We estimate a total sample size of 2,010 participants. Conclusions: Our methodology for targeted surveillance of suspected 'high-risk' populations using historical survey data can be adopted by countries when designing their PVS strategies. The results of this study will allow us to understand the current status of LF in Tonga and will be used to develop the next phase of activities. [ABSTRACT FROM AUTHOR]

Background: To monitor the progress of lymphatic filariasis (LF) elimination programmes, field surveys to assess filarial antigen (Ag) prevalence require access to reliable, user-friendly rapid diagnostic tests. We aimed to evaluate the performance of the new Q Filariasis Antigen Test (QFAT) with the currently recommended Filariasis Test Strip (FTS) for detecting the Ag of Wuchereria bancrofti, the causative agent of LF, under field laboratory conditions. Methodology/Principal findings: During an LF survey in Samoa, 344 finger-prick blood samples were tested using FTS and QFAT. Microfilariae (Mf) status was determined from blood slides prepared from any sample that reported Ag-positive by either Ag-test. Each test was re-read at 1 hour and the next day to determine the stability of results over time. Overall Ag-positivity by FTS was 29.0% and 30.2% by QFAT. Concordance between the two tests was 93.6% (kappa = 0.85). Of the 101 Mf slides available, 39.6% were Mf-positive, and all were Ag-positive by both tests. Darker test line intensities from Ag-positive FTS were found to predict Mf-positivity (compared to same/lighter line intensities). QFAT had significantly higher reported test result changes than FTS, mostly reported the next day, but fewer changes were reported between 10 minutes to 1-hour. The field laboratory team preferred QFAT over FTS due to the smaller blood volume required, better usability, and easier readability. Conclusion/Significance: QFAT could be a suitable and user-friendly diagnostic alternative for use in the monitoring and surveillance of LF in field surveys based on its similar performance to FTS under field laboratory conditions. Author summary: Lymphatic filariasis (LF) is a debilitating tropical disease caused by infection with parasitic filarial worms that are transmitted by mosquitoes. Long-term infection can lead to stigmatising chronic conditions like lymphoedema and elephantiasis. The World Health Organization initiated the global programme to eliminate lymphatic filariasis (GPELF) in 2000, focusing on mass drug administration (MDA) of anti-LF drugs to stop transmission in endemic countries. However, to monitor the success of this programme and to make informed decisions to stop costly MDA, it is crucial to have access to accurate and reliable rapid diagnostics. Here, we evaluated the performance of a new rapid antigen test called the Q Filariasis antigen test and compared it to the currently recommended filariasis test strip under field laboratory conditions in Samoa. This study showed that the new rapid test could be a suitable alternative to the currently recommended test for use in GPELF-related activities with more user-friendly features. [ABSTRACT FROM AUTHOR]

Background: Lymphatic filariasis (LF) remains a significant global issue. To eliminate LF as a public health problem, the World Health Organization (WHO) recommends multiple rounds of mass drug administration (MDA). In certain scenarios, including when elimination targets have not been met with two-drug MDA, triple-drug MDA (using ivermectin, diethylcarbamazine and albendazole) is recommended. In this study, we report on antigen (Ag) and microfilaria (Mf) prevalence in eight primary sampling units (PSUs) in Samoa 4.5 years after one round of triple-drug MDA. Methodology: In 2023, community surveys were conducted in eight PSUs that had been surveyed previously in 2018 (between 1.5 and 3.5 months post triple-drug MDA) and 2019 (six to eight-months post triple-drug MDA). Fifteen houses were randomly selected in each PSU with household members aged ≥ 5 years invited to participate. Blood samples were tested for Ag and Mf. Principal findings: Ag-positive participants were observed in six of the eight PSUs, and Ag prevalence was significantly above the 1% threshold in four PSUs. The presence of Mf-positive participants in five PSUs confirms the presence of residual active infections. Conclusions/Significance: This study provides evidence of persistent LF transmission in Samoa 4.5 years after one round of triple-drug MDA, confirming that one round was insufficient for interruption of transmission in this setting. Our findings highlight the negative impact of delaying MDA rounds, for example, due to public health emergencies. Author summary: The World Health Organization (WHO) recommends triple-drug mass drug administration (MDA) for the elimination of lymphatic filariasis (LF) as a public health problem for countries where targets have not been achieved using two-drug MDA, and where onchocerciasis is non-endemic. In 2018, Samoa was the first country to implement a national triple-drug MDA. This study surveyed 623 randomly selected participants across eight primary sampling units (PSUs) in Samoa, 4.5 years after the first round of triple-drug MDA. These results support the current WHO recommendations that multiple rounds of triple-drug MDA are required to interrupt transmission. A gap of 4.5 years between rounds of triple-drug MDA can result in a resurgence, with persistence of LF transmission and burden levels comparable to those observed before the MDA. [ABSTRACT FROM AUTHOR]

Background Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers returning to non-endemic areas can provide valuable data to inform endemic country programmes. To evaluate the potential for novel global insights into malaria, we examined epidemiological and molecular data from imported malaria cases to Australia. Methods We analysed malaria cases reported in Australia from 2012 to 2022 using National Notifiable Disease Surveillance System data. Molecular data on imported malaria cases were obtained from literature searches. Results Between 2012 and 2022, 3204 malaria cases were reported in Australia. Most cases (69%) were male and 44% occurred in young adults aged 20–39 years. Incidence rates initially declined between 2012 and 2015, then increased until 2019. During 2012–2019, the incidence in travellers ranged from 1.34 to 7.71 per 100 000 trips. Cases were primarily acquired in Sub-Saharan Africa (n  = 1433; 45%), Oceania (n  = 569; 18%) and Southern and Central Asia (n  = 367; 12%). The most common countries of acquisition were Papua New Guinea (n  = 474) and India (n  = 277). Plasmodium falciparum accounted for 58% (1871/3204) of cases and was predominantly acquired in Sub-Saharan Africa, and Plasmodium vivax accounted for 32% (1016/3204), predominantly from Oceania and Asia. Molecular studies of imported malaria cases to Australia identified genetic mutations and deletions associated with drug resistance and false-negative rapid diagnostic test results, and led to the establishment of reference genomes for P. vivax and Plasmodium malariae. Conclusions Our analysis highlights the continuing burden of imported malaria into Australia. Molecular studies have offered valuable insights into drug resistance and diagnostic limitations, and established reference genomes. Integrating molecular data into national surveillance systems could provide important infectious disease intelligence to optimize treatment guidelines for returning travellers and support endemic country surveillance programmes. [ABSTRACT FROM AUTHOR]

Background: International travel can increase the risk of exposure to infectious diseases including sexually transmissible infections (STI). Pre-travel medical consultation provides an opportunity for travel-related health risk assessments and advice. This study explored how travel medicine clinicians integrate sexual and reproductive health (SRH) services into clinical practice. Methods: A convenience sample of travel medicine clinicians completed a cross-sectional survey online or via hard-copy disseminated at an annual national Australian travel medicine conference. Results: Of the 67 respondents, most (n , 51; 76.1%) had a postgraduate qualification relevant to travel medicine and 55.2% (n , 37) had worked in travel medicine for over 10 years. Only 22.4% (n , 15) reported conducting a SRH history/STI risk assessment for all travel patients. STI testing pre-departure was conducted on patient request (48, 71.6%), if symptomatic (32, 47.8%) or based on risk history (28, 41.8%). SRH information pre-departure was most frequently provided if prompted by patient questions (n , 42; 62.7%), or based on the patient's history (n , 37; 55.2%). Over half the sample (n , 40; 59.7%) expressed interest in further training in SRH. Conclusion: Providing and engaging with additional training may assist travel medicine clinicians to take a more proactive approach to SRH consultations and STI testing. Additional research is needed to explore models of care that will allow comprehensive SRH and STI services to be integrated into standard pre- and post-travel care. International travel can increase the risk of exposure to infectious diseases including sexually transmissible infections and human immunodeficiency virus. This study explored how travel medicine clinicians integrate sexual and reproductive health (SRH) services into clinical practice. Our findings highlighted gaps in the provision of pre-travel consultation and training needs for SRH among travel medicine clinicians, and the potential for improved promotion of sexual health among travellers to provide important public health benefits for individuals and the wider community. [ABSTRACT FROM AUTHOR]

Zika virus and chikungunya virus (CHIKV) have caused outbreaks in several tropical regions, including the Pacific (1). The first known Zika virus outbreak occurred in Yap Island (Federated States of [...]

Ross River virus (RRV) is an Alphavirus of the family Togaviridae and is transmitted to humans by Aedes and Culexmosquitoes (1). Marsupials are considered important reservoirs of RRV (1). Clinical [...]

The article discusses the growing concern of arboviral diseases such as dengue and chikungunya in travelers. The United States has recently approved the world's first chikungunya vaccine, which has shown promising results in terms of seroresponse and clinical benefit. The article also highlights the increasing incidence of dengue in travelers and the availability of a new dengue vaccine. The recommendations for the use of these vaccines vary among different expert groups, but the authors argue for broader recommendations to address the high burden of these diseases. Further research is needed to gather more data on the vaccines' effectiveness, safety, and duration of protection. [Extracted from the article]

This article discusses the use of the Dengvaxia® vaccine in Australian travelers. Dengue fever is a mosquito-borne viral disease that can cause severe complications. Dengvaxia® is a live recombinant tetravalent dengue vaccine that was licensed in Mexico in 2015 and has since been approved in over 20 countries. In Australia, Dengvaxia® is recommended for long-term travelers aged 9-45 years who have had previous dengue infection and plan to reside in highly dengue-endemic regions. However, its use in Australia has been limited due to strict criteria and high cost. A case series of seven travelers who received Dengvaxia® at a travel medicine clinic in Brisbane found that the vaccine was well-tolerated, with only mild to moderate adverse events reported. It is important to note that most travelers from non-endemic countries should not receive Dengvaxia® as they are seronegative and may be at risk of severe dengue. While another dengue vaccine, Qdenga®, is available in some countries, Dengvaxia® remains the only option for Australian travelers at present. The study acknowledges its limitations, including the small sample size and the fact that it represents the experience of one clinic. Overall, Dengvaxia® has been rarely used in Australia but may be considered in certain circumstances. [Extracted from the article]

Background Neonatal sepsis is a significant global health issue associated with marked regional disparities in mortality. Antimicrobial resistance (AMR) is a growing concern in Gram-negative organisms, which increasingly predominate in neonatal sepsis, and existing WHO empirical antibiotic recommendations may no longer be appropriate. Previous systematic reviews have been limited to specific low- and middle-income countries. We therefore completed a systematic review and meta-analysis of available data from all low- and lower-middle-income countries (LLMICs) since 2010, with a focus on regional differences in Gram-negative infections and AMR. Methods and findings All studies published from 1 January 2010 to 21 April 2021 about microbiologically confirmed bloodstream infections or meningitis in neonates and AMR in LLMICs were assessed for eligibility. Small case series, studies with a small number of Gram-negative isolates ( Conclusions Gram-negative bacteria are an important cause of neonatal sepsis in LLMICs and are associated with significant rates of resistance to WHO-recommended first- and second-line empirical antibiotics. AMR surveillance should underpin region-specific empirical treatment recommendations. Meanwhile, a significant global commitment to accessible and effective antimicrobials for neonates is required., Author(s): Sophie C. H. Wen 1,2,*, Yukiko Ezure 1,3, Lauren Rolley 2, Geoff Spurling 4, Colleen L. Lau 3,5, Saba Riaz 6, David L. Paterson 1,7, Adam D. Irwin 1,2 [...]

With an estimated disease burden of 20.6 million cases in low- and middle-income countries in 2010, typhoid fever remains an enteric disease of public health concern (1,2). Typhoid fever cases [...]

Background During pre-travel consultations, clinicians and travellers face the challenge of weighing the risks verus benefits of Japanese encephalitis (JE) vaccination due to the high cost of the vaccine, low incidence in travellers (~1 in 1 million), but potentially severe consequences (~30% case-fatality rate). Personalised JE risk assessment based on the travellers' demographics and travel itinerary is challenging using standard risk matrices. We developed an interactive digital tool to estimate risks of JE infection and severe health outcomes under different scenarios to facilitate shared decision-making between clinicians and travellers. Methods A Bayesian network (conditional probability) model risk–benefit analysis of JE vaccine in travellers was developed. The model considers travellers' characteristics (age, sex, co-morbidities), itinerary (destination, departure date, duration, setting of planned activities) and vaccination status to estimate the risks of JE infection, the development of symptomatic disease (meningitis, encephalitis), clinical outcomes (hospital admission, chronic neurological complications, death) and adverse events following immunization. Results In low-risk travellers (e.g. to urban areas for <1 month), the risk of developing JE and dying is low (<1 per million) irrespective of the destination; thus, the potential impact of JE vaccination in reducing the risk of clinical outcomes is limited. In high-risk travellers (e.g. to rural areas in high JE incidence destinations for >2 months), the risk of developing symptomatic disease and mortality is estimated at 9.5 and 1.4 per million, respectively. JE vaccination in this group would significantly reduce the risk of symptomatic disease and mortality (by ~80%) to 1.9 and 0.3 per million, respectively. Conclusion The JE tool may assist decision-making by travellers and clinicians and could increase JE vaccine uptake. The tool will be updated as additional evidence becomes available. Future work needs to evaluate the usability of the tool. The interactive, scenario-based, personalised JE vaccine risk–benefit tool is freely available on www.VaxiCal.com. [ABSTRACT FROM AUTHOR]

Periodic vaccination against rabies is essential for individuals at continuing risk of rabies exposure. There is limited evidence on long‐term immunogenicity after a 3‐dose intramuscular (3IM) pre‐exposure prophylaxis (PrEP) and single IM booster dose, thus current guideline recommendations differ in the interval for serology tests following PrEP and boosters. This study investigated post‐PrEP and post‐booster persistence of antibodies in Australian bat carers. Bat carers who received 3IM PrEP/booster doses and had post‐PrEP/booster serology test results were included. The proportion of antibody‐negative (<0.5 EU/mL) individuals after PrEP/booster dose were examined. Three hundred and five participants (65.6% females, median age at PrEP 43.1 years) were included. The proportion who were antibody‐negative varied depending on the time between 3IM PrEP and the serology test: 8.0% <1 year, 29.8% 1–2 years, 21.2% 2–3 years and 7.7% >3 years. Ninety‐one participants receiving booster doses were further assessed. Only one participant was antibody‐negative at >3 years after receiving one IM booster dose. Our findings support that a serology test should be performed 1 year after 3IM PrEP, followed by first booster if required. Rabies antibodies persist for many years after receiving the booster doses. The interval between subsequent serology tests and the first booster dose should be no longer than 3 years. Future studies are required to provide more insight into the most appropriate timing of subsequent boosters. [ABSTRACT FROM AUTHOR]

Background: Scabies is a common skin infestation caused by the Sarcoptes scabei mite. Ivermectin, one of three drugs used in mass drug administration (MDA) for lymphatic filariasis, is also effective for treating scabies. Ivermectin-based MDA was first conducted in Samoa in August 2018, with ivermectin being offered to those aged ≥5 years. Here, we report scabies prevalence in Samoa after MDA. Methods: We conducted household surveys 1.5–3.5 months (Survey 1) and 6–8 months (Survey 2) after the 2018 MDA in 35 primary sampling units. We conducted clinical examination for scabies-like rash and used International Alliance for the Control of Scabies classification criteria. We estimated scabies prevalence by age, gender and region. Multivariable logistic regression was used to assess factors associated with prevalence. Results: We surveyed 2868 people (499 households) and 2796 people (544 households) aged 0–75 years in Surveys 1 and 2, respectively. Scabies prevalence increased from 2.4% (95% CI 2.1–2.7%) to 4.4% (95% CI 4.0–4.9%) between surveys. Scabies was associated with younger age (0–4 years: aOR 3.5 [2.9–4.2]; 5–15 years: aOR 1.6 [1.4–1.8] compared to ≥16 years), female gender (aOR 1.2 [95% CI 1.1–1.4]; region (aOR range from 1.4 [1.1–1.7] to 2.5 [2.1–3.1] between regions), large households (aOR 2.6 [2.0–3.4] households ≥13), and not taking MDA in 2018 (aOR 1.3 [95% CI 1.1–1.6]). Conclusions: We found moderate prevalence of scabies in two population-representative surveys conducted within 8 months of the 2018 MDA for lymphatic filariasis. Prevalence appeared to increase between the surveys, and ongoing surveillance is recommended, particularly in young children. Author summary: Scabies is a common skin disease that is caused by a small mite that burrows into the skin. It can be treated by a drug called ivermectin, which was given to every person aged 5 years and over in Samoa in 2018 to treat a different disease, known as lymphatic filariasis. We wanted to understand how common scabies was in the people of Samoa and so did two surveys where we visited people's houses that we randomly selected. We and asked people in each household questions about scabies symptoms and looked at their skin for signs of scabies. We surveyed 2868 people in 499 households in the first survey and 2796 in 544 households in the second survey. We found that 2.4% of people in the first survey and 4.4% of people in the second survey had scabies. We also found that some people were more likely to have scabies: younger children, women, people living in some regions of Samoa, people living with more people in their household, and people who didn't take the medicine for lymphatic filariasis in 2018. [ABSTRACT FROM AUTHOR]