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Summary: Background: Exserohilum species are environmental moulds that can cause skin infection and sinusitis in both normal and immunosuppressed children. This study reviews paediatric cases of Exserohilum infection in Queensland, Australia, to identify the spectrum of disease and its clinical course. Methods: All culture‐positive samples of Exserohilum species in children <18 years of age were identified from the Queensland Health Laboratory database (April 2003‐April 2018). Clinical information was recorded from medical records. Results: Eleven children were identified, and all had isolated Exserohilum rostratum. The mean age was 7.4 years (range 2.3‐17.8) and 64% female. Four immunocompetent children (36%) had a skin infection (2/4), chronic sinusitis (1/4) or otitis externa (1/4). Seven children (64%) had an underlying oncological diagnosis with E. rostratum causing local skin infection (2/7), invasive rhinosinus disease (3/7) or disseminated infection (2/7). All oncological patients were empirically started on liposomal amphotericin B with addition, or switch, to posaconazole or voriconazole. Conclusion: Exserohilum rostratum infection of the skin has a favourable course, whereas rhinosinus infection can be rapidly invasive in the immunocompromised child requiring prompt surgical intervention and antifungal therapy. Susceptibility data support empiric use of liposomal amphotericin and/or posaconazole. [ABSTRACT FROM AUTHOR]

Background. To expedite the evaluation of vaccines against paratyphoid fever, we aimed to develop the first human challenge model of Salmonella enterica serovar Paratyphi A infection. Methods. Two groups of 20 participants underwent oral challenge with S. Paratyphi A following sodium bicarbonate pretreatment at 1 of 2 dose levels (group 1: 1-5 × 103 colony-forming units [CFU] and group 2: 0.5-1 × 103 CFU). Participants were monitored in an outpatient setting with daily clinical review and collection of blood and stool cultures. Antibiotic treatment was started when prespecified diagnostic criteria were met (temperature =38°C for =12 hours and/or bacteremia) or at day 14 postchallenge. Results. The primary study objective was achieved following challenge with 1-5 × 103 CFU (group 1), which resulted in an attack rate of 12 of 20 (60%). Compared with typhoid challenge, paratyphoid was notable for high rates of subclinical bacteremia (at this dose, 11/20 [55%]). Despite limited symptoms, bacteremia persisted for up to 96 hours after antibiotic treatment (median duration of bacteremia, 53 hours [interquartile range, 24-85 hours]). Shedding of S. Paratyphi A in stool typically preceded onset of bacteremia. Conclusions. Challenge with S. Paratyphi A at a dose of 1-5 × 103 CFU was well tolerated and associated with an acceptable safety profile. The frequency and persistence of bacteremia in the absence of clinical symptoms was notable, and markedly different from that seen in previous typhoid challenge studies. We conclude that the paratyphoid challenge model is suitable for the assessment of vaccine efficacy using endpoints that include bacteremia and/or symptomatology. [ABSTRACT FROM AUTHOR]

Background: New Zealand's (NZ) complete absence of community transmission of influenza and respiratory syncytial virus (RSV) after May 2020, likely due to COVID‐19 elimination measures, provided a rare opportunity to assess the impact of border restrictions on common respiratory viral infections over the ensuing 2 years. Methods: We collected the data from multiple surveillance systems, including hospital‐based severe acute respiratory infection surveillance, SHIVERS‐II, ‐III and ‐IV community cohorts for acute respiratory infection (ARI) surveillance, HealthStat sentinel general practice (GP) based influenza‐like illness surveillance and SHIVERS‐V sentinel GP‐based ARI surveillance, SHIVERS‐V traveller ARI surveillance and laboratory‐based surveillance. We described the data on influenza, RSV and other respiratory viral infections in NZ before, during and after various stages of the COVID related border restrictions. Results: We observed that border closure to most people, and mandatory government‐managed isolation and quarantine on arrival for those allowed to enter, appeared to be effective in keeping influenza and RSV infections out of the NZ community. Border restrictions did not affect community transmission of other respiratory viruses such as rhinovirus and parainfluenza virus type‐1. Partial border relaxations through quarantine‐free travel with Australia and other countries were quickly followed by importation of RSV in 2021 and influenza in 2022. Conclusion: Our findings inform future pandemic preparedness and strategies to model and manage the impact of influenza and other respiratory viral threats. [ABSTRACT FROM AUTHOR]

Enteric fever is a systemic infection caused by Salmonella Typhi or Paratyphi A. In many endemic areas, these serovars co-circulate and can cause multiple infection-episodes in childhood. Prior exposure is thought to confer partial, but incomplete, protection against subsequent attacks of enteric fever. Empirical data to support this hypothesis are limited, and there are few studies describing the occurrence of heterologous-protection between these closely related serovars. We performed a challenge-re-challenge study using a controlled human infection model (CHIM) to investigate the extent of infection-derived immunity to Salmonella Typhi or Paratyphi A infection. We recruited healthy volunteers into two groups: naïve volunteers with no prior exposure to Salmonella Typhi/Paratyphi A and volunteers previously-exposed to Salmonella Typhi or Paratyphi A in earlier CHIM studies. Within each group, participants were randomised 1:1 to oral challenge with either Salmonella Typhi (104 CFU) or Paratyphi A (10³ CFU). The primary objective was to compare the attack rate between naïve and previously challenged individuals, defined as the proportion of participants per group meeting the diagnostic criteria of temperature of ≥38°C persisting for ≥12 hours and/or S. Typhi/Paratyphi bacteraemia up to day 14 post challenge. The attack-rate in participants who underwent homologous re-challenge with Salmonella Typhi was reduced compared with challenged naïve controls, although this reduction was not statistically significant (12/27[44%] vs. 12/19[63%]; Relative risk 0.70; 95% CI 0.41–1.21; p = 0.24). Homologous re-challenge with Salmonella Paratyphi A also resulted in a lower attack-rate than was seen in challenged naïve controls (3/12[25%] vs. 10/18[56%]; RR0.45; 95% CI 0.16–1.30; p = 0.14). Evidence of protection was supported by a post hoc analysis in which previous exposure was associated with an approximately 36% and 57% reduced risk of typhoid or paratyphoid disease respectively on re-challenge. Individuals who did not develop enteric fever on primary exposure were significantly more likely to be protected on re-challenge, compared with individuals who developed disease on primary exposure. Heterologous re-challenge with Salmonella Typhi or Salmonella Paratyphi A was not associated with a reduced attack rate following challenge. Within the context of the model, prior exposure was not associated with reduced disease severity, altered microbiological profile or boosting of humoral immune responses. We conclude that prior Salmonella Typhi and Paratyphi A exposure may confer partial but incomplete protection against subsequent infection, but with a comparable clinical and microbiological phenotype. There is no demonstrable cross-protection between these serovars, consistent with the co-circulation of Salmonella Typhi and Paratyphi A. Collectively, these data are consistent with surveillance and modelling studies that indicate multiple infections can occur in high transmission settings, supporting the need for vaccines to reduce the burden of disease in childhood and achieve disease control. [ABSTRACT FROM AUTHOR]

Measles continues to be a public health concern world-wide. Vulnerable individuals including those in which vaccinations is contraindicated, may be reliant on normal human immunoglobulin (NHIG) prophylaxis in an aim to prevent disease. This paper will summarise and discuss a tertiary paediatric hospital's clinical experience and the practicalities of administering intramuscular (IM) NHIG to paediatric patients as per the current measles prophylaxis guidelines in Australia. Following potential exposure within the emergency department, 17 paediatric patients (0-15 years) were recommended IM NHIG for prophylaxis. The dose of NHIG ranged from 0.6 to 15 mL and required multiple (2-8) injections. Two patients required sedation for staff to safely administer the injections. Staff involved with these cases reported administering multiple injections to paediatric patients to be a traumatising experience. They also expressed views that the injection of large volumes via the IM route was an impractical method of administration. Based on this experience, we recommend intravenous immunoglobulin be considered when large volumes of NHIG are recommended intramuscularly. [ABSTRACT FROM AUTHOR]