Serosurvey for Japanese encephalitis virus antibodies following an outbreak in an immunologically naïve population, Victoria, 2022: a cross-sectional study.

OBJECTIVES: To investigate the distribution and prevalence of Japanese encephalitis virus (JEV) antibody (as evidence of past infection) in northern Victoria following the 2022 Japanese encephalitis outbreak, seeking to identify groups of people at particular risk of infection; to investigate the distribution and prevalence of antibodies to two related flaviviruses, Murray Valley encephalitis virus (MVEV) and West Nile virus Kunjin subtype (KUNV). STUDY DESIGN: Cross-sectional serosurvey (part of a national JEV serosurveillance program). SETTING: Three northern Victorian local public health units (Ovens Murray, Goulburn Valley, Loddon Mallee), 8 August - 1 December 2022. PARTICIPANTS: People opportunistically recruited at pathology collection centres and by targeted recruitment through community outreach and advertisements. People vaccinated against or who had been diagnosed with Japanese encephalitis were ineligible for participation, as were those born in countries where JEV is endemic. MAIN OUTCOME MEASURES: Seroprevalence of JEV IgG antibody, overall and by selected factors of interest (occupations, water body exposure, recreational activities and locations, exposure to animals, protective measures). RESULTS: 813 participants were recruited (median age, 59 years [interquartile range, 42-69 years]; 496 female [61%]); 27 were JEV IgG-seropositive (3.3%; 95% confidence interval [CI], 2.2-4.8%) (median age, 73 years [interquartile range, 63-78 years]; 13 female [48%]); none were IgM-seropositive. JEV IgG-seropositive participants were identified at all recruitment locations, including those without identified cases of Japanese encephalitis. The only risk factors associated with JEV IgG-seropositivity were age (per year: prevalence odds ratio [POR], 1.07; 95% CI, 1.03-1.10) and exposure to feral pigs (POR, 21; 95% CI, 1.7-190). The seroprevalence of antibody to MVEV was 3.0% (95% CI, 1.9-4.5%; 23 of 760 participants), and of KUNV antibody 3.3% (95% CI, 2.1-4.8%; 25 of 761). CONCLUSIONS: People living in northern Victoria are vulnerable to future JEV infection, but few risk factors are consistently associated with infection. Additional prevention strategies, including expanding vaccine eligibility, may be required to protect people in this region from Japanese encephalitis.

Population vulnerability to heat: A case-crossover analysis of heat health alerts and hospital morbidity data in Victoria, Australia.

OBJECTIVE: From 2010 to 2022, the Victorian Department of Health operated a heat health alert system. We explored whether changes to morbidity occurred during or directly after these alerts, and how this differed for certain population groups. METHODS: We used a space-time-stratified case-crossover design and conditional logistic regression to examine the associations between heat health alerts and heat-related and all-cause emergency department (ED) presentations and hospital admissions at the state-wide level, with models created for the whole population and subgroups. Data were included for the warm season (November-March) from 2014 to 2021. RESULTS: Increases occurred in heat-related ED presentations (OR 1.73, 95% CI: 1.53-1.96) and heat-related hospital admissions (OR 1.23, 95% CI: 1.16-1.30) on days on or after heat health alerts. Effect sizes were largest for those 65 years and older, Aboriginal and Torres Strait Islander people, and those living in the most disadvantaged areas. CONCLUSIONS: We confirm that increases in morbidity occurred in Victoria during heat health alerts and describe which population groups are more likely to require healthcare in a hospital. IMPLICATIONS FOR PUBLIC HEALTH: These findings can inform responses before and during periods of extreme heat, data-driven adaptation strategies, and the development of heat health surveillance systems.

A foodborne outbreak of campylobacteriosis at a wedding - Melbourne, Australia, 2022.

Campylobacter is the most common bacterial cause of foodborne gastroenteritis in Australia; however, outbreaks caused by the pathogen are relatively uncommon. In March 2022, the Victorian Department of Health was notified of a gastrointestinal illness in 20 guests following attendance at a wedding reception. Two of these individuals were notified with laboratory-confirmed campylobacteriosis, and an investigation was undertaken to identify the source of the infection and implement strategies to prevent further illness. A case-control study was conducted to determine the likely source of infection. Cases were defined as attendees of the wedding reception, with onset of diarrhoea and/or abdominal cramping 1-10 days after attending the function. Controls were randomly selected from the remaining list of non-ill guests. Cases and controls were interviewed using a standardised, menu-based questionnaire. Food preparation processes were documented, and food samples collected. A total of 29 wedding guests met the case definition. Cases reported onset of illness 2-5 days following the wedding and major symptoms included abdominal cramping (100%), diarrhoea (90%), headache (79%), and fever (62%). Two cases were hospitalised, one with ongoing secondary neurological sequelae. Illness was significantly associated with consumption of a duck breast brioche canapé containing duck liver parfait (odds ratio = 2.85; 95% confidence interval: 1.03-7.86). No leftover food samples were available for testing. The investigation found that the duck canapé was the likely vehicle of infection. Consistent with the literature on Campylobacter transmission, it is likely that inadequate cooking of the duck liver for the parfait was the contributing factor that led to illness. This highlights the risks posed by undercooked poultry dishes, and shows that education of food handlers remains a priority.

Update on mortality in the Democratic Republic of Congo: results from a third nationwide survey.

BACKGROUND: The humanitarian crisis in the Democratic Republic of Congo (DRC) has been among the world's deadliest in recent decades. We conducted our third nationwide survey to examine trends in mortality rates during a period of changing political, security, and humanitarian conditions. METHODS: We used a 3-stage, household-based cluster sampling technique to compare east and west DRC. Sixteen east health zones and 15 west zones were selected with a probability proportional to population size. Four east zones were purposely selected to allow historical comparisons. The 20 smallest population units were sampled in each zone, 20 households in each unit. The number and distribution of households determined whether they were selected using systematic random or random walk sampling. Respondents were asked about deaths of household members during the recall period: January 2006-April 2007. FINDINGS: In all, 14,000 households were visited. The national crude mortality rate of 2.2 deaths per 1000 population per month (95% confidence interval [CI] 2.1-2.3) is almost 70% higher than that documented for DRC in the 1984 census (1.3) and is unchanged since 2004. A small but significant decrease in mortality since 2004 in the insecure east (rate ratio: 0.96, P = .026) was offset by increases in the western provinces and a transition area in the center of the country. Nonetheless, the crude mortality rate in the insecure east (2.6) remains significantly higher than in the other regions (2.0 and 2.1, respectively). Deaths from violence have declined since 2004 (rate ratio 0.7, P = .02). CONCLUSIONS: More than 4 years after the official end of war, the crude mortality rate remains elevated across DRC. Slight but significant improvements in mortality in the insecure east coincided temporally with recent progress on security, humanitarian, and political fronts.

Implementing the birth dose of hepatitis B vaccine in rural Indonesia.

Reaching mothers and their newborn infants around the time of birth with adequate health services has long been a difficult problem in developing countries. In parallel, similar problems have arisen in attempting to deliver hepatitis B (HepB) vaccine to infants born at home in many countries where mother-to-infant transmission is common. It is logical, and supported by experience in Indonesia, to find a combined solution for both problems. The World Health Organization (WHO) recommends that a timely birth dose of HepB vaccine be given, particularly in areas of high vertical transmission of hepatitis B virus (HBV). This can be achieved relatively easily in situations where almost all births occur in health facilities. But where a significant proportion of births occur at home and without birth attendants able to give injections, this is much more difficult. Barriers to the timely administration of the birth dose of HepB vaccine include weakness in policy development and implementation, difficulties in reliably supplying potent vaccine to community level, limited transport, poor communication, limited cold chain capacity, lack of effective training, and lack of a clear delineation of responsibility between health care professionals. Demonstration projects, such as those in Indonesia, suggest that there are significant opportunities to improve the timely delivery of HepB vaccine birth dose in existing maternal and child health programmes where health workers are trained to provide home delivery care.

Hepatitis E virus infection as a marker for contaminated community drinking water sources in Tibetan villages.

In April-May 2001, a study was conducted to determine the prevalence of antibodies against hepatitis E virus (HEV) among 426 persons 8-49 years of age randomly selected from two groups of rural villages in central Tibet. Group 1 villages were assessed in 1998 as having poor quality water sources; new water systems were then constructed prior to this study. Group 2 villages had higher quality water and were not designated as priority villages for new systems prior to the study. No participants tested positive for IgM; only IgG was detected in the analyzed samples. Overall, 31% of the participants had ever been infected with HEV (95% confidence interval [CI] = 26.7-35.7%). The rate was higher in men (36.6%) than women (26.3%) and highest in those 30-39 years of age (49.1%). The rate of past infection was higher in group 1; the risk ratio was 2.77 (95% CI = 1.98-3.88). This difference is most likely the result of the poor quality of the original water sources in these villages. In resource-poor countries, HEV may be a useful health indicator reflecting the degree of contamination in village water sources. This may be especially important in rural areas (such as Tibet) where maternal mortality ratios are high because HEV may be an important cause of deaths during pregnancy in disease-endemic areas.

Mortality in the Democratic Republic of Congo: a nationwide survey.

BACKGROUND: Commencing in 1998, the war in the Democratic Republic of Congo has been a humanitarian disaster, but has drawn little response from the international community. To document rates and trends in mortality and provide recommendations for political and humanitarian interventions, we did a nationwide mortality survey during April-July, 2004. METHODS: We used a stratified three-stage, household-based cluster sampling technique. Of 511 health zones, 49 were excluded because of insecurity, and four were purposely selected to allow historical comparisons. From the remainder, probability of selection was proportional to population size. Geographical distribution and size of cluster determined how households were selected: systematic random or classic proximity sampling. Heads of households were asked about all deaths of household members during January, 2003, to April, 2004. FINDINGS: 19,500 households were visited. The national crude mortality rate of 2.1 deaths per 1000 per month (95% CI 1.6-2.6) was 40% higher than the sub-Saharan regional level (1.5), corresponding to 600,000 more deaths than would be expected during the recall period and 38,000 excess deaths per month. Total death toll from the conflict (1998-2004) was estimated to be 3.9 million. Mortality rate was higher in unstable eastern provinces, showing the effect of insecurity. Most deaths were from easily preventable and treatable illnesses rather than violence. Regression analysis suggested that if the effects of violence were removed, all-cause mortality could fall to almost normal rates. INTERPRETATION: The conflict in the Democratic Republic of Congo remains the world's deadliest humanitarian crisis. To save lives, improvements in security and increased humanitarian assistance are urgently needed.