Global perspectives for prevention of infectious diseases associated with mass gatherings

Illness in travelers returned from Brazil: the GeoSentinel experience and implications for the 2014 FIFA World Cup and the 2016 Summer Olympics

BACKGROUND

Brazil will host the 2014 FIFA World Cup and the 2016 Olympic and Paralympic Games, events that are expected to attract hundreds of thousands of international travelers. Travelers to Brazil will encounter locally endemic infections as well as mass event-specific risks.

METHODS

We describe 1586 ill returned travelers who had visited Brazil and were seen at a GeoSentinel Clinic from July 1997 through May 2013.

RESULTS

The most common travel-related illnesses were dermatologic conditions (40%), diarrheal syndromes (25%), and febrile systemic illness (19%). The most common specific dermatologic diagnoses were cutaneous larva migrans, myiasis, and tungiasis. Dengue and malaria, predominantly Plasmodium vivax, were the most frequently identified specific causes of fever and the most common reasons for hospitalization after travel. Dengue fever diagnoses displayed marked seasonality, although cases were seen throughout the year. Among the 28 ill returned travelers with human immunodeficiency virus (HIV) infection, 11 had newly diagnosed asymptomatic infection and 9 had acute symptomatic HIV.

CONCLUSIONS

Our analysis primarily identified infectious diseases among travelers to Brazil. Knowledge of illness in travelers returning from Brazil can assist clinicians to advise prospective travelers and guide pretravel preparation, including itinerary-tailored advice, vaccines, and chemoprophylaxis; it can also help to focus posttravel evaluation of ill returned travelers. Travelers planning to attend mass events will encounter other risks that are not captured in our surveillance network.

Impact of a labour disruption affecting local public health on the incidence of chlamydia infections in Toronto

Introduction

Labour disruptions that interrupt services can be a natural experiment to examine the effect of halting a program. A five-week municipal labour disruption in Toronto during the summer of 2009 provided an opportunity to investigate the impact of reduced sexual health services.

Methods

We examined the incidence of reported chlamydia in Toronto during the five years (2004–2008) preceding the labour disruption and during the periods just before, during, and after the labour disruption. Comparisons of actual reports for 2009 were made to immediately adjacent periods around the labour disruption, to historical trends and to forecasted rates. Interrupted time series analysis was used to test for significant differences in the trend of reported chlamydia incidence.

Results

There was no significant difference in the trend of reported chlamydia incidence around the time of the strike. However, there was a small but significant increase in the incidence of reported chlamydia, particularly among females under 25 years old immediately following the labour disruption. The reported incidence for this group was higher than would be expected based on annual increases and projected seasonal trends.

Conclusions

There was a small increase in incidence of reported cases of chlamydia for certain groups that went beyond what is expected during the time immediately following the labour disruption. While causation cannot be implied from our ecological study, public health services may play a role in the control of sexually transmitted infections, even in the short-term. This underscores the need for future work to understand whether the changes observed can be attributed to the absence of these services.

Respiratory tract infections during the annual Hajj: potential risks and mitigation strategies

PURPOSE OF REVIEW

Mass gatherings such as religious pilgrimages, sporting events and music concerts are becoming larger and more frequent. The scale and frequency of large-scale international events pose substantial risks to the spread of infectious diseases. The available literature on respiratory tract infections at the Hajj pilgrimage - annually attended by 3 million pilgrims from all over the globe - are reviewed.

RECENT FINDINGS

The most common respiratory tract infection viruses are influenza and rhinovirus. Despite the occurrence of the Hajj during the 2009 H1N1 pandemic the available literature did not show an increased rate of infection. In hospitalized patients, pneumonia is a significant cause of admission accounting for 20-50% of such admissions.

SUMMARY

The use of masks may reduce exposure to droplet nuclei, the main mode of transmission of most respiratory tract infections. The practice of social distancing, hand hygiene, and contact avoidance was associated with reduced risk of respiratory illness. In addition, utilizing the recommended vaccines would decrease the risk of acquiring respiratory tract pathogens.

Hajj pilgrims knowledge about Middle East respiratory syndrome coronavirus, August to September 2013

In preparation for Hajj 2013, 360 French pilgrims were interviewed regarding their knowledge about Middle East respiratory syndrome (MERS). Respondents were aged 20–85 years, male-female ratio was 1.05:1;64.7% were aware of the MERS situation in Saudi Arabia; 35.3% knew about the Saudi Ministry of Health recommendations for at-risk pilgrims to postpone participation in the 2013 Hajj. None of 179 at-risk individuals(49.9%) decided to cancel their Hajj participation even after advice during consultation.

Estimating potential infection transmission routes in hospital wards using wearable proximity sensors

Background

Contacts between patients, patients and health care workers (HCWs) and among HCWs represent one of the important routes of transmission of hospital-acquired infections (HAI). A detailed description and quantification of contacts in hospitals provides key information for HAIs epidemiology and for the design and validation of control measures.

Methods and Findings

We used wearable sensors to detect close-range interactions (“contacts”) between individuals in the geriatric unit of a university hospital. Contact events were measured with a spatial resolution of about 1.5 meters and a temporal resolution of 20 seconds. The study included 46 HCWs and 29 patients and lasted for 4 days and 4 nights. 14,037 contacts were recorded overall, 94.1% of which during daytime. The number and duration of contacts varied between mornings, afternoons and nights, and contact matrices describing the mixing patterns between HCW and patients were built for each time period. Contact patterns were qualitatively similar from one day to the next. 38% of the contacts occurred between pairs of HCWs and 6 HCWs accounted for 42% of all the contacts including at least one patient, suggesting a population of individuals who could potentially act as super-spreaders.

Conclusions

Wearable sensors represent a novel tool for the measurement of contact patterns in hospitals. The collected data can provide information on important aspects that impact the spreading patterns of infectious diseases, such as the strong heterogeneity of contact numbers and durations across individuals, the variability in the number of contacts during a day, and the fraction of repeated contacts across days. This variability is however associated with a marked statistical stability of contact and mixing patterns across days. Our results highlight the need for such measurement efforts in order to correctly inform mathematical models of HAIs and use them to inform the design and evaluation of prevention strategies.

International infectious disease surveillance during the London Olympic and Paralympic Games 2012: process and outcomes

Surveillance for possible international infectious disease threats to the Olympic and Paralympic Games in London, United Kingdom, was conducted from 2 July to 12 September 2012 by a collaborative team comprising representatives from the Health Protection Agency (Public Health England since April 2013), the European Centre for Disease Prevention and Control and the National Travel Health Network and Centre. Team members enhanced their usual international surveillance activities and undertook joint risk assessments of incidents identified as relevant through an agreed set of criteria designed for the Games and using tools developed for this purpose. Although team members responded to a range of international disease incidents as part of their routine roles during this period, no incident was identified that represented a threat to the Games. Six incidents were highlighted by the team that were likely to attract media attention and hence could generate political and public concern. Responding to such concern is an important aspect of the overall public health management of mass gathering events. The lessons learned about the process and outcomes of the enhanced international surveillance will help inform planning by future hosts of similar events.

Infections associated with religious rituals

This review evaluates the medical literature for religious rituals or ceremonies that have been reported to cause infection. These include an ultra-orthodox Jewish circumcision practice known as metzitzah b'peh, the Christian common communion chalice, Islamic ritual ablution, and the Hindu 'side-roll'. Infections associated with participation in the Islamic Hajj have been extensively reviewed and will not be discussed.

Camel milk-associated infection risk perception and knowledge in French Hajj pilgrims

Cases of brucellosis have been recently reported in Hajj pilgrims following camel milk consumption. With the aim of evaluating French pilgrim's potential risk for raw camel milk-associated diseases, we conducted a knowledge, attitude, and practice study among 331 pilgrims departing to the 2011 Hajj. A proportion of 8.2% have drunk camel milk before, mostly in North Africa (62.9%) and Saudi Arabia (18.5%). A proportion of 13.9% declared they knew that drinking raw camel milk could cause diseases and 40.6% said that they would drink it if offered during the pilgrimage. Given that camel milk consumption in the Middle East is associated with several zoonotic infections in man, we recommend that Hajj pilgrims be cautioned against consuming unpasteurized dairy products.

The scaling of contact rates with population density for the infectious disease models

Contact rates and patterns among individuals in a geographic area drive transmission of directly-transmitted pathogens, making it essential to understand and estimate contacts for simulation of disease dynamics. Under the uniform mixing assumption, one of two mechanisms is typically used to describe the relation between contact rate and population density: density-dependent or frequency-dependent. Based on existing evidence of population threshold and human mobility patterns, we formulated a spatial contact model to describe the appropriate form of transmission with initial growth at low density and saturation at higher density. We show that the two mechanisms are extreme cases that do not capture real population movement across all scales. Empirical data of human and wildlife diseases indicate that a nonlinear function may work better when looking at the full spectrum of densities. This estimation can be applied to large areas with population mixing in general activities. For crowds with unusually large densities (e.g., transportation terminals, stadiums, or mass gatherings), the lack of organized social contact structure deviates the physical contacts towards a special case of the spatial contact model - the dynamics of kinetic gas molecule collision. In this case, an ideal gas model with van der Waals correction fits well; existing movement observation data and the contact rate between individuals is estimated using kinetic theory. A complete picture of contact rate scaling with population density may help clarify the definition of transmission rates in heterogeneous, large-scale spatial systems.

Infectious diseases in the Arabian Peninsula and Egypt

Infectious diseases are important causes of morbidity and mortality globally. Epidemiologically, differences in the patterns of infectious diseases and antimicrobial resistance exist across diverse geographical regions. In this review on infectious diseases in the Arabian Peninsula and Egypt, the epidemiology of tuberculosis, malaria and human immunodeficiency virus (HIV) infections will be addressed. The challenges of the hepatitis C epidemic in Egypt and the epidemiology of this infection across the region will be reviewed. In recent years, we have seen dengue endemicity become established, with major outbreaks in parts of the region. Emerging data also indicate that, across the region, there is an increasing burden of antibiotic resistance, with endemicity in healthcare settings and dissemination into the community. New challenges include the emergence of the Alkhurma haemorrhagic fever virus in Saudi Arabia. The annual Hajj pilgrimage in Saudi Arabia serves as a model for the control of infectious disease in mass gatherings. As most of these countries constantly experience a uniquely dynamic population influx in the form of expatriate workers, tourists, or pilgrims, concerted regional and international collaboration to address these public health concerns in a region that lies at the crossroads for the global spread of infectious pathogens is imperative.

Modeling rapidly disseminating infectious disease during mass gatherings

We discuss models for rapidly disseminating infectious diseases during mass gatherings (MGs), using influenza as a case study. Recent innovations in modeling and forecasting influenza transmission dynamics at local, regional, and global scales have made influenza a particularly attractive model scenario for MG. We discuss the behavioral, medical, and population factors for modeling MG disease transmission, review existing model formulations, and highlight key data and modeling gaps related to modeling MG disease transmission. We argue that the proposed improvements will help integrate infectious-disease models in MG health contingency plans in the near future, echoing modeling efforts that have helped shape influenza pandemic preparedness plans in recent years.

Participation in mass gatherings can benefit well-being: longitudinal and control data from a North Indian Hindu pilgrimage event

How does participation in a long-duration mass gathering (such as a pilgrimage event) impact well-being? There are good reasons to believe such collective events pose risks to health. There are risks associated with communicable diseases. Moreover, the physical conditions at such events (noise, crowding, harsh conditions) are often detrimental to well-being. Yet, at the same time, social psychological research suggests participation in group-related activities can impact well-being positively, and we therefore investigated if participating in a long-duration mass gathering can actually bring such benefits. In our research we studied one of the world's largest collective events - a demanding month-long Hindu religious festival in North India. Participants (comprising 416 pilgrims who attended the gathering for the whole month of its duration, and 127 controls who did not) completed measures of self-assessed well-being and symptoms of ill-health at two time points. The first was a month before the gathering commenced, the second was a month after it finished. We found that those participating in this collective event reported a longitudinal increase in well-being relative to those who did not participate. Our data therefore imply we should reconceptualise how mass gatherings impact individuals. Although such gatherings can entail significant health risks, the benefits for well-being also need recognition. Indeed, an exclusive focus on risk is misleading and limits our understanding of why such events may be so attractive. More importantly, as our research is longitudinal and includes a control group, our work adds robust evidence to the social psychological literature concerning the relationship between participation in social group activities and well-being.

Microbiological aspects of public health planning and preparedness for the 2012 Olympic Games

Although communicable diseases have hitherto played a small part in illness associated with Olympic Games, an outbreak of infection in a national team, Games venue or visiting spectators has the potential to disrupt a global sporting event and distract from the international celebration of athletic excellence. Preparation for hosting the Olympic Games includes implementation of early warning systems for detecting emerging infection problems. Ensuring capability for rapid microbiological diagnoses to inform situational risk assessments underpins the ability to dispel rumours. These are a prelude to control measures to minimize impact of any outbreak of infectious disease at a time of intense public scrutiny. Complex multidisciplinary teamwork combined with laboratory technical innovation and efficient information flows underlie the Health Protection Agency's preparation for the London 2012 Olympic and Paralympic Games. These will deliver durable legacies for clinical and public health microbiology, outbreak investigation and control in the coming years.

Research agenda for mass gatherings: a call to action

Public health research is essential for the development of effective policies and planning to address health security and risks associated with mass gatherings (MGs). Crucial research topics related to MGs and their effects on global health security are discussed in this review. The research agenda for MGs consists of a framework of five major public health research directions that address issues related to reducing the risk of public health emergencies during MGs; restricting the occurrence of non-communicable and communicable diseases; minimisation of the effect of public health events associated with MGs; optimisation of the medical services and treatment of diseases during MGs; and development and application of modern public health measures. Implementation of the proposed research topics would be expected to provide benefits over the medium to long term in planning for MGs.

Sexual health and the Rugby World Cup 2011: a cross-sectional study of sexual health clinics in New Zealand

Background We aimed to describe the characteristics of sexual health clinic (SHC) attendance and sexually transmissible infection (STI) diagnoses during the Rugby World Cup (RWC) in New Zealand in 2011. Methods: SHC attendance and STI diagnoses around the time of the RWC were compared with the 5 preceding years. A cross-sectional survey conducted at SHCs in four New Zealand cities collected information from attendees having RWC-related sex. Results: Although there was no statistically significant increase in clinic attendance or STI diagnoses during the RWC compared with previous years, in these four cities, 151 individuals of 2079 attending SHCs for a new concern reported RWC-related sex. The most frequently diagnosed STIs were chlamydial infection (Chlamydia trachomatis), genital warts and genital herpes. Most attendees (74%) who had RWC-related sex had consumed three or more alcoholic drinks; 22% had used a condom. Seven percent of women reported nonconsensual sex. RWC-related sex was associated with an increased risk of STI diagnoses in men: gonorrhoea (Neisseria gonorrhoeae): relative risk (RR) = 4.9 (95% confidence interval (CI): 2.1–11.4); nonspecific urethritis: RR = 2.8 (95% CI: 1.3–5.9); chlamydial infection: RR = 1.8 (95% CI: 1.1–2.9). Using a condom was associated with a reduced risk (RR = 0.3, 95% CI: 0.1–0.9) of diagnosis with any STI among those having RWC-related sex. Conclusions: These findings highlight issues that are amenable to prevention. The continued promotion of condoms as well as a reduction in the promotion and availability of alcohol at such events may reduce sexual health risks as well as other harm.