Outbreak Control Measures Research Articles

Economic value of norovirus outbreak control measures in healthcare settings

AbstractAlthough norovirus is a significant cause of nosocomial viral gastroenteritis, the economic value of hospital outbreak containment measures following identification of a norovirus case is currently unknown. We developed computer simulation models to determine the potential cost-savings from the hospital perspective of implementing the following norovirus outbreak control interventions: (i) increased hand hygiene measures, (ii) enhanced disinfection practices, (iii) patient isolation, (iv) use of protective apparel, (v) staff exclusion policies, and (vi) ward closure. Sensitivity analyses explored the impact of varying intervention efficacy, number of initial norovirus cases, the norovirus reproductive rate (R0), and room, ward size, and occupancy. Implementing increased hand hygiene, using protective apparel, staff exclusion policies or increased disinfection separately or in bundles provided net cost-savings, even when the intervention was only 10% effective in preventing further norovirus transmission. Patient isolation or ward closure was cost-saving only when transmission prevention efficacy was very high (≥90%), and their economic value decreased as the number of beds per room and the number of empty beds per ward increased. Increased hand hygiene, using protective apparel or increased disinfection practices separately or in bundles are the most cost-saving interventions for the control and containment of a norovirus outbreak.

Waterborne norovirus outbreak in a municipal drinking-water supply in Sweden

During Easter 2009, almost 200 people resident in a small Swedish village fell ill with gastrointestinal symptoms. We conducted a retrospective cohort study and a molecular investigation in order to identify the source of the outbreak. Residents living in households connected to the public water network were at an increased risk of developing disease (relative risk 4·80, 95% confidence interval 1·68-13·73) compared to those with no connection to the public network. Norovirus genotype GI.3 was identified in stool samples from six patients and in a sample from the public water network. Contamination of one of the wells supplying the public water network was thought to be the source of the outbreak. This is a description of a norovirus outbreak linked to a municipal drinking-water supply in Sweden. Information from epidemiological and molecular investigations is of utmost importance to guide outbreak control measures and to prevent future outbreaks.

Infección por virus pandémico (H1N1) 2009 en Andalucía

In April 2009, in response to the WHO's alert due to the existence of human infection cases with a new AH1N1 influenza virus, known as swine flu, Andalusian Health Authorities trigger an specific action plan. The surveillance actions developped provided us with appropriate clinical, epidemiological and virological characteristics of the disease. During the first few days, contingency plans were set up based on epidemiological surveillance and outbreak control measures were adopted through early alert and rapid response systems. After phase 6 was declared, influenza sentinel and severe cases surveillance were used in order to plan healthcare services, to reduce transmission and to identify and protect the most vulnerable population groups. Behaviour of pandemic influenza in Andalusia was similar to that observed in the rest of the world. Atack rate was similar to a seasonal flu and the peak was reached at the 46th/2009 week. Most of them were mild cases and affected particularly to young people. The average age of hospitalised patients was 32. Prior pulmonary disease, smoking and morbid obesity (BMI > 40) were the most common pathologies and risk factors in severe cases. An impact scenario of pandemic wave in Andalusia, with an expected attack rate from 2 to 5%, was prepared considering watt observed in the southern hemisphere. Characteristics of the epidemic concerning its extent, severity and mortality rate were adjusted to this scenario.

Advances in Rift Valley fever research: insights for disease prevention

The purpose was to review recent research on Rift Valley fever virus (RVFV) infection, encompassing four main areas: epidemiology and outbreak prediction, viral pathogenesis, human diagnostics and therapeutics, and vaccine and therapeutic candidates. RVFV continues to extend its range in Africa and the Middle East. Better definition of RVFV-related clinical syndromes and human risk factors for severe disease, combined with early-warning systems based on remote-sensing, simplified rapid diagnostics, and tele-epidemiology, hold promise for earlier deployment of effective outbreak control measures. Advances in understanding of viral replication pathways and host cell-related pathogenesis suggest means for antiviral therapeutics and for more effective vaccination strategies based on genetically engineered virus strains or subunit vaccines. RVFV is a significant health and economic burden in many areas of Africa, and remains a serious threat to other parts of the world. Development of more effective methods for RVFV outbreak prevention and control remains a global health priority.

Estudio de un brote poblacional de hepatitis A. Efectividad de la vacunación como medida de control

Objective To describe an outbreak of hepatitis A in the city of Albacete (Spain) and to assess the effectiveness of the control measures implemented. Methods When the outbreak was noted, definitions of a case were established. Clinical and epidemiological data were collected through a survey. The temporal-spatial distribution was identified through mapping and the epidemic curve. Health education and immunoglobulin (IG) administration were conducted as immediate prevention and control measures in the population at risk. Results From January 2005 to January 2006, 62 cases were reported. The most affected age groups were school children and young adults. Transmission was person to person. The epidemic curve was divided into two periods. Initial control measures consisted of hygiene measures and IG administration to contacts. In the second period, these measures were complemented with vaccination against hepatitis A in students of the school centers of the two neighborhoods initially involved. Due to public alarm and spread of the outbreak to adjacent neighborhoods, vaccination was extended to schools close to those where cases had been detected. No cases were notified after the last vaccination in January 2006. Conclusions The use of vaccination after exposure to the hepatitis A virus in young adults and the school population seems to be an effective outbreak control measure.

Novel Influenza A (H1N1) Outbreak at the U.S. Air Force Academy: Epidemiology and Viral Shedding Duration

The U.S. Air Force Academy is an undergraduate institution that educates and trains cadets for military service. Following the arrival of 1376 basic cadet trainees in June 2009, surveillance revealed an increase in cadets presenting with respiratory illness. Specimens from ill cadets tested positive for novel influenza A (H1N1 [nH1N1])-specific ribonucleic acid (RNA) by real-time reverse transcriptase-polymerase chain reaction. The outbreak epidemiology, control measures, and nH1N1 shedding duration are described. Case patients were identified through retrospective and prospective surveillance. Symptoms, signs, and illness duration were documented. Nasal-wash specimens were tested for nH1N1-specific RNA. Serial samples from a subset of 53 patients were assessed for presence of viable virus by viral culture. A total of 134 confirmed and 33 suspected cases of nH1N1 infection were identified with onset date June 25-July 24, 2009. Median age of case patients was 18 years (range, 17-24 years). Fever, cough, and sore throat were the most commonly reported symptoms. The incidence rate among basic cadet trainees during the outbreak period was 11%. Twenty-nine percent (31/106) of samples from patients with temperature <100 degrees F and 19% (11/58) of samples from patients reporting no symptoms for > or = 24 hours contained viable nH1N1 virus. Of 29 samples obtained 7 days from illness onset, seven (24%) contained viable nH1N1 virus. In the nH1N1 outbreak under study, the number of cases peaked 48 hours after a social event and rapidly declined thereafter. Almost one quarter of samples obtained 7 days from illness onset contained viable nH1N1 virus. These data may be useful for future investigations and in scenario planning.

Costing Infectious Disease Outbreaks for Economic Evaluation

With the aim to understand and estimate the economic impact of outbreaks of community-acquired infections, we performed a review focusing on hepatitis A outbreaks, and retained 13 papers that had collected relevant cost information during such outbreaks. All costs in this article are expressed in USD, year 2007 values. The costs of hepatitis A outbreaks ranged from USD140 000 to US36 million, and the costs per case in an outbreak situation ranged from USD3824 to USD200 480. These costs were typically found to be substantially higher than estimates from cost-of-illness studies (i.e. costs for sporadic cases) and estimates used in cost-effectiveness analyses, mostly because of costly outbreak-control measures. Post-exposure prophylaxis is a major cost factor, especially for food-borne outbreaks. As a result of the increasing proportion of those susceptible to hepatitis A in low-incidence countries, future outbreaks could, on average, increase in size. The increasing occurrence of hepatitis A cases in outbreak situations and the associated control costs should appropriately be accounted for in economic evaluations of vaccination programmes in low-incidence countries. In order to do this, more studies documenting such outbreak-control strategies in terms of costs and resource use are needed.

Development and Implementation of a Functional Exercise to Assess Public Health Agency Response to Foodborne Bioterrorism

Agroterrorism and food terrorism have been identified as important homeland security issues by officials in the public health, government, and food industry sectors of the U.S. Intentional contamination of food has already occurred both abroad and in North America. Outbreak investigation and control measures in response to intentional contamination differ from those employed in cases of naturally occurring contamination. Operations-based exercise efforts specific to bioterrorism events are essential to train public health personnel and first responders to consider the possibility of deliberate contamination during an outbreak investigation. A recent search of the Rand Corporation's Public Health Preparedness database identified no operations-based (functional or full-scale) exercises involving foodborne contamination with a biological or chemical agent.This manuscript describes a functional exercise developed and conducted by the University of Illinois, College of Veterinary Medicine, Section of Community Health and Preventive Medicine. The functional exercise simulated a food-borne terrorism event and was designed to evaluate the efficacy of the Food Emergency Response Plan (FERP) of the Illinois Department of Public Health (IDPH), Division of Food, Drugs and Dairies (DFDD). The exercise was held on November 18th and 19th, 2008 at the College of Veterinary Medicine, University of Illinois, Urbana, IL.Based on this and previous exercises and training programs developed and conducted by CHPM, it is apparent that the more exercise designers, evaluators and public health and support agency participants move away from discussion based exercises and towards operations based exercises, the more strengths and deficiencies in preparation and response of participating agencies are revealed. Although public health agencies have begun training personnel and partner agencies to consider intentional contamination of food during an outbreak investigation, the relative lack of widespread operations-based exercises to assess preparedness in response to an intentional incident of food-borne contamination seems to be an important deficiency in homeland security. Additional funding to create opportunities for public health and first responder personnel to participate in operations-based bioterrorism response exercises is needed.

Measles outbreak in Qassim, Saudi Arabia 2007: epidemiology and evaluation of outbreak response

Worldwide efforts for measles elimination are made possible due to the availability of a highly effective measles vaccine. In spite of highly vaccinated population, a measles outbreak occurred in Qassim province of Saudi Arabia, during January-August 2007. An outbreak investigation was conducted to describe the epidemiology of outbreak. An audit of performance of control measures taken by the Primary Health Care team was done according to World Health Organization standards. Of 230 cases reported, more than one-third (37.8%) patients were 0-4 years of age. Children aged 6-11 months accounted for 51.7% cases amongst 0-4 years age group. The performance indicator targets of >or=80% for outbreak control measures were achieved regarding investigation of cases within 48 hours, and blood sample extraction within the optimal period. However, 66.8% cases reported within 48 hours of rash onset and only 16.4% of laboratory test results were received within 7 days of receipt of the specimen in laboratory. This outbreak demonstrates the increased susceptibility of unvaccinated children aged 6-11 months. To prevent future outbreaks, community awareness, review of measles vaccination schedule, enhanced surveillance and measles 'catch-up' mass immunization campaign to interrupt chains of transmission, are required.

Screening Policies for Daycare Attendees

Control measures for enteric outbreaks in child care settings frequently include screening by stool cultures from symptomatic children only. We present evidence from an investigation of Escherichia coli (E. coli) O157:H7 in a daycare in Waterloo, Ontario to support implementation of a mandatory screening policy for all children during an outbreak. In addition to routine outbreak control measures employed by the health unit, stool samples from all children and staff were collected, with positive E. coli cultures typed by pulsed field gel electrophoresis (PFGE). We conducted a cohort study, using data from the environmental investigation and questionnaires administered to parents and staff, to look for risk factors for infection and to survey parent/staff knowledge regarding appropriate management of diarrhea. Overall 11 E. coli O157:H7 cases were identified (7 lab-confirmed); 9 were children. No common source of infection was identified. Factors identified as possibly contributing to person-to-person transmission within the daycare included: i) the underreporting and possible attendance of symptomatic children despite alerting parents to the outbreak and requirements to keep symptomatic children at home, ii) possible transmission from an asymptomatic infected child, and iii) inconsistent understanding among parents and staff regarding diarrhea and appropriate management of a child with diarrhea. This investigation reveals that in child care settings, E. coli O157:H7 outbreak screening policies based on reported symptoms only may be insufficient. We recommend that such policies be amended to include the collection of at least one stool culture from all children in attendance, regardless of symptom history.

Screening policies for daycare attendees: lessons learned from an outbreak of E. coli O157:H7 in a daycare in Waterloo, Ontario.

Control measures for enteric outbreaks in child care settings frequently include screening by stool cultures from symptomatic children only. We present evidence from an investigation of Escherichia coli (E. coli) O157:H7 in a daycare in Waterloo, Ontario to support implementation of a mandatory screening policy for all children during an outbreak. In addition to routine outbreak control measures employed by the health unit, stool samples from all children and staff were collected, with positive E. coli cultures typed by pulsed field gel electrophoresis (PFGE). We conducted a cohort study, using data from the environmental investigation and questionnaires administered to parents and staff, to look for risk factors for infection and to survey parent/staff knowledge regarding appropriate management of diarrhea. Overall 11 E. coli O157:H7 cases were identified (7 lab-confirmed); 9 were children. No common source of infection was identified. Factors identified as possibly contributing to person-to-person transmission within the daycare included: i) the underreporting and possible attendance of symptomatic children despite alerting parents to the outbreak and requirements to keep symptomatic children at home, ii) possible transmission from an asymptomatic infected child, and iii) inconsistent understanding among parents and staff regarding diarrhea and appropriate management of a child with diarrhea. This investigation reveals that in child care settings, E. coli O157:H7 outbreak screening policies based on reported symptoms only may be insufficient. We recommend that such policies be amended to include the collection of at least one stool culture from all children in attendance, regardless of symptom history.

Working with symptoms of a respiratory infection: Staff who care for high-risk individuals

While many health care workers (HCWs) who have respiratory infections take sick leave, others work following illness onset. Little is known about attendance practices of HCWs caring for persons with spinal cord injuries (SCI), a group at high risk for respiratory complications. Cross-sectional survey of HCWs. Logistic regression identified factors associated with having a respiratory infection and examined if awareness of facility level institutional control measures and/or individual level factors influenced working while symptomatic. Response rate was 53% (n = 820). Respiratory infections were reported by 36%; of those, 86% attended work while symptomatic. HCWs aged 50 and above were less likely (odds ratio [OR] 0.58, P = 0.003) and those with a chronic condition were more likely (OR 2.24, P < 0.000) to have had a respiratory infection. HCWs who indicated that their facility institutes droplet precautions (OR 0.42, P = 0.034), restricts staff movement between wards, (OR 0.26, P = 0.002), and restricts contact between patients (OR 0.32, P = 0.009) were significantly less likely to work while symptomatic. It is alarming that 86% of HCWs attended work while symptomatic, given the consequences that respiratory infection can have on persons with SCI. HCW awareness of outbreak control measures within their facilities appeared to influence their attendance decisions, suggesting the importance of policy placement and information dissemination.

A National Outbreak of Ralstonia mannitolilytica Associated With Use of a Contaminated Oxygen-Delivery Device Among Pediatric Patients

In August 2005, the Centers for Disease Control and Prevention was notified of a Ralstonia species outbreak among pediatric patients receiving supplemental oxygen therapy with the Vapotherm 2000i (Vapotherm, Inc, Stevensville, MD). The Vapotherm 2000i is a reusable medical device that was used in >900 hospitals in the United States in 2005. Ralstonia are waterborne bacilli that have been implicated in hospital-acquired infections. We initiated an investigation to determine the source of the outbreak and implement infection control and prevention measures. We performed a case-control study at 1 hospital and conducted national case findings to obtain clinical and environmental samples for laboratory analysis. Case-patients had health care-acquired Ralstonia colonization or infection. Isolates were compared by using pulsed-field gel electrophoresis. We tested manufacturer-recommended disinfection protocols for the Vapotherm 2000i under simulated-use conditions. Case-patients at the hospital (n = 5) were more likely to have received Vapotherm therapy than controls. Nationally, Ralstonia mannitolilytica was confirmed in 38 patients (aged 5 days to 7 years); 35 (92%) of the patients were exposed to the Vapotherm 2000i before recovery of the organism. Pulsed-field gel electrophoresis showed related R. mannitolilytica strains from isolates sent from 18 hospitals in 12 states. A Vapotherm machine reprocessed with a protocol proposed by the manufacturer grew Ralstonia spp after 7 days of simulated use. In December 2005, Vapotherm recalled the 2000i. Our findings suggest intrinsic contamination of Vapotherm devices with Ralstonia spp. New medical devices may provide therapy equivalent to current devices yet pose novel reprocessing challenges.

Outbreak of Escherichia coli O157:H7 Infections Associated with Consumption of Beef Donair

The Calgary Health Region identified an outbreak of Escherichia coli O157:H7 infection in September 2004 following a fourfold increase in laboratory reports. Clinical isolates were indistinguishable by pulsed-field gel electrophoresis (PFGE), and the PFGE pattern was unique in North America. Most affected individuals reported beef donair consumption in 10-day food histories. We conducted a matched case-control study, inspected the implicated food premises, and conducted a traceback investigation of suspect ground beef to determine the source of the outbreak and implement prevention and control measures. A total of 43 laboratory-confirmed cases were identified, with symptom onsets between 8 September and 1 October 2004. Among 26 matched case-control pairs, consumption of beef donair from one of two locations of a local restaurant chain was the only statistically significant risk factor for infection (matched odds ratio undefined; P < 0.01). No samples of the implicated ground beef were available for microbiological testing. We identified several opportunities for time-temperature abuse and other factors that may have contributed to the serving of unsafe donair meat at the implicated restaurants. This outbreak highlighted gaps in food safety policy related to beef donair and similar products in Canada. Immediately following the outbreak, the Region implemented new safe food handling requirements and a Federal/Provincial/Territorial Working Group was established to make recommendations for national food safety policies specific to these products.

An Outbreak of Serratia marcescens Bacteremia Traced to Contamination of Intravenous Magnesium Sulfate Solution

BACKGROUND/OBJECTIVES: Previous outbreaks of <i>Serratia marcescens</i> (SM) have been associated with contaminated medical equipment, IV fluids and inadequate hand hygiene. In March 2005, the New Jersey Department of Health was notified of a cluster of SM bloodstream infections (BSIs). We investigated to determine the source of the outbreak and implement control measures. METHODS: We defined cases as SM BSI with onset date after January 2005. Medical records of cases were reviewed to identify risk factors for SM BSI. Medical equipment, medications, IV solutions, tap water and the hands of health care workers were tested for the presence of SM. SM isolates recovered from patients and environmental sampling were submitted to CDC for analysis by pulsed-field gel electrophoresis (PFGE). RESULTS: Five cases, with range of illness onset from March 2-10, 2005 were identified. Of these, three were men. Median age was 75 years (range: 17-79). All case-patients were admitted for cardiovascular surgery (CS) and had received IV magnesium sulfate (MS) less than 48 hours before sepsis onset. SM was isolated from a bag of MS solution administered to one patient and from an unopened MS solution bag; both bags were supplied premixed from the same company and had identical lot numbers. SM isolates from the five patients and the two bags of MS had identical PFGE patterns. After the use of premixed MS solutions from the implicated company was discontinued, no further SM BSIs were identified. CONCLUSIONS: Contaminated MS solutions caused this outbreak of SM BSI among CS patients. This led to a multi-state investigation of similar outbreaks and eventual recall of a nationally distributed product. Infection control professionals should consider exposure to intrinsically contaminated parenteral solutions in unusual clusters of hospitalized patients who develop BSI.

Measures to Control an Outbreak of Pertussis in a Neonatal Intermediate Care Nursery After Exposure to a Healthcare Worker

Hospitalized premature infants are particularly vulnerable to morbidity and mortality from pertussis. Effective prevention and investigative and control measures are not well described. To identify the source of nosocomial pertussis in a 2-month-old premature infant in a neonatal intermediate care nursery (ICN) and to critically review the investigation and outbreak control measures. An ICN and a neonatal intensive care unit. We queried healthcare workers (HCWs) and family members about cough illness and contacted potentially exposed patients to determine whether they had symptoms of pertussis. Culture and polymerase chain reaction (PCR) testing for Bordetella pertussis were performed by the hospital laboratory with specimens collected from symptomatic patients and HCWs. Levels of pertussis toxin immunoglobulin G antibodies were measured in HCWs with cough of at least 14 days' duration at a public health laboratory. Extensive control measures were instituted. Four ICN HCWs met the clinical case definition for presence of pertussis. Serologic test results were positive for 3 of the HCWs. The primary case patient was a 36-year-old HCW with a cough illness of 3-weeks' duration that was accompanied by paroxysms, whoop, posttussive emesis, and pneumothorax. Among the 4 affected HCWs, the duration of cough illness prior to identification of the infant index patient ranged from 11 to 25 days. Outbreak control measures included isolation of the infant case patient, furlough and treatment of symptomatic HCWs, administration of chemoprophylaxis to contacts, and surveillance for additional cases. Seventy-two infant patients and 72 HCWs were exposed and were given antibiotic prophylaxis. One additional case of pertussis, confirmed by PCR and culture, occurred in a resident physician who declined prophylaxis; she had cared for the index patient but had no contact with symptomatic HCWs. HCWs or patients may serve as the source of pertussis in nosocomial outbreaks, which can result in substantial morbidity and outlay of resources for control measures. Our review suggested that a diagnosis of pertussis should be an early consideration for HCWs with cough illness. Targeted pertussis immunization of HCWs, employee health policies that provide for testing and furlough of HCWs with prolonged cough, and monitoring of HCWs for compliance with infection control measures could reduce the morbidity and costs associated with pertussis outbreaks. These measures will require evaluation of their effectiveness.

Study design to determine the effects of widespread restrictions on hospital utilization to control an outbreak of SARS in Toronto, Canada

CONTEXT: Efforts to control an outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada, led to the imposition of major restrictions on nonurgent use of hospital-based services. OBJECTIVE: To describe a methodology to determine the impact of the restrictions on healthcare utilization. DESIGN, SETTING, POPULATION: Population-based study of the Greater Toronto area and unaffected comparator regions, before, during and after the SARS outbreak (April 2001 to March 2004). OUTCOME MEASURES: Population-based rates of hospital admissions, emergency department and outpatient visits, inter-hospital transfers, diagnostic testing and essential drug prescribing, adjusted for age and sex. METHODS: We will assess the temporal patterns of healthcare utilization rates before, during and after the SARS restrictions in different regions using administrative health databases and longitudinal data analysis methods (generalized estimating equations). We will also use longitudinal cohort models to assess the effects of the restrictions to outcomes in cohorts diagnosed with specific chronic diseases. CONCLUSION: We will document the extent to which utilization of healthcare services decreased during the SARS epidemic and identify clinical problem areas where SARS-related restrictions had adverse consequences on health. This work will have planning implications for future outbreaks of SARS or other infectious diseases. Understanding how the outbreak control measures affected use of health services and ultimately the health of the population, is an important part of understanding the impact of SARS restrictions.

One Dose of Varicella Vaccine Does Not Prevent School Outbreaks: Is it Time for a Second Dose?

One Dose of Varicella Vaccine Does Not Prevent School Outbreaks: Is it Time for a Second Dose?

The Outbreak of SARS at Tan Tock Seng Hospital – Relating Epidemiology to Control

The outbreak of severe acute respiratory syndrome (SARS) began after the index case was admitted on 1 March 2003. We profile the cases suspected to have acquired the infection in Tan Tock Seng Hospital (TTSH), focussing on major transmission foci, and also describe and discuss the impact of our outbreak control measures. Using the World Health Organization (WHO) case definitions for probable SARS adapted to the local context, we studied all cases documented to have passed through TTSH less than 10 days prior to the onset of fever. Key data were collected in liaison with clinicians and through a team of onsite epidemiologists. There were 105 secondary cases in TTSH. Healthcare staff (57.1%) formed the majority, followed by visitors (30.5%) and inpatients (12.4%). The earliest case had onset of fever on 4 March 2003, and the last case, on 5 April 2003. Eighty-nine per cent had exposures to 7 wards which had cases of SARS that were not isolated on admission. In 3 of these wards, major outbreaks resulted, each with more than 20 secondary cases. Attack rates amongst ward-based staff ranged from 0% to 32.5%. Of 13 inpatients infected, only 4 (30.8%) had been in the same room or cubicle as the index case for the ward. The outbreak of SARS at TTSH showed the challenges of dealing with an emerging infectious disease with efficient nosocomial spread. Super-spreading events and initial delays in outbreak response led to widespread dissemination of the outbreak to multiple wards.

OIE/FAO International Scientific Conference on Avian Influenza

Since 1997 the community has witnessed a strain of highly pathogenic H5N1 avian influenza virus emerge and spread at an unprecedented rate. It has had devastating consequences for domestic poultry, wild avian species, and humans on 3 continents; 240 human cases have occurred with 141 deaths. From 1999 to 2003, poultry outbreak control measures in the European Union alone resulted in the depopulation of 50 million birds at a substantial cost to the global economy. Because of the ongoing human and animal infections, the public health and veterinary communities have recognized the urgent need for an ongoing collaborative and participatory approach to prevention and control of highly pathogenic avian influenza (HPAI). This monograph contains the proceedings of the International Scientific Conference on Avian Influenza held in Paris, France, in April 2005. The conference was sponsored by the World Organization for Animal Health (OIE) and the Food and Agriculture Organization (FAO), in collaboration with the World Health Organization (WHO). To address the emerging animal health crisis and mitigate risks to human health, at the outset of the HPAI H5N1 outbreaks in Southeast Asia in early 2004, these organizations held joint meetings in Rome (February 2004), followed by 2 regional meetings in Bangkok (February 2004) and Ho Chi Minh City (February 2005) to issue guidelines and recommendations for prevention and control. Because it appears that this HPAI H5N1 epizootic will persist for some time, the Paris 2005 meeting was held to achieve consensus on the most current strategies for long-term prevention and control, including poultry vaccination when appropriate. Bernard Vallat, the director general of the OIE, opened the meeting and urged scientists and regulators to consider strengthening farm biosecurity measures; to assess the role of ducks as a reservoir for avian influenza; to evaluate animal vaccination strategies; and to promote strengthening of veterinary services to enable better detection, surveillance, and response as an international public good. This meeting marked the official launching of the OIE/FAO Network (OFFLU), a network of avian influenza reference laboratories created to promote research on avian influenza, provide technical assistance to developing countries on diagnosis and management, and serve as a mechanism to interface with the WHO Influenza Network to obtain virus isolates from animals that can be used to produce vaccines to prevent a human pandemic. Opening remarks were made by Ilaria Capua, director of OIE and the National Reference Laboratory for Newcastle Disease and Avian Influenza in Padua, Italy. Dr. Capua called on the veterinary scientific community to take the following actions to limit the spread of the outbreaks: 1) expand understanding of the role of waterfowl and other nongallinaceous birds in the ecoepidemiology of HPAI, 2) further define the role of poultry vaccination in reducing the spread of infection and promoting animal welfare, 3) educate workers about prevention of exposure to avian influenza, and 4) conduct studies to address food safety concerns. More than 300 internationally renowned scientists with expertise in avian influenza attended the meeting, which featured sessions on ecology and epidemiology, pathogenesis, human health implications, diagnostics, control strategies including vaccination, and improvement of management tools. Highlights of the scientific recommendations generated include an emphasis on global sharing of viral isolates, research on epidemiology of wild birds, research on mechanisms of transfer between wild and domestic avian species, and research on pathogenesis in other farmed birds to clarify their role as intermediate hosts. The scientists concluded that the following elements were critical for achieving long-term control of HPAI infections in animals and humans: monitoring viruses for antigenic changes in virulence, performing surveillance of H9N2 viruses with the potential to infect mammals, and conducting epidemiologic studies at the human-animal interface by the OIE/FAO and the WHO networks of reference laboratories. This monograph contains the full text of the introductory speeches and manuscripts upon which the invited talks and abstracts of the poster sessions were based. It is an excellent reference for anyone interested in understanding the challenges the public health and veterinary community are facing due to the rapid emergence and complex ecoepidemiology of a viral pathogen that represents a major threat to public health and animal well-being.