Guénaël Rodier

The Reemergence of Ebola Hemorrhagic Fever, Democratic Republic of the Congo, 1995

In May 1995, an international team characterized and contained an outbreak of Ebola hemorrhagic fever (EHF) in Kikwit, Democratic Republic of the Congo. Active surveillance was instituted using several methods, including house-to-house search, review of hospital and dispensary logs, interview of health care personnel, retrospective contact tracing, and direct follow-up of suspect cases. In the field, a clinical case was defined as fever and hemorrhagic signs, fever plus contact with a case-patient, or fever plus at least 3 of 10 symptoms. A total of 315 cases of EHF, with an 81% case fatality, were identified, excluding 10 clinical cases with negative laboratory results. The earliest documented case-patient had onset on 6 January, and the last case-patient died on 16 July. Eighty cases (25%) occurred among health care workers. Two individuals may have been the source of infection for >50 cases. The outbreak was terminated by the initiation of barrier-nursing techniques, health education efforts, and rapid identification of cases.

Hot spots in a wired world: WHO surveillance of emerging and re-emerging infectious diseases

The resurgence of the microbial threat, rooted in several recent trends, has increased the vulnerability of all nations to the risk of infectious diseases, whether newly emerging, well-established, or deliberately caused. Infectious disease intelligence, gleaned through sensitive surveillance, is the best defence. The epidemiological and laboratory techniques needed to detect, investigate, and contain a deliberate outbreak are the same as those used for natural outbreaks. In April 2000, WHO formalised an infrastructure (the Global Outbreak Alert and Response Network) for responding to the heightened need for early awareness of outbreaks and preparedness to respond. The Network, which unites 110 existing networks, is supported by several new mechanisms and a computer-driven tool for real time gathering of disease intelligence. The procedure for outbreak alert and response has four phases: systematic detection, outbreak verification, real time alerts, and rapid response. For response, the framework uses different strategies for combating known risks and unexpected events, and for improving both global and national preparedness. New forces at work in an electronically interconnected world are beginning to break down the traditional reluctance of countries to report outbreaks due to fear of the negative impact on trade and tourism. About 65% of the worlds first news about infectious disease events now comes from informal sources, including press reports and the internet.

Risk Factors for Marburg Hemorrhagic Fever, Democratic Republic of the Congo

We conducted two antibody surveys to assess risk factors for Marburg hemorrhagic fever in an area of confirmed Marburg virus transmission in the Democratic Republic of the Congo. Questionnaires were administered and serum samples tested for Marburg-specific antibodies by enzyme-linked immunosorbent assay. Fifteen (2%) of 912 participants in a general village cross-sectional antibody survey were positive for Marburg immunoglobulin G antibody. Thirteen (87%) of these 15 were men who worked in the local gold mines. Working as a miner (odds ratio [OR] 13.9, 95% confidence interval [CI] 3.1 to 62.1) and receiving injections (OR 7.4, 95% CI 1.6 to 33.2) were associated with a positive antibody result. All 103 participants in a targeted antibody survey of healthcare workers were antibody negative. Primary transmission of Marburg virus to humans likely occurred via exposure to a still unidentified reservoir in the local mines. Secondary transmission appears to be less common with Marburg virus than with Ebola virus, the other known filovirus.

Conceptual framework of public health surveillance and action and its application in health sector reform

BackgroundBecause both public health surveillance and action are crucial, the authors initiated meetings at regional and national levels to assess and reform surveillance and action systems. These meetings emphasized improved epidemic preparedness, epidemic response, and highlighted standardized assessment and reform.MethodsTo standardize assessments, the authors designed a conceptual framework for surveillance and action that categorized the framework into eight core and four support activities, measured with indicators.ResultsIn application, country-level reformers measure both the presence and performance of the six core activities comprising public health surveillance (detection, registration, reporting, confirmation, analyses, and feedback) and acute (epidemic-type) and planned (management-type) responses composing the two core activities of public health action. Four support activities – communications, supervision, training, and resource provision – enable these eight core processes. National, multiple systems can then be concurrently assessed at each level for effectiveness, technical efficiency, and cost.ConclusionsThis approach permits a cost analysis, highlights areas amenable to integration, and provides focused intervention. The final public health model becomes a district-focused, action-oriented integration of core and support activities with enhanced effectiveness, technical efficiency, and cost savings. This reform approach leads to sustained capacity development by an empowerment strategy defined as facilitated, process-oriented action steps transforming staff and the system.

Global public health security.

National public health institutes will play a key role in implementation of the revised International Health Regulations.

Ebola Hemorrhagic Fever: Lessons from Kikwit, Democratic Republic of the Congo

The outbreak of Ebola hemorrhagic fever in Kikwit, Democratic Republic of the Congo, clearly signaled an end to the days when physicians and researchers could work in relative obscurity on problems of international importance, and it provided many lessons to the international public health and scientific communities. In particular, the outbreak signaled a need for stronger infectious disease surveillance and control worldwide, for improved international preparedness to provide support when similar outbreaks occur, and for accommodating the needs of the press in providing valid information. A need for more broad-based international health regulations and electronic information systems within the World Health Organization also became evident, as did the realization that there are new and more diverse partners able to rapidly respond to international outbreaks. Finally, a need for continued and coordinated Ebola research was identified, especially as concerns development of simple and valid diagnostic tests, better patient management procedures, and identification of the natural reservoir.

Pandemic Influenza as 21st Century Urban Public Health Crisis

Responses of Mexico City and New York City in spring 2009 illustrate the importance of advance planning.

Exposure Patterns Driving Ebola Transmission in West Africa: A Retrospective Observational Study.

Background The ongoing West African Ebola epidemic began in December 2013 in Guinea, probably from a single zoonotic introduction. As a result of ineffective initial control efforts, an Ebola outbreak of unprecedented scale emerged. As of 4 May 2015, it had resulted in more than 19,000 probable and confirmed Ebola cases, mainly in Guinea (3,529), Liberia (5,343), and Sierra Leone (10,746). Here, we present analyses of data collected during the outbreak identifying drivers of transmission and highlighting areas where control could be improved. Methods and Findings Over 19,000 confirmed and probable Ebola cases were reported in West Africa by 4 May 2015. Individuals with confirmed or probable Ebola (“cases”) were asked if they had exposure to other potential Ebola cases (“potential source contacts”) in a funeral or non-funeral context prior to becoming ill. We performed retrospective analyses of a case line-list, collated from national databases of case investigation forms that have been reported to WHO. These analyses were initially performed to assist WHO’s response during the epidemic, and have been updated for publication. We analysed data from 3,529 cases in Guinea, 5,343 in Liberia, and 10,746 in Sierra Leone; exposures were reported by 33% of cases. The proportion of cases reporting a funeral exposure decreased over time. We found a positive correlation (r = 0.35, p < 0.001) between this proportion in a given district for a given month and the within-district transmission intensity, quantified by the estimated reproduction number (R). We also found a negative correlation (r = −0.37, p < 0.001) between R and the district proportion of hospitalised cases admitted within ≤4 days of symptom onset. These two proportions were not correlated, suggesting that reduced funeral attendance and faster hospitalisation independently influenced local transmission intensity. We were able to identify 14% of potential source contacts as cases in the case line-list. Linking cases to the contacts who potentially infected them provided information on the transmission network. This revealed a high degree of heterogeneity in inferred transmissions, with only 20% of cases accounting for at least 73% of new infections, a phenomenon often called super-spreading. Multivariable regression models allowed us to identify predictors of being named as a potential source contact. These were similar for funeral and non-funeral contacts: severe symptoms, death, non-hospitalisation, older age, and travelling prior to symptom onset. Non-funeral exposures were strongly peaked around the death of the contact. There was evidence that hospitalisation reduced but did not eliminate onward exposures. We found that Ebola treatment units were better than other health care facilities at preventing exposure from hospitalised and deceased individuals. The principal limitation of our analysis is limited data quality, with cases not being entered into the database, cases not reporting exposures, or data being entered incorrectly (especially dates, and possible misclassifications). Conclusions Achieving elimination of Ebola is challenging, partly because of super-spreading. Safe funeral practices and fast hospitalisation contributed to the containment of this Ebola epidemic. Continued real-time data capture, reporting, and analysis are vital to track transmission patterns, inform resource deployment, and thus hasten and maintain elimination of the virus from the human population.

Contact Tracing Activities during the Ebola Virus Disease Epidemic in Kindia and Faranah, Guinea, 2014.

Thorough case identification and contact tracing are necessary to end this epidemic.

Ebola vaccines: keep the clinical trial protocols on the shelf and ready to roll out

Safe and eff ective vaccines to prevent Ebola infection would be useful in the fi ght against this devastating disease. Depending on their effi cacy, onset of immunity, length of protection, and cost and ease of administration, these vaccines could contain or even prevent an outbreak. During an outbreak, a vaccine could prevent infection of front-line health workers and staff who are engaged in patient transport and burial. In terms of containment action, vaccination of whole households of patients could prevent any tertiary cases that might occur from persons infected secondarily by caring for the initial household case. Populations at high risk, eg, villages or urban wards where multiple transmission chains have been identifi ed, could also be targeted in a vaccination programme. Because exposure risk is time-limited in most outbreaks, these vaccination strategies might not need a vaccine that triggers long-lasting immunity. An Ebola vaccine that induces long-lasting immunity could, however, fi nd a place in outbreak prevention. Routine vaccination of health workers in areas where Ebola infection is known to be a risk within west and central Africa, could be a major intervention to prevent Ebola outbreaks. The majority of outbreaks, including the most recent outbreak in DR Congo in 2014, occurred after health workers became infected. Infected heath workers inadvertently serve as a conduit of infection to their own family members or caretakers, and from these initial infections, transmission is sustained in the community by direct contact with patients or dead bodies. Some evidence indicates that if Ebola emerges and its transmission is not amplifi ed by infection of health workers, outbreaks do not occur. More widespread preventive vaccination in general populations living in high-risk areas would depend on cost-benefi t analysis, operational feasibility, and acceptance. Previous Ebola vaccines have been developed with fi nancial aid of grants provided by various US defence and health agencies because of concern that the Ebola virus could be used deliberately for bioterrorism, but no public health call for such vaccines from WHO or other international organisations, African countries, or civil society was ever made prior to the current outbreaks. Although the Board of GAVI, the vaccine alliance, has approved plans of up to US