lunes, 27 de octubre de 2014

Ebola 2014 — New Challenges, New Global Response and Responsibility — NEJM

Ebola 2014 — New Challenges, New Global Response and Responsibility — NEJM


Ebola 2014 — New Challenges, New Global Response and Responsibility

Thomas R. Frieden, M.D., M.P.H., Inger Damon, M.D., Ph.D., Beth P. Bell, M.D., M.P.H., Thomas Kenyon, M.D., M.P.H., and Stuart Nichol, Ph.D.
N Engl J Med 2014; 371:1177-1180September 25, 2014DOI: 10.1056/NEJMp1409903
Citing Articles (7)
Since Ebola virus was first identified in 1976, no previous Ebola outbreak has been as large or persistent as the current epidemic, and none has spread beyond East and Central Africa.1 To date, more than 1000 people, including numerous health care workers, have been killed by Ebola virus disease (EVD) in 2014, and the number of cases in the current outbreak now exceeds the number from all previous outbreaks combined. Indirect effects include disruption of standard medical care, including for common and deadly conditions such as malaria, and substantial economic losses, insecurity, and social disruption in countries that were already struggling to recover from decades of war.
The outbreak's spread to densely populated Lagos, Nigeria, is worrisome, and the situation there is evolving rapidly. Lagos has a population roughly equivalent to that of Guinea, Sierra Leone, and Liberia combined, and it took nearly 2 weeks to establish the first effective isolation and treatment facilities there. Nigeria has since greatly improved its response, but whether it acted in time to stop a large outbreak is not yet clear. Given the extensive mobility and air travel in West Africa, EVD could reach other countries in the region and beyond. Every day that disease transmission remains uncontrolled, the likelihood of spread to unaffected countries increases.
The Centers for Disease Control and Prevention (CDC) is working intensively with partners to help stop the outbreak at its source in Africa. We are also assisting the four affected countries to improve their exit-screening protocols to help protect the rest of the world, including the United States. Each month, several thousand travelers from affected areas enter the United States, and even more people travel to and from Europe, other parts of Africa, and Asia. As long as Ebola is spreading in these regions, clinicians need to be alert to the possibility of EVD, take a travel history, and promptly isolate and test ill travelers who have returned from these regions in the past 21 days and have symptoms consistent with EVD. The CDC has issued detailed guidelines regarding identifying, isolating, diagnosing, and treating patients.2 There is also specific guidance for airline flight crews, cleaning personnel, and cargo personnel to minimize their risk of exposure.3
Stopping the outbreak at the source in Africa will take many months. Three core interventions have stopped every previous outbreak and can stop this one as well: exhaustive case and contact finding, effective response to patients and the community, and preventive interventions.
Identifying infected persons quickly requires accessible diagnostic and treatment facilities. In the current outbreak, the number of patients has far exceeded local capacity, which has resulted in a vicious cycle in which more cases lead to overloading of facilities which leads to more cases. Laboratory testing with real-time polymerase chain reaction is sensitive and specific and can return results within hours; it is now becoming more widely available in the affected areas.
Responding to cases involves isolation and treatment of patients, contact tracing, and monitoring each contact for 21 days after exposure. It is difficult to isolate and care for patients with EVD, not because the disease is particularly infectious or the virus particularly hardy, but because a single lapse can be devastating. Neither negative air flow nor special respirators are essential; meticulous attention to gown, glove, mask, and eye protection and great care while removing protective equipment are key. Improved hospital infection control throughout the region would prevent a substantial number of EVD and other illnesses. Soap and water or alcohol-based hand sanitizers readily disrupt the envelope of this single-stranded RNA virus, and decontamination with dilute bleach is effective and readily available even in remote settings.
Provision of supportive care, particularly fluid and electrolyte management and treatment of bacterial superinfections, can significantly improve survival. Contacts need to be identified and their temperature monitored daily for 21 days after exposure; if they develop fever, they will also need to be immediately isolated, tested, and if tests are positive, interviewed to identify contacts, each of whom must then be followed for 21 days. Social mobilization and culturally appropriate health education efforts are critical to successful case identification and tracking of contacts.
There are three key preventive interventions. The first is meticulous infection control in health care settings. The greatest risk of transmission is not from patients with diagnosed infection but from delayed detection and isolation. Since the early symptoms of EVD — fever, nausea, vomiting, diarrhea, and weakness — are nonspecific and common, patients may expose family caregivers, health care workers, and other patients before the infection is diagnosed.
Second, educating and supporting the community to modify long-standing local funeral practices to prevent contact with body fluids of people who have died from EVD, at least temporarily until the outbreak is controlled, will close the second major route of propagation of the virus. This is a culturally sensitive issue that requires culturally appropriate outreach and education.
And third, avoiding handling of bush meat (wild animals hunted for sustenance) and contact with bats (which may be the primary reservoir of Ebola virus) can reduce the risk of initial introduction of Ebola virus into humans. Bush meat consumption could be reduced through socioeconomic development that increases access to affordable protein sources. Where bush meat consumption continues, safer slaughter and handling can be encouraged. The potential effect of deforestation and other environmental changes on increasing human–bat contacts needs to be further studied and addressed.
These are straightforward interventions, but Ebola virus is a formidable enemy. If a single case is missed, a single contact becomes ill and isn't isolated, or a single lapse in infection control or funeral-practice safety occurs, another chain of transmission can start.
In addition to implementing stringent control efforts, we need to accelerate development and deployment of vaccines and antiviral treatment. Supportive medical care can reduce case fatality rates substantially (and probably contributed to the much lower — 23% — case fatality rate in the Marburg virus outbreak in Germany4), but there are promising antiviral treatments and vaccines currently in development.5 Ethical issues have been raised about using experimental treatments and vaccines that are in very limited supply, but a vaccine that is safe and effective would further protect health care workers and potentially others in outbreak situations. Phase 1 clinical trials are expected to begin in the coming weeks, and intensive discussions are under way regarding how to evaluate and provide these vaccine candidates, with informed consent, for pre- or post-exposure prophylaxis.
In addition to acting to stop this outbreak, we should put systems in place to prevent another one. Earlier this year, the United States joined partner governments, the World Health Organization, and other multilateral organizations and nongovernmental actors to launch the Global Health Security Agenda (see tableElements of the Global Health Security Agenda and Their Application to the Ebola Outbreak.), which aims to better protect all people from health threats. As the world faces the major threats of emerging or reemerging organisms, increased drug resistance, and the intentional or unintentional spread of virulent pathogens, we have three critical advances that will enable further action: increased societal commitment on a global scale; new technologies that allow us to work better, faster, and cheaper; and successes, ranging from better control of EVD in Uganda to the rapid and effective response to H7N9 influenza in China. The current EVD outbreak is a tragic illustration of the importance of improving global health security (see table). The components of this strategy — prevent wherever possible, detect rapidly, and respond effectively — match the framework for stopping the EVD outbreak.
EVD is a painful reminder that an outbreak anywhere can be a risk everywhere. The Global Health Security Agenda aims to strengthen public health systems in countries that need it most in order to stop outbreaks before they become emergencies. We believe that stopping outbreaks in a way that leaves behind stronger systems to identify, stop, and prevent future health threats is a moral imperative.

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