Hi, my name is Dr. Eric Mintz and I'm an epidemiologist at the CDC, the Centers for Disease Control and Prevention in Atlanta. Today, I'm going to talk to you about diarrheal diseases in complex humanitarian emergencies and how they can be prevented. A complex humanitarian emergency can occur when populations are subject to a natural disaster or to war, violent social upheaval or terrorism. People may be displaced or they may be trapped in place and they lack regular access to things we take for granted like water, food, shelter, and medical care. In these settings, the risk of epidemic infectious diseases is very high, unless measures are taken to detect them early and control them quickly. Diarrheal diseases, which might normally sicken only a few people, can spread quickly through an entire population and cause thousands of deaths. The starkest recent reminder of how deadly epidemic diarrheal diseases can be during a humanitarian emergency occurred in Goma, Zaire, in 1994. In just a few days, over half a million Rwandan refugees fleeing a violent civil war arrived in this remote area of Central Africa, in what is now known as the Democratic Republic of Congo, overwhelming the world's response capacity. During the first month, explosive epidemics of diarrheal disease caused by vibrio cholera 01, and shigella dysenteriae type 1, claimed the lives of almost 50,000 refugees, sickening and weakening tens of thousands of others. By the second month of the crisis a well coordinated relief program based on rapidly acquired health data and effective interventions was associated with a steep decline in deaths from nearly 1,500 per day to less tan 350 per day. In the emergency phase, during harsh conditions effective, low technology measure, including bucket chlorination at untreated water sources, designation of special defecation areas, active case finding through community outreach, and oral re-hydration, we're able to halt the epidemics of diarrheal disease and save many lives. The prompt provision of adequate quantities of disinfected water, basic sanitation, community outreach, and effective case management of ill patients, are key to the prevention and control of diarrheal diseases. And with timely and accurate surveillance data, and these simple measures, people like you can help ensure that the world's response capacity is never again overwhelmed, and that the nightmare experience of Goma is never repeated. Public health surveillance is the foundation of disease prevention and control. And nowhere is it more essential than in a complex humanitarian emergency. From a public health perspective, surveillance may be defined as the ongoing collection, analysis, and interpretation of health-related information with dissemination to those who need to know. Surveillance is an ongoing activity, not something static. And it involves not only the ongoing collection of health related information, but the ongoing analysis of that information, interpretation of that information, and dissemination of the results back to those who need to know. Because this is information for action. Actions like deciding how to allocate medical and financial resources for disease prevention and treatment in a complex, rapidly evolving emergency situation. Here's what you need to know to establish a surveillance system for diarrheal diseases in a complex humanitarian emergency. Surveillance can begin before the emergency by gathering information about the context, in which the emergency is likely to occur. Here are some things to look for before the response even begins. The affected population, what is their age distribution, nutritional status? What is the prevalence of HIV infection and what's the vaccine coverage? Diarrheal diseases, which ones has this population seen before the emergency occurs? Which ones are endemic? Which diarrheal diseases have cause epidemics in this population? And which pathogens are resistant to which antibiotics. The environment, what is the climate like? What is the seasonality of diarrheal diseases in this part of the world? What are coverage rates for improved water sources and for sanitation? And what are the baseline knowledge's, attitudes and practices in the population regarding water, sanitation, and hygiene and the use of oral re-hydration solution in antibiotics? All of this information can help create communications and educational materials and help choose effective prevention strategies that will be acceptable to the target community. Diarrheal disease surveillance is simple and it has a simple objective. You want to gather information on the time, place, and person that will allow you to monitor disease trends and detect suspected outbreaks early. In a complex humanitarian emergency, diarrheal disease outbreaks, especially those due to cholera or dysentery, can be explosive and you have to have daily reporting from health facilities and, or community outreach workers about the number of new cases of diarrhea and a special 24 hour hotline for reports of any suspected outbreaks. Because diarrheal disease outbreaks begin locally but spread globally. Surveillance should include representative coverage from populations in all areas through Sentinel health facilities in camps, and through data collected via local authorities outside of camps. Diarrheal diseases do not respect political boundaries, and outbreaks commonly occur on both sides of a given border, or inside or outside camps for displaced persons that are operated by different authorities. So collaborative cross-border and inter-agency surveillance is essential. Finally, with regards to person in addition to the number of cases that occur each day in each facility, it is very helpful to know how many cases occur in children less than 5 years old. And how many occur in people 5 years old or older. That's because different diarrheal diseases affect children and adults. And an increase in cases in only one or the other age group suggests a different diagnosis and a different treatment approach than an increase in cases in both age groups. Often the temptation is to try and collect too much information on each patient, their gender, ethnicity, occupation and risk factors such as their water source and their food sources. These data are useful for investigation such as case control studies. But if surveillance data is too complex or too time consuming to collect, busy health care providers and community health workers, will not have time for it. And the data gaps that that will create will undermine the entire surveillance system. Always remember the primary objective of surveillance in an emergency, is to monitor disease trends in real time. And detects suspected outbreaks as early as possible. This requires very little data but these data have to be consistently collected. That said, besides time, place, and person, data on clinical characteristics can be very helpful in monitoring diarrheal disease trends in providing clues for diagnosis and treatment needs. Every reported case of diarrhea should be characterized as either bloody diarrhea, the presence of visible blood, or the report of blood from the patient or the caretaker, or watery diarrhea. Associated symptoms such as vomiting, dehydration and fever are of some interest but are less essential. In some settings, it's possible to collect data on which patients are hospitalized, which is a measure of disease severity, that can help inform resource needs. Death is an outcome of diarrheal disease that is recognized in any situation, and is of critical importance for surveillance. Death from diarrhea indicates a failure to access appropriate treatment. When possible it is good to gather data on the deaths of patients by location, hospitalized or community deaths. A diarrheal death in the community indicates a problem with access to healthcare. And a diarrheal death in a health facility indicates a problems with quality of healthcare provided. Epidemiologic surveillance alone is not enough to prepare for in response to epidemics of diarrheal diseases. We also need the added support of laboratory diagnosis. Whenever an outbreak is suspected, laboratory testing can help identify the agent and point the way to appropriate treatment and prevention measures. Rapid diagnostic tests for cholera can be used in field conditions by staff with minimal training. Rapid test for typhoid fever and Shiga toxin producing bacteria, such as shigella dysenteriae type 1, are more complex but still useful for early outbreak investigation. Rapid tests should always be done in parallel with traditional stool culture. Which requires training, materials and equipment for specimen collection, and transport. And for the isolation identification and antimicrobial susceptibility testing of bacterial pathogens. Often these tests can be performed at the national reference laboratory or an external reference laboratory such as CDC or even a mobile field laboratory. Thank you. And for more information on diarrheal diseases, please visit the CDC website.
