Hello, my name is Susan Cookson. And I am an infectious diseases physician and the research coordinator at the Emergency Response and Recovery branch at the U.S. Centers for Disease Control and Prevention. Today I will be speaking to you about the importance of communicable diseases and complex humanitarian emergencies. I will begin with an overview of the burden of all communicable diseases and emergencies, and then talk about some overarching principles of communicable diseases in emergencies. In complex humanitarian emergencies, communicable disease epidemics are common, and the leading cause of death. This is because of lack of authority and security, lack of health and basic services, or, when the services exist, lack of access to them, or lack of access to the affected population for a variety of services. However, when we look at natural disasters, injuries are the leading cause of death. Communicable diseases are less common in natural disasters. However, depending on the size of the displaced population, and depending on their access to potable water and sanitation, you might see more communicable disease epidemics in this situation. So where do these data come from? Paul Spiegel et al looked at the 30 largest complex emergencies and natural disasters, determined by the mortality rate From 1995 to 2004. And found that communicable disease epidemics accounted for 63% of the 30 largest complex emergencies, but only 23% of the 30 largest natural disasters. So what are these communicable diseases? The answer comes from looking at past refugee populations in Somalia, Sudan, and Malawi. The leading cause of childhood mortality in these places were diarrheal diseases, causing up to 40% of the deaths in Somalia, acute respiratory infections at a solid 10%, and malaria, with the largest range from 2 to 25%. These are historical data without the push for measles vaccination early in the emergency. Measles mortality in one camp in Sudan was over 50%. In the last refugee group in Malawi, malnutrition, which can add to the severity and duration of communicable diseases, also was a leading cause of childhood death. In addition to these, which I call the big four, other diseases are re-emerging from old or previously controlled diseases, such as tuberculosis, or TB, guinea worm, and polio. Diseases that are also re-emerging with drug resistance due to incomplete use, or improper use, a broad-spectrum antibiotics. Again, we need to be thinking about TB, and of course, HIV, malaria, and common bacterial infections. There are also delays in detection, characterization, response, and containment of new pathogens, such as monkeypox in the DRC, coronavirus in the Middle East, and the recent spread of mosquito-borne, or arboviruses, like chikungunya and Zika. Widespread transmission can occur before controls are put into place, like the recent Ebola and yellow fever outbreaks, chikungunya and Zika worldwide, and outbreaks of hepatitis E in multiple places in East Africa. Driving these large burden of communicable diseases is the combination of risk factors that lead to increased transmission and heightened epidemic potential. These risk factors are similar to those faced in developing countries and include, poor access to health care or actual collapse of healthcare. A lack of prevention and control programs, resulting in low immunization coverage or lack of immunization. Lack of vector-borne control, such as mosquito control, lack of specific disease control programs, like TB, HIV, and lack of condoms and of medicines and supplies. Risk factors specific to humanitarian emergencies include absence or unstable governments, ongoing conflict and insecurity, and poor coordination among service providers when they are present. Additional factors in emergencies are mass population movement leading to overcrowding, environmental degradation, poor shelter provisions, increased gender based violence, and poor nutritional status due to the scarcity of food. These can all exacerbate communicable disease risk and humanitarian emergencies. So what can be done? The principles in emergency focus on the major causes of mortality. This means effective planning of camp sites that are near clean water supply, not near a swamp, and with good sanitation. These measures result in less overcrowding, to prevent acute respiratory diseases, diarrhea, and vector-borne diseases. A clean water supply also prevents additional water-borne diseases, such as Guinea worm, as well as vector-borne diseases that can thrive in just a small amount of water left from poor disposal methods. There should also be adequate nutrition to prevent all diseases that occur from destruction of the immune system, destruction of the mucous membrane, the gut, and the respiratory tract. Additional prevention measures include vaccination. Traditionally, in the acute phase of the emergency, just measles, or perhaps Polio vaccine, have been given. Once this phase is over, an expanded program on immunization, or EPI, should be reinstated as soon as possible. And include diphtheria, pertussis, polio, and in special outbreak situations, bacterial meningitis, or meningococcal disease, or yellow fever. Besides keeping the camp away from swamps, instating vector control programs as soon as possible is important for a large variety of diseases. Of course, educational programs are needed for hygiene promotion and health education with condom distribution. And finally, good case management of all diseases is imperative. To control epidemics and outbreaks, there is also a need to detect diseases as soon as they occur. This should be done by establishing an emergency communicable disease surveillance system as soon as possible. And only including diseases producing the greatest mortality and having the epidemic potential, i.e., my big four. Surveillance can quickly detect diseases or outbreaks so, then, outbreak control measures can be put into place, including well trained teams with sufficient supplies and logistics. A reference lab should be identified to confirm diseases, and all disease rumors should be investigated. Once the disease is confirmed, there should be steps to interrupt the transmission by treating cases, designing control measures to prevent further spread, and protecting susceptible groups. In summary, let's recall the most common diseases and emergencies. They are diarrheal disease, acute respiratory infections, measles, and malaria. Emerging and re-emerging diseases increasingly affect persons in conflict areas. And much of this excess morbidity and mortality is avoidable. Interventions are available, but they need to be more systematic and coordinated. And finally, more research is needed to identify evidence-based interventions, combat drug resistance, and develop short course in heat-stable vaccines. Thank you.