When an emergency or crisis occurs, the public health system is often disrupted or destroyed. If the emergency is in a resource-poor area, the local public health system may have been ineffective or even nonexistent before the event. During the emergency response, where the aim is to prevent deaths related to the disaster, the first priority is the provision of basic medical care while re-establishing public health services (safe water and sanitation, disease surveillance and response, immunizations, etc.). If the situation is an earthquake or conflict emergency, a significant need for trauma care may exist. Positions on the DART can be filled as needed to deal with trauma care situations.
The level of health care provided will be determined by the condition of the affected population and the available resources. This level will be partially guided by the diseases endemic to the area and those that cause the greatest morbidity and mortality. Many of these diseases are discussed later in this section with guidance provided for their prevention and treatment. In theory, the emphasis of the health services should be on prevention, as the staff and other resources needed for treatment may not be adequate. Once morbidity rates are stabilized, the level of health care provided can be more comprehensive. Health care, however, should be appropriate for the local population and at a level that can be maintained. Services and levels of care should strive to adhere to international guidelines such as the Sphere standards. Guidance for the provision of health services and staffing is found later in this section.
2. Background Information for Initial Health Assessments
People with field experience and an understanding of epidemiology usually conduct the initial assessment (also called a rapid health assessment) as part of a multidisciplinary team. The purpose of the following section is to provide OFDA Assessment Team or DART members a basic understanding of some common epidemiological terms and how to calculate rates for the presence of diseases commonly found when doing rapid health assessments. This section also includes definitions for the two epidemiological concepts that form the core of science-based disaster response: mortality rate and morbidity rate. The intent is not to teach team members how to conduct epidemiological surveys, but rather to help them understand and evaluate data from surveys they may encounter in the field.
a. Epidemiologic Concepts
Epidemiology is the study of the occurrence, distribution, and determinants of diseases and injuries in human populations. An epidemiologist is concerned with the types and frequencies of illnesses, injuries, and other health-related conditions within a given population, and the factors that influence their distribution. The overall goal of the epidemiologist’s work is to discover the factors essential for diseases to occur within groups and then to find the best methods to reduce or prevent those factors and other conditions detrimental to the health of communities.
b. Epidemiologic Definitions
Endemic. The constant presence and/or usual presence of a disease or condition found in a population within a geographic area. This may also be thought of as the baseline.
Epidemic. The increase of cases of a disease, often occurring suddenly, than what would be expected for that population in that area or at that time. Even one or two cases of certain diseases (such as cholera) can be considered an epidemic. In other circumstances, an epidemic is defined by where the cases occur (e.g., West Nile virus in the United States) or when the cases occur (e.g., influenza in the summer).
Outbreak. Has the same definition as epidemic but is often used for a more limited geographic area.
SOME WORDS OF CAUTION:
Both terms, epidemic and outbreak, are often used interchangeably by epidemiologists. Some, however, consider outbreak to refer to a more localized situation, while epidemic is used to describe a more widespread and perhaps more prolonged occurrence. Because the word epidemic can be provocative, try to avoid using it when in the field, and use outbreak instead (refer to the "Prevention and Control of Infectious Diseases" section for the outbreak thresholds for specific disease).
Latency Period. The time between first contact with a noninfectious agent (cold, heat, radiation, poisons, toxins, etc.) and when symptoms appear. If the agent is infectious (bacteria, virus, parasite, etc.) the latency period is called the incubation period. Epidemiologists often calculate the average incubation period for a group and then look back in time to see when exposure to the agent could have occurred.
Incidence. A measure of the frequency with which an event, such as a new case of illness, occurs in a population over a period of time. New cases of a disease can occur either through onset of the disease in current members of the population or by immigration into the population of persons already ill. The formula for determining incidence rates is:
Incidence Rate =
((Number of new cases of a disease during a specified period of time)
/(Number of persons at risk of developing the disease during that period))
Prevalence. The proportion of a population with an illness or condition (both new and pre-existing cases). This may be a point in time (a point prevalence) or a period of time (a period prevalence). The formula for prevalence is:
((Total number of cases of a disease (old and new) )/
(Number of persons at risk of developing the disease))
The major distinction between prevalence and incidenceis that incidence is the frequency of the appearance of disease and prevalence is the percentage of the population with the disease.
Remember that both incidence and prevalence may be expressed as per 100 (102), 1,000 (103), or 10,000 (104). The value of n in the above equations depends on the relative frequency of a given disease. Also note that incidence is always expressed as a rate (meaning that it includes the concept of time), whereas prevalence may be expressed as a rate or as a simple proportion. For prevalence and incidence measurements to be useful, they must use the precise definition, and the time periods must be clearly designated.
c. Mortality and Morbidity Rates
Mortality rates and morbidity rates are two specific types of epidemiologic measures. They are discussed separately because of their importance and distinction in the disaster setting.
(1) Mortality Rate
The mortality rate (death rate) is the single most important indicator of serious stress (e.g., illness, malnutrition) in an affected population.
The crude mortality rate (CMR) is number of deaths in a population per 10,000 persons per day.
In well-run relief efforts, the overall CMR should not exceed twice that of the host population before the emergency. When that information is unknown, health agencies should aim for a CMR of below 1.0/10,000/day. A CMR exceeding 2.0/10,000/day indicates a serious situation requiring immediate action. In general, even initially high mortality rates should fall to below 1.0/10,000 /day within 4 to 6 weeks of beginning a basic support program that provides sufficient food and water, immunizations, simple health care, and other immediate needs, assuming that insecurity in not a concern. For children under 5 years of age, the average mortality rate is approximately 1.03/10,000/day in most developing countries during nonemergency times. The rates in Sub-Saharan African countries are somewhat higher at 1.14/10,000/day. When the baseline of the children under 5 mortality rate (U5MR) is unknown, health agencies should aim for a U5MR below 2.0/10,000/day. A higher rate should be thoroughly investigated and addressed, and a rate twice the norm should be considered an emergency situation. Remember that in an emergency the critical task is to decrease the mortality rate, as it reflects a range of stress on the population. It will also be a measure by which the relief effort will be judged.
The following is the procedure for calculating mortality rates.
Crude Mortality Rate =
((Total number of deaths in a given time period)/
(Estimated total population x Number of days in the time period))
Example: 52 deaths in 2 weeks in an affected population of 40,000 people
((52 deaths x 10,000 )/(40,000 people x 14 days))
= 0.93 deaths/10,000/day
Under-5 Mortality Rate: The number of under-5 deaths per 10,000 under-5 children per day.
Under-5 Mortality Rate =
((Total number of deaths in children < 5 y.o. in a given time period)/
(Estimated population < 5 y.o. x Number of days in the time period))
Example: 40 deaths in under-5 kids in 1 week in a population with 25,000 children under 5 years in age
((40 deaths x 10,000 )/(25,000 people x 7 days))
= 2.3 deaths/10,000/day
(2) Morbidity Rate
While mortality rates measure deaths, morbidity rates measure the frequency of illness within specific populations. Unlike mortality rates, which are always an incidence, morbidity may be reported as an incidence or prevalence (see the previous section of definitions). Incidence is the preferred count for diseases of short duration, such as measles, mumps, and rubella. Prevalence is useful for chronic diseases of longer duration such as malnutrition. Time and place must always be specified.
3. Prevention and Control of Infectious Diseases
In an emergency, priority should be given to prevention and control of infectious diseases. The risk of infectious disease transmission increases with overcrowding, poor environmental conditions, poor sanitation, water of inadequate quantity and quality, and poor overall state of health of the affected population. Infectious diseases can dramatically increase morbidity and mortality in emergency situations, particularly in situations involving DPs. More than 80 percent of all deaths in displaced populations are caused by five major conditions: malnutrition, measles, acute respiratory infections (ARIs), diarrheal diseases including cholera and shigella dysentery, and malaria. Other diseases of significance in emergencies include typhoid, hepatitis A, sexually transmitted infections including HIV/AIDS, tuberculosis, diphtheria, meningococcal meningitis, influenza, anthrax, SARS, polio, guinea worm, filariasis, schistosomiasis, scabies, and emerging infections of unknown etiology. Attention should be paid to patterns of antimicrobial resistance in common pathogens. While malnutrition and vitamin deficiencies are not infections, they increase the vulnerability of the population to a variety of infections. Diabetes, HIV/AIDS infection, trauma, and intravenous drug use also increase vulnerability and susceptibility to various infectious diseases.
Improving the public health of the affected population is the cornerstone of disease prevention efforts. In a DP camp situation, special attention should be paid to the location and the plan for the site to minimize crowding and facilitate the development of appropriate water supply and sanitation facilities. Environmental health factors must be considered, such as ensuring adequate safe water and soap, proper disposal of excrement and garbage, the control of rodents and disease-carrying vectors (mosquitoes, flies, ticks, etc.), and education of the population on general public health issues.
One of the first actions in an emergency is to ensure that a surveillance system is in place that can detect serious infectious diseases. Some of these diseases may be monitored on the basis of presenting symptoms; many infectious diseases, however, will require the collection of specimens and expert laboratory confirmation in internationally approved laboratories. It will often be important to detect or confirm patterns of antimicrobial susceptibility and resistance in disease organisms. The rates and trends of diarrhea, bloody diarrhea, rash and fever illness, fever, acute respiratory illnesses, maternal post-partum fever, malnutrition in adults and children, malnutrition with edema, neonatal mortality, infant mortality, and crude mortality should be tracked to evaluate relief efforts.
Measles immunizations for young children are a priority during the early weeks of an emergency even when resources are scarce. Routine immunizations (e.g., diphtheria-tetanus-pertussis [DTP], polio, and tuberculosis [BCG]) can be given later, once health facilities have the capability to institute vaccination programs. It must be remembered that vaccines prevent diseases, but they do not cure them. Therefore, vaccine-preventable diseases must be anticipated and preventative measures such as vaccine campaigns must be implemented early.
During emergencies, rumors of epidemics often run wild. These rumors should be quickly confirmed or refuted by responsible experts, and all relevant information disseminated to the affected population.
b. Common Diseases in Emergencies
This section provides information on diseases that are common in emergency situations. It includes information on the symptoms, transmission, and possible curative and/or preventive measures. Outbreak thresholds have also been included for diseases that have a clearly defined threshold.
Nutritional diseases are addressed in the Nutrition section of this chapter.
(1) Acute Respiratory Infections
Identification. ARIs include both upper respiratory infections (e.g., cold and pharyngitis) and lower respiratory infections (bronchitis, bronchiolitis, and pneumonia) and are marked by cough, fever, otitis media (inflammation of the middle ear), and shortness of breath. ARIs may be mild or may progress rapidly to death, especially among malnourished children. Pneumonia is responsible for the majority of ARI deaths and should be recognized and treated presumptively with antibiotics. Children who die from pneumonia are generally young in age and often die within a short time after becoming ill.
Infectious agents. Multiple bacteria and viruses.
Mode of transmission. Airborne or droplets (caused by coughing), contact with nasal or throat secretions or with objects soiled with secretions from the nose and throat.
Incubation period. Varies, depending on the pathogen, but generally 1 to 10 days.
Communicability period. Varies, depending on the pathogen. Hand washing and/or covering the mouth with cloth or tissues reduces transmission.
Susceptibility and resistance. Infants and elderly at the highest risk, individuals with serious (HIV/AIDS) and/or chronic (TB) illnesses and malnutrition.
Methods of control.
- Preventive measures. (1) Educate patients to wash hands, cover mouth and nose when coughing and sneezing, and place articles soiled with nasal and oral discharges in garbage bins; (2) increase separation between patients to more than 1 m; (3) increase ventilation in buildings and tents and avoid exposure with smoke from cooking fires; and (4) provide adequate, shelter, clothing, and blankets.
- Case Treatment. Provide cross ventilation in patient care areas, and feeding centers. Conduct an active case-finding campaign in homes to identify pneumonia. Cotrimoxazole is recommended for cases of pneumonia diagnosed by the Integrated Management of Childhood Infections guidelines.
- Epidemic measures. Epidemic pneumonias should be assessed by laboratory methods to identify the etiologic agent and antimicrobial susceptibility.
(2) Diarrheal Diseases
Identification. Diarrhea is commonly defined as three or more loose or fluid stools in a 24-hour period. Diarrheal diseases are a major killer of children worldwide, primarily due to poor water quality and inadequate water quantity and sanitation facilities. Complications among young children can result in dehydration and shock. Without rehydration and continued feeding, diarrhea in malnourished children is often fatal.
Infectious agent. Diarrhea is a symptom caused by many different pathogens and pathologies. Common diarrheal conditions include acute bloody diarrhea requiring antibiotic treatment and rehydration if necessary (shigella dysentery); acute watery diarrhea requiring intensive rehydration and antibiotic treatment to shorten the course of the illness and the associated discharge of infectious organisms (cholera); and diarrheas caused by a variety of other pathogens, including various pathogenic and toxogenic strains of E. coli, salmonella, and typhoid. Often rehydration alone will suffice to treat diarrhea, although appropriate antimicrobial therapy may be essential in treating certain organisms. Profuse diarrhea that is watery and pale in color (i.e., rice-water diarrhea) is often a result of cholera, whereas bloody diarrhea with relatively small volume is often the result of shigella dysentery. Cholera and shigella are discussed separately, as they can be particular problems in disaster settings.
Disaster implications. Diarrheal diseases are prevalent in disaster situations due to inadequate sanitation and water supply, as well as overcrowding and lack of knowledge regarding proper hygiene practices such as hand washing.
Methods of control.
- Preventive measures. Provide as much clean water as possible at easily accessible points close to living quarters and institute sanitation services. Promote the importance of hand washing and disposal of excreta; promote exclusive breast-feeding. Very young children are extremely susceptible to diarrheal diseases because of their generally poor hygiene practices and their lack of acquired immunity to various pathogens. Mortality among very young children due to diarrheal diseases is a serious concern because they can quickly become severely dehydrated.
- Case Treatment. Many diarrheal diseases are mild and self-limiting even without treatment. The greatest risk is from dehydration. If fluids and electrolytes can be replaced by drinking and eating or oral rehydration salts (ORS), most diarrhea patients will recover in a relatively short time. Both rehydration and treatment are needed for bloody diarrhea caused by shigella, amebic dysentery, E. coli: 0157, and typhoid.
The following measures should be taken for most diarrheal diseases:
- Confirm the severity of the problem by reviewing morbidity and mortality data. Additional information, such as the location of patients in the camp, the length of time in the camp, and the sources of family water and food, can help pinpoint the source of infection.
- Emphasize sanitation and hand washing. Perform surveys of water supply facilities to identify potential sources of contamination. Disinfect water supplies as appropriate and check treated water for chlorine residual. Perform standard test for the presence of fecal coliform bacteria to determine if fecal contamination of water supplies has occurred.
- Stress the importance of oral rehydration therapy (ORT). Commercially available packets containing the proper mixture of electrolytes (use World Health Organization [WHO] recommendations for the home therapy) are strongly preferred because local preparation with excessive potassium chloride can lead to serious complications and may be fatal. Oral rehydration is the treatment of choice. In situations where a patient cannot drink or has severe dehydration, however, rehydrating him or her appropriately and as quickly as possible with intravenous fluids (IVs) is critical.
Other diseases to consider. Cholera and shigella dysentery are discussed more specifically below.
Identification. Cholera is characterized by sudden onset of profuse, painless, watery stools with vomiting and nausea early in the course of the illness. While only 1 percent of exposed persons may develop symptoms, severe diarrhea may lead to rapid dehydration and even death. The recommended treatment is oral rehydration. IV therapy is used for severe dehydration when oral rehydration is not possible.
Occurrence. Endemic in many countries; cases tend to increase in the rainy seasons.
Mode of transmission. Transmission occurs primarily through ingestion of water/food contaminated with feces containing cholera bacteria. Person-to-person spread generally does not occur, as a very large dose of the organism (as high as 100,000 to 1 million organisms) is required to transmit the disease. Faulty municipal water systems, contaminated surface water, and improper storage of domestic water storage have resulted in large outbreaks.
Incubation period. The incubation period for cholera is usually 2 to 3 days, but can be from a few hours to as long as 5 days.
Communicability period. Patients generally carry the cholera bacteria in their stools only while they are having diarrhea and for a few days after recovery. Occasionally, the carrier state may persist for a few months.
Susceptibility and resistance. Variable; breast-fed infants are protected.
Outbreak threshold. One case confirmed by laboratory. Case fatality rates should be kept at 1 percent or lower.
Methods of control.
- Preventive measures. WHO does not recommend cholera immunization with currently available antigens (see the sections of this chapter on water and sani-tation for recommendations on water supply and safe disposal of excreta). Water should be treated (preferably filtered and chlorinated), particularly water used for infant food preparation. Encourage frequent hand washing and cleaning of feces from contaminated surfaces with 1:100 bleach solution (made from 5-percent sodium hypochlorite solution) is encouraged. Encourage mothers of infants below 6 months of age to breast-feed exclusively.
- Case treatment. Prompt, appropriate rehydration is essential. See section above on diarrhea.
- Epidemic measures. If cholera is suspected, the following measures should be taken:
- Report suspected cases to national public health authorities and WHO.
- Confirm the diagnosis by culturing stool samples from a few suspected cases. Regional public health laboratories or a hospital lab in the capital city should be able to help confirm this diagnosis by testing the samples. Once laboratory confirmation occurs and cases of cholera are established to be prevalent within the population, all cases presenting with cholera symptoms need not be laboratory confirmed.
- Check water and sanitation measures to ensure that water is safe and protected from sewage contamination (the source of the infection in most cases).
(4) Shigellosis (Bacillary Dysentery)
Identification. Shigellosis is an acute bacterial disease characterized by bloody diarrhea accompanied by fever, nausea, sometimes vomiting, and cramps. In typical cases, the stools contain blood, mucus, and pus and will need to be distinguished from amebic dysentery. About a third of the cases present with a watery diarrhea. Convulsions may occur in young children. Mild and asymptomatic infections occur. Illness can last several days to weeks, with an average of 4 to 7 days.
Infectious agent. Diagnosis is made by isolation of shigella from feces or rectal swabs. Infection is usually associated with the presence of pus cells in the stool.
Occurrence. Worldwide, two-thirds of shigellosis cases, and most of the deaths, are in children under 10 years of age. Illness in infants under 6 months is unusual. Outbreaks commonly occur under conditions of crowding and where personal hygiene is poor. Shigellosis is endemic in both tropical and temperate climates.
Mode of transmission. Transmission is almost always by direct or indirect fecal-oral transmission from a patient. Infection may occur after the ingestion of only 10 to 100 organisms. Water transmission may occur as the result of direct contamination. Potential exists for flies to transfer organisms to food, in which they can multiply to an infectious dose.
Incubation period. 12 hours to 1 week.
Communicability period. During acute infection and until the infectious agent is no longer present in feces, usually within 4 weeks after illness. Asymptomatic carriers may transmit infections. Appropriate treatment usually reduces the duration of the illness to less than 1 week.
Susceptibility and resistance. The severity of morbidity and mortality rate are functions of the age and state of health of the victims.
Disaster implications. Shigella is a common cause of dysentery outbreaks.
Outbreak threshold. One laboratory-confirmed case. Case fatality rates should be kept at 1 percent or lower.
Methods of control.
- Preventive measures. Provide large volumes of soap and water to permit hand washing and bathing after toileting, caring for ill family members, and before cooking and eating. Provide toilet facilities which are separated from bathing areas and drinking water sources.
- Case treatment. See section above on diarrhea. Appropriate antibiotic therapy is essential.
Identification. AIDS (acquired immunodeficiency syndrome) is the late state of a severe disease syndrome caused by HIV (human immunodeficiency virus) that affects the immune system. From 2 weeks to 2 months after infection, the initial symptoms of fever, sore throat, and cough appear, lasting 1 or 2 weeks. The next clinical manifestations (opportunistic infections or cancer) may not appear for several months or years. The timing seems to depend on the severity of immune system dysfunction.
Occurrence. Worldwide, with the disproportionate burden in Africa.
Mode of transmission. Transmission occurs through:
(a) sexual intercourse; (b) reuse of needles; (c) transfusion of or exposure to infected blood; and (d) mother-to-child transmission during pregnancy, labor and delivery, or through breast-feeding.
Incubation period. Variable; the time from infection and detectable antibodies is usually 1 to 3 months.
Communicability period. Lifelong.
Susceptibility and resistance. Nearly universal; women are at increased risk of sexual transmission.
Methods of control.
- Preventive measures. Sexually transmitted disease treatment programs, as presence of sexually trans-mitted infections increases the risk of transmission. Condom use has been shown to reduce the risk of transmission. Programs that reduce the economic vulnerability of young girls to older men reduce rates of infection. Distribution of relief commodities to women head-of-households reduces their economic dependence on men and reduces the need to exchange sex for survival commodities.
- Case treatment. Post-exposure use of condoms decreases the risk of transmission. Provide treatment for opportunistic infections (e.g., cotrimoxazole and/or TB preventive therapy) that may hasten death. Typhoid is a common opportunistic infection in disaster settings.
- Epidemic and disaster measures. Protective meas-ures for women and children that reduce risk of rape and the need to exchange sex for survival commodities. Procure adequate number of single-use syringes. Used syringes should be destroyed to reduce injury or reuse. Blood donors should be tested, before donation, with rapid HIV/AIDS tests. Condoms should be procured and distributed. Sexually transmitted infections should be treated using syndromic protocols if rapid diagnostic tests are unavailable.
Identification. Measles is a highly contagious viral infection characterized initially by cough, running nose, and red eyes (conjunctivitis). These symptoms are followed in 3 to 7 days by a high fever, which precedes a dusty red, raised blotchy rash that begins on the face (and may extend over the rest of the body) and lasts 4 to 6 days. Measles spreads very rapidly throughout a population and can result in case fatality rates of more than 10 percent in the presence of common complications such as malnutrition, diarrhea, and pneumonia. Measles also exacerbates vitamin A deficiency, which can lead to blindness.
Mode of transmission. Principally airborne. Measles can be transmitted to persons entering a room after the patient has left.
Incubation period. About 10 days.
Communicability period. Usually about 4 days before the appearance of the rash until 4 days after the appearance of a rash.
Susceptibility and resistance. More common in the malnourished, especially in vitamin A deficiencies. Immunity after an illness is permanent.
Disaster implications. Children admitted to feeding programs should be immediately vaccinated against measles if they have not been vaccinated or if their status is uncertain. During outbreaks, home visitors and community health workers should conduct active case finding using a standard case definition for measles. All suspected cases should be referred promptly to a health facility. These children should have their nutritional status monitored regularly to make sure that they are eating their rations or breast feeding.
Methods of control.
- Prevention measures. A coverage rate of measles vaccine below 80 percent in a displaced population should be regarded as an emergency. Measles vaccines should ideally be given as soon as the at-risk population can be accessed, since action after the disease is detected in high-density populations may be too late. If significant malnutrition is present in the under-5 population, implementing a measles vaccination program as soon as possible is absolutely essential.
- Plans should be made in coordination with the national or regional measles strategy, and in collaboration with the WHO Expanded Program for Immunization (EPI) recommended strategy regarding strain of vaccine, use of vaccine meeting WHO quality standard, use of auto-destruct syringes, single-use mixing syringes, target age range, goal to control disease or interrupt transmission, opportunity for a second dose, and monitoring of adverse events. Complete information is available at the WHO Web site, http://www.who.org. Relief objectives and local epidemiology will guide whether children are immunized from 6, 9, or 12 months of age. No harm will occur if children receive more than one dose. If vaccine supplies are too limited for public health purposes, malnourished, HIV positive, and hospitalized children should be vaccinated first. The vaccine should not be given to girls who may be pregnant, or those children with severe egg allergies. The vaccine does not contain preservatives and must be discarded within 6 hours after opening. Deaths from toxic shock have resulted when vials were retained for subsequent sessions.
- If children have not received vitamin A during the previous month, all children of 12 months of age or older should receive a prophylactic oral dose of 200,000 international units (IU) of vitamin A. Infants less than 12 months should receive 100,000 IU. This should be repeated every 6 months as part of the routine vitamin A supplementation schedule. Children with measles, and adults and children with signs of vitamin A deficiency such as night blindness or bitot spots should be given treatment doses.
- Case Treatment. No treatment specifically for measles is available. Supportive treatment of symptoms, such as fever and diarrhea, is recommended. Routine treatment with antibiotics to prevent secondary infection with bacterial pneumonias is not recom-mended. Vitamin A should be given and therapeutic or supplemental feeding may be necessary.
- Isolation. Patients with rash and fever illnesses should be removed from high-density areas, patient waiting areas, and feeding care areas where nonimmunized susceptible patients are present. Isolation is a priority wherever possible and when widespread exposure has not already occurred. A shaded and well-ventilated area away from vulnerable populations may need to be established, particularly if dealing with large numbers of cases.
- Epidemic measures. Emergency vaccination campaigns often inadvertently immunize persons who have already been infected and thus already have immunity. An analysis of cases by date, exposure history, geographic area, previous vaccination history, and tracking of case fatality rates may identify pockets that could be successfully immunized, and help evaluate efforts.
- Outbreak threshold. One case.
Identification. Malaria is a protozoal parasitic infection of red blood cells, spread by mosquitoes. The disease can have many presentations, but is typically characterized by headaches, high fever with chills, malaise, and sweats that can progress to kidney and liver failure, shock, and even coma. Malaria, when present, may be a leading cause of death, illness, miscarriages, clinic visits, and hospitalization. Children, pregnant women, immunocompromised individuals, and malnourished individuals are particularly at risk. Populations arriving from non-malarious areas to areas where malaria is endemic may experience higher attack rates due to a lack of immunity.
Part of the disaster assessment should be determining whether malaria is endemic in the region where DPs are currently located, as well as the regions from which persons have been displaced; the species of mosquitoes present; breeding seasons and types of malaria; patterns of drug resistance; national norms of diagnosis and treatment; experience with treated bed nets (long-lasting treated nets should be used) and indoor residual spraying programs (must be started at the onset of an outbreak to be effective in outbreak control); availability and use of intermittent preventive treatment; and laboratory capabilities available for public health confirmation and individual case management. The population’s experience, understanding, and access to preventive and therapeutic norms should also be explored.
Infectious agent. Four species of human malaria exist: Plasmodium vivax, Plasmodium falciparum, Plasmodium malariae, and Plasmodium ovale. P. vivax and P. falciparum are the most common. P. falciparum has the highest case fatality rates and requires prompt treatment.
Occurrence. Tropical areas throughout the world. P. falciparum is rare in the Americas.
Mode of transmission. Various species of mosquitoes of the genus Anopheles. Malaria may also be transmitted by injection or transfusion of blood from infected persons or by the use of contaminated needles and syringes. Congenital transmission occurs rarely, but stillbirth from infected mothers is more frequent.
Incubation period. The time between the infective bite and the appearance of clinical symptoms is approximately 7 to 14 days for P. falciparum and 8 to 14 days for P. vivax.
Communicability period. For infectivity of mosquitoes, as long as infective sexual forms (gametocytes) of the plasmodium organism are present in the blood of patients. This varies with the species and strain of the parasite and with response to therapy. Untreated or insufficiently treated patients may be a source of mosquito infection for 1-2 years in P. vivax malaria, and generally not more than 1 year in P. falciparum malaria. The mosquito remains infective for life.
Susceptibility and resistance. Young children and pregnant women are more vulnerable, even in areas of high transmission, where the overall population may have semi-immunity.
Disaster implications. Malaria outbreaks are common during complex emergency situations where populations are moving from areas of low transmission to areas of high transmission. Such populations are vulnerable because they do not have immunity, and they are often more susceptible to infection due to their difficult circumstances. Populations impacted by complex emergencies often exhibit high rates of malnutrition, HIV/AIDS, and other infections that make them more vulnerable to malaria outbreaks. Malaria outbreaks are also common both after severe floods (more pools for mosquito breeding), and after a prolonged drought, as mosquito eggs can stay in the soil during dry periods and hatch once water is available.
Outbreak threshold. No specific definition exists; however, an increase in the number of cases above what is expected for the time of year among a defined population in a defined area may indicate an outbreak.
Methods of control.
- Preventive measures. Preventive measures should be directed to preventing mosquito bites. These include the use of long-lasting insecticide-treated bed netting and tarpaulins, wearing protective clothing, and control of mosquitoes through insect abatement programs such as indoor residual spraying. Programs such as larvaciding are not generally effective during the acute stages of an emergency because locating and treating all potential breeding sites in an unstable emergency situation is extremely difficult. Where capacity exists, pregnant woman and children should be given intermittent preventive treatment with an antimalarial appropriate to local drug resistance patterns.
- Case Treatment. In disasters, the diagnosis of malaria is often made clinically; however, take advantage of Rapid Diagnostic Tests (RDTs) for malaria diagnosis during emergencies because laboratory facilities are often unavailable or are overwhelmed. Symptomatic diagnosis of patients presenting with fever is often incorrect, and leads to incorrect treatment of patients with expensive therapies, wasting valuable time and resources. Microscopy or other laboratory tests should be used wherever available. Nevertheless, in an affected area without microscopy or available RDTs, assessments should address whether fevers of unknown origin and/or fevers with or without altered states of consciousness should be treated presumptively for malaria. The use of RDTs should be made a priority for effective diagnosis.
- Of critical importance during potential outbreaks in disaster settings is to work with the Ministry of Health, WHO, the United Nations Children’s Fund (UNICEF), and other key partners to ensure that appropriate drugs are being used to treat patients. In most cases where significant resistance occurs to drugs such as chloroquine, Artemisinin Combination Therapies are indicated. The use of Intramuscalar Artemether and Rectal Artesunate saves the lives of patients with severe falciparum malaria who do not have immediate access to healthcare facilities. Avoiding the use of malaria-treatment drugs in cases where the malaria parasites have acquired resistance is extremely important. Artemisin-based drugs must be used in combination with other drugs except in specific indicated circumstances, to preserve the efficacy of these drugs. Drug resistance patterns should be monitored.
(8) Meningococcal Meningitis
Identification. Meningitis is an infection of the fluid and lining surrounding the brain spinal cord. High fever, headache, and stiff neck are common symptoms of meningitis. These symptoms can develop over several hours, or they may take 1 to 2 days. Other symptoms may include nausea, vomiting, photophobia, confusion, and sleepiness. The term "meningococcal meningitis" refers to meningitis caused by Neisseria meningitides (meningococcus), which is responsible for epidemics, particularly in Sub-Saharan Africa. Meningitis caused by other organisms should be ruled out before identifying the infection as meningococcal meningitis.
Infectious agent.N. meningitide, diverse types.
Occurrence. Different types of meningitis have peak occurrences at different times of the year, and in different places. The incidence of meningococcal disease peaks in the winter, with seasonal risk of meningococcal disease epidemics in parts of West Africa, primarily during the dry season.
Mode of transmission. Bacterial forms are transmitted through the direct exchange of respiratory and throat secretions.
Incubation period. Depends on the specific agent.
Communicability period. Depends on the specific agent.
Susceptibility and resistance. Susceptibility to the clinical disease is low and decreases with age; a high ratio of carriers to cases prevails.
Disaster implications. Crowded living quarters may increase transmission.
Outbreak threshold. In stable populations greater than 30,000 people, an outbreak threshold of 15 cases per 100,000 persons per week is indicative of a potential severe outbreak. In populations of fewer than 30,000 people, the threshold is five cases per week or a doubling of the number of cases over a 3-week period.
Methods of control.
- Preventive measures. Quadrivalent, monovalent, and polyvalent vaccines are currently available to prevent meningococcal meningitis caused by serogroups A, C, Y, and W135. Therefore, the cases must be laboratory confirmed before starting any vaccination program.
- Case treatment. All bacterial forms, especially meningococcus, should be treated aggressively with antibiotics. A single injection of long-acting chloramphenicol in oil has been proven effective in meningococcal epidemics. Penicillin, ampicillin, and chloramphenicol are also effective but require multiple does and in severe cases, IV administration.
(9) Tuberculosis (TB)
Identification. Tuberculosis is a mycobacterial disease that is a major cause of disability and death in many parts of the world. The initial infection usually goes unnoticed; tuberculin skin test sensitivity appears within 2 to 10 weeks. The initial infection may progress directly to pulmonary tuberculosis or to other serious outcomes. Serious outcome of the initial infection is more frequent in infants, adolescents, young adults, and the immunosuppressed.
Infectious agent.Mycobacterium tuberculosis.
Mode of transmission. The most common route of transmission is inhalation of the bacilli from prolonged personal contact with a person with pulmonary TB. Effective chemotherapy in HIV negative persons usually eliminates communicability within a few weeks, although treatment may need to continue for 6 months or longer. Untreated or inadequately treated people can be infectious for years.
Incubation period. About 2 to 10 weeks.
Communicability period. Persons should be considered infectious if laboratory tests determine the presence of acid-fast bacilli in the sputum. Generally, nonpulmonary TB patients do not pose a risk to the general population.
Susceptibility and resistance. Ten percent of healthy persons will develop TB disease after being infected. Persons with immune systems weakened by HIV/AIDS, cancer, age, or malnutrition will develop disease at much higher rates. Disease from Multi-Drug Resistant TB (MDR-TB) and untreated TB has a case fatality rate of 50 percent.
Disaster implications. Because TB is considered an opportunistic infection of HIV/AIDS, a greater risk of increased TB infections is associated with disasters that occur in countries with high HIV/AIDS prevalence. A first priority for treatment in disasters is to identify and resume therapy for individuals already undergoing treatment. Failure to complete treatment may spread drug resistant organisms in the population. The decision to establish therapy in other persons who have not begun treatment will depend on the ability to provide monitored therapy through completion. These therapies have been achieved in difficult settings but should be decided on a situation-by-situation basis.
Methods of control.
- Preventive measures. Promptly diagnose and treat potentially infectious persons with TB disease, and establish case finding and treatment programs for those with the disease. Use of prophylactic therapy will depend on the available resources and ability to track patients.
- Case treatment. Treatment norms should be established in conjunction with WHO and national norms and should be adhered to by all agencies offering therapy. Inappropriate therapy is more dangerous to public health over the long term than no therapy due to the risk of drug resistance.
4. Health Care Provision
Health care in emergency settings generally provides both preventive and curative services. Curative measures vary depending on the emergency and the amount and quality of preventive care. A limiting factor for the expansion of services is often not the lack of trained personnel, but the lack of adequate quantities of water and facilities for safe reprocessing of equipment. Inpatient care facilities can amplify the presence of infections ranging from MDR-TB to Ebola to cholera to measles, and inpatient facilities should only be established if they can be done safely and cost effectively.
Particularly where several organizations are involved, close attention must be paid to ensure a common standard of appropriate health care. Standardized and evidence-based treatment schedules are essential. In the absence of diagnostic capabilities, syndromic protocols that have been validated for sensitivity and specificity can be used. Unless treatment is administered immediately, clear oral and written guidance on the dosage and schedule must be given to each patient in his or her native language. In addition, organizations should work together to ensure a fair distribution of available services.
Treatment that is inappropriate for people’s needs and circumstances can be useless and wasteful, and can also have a negative effect on their attitude toward health care and preventive measures in general.
To the greatest extent possible, the affected population should be given responsibility for their own health. Outside health workers must understand the population’s own beliefs regarding health and disease. Services should be operated with, rather than for, the affected population. If not, health care services will be less effective, may be distrusted by the population, and are likely to collapse when expatriate staff leave.
a. Health Care Personnel
Strong emphasis should be placed on the training and upgrading of the clinical skills of selected health workers, particularly those who already have health-related roles in the community (e.g., traditional healers and midwives). Even persons with no prior experience can be very effective health workers in settings with supervision, well-defined responsibilities, and a scope of action limited to tasks that can be done safely.
As a general principle, the order of preference for selecting health personnel is (1) members of the affected population,
(2) experienced nationals or residents, and (3) international relief personnel. Most emergencies will require some combination of these sources. Personnel selections should be made in cooperation with the national services. An important consideration may be the government’s attitude toward foreign medical personnel, including the recognition of qualifications and authority to practice medicine.
In a major emergency, a health coordinator may be assigned responsibility for planning and developing appropriate health care programs, establishing standards, monitoring the quality of services, and ensuring proper liaison and coordination among the health ministry and other international organizations on health matters.
b. Levels of Health Care Treatment
In emergency situations, the population must be able to access appropriate treatment. In most emergency settings, access to centralized health care is problematic. If basic health care facilities are not readily available, hospitals or major health centers can be swamped by patients demanding treatment for simple conditions that could have been treated elsewhere. What is required, therefore, is a community-based health service that identifies and treats those in need of health care and provides that care at the appropriate level.
Sphere standards should be followed for ratios of health facilities to population and staffing per health facility. For example, there should be one community health worker per 500 to 1,000 population; one skilled/traditional birth attendant per 2,000 people; etc.
The first level of health care in emergency settings is provided by the community health worker (CHW), who is responsible for a section of the population and works among them to provide outreach services such as home visits, case finding, and followup. CHWs can track births and deaths in the population, the emergence of new issues and concerns, and be a link between providers and patients. They can also implement basic communitywide preventive measures, including transmission of public health messages, distribution of health commodities such as bednets, condoms, or iron tablets, and provide directly observed TB therapy. CHWs can provide identification of health and nutritional problems, and refer patients to a clinic if simple on-the-spot treatment is not possible. Disease information gathered from the homes or representative samples is often more important than clinic-based information, which does not represent the entire population.
The second level of health care is a local health facility. According to Sphere standards, one health facility should be established for every 10,000 people, with a total of two to five staff. The staff should include a minimum of one qualified health worker (i.e., a formally trained clinical provider, nurse, doctor, medical officer or medical assistant) providing about 50 consultations per day, assisted by two to three health workers who provide ORT, dressings, registration and admissions, etc. In acute emergencies with mortality above 1 per 10,000 people, it will be necessary to have separate supervisors for the CHWs providing outreach and for the staff providing clinical services.
Hand washing facilities with soap, water and a means of drying hands are the minimal requirements needed to reduce the spread of disease between patients. Large volumes of potable water, latrines, and a waste area for feces, body fluids, and medical waste are essential services at all health facilities. An incinerator should be established for burning medical waste and sharps (used needles). Alternatively, sharps containers may be transported to another location for final burial or destruction.
The third level of health care would be a central health facility (for a population of approximately 50,000 people) with a minimum of five qualified health workers, including one physician. There should be 24-hour services for inpatient care; one qualified health worker for outpatient services; one qualified health worker per 20 to 30 beds; one non-qualified worker for ORT; one to two for pharmacy; one to two for dressings, injections, sterilization; one lab technician; and several non-qualified workers for registration, security, etc.
The next level of health care is the referral hospital. Essential services required at this level are the ability to attend to births and cases requiring inpatient care. Ideally, it should also provide emergency obstetrical care, blood transfusions, therapeutic feeding programs, minor surgical procedures, referral cases that could not be handled at a lower clinic level, as well as general reproductive health services. Staff should be assisted by one doctor with surgical skills; one nurse is needed for 20 to 30 beds per shift.
With the exception of short-term, self-contained emergency trauma and burn hospitals that accompany search and rescue teams, the establishment of special hospitals for populations affected by a disaster should generally be avoided. Hospital-level care is not cost effective, as it requires enormous volumes of water and energy, is skilled-labor intensive, provides only curative services, rarely continues to function once outside support is withdrawn, and is inappropriate for long-term needs. Once established, special hospitals are extremely difficult to close without creating ill will. Therefore, special hospitals should be provided only if a clear and continuing need exists that cannot be met by existing national hospitals. If the need for such a special hospital exists (e.g., to treat time-limited outbreaks such as cholera), the number of beds required would depend on the condition of the population. For example, one bed might be required per 2,000 people in the early stages of an emergency, requiring two doctors and six nurses plus auxiliary support.
5. Health Education
The importance of health education is widely accepted. It may be a difficult task, however, to persuade at-risk populations to change long-established habits that increase their health risks. During the emergency phase, priority topics of any health education program should be directly related to immediate public health problems, such as the disposal of human excreta and refuse or disease prevention. Trained teachers from the population and respected elders are likely to be more effective than outsiders in communicating basic health principles and practices.
6. Medical Supplies
Emergency medical supplies should draw on in-country resources to the greatest extent possible, if supplies consistent with international norms (e.g., WHO, UNICEF) are available.
a. The New Emergency Health Kit
WHO has a standard list of essential drugs and medical supplies for use in an emergency. They are packaged together in the New Emergency Health Kit, which has been accepted by many organizations and national authorities as a reliable, standardized, inexpensive, and quickly available source of essential drugs and health equipment needed in an emergency situation. Its contents are calculated to meet the needs of a population of 10,000 persons for 3 months.
The kit consists of two different units of drugs and medical supplies: the Basic Unit (10 per kit) and the Supplementary Unit (1 per kit).
The Basic Units contain oral drugs, medical supplies, treatment guidelines, and some simple equipment for use by basic healthcare workers with limited training. Each Basic Unit weighs 45 kg and occupies 0.2 m3.
The Supplementary Unit is designed for use by trained health workers serving a population of 10,000 people for 3 months. The Supplementary Unit, which should be used with a Basic Unit, contains injectable drugs, IV fluids, IV tubing and catheters, nasogastric tubes, syringes, minor surgical equipment, essential infusions, supplies, and equipment. The Supplementary Unit weighs 410 kg and occupies 2 m3.
The total New Emergency Health Kit, including the 10 Basic Units and 1 Supplementary Unit, weighs about 860 kg and occupies 4 m3. An entire kit can be transported using a standard pickup. It should be noted that these kits are designed to meet only initial needs pending the establishment of a regular system for medical supplies.
Basic equipment for pelvic exams and deliveries is provided in a separate Minimum Initial Services Package for reproductive health.
Medical supplies can also be ordered through the UNICEF supply warehouse that has a stockpile of prepackaged drugs and supplies. These supplies must be ordered through OFDA/W, not directly from the field.
Vaccines should be provided in conjunction with national-, UNICEF-, or WHO-sponsored programs. The provision of supplies through local procurement channels should be explored. Before immunization, careful planning should determine whether the vaccines will have vaccine vial monitors that detect heat exposure; the need for freeze indicators for freeze sensitive vaccines (tetanus toxoid, tetanus toxoid with reduced diphtheria content, DTP, hepatitis, and Hib pneumonia); and the availability of cold packs, vaccine carriers, cold boxes, existing cards, single-use syringes, sharps containers, cotton, thermometers, and other required supplies. Most vaccines require protection from excessive heat exposure and some require protection from freezing.
Temperature logs should be posted on refrigerators and freezers. Temperatures should be checked twice daily and noted on cards accompanying the vaccine. Storage facilities located at the central (capital city) and regional level should have temperature alarms and backup (emergency) generators.
Vaccines should be stored on central shelves and not in refrigerator doors. Take into account also the time needed to clear customs.
c. OFDA Guidelines for Pharmaceutical Donations
OFDA/W, Assessment Teams, and DARTs may receive offers of pharmaceutical donations from a variety of organizations. Often, these organizations also seek assistance in transporting the donated products. OFDA/W will normally work directly with the organizations regarding transport issues, but will often request Assessment Teams and DARTs to validate the field requirement for the pharmaceutical product and ensure the capability of the identified consignee to receive, transport, store, distribute, and monitor the use of the product. Clearance for medical and pharmaceutical products is granted if these goods meet the criteria specified by OFDA, and are listed in the WHO Guidelines for Drug Donations. Assessment Teams and DARTs should use the following criteria to ensure objective and consistent field input on whether to accept or reject donated pharmaceutical products:
- Donations must be based on an analysis of needs.
- The proposed product is appropriate to the disaster situation and the objectives of the program.
- Product selection and distribution must conform to existing policies and capabilities (adherence to any existing national policies, the WHO Essential Drug List, etc.).
- Products must be easily identified through labels and written materials.
- The shelf life must allow time for transportation and distribution. The expiration date must be at least 12 months in the future of the products’ arrival in the recipient country (an expiration date of less than 12 months may be allowed on a case-by-case basis, upon approval by the OFDA Health Officer tracking pharmaceuticals).
- Unsolicited and unnecessary donations are wasteful and should not be encouraged.