The World Health Organization has warned that the number of those affected by the earthquake that struck Turkey and Syria may reach 23 million, including about 5 million in a fragile situation, and expressed its fear of a major health crisis whose damages may exceed the losses of the earthquake.
Humanitarian organizations have also expressed concern about the spread of the cholera epidemic, which has re-emerged in Syria.
What are the potential epidemics that may appear after an earthquake or natural disaster?
Health threats
The World Health Organization says that health threats from earthquakes can vary with the magnitude of the earthquake, the nature of the built environment (such as poor housing or urban slums), and the secondary effects of an earthquake, such as tsunamis or landslides.
Earthquakes can have immediate and long-term effects on health.
The direct health effects of the earthquake include:
Deaths and injuries due to shocks due to building collapses.
Shock deaths and injuries due to secondary earthquake effects, such as tsunami drowning or fire burns.
Medium-term health effects include:
Secondary infections of untreated wounds.
Increasing the severity of the disease and the risks of complications associated with pregnancy and childbirth due to the uninterrupted provision of obstetric services and modern childbirth.
Potential risks of communicable diseases, especially in densely populated areas.
Increased disease severity and risk of chronic disease complications due to interruption of treatment.
Increased psychosocial needs.
Possible environmental pollution due to chemical / radioactive agents after the destruction of industrial infrastructure.
Earthquakes can also damage health facilities and transportation, which can disrupt service delivery and access to care.
Health workers may not be able to reach health facilities that are still functioning and may lose medical supplies.
What potential epidemics may appear after an earthquake or natural disaster?
The following infectious diseases are associated with outbreaks after natural disasters, including:
Water-related infectious diseases
Access to safe water can be jeopardized by a natural disaster.
Diarrheal disease outbreaks can occur after drinking water has been contaminated.
Diseases that may spread after natural disasters include cholera and salmonella.
In Muzaffarabad, Pakistan, an outbreak of acute watery diarrhea occurred in an unequipped camp of 1,800 people after the 2005 earthquake. The outbreak involved more than 750 cases, mostly among adults, and was brought under control after adequate water and sanitation facilities were provided.
In the United States, diarrheal disease was observed after Hurricanes Allison and Katrina, and Katrina evacuees were confirmed to have norovirus and salmonella.
Hepatitis A and E are also transmitted through the faecal route, and are associated with an inability to access safe water and sanitation.
Leptospirosis is a bacterial disease of animal origin that is prone to epidemics, and may be transmitted through direct contact with contaminated water.
Rodents excrete large amounts of leptospira in their urine, and transmission occurs through skin and mucous membrane contact with water, moist soil, vegetation, or mud contaminated with rodent urine.
Crowding-related diseases
Crowding is common among populations displaced by natural disasters and can facilitate the transmission of communicable diseases, including measles.
Outbreaks of measles and the risk of transmission after a natural disaster depend on basic immunization coverage among the affected population, particularly among children under 15 years of age.
A measles outbreak was recorded in the Philippines in 1991 among people displaced by the eruption of Mount Pinatubo, involving more than 18,000 cases.
Neisseria meningitidis is transmitted from person to person, especially in cases of crowding.
Meningitis cases and deaths have been documented among displaced people in the Indonesian province of Aceh and Pakistan.
A rapid response with antimicrobial prophylaxis, as seen in Aceh and Pakistan, can halt transmission.
Large-scale outbreaks have not been reported recently among disaster-affected populations, but are well documented in conflict-displaced populations.
Acute respiratory infections are a major cause of illness and death among the displaced, particularly among children under 5 years of age.
Lack of access to health services and antimicrobial agents for treatment increases the risk of death from acute respiratory infections.
Risk factors among the displaced include overcrowding, exposure to indoor cooking using open flames, and malnutrition.
The incidence of acute respiratory infections quadrupled in Nicaragua 30 days after Hurricane Mitch in 1998, and acute respiratory infections were responsible for the highest number of cases and deaths among those displaced by the 2004 Aceh tsunami and the 2005 earthquake in Pakistan.
Insect related diseases
Natural disasters, especially hurricanes and floods, can affect vector breeding sites and transmission of vector-borne diseases.
While initial floods may wash away existing mosquito breeding sites, standing water from heavy rainfall or overflowing rivers can create new breeding sites.
This situation (usually with a delay of a few weeks) can lead to an increase in the vector population and the potential for disease transmission, depending on the local mosquito vector species and its preferred habitat.
Overcrowding of infected and susceptible hosts, weak public health infrastructure, and interruption of ongoing control programs are all risk factors for transmission of vector-borne diseases (ie, insects that transmit disease).
Outbreaks of malaria in the aftermath of floods are a well-known phenomenon.
An earthquake in the Atlantic region of Costa Rica in 1991 was associated with habitat changes that were beneficial to reproduction and preceded a sharp rise in malaria cases.
In addition, periodic floods associated with the El Niño (Southern Oscillation) phenomenon have been associated with epidemics of malaria in the dry coastal region of northern Peru.
Dengue transmission is affected by atmospheric conditions, including precipitation and humidity, and often exhibits strong seasonality.
Other diseases associated with natural disasters
Tetanus is not transmitted from one person to another, but is caused by a toxin released by the anaerobic tetanus bacillus Clostridium tetani.
Infected wounds are associated with morbidity and death from tetanus, particularly in areas with low levels of immunization coverage.
Disaster related service outages
Disaster-related power outages may disrupt water treatment and supply plants, increasing the risk of waterborne diseases.
Power shortages may also affect the proper functioning of health facilities, including maintaining the vaccine cold chain.
There was an increase in diarrheal diseases in New York City in the aftermath of the Great Blackout in 2003, when 9 million people in the area had no power for several hours to two days, and cases of diarrhea became widespread.
Corpses and disease
The sudden presence of large numbers of dead bodies in the disaster-affected area may increase fears of disease outbreaks, although there is no evidence that dead bodies pose a risk for epidemics after natural disasters.
When the cause of death is directly a natural disaster, the human remains do not pose a risk of disease outbreak.
Dead bodies pose health risks only in a few cases that require specific precautions, such as deaths from cholera or hemorrhagic fever.
The following points summarize some recommendations for handling dead bodies:
Burial is preferable to cremation in mass casualty cases.
Every effort should be made to identify the dead bodies.
Mass burials should be avoided if at all possible.
Families should have the opportunity (and access to materials) to conduct culturally appropriate funerals and burials in accordance with social customs.
Where existing facilities such as cemeteries or crematoriums are not sufficient, alternative sites or facilities must be provided.
For workers who routinely handle dead bodies, they must ensure that:
Take universal precautions for blood and body fluids.
Use and dispose of gloves properly.
Use body bags, if available.
Wash hands with soap after touching dead bodies and before eating.
Disinfection of vehicles and equipment.
Corpses do not need to be disinfected prior to disposal (except in cases of cholera, shigellosis, or hemorrhagic fever).