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'Terrible double blow' as powerful cyclone lashes parts of India already hit hard by COVID-19
Cyclone Tauktae made landfall in Gujurat with sustained winds of 165 km/h
The Associated Press
Posted: 3 Hours Ago
Last Updated: 2 Hours Ago
India Cyclone
A woman wearing a mask walks through a waterlogged street in Mumbai, India, on Monday. (Rafiq Maqbool/The Associated Press)
A powerful cyclone that emerged in the Arabian Sea made landfall on India's western coast on Monday, hours after authorities evacuated hundreds of thousands of people and suspended COVID-19 vaccinations in one state.
Cyclone Tauktae, the most powerful storm to hit the region in more than two decades, came ashore in Gujarat state with heavy rain, a battering storm surge and sustained winds of up to 165 kilometres per hour, the India Meteorological Department said.
Forecasters warned of possible extensive damage from high winds, heavy rainfall and flooding in low-lying areas.
ADVERTISEMENT
Twelve people were reported dead before the storm hit land and hundreds of thousands were evacuated, a process complicated by the coronavirus pandemic.
The massive storm came as India is battling a devastating coronavirus surge — and both the storm and the virus could exacerbate the effects of the other. The storm had already led to the suspension of some vaccination efforts and there is greater risk of virus transmission in crowded evacuation shelters.
India Cyclone
A bus was half submerged by rains from Cyclone Tauktae. Authorities raced to evacuate hundreds of thousands of people and suspended COVID-19 vaccinations in Gujurat ahead of the storm. (Rafiq Maqbool/The Associated Press)
COVID-19 vaccinations suspended
In Gujarat, vaccinations were suspended for two days and authorities worked to evacuate hundreds of thousands of people to temporary relief shelters. The state's chief minister, Vijay Rupani, asked officials to ensure that oxygen supplies for hospitals are not disrupted.
In Maharashtra, six people were killed, the Press Trust of India news agency reported. The state's capital, Mumbai, was lashed by heavy rain and strong winds, forcing authorities to suspend operations at the city's main airport.
Fishing boats off the coast in both states returned to harbour and thousands of rescue and relief teams, along with ships and aircraft, were deployed for recovery operations.
India Cyclone
Fishermen try to move a fishing boat to a safer ground on the Arabian Sea coast in Mumbai on Tuesday ahead of Cyclone Tauktae. (Rafiq Maqbool/The Associated Press)
Rain from the storm earlier killed six people in Kerala, Karnataka and Goa states over the weekend before it moved along the western coastline.
ADVERTISEMENT
Virus lockdown measures, meanwhile, could slow relief work after the storm, and damage from the storm could destroy roads and cut vital supply lines for vaccines and medical supplies needed for virus patients. The damage is also likely to particularly hurt the poor, who are already stretched to the limit by the economic impact of the virus.
Popularity crumbles for Indian PM Modi as devastating COVID-19 surge continues
COVID-19 battle puts India's government on 'war footing'
The South Asia head of the International Federation of Red Cross and Red Crescent Societies, Udaya Regmi, said the cyclone is a "terrible double blow" for families that have already been hit by COVID-19 infections and deaths.
"The potential impacts of Cyclone Tauktae are frightening as this monster storm threatens the state of Gujarat. Every effort must continue to keep people safe from this dangerous storm and the raging pandemic," Regmi said.
India's western coast is no stranger to devastating cyclones, but changing climate patterns have caused them to become more intense, rather than more frequent.
In May 2020, nearly 100 people died after Cyclone Amphan, the most powerful storm to hit eastern India in more than a decade, ravaged the region and left millions without power.
India cyclone
(CBC News)
Epidemics after Natural Disasters
John T. Watson, Michelle Gayer, and Maire A. Connolly
Additional article information
Associated Data
Supplementary Materials
Abstract
The relationship between natural disasters and communicable diseases is frequently misconstrued. The risk for outbreaks is often presumed to be very high in the chaos that follows natural disasters, a fear likely derived from a perceived association between dead bodies and epidemics. However, the risk factors for outbreaks after disasters are associated primarily with population displacement. The availability of safe water and sanitation facilities, the degree of crowding, the underlying health status of the population, and the availability of healthcare services all interact within the context of the local disease ecology to influence the risk for communicable diseases and death in the affected population. We outline the risk factors for outbreaks after a disaster, review the communicable diseases likely to be important, and establish priorities to address communicable diseases in disaster settings.
Keywords: Disasters, epidemiology, outbreaks, surveillance, risk assessment, communicable diseases, perspective
Natural disasters are catastrophic events with atmospheric, geologic, and hydrologic origins. Disasters include earthquakes, volcanic eruptions, landslides, tsunamis, floods, and drought. Natural disasters can have rapid or slow onset, with serious health, social, and economic consequences. During the past 2 decades, natural disasters have killed millions of people, adversely affected the lives of at least 1 billion more people, and resulted in substantial economic damages (1). Developing countries are disproportionately affected because they lack resources, infrastructure, and disaster-preparedness systems.
Deaths associated with natural disasters, particularly rapid-onset disasters, are overwhelmingly due to blunt trauma, crush-related injuries, or drowning. Deaths from communicable diseases after natural disasters are less common.
Dead Bodies and Disease
The sudden presence of large numbers of dead bodies in the disaster-affected area may heighten concerns of disease outbreaks (2), despite the absence of evidence that dead bodies pose a risk for epidemics after natural disasters (3). When death is directly due to the natural disaster, human remains do not pose a risk for outbreaks (4). Dead bodies only pose health risks in a few situations that require specific precautions, such as deaths from cholera (5) or hemorrhagic fevers (6). Recommendations for management of dead bodies are summarized in the Table.
Table
Table
Principles for management of dead bodies*
Despite these facts, the risk for outbreaks after disasters is frequently exaggerated by both health officials and the media. Imminent threats of epidemics remain a recurring theme of media reports from areas recently affected by disasters, regardless of attempts to dispel these myths (2,3,7).
Displacement: Primary Concern
The risk for communicable disease transmission after disasters is associated primarily with the size and characteristics of the population displaced, specifically the proximity of safe water and functioning latrines, the nutritional status of the displaced population, the level of immunity to vaccine-preventable diseases such as measles, and the access to healthcare services (8). Outbreaks are less frequently reported in disaster-affected populations than in conflict-affected populations, where two thirds of deaths may be from communicable diseases (9). Malnutrition increases the risk for death from communicable diseases and is more common in conflict-affected populations, particularly if their displacement is related to long-term conflict (10).
Although outbreaks after flooding (11) have been better documented than those after earthquakes, volcanic eruptions, or tsunamis (12), natural disasters (regardless of type) that do not result in population displacement are rarely associated with outbreaks (8). Historically, the large-scale displacement of populations as a result of natural disasters is not common (8), which likely contributes to the low risk for outbreaks overall and to the variability in risk among disasters of different types.
Risk Factors for Communicable Disease Transmission
Responding effectively to the needs of the disaster-affected population requires an accurate communicable disease risk assessment. The efficient use of humanitarian funds depends on implementing priority interventions on the basis of this risk assessment.
A systematic and comprehensive evaluation should identify 1) endemic and epidemic diseases that are common in the affected area; 2) living conditions of the affected population, including number, size, location, and density of settlements; 3) availability of safe water and adequate sanitation facilities; 4) underlying nutritional status and immunization coverage among the population; and 5) degree of access to healthcare and to effective case management.
Communicable Diseases Associated with Natural Disasters
The following types of communicable diseases have been associated with populations displaced by natural disasters. These diseases should be considered when postdisaster risk assessments are performed.
Water-related Communicable Diseases
Access to safe water can be jeopardized by a natural disaster. Diarrheal disease outbreaks can occur after drinking water has been contaminated and have been reported after flooding and related displacement. An outbreak of diarrheal disease after flooding in Bangladesh in 2004 involved >17,000 cases; Vibrio cholerae (O1 Ogawa and O1 Inaba) and enterotoxigenic Escherichia coli were isolated (13). A large (>16,000 cases) cholera epidemic (O1 Ogawa) in West Bengal in 1998 was attributed to preceding floods (14), and floods in Mozambique in January–March 2000 led to an increase in the incidence of diarrhea (15).
In a large study undertaken in Indonesia in 1992–1993, flooding was identified as a significant risk factor for diarrheal illnesses caused by Salmonella enterica serotype Paratyphi A (paratyphoid fever) (16). In a separate evaluation of risk factors for infection with Cryptosporidium parvum in Indonesia in 2001–2003, case-patients were >4× more likely than controls to have been exposed to flooding (17).
The risk for diarrheal disease outbreaks following natural disasters is higher in developing countries than in industrialized countries (8,11). In Aceh Province, Indonesia, a rapid health assessment in the town of Calang 2 weeks after the December 2004 tsunami found that 100% of the survivors drank from unprotected wells and that 85% of residents reported diarrhea in the previous 2 weeks (18). In Muzaffarabad, Pakistan, an outbreak of acute watery diarrhea occurred in an unplanned, poorly equipped camp of 1,800 persons after the 2005 earthquake. The outbreak involved >750 cases, mostly in adults, and was controlled after adequate water and sanitation facilities were provided (19). In the United States, diarrheal illness was noted after Hurricanes Allison (20) and Katrina (21–23), and norovirus, Salmonella, and toxigenic and nontoxigenic V. cholerae were confirmed among Katrina evacuees.
Hepatitis A and E are also transmitted by the fecal-oral route, in association with lack of access to safe water and sanitation. Hepatitis A is endemic in most developing countries, and most children are exposed and develop immunity at an early age. As a result, the risk for large outbreaks is usually low in these settings. In hepatitis E–endemic areas, outbreaks frequently follow heavy rains and floods; the illness is generally mild and self-limited, but in pregnant women case-fatality rates can reach 25% (24). After the 2005 earthquake in Pakistan, sporadic hepatitis E cases and clusters were common in areas with poor access to safe water. Over 1,200 cases of acute jaundice, many confirmed as hepatitis E, occurred among the displaced (25). Clusters of both hepatitis A and hepatitis E were noted in Aceh after the December 2004 tsunami (26).
Leptospirosis is an epidemic-prone zoonotic bacterial disease that can be transmitted by direct contact with contaminated water. Rodents shed large amounts of leptospires in their urine, and transmission occurs through contact of the skin and mucous membranes with water, damp soil or vegetation (such as sugar cane), or mud contaminated with rodent urine. Flooding facilitates spread of the organism because of the proliferation of rodents and the proximity of rodents to humans on shared high ground. Outbreaks of leptospirosis occurred in Taiwan, Republic of China, associated with Typhoon Nali in 2001 (27); in Mumbai, India, after flooding in 2000 (28); in Argentina after flooding in 1998 (29); and in the Krasnodar region of the Russian Federation in 1997 (30). After a flooding-related outbreak of leptospirosis in Brazil in 1996, spatial analysis indicated that incidence rates of leptospirosis doubled inside the flood-prone areas of Rio de Janeiro (31).
Diseases Associated with Crowding
Crowding is common in populations displaced by natural disasters and can facilitate the transmission of communicable diseases. Measles and the risk for transmission after a natural disaster are dependent on baseline immunization coverage among the affected population, and in particular among children <15 years of age. Crowded living conditions facilitate measles transmission and necessitate even higher immunization coverage levels to prevent outbreaks (32). A measles outbreak in the Philippines in 1991 among persons displaced by the eruption of Mt. Pinatubo involved >18,000 cases (33). After the tsunami in Aceh, a cluster of measles involving 35 cases occurred in Aceh Utara district, and continuing sporadic cases and clusters were common despite mass vaccination campaigns (26). In Pakistan, after the 2005 South Asia earthquake, sporadic cases and clusters of measles (>400 clinical cases in the 6 months after the earthquake) also occurred (25).
Neisseria meningitidis meningitis is transmitted from person to person, particularly in situations of crowding. Cases and deaths from meningitis among those displaced in Aceh and Pakistan have been documented (25,26). Prompt response with antimicrobial prophylaxis, as occurred in Aceh and Pakistan, can interrupt transmission. Large outbreaks have not been recently reported in disaster-affected populations but are well-documented in populations displaced by conflict (34).
Acute respiratory infections (ARI) are a major cause of illness and death among displaced populations, particularly in children <5 years of age. Lack of access to health services and to antimicrobial agents for treatment further increases the risk for death from ARI. Risk factors among displaced persons include crowding, exposure to indoor cooking using open flame, and poor nutrition. The reported incidence of ARI increased 4-fold in Nicaragua in the 30 days after Hurricane Mitch in 1998 (35), and ARI accounted for the highest number of cases and deaths among those displaced by the tsunami in Aceh in 2004 (26) and by the 2005 earthquake in Pakistan (25).
Vectorborne Diseases
Natural disasters, particularly meteorologic events such as cyclones, hurricanes, and flooding, can affect vector-breeding sites and vectorborne disease transmission. While initial flooding may wash away existing mosquito-breeding sites, standing water caused by heavy rainfall or overflow of rivers can create new breeding sites. This situation can result (with typically some weeks’ delay) in an increase of the vector population and potential for disease transmission, depending on the local mosquito vector species and its preferred habitat. The crowding of infected and susceptible hosts, a weakened public health infrastructure, and interruptions of ongoing control programs are all risk factors for vectorborne disease transmission (36).
Malaria outbreaks in the wake of flooding are a well-known phenomenon. An earthquake in Costa Rica’s Atlantic Region in 1991 was associated with changes in habitat that were beneficial for breeding and preceded an extreme rise in malaria cases (37). Additionally, periodic flooding linked to El Niño–Southern Oscillation has been associated with malaria epidemics in the dry coastal region of northern Peru (38).
Dengue transmission is influenced by meteorologic conditions, including rainfall and humidity, and often exhibits strong seasonality. However, transmission is not directly associated with flooding. Such events may coincide with periods of high risk for transmission and may be exacerbated by increased availability of the vector’s breeding sites (mostly artificial containers) caused by disruption of basic water supply and solid waste disposal services. The risk for outbreaks can be influenced by other complicating factors, such as changes in human behavior (increased exposure to mosquitoes while sleeping outside, movement from dengue-nonendemic to -endemic areas, a pause in disease control activities, overcrowding) or changes in the habitat that promote mosquito breeding (landslide, deforestation, river damming, and rerouting of water).
Other Diseases Associated with Natural Disasters
Tetanus is not transmitted person to person but is caused by a toxin released by the anaerobic tetanus bacillus Clostridium tetani. Contaminated wounds, particularly in populations where vaccination coverage levels are low, are
Cyclone Tauktae made landfall in Gujurat with sustained winds of 165 km/h
The Associated Press
Posted: 3 Hours Ago
Last Updated: 2 Hours Ago
India Cyclone
A woman wearing a mask walks through a waterlogged street in Mumbai, India, on Monday. (Rafiq Maqbool/The Associated Press)
A powerful cyclone that emerged in the Arabian Sea made landfall on India's western coast on Monday, hours after authorities evacuated hundreds of thousands of people and suspended COVID-19 vaccinations in one state.
Cyclone Tauktae, the most powerful storm to hit the region in more than two decades, came ashore in Gujarat state with heavy rain, a battering storm surge and sustained winds of up to 165 kilometres per hour, the India Meteorological Department said.
Forecasters warned of possible extensive damage from high winds, heavy rainfall and flooding in low-lying areas.
ADVERTISEMENT
Twelve people were reported dead before the storm hit land and hundreds of thousands were evacuated, a process complicated by the coronavirus pandemic.
The massive storm came as India is battling a devastating coronavirus surge — and both the storm and the virus could exacerbate the effects of the other. The storm had already led to the suspension of some vaccination efforts and there is greater risk of virus transmission in crowded evacuation shelters.
India Cyclone
A bus was half submerged by rains from Cyclone Tauktae. Authorities raced to evacuate hundreds of thousands of people and suspended COVID-19 vaccinations in Gujurat ahead of the storm. (Rafiq Maqbool/The Associated Press)
COVID-19 vaccinations suspended
In Gujarat, vaccinations were suspended for two days and authorities worked to evacuate hundreds of thousands of people to temporary relief shelters. The state's chief minister, Vijay Rupani, asked officials to ensure that oxygen supplies for hospitals are not disrupted.
In Maharashtra, six people were killed, the Press Trust of India news agency reported. The state's capital, Mumbai, was lashed by heavy rain and strong winds, forcing authorities to suspend operations at the city's main airport.
Fishing boats off the coast in both states returned to harbour and thousands of rescue and relief teams, along with ships and aircraft, were deployed for recovery operations.
India Cyclone
Fishermen try to move a fishing boat to a safer ground on the Arabian Sea coast in Mumbai on Tuesday ahead of Cyclone Tauktae. (Rafiq Maqbool/The Associated Press)
Rain from the storm earlier killed six people in Kerala, Karnataka and Goa states over the weekend before it moved along the western coastline.
ADVERTISEMENT
Virus lockdown measures, meanwhile, could slow relief work after the storm, and damage from the storm could destroy roads and cut vital supply lines for vaccines and medical supplies needed for virus patients. The damage is also likely to particularly hurt the poor, who are already stretched to the limit by the economic impact of the virus.
Popularity crumbles for Indian PM Modi as devastating COVID-19 surge continues
COVID-19 battle puts India's government on 'war footing'
The South Asia head of the International Federation of Red Cross and Red Crescent Societies, Udaya Regmi, said the cyclone is a "terrible double blow" for families that have already been hit by COVID-19 infections and deaths.
"The potential impacts of Cyclone Tauktae are frightening as this monster storm threatens the state of Gujarat. Every effort must continue to keep people safe from this dangerous storm and the raging pandemic," Regmi said.
India's western coast is no stranger to devastating cyclones, but changing climate patterns have caused them to become more intense, rather than more frequent.
In May 2020, nearly 100 people died after Cyclone Amphan, the most powerful storm to hit eastern India in more than a decade, ravaged the region and left millions without power.
India cyclone
(CBC News)
Epidemics after Natural Disasters
John T. Watson, Michelle Gayer, and Maire A. Connolly
Additional article information
Associated Data
Supplementary Materials
Abstract
The relationship between natural disasters and communicable diseases is frequently misconstrued. The risk for outbreaks is often presumed to be very high in the chaos that follows natural disasters, a fear likely derived from a perceived association between dead bodies and epidemics. However, the risk factors for outbreaks after disasters are associated primarily with population displacement. The availability of safe water and sanitation facilities, the degree of crowding, the underlying health status of the population, and the availability of healthcare services all interact within the context of the local disease ecology to influence the risk for communicable diseases and death in the affected population. We outline the risk factors for outbreaks after a disaster, review the communicable diseases likely to be important, and establish priorities to address communicable diseases in disaster settings.
Keywords: Disasters, epidemiology, outbreaks, surveillance, risk assessment, communicable diseases, perspective
Natural disasters are catastrophic events with atmospheric, geologic, and hydrologic origins. Disasters include earthquakes, volcanic eruptions, landslides, tsunamis, floods, and drought. Natural disasters can have rapid or slow onset, with serious health, social, and economic consequences. During the past 2 decades, natural disasters have killed millions of people, adversely affected the lives of at least 1 billion more people, and resulted in substantial economic damages (1). Developing countries are disproportionately affected because they lack resources, infrastructure, and disaster-preparedness systems.
Deaths associated with natural disasters, particularly rapid-onset disasters, are overwhelmingly due to blunt trauma, crush-related injuries, or drowning. Deaths from communicable diseases after natural disasters are less common.
Dead Bodies and Disease
The sudden presence of large numbers of dead bodies in the disaster-affected area may heighten concerns of disease outbreaks (2), despite the absence of evidence that dead bodies pose a risk for epidemics after natural disasters (3). When death is directly due to the natural disaster, human remains do not pose a risk for outbreaks (4). Dead bodies only pose health risks in a few situations that require specific precautions, such as deaths from cholera (5) or hemorrhagic fevers (6). Recommendations for management of dead bodies are summarized in the Table.
Table
Table
Principles for management of dead bodies*
Despite these facts, the risk for outbreaks after disasters is frequently exaggerated by both health officials and the media. Imminent threats of epidemics remain a recurring theme of media reports from areas recently affected by disasters, regardless of attempts to dispel these myths (2,3,7).
Displacement: Primary Concern
The risk for communicable disease transmission after disasters is associated primarily with the size and characteristics of the population displaced, specifically the proximity of safe water and functioning latrines, the nutritional status of the displaced population, the level of immunity to vaccine-preventable diseases such as measles, and the access to healthcare services (8). Outbreaks are less frequently reported in disaster-affected populations than in conflict-affected populations, where two thirds of deaths may be from communicable diseases (9). Malnutrition increases the risk for death from communicable diseases and is more common in conflict-affected populations, particularly if their displacement is related to long-term conflict (10).
Although outbreaks after flooding (11) have been better documented than those after earthquakes, volcanic eruptions, or tsunamis (12), natural disasters (regardless of type) that do not result in population displacement are rarely associated with outbreaks (8). Historically, the large-scale displacement of populations as a result of natural disasters is not common (8), which likely contributes to the low risk for outbreaks overall and to the variability in risk among disasters of different types.
Risk Factors for Communicable Disease Transmission
Responding effectively to the needs of the disaster-affected population requires an accurate communicable disease risk assessment. The efficient use of humanitarian funds depends on implementing priority interventions on the basis of this risk assessment.
A systematic and comprehensive evaluation should identify 1) endemic and epidemic diseases that are common in the affected area; 2) living conditions of the affected population, including number, size, location, and density of settlements; 3) availability of safe water and adequate sanitation facilities; 4) underlying nutritional status and immunization coverage among the population; and 5) degree of access to healthcare and to effective case management.
Communicable Diseases Associated with Natural Disasters
The following types of communicable diseases have been associated with populations displaced by natural disasters. These diseases should be considered when postdisaster risk assessments are performed.
Water-related Communicable Diseases
Access to safe water can be jeopardized by a natural disaster. Diarrheal disease outbreaks can occur after drinking water has been contaminated and have been reported after flooding and related displacement. An outbreak of diarrheal disease after flooding in Bangladesh in 2004 involved >17,000 cases; Vibrio cholerae (O1 Ogawa and O1 Inaba) and enterotoxigenic Escherichia coli were isolated (13). A large (>16,000 cases) cholera epidemic (O1 Ogawa) in West Bengal in 1998 was attributed to preceding floods (14), and floods in Mozambique in January–March 2000 led to an increase in the incidence of diarrhea (15).
In a large study undertaken in Indonesia in 1992–1993, flooding was identified as a significant risk factor for diarrheal illnesses caused by Salmonella enterica serotype Paratyphi A (paratyphoid fever) (16). In a separate evaluation of risk factors for infection with Cryptosporidium parvum in Indonesia in 2001–2003, case-patients were >4× more likely than controls to have been exposed to flooding (17).
The risk for diarrheal disease outbreaks following natural disasters is higher in developing countries than in industrialized countries (8,11). In Aceh Province, Indonesia, a rapid health assessment in the town of Calang 2 weeks after the December 2004 tsunami found that 100% of the survivors drank from unprotected wells and that 85% of residents reported diarrhea in the previous 2 weeks (18). In Muzaffarabad, Pakistan, an outbreak of acute watery diarrhea occurred in an unplanned, poorly equipped camp of 1,800 persons after the 2005 earthquake. The outbreak involved >750 cases, mostly in adults, and was controlled after adequate water and sanitation facilities were provided (19). In the United States, diarrheal illness was noted after Hurricanes Allison (20) and Katrina (21–23), and norovirus, Salmonella, and toxigenic and nontoxigenic V. cholerae were confirmed among Katrina evacuees.
Hepatitis A and E are also transmitted by the fecal-oral route, in association with lack of access to safe water and sanitation. Hepatitis A is endemic in most developing countries, and most children are exposed and develop immunity at an early age. As a result, the risk for large outbreaks is usually low in these settings. In hepatitis E–endemic areas, outbreaks frequently follow heavy rains and floods; the illness is generally mild and self-limited, but in pregnant women case-fatality rates can reach 25% (24). After the 2005 earthquake in Pakistan, sporadic hepatitis E cases and clusters were common in areas with poor access to safe water. Over 1,200 cases of acute jaundice, many confirmed as hepatitis E, occurred among the displaced (25). Clusters of both hepatitis A and hepatitis E were noted in Aceh after the December 2004 tsunami (26).
Leptospirosis is an epidemic-prone zoonotic bacterial disease that can be transmitted by direct contact with contaminated water. Rodents shed large amounts of leptospires in their urine, and transmission occurs through contact of the skin and mucous membranes with water, damp soil or vegetation (such as sugar cane), or mud contaminated with rodent urine. Flooding facilitates spread of the organism because of the proliferation of rodents and the proximity of rodents to humans on shared high ground. Outbreaks of leptospirosis occurred in Taiwan, Republic of China, associated with Typhoon Nali in 2001 (27); in Mumbai, India, after flooding in 2000 (28); in Argentina after flooding in 1998 (29); and in the Krasnodar region of the Russian Federation in 1997 (30). After a flooding-related outbreak of leptospirosis in Brazil in 1996, spatial analysis indicated that incidence rates of leptospirosis doubled inside the flood-prone areas of Rio de Janeiro (31).
Diseases Associated with Crowding
Crowding is common in populations displaced by natural disasters and can facilitate the transmission of communicable diseases. Measles and the risk for transmission after a natural disaster are dependent on baseline immunization coverage among the affected population, and in particular among children <15 years of age. Crowded living conditions facilitate measles transmission and necessitate even higher immunization coverage levels to prevent outbreaks (32). A measles outbreak in the Philippines in 1991 among persons displaced by the eruption of Mt. Pinatubo involved >18,000 cases (33). After the tsunami in Aceh, a cluster of measles involving 35 cases occurred in Aceh Utara district, and continuing sporadic cases and clusters were common despite mass vaccination campaigns (26). In Pakistan, after the 2005 South Asia earthquake, sporadic cases and clusters of measles (>400 clinical cases in the 6 months after the earthquake) also occurred (25).
Neisseria meningitidis meningitis is transmitted from person to person, particularly in situations of crowding. Cases and deaths from meningitis among those displaced in Aceh and Pakistan have been documented (25,26). Prompt response with antimicrobial prophylaxis, as occurred in Aceh and Pakistan, can interrupt transmission. Large outbreaks have not been recently reported in disaster-affected populations but are well-documented in populations displaced by conflict (34).
Acute respiratory infections (ARI) are a major cause of illness and death among displaced populations, particularly in children <5 years of age. Lack of access to health services and to antimicrobial agents for treatment further increases the risk for death from ARI. Risk factors among displaced persons include crowding, exposure to indoor cooking using open flame, and poor nutrition. The reported incidence of ARI increased 4-fold in Nicaragua in the 30 days after Hurricane Mitch in 1998 (35), and ARI accounted for the highest number of cases and deaths among those displaced by the tsunami in Aceh in 2004 (26) and by the 2005 earthquake in Pakistan (25).
Vectorborne Diseases
Natural disasters, particularly meteorologic events such as cyclones, hurricanes, and flooding, can affect vector-breeding sites and vectorborne disease transmission. While initial flooding may wash away existing mosquito-breeding sites, standing water caused by heavy rainfall or overflow of rivers can create new breeding sites. This situation can result (with typically some weeks’ delay) in an increase of the vector population and potential for disease transmission, depending on the local mosquito vector species and its preferred habitat. The crowding of infected and susceptible hosts, a weakened public health infrastructure, and interruptions of ongoing control programs are all risk factors for vectorborne disease transmission (36).
Malaria outbreaks in the wake of flooding are a well-known phenomenon. An earthquake in Costa Rica’s Atlantic Region in 1991 was associated with changes in habitat that were beneficial for breeding and preceded an extreme rise in malaria cases (37). Additionally, periodic flooding linked to El Niño–Southern Oscillation has been associated with malaria epidemics in the dry coastal region of northern Peru (38).
Dengue transmission is influenced by meteorologic conditions, including rainfall and humidity, and often exhibits strong seasonality. However, transmission is not directly associated with flooding. Such events may coincide with periods of high risk for transmission and may be exacerbated by increased availability of the vector’s breeding sites (mostly artificial containers) caused by disruption of basic water supply and solid waste disposal services. The risk for outbreaks can be influenced by other complicating factors, such as changes in human behavior (increased exposure to mosquitoes while sleeping outside, movement from dengue-nonendemic to -endemic areas, a pause in disease control activities, overcrowding) or changes in the habitat that promote mosquito breeding (landslide, deforestation, river damming, and rerouting of water).
Other Diseases Associated with Natural Disasters
Tetanus is not transmitted person to person but is caused by a toxin released by the anaerobic tetanus bacillus Clostridium tetani. Contaminated wounds, particularly in populations where vaccination coverage levels are low, are
