Change to English interface versionChange to French interface versionChange to Spanish interface versionHome pageClear last query resultsHelp page
Search for specific termsBrowse books by topic categoryBrowse alphabetical list of titlesBrowse books by organizationBrowse by keywords


Display all textExpand table of contentsOpen this page in a new windowDon't highlight search terms
close this bookEpidemiologic Surveillance after Natural Disaster (PAHO - OPS; 1982; 105 pages) [FR] [ES]
close this folderPart 1 : Epidemiologic surveillance and disease control after natural disaster
close this folderChapter 1 : Risk factors for communicable diseases after disasters
View the documentEpidemiologic factors that determine the potential of communicable disease transmission
View the documentThe relative risk of communicable disease after natural versus manmade disasters
View the documentPostdisaster experience with communicable disease

Postdisaster experience with communicable disease

Historically, a variety of communicable dieseases have reached epidemic proportions after disaster (4,5) or because patients are malnourished and thus more susceptible of many diesease agents (6,7). Indeed, until World War II more deaths during wartime or famine were caused by communicable disease than by hostile action or starvation. The diseases classically associated with war and famine and the most effective methods for controlling them are enumerated in Table 1. Human transmission of smallpox has now been certified to be global!! eliminated and several other conditions (i.e., louse-borne typhus, plague, and relapsing fever) have a severely limited geographic distribution, in remote and largely unpopulated areas.

World War 11 represented a transitional period for industrialized combatant countries. The five years of continual war and occupation had affected civilian populations in Europe surprisingly less than did warfare in previous conflicts. The most notable increases in disease levels were those of new cases of pulmonary tuberculosis, which rose steadily throughout Western Europe, and of reported cases of typhoid fever, the total of which doubled (8-10). Most seriously affected were displaced persons, encamped refugees and inmates of concentration camps (11-13). In marginally nourished and starving patients, typhus, dysentery, scarlet fever, and diphtheria caused sporadic outbreaks and many deaths.

Serious outbreak of communicable disease after disaster has not been documented in Western Europe, the Continental United States or Canada since 1945. This improvement is associated with generally improved sanitary conditions and with the disappearance of certain vector-borne diseases from many countries, as in the case of malaria, or the restriction of diseases to isolated areas after the development and usage of effective insecticides and pesticides. The immunization of susceptible populations with vaccines effective against diseases such as diphtheria, pertussis, tetanus, poliomyelitis and measles and the adequate treatment and interruption of transmission by antibiotics of diseases like typhoid, streptococcal diseases, and tuberculosis is also associated with the lack of serious outbreaks. In caring for populations affected by disasters in industrialized countries, physicians have observed apparent increases in nonspecific diarrhea, and influenza and minor respiratory infections. The magnitude of the problem created by these, however, is such that population density alone may adequately explain it.

The evaluation of recent experiences with communicable diseases in Latin America, the Caribbean and other parts of the developing world is complicated by several factors related to changing patterns of disease, development, and the public health infrastructure. Most important of these are the persistence of many serious communicable diseases; the decline of some serious communicable disease; a lack of base line surveillance data; the inadequate number of laboratory diagnostic facilities; and in adequate converage with vaccines.

Table 1. Communicable Diseases of Public Health Importance Classically Associated with War and Famine, with Traditional Methods of Prevention and Control (21)

Disease

A. Water and/or Food-Borne Diseases

1. Typhoid and Paratyphoid Fevers
2. Food Poisoning
3. Sewage Poisoning
4. Cholera
5. Leptospirosis

Public Health Measures

a. Adequate disposal of feces and urine.
b. Safe water for drinking and washing
c. Sanitary food preparation
d. Fly and pest control.
e. Disease surveillance.
f. Isolation and Treatment of early cases (typhoid and paratyphoid fevers, cholera).
g. Immunization (typhoid fever and cholera).

Disease

B. Person to Person Spread

Contact Diseases
1. Shigellosis
2. Nonspecific diarrheas
3. Streptococcal skin infections
4. Scabies
5. Infectious hepatitis

Public Health Measures

a. Reduced crowding.
b. Adequate washing facilities.
c. Public health education.
d. Disease surveillance in clinics.
e. Treatment of clinical cases.
f. Immunization (infectious hepatitis).

Respiratory Spread
1. Smallpox
2. Measles
3. Whooping Cough
4. Diphtheria
5. Influenza
6. Tuberculosis

Public Health Measures

a. Adequate levels of immunization before the disaster.
b. Reduced crowding.
c. Disease surveillance in clinics and community.
d. Isolation of index cases (especially smallpox).
e. Immunization of entire population (smallpox) or children (measles).
f. Continue primary immunization of infants (diphtheria, whooping cough, tetanus).

Disease

C. Vector-Borne Diseases

1. Louse-borne typhus
2. Plague (rat flea)
3. Relapsing fever
4. Malaria (mosquito)
5. Viral encephalitis

Public Health Measures

a. Disinfection (except malaria and encephalitis).
b. Vector control.
c. Disease surveillance.
d. Isolation and treatment (no isolation for malaria).

Disease

D. Wound Complications
1. Tetanus

Public Health Measures

a. Tetanus toxoid immunization.
b. Postexposure tetanus antitoxin.

Persistence of many serious communicable diseases

In spite of the rarity of documentation of outbreaks of communicable diseases after disasters in developing countries, there is a consensus that the probability of outbreak is considerably higher in Latin America and the Carribbean than it is in the U.S.A. This opinion is based upon morbidity and mortality data in which patterns of many communicable diseases are at levels comparable to those in Europe and North America at the turn of the century (14). The most revalent of these diseases are acute respiratory infection, tuberculosis, diarrhea! diseases of various etiologies and diseases which are preventable through vaccination.

Decline of some serious communicable diseases

In counterbalance to the high levels of most of the communicable diseases transmitted by person-to-person contact, in most of Latin America and the Caribbean the classical diseases associated with disasters have declined or disappeared. The Americas have also been spared the widespread severe malnutrition and recurrent famines which have afflicted Africa and Asia.

Lack of baseline surveillance data

Lack of information regarding levels of communicable diseases between disasters in developing countries makes it extremely difficult for epidemiologists to confirm subsequent reported "increases" and to attribute them to an acute event. A medical team which moves into an area without previous health services or regular disease reporting may, for example, encounter clinical cases of typhoid fever or tetanus. When this happens it is frequently difficult for field workers or relief agencies to determine if an acute public health emergency exists or whether the true level of endemic disease is finally being appreciated. The potential of epidemic levels of communicable disease after disaster and the appropriate organization of surveillance systems are the subjects of Chapters 2 and 3.

Inadequate laboratory diagnostic facilities

Documentation of communicable diseases such as typhoid or dengue fever is frequently frustrated after disasters in Latin America and the Caribbean when physicians rely exclusively on their clinical acumen to diagnose communicable diseases. This is the end result of medical curricula in which the effective use of the laboratory is not included, of poorly run microbiology laboratories in which the clinician or epidemiologist has little confidence, and of the policy of not providing adequate support to public health laboratories which are seen as too expensive, as using inappropriate technology, or as unnecessary to primary health care in developing countries.

Inadequate vaccination coverage

The probability of occurrence of vaccine-preventable diseases is related to the percentage of the population that has acquired natural immunity, and the percentage of unvaccinated susceptibles. Most of the vaccines in common use are directed against childhood diseases, such as diphtheria, pertussis, tetanus, poliomyelitis and measles. Indiscriminate or improvised vaccination programs are neither feasible nor effective in the aftermath of disaster. Therefore, the extent to which the children have completed their primary series of vaccinations before a disaster will determine the likelihood of epidemic after a disaster.

to previous section to next section

[English]  [French]  [Spanish]