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close this bookEmergency Vector Control after Natural Disaster (PAHO)
close this folderPart I: An Overview
View the documentChapter 1: The general problem
View the documentChapter 2: Disaster preparedness
Open this folder and view contentsChapter 3: Postdisaster action
View the documentChapter 4: Vector and Rodent Related Diseases

Chapter 1: The general problem

Although there are a number of' types of' natural disasters, the scope of this ,guide will be limited to those of hurricanes, cyclones, floods, earthquakes and volcanic eruptions. In each ease, the rapidly changing environment produces a general disruption of pasterns of life, which results in stress to individuals and the weakening of' health throughout the population. In many instances, people arc forced into crowded, unsanitary conditions which can lead to outbreaks of' epidemic diseases.

For the public health administrator, sanitarian, entomologist, epidemiologist and vetctor control specialist, the management of health relief' and related responsibilities involves careful planning. Certain natural disasters may provide sufficient warning that some of' their consequences can be alleviated. Predisaster planning, consisting of' the establishment of disaster readiness committees and the formulation of' contingency plans, can limit the risk. This is accomplished through organized preparedness, including the assignment of' responsibilities to specific individuals and the establishment of' intergovernmental relationships through which better use is made of' any existing resources. Contingency planning should, however, be broad enough in scope to allow the response to be flexible. Too much detail may be counterproductive and self-defeating. Certain guides cited in the bibliography provide administrative procedures for planning and organizing public health activities during and following disasters.

'The majority of' vector control programs have static, inflexible administrative procedures. Consequently, there is a tendency to respond routinely to disaster situations, even when they call for innovation and flexibility. A disaster contingency plan may alleviate some, but not all of this problem. As a result, there may be some misdirection, confusion and waste, regardless of' how well organized and adaptable the program is. Overreaction to actual and potential risks of' vector-borne disease may occur because of' our inevitable inability to predict the actual future needs. That this is inevitable should be recognized in determining the availability of resources and the most effective use that may be made of them. In many cases the confusion and overreaction that takes place in the aftermath of a natural disaster will be partially offset by the visibility of entomology and rodent evaluation and control teams, whose presence may benefit the population psychologically.

The life history of Aedes aegypti.

Courtesy Dr. M Giglioli, Cayman Islands

Disasters do not generate "new" diseases but, by altering the environment, they may increase transmission of diseases that already exist in a region through:

(1) Direct effect of the physical event itself, such as fecal contamination
(2) Indirect effects which result in such conditions as overcrowding and poor sanitation
(3) Promoting or causing increase in the movement of populations
(4) Disrupting routine vector control programs
(5) Altering the distribution vector species.

Aedes aegypti breeding sites.

Courtesy Dr. M. Giglioli, Cayman Islands

The increased risk of transmission of vector-borne disease must be seriously considered after all natural disasters. It is a matter of priority, therefore, that the potential of transmission of vector-borne disease is assessed early in the postdisaster period. It is important to note, however, that natural disasters do not necessarily lead to outbreaks of infectious diseases. This is particularly true of the mosquito-borne diseases, since the larval habitats and adult resting sites of mosquitoes often suffer from wind and water damage. As a result, such diseases as malaria, dengue and encephalitis may not appear until several weeks after the disaster, if they appear at all.