Epidemiological Surveillance After Natural Disasters Biology Essay

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The until of 1850 and further the era of science, there were the happening of famines, epidemic and disruption of social society and the causes of major diseases due to the famine & epidemics.The natural disaster & communicable diseases relationship is commonly misconstrued. After the natural disaster the risk of an outbreak is very high.The population displacement is a very high risk factor of an outbreak after the disasters. The risk of communicable disease which effect the population are the unavailability of safe water & sanitation facilities, the degree of crowding, underlying health status of population and unavailability of health care services causes the spread of disease.The communicable diseases which occur due to the natural disasters have been eliminated due to the advances in the economic condition, industrialized societies & public health. However in the developing countries the communicable diseases are present after the disasters. The disease which spread after disaster are many for example measles, poliomyelitis, malaria, typhoid fever arthropod borne viral disease such as dengue & yellow fever. To control the communicable disease the national authorities ask for the agencies for controlling the diseases.

Natural Disaster : The natural disasters are catastrophic events with atmospheric, geologic & hydrologic origin Disasters include such as the earthquakes, volcanic eruption, landslides, tsunamis, floods & drought. The natural disasters can have rapid or slow onset with serious health, social and economic consequences.

Epidemiology : The epidemiology is the study of patteren disease in populations and of factors that determine its occurance. Veterinary epidemiology includes investigation and assessment of other health related events notable productivity. All of these investigation involve observing animal population and making inferences from the observation.

Factor of disease transmission after disaster

There are the different types of adverse changes that cause the potential risk of the communicable diseases. The changes which cause the transmission of diseases are changes in the ecology after disaster these are displacement of population, population density changes, disruption the public utilities and interruption in public health services. The factors which cause the transmission of disease after the disaster are given below.

Ecological changes

Displacement of population

Displacement of population

Interruption of basic public health services

Displacement of domestic and wild animals.

Public utilities disruption

Dead Bodies

Ecological changes: The natural disaster which are the drought, flood & hurricanes these produce the ecological changes in environment which cause the increase in the risk of the communicable disease. The most significantly affected disease are the vector borne & water borne diseases.

The rain due to the hurricane which causes the flooding of the streams & canals in the rural area also is the source of drinking water because of which the water borne disease which are zoonotic for example the leptospirosis is spread due to the drinking of the contaminated water.

Displacement of population: The population which is affected due to the risk of communicable diseases spread by disaster from affected area which are the 3 possible ways. If the population move to the nearby place the facilities & services in that community will be strained. When the population move to a distance the increase of chances to encounter the disease that is not prevalent in their community which are susceptible.

Density of population: The density of the population is very critical factor for the transmission of disease which is spread through respiratory route and animal to animal contact. Due the destruction of houses the natural disaster cause to increase in population density. Due to the increase in the density of the population in the area the risk of the increase in the spread of air borne disease including the influenza & non specific diarrheas.

Interruption of basic public health services: The basic public health services are interrupted such as vaccination, treatment of tuberculosis & the programs for the controlling of the malaria and the vector are interrupted which cause the transmission of disease after disaster. The transmission of disease risk increase to the extent of duration of disruption. The outbreak of the communicable disease occur months or year due to the famine or civil disturbance. The interruption is usually the result of diversion of staff & financial resources to relief endeavor.

Displacement of domestic and wild animals: Due to the natural disaster the human & animal population are displaced which carry the zoonotic diseases that transmitted to humans and other animals.

Public utilities disruption: After the disaster the public utilities are disrupted which are the electricity, water, sewage disposal and also not supply of the proper feed to the animals. After the disaster the animals are held together & their waste materials is not handle properly and provide the water which is contaminated which is the source of the communicable diseases. The feed provide to the animals is contaminated and the source of fungus and other germs which causes the disease to the animals.

Dead Bodies: Due to the natural disaster there are the presence of large No. of dead bodies in that disaster affected area. Which are the high risk of the disease outbreak.

In some diseases the infectious agent is the main determinants and host & environmental factors are of the relatively minor importance. Such diseases for example foot-and-mouth disease and rinderpest occurring in susceptible populations.

Figure 1: The "tried": three main headings under which determinants can be classified

Communicable Diseases Associated with Natural Disasters

Water-related Communicable Diseases

Diarrheal disease outbreaks


Vectorborne Diseases

Malaria outbreaks

Dengue fever transmission

Viral encephalitis

Other Diseases Associated with Natural Disasters


Outbreak of coccidiomycosis




The continuous investigation of a given population to detect the occurrence of disease for control purpose, which may involve testing of part of a population.

Goals of surveillance

The broad aims of veterinary surveillance follow the goals of veterinary medicine in general namely maintenance of high standards of animal health and welfare and the protection of public health. Several specific objectives can be identified:

Rapid detection of disease outbreaks.

Early identification of disease problems.

Assessment of the health status of a defined population.

The disease control and prevention.

Identification of new and emerging diseases.

Confirmation of absence of a specific disease.

Information Flow in Disease Surveillance

Sources of data

The organization and groups described below represent a comprehensive list of possible sources for surveillance and other types of epidemiological investigation. Some organization record and store data routinely and therefore provide structure collections of data and information system to which reference can be made for surveillance activities and when mounting other epidemiological studies.

Government veterinary organization

These services investigate disease of national importance particularly those infectious ones for which legislation enforces reporting. Many governments also operate diagnostic laboratories. Reports are sometimes prepared and published routinely.

Veterinary practices

The private veterinary practitioners have contact with farm and companion animals. Farm animal veterinarians have the greatest contact with dairy cattle and other animals.The owner of companion animals usually attend private clinics. Thus the practitioner is a major potential source of animal disease data.


The red meat abattoirs process large numbers of animals for human consumption and identify some diseases during meat inspection. Most reports relate to helminth diseases and internal lesions such as hepatic abscesses. A secondary objective is to record details of abnormalities that are found because these findings may be of epidemiological value. Abattoirs therefore can be primary sources of data for disease surveillance for condition for which other diagnostic methods are not appropriate. It is possible to conduct auxiliary investigation of blood, sputum, lymph nodes and other tissue for specific surveys and studies. Animals examined at meat inspection do not originate from the abattoir they have travelled there. Trace back is therefore desirable of the disease that are identified are to be associated with their farm or area of origin.

Poultry slaughter house

Post mortem examination results from these premises constitute another source of information.

Kancker yards

In some countries animals that are ill or have died and are therefore unfit for human consumption are sent for slaughter to premises other than abattoirs. These premises are called knacker yards. The carcasses are fed to animals such as dog. The data from knacker would require professional veterinary inspection of lesions to ensure accuracy.

Commercial livestock enterprises

Many of these enterprises have their own recording systems although again some data may be confidential. These sources have been utilized.

Farm records

Many farmers routinely record production data. Some record information on disease.

Veterinary schools

Veterinary schools have clinics that record the results of consultation. They have the data on the disease which is use for the survey.

Research laboratories

Research laboratories record data on primates, lagomorphs, rodents and cavies that are used in experiments. These sources are very specialized closed communities and therefore are obviously biased.

Serum banks

Serum samples may be collected routinely during mandatory control and eradication campaigns in which serological tests are used to diagnose infection.

Application of serum banks: serum banks can provide useful epidemiological information on infectious diseases which are

Identification of major health oribelums

Establishment of vaccination priorities.

Demarcation of the distribution of disease.

Investigation of newly discovered diseases.

Determination of epidemic periodicity.

An increase in the knowledge of disease aetiology.

Evaluation of vaccination compaings.

Assessment of economic losses due to disease.

Data collection

Data is collected in three main ways by,


Clinical examination

Diagnostic imaging

Post mortem examination

Completing questionnaires



Documentary sources

Clinical records

Record of diagnostic laboratory results

The data obtained from the first two methods are primary whereas data obtained by the third method are secondary.

Recording of data

There are the different method of recording of data which are given below.

Day book

Record card


Computerized recording techniques

Pro-formas: A per-forma is an extension of the partially closed record. It is used for the recording of the data. It is a mainly closed record, comprising a check list of many features. This can produce a very detailed record of observational and interpretative data. Completion of all components of the records. Per-formas should always have an open section to accommodate any salient details that are not included in the closed part.

Figure 2: An example of a clinical case record pro-forma.

Sending of Sample to Laboratory

After the collection of the data disease is diagnose according to the signs/symptoms. If there is confusion in the diagnose of the different diseases the sample is collected and sent to the laboratory for confirmation of the disease. You also send all the information about the veterinarian who sending the sample, about animal, about sample and all other relevant information. The general guidelines about the submission of sample to the lab are given below.

Label the tube or syringe with unique patient identification and case investigation.

Transport in upright and secured in screw cap container or in transport box or rack.

Transport as soon as possible.

Transport bacterial sample at ambient temperature and viruses at 48 C.

Sample should reach to laboratory within 24 hours.

Figure 3: Per-forma of information about sample to sending Lab for disease diagnose.

Reporting of disease

When you confirm the disease in the disaster are with the help of clinical observation, history about the disease of the animal & Lab findings. Then you send a report about the infectious diseases to the higher authorities/Livestock department/Epidemiological unit to plan a strategy for the control measure of said infectious diseases to protect the animals of poor people of that disaster area which are the precious wealth of innocent poor people. In the report you mention brief about the area the disaster and about your plan of surveillance that conducted in that area. In the report you attach a perform which contain the information of reporting veterinarian, animal owner information, animal information, animal location, history, clinical findings, treatment, Lab result, additional comments.