Apart from localizing with precision any geographic coordinate, these systems allow for the addition to geographic map images of several layers with a great variety of geographic data –such as images detecting variables at a distance, minor roads, highways or freeways, geology, hydrology, natural or geopolitical boundaries between cities, counties, departments, regions, etc.-
This data may be voluntarily superimposed so that maps may be illustrated generating useful data for different types of industries and with great precision as regards distances.
EXACT LOCALIZATION OF FARMS
For example, all poultry farms or facilities of any geographical area may be represented in the maps within one of the many “layers” which may be illustrated on each map.
Any type of information of interest may be added to each map, such as, for example, distance between farms, distance between farms and highways or processing plants, natural barriers, etc.
TOOL FOR THE EXPERT
The resulting maps may be very useful for the expert in poultry health:
Control of avian transport and poultry products or bed material of poultry farms
Vehicle mobilization, etc.
The assessment of this data allows for the analysis in time and space in relation to prevalence of disease.
OFFICIAL CONTROL TOOL
They are also very useful for official notice and official compartmentalization of diseases in order to continue with international trade practices of birds and poultry products under certain circumstances.
Figure 1. Old map which shows the approximate location of a geographical area affected by certain respiratory disease.
Localization of farms in the epidemiological area and farms contained in said area was made by drawing them by hand.
Before the development of GIS technology, epidemiologists “drew” virtually by hand the approximate location of farms and disease outbreaks on paper maps, with inevitable countless deficiencies and inaccuracies. Those old maps which contained some information about roads, topography or geographical grids had many deficiencies and were difficult to update or handle (Figure 1).
Figure 2. GIS map: Modern map created with computer systems
– A modern map created by GIS contains the precise location of each farm, hatchery, slaughterhouse, by-product cooking plant, feed mills, etc.
– It may graphically and exactly illustrate all farms at risk, according to pre-determined criteria.
– It may contain several characteristics of interest to the epidemiologist or the expert in animal health.
The computer system is capable of measuring distances and adding multiple data layers. Furthermore, it must be capable of easily and readily analyzing information (Figure 2).
An essential requirement for the success of GIS use in poultry epidemiology is the frequent collection and updating of the exact location of poultry farms and their characteristics –such as the number of barns in the farm, its capacity, the farm’s name and the owner’s name, the zootechnical function of birds, etc.-
This information is fed into a GIS system, by expert staff and who are familiarized therewith.
In order to provide useful data, it is essential to include all the farms and other relevant poultry facilities on the maps.
Omitting one or more farms is an error, since it makes difficult to completely visualize the epidemiological area and all farms at risk of infection.
All farms from one area of interest must be included in the general information.
Thus, all companies from a particular area must consent to the geographical data centralization of each one of them, and, therefore, industry must be aware of the information usefulness.
Success in the use of GIS in epidemiology depends on the accuracy in data collection and updating
The regular data updating is equally crucial. Each company must verify that the location of each one of its facilities or farms corresponds to the described coordinates.
If farms change name or owner, or in case they are disabled, it is important to update the information. Also, information must be similarly updated if the farm’s capacity is reduced due to abandonment or if it is increased due to the farm’s growth.
Sometimes it is difficult to have the location of all the non-commercial birds in an area of interest, but they must be gradually included in the system when the information comes up.
Once all data has been verified, updated and recorded, the operator may quickly generate the relevant maps. Also, a good communication system –email for example – is the basis for a notification system and the determination of a monitoring program.
Ideally, the person operating the GIS system is a neutral, reliable person in the poultry industry, and only uses the information generated by GIS for the purposes for which the GIS system was implemented.
Boards created and represented by the poultry industry
GIS systems are extremely useful for controlling infectious respiratory diseases –avian influenza, infectious bronchitis, infectious laryngotracheitis, mycoplasmosis and infectious coryza -.
It is important to create a technical board or committee (TC) for decision-making.
The TC will represent all local industry members, it will make decisions as regards the use of GIS and will give answers for different possible disease notifications.
Poultry areas are typically very populated with farms and birds and may be very different in nature. The location of affected farms must be registered on a GIS map in relation to the rest of the farms in the area. Also, this location and nature of the disease outbreak must be reported as soon as certain important disease is diagnosed.
This information is shared with all the companies in the area in order to make easier disease control. The latter can only be achieved by means of the common agreement from the industry for notifying diseases and its location by farm and company. Unfortunately, some countries are still reluctant to disclose the presence of diseases in specific farms.
Poultry areas allowing the localization and notification of diseases tend to more rapidly and effectively control diseases.
Those areas hiding the presence of diseases or not allowing the disclosure of information tend to suffer diseases which spread uncontrollably since there is no available information about the diagnosed disease, making impossible to implement control measures common to all the affected area.
A concept, which is important to understand and remember, is that a densely populated poultry area must be considered as a sole epidemiological unit even if there are two or more competing companies in said area and in spite of any factor or impediment noticed to share the information.
The use of GIS systems for controlling diseases is impossible without having beforehand the approval from the entire local industry for the voluntary notification of diseases.
There are many examples of actions which producers may implement for controlling diseases once they have received a notification containing maps generated by GIS.
The information guardian may have published the list of farms at risk of infection and may have shared the information as a graphic. Having this information makes possible to decide to intensify biosecurity measures and insect and rodent control in farms in the area, or even visit of personnel not essential or external to the farms may be banned.
As regards affected birds, they may be sent to slaughterhouses on the days or times which reduce the risk of infection to other farms, and may be transported by roads or highways where there is less farm population and therefore, less risk of contamination in other facilities and infection in susceptible birds.
The designation of routes specially selected for this purpose is a very easy task using GIS, although it is potentially difficult and time-consuming without the GIS system.
The TC- Technical Committee- may request a list of all the farms located within a radius of 3.6 or 10 km from the initial case. Once the list and the GIS map are generated, the companies may modify, for example, either their visit routes to farms, the order of egg collection by the truck taking them to the hatchery, the routes of feed delivery in farms or the live bird transport.
The next step is to specify epidemiological areas surrounding several secondary cases or outbreaks. This information is important and necessary so that the TC may meet and discuss possible intervention measures for all farms in the area, including decisions related to live bird transport, hen droppings or chicken droppings, vaccinations, isolation, treatments, biosecurity, bird traffic, producer’s awareness and several other aspects.
These epidemiological areas are dynamic and may change dimensions and geographical form or specifically relevant areas may be designated within other areas depending on the TC decisions or to facilitate the measures applied by said TC.
There are several applications of GIS systems and they may vary depending on the type of industry, farm density and disease prevalence or infection risks
Space analysis is another very useful tool in GIS system software. For example, you may use it to analyze:
GIS maps are also useful to carry out assays in preparation for catastrophic events such as the appearance of exotic diseases, facility destruction caused by tornados, hurricanes, earthquakes or floods, or in cases of true epidemiological emergencies.
Basic criteria include:
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