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Environment and gastro-enteritis
Abstract:
Pathologists are always tempted to account for the occurrence of diseases by the presence or absence of some specific microbiological agent. It is the case when a major infectious agent is in contact with a receptive animal. When the Transmissible Gastro-enteritis virus is introduced into a susceptible herd, the results of the infection are calamitious. Nevertheless, the relationship between the infection and the disease is rarely simple. It is necessary to distinguish two kinds of diseases: --the monofactorial diseases (T.G.E....) --the multifactorial diseases (Colibacillosis especially after the weaning...). For these multifactorial diseases the clinical signs and the lesions are induced by an infectious agent which can be considered as a final "effector" whose multiplication depends on factors in the farm which disturb physiological or immunological mechanisms of regulation (humoral immunity, clearance, intestinal motility...). The herd system can be defined by 6 variables which could be considered as limiting factors responsible for the onset of digestive disorders: food, building, management, animal with specific and non-specific resistance, microbism and the farmer who plays a main role in the control of these variables. The disease has to be considered not only as the result of the multiplication of the microbe which is often the last actor of a morbid process but also as the disharmony of the variables defining the structure of the herd.
Insights
Diseases are often multifactorial, not just caused by a single microbe. Farm management factors like food, building, and farmer control significantly influence animal health and disease onset.
Area of Science:
- Veterinary Pathology
- Animal Husbandry
- Infectious Disease Epidemiology
Background:
- Pathologists often attribute diseases solely to specific microbiological agents.
- The relationship between infection and disease manifestation is complex and rarely straightforward.
- Distinction between monofactorial diseases (e.g., Transmissible Gastroenteritis virus) and multifactorial diseases is crucial.
Purpose of the Study:
- To differentiate between monofactorial and multifactorial diseases in animal populations.
- To identify the contributing factors in multifactorial diseases beyond the primary infectious agent.
- To understand the herd system's role in regulating disease onset.
Main Methods:
- Analysis of disease etiology, distinguishing between single-agent and multiple-factor causation.
- Identification of farm-specific variables influencing disease development.
- Examination of the herd system as a complex interplay of factors.
Main Results:
- Multifactorial diseases involve an infectious agent as a final effector, but its multiplication is influenced by environmental and physiological factors.
- Six key variables (food, building, management, animal resistance, microbism, farmer) significantly impact digestive disorders.
- Disease is viewed as a disruption of the herd system's balanced variables, not solely microbial multiplication.
Conclusions:
- Multifactorial diseases result from a disharmony in herd system variables, with the infectious agent often being the final trigger.
- Effective disease control requires managing the interplay of environmental, physiological, and management factors within the herd.
- The farmer plays a pivotal role in controlling these variables to prevent disease outbreaks.