Infectious Process, Infectious Disease, Classification Flashcards
Definition of Infectious process:
Dynamic process of interaction between susceptible macroorganisms and pathogenic microbe (etiological agent)
-includes origination, development and end of pathological conditions in host (macroorganism)
What dose Infectious processes depend on:
- Presence of pathogenic microbe
- Way of shedding (from one to another)
- Presence of susceptible macroorganism
Infection is expressed:
In a form of infectious disease
Infectious diseases cause:
- Functional and organic damage of the macroorganism
- Mobilisation of defence mechanisms
- Stages (disease), clinical picture and mass occurrence
What are Etiological agents:
- Pathogenic bacteria
- Pathogenic fungi
- Viruses and Prions
Etiological agents are able to:
- Penetrate into susceptible macroorganism
- Cause infectious process
- Be excreted into environment
- Be transmitted to the next susceptible individuals
What is Pathogenicity:
The genetic ability of a microbe to cause infectious process in a susceptible macroorganism
What is the division of Etiological agents according to pathogenicity:
- Obligatory pathogen = always cause infectious disease
- Facultative pathogen = only under some condition cause disease
- Apathogenic = not able to cause infectious disease
Pathogenicity of agents depend on:
- Their ability to survive
1. Infectivity (capability to enter, survive and multiply within host)
2. Adaptability
3. Selectivity
4. Reproducibility
5. Heritability
6. Immunogenicity
7. Transmissibility (contagious, non-contagious)
What are the factors of virulence:
- Adhesins
- Toxin
- Enzyme
- Tenacity (temperature, light, humidity, pH)
What is Tropism of pathogens (etiological agents):
Their tendency to infect organ or systems
* Monotropic = one organ or system
* Polytropic = more than one organ or system
* Pantropic = multiple sites in the organism
What are the ways of entry of the pathogen (infectious process):
- Alimentary tract (GIT - Ingestion)
- Respiratory tract (Inhalation)
- Skin (dermal)
- Urogenital tract
- Mammary gland (lactogenic infection)
- Conjunctiva
- Umbilical infection
- Accidental entry
What are the stages of infectious process:
- Incubation period (from exposure to clinical signs)
- Prodromal period (unspecific clinical signs)
- Manifestation period (specific clinical signs)
- Final period (recovery or death)
What are the forms of infectious process according to duration:
- Peracute - short time
- Acute - few days to two weeks
- Subacute - two weeks to one month
- Subchronic - few months
- Chronic - many months
What are the forms of infectious process according to its manifestation:
- Apparent
- Abortive
- Inapparent
- Latent
What are the classification of animal infection according to Hosts:
- Zoological class
- Animal category
- Number of susceptible species (Monohostal, polyhostal)
- Transmissibility to man
- Transmissibility to newborn animals (congenital, hereditary)
What are the classification of animal infection according to Etiological agents:
- Biological criteria (virus, bacteria,…)
- Origin of etiological agent (endogenous, exogenous,…)
- Contagiosity
- Quantity of agent species (monoetiological, polyetiological, multifactorial)
- Agents participation (primary, secondary infection)
- Interaction with the macroorganisms (re-infection, superinfection, recurrent infection, intercurrent infection)
Animal infections can be classified according to:
- Hosts
- Etiological agents
- Mechanisms of transmission
- Portal of entry
- Localisation in organs or systems
What is Epizootic process:
Biological, dynamic and multifactorial phenomenom based on the continous interaction among animal population, etiological agents and environment
What is the Epizootiological Chain:
It is based on the circulation of etiological agents in animal population, repeating and continuing process of etiological agent transmission among susceptible hosts
What are the stages of Epizootic Process: (6)
- Interepizootic stage ( from post to epizootic process activation)
- Preepizootic stage (population specific immunity is reduced)
- Ascending stage
- Culmination stage
- Descending stage
- Postepizootic stage
What are the Forms of epizootic process: (3)
- Apparent = typical, atypical, abortive
- Inapparent
- Latent
What are the Grades of epizootic process: (4)
- Sporadic (occurs irregularly)
- Enzootic (continuously present in a population or area longer)
- Epizootic (excess of normal expectancy in a population or area)
- Panzootic (occurs over wide area and affects large part of population)
