Non immunological resistance to Virus Infection

Non immunological resistance

Genetic Factors:

Species

Breed:

Strain:

Physiological factors

Young Animals

Nutritional status

Stress factors

Anatomical factors

Genetic Factors:

Species

 Absolute resistance (eg. Horses for FMD, Cats for CDV )

Relative  resistance (Reservoir Host); some species carries the viral infection without clinical symptoms (eg. Rabies virus in vampire bats (

Breed:

Some breeds are more susceptible to diseases than others( eg. Blue tongue virus is fatal in European sheep than Local breeds).

Strain:

Some strains of chickens are more susceptible than others (eg . Avian leucosis virus )

Physiological factors

Young Animals are more susceptible to viral diseases than older due to:

A . MQ are not yet active

B. poor interferon production

C. have active dividing cells that support virus  replication.

Nutritional status:   Deficiency in Vit., C,E,Zink and Selenium leads to less immune response to viral diseases

Stress factors: Long transport and crowding make animals  more susceptible to viral dis.( eg  BVD,IBR,PI3.)   Cortisone is an immunosuppressive factor

Harsh seasons, Chemicals, pollution some  viruses and bacteria.

Anatomical factors:   Skin, respiratory system, mucous, enzymes (Lysozymes)      .gastric juice etc….