Animal Hygiene : Sources of infection

Sources of infection :                                                      

   There are many sources of infection:

1-Soil :

     Many of diseases transported via the soil like tetanus ,Anthrax ,black leg disease ,which ever is spore forming that still static in the soil for long duration may reach many years and can caused the disease when found the predisposing factors.

2-Air :

     There are a large amount of microorganisms that carried by the air and transported to healthy animals by aspirate the expiration of carrier and infected animal that carried the droplet which contain the microorganisms (Droplet infection ) like respiratory diseases e.g :T.B , Equine influenza ,swine plague ,swine influenza ,pneumonia ,Also when these infected droplet to fall upon the floor of the yards ,also when they dry and mixed with yard soil that which irritated by air flow induced different infected diseases (Dust infection) ,and when they found their way to conjunctiva of eyes or respiratory system .This way is one of infectious route which can be happened in states of microorganisms which can resistance the dryness of yards floor like T.B ,Staphylococcus and anthrax spores .While the microorganism can reach to the floor mixed with carrier and infected animals excretion (urine ,faeces ,mucous) ,then become dry and mixed with the dust that carried by the air to infected  another healthy animals ,in addition for that the air may be carried some organic material like hair ,wool ,plant fiber ,pollin grain or dry faeces ,therefore the inhalation of these matters by the animal caused congestion of mucous membrane ,then decrease its resistance and exposure animal to allergic diseases.

3-Water :

      The water play an important role for spreading the infection and main source of infection and also transport many microorganisms that causes many epidemic and infectious disease (water borne diseases) by:

A-Watering and swimming healthy animal at contaminated water with excretion of diseased animal .

B-Drainage the waste of slaughterhouses ,hospitals, plants ,yards ,in reservoirs  of water.

C-Water polluted with waste matter from outlets and drain of slaughterhouses, Veterinary hospitals , and from factories handling animal products.

4-Throwing the carcasses of animals which have dead of many diseases or where found dead into the water , then they may become the cause of new foci of infection of animals.

   4-Insect:

        The insect can be transported for many infectious disease mechanically or as mechanical factor  ,the role of housefly for transport the microorganism of T.B and Anthrax (Direct method) ,or (indirect method) the role of insect and ectoparasites for transporting blood diseases when suckled blood of infected animals or carriers ,therefore causing    the  disease by bite the healthy animals.                      

 5 -Feed:    

           The feed an important source of infection among   animals like suckling animals may be infected by T.B when  suckled infected milk from there dam ,or by feeding on contaminated feed by excretions of diseased animals or by contaminated the field with livestock manure that infected with internal parasite ,therefore the healthy animals may be infected by ingestion the eggs and larve of this parasite.

6-Direct contact:

               When contact healthy animal with diseased animal infected with dermatological disease like mange ,therefore the first will be infected by the disease ,also Brucellosis may be transported  from cow to another when contact healthy animal with vaginal discharge of diseased animal or by Bulls or Ox when mating occur.

7-Indirect contact :

      It is happen by use Grooming and Cleaning tools (body brush   )   and another equipment of both healthy and diseased animals at  same time, and therefore transport disease may be happed among animals or when transport animals by vehicles (cars) which previously transport diseased animals without cleaning and disinfection ,or due to housing healthy animal in yardspreviously housing diseased animal or dead from infectiousdisease without disinfection.

8-Carrier:

           When animal/ bird exposed to some infectious diseases and then recovered ,or incurred immunity against the disease ,but still carrier to the causative agent ,therefore it excreted with animal excretions ,then can be infected another contact animal /birds .Like Brucellosis in cattle and white diarrhea in birds.

9-Infections from free living microorganisms:

            On mucous membrane of respiratory system ,when any decrease or reduce or inhibition of body resistance for any reasons ,these microorganisms can be invated the body and penetrate this mucous membranes ,then causing the disease like Heamorrhagic septiceamia (H.S) in cattle that may be spread in summer due to decrease in animal immunity or resistance ,and increase in humidity level in weather and decrease in green feeding.