8. Acquired immunity This refers to immunity provided by immune cells or antibodies that are produced in response to exposure to an antigen. These cells and proteins circulate through the body in the blood. Passive immunity- Passed from mother. Breeder should be boosted Care must be taken to vaccinate the newly hatched. Active immunity- As a result of recovery from a disease By vaccination
19. mortality up to 100% Affected birds are more susceptible to other diseases, both parasitic and bacterial. The route of infection is usually respiratory and the disease is highly contagious spread by infective feather-follicle dander, fomites, etc Signs: Paralysis of legs, wings and neck. Loss of weight. Grey iris or irregular pupil. Vision impairment. Skin around feather follicles raised and roughened.
22. Signs Sudden Death Depression. Coughing. Dyspnoea. Diarrhoea. Nervous signs. Paralysis. Twisted neck. Severe drop in egg production.
23. Treatment None, antibiotics to control secondary bacteria. Prevention Quarantine, biosecurity, all-in/all-out production, vaccination.
24. Fowl Plague Signs Sudden death. Marked loss of appetite, reduced feed consumption. Cessation of normal flock vocalisation. Drops in egg production. Depression. Coughing. Nasal and ocular discharge. Swollen face. Cyanosis of comb/wattles. Diarrhoea (often green). Nervous signs such as paralysis.
25. Treatment None, but good husbandry, nutrition and antibiotics may reduce losses. Eradication by slaughter is usual in chickens and turkeys. Prevention Hygiene, quarantine, all-in/all-out production, etc. Minimise contact with wild birds, Vaccination
26.
27. Egg Drop Syndrome Signs: Egg drop at peak or failure to peak. Drops may be of 5 to 50% and last for 3-4 weeks. Rough, thin or soft-shelled eggs and shell-less eggs. Loss of shell pigment. Poor internal quality. Lack of signs in the birds themselves.
33. Handling every bird Subcutaneous injection under the skin usually at the back of the neck and not into the muscle. Ocular Through bird’s eyes. vaccine makes its way into the respiratory tract via the lacrimal duct. Nasal Through birds’ nostrils either as a dust or as a drop. Oral given in the mouth. Cloacal to the mucus membranes of the cloaca with an abrasive applicator. The technique is not used, as a rule, on commercial farms. Feather follicle into the feather follicles Good hygiene is necessary to prevent the introduction of contaminant organisms with the vaccine. Wing stab into the wing by a special needle(s).
34. Drinking water The vaccine is added to the drinking . Take care to ensure the vaccine is administered correctly All equipment used for vaccination is carefully cleaned and free of detergents and disinfectants; Only cold, clean water of drinking quality should be used; Ensure that all birds drink during the vaccination phase, Spray The vaccine is sprayed onto the chickens (or into the air above the chickens) Handling whole group
35. monitoring Ascertain whether the vaccine has worked or “taken”. many cases the birds react approximately 5 to 7 days after vaccination by showing signs if ill health - slight cough, a higher temperature and lethargy. In cases where there are no obvious signs of success, blood samples may be taken and sent to the laboratory for examination. The usual test is for the presence of an adequate number of the appropriate antibodies (called the titre) in the blood. Failure to find evidence of success could be because of: Faulty technique resulting in the vaccine not being introduced into the vaccination site. Faulty vaccine - too old or not stored or mixed correctly. It would be unusual but not impossible for the vaccine to be faulty from manufacture. The birds are already immune i.e. the immune system has already been triggered as a result of parental (passive) immunity, previous vaccination or other exposure to the causal organism.
36. Transgenic approach Transgenic chickens were made by retroviral vectors based on avian leukemia virus (ALV) and reticuloendotheliosis (REV) (Regional Poultry Disease Laboratory in East Lansing genomes. ) Transgenic disease resistance is most likely obtained by blocking of viral receptors. Inhibition of virus replication by antisense DNA is promising for the future. Production of biomedical proteins will most likely be the first practical use of transgenic chickens. The current live-virus vaccines will be replaced by inactivated (sub-unit) vaccines and thereafter by recombinant DNA vaccines based on viral vectors