poultry diseases

1. Poultry diseases
Dr. Javaria Alam

2. Gamboro/IBD
 (IBD), also known as Gumboro, is a highly contagious viral infection that is
found in chicken flocks in most countries. The severity of the disease will
depend on the age and breed of chicken
 Chickens are most susceptible to clinical disease at 3-6 weeks
 Chickens that are immunosuppressed by early IBD infections do not respond
well to vaccination and are more susceptible to other diseases, including
those that don’t normally affect healthy chickens
 Incubation of 3-4 days. Mortality is usually low but has been reported to be as
high as 20%. Recovery from the disease usually occurs in less than a week,

3. Etielogy
 Infectious bursal disease is caused by a birnavirus (IBDV) that is most readily
isolated from the bursa of Fabricius which is an organ of the immune system
 It is shed in the faeces and spreads between birds or by contact with a
contaminated environment and is possibly also carried in dust. The virus can
be transferred from house to house on fomites

4. Signs
 Sudden increase in mortality
 a rapid drop in feed and water consumption,
 mucoid (slimy) diarrhoea with soiled vent feathers, ruffled feathers,
 listless chicks with unsteady gait or sitting in hunched position,
 picking at own vent and
 sleeping with beak touching the floor.
 The bursa of Fabricius is the main organ affected, showing swelling from
edema and hemorrhage during the early stages of the disease and then
shrinking (atrophy) 7-8 days following infection.

5. Treatment
 There is no treatment for IBD but support therapies such as vitamin and
electrolyte supplements and antibiotics to treat any secondary bacterial
infections, may reduce the impact of the disease
 Prevention is through good biosecurity and vaccination

6. HPS/Angara disease
 This condition was first identified in broilers in Pakistan in 1987. It spread
rapidly in broiler producing areas in that country
 It affects mainly broilers
 It is a condition caused by an adenovirus, possibly in combination with an RNA
virus and immunosuppression caused by Chick Anaemia Virus or Infectious
Bursal Disease.
 Mortality may reach 60% but more typically 10-30%.

7. Signs
 The disease is prevalent in 3-7 week old broilers
 Characterized by its sudden onset
 accumulation of a jelly like fluid in the pericardial sac
 inflamed liver with basophilic intranuclear inclusion bodies
 congested kidneys
 and up to 70% mortality rates

8. Treatment
 None. Good water sanitation (e.g. treatment of drinking water with 0.1% of a
2.5% iodophor solution) appears to be beneficial.
 The condition typically occurs in areas of high poultry density where multi-
age operation is traditional.
 Control of predisposing immunosuppressive diseases may help limit losses.
 Formalin-inactivated oil adjuvant vaccines are reported to be highly effective
and are used in areas where the condition is endemic.

9. Avian Influenza
 Avian Influenza (AI) is a contagious viral infection which can affect all species
of birds
 The virus causing avian influenza is an Influenzavirus A virus of the family
Orthomyxoviridae
 To date only viruses of H5 and H7 subtype have been shown to cause HPAI in
susceptible species, but not all H5 and H7 viruses are highly pathogenic.

10. AI
There are many strains of AI viruses and generally can be classifi ed into two
categories:
 low pathogenic (LPAI) that typically causes little or no clinical signs in birds
and highly
 pathogenic (HPAI) that can cause severe clinical signs and/or high mortality in
birds
 The Asian origin highly pathogenic H5N1 strain of the AI virus has attracted
much attention over the last few years because of signifi cant outbreaks
globally in domestic and wild birds.

11. Transmission
 Several factors can contribute to the spread of AI viruses including
globalization and international trade (legally and illegally),
 marketing practices
 (live bird markets), farming practices
 and the presence of the viruses in wild birds. Wild birds normally can carry
avian influenza viruses in their respiratory or intestinal tracts and usually do
not get sick. Wild birds have historically been known as reservoirs

12. Transmission
 AI viruses can be spread through direct contact with secretions from infected
birds, especially feces or through contaminated feed, water, equipment and
clothing.
 Avian infl uenza viruses are readily transmitted from farm to farm by the
movement of domestic live birds, people (especially when shoes and other
clothing are contaminated), and contaminated vehicles, equipment, feed,
and cages.

13. Signs
In the mild form, signs of illness may be expressed only as ruffled feathers,
reduced egg production, or mild effects on the respiratory system.
In the severe form of the disease, the virus not only affects the respiratory
tract, as in the mild form, but also invades multiple organs and tissues that can
result in massive internal haemorrhaging.

14. Signs
 quietness and extreme depression;
 – sudden drop in production of eggs, many of
 which are soft-shelled or shell-less;
 – wattles and combs become swollen and
 congested;
 – swelling of the skin under the eyes;
 – coughing, sneezing and nervous signs;
 – diarrhoea;
 – haemorrhages on the hock;
 – a few deaths may occur over several days,
 followed by rapid spread and a mortality rate
 that can then approach 100% within 48 hours.

15. Prevention
 keep poultry away from areas frequented by wild fowl;
 keep control over access to poultry houses by people and equipment;
 do not provide elements on property that may attract wild birds;
 maintain sanitation of property, poultry houses and equipment;
 avoid the introduction of birds of unknown disease status into flock;
 report illness and death of birds
 appropriate disposal of manure and dead poultry.

16. Fowl pox
 Fowl pox (FP) is a viral disease in hens, turkeys and many other birds
 It is a relatively slow-spreading viral infection
 It occurs in both a wet and dry form. The wet form is characterised by
plaques in the mouth and upper respiratory tract.
 The dry form is characterised by wart-like skin lesions that progress to thick
scabs.
 The disease may occur in any age of bird, at any time. Mortality is usually not
significant unless the respiratory involvement is severe.
 Fowl pox can cause depression, reduced appetite and poor growth or egg
production. The course of the disease in the individual bird takes three to five
weeks.

17. Etieology
 Fowl pox is caused by an avian DNA pox virus
 Infection occurs through skin abrasions or bites, through the respiratory route
and possibly through ingestion of infective scabs. It can be transmitted by
birds, mosquitoes or fomites (inanimate objects such as equipment).
 A flock may be affected for several months as fowl pox spreads slowly.
 Recovered birds do not remain carriers.

18. Prevention
 There is no treatment for fowl pox and prevention is through vaccination of
replacement birds.
 As mosquitoes are known reservoirs, mosquito control procedures may be of
some benefit in limiting spread in poultry confined in houses.

19. Infectious coryza
 Infections Coryza is usually acute and sometimes chronic, highly infectious
disease of chickens
 Coryza is characterised by catarrhal inflammation of the upper respiratory
tract, especially nasal and sinus mucosae. Facial swelling , nasal discharge
and conjunctivitis are the main clinical symptoms.
 Infectious Coryza is caused by the
bacterium Avibacterium paragallinarum and is seen in many countries
especially in multi-age farms that are never depopulated.
 Morbidity is high but mortality low if uncomplicated, although it may be up to
20%.

20. Transmission
 The route of infection is conjunctival or nasal with an incubation period of 1-3
days followed by rapid onset of the disease over a 2-3 day period with the
whole flock affected within 10 days.
 This results in increased culling.
 Carriers are important with transmission via exudates and by direct contact.
It is not egg-transmitted.

21. Signs
 Facial swelling.
 Purulent ocular and nasal discharge.
 Swollen wattles.
 Sneezing.
 Dyspnoea.
 Loss in condition.
 Drop in egg production of 10-40%.
 Inappetance.

22. Treatment
 Antibiotic treatment will reduce the severity of the course of the disease.
This contributes to a reduction of egg production losses. Be aware that
antibiotics do not eliminate the bacteria, birds remain carriers of the
bacterium.
 vaccines are used to prevent infection in high incidence areas. However,
control of the disease requires good husbandry practices. Prevention is best
achieved using biosecurity principles based on an all-in/all-out replacement
policy and ensuring replacement birds are not infected. If infection occurs,
complete depopulation followed by thorough cleaning/disinfecting is the only
means for eliminating the disease. The bacterium survives 2-3 days outside
the bird but is easily killed by heat, drying and disinfectants.

23. Fowl Cholera
 Fowl cholera is a contagious bacterial infection. The disease can range from
acute septicemia (blood poisoning) to chronic and localised infections
 disease caused by the bacterium Pasteurella multocida
 morbidity and mortality may be up to 100%.

24. Transmission
 The route of infection is oral or nasal with transmission via nasal exudate,
faeces, contaminated soil, equipment, and people.
 The incubation period is usually 5-8 days.
 Predisposing factors include high density and concurrent infections such as
respiratory viruses.

25. Signs
 Clinical findings vary greatly depending on the course of the disease.
 In acute cases, increased mortality is usually the first indication.
 Affected birds have swelling of the face or wattles, discharge from the
nostrils, mouth and eyes which may become “cheesy”, laboured breathing
and, in some cases, lack of coordination.
 The face, combs and wattles may become cyanotic (turn a bluish colour).
 Other symptoms include depression, loss of appetite, lameness, diarrhea and
ruffled feathers.

26. Prevention
 Fowl cholera can be treated with sulfonamides and antibiotics. Vaccines are
available but give variable results
 The disease is best controlled by eradication
 Prevention relies on good biosecurity practices, with good sanitation and
rodent control and separation of birds by age with thorough cleanout between
flocks.
 This bacterium is susceptible to ordinary disinfectants, sunlight, drying, and
heat.

27. Avian Salmonellosis
 Pullorum disease is an infectious poultry disease caused by the
bacterium Salmonella pullorum. The disease affects mainly young chicks and
poults, but can also affect older chickens, game birds, guinea fowl, ostriches,
parrots, peafowl, ring doves, sparrows and turkeys.
 Fowl typhoid is an infectious poultry disease caused by the
bacterium Salmonella gallinarum. The disease affects mainly mature or
growing chickens, but has the ability to affect all chickens, ducks, grouse,
guinea-fowl, peafowl, pheasants, quail and turkeys.

28. Signs
The clinical signs of pullorum disease and fowl typhoid are very similar. Pullorum
disease is generally a disease of young chicks and poults, while fowl typhoid is
more predominant in growing and adult birds.
 In young birds:
 anorexia;
 depression;
 diarrhea;
 dying or death (highest mortality rate in the first 2 weeks of life and in
incubators); and
 laboured breathing.

29. Signs
In growing and mature birds:
 anorexia;
 decreased egg production;
 depression;
 diarrhea;
 high fever;
 increased mortality (usually higher in chickens than turkeys); and
 poor hatchability.

30. Transmission
 The most common ways for these diseases to spread is through contact with
infected birds, and the transmission from hens to chicks through the egg.
Game birds and backyard flocks may act as reservoirs for the infection.
 These diseases can also spread via contaminated feed, water and litter, as
well as through contaminated clothing, footwear, vehicles and equipment.

31. Treatment
There are no treatments available for these diseases, but the best ways to
protect flocks from these diseases are through the following:
 keep poultry away from areas frequented by wild fowl;
 keep strict control over access to poultry houses;
 keep equipment cleaned and disinfected before taking it into poultry houses;
 do not keep bird feeders or create duck ponds close to poultry barns as they
attract wild birds; and
 maintain high sanitation standards.