Common diseases in backyard poultry in Great Britain (excluding gamebirds) - Part 1

 On this week's post, we will refrain from sharing pictures due t the sensitivity of the matter. However, we still feel it is important to share so people know when their birds are needing veterinary care and when to isolate them. 

With this in mind, let's start. 

Neoplasms

Neoplasms are, by far, the most common diagnosis in backyard chickens. 

Neoplasms fall into two categories, those with an infectious aetiology such as Marek’s Disease, and those with a non-infectious aetiology. The latter are usually sporadic and not of great economic significance, such as adenocarcinomas. 

Diagnosis is done by post-mortem examination (PME) and histopathology.

Marek's disease (MD)

This is a lymphoproliferative and neuropathic disease in chickens. It is less commonly present in turkeys. 

MD is caused by a cell-associated herpesvirus and can cause significant mortality and symptoms. Treatment is not possible. Vaccination is used in commercial flocks. 

Classical symptoms are:

• paralysis of legs or wings;
• paralysis of the neck (torticolis) with peripheral nerve enlargement.

Other symptoms may also be present:

• Multiple visceral tumours (multifocal lymphona)

Diagnosed by PME and histopathology. 

E-Coli infections and colisepticaemia

E-Coli infections can lead to a variety of diseases, including colisepticaemia. When affecting multiple body systems, could develop polyserositis.

In chicks, during the first week of life, E-coli may cause yolk sac infection (omphalitis or mushy chick disease), characterised by abnormal discoloration of the yolk sac contents, usually non-absorbed and with a malodorous smell. Airsacculitis due to E. Coli is often secondary to viral, mycoplasmal or environmental challenge (dust and/or ammonia). 

E. Coli is also associated with egg peritonitis, including egg yolk coelo

Diagnosis requires PME. 

Respiratory disease

This is one of the most common presentations in backyard poultry. They are often multifactorial and may be caused by noninfectious factors (dust, ammonia) and/or infectious causes. 

The latter includes viral, bacterial, mycoplasmal and fungus: avian influenza, Newcastle disease, infectious laryngotracheitis virus (ILT), infectious bronchitis virus (IBV), pasteurella multocida (Fowl Cholera), Mycoplasma gallisepticum, Avibacterium paragallinarum (Infectious Coryza) and Aspergillosis. 

Respiratory aspergillosis (brooder pneumonia) is a commonn mismanagement problem, with exposure by inhalation os environmental spores. Newly hatched turkeys, chickens and ducks are highly susceptible. Co-infections with respiratory pathogens can occur quite often. The severity of the disease can also be influenced by the environmental and host factors, complicating the diagnosis. 

Primary viral (mycoplasma) associated respiratory disease may predispose to secondary bacterial infection, although bacterial pathogens can cause disease in their own right. Laboratory testing and veterinary care are essential to reach an accurate diagnosis in order to provide appropriate advice on prevention and treatment. Flock serology can be used to demonstrate exposure (in particular for Mycoplasmosis).

Mycoplasmosis (Mycoplasma gallisepticum)

It cam cause acute or chronic respiratory disease but often presents as a persistent or recurrent respiratory disease in backyard flocks. 

Diagnosis by serology and PCR/DGGE (http://www.defra.gov.uk/ahvla-en/diseasecontrol/non-notifiable/mycoplasmosis/#avian Infectious).

 Coryza

This is typically and acute and highly contagious bacterial disease of the upper respiratory tract. It presents clinically as severe nasal discharge, sinusitis and facial oedema. A drop in egg production may also be noticed. 

Diagnosis required PME and bacteriology (http://www.defra.gov.uk/ahvla-en/diseasecontrol/non-notifiable/infectious-coryza)

Viral diseases infectious bronchitis

This is an acute and highly contagious viral respiratory disease with high morbidityand typically low mortality. It can be accompanied by a sharp drop in egg production and affects egg quality. 

Neurological signs are not a feature of this condition. 

In broilers, IB has been associated with renal damage, mortality and poor performance. 

IB vaccination is common in commercial flocks. For detection of IBV and IBV-like gammacoronaviruses, there is real-time RT-PCR and other molecular tests.

Infectious Laryngotracheitis (ILT) 

This is an acute viral disease of chickens which presents as severe dyspnoea (gasping) with bloody mucus and high mortality in adult birds. Introduction of te infection is usually by asymptomatic carriers. 

Diagnosis is carried out by PME and histopathology. Vaccination is available for prevention. 

Hope you have fund this post helpful. Next week, we will continue on the same subject. 

Until then, 

With love, from our team, 

FL Poultry