Yersiniosis - Birds

Also known as: Avian Pseudotuberculosis

Caused by: Yersinia pseudotuberculosis

Introduction

The causal organism is Yersinia pseudotuberculosis, a Gram-negative coccobacillus. There are variations in virulence, and its survival outside the body is similar to Pasteurella multocida.

The disease has a worldwide distribution, affecting the various species of domestic poultry and a wide variety of wild and caged birds and rodents.

Clinical cases in commercial poultry are uncommon and usually result from faecal contamination of the birds' environment or feed.

It has been reported in humans but is not an important zoonosis. Human infection is usually linked to the consumption of food contaminated by birds or rodents.

Young birds between 4-10 weeks are more susceptible.

The bacteria gain entry through the intestinal mucosa or occasionally through breaks in the skin. Y. pseudotuberculosis can be a normal gut inhabitant of a variety of migratory avian species and this may be relevant to the introduction of pseudotuberculosis into a region.

Clinical Signs

Signs are not very specific.

Chronic cases show persistent diarrhoea, weakness, ruffled feathers, lameness and progressive emaciation.

Some birds may show no premonitory signs and may just be found dead.

Diagnosis

Post-mortem findings include: enlargement of the liver and spleen, mottled or speckled appearance of the affected organs.

Chronic cases may show multiple caseous tubercle-like lesions of varying size in the liver, the spleen and sometimes the lungs. Severe enteritis may be observed.

The organism can be isolated and identified from blood or lesions.

Histopathological confirmation on liver or spleen can be helpful.

Treatment and Control

Treatment may be of benefit for at-risk birds within a flock in which disease has been diagnosed. Treatment can be administered via the drinking water, and antibiotics available include: sulfadiazine/trimethoprim or those from the tetracycline group. Further administration should be on the basis of culture and sensitivity testing.

Prevention depends on high standards of hygiene and management. Direct contact with wild birds and rodents should be prevented, and contamination of feed or the environment with faeces from these animals should be avoided.

Yersiniosis - Birds Learning Resources
Flashcards Test your knowledge using flashcard type questions	Avian Medicine Q&A 19

References

Chauhan, Y. (1996) Poultry Diseases, Diagnosis and Treatment New Age International

Pattison, M. (2008) Poultry Diseases Elsevier Health Sciences