Colibacillosis is caused by infection with a pathogenic strain of Escherichia coli. Signs vary and can include acute fatal septicemia, airsacculitis, pericarditis, perihepatitis, and lymphocytic depletion of the bursa and thymus. Diagnosis is made by isolation of a pure culture of E coli. Most bacterial isolates are resistant to multiple antibiotics, so prevention of exposure through good management is recommended.
Duck viral hepatitis is an acute infectious disease affecting young ducklings. It is associated with high mortality and characteristic liver lesions. Diagnosis is by viral isolation or PCR. Vaccination and biosecurity controls can be used for prevention, as there is no specific treatment for infected ducks. Enterococcosis has been reported in a variety of avian species worldwide.
Enterococcus spp are normal microflora found in the intestinal tract of poultry and other bird species. Enterococcus infections usually occur secondary to another disease. However, in recent years, Enterococcus cecorum has become an emerging pathogen in poultry, especially broilers. These pathologic changes have resulted in increased mortality, poor production, and increased condemnation. Diagnosis is confirmed by isolation of the organism.
Erysipelas is an infection caused by Erysipelothrix rhusiopathiae. Common clinical signs are sudden death, cutaneous lesions, and swollen hocks. Treatment is generally with rapid-acting penicillin. Erysipelas is zoonotic.
Fatty liver hemorrhagic syndrome is a metabolic disorder of chickens. The presenting complaint is typically sudden death of birds fed high-energy diets with limited exercise.
Diagnosis is based on finding liver hemorrhage and fat engorgement at necropsy. The disorder can be controlled by monitoring feed intake and body weight when birds are in a positive energy balance. Changing the balance of carbohydrates and fat in the diet and supplementing with selenium may also help. Sudden death syndrome occurs in rapidly growing young broiler chickens.
The etiology is uncertain, but it may be a metabolic disorder that predisposes birds to cardiac arrhythmia. Affected birds die suddenly and have no specific gross lesions. The diagnosis is based on the clinical presentation, lack of gross lesions, and supported by characteristic microscopic cardiac lesions.
Reducing the growth rate, particularly during the first 3 weeks of life, can reduce the incidence. Fowl cholera is a contagious, bacterial disease of birds caused by Pasteurella multocida. Acutely, it causes elevated mortality. Chronically, it causes lameness, swollen wattles in chickens , pneumonia in turkeys , and torticollis, but it can also be asymptomatic.
Both attenuated live vaccines and adjuvanted bacterins are available to aid in prevention, and it is sensitive to some antibiotics. Fowlpox is a worldwide viral infection of chickens and turkeys. Nodular lesions on unfeathered skin are common in the cutaneous form. In the diphtheritic form, which affects the upper GI and respiratory tracts, lesions occur from the mouth to the esophagus and on the trachea.
Diagnosis is by observing characteristic gross and microscopic lesions and PCR. Vaccination can prevent the disease and limit spread in affected flocks. Helminthiasis is infection by members of the phylum Nematoda roundworms or the class Cestoda tapeworms, flatworms. In rare cases, infected birds develop clinical signs such as apathy or diarrhea, and the influence on zootechnical parameters is usually negligible. Infections are diagnosed by the presence of worms in affected organs, mostly the intestines, or by detection of eggs in the feces.
Increasingly fewer compounds are available for treatment of chickens and other food-producing poultry, and control relies on improvement of management and sanitation. The hemorrhagic enteritis virus belongs to the family Adenoviridae , genus Siadenovirus , species turkey adenovirus 3 TAdV3 , and it is serologically indistinct from the marble spleen disease virus.
Clinical signs include splenomegaly in both turkeys and chickens, bloody diarrhea in turkeys, and acute respiratory disease in chickens. Clinical signs and lesions may allow a provisional diagnosis, which is normally confirmed by molecular diagnostic tests.
There is no direct treatment available, but live vaccines can be used for prevention and to control outbreaks.
Hygiene measures should be implemented to reduce the risk of secondary infection as a consequence of virus-induced immunosuppression. The protozoan Histomonas meleagridis infects a wide range of gallinaceous birds and causes histomoniasis blackhead disease. Clinical signs include drooping head and wings, prolonged standing, closed eyes, ruffled feathers, emaciation, and sulfur-colored droppings.
Diagnosis is based on pathognomonic ulceration of the ceca and necrotic lesions in the liver. There are no approved treatments or vaccines. Signs can include depression, watery diarrhea, ruffled feathers, and dehydration. Macroscopic and microscopic lesions in the cloacal bursa and molecular identification of the viral genome are used to diagnosis the disease. Vaccination to induce maternal immunity in young chicks is initially used to control the disease.
Vectored and live-attenuated vaccines can be used to induce active immunity in chicks as the maternal antibodies wane.
Listeriosis affects a wide range of bird species, but most infections do not cause clinical signs. Sporadic cases in backyard chickens may cause encephalitis or septicemia and sudden death. Diagnosis is confirmed by histochemical staining that identifies Listeria monocytogenes, the causative organism, in affected tissues. Several antibiotics can be effective treatment for the septicemic form of the disease.
Prevention should focus on eliminating potential sources of infection. There is a significant risk of zoonotic transmission. Malabsorption syndrome is characterized by stunted growth and lack of pigmentation in growing chickens. A viral cause is suspected but has not been confirmed. There are no confirmatory tests or effective treatments. Mycoplasmas are bacteria that lack a cell wall, are small in size, and have the smallest genome among all independently replicating forms of life.
Because of their small genome and the lack of many metabolic pathways, they are fastidious microorganisms. For isolation, they have complex nutritional requirements but will grow on specialized artificial medium containing serum. Growth in broth and on agar media is slow 5—21 days , and the small 0. Mycoplasmas do not survive for more than a few days outside the host and are vulnerable to common disinfectants.
Hundreds of mycotoxins affect poultry, with varying degrees of pathogenicity. They can have additive effects with other toxins, infectious agents, or nutritional deficiencies. Diagnosis requires detection and quantification of the specific toxin. Treatment includes removal of contaminated feed and supportive care. Prevention includes management practices that avoid mold growth during feed preparation, transport, and storage.
Depending on whether the etiologic agent is known, neoplasms of poultry are divided into two main categories: virus-induced neoplasms and neoplasms of unknown etiology. Although these neoplastic diseases cause economic losses from tumor mortality and poor performance, some of them have served as highly suitable models to study neoplasia. Newcastle disease is an infection of domestic poultry and other bird species with virulent Newcastle disease virus NDV.
It is a worldwide problem that presents primarily as an acute respiratory disease, but depression, nervous manifestations, or diarrhea may be the predominant clinical form.
Severity depends on the virulence of the infecting virus and host susceptibility. Occurrence of the disease is reportable and may result in trade restrictions. It is more likely in unclean environments, which allow opportunistic bacterial infection. Signs include navel inflammation, anorexia, depression, reduced weight gain, and increased mortality in the first 2 weeks after hatching.
Treatment of affected birds with antibiotics is often ineffective. Prevention is by improving sanitation and general husbandry. Riemerella anatipestifer is a bacterial pathogen that affects ducklings, gosling, turkeys, and other fowl. Clinical signs include ocular and nasal discharge, mild coughing and sneezing, watery green feces, and neurologic signs progressing to obtundation and death.
Diagnosis is based on typical neurologic signs, pathological lesions, and identification of the causative organism. Careful management practices are important for prevention. Salmonella infections are classified as nonmotile serotypes S enterica Pullorum and S enterica Gallinarum and the many motile paratyphoid Salmonella.
These Salmonella infections have a worldwide distribution. Historically, S enterica Arizonae was placed in its own category, but it is now included with the paratyphoid Salmonella. S enterica Arizonae is an egg-transmitted disease primarily of young turkeys.
In addition to the above nonmotile salmonellae, Salmonella paratyphoid infections in poultry are relatively common and have public health significance because of contaminated poultry product consumption. Several different normally present Staphylococcus spp can cause localized or systemic infection in poultry if skin or mucous membrane barriers are compromised. Clinical signs vary, depending on the location infected. Diagnosis is confirmed by culture of lesions.
Antibiotic treatment of systemic infection is often successful, but localized lesions can be more difficult to treat. Streptococcosis is caused by bacteria that are part of the normal flora of the intestinal tract, so infections are often thought to occur secondarily to other diseases.
It has been reported in numerous bird species throughout the world. There are two forms of the disease, an acute septicemic form and a chronic form. Diagnosis is confirmed with isolation of the organism via culture. Treatment has been effective for early acute infections, with efficacy decreasing as the disease becomes chronic. Tuberculosis, caused by Mycobacterium avium , can affect all birds, although susceptibility varies by species. Infection is chronic, leading to emaciation, decreased egg production, granulomas in multiple tissues, and death.
Diagnosis is best made through necropsy demonstration of the bacteria in tissue samples. Because of the risk of creating drug-resistant strains, treatment is not recommended. Contaminated premises should not be used to raise poultry.
Although M avium can infect humans, serovars found in birds and people are typically different. Nonetheless, precautions to avoid human exposure should be taken with infected birds. Turkey viral hepatitis TVH is a disease of young turkeys characterized by the presence of hepatitis with or without pancreatitis. The virus is shed in droppings and transmitted by both direct and indirect contact. No specific treatments or preventive measures are available. Ascites is an accumulation of noninflammatory transudate in one or more of the peritoneal cavities or potential spaces.
The fluid, which accumulates most frequently in the two ventral hepatic, peritoneal, or pericardial spaces, may contain yellow protein clots. Ascites may result from increased vascular hydraulic pressure, vascular damage, increased tissue oncotic pressure, or decreased vascular oncotic usually colloidal pressure, but is most commonly associated with venous hypertension resulting from right heart failure in response to increased pulmonary resistance. Cimex lectularius bedbug is a common bloodsucking parasite of people, but it can also feed on many other warm-blooded animals, including poultry.
Bedbugs spend most of their time off the host in cracks and crevices, traveling to the host to feed at night. Because of this life history, it is rare in modern caged-laying operations. Bedbugs require a more complex environment eg, nestboxes and may become problematic in furnished-cage or cage-free layer facilities, breeding houses, pigeon lofts, etc.
Gangrenous dermatitis is a disease of turkeys and chickens caused by Clostridium septicum , C perfringens type A, and Staphylococcus aureus , either singly or in combination. The condition is characterized by rapid onset of acute mortality. Birds succumbing to the infection have necrosis of the skin and subcutaneous tissue, usually involving the breast, abdomen, wing, or thigh.
Production characteristics of modern poultry lines eg, body weight in broiler chickens, egg production in laying hens place high demands on the skeletal system, and inadequacies in nutrition or husbandry often result in skeletal diseases.
Skeletal disorders may be primarily infectious or noninfectious; both may be seen concurrently within a flock. Skeletal disorders cause lameness from biomechanical dysfunction and in broiler chickens result in poor growth, culled birds, increased mortality caused by starvation and dehydration , and carcass condemnation and downgrading. Bone fractures in spent hens may be a welfare issue. Exertional myopathy results from overly strenuous muscular exercise and can be precipitated by preexisting conditions such as selenium deficiency.
In cases that present clinically, birds appear lame and may have ruptured tendons. There are no treatment options, other than general supportive care, for birds once clinically affected. Prevention of clinical signs relies on the generation of a protective, serotype-specific immune response. Enteric viruses of poultry are common and pervasive.
They are potentially as diverse as enteric bacteria and are responsible for production diseases resulting in substantial financial losses. Many of these viruses have RNA genomes that continually evolve, leading to multiple circulating strains of varying pathogenicity.
They can be difficult to diagnose due to confounding issues, such as their presence in healthy birds, variable pathogenicity, age-related resistance, coinfection with other pathogens, and lack of convenient diagnostic tests.
They are associated with complex syndromes, such as malabsorption syndrome of broiler chickens and poult enteritis mortality syndrome, but also of diseases outside the enteric system, such as tenosynovitis caused by avian orthoreovirus. Recent metagenomics studies are beginning to shed light on the causes of some complex production diseases, and some of the more prominent virus families are described in this chapter, including astroviruses, coronaviruses, parvoviruses, picornaviruses and rotaviruses.
Avian encephalomyelitis is a viral infection affecting the CNS of several species of birds. Signs include tremors, ataxia, and weakness that progresses to paralysis. Diagnosis is based on history, clinical signs, histopathology, and isolation of the virus. A live vaccine is available to prevent transmission and reduce egg losses. Botulism is a toxic disorder resulting from ingestion of the exotoxin produced by Clostridium botulinum.
It affects a wide variety of birds and mammals. Some publications are available in both digital and print versions, but some are only available in one version. Please refer to the publication description to learn whether or not a specific publication is available in digital, print, or both.
Send Answer All answers will be displayed after moderation. What happens after I purchase a digital publication? If I purchase a digital publication, will I be able to download updated versions or replacement copies in the future? If a new edition is released, you will need to purchase the new version to have access to the new version.
Can I share a digital or publication with multiple people? We are sorry, but digital publications cannot be shared with multiple people. How much is shipping on print publications? Shipping is dependent on the weight of the publication as well as the quantity ordered. You will receive an accurate quote for shipping during checkout and prior to completing your purchase. When will my print publication arrive? You will receive a delivery date estimate after you check out, and a tracking link when your order has shipped.
A publication I want to purchase is out of stock. What should I do? You can sign up for an out of stock alert on the publication page and we will send you an email notification when the publication is back in stock. Are publications accessible for people who require special needs or services? Yes, our publications are available in alternative formats upon request. We will be glad to assist you. Who do I contact if I have a question about a specific publication? Poultry Fly Management Sections 11 Length 10 hours.
Micoplasmosis Aviar By Gino Lorenzoni. Coccidiosis Aviar By Gino Lorenzoni.
0コメント