Avian - mareks, myoplasma, and turkey bordatella
MG signs broiler chickens
"Chronic respiratory disease" with coughing, sneezing (snicks), oculonasal discharge, poor feed conversion and air sac condemnations at processing.
MG signs turkey
"Infectious sinusitis"; swelling of one or both infraorbital sinuses, with nasal exudate on wings and air sac condemnations at processing.
Mycoplasma Gallisepticum (MG) Infection
A chronic disease of a variety of birds, especially chickens and turkeys, characterized by nasal exudate, coughing and debilitation. It has been a major problem in the poultry industry for over 60 years. Commercial breeder flocks are monitored for MG by the National Poultry Improvement Plan (NPIP).
Turkey Bordetellosis (Bordetella avium)
Acute, persistent upper respiratory infection of turkeys with conjunctivitis, ocular exudate, rhinitis and tracheitis.
Mycoplasma Gallisepticum clinical signs
Adult laying hens: signs are rare, but include decreased egg production; decreased feed consumption and increased medication costs.
Turkey Bordetellosis causes
Bordetella avium; infection can be exacerbated by Newcastle Disease virus, Mycoplasma gallisepticum, Pasteurella, or E. coli, to increase the severity of the turkey coryza.
Marek's Disease (MD)
Marek's disease is a herpesvirus infection, primarily of young chickens, that causes lymphoma of T lymphocytes. Tumors may occur in the nerves, ovaries, testes, viscera, eye, muscle, and skin. MD is ubiquitous throughout the world. The leg paralysis was often referred to as range paralysis.
Turkey Bordetellosis clinical signs
Nearly 100% of birds affected have a low mortality, especially with uncomplicated infections. Higher mortality occurs if the disease is complicated by E. coli or Pasteurella infection. Symptoms include: ● Voice change: loss of voice ● Snicking, flicking of head ● Mucus around nostril, dirty shoulders from rubbing head on feathers ● Huddling, depressed, decreased feed consumption, decreased weight gain ● Swollen sinuses, submandibular swelling ● Conjunctivitis: foamy fluid underneath eyelids ● Dyspnea: difficulty breathing
Marek's Disease (MD) latent infection
Occurs in lymphocytes, predominantly T cells, but occasionally B cells. Theviral genome is not expressed and no virus or tumor-associated antigen is produced.
Marek's Disease (MD) transforming infection
Occurs in only T lymphocytes and is caused by only the virulentserotype 1 Marek's disease viruses. This transformation in T lymphocytes results in theformation of neoplastic lymphocytes with viral antigen expressed. MD tumor-associated antigen is expressed on the cell surface.
Marek's Disease (MD) productive infection
Occurs mainly in nonlymphocytic cells with replication of viral DNA, antigen synthesized and viral particles are sometimes produced. Full productive infection occurs in feather follicle epithelium that develops large numbers of enveloped and fully infectious viruses.
Mycoplasma Gallisepticum gross lesions - turkey
Swollen sinuses containing clear, serous fluid, usually MG alone
Mycoplasma Gallisepticum gross lesions - chicken
Uncomplicated MG - mild catarrhal sinusitis, tracheitis, and airsacculitis
Mycoplasma Gallisepticum treatment
Usually does not eliminate infection and does not prevent egg transmission of infection. Treatment with tylosin can reduce the clinical signs, but will not eliminate the infection.
Marek's Disease (MD) replication
replication occurs in three phases of virus-cell interactions: Productive, latent and transformation.
Turkey Bordetellosis gross lesions
● Mucus within sinuses ● Tracheal collapse ● Submandibular edema ● Exudate around eyes (raccoon eye) ● and on wing feathers ● If secondary E. coli infection is present, pericarditis, perihepatitis and airsacculitis will be observed.
Turkey Bordetellosis diagnosis
Gross lesions, necropsy, histopathology, bacterial culture
Mycoplasma Gallisepticum synonyms
● "Chronic respiratory disease" of chickens ● "Infectious sinusitis" of turkeys ● MG ● CRD
Mycoplasma Gallisepticum epidemiology
● "Chronic respiratory disease" of chickens is usually complicated by Escherichia coli infection, Newcastle disease virus or infectious bronchitis virus. ● MG alone produces mild lesions in chickens. MG can be a common inhabitant of the upper respiratory tract of clinically healthy birds.
Marek's Disease (MD) diagnosis
● A presumptive diagnosis is made based on the presence of tumors andthe observed paralysis; however, gross necropsy and histopathology are important to make a definitive diagnosis and to differentiate Marek's disease from other forms of paralysis. ● PCR for MD viral nucleic acid can be conducted on peripheral blood white cell buffy coats or lymphoid tumors as confirmation; this is not readily available for backyard chickens because of expense and lack of laboratory testing.
Turkey Bordetellosis prevention
● All-in, all-out management is essential. The microorganism can be transmitted in contaminated water lines, so it is important to flush water lines between flocks. ● Never backtrack from older to younger turkeys on the farm. ● A killed injectable bacterin is available for breeder hens, and a live attenuated bacterin is administered (via drinking water) to turkey poults.
Marek's Disease (MD) gross lesions
● Birds can have one or both neural and visceral lesions. ● Affected nerves (sciatic, brachial and pelvic plexus) are characterized by swelling, loss of cross-striations, and are gray or yellow. ● Lymphoid tumors may be found in the gonads, ● heart, liver, lung, kidney, spleen, bursa, intestines, muscle, and skin.
Marek's Disease (MD) clinical signs
● Clinical signs and gross lesions generally do not appear until 4 weeks of age or later. ● In acute outbreaks, birds become severely depressed and uncoordinated followed by unilateral or bilateral paralysis of legs and wings. ● Many birds become dehydrated, emaciated, and eventually die. ● The extremities affected include the legs, wings, and neck. ● In an infected flock, mortality gradually builds and generally persists for 4-10 weeks. ● Ocular Marek's disease is characterized by decreased pupil size and irregular diameter ("grey eye"). ● Immunosuppression can be a long-term effect.
Mycoplasma Gallisepticum diganosis
● History, gross necropsy, histopathology, serum plate agglutination test, culture or polymerase chain reaction (trachea or sinus exudate). ● PCR has become the diagnostic test of choice and is available at a number of veterinary diagnostic labs.
Marek's Disease (MD) transmission
● Infectious virus is produced only in feather follicle epithelium and spreads by direct or indirect contact between birds. ● The infectious virus contaminates the premises through infected molted feathers and dander. ● Birds become infected when they inhale dust containing the virus. Many apparently normal birds are carriers that can transmit the infection. ● Some birds have been found to shed the virus from skin for as long as eighteen months.
Mycoplasma Gallisepticum cause
● Mycoplasma gallisepticum ● Mycoplasmas are small prokaryotes that lack a cell wall and are covered only by a plasma membrane. ● These organisms form round "fried-egg" colonies in culture and generally require a protein-rich medium that contains 10-15% animal serum. M. gallisepticum, M. synoviae and M. meleagridis have the ability to agglutinate turkey or chicken erythrocytes, a feature that is utilized in the hemagglutination-inhibition assay to detect antibodies to these agents.
Turkey Bordetellosis epidemiology
● Occurs most often in turkeys at 1-6 weeks of age, but all ages are susceptible. ● Farms with multi-age flocks and continuous confinement have the most problems with turkey coryza, especially in summer and fall. ● This agent has been occasionally associated with respiratory disease in broilers.
Turkey Bordetellosis transmission
● Spreads from bird to bird by contact with oculonasal secretions. ● Older flocks serve as recovered carriers and are the most important source of infection on multi-age farms. ● Infection can be carried between houses by human traffic. ● Litter and contaminated water can be sources of infection.
Marek's Disease (MD) cause
● The disease is caused by a cell-associated herpesvirus (double-stranded DNA virus, hexagonal enveloped virus 150-160 nm diameter). ● There are three serotypes of MD virus: The oncoviruses (tumor-causing) are serotype 1; non-oncogenic viruses are serotype 2; and the herpes virus turkey (HVT) is serotype 3. ● The virus is intranuclear (cell-associated) and normally cannot live outside the host cell being protected from the environment by host epithelium.
Marek's Disease (MD) treatment
● There is no effective treatment for chickens with Marek's disease. ● The emphasis is on prevention.
Mycoplasma Gallisepticum transmission
● Transovarian: transmitted from breeder birds to offspring through egg ● Horizontal infection via infected aerosols
Turkey Bordetellosis synonyms
● Turkey coryza ● Bordetella avium infection ● "Raccoon eye"
Marek's Disease (MD) prevention
● Vaccination against MD is effective in controlling the disease. ● Marek's disease vaccine is usually administered on day 1 or injected into the embryo three days prior to hatch (in ovo). ● There are three types of vaccines commercially available: the HVT serotype 3, natural occurring avirulent isolates of serotype 2, and non-oncogenic strains of serotype 1 (Rispens). ● MD vaccines often achieve over 90% protection under commercial conditions. At least 1000-1500 plaque-forming units of live virus are needed per dose. ● Chicks are normally vaccinated at the hatchery because they are exposed to the field virus at an early age. ● Cell-associated vaccines require extreme care in handling and application. ● Condemnations due to Marek's Disease can often be traced to errors in vaccination.
Mycoplasma Gallisepticum prevention
● Vaccination: administered to chickens only; vaccine can kill turkeys (F strain). ● A killed injectable (bacterin) or live spray vaccine is commercially available. ● Flock owners are encouraged to purchase chicks and poults from NPIP Mycoplasma certified-free breeder flocks.
