Also Known As: Turkey Rhinotracheitis Virus — Swollen Head Syndrome — APV — TRTV — TRV
TRV is not zoonotic.
The virus is widespread in Europe. It is known to be present in Asia, Africa, the Middle East, South America and North America too.
TRTV can replicate in the reproductive and respiratory systems. Its transmission is mainly oral.
Turkeys are generally more susceptible to the disease than chickens, and other domesticated species e.g. pheasants, guinea fowl, are affected. Intensive rearing systems with high stocking density are conducive to spread of the disease.
Clinical signs usually begin 3 days after infection but are mild initially. Mortality is highest in turkey poults and is usually due to secondary bacterial infection.
Respiratory disease is most common and causes tachypnoea, nasal discharge, dyspnoea, sneezing and abnormal breathing. Clinical disease is usually accompanied by a decrease in egg production and reproductive failure. Folded egg membranes and egg peritonitis may develop consequentially.
Torticollis, reluctance to move, swelling of the head, face and eyes and head shaking are manifestations of more severe cases.
Lack of growth and retardation will occur in young birds infected by TRV.
Viral isolation can be attempted from nasal turbinates, trachea or exudates, oesophagus and buccal cavity, and is most successful in turkeys.
Necropsy findings can also be suggestive:
- Clear to greyish exudate is present in the nasal turbinates and excess mucus is present in the trachea. Inflammatory exudates is evident microscopically.
- In hens, oviductal infection is represented by inspissated albumen forming white masses. Misshapen eggs may be present and ovarian regression evident.
- Other fowl
- Turbinate mucosae are discoloured red-purple by petechiation. The subcutaneous tissues covering the head are oedematous with fibrinopurulent inflammation. Pericarditis and perihepatitis are regularly seen.
- Egg peritonitis is also sometimes found.
There is no treatment for the viral infection but antibiotics administered in drinking water may minimise losses by treating secondary bacterial infection.
Vaccines are available against type A and B TRV for both turkeys and chickens, and are the main form of control in endemic countries. Killed vaccines must be first primed with a live vaccine to be effective.
Good biosecurity should always be practised including particular attention to storage and disposal of carcasses on the unit. Air quality should be monitored and maximised and birds of different ages segregated wherever possible.
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Gough, R.E. and Jones, R.C. (2008) Avian Metapneumovirus. In: Diseases of Poultry, 12th Edition (eds. Saif, Y.M., Fadly A.M., Glissen J.R., McDougald L.R., Nolan L.K., Swayne D.E.) Wiley-Blackwell, pp 100-110
Jones, R.C. (2007) Pneumovirinae. In: Poultry Diseases, 6th Edition (eds. Pattison, M., McMullin, P., Bradbury, J., Alexander, D.) Saunders, Elsevier, pp 294-316
The datasheet was accessed on 6 June 2011.
This article has been expert reviewed by Prof Dave Cavanagh BSc, PhD, DSc
Date reviewed: 23 August 2011
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