Inclusion Body Rhinitis
Also Known As – Inclusion Body Rhinitis – Atrophic Rhinitis – IBR – Cytomegalic Inclusion Disease
Caused By – Suid Herpesvirus 2 – SHV-2 – Inclusion Body Rhinitis Virus – Pig Cytomegalovirus – IBRV - PCMV
Introduction
Porcine Cytomegalovirus is a herpesvirus causing Inclusion Body Rhinitis in pigs.
PCMV may pose a risk to humans through transplanted organs and this is currently being researched. It is not currently considered a zoonosis due to its host range being highly restricted ot only the pig.
This disease is notifiable to the World Organisation for Animal Health (OIE)
Distribution
Global. No country has established freedom from or eradication of disease.
Prevalence of infected herds and infected pigs within a herd is very high albeit with a low incidence of clinical disease.
PCMV can cross the placenta facilitating vertical transmission. Horizontal transmission between infected pigs is also important.
Signalment
Clinical signs are largely restricted to piglets under 3 weeks of age. They can be infected in utero or as neonates.
Clinical Signs
Rhinitis – Snuffling, sneezing, coughing, production of purulent/catarrhal discharge, increased lacrimation, conjunctivititis, ocular discharge, epistaxis, dyspnoea.
Anorexia, anaemia, lethargy, pyrexia and sudden death.
Pneumonia may occur.
Reproductive failure caused by PCMV is characterised by abortion, mummified piglets and birth of stillborn, weak or stunted pigs. Ulcers and erosions may form on the external genitalia. Sows may develop agalactia.
Gastrointestinal and neurological signs can also develop.
In common with all herpesviruses, PCMV can become latent and recrudesce with stress.
Diagnosis
Diagnosis is often based by the observation of mummified or weak litters along with signs of rhinitis and respiratory disease on a unit.
Black discolouration around the eyes due to conjunctival exudate is also suggestive.
Antigen can be detected serologically by Fluorescent Antibody Test (FAT). Antibody can be detected by Indirect Fluorescent Antibody Test (IFAT).
PCR tests for PCMV have now also been developed and are very sensitive.
On post-mortem, petechiation of the heart, kidneys, intestine, lungs, lymph nodes and meninges is seen in neonatal and foetal pigs. Pulmonary congestion is marked and the bronchial and mediastinal lymph nodes are dramatically enlarged. Ventral aspects of lung lobes are often discoloured purple. The nasal mucosa is congested with a mucoid exudates.
Histologically, large basophilic intranuclear inclusion bodies are present in the mucosal epithelial cells of the turbinates, salivary glands and kidney tissues. Electron microscopy can also be used for the same purpose.
Treatment
Natural outbreaks often resolve without intervention.
Control
No vaccine has been developed for PCMV.
Reducing stress especially when new stock is introduced and minimising the mixing of litters may reduce severity and frequency.
No national control schemes are in place.
| Inclusion Body Rhinitis Learning Resources | |
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Porcine Cytomegalovirus Flashcards |
References
Animal Health & Production Compendium, Inclusion Body Rhinitis datasheet, accessed 16/06/2011 @ http://www.cabi.org/ahpc/