GENERAL INTRODUCTION: PARAMYXOVIRIDAE AND PNEUMOVIRIDAE

PARAMYXOVIRIDAE AND PNEUMOVIRIDAE

A General Introduction has been added to each disease chapter in an attempt to give a brief updated overview of the taxonomic, biological and other characteristics of the virus family or group of bacteria /protozoa that cause disease in livestock and, where relevant, involve wildlife. As the text of the three-volume book Infectious Diseases of Livestock is currently under revision the Editors are aware that there are inconsistencies between the updated introductions to chapters and the content of the chapters themselves. Once the chapters have been updated – a process that is currently underway – these inconsistencies will be removed.

Paramyxoviridae and Pneumoviridae (formerly a subfamily within the Paramyxoviridae) are currently classified with 7 other familiesin the Order Mononegavirales.

The Paramyxoviridae consist currently of 54 viruses divided into 7 genera (Aquaparamyxovirus, Avulavirus, Ferlavirus, Henipavirus, Morbillivirus, Respirovirus & Rubulavirus).  Among these viruses are some of the most devastating infectious diseases of humans and livestock; measles in humans, canine distemper, rinderpest (cattle) and Newcastle disease (poultry) have arguably caused more death and destruction than any other group of animal viruses in recorded history. Pneumoviridae, a related family, on the other hand, consists of only two genera (Metapneumovirus & Orthopneumovirus) that have little impact on livestock. An exception is bovine respiratory syncytial virus, now classified as Bovine orthopneumovirus within the Genus Orthopneumovirus.  

Paramyxoviruses occur only in vertebrates and all are transmitted directly between infected and susceptible hosts, i.e., none are dependent on vectors for transmission. This is one of the factors that enabled the global eradication of the rinderpest – the first animal disease officially to be recognised as such in 2011. The related high-impact disease of goats and sheep, peste des petits ruminants, has now similarly been targeted for global eradication using the same approach.

Viruses associated with a variety of wildlife species are classified as paramyxoviruses and it is likely that more will be uncovered in the near future. These include viruses associated with bats, i.e. members on the genera Henipavirus (e.g. Hendra- and Nipahviruses) and Rubulavirus (e.g. Menangle and Tioman viruses). These have crossed species barriers into horses, pigs and humans with high fatality rates among the latter, thereby resulting in considerable alarm.  

Paramyxoviruses and pneumoviruses have relatively large (150-300 nm in diameter) pleomorphic virions that are usually roughly spherical in shape but can also be filamentous. They are surrounded by an envelope derived from the host-cell membrane from which prominent glycoprotein “spikes” project that enable attachment to and fusion with host cells.  The genomes of these viruses consist of linear, single-stranded, negative sense RNA that encodes 6 to 10 open reading frames1.

Table 1 Infections of mammalian livestock caused by viruses within the Paramyxoviridae and Pneumoviridae families

Family

Genus

Species (former names)

Virus common name

Livestock species affected (source of infection)

Disease

Comments

Paramyxoviridae

Henipavirus

Hendra henipavirus

Hendra virus

Horses (fruit bats)

Interstitial pneumonia accompanied by pulmonary oedema

Increasing discovery of related viruses hosted by fruit bats that are able to cross species barriers – the ancestral viruses were possibly associated with African fruit bats

Nipah henipavirus

Nipah virus

Pigs (fruit bats)

Febrile respiratory illness with epistaxis, dyspnoea and coughing in young pigs

Others including Ghanaian bat henipavirus

 

?

?

Morbillivirus

Rinderpest morbillivirus

Rinderpest virus

Cattle – some wild bovids may serve as temporary hosts

Rinderpest

Officially declared as eradicated (2011)

Small ruminant morbillivirus

Peste des petits ruminants virus

Goats, sheep and possibly some wild ungulates

Peste des petits ruminants

 

Respirovirus

Bovine repirovirus 3

Bovine parainfluenza 3 virus

Cattle and possibly some other ruminants

Bovine respiratory disease

Involved in the bovine respiratory disease complex

Porcine respirovirus 1

None

Pigs

Possible association with porcine respiratory disease

Newly identified virus

 

Rubulavirus

Porcine rubulavirus

La-Piedad-Michoacan-Mexico virus

Pigs (fruit bats?)

Neurological disease, conjunctivitis with corneal opacity and mortality

These and other viruses associated with fruit bats possibly affect pigs and other species via ‘spill-over’ from sylvatic cycles of infection

Mapuera rubulavirus

Mapuersa virus

Virus associated with fruit bats

Unknown – possibly similar to porcine rubulavirus

Menangle rubulavirus

Menangle virus

Pigs

Associated with SMEDI-type reproductive failure in pigs

Tioman rubulavirus

Timoan virus

Virus isolated from fruit bats

Mild disease in pigs following experimental infection

Pneumoviridae

Orthopneumovirus

Bovine orthopneumovirus

Bovine respiratory syncytial virus

Cattle

Bovine respiratory disease (part of the bovine respiratory disease complex)

 

Metapneumovirus

Unclassified

Salem virus

Horses

Febrile illness accompanied by oedema of the legs

 

References

  1. International Committee for Taxonomy of Viruses https://talk.ictvonline.org/taxonomy/ (accession date: 26/05/2017)
  2. MACLACHLAN N.J. & DUBOVI, E.J. (eds.), 2016. Veterinary Virology, 5th edition, Academic Press.