Introduction to Veterinary Virology – Key Vocabulary

A collection of key vocabulary terms, scientists, viruses, structural features, and stability factors from the lecture on veterinary virology.

Virology

The study of viruses and virus-caused diseases.

Virion

A complete virus particle consisting of nucleic acid surrounded by a capsid and, in some viruses, an envelope.

Capsid

Protein coat that encloses and protects the viral nucleic acid.

Envelope (viral)

Lipid-protein bilayer derived from host membranes that surrounds some virions.

Nucleic acid (viral)

Genetic material of a virus; can be RNA or DNA but never both.

Icosahedral symmetry

Capsid shape with 20 faces, 12 corners, and 30 edges.

Helical symmetry

Capsid structure in which protein subunits spiral around the nucleic acid; all animal helical viruses are enveloped.

Complex symmetry

Unique viral architecture found only in Poxviridae among vertebrate viruses.

Pasteur-Chamberland filter

Porcelain filter (1879) that retained bacteria, leading to the concept of viruses as "filterable agents."

Dmitri Ivanovski

Russian scientist who first described tobacco mosaic virus in 1892.

Martinus Beijerinck

Coined the term "contagium vivum fluidum" for tobacco mosaic virus.

Foot-and-mouth disease virus

First vertebrate virus discovered (1898) by Loeffler and Frosch.

Friedrich Loeffler

Co-discoverer of foot-and-mouth disease virus.

Paul Frosch

Co-discoverer of foot-and-mouth disease virus.

Rabies virus

Virus shown in 1903 to pass through bacteriological filters, confirming its viral nature.

Paul Remlinger

Demonstrated filterability of rabies virus (1903).

Hog cholera virus

First demonstrated in 1903 by de Schweinitz and Dorset using filtered pig blood.

Emil Alexander de Schweinitz

Helped prove viral cause of hog cholera.

Marion Dorset

Co-identified hog cholera virus with de Schweinitz.

African swine fever virus (ASFV)

Large enveloped DNA virus discovered in 1910; resilient to low temperature, inactivated by extreme pH.

R. Eustace Montgomery

Veterinarian who described African swine fever in East Africa (1910).

Newcastle disease virus (NDV)

Avian paramyxovirus first noted in 1926 near Newcastle-on-Tyne; name coined by Doyle in 1935.

T. M. Doyle

Coined the term "Newcastle disease" for NDV.

Canine parvovirus (CPV)

Parvovirus isolated in 1978; causes hemorrhagic enteritis in dogs.

Leland E. Carmichael

Co-isolated canine parvovirus and developed the first CPV vaccine.

Colin Parrish

Studied CPV evolution and vaccine efficacy.

Reston Ebola virus

Filovirus detected in Philippine pigs (2008) that can infect humans asymptomatically.

Chikungunya virus

Alphavirus responsible for Philippine outbreaks with a 573 % case rise in 2022.

H5N1 high-pathogenicity avian influenza

Subtype causing recurring outbreaks in poultry and wild birds worldwide.

Foot-and-mouth disease-free status

WHO/OIE recognition that the Philippines has been free of FMD without vaccination since 2015.

Peste des petits ruminants (PPR)

Morbillivirus disease; the Philippines declared PPR-free since 2015.

African horse sickness (AHS)

Orbivirus transmitted by Culicoides midges; the Philippines declared AHS-free in 2016.

Positive-sense RNA

Viral RNA with the same polarity as mRNA; can be directly translated by host ribosomes.

Negative-sense RNA

Viral RNA complementary to mRNA; requires transcription to positive sense before translation.

Satellite virus

Defective virus that depends on helper virus for replication.

Inclusion bodies

Aggregates of viral proteins or nucleic acids seen within infected cells.

Antigenic determinant

Specific viral protein or carbohydrate region recognized by the immune system.

Half-life of a virus

Time required for 50 % loss of infectivity; lengthens as storage temperature decreases.

Heat inactivation (virus)

Loss of infectivity by denaturing surface proteins; e.g., ASFV inactivated at 60 °C for 20 min.

pH stability range

Most viruses remain stable between pH 5–9; enveloped viruses are inactivated at pH 5–6.

Magnesium chloride stabilization

1 M MgCl₂ prolongs infectivity of picornaviruses and reoviruses.

Bacterial superinfection

Secondary bacterial infection occurring during viral disease; often treated with antibiotics.

Rifampicin

Antibacterial drug that also inhibits poxvirus assembly.

Chemical inactivants

Agents like ether, chloroform, aldehydes, and detergents used to disinfect and inactivate viruses.

Sodium hydroxide (8/1000)

Alkaline disinfectant capable of inactivating ASFV within 30 minutes.

Hypochlorite (2.3 % chlorine)

Chlorine-based disinfectant recommended for ASFV inactivation.

Formaline (0.3 %)

Aldehyde disinfectant effective against ASFV after 30 minutes.

Envelope phospholipids

Make enveloped viruses susceptible to heat, detergents, and solvents, reducing their stability.

Phospholipid proportion in viruses

Lipids comprise 20–35 % of the dry weight of enveloped viruses.

Glycoprotein

Viral envelope protein with carbohydrate chains; mediates attachment to host receptors.

Magnesium sulfate stabilization

1 M MgSO₄ enhances stability of orthomyxo- and paramyxoviruses.

Virus size range

Typical vertebrate viruses range from 17 nm (Circoviridae) to 450 nm (Poxviridae).

Poxviridae

Large DNA viruses with complex symmetry; include smallpox and ASFV relatives.

Coronaviridae

Enveloped helical RNA viruses 80–160 nm in diameter; include SARS-CoV-2.

Paramyxoviridae

Family of enveloped helical RNA viruses 150–300 nm; includes NDV.

Picornaviridae

Family of small (~30 nm) naked icosahedral positive-sense RNA viruses; includes FMDV.

Caliciviridae

Naked icosahedral positive-sense RNA viruses 35–40 nm; cause gastroenteritis.