Perch hyperplasia virus PHV A tentative

species in the genus Epsilonretrovirus. Sequence analysis of the pol gene showed a phylogenetic similarity to the type species, Walleye dermal sarcoma virus.

perch iridovirus An iridovirus was isolated from pike-perch, Stizostedion lucioperca, fingerlings with no sign of disease.

Tapiovaara H et al (1998) Dis Aquat Org 32, 185

perch rhabdovirus An unassigned member of the genus Lyssavirus, family Rhabdoviridae. Isolated from yearling perch, Perca fluviatilis, in France. Causes a CNS disorder with low mortality in young perch inoculated intracranially.

percid herpesvirus 1 (PeHV-1) An unas-signed virus in the Herpesviridae family. First reported in 1980 in association with skin lesions (epidermal hyperplasia) in spawning walleyes, Stizostedion vitreum vitreum, in Canada. So far only found in fish from Bad Carrot River, Saskatchewan. Significance in fish populations is unclear.

Synonyms: Walleye epidermal hyperplasia virus; herpesvirus vitreum.

Yamamoto T et al (1985) Fish Pathol 20, 361

perdicid herpesvirus 1 (PdHV-1) An unas-signed virus in the Herpesviridae family. Isolated in 1979 from the liver of bob-white quail, Colinus virginianus, in Germany. The quail had probably died from Clostridium colinum infection (quail disease). A herpesvirus was isolated from the birds in chick embryo fibroblast cultures. Using neutralization tests, there was no cross-reaction between this virus and antisera against Marek's disease virus, or herpesviruses from duck, turkey, chicken, parrot, owl, falcon, pigeon, cormorant or stork. The only cross-reaction was with crane herpes-virus. The role of this virus in disease in quail or other species is not known. Synonyms: herpesvirus colinum; bob-white quail herpesvirus.

Kaleta EF et al (1980) Arch Virol 66, 359

Pergamino virus A strain of Andes virus, in the genus Hantavirus. Isolated in Pergamino, Argentina from the rodent, Akodon azarae.

perinatal infections Virus infections acquired by the neonate during delivery or shortly thereafter. The placenta provides a powerful barrier that allows transit of maternal IgG to the fetus whilst preventing a large number of infective agents from reaching the embryo or the fetus. However, the neonate may be exposed to a number of harmful viruses during passage through the birth canal or from breast milk.

Table P1. Viruses causing perinatal infection

Cytomegalovirus

Herpes simplex virus

Human immunodeficiency virus

Hepatitis B virus

Hepatitis C virus

Human papillomavirus

Enders G (1998) In Virology, vol. 1 of Topley & Wilson's Microbiology and Microbial Infections, Ninth edition, edited by BWJ Mahy and L Collier. London: Arnold, p. 873

Perinet virus (PERV) A tentative species in the genus Vesiculovirus. Isolated from Culex antennatus in Madagascar. Could be the same as Andasibe virus.

Clerc Y et al (1983) Ann Virol (Inst Pasteur) 134E, 61

perinuclear Situated in the region between the two membranes of the nucleus or close to the outer membrane. Herpesviruses develop in the nucleus

Pestivirus from immature capsids containing newly synthesized DNA which can then be observed budding through the inner nuclear membrane into the perinuclear space. Certain rhabdoviruses which are thought to bud through one nuclear membrane accumulate in the perinuclear space; members of the Reoviridae replicate in the cytoplasm near the outer nuclear membrane.

periodic disease A syndrome involving episodes of relatively benign symptoms (fever, lymphadenopathy) at intervals of 2-3 weeks for more than 10 years. Associated with chronic Epstein-Barr virus infection.

Lekstrom-Himes JA et al (1995) Clin Infect Dis 22, 22

permissive cells Cells in which replication of a particular virus can take place.

Peromyscus virus A possible species in the genus Paramyxovirus. Isolated from the pooled tissues of four wild white-footed mice, Peromyscus leucopus, trapped in Virginia, USA. Replicates in embryonated eggs and a variety of cell cultures with CPE. Infected cells hemadsorb guinea pig erythrocytes. Kills suckling mice on i.c. injection and hamsters on i.c. or i.p. injection. Antibodies are found in some humans and in wild Peromyscus sp but not in laboratory mice or other wild animals.

Morris AJ et al (1963) Proc Soc Exp Biol Med 113, 276

peroxidase An enzyme that catalyzes reactions in which hydrogen peroxide is an electron acceptor. Used as a reporter molecule in immunodiagnostic techniques such as ELISA.

persistent fraction Synonym for non-neu-tralizable fraction.

persistent infection The term encompasses a wide range of pathological processes in cell cultures and whole animals. In general the term is best described as including infections in which a degree of equilibrium is established between the virus and the host. In an animal host the chronic pathological process may or may not progress, with or without fluctuation in severity. Infective virus is intermittently or always recoverable. In cell cultures there are three types of persistent infection: carrier cultures, steady-state infection and a third in which the viral genome is integrated with the cell genome.

Ahmed R and Chen ISY (1999) Persistent Viral Infections. New York: John Wiley and Sons, 725 pp

Mahy BWJ et al (editors) (1982) Virus Persistence, SGM Symposia vol. 33. Cambridge: Cambridge University Press ter Meulen V (1994) Semin Virol 5, 259

Peste des petits ruminants virus (PPRV) A

species in the genus Morbillivirus. Causes an important disease of sheep and goats in West and Central Africa, the Middle East and southern India. Similar to rinderpest but cattle are not affected. There is pyrexia with nasal and ocular discharge, necrotic stomatitis, and later severe enteritis and pneumonia. Mortality may be over 90%. Antigenically related to distemper, Measles and Rinderpest viruses but distinct from them. Rinderpest vaccine can be used to prevent this disease. Non-pathogenic for cattle, although infection gives immunity to Rinderpest virus. Replicates with CPE in a variety of cell cultures but sheep and goat cells are more sensitive. CPE develops 6-15 days after infection. Syncytia are formed. There are cytoplasmic and intranuclear inclusions. Synonyms: Kata virus; pseudorinderpest virus; stomatitis/pneumoenteritis complex virus.

Barrett T (1999) In Encyclopedia of Virology, Second edition, edited by A Granoff and RG Webster. London: Academic Press, p. 1559

Pestivirus A genus of the family Flaviviridae. Antigenically unrelated to viruses in other genera of the family. No invertebrate host. Spherical virions 40-60nm diameter. The virion envelope has 10-12 nm ring-like subunits on its surface. Contain a positive-strand RNA genome about 12.3 kb long with no 3' poly A or 5'-terminal cap. There is a single large open reading frame which encodes a polyprotein of about 4000 amino acids. Four structural proteins are encoded toward the 5' terminus: a basic nucleocapsid protein, p14; and three envelope glycoproteins, gp48, gp25 and

Pestivirus

gp53. In addition, at least seven non-structural proteins are formed by cleavage of the polyprotein. Only species affecting domestic and wild mammals (pigs and ruminants) have so far been recognized. Type species Bovine diarrhea virus 1. Other species in the genus are Bovine diarrhea virus 2, Border disease virus and Classical swine fever virus.

Becher P et al (1997) J Gen Virol 78, 1357 Meyers G and Thiel H-J (1996) Adv Virus Res 47, 53

van Rijn PA et al (1997) Virology 237, 337

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