Exotic ungulate encephalopathy See prion diseases

expressed genes The basic functional units of DNA, identified by cloning mRNAs and sequencing individual cDNAs. Also called ESTs or 'expressed sequence tags'.

Martin KJ and Pardee AR (2000) Proc Natl Acad Sci 97, 3789

expression vector A cloning vector which expresses protein from genetically inserted foreign genes. The vector normally contains a strong promoter which is inducible and a strong initiation site for translation. Both eukaryotic and prokary-otic vectors can be used; their suitability may depend upon the need for processing of the protein product (e.g. cleavage or glycosylation). Commonly used expression vectors for virus genes include those derived from Escherichia coli, Vaccinia virus, the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV) and yeast.

eye disease caused by viruses

Eyach virus (EYAV) A species in the genus Coltivirus antigenically related to Colorado tick fever virus. Isolated from ticks, Ixodes ricinus, collected near the village of Eyach in the Neckar Valley, Germany, and from I. ricinus and I. ventalloi in France. Infectivity resists treatment with ether or deoxycholate but is sensitive to chloroform at room temperature for 30 min.

Chastel C et al (1984) Arch Virol 82, 161 Rehse-Kupper B et al (1976) Acta Virol, Prague 20, 339

Table E2. Strains of Eyach virus

Eyach virus (France-577) (EYAV-Fr577) Eyach virus (France-578) (EYAV-Fr578) Eyach virus (Germany) (EYAV-Gr)

eye disease caused by viruses Viruses from at least 10 families can cause ocular disease in humans. In most cases infection spreads from the upper respiratory tract or skin.

(1) Adenoviridae. Human species cause:

(a) epidemic keratoconjunctivitis;

(b) pharyngoconjunctival fever; and

(c) acute follicular conjunctivitis.

(2) Papovaviridae. Human species causes papillomas on the lids.

(3) Herpesviridae. Human herpesvirus 1 and 2 cause keratoconjunctivitis. Varicellavirus: in chickenpox, about 4% of cases have some corneal or conjunctival involvement; in shingles, vesicles may occur on the cornea and result in scarring. In congenital cytomegalovirus infection the virus can be demonstrated in the retina at post-mortem. Ocular involvement is a rare complication of infectious mononucleosis.

(4) Poxviridae. Four species may affect the eyes: Variola virus (now eradicated), Vaccinia virus, Orf virus and Molluscum contagiosum virus.

(5) Togaviridae. Rubella virus infection during pregnancy is an important cause of congenital eye disease.

(6) Flaviviridae. Dengue and Yellow fever viruses often cause severe deep pain behind the eyes.

(7) Orthomyxoviridae. In some influenza epidemics conjunctivitis may be a common complication.

(8) Paramyxoviridae. In measles photophobia is a characteristic symptom. Mumps virus may rarely cause blindness due to nerve damage. Newcastle disease virus can cause conjunctivitis.

(9) Picornaviridae. Paralysis of oculomotor nerves can occur in poliovirus infection. Coxsackie virus A24 causes epidemic conjunctivitis, and enterovirus 70 causes acute hemor-rhagic conjunctivitis. Conjunctivitis is common in rhinovirus infections.

(10) Retroviridae. HIV causes the focal retinal ischemia (cotton-wool spots) seen in AIDS patients.

Pomerantz RJ et al (1987) New Engl J Med 317,


Ritterbrand DC and Friedberg DN (1998) Rev

Med Virol 8, 187

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