Herpesviridae

Herpesviridae
Herpesviridae EM PHIL 2171 lores.jpg
Virus classification
Group: Group I (dsDNA)
Family: Herpesviridae
Genera

Subfamily Alphaherpesvirinae
   Simplexvirus
   Varicellovirus
   Mardivirus
   Iltovirus
Subfamily Betaherpesvirinae
   Cytomegalovirus
   Muromegalovirus
   Roseolovirus
Subfamily Gammaherpesvirinae
   Lymphocryptovirus
   Rhadinovirus
Unassigned
   Ictalurivirus

The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans.[1] [2] [3] The family name is derived from the Greek word herpein ("to creep"), referring to the latent, recurring infections typical of this group of viruses. Herpesviridae can cause latent or lytic infections.

Contents

Viral structure

Herpes viruses all share a common structure—all herpes viruses are composed of relatively large double-stranded, linear DNA genomes encoding 100-200 genes encased within an icosahedral protein cage called the capsid which is itself wrapped in a lipid bilayer membrane called the envelope. This particle is known as the virion.

Herpes virus life-cycle

All Herpes viruses are nuclear-replicating—the viral DNA is transcribed to RNA within the infected cell's nucleus.

Infection is initiated when a viral particle contacts a cell with specific types of receptor molecules on the cell surface. Following binding of viral envelope glycoproteins to cell membrane receptors, the virion is internalized and dismantled, allowing viral DNA to migrate to the cell nucleus. Within the nucleus, replication of viral DNA and transcription of viral genes occurs.

During symptomatic infection, infected cells transcribe lytic viral genes. In some host cells, a small number of viral genes termed latency associated transcript (LAT) accumulate instead. In this fashion the virus can persist in the cell (and thus the host) indefinitely. While primary infection is often accompanied by a self-limited period of clinical illness, long-term latency is symptom-free.

Reactivation of latent viruses has been implicated in a number of diseases (e.g. Shingles, Pityriasis Rosea). Following activation, transcription of viral genes transitions from latency-associated LAT to multiple lytic genes; these lead to enhanced replication and virus production. Often, lytic activation leads to cell death. Clinically, lytic activation is often accompanied by emergence of non-specific symptoms such as low grade fever, headache, sore throat, malaise, and rash as well as clinical signs such as swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells.

Human herpesviridae infections

There are eight distinct viruses in this family known to cause disease in humans.[4] [5]

Human Herpesvirus (HHV) classification[4][1]
Type Synonym Subfamily Primary Target Cell Pathophysiology Site of Latency Means of Spread
HHV-1 Herpes simplex virus-1 (HSV-1) α (Alpha) Mucoepithelial Oral and/or genital herpes (predominantly orofacial) Neuron Close contact
HHV-2 Herpes simplex virus-2 (HSV-2) α Mucoepithelial Oral and/or genital herpes (predominantly genital) Neuron Close contact (sexually transmitted disease)
HHV-3 Varicella zoster virus (VZV) α Mucoepithelial Chickenpox and shingles Neuron Respiratory and close contact
HHV-4 Epstein-Barr virus (EBV), lymphocryptovirus γ (Gamma) B cells and epithelial cells Infectious mononucleosis, Burkitt's lymphoma, CNS lymphoma in AIDS patients,
post-transplant lymphoproliferative syndrome (PTLD), nasopharyngeal carcinoma, HIV-associated hairy leukoplakia		 B cell Saliva (kissing disease)
HHV-5 Cytomegalovirus (CMV) β (Beta) Monocyte, lymphocyte, and epithelial cells Infectious mononucleosis-like syndrome,[6] retinitis, etc. Monocyte, lymphocyte, and ? Close contact, transfusions, tissue transplant, and congenital
HHV-6 Roseolovirus, Herpes lymphotropic virus β T cells and ? Sixth disease (roseola infantum or exanthem subitum) T cells and ? Respiratory and close contact?
HHV-7 Roseolovirus β T cells and ? Sixth disease (roseola infantum or exanthem subitum) T cells and ?  ?
HHV-8 Kaposi's sarcoma-associated herpesvirus
(KSHV), a type of rhadinovirus		 γ Lymphocyte and other cells Kaposi's sarcoma, primary effusion lymphoma, some types of multicentric Castleman's disease B cell Close contact (sexual), saliva?


Zoonotic infections

In addition to the Herpes viruses considered endemic in humans, some viruses associated primarily with animals may infect humans. These are zoonotic infections:

Zoonotic Herpesviruses
Species Type Synonym Subfamily Human Pathophysiology
Macaque monkey CeHV-1 Cercopithecine herpesvirus-1, (Monkey B virus) α Very unusual, with only approximately 25 human cases reported.[7] Untreated infection is often deadly; sixteen of the 25 cases resulted in fatal encephalomyelitis. At least four cases resulted in survival with severe neurologic impairment.[7][8] Symptom awareness and early treatment are important for laboratory workers facing exposure.[9]
Mouse MHV-68 Murine gammaherpesvirus-68 γ Zoonotic infection found in 4.5% of general population and more common in laboratory workers handling infected mice.[10] ELISA tests show factor-of-four (x4) false positive results, due to antibody cross-reaction with other Herpes viruses.[10]


Animal herpesviridae

In animal virology the most important herpesviruses belong to the Alphaherpesvirinae. Research on pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, has pioneered animal disease control with genetically modified vaccines. PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection, and for unravelling molecular mechanisms of herpesvirus neurotropism, whereas bovine herpesvirus 1, the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis, is analyzed to elucidate molecular mechanisms of latency. The avian infectious laryngotracheitis virus is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae.[2] [3]

Taxonomy

The following genera are included here:

Research

Research is currently ongoing into a variety of side-effect or co-conditions related to the herpes class of viruses. These include:

|!Type!|!Conditions!| | HSV1 | Alzheimer's disease, Artherosclerosis | | HSV2 | Multiple Sclerosis | | HSV3 / Cytomegalovirus | Crohn's disease, Cholangio Carcinoma, Pancreatic Cancer, Pancreatitis | | HSV4 / Epstein-Barr Virus | Fibromyalgia, Dysautomnia |

References

  1. ↑ 1.0 1.1 Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0838585299. 
  2. ↑ 2.0 2.1 Mettenleiter et al (2008). "Molecular Biology of Animal Herpesviruses". Animal Viruses: Molecular Biology. Caister Academic Press. ISBN 978-1-904455-22-6. 
  3. ↑ 3.0 3.1 Sandri-Goldin RM (editor). (2006). Alpha Herpesviruses: Molecular and Cellular Biology. Caister Academic Press. ISBN 978-1-904455-09-7 . http://www.horizonpress.com/ahv. 
  4. ↑ 4.0 4.1 Whitley RJ (1996). Herpesviruses. in: Baron's Medical Microbiology (Baron S et al, eds.) (4th ed. ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.chapter.3567. 
  5. ↑ Murray PR; Rosenthal KS; Pfaller MA (2005). Medical Microbiology (5th ed. ed.). Elsevier Mosby. ISBN-13: 978-0-323-03303-9; ISBN-10: 0-323-03303-2. 
  6. ↑ Bottieau E, Clerinx J, Van den Enden E, Van Esbroeck M, Colebunders R, Van Gompel A, Van den Ende J (2006). "Infectious mononucleosis-like syndromes in febrile travelers returning from the tropics.". J Travel Med 13 (4): 191–7. PMID 16884400. 
  7. ↑ 7.0 7.1 Weigler BJ (February 1992). "Biology of B virus in macaque and human hosts: a review". Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 14 (2): 555–67. PMID 1313312. 
  8. ↑ Huff J, Barry P (2003). "B-virus (Cercopithecine herpesvirus 1) infection in humans and macaques: potential for zoonotic disease". Emerg Infect Dis 9 (2): 246–50. PMID 12603998. 
  9. ↑ Herpes-B Fact Sheet
  10. ↑ 10.0 10.1 Hricova M, Mistrikova J (2007). "Murine gammaherpesvirus 68 serum antibodies in general human population". Acta virologica 51 (4): 283–7. PMID 18197737. 
  11. ↑ Fenner, Frank J.; Gibbs, E. Paul J.; Murphy, Frederick A.; Rott, Rudolph; Studdert, Michael J.; White, David O. (1993). Veterinary Virology (2nd ed.). Academic Press, Inc. ISBN 0-12-253056-X. 

External links

Diseases of the skin and appendages by morphology
Growths
Epidermal
verruca, clavus, seborrheic keratosis, acrochordon, molluscum contagiosum, actinic keratosis, squamous cell carcinoma, basal cell carcinoma, merkel cell carcinoma, nevus sebaceous, trichoepithelioma
Pigmented
ephelis, lentigo, melasma, nevus, malignant melanoma
Dermal and subcutaneous
epidermal inclusion cyst, hemangioma, dermatofibroma, keloid, lipoma, neurofibroma, xanthoma, Kaposi's sarcoma, infantile digital fibromatosis, granular cell tumor, leiomyoma, lymphangioma circumscriptum, myxoid cyst
Rashes
With epidermal involvement
Eczematous
essential dermatitis, contact dermatitis, atopic dermatitis, seborrheic dermatitis, stasis dermatitis, lichen simplex chronicus, Darier's disease, glucagonoma syndrome, langerhans cell histiocytosis, lichen sclerosus, pemphigus foliaceus, Wiskott-Aldrich syndrome, Zinc deficiency
Scaling
psoriasis, tinea corporis, tinea cruris, tinea pedis, tinea manuum, tinea faciale, pityriasis rosea, secondary syphillis, mycosis fungoides, systemic lupus erythematosus, pityriasis rubra pilaris, parapsoriasis, icthyosis
Blistering
herpes simplex, herpes zoster, varicella, bullous impetigo, acute contact dermatitis, pemphigus vulgaris, bullous pemphigoid, dermatitis herpetiformis, porphyria cutanea tarda, epidermolysis bullosa simplex
Papular
scabies, insect bite reactions, lichen planus, miliaria, keratosis pilaris, lichen spinulosus, transient acantholytic dermatosis, lichen nitidus, pityriasis lichenoides et varioliformis acuta
Pustular
acne vulgaris, acne rosacea, folliculitis, impetigo, candidiasis, gonococcemia, dermatophyte, coccidioidomycosis, subcorneal pustular dermatosis
Hypopigmented
tinea versicolor, vitiligo, pityriasis alba, postinflammatory hypopigmentation, tuberous sclerosis, idiopathic guttate hypomelanosis, leprosy, hypopigmented mycosis fungoides
Without epidermal involvement
Red
Blanchable Erythema
Generalized
drug eruptions, viral exanthems, toxic erythema, systemic lupus erythematosus
Localized
cellulitis, abscess, furuncle, erythema nodosum, carcinoid syndrome, carcinoma erysipeloides, fixed drug eruption
Specialized
urticaria, erythema multiforme, erythema migrans, erythema gyratum repens, erythema annulare centrifugum, erythema ab igne
Nonblanchable Purpura
Macular
thrombocytopenic purpura, actinic purpura
Papular
Indurated
scleroderma/morphea, granuloma annulare, lichen sclerosis et atrophicus, necrobiosis lipoidica
Miscellaneous
Ulcers
Hair disorders
telogen effluvium, androgenic alopecia, trichotillomania, alopecia areata, systemic lupus erythematosus, tinea capitis, loose anagen syndrome, lichen planopilaris, folliculitis decalvans, acne keloidalis nuchae
Nail disorders
onychomycosis, psoriasis, paronychia, ingrown nail
Mucous membrane disorders
aphthous stomatitis, oral candidiasis, lichen planus, leukoplakia, pemphigus vulgaris, mucous membrane pemphigoid, cicatricial pemphigoid, herpesvirus, coxsackievirus, syphilis, systemic histoplasmosis, squamous cell carcinoma
Microbiology: Virus topics
Components
Viral envelope · Capsid
Other
Table of clinically important viruses · Bacteriophage · Virus cancer link · Laboratory diagnosis of viral infections · Antiviral drug · Neurotropic virus · Oncovirus
Baltimore (virus classification)
DNA
RNA
RT