virology

Viruses Relevant to DentistryDNA Viruses

Papova viruses
Human Papilloma virus: Human and Animal (70serotypes) Skin warts: Benign epith. tumor, more common in children transmitted by direct contact Oral squamous papilloma: small (1 cm) peduculated exophytic lesion, occurs in 3rd -5th decades, predominant in male

Verrucous carcinoma: Evidence of virus associated tumor. Malignant changes in virus induced warts. Associated with HPV-16,18,33 with cervical cancer. Development of vulvas warts in women with lymphoma.

Adenoviruses

Spread by Resp. & ocular secretion, human is main reservoir. latent infection of tonsils, adenoid, lymphoid tissues. Infection is acute and self limiting. Acute Resp. Dis.: influenza like seen in military camps chara. by pharyngitis & conjunctivitis. self limiting complication: pneumonia Pharyngoconjuctivitis: disease of infants. Epidemic keratoconjuctivitis: Pneumonia and Gastroenteritis:

Herpes Viruses

dsDNA affect human and animals. Human Herpes viruses (1-8) structurally similar. (HSV-1, HSV-2, VZV, CMV, EBV, HHV-6, 7,8) Affect skin, neurons, lymphoid tissue. Latent, reactivation, teratogenic tendancies

Herpes simplex virus types 1 & 2 (HSV-1, HSV-2)

Two types differentiated by serotyping & DNA technology. Causes either primary or reactivation of recurrent virus.


Primary infections
Primary gingivostomatitis: lip lesion and mouth Genital herpes: vesicles on genitalia; HSV-2 & less by HSV-1 Herpetic whitlow: finger infection (common in Dentists) Conjuctivitis & keratitis: eye blindness Encephalitis: primary or recurrent death

Recurrent infections

reactivation of latent virus in neurons by menstruation, stress, sunlight, local trauma. Infection at the site of primary infection: Bell`s palsy, Herpes labialis

Epidemiology of HSV

Virus acquired by contact with lesion HSV-1 orofacial lesion (above the belt) HSV-2 genital lesion (below the belt) STD Recurrent is common in presence of circulating Ab cell to cell spread

Diagnosis of HSV

Clinical Direct : EM IF multinucleated gaint cell

Prevention & Treatment

Avoid contact with secretion (asymptomatic carrier) Acyclovir Should be given at prodromal phase

Varicella Zoster Virus (VZV)

Varicella (chicken pox) primary one virus Zoster (Shingles) reactivation

Chicken Pox

Childhood self limiting, more sever in adults Clinical signs: i.p. 2 weeks fever vesicles on m.m and skin.

Shingles

Means belt, Reactivation from TG, affect adults. Reactivation despite Abs (trauma, neoplastic, drugs, immunosuppression). Vesicles on the skin supplied by sensory nerve (painful) Involvement of ophthalmic, maxillary & mandibular nerves confused with toothache Involvement of tympanic mem. Ramsay Hunt Syn Involvement of facial nerve facial palsy

Epidemiology of VZV

Transmission direct contact droplet infectionVaricella……………..childhoodZoster……………….adult

Diagnosis & Treatment of VZV

Diagnosis clinical HSV-1 serological Treatment & Prevention chicken pox self limiting symptomatic treat. Zoster acyclovir Passive immunization with VZ Ig in sever infection

Primary gingivostamatitis

Primary gingivostamatitis

Primary gingivostamatitis

Primary gingivostamatitis

Encephalitis

keratoconjuctivitis

Herpetic whitlow

Recurrent Herpes

Recurrent Herpes Labialis

Bell`s palsy

EM & giant cell of VZV

Distribution of rash in chickenpox

Rash of chickenpox

Lesion & scarring of chiken pox

Vesicles of chicken pox

Chicken pox pneumonia

Varicella in disturbed immunity

Rash & erythema of VZV

Pustules & crusts of VZV

Cervical & Thoracic VZV

Postherpetic neuralgia

Thoracic VZV

Ophthalmoplegia & facial paralysis

Epstein-Barr virus (EBV)

Primary in lymphocytes (B lymphocytes)4th herpes viruses causes:Infectious mononucleosis: glandular fever Burkitt’s lymphoma: (Africans) BLNasopharyngeal carcinoma: (chinees) NPCPost transplant lymphoproliferative diseases


Infectious mononucleosis
Acute affect lymphoid tissues of young adults (15-20) Transmitted by saliva (kissing disease) i.p. 4-7 wks characterized by: Fever, Lymphadenopathy, Leukocytosis (with abnormal monocytes), Tonsillitis, Fatigue, hepatospleenomegaly

Infectious mononucleosis virus

Clinical features of IM

Anginose variety if IM

Rash of IM Versus Ampicillin rash


Diagnosis of IMIF……IgMHematology…abnormal monocytesPaul Bunell test (agglutination of sheep or horse RBCsTreatment: symptomatic

Burkitt’s lymphoma Malignant tumor of african children Common in area endemic with malaria Malaria damage RES


Nasopharyngeal carcinoma Tumor in southern chinees Hairy leukoplakia Thicking of lateral border of tongue DNA of EBV in epithelial cells Not malignant Common in AIDS patients


Cytomegalovirus
Infection occurs Immunocompromised patients Infected fetus during pregnancy Diseases: congenital abnormalities (deafness, mental retardation) 2. minority show different illness (salivary, brain, lung, kidney and liver infection) Postnatal infection (activated by pregnancy, blood transfusion, immunosuppression)

Cytomegalovirus:P

Cytomegalovirus: K


Epidemiology route is not clearDiagnosis and TreatmentTissue culture, IF, DNA hybridizationSerology is not recommendedGanciclovir is the drug of choiceAcyclovir does not work…why?

Human herpes virus-6 (HHV-6)

Closely related to CMV Isolated from peripheral blood of AIDS patient Virus presents in saliva Common in childhood causing: Raseola infantum cha. fever &facial rash Mononucleosis cha. Lymphadenopathy (cervical)

Human herpes virus-7 and 8 (HHV-7, HHV-8)

Recently identified HHV-7 is T-lymphotropic virus causes rash HHV-8 causes Kaposi sarcoma in AIDS patients

HHV-8 oral lesion

HHV-8 skin lesion