Pathogenic DNA Viruses PDF

Pathogenic DNA Viruses  DNA Viruses Herpes Enveloped Non-enveloped Double- Double- Single- stranded stranded stranded genome genome g...

Pathogenic DNA Viruses  DNA Viruses Herpes Enveloped Non-enveloped Double- Double- Single- stranded stranded stranded genome genome genome Poxviruses Adenoviruses Parvoviruses Herpesviruses Polyomaviruses Hepadnaviruses Papillomaviruses  Herpesviridae Large family of enveloped dsDNA viruses Virus enters cell through envelope fusion with cell membrane Envelope of new virus particles derived from nuclear membrane Members show latency (some integrate into genome) - Reactivate due to aging, chemotherapy, immune suppression, physical or emotional stress  Herpesviridae 8 members infect humans HSV-1 (aka HHV-1) – herpes simplex 1 HSV-2 (aka HHV-2)– herpes simplex 2 VZV (aka HHV-3)– varicella zoster virus CMV (aka HHV-5)– cytomegalovirus EBV (aka HHV-4)– Epstein-Barr virus HHV-6 – herpesvirus 6 – roseola HHV-7 – herpesvirus 7 HHV-8 – herpesvirus 8  Viruses can be latent in trigeminal, brachial or sacral ganglia On reactivation, travel down nerve cells to cause lesions  HSV1 Infections Infections in early childhood Oral herpes (cold sores, fever blisters) - Tingling prior to outbreak - Painful itchy lesion forms on lips, crusts over and heals in a few days Herpatic gingivostomatitis - Usually seen in young immunocompromised patients - Fever, sore throat, swollen lymph nodes Herpatic keratitis (ocular herpes) - Conjunctivitis, pain, light sensitivity  HSV2 Infections Infections typically age 14-29 Cause of most cases of genital herpes and 10% of oral cold sores Initial outbreak flu-like symptoms such as fever, body aches, swollen lymph nodes Recurrent outbreaks usually less severe Can spread in absence of lesions  Herpes of the Newborn Caused by HSV1 and HSV2 Potentially fatal - can be infected in utero or more commonly at birth Delivery by Caesarian section if active outbreak at time of birth  Diagnosis, Treatment and Prevention Visual presence of lesions; microscopic examination Treatment: valacyclovir, acyclovir, famciclovir; topical medications