2Human Papilloma viruses (HPV) DNA virus, double strand, circular, Icosahedral nucleocapsid, small size (45-55nm). No envelope
3Human Papilloma virus (HPV) 70 different types (HPV-1 to HPV-70).It replicates only in the nucleus of epithelial cells. Infection occurs in skin and mucosal surfaces.HPV are species-specific.
4They are transmitted by contacts (both direct and indirect). HPVSome cause warts and some others are associated with cancer.They are transmitted by contacts (both direct and indirect).
5Wart (Condylomata accuminata by HPV-2, -3, -10) Resembling a cauliflower or a solid blister by producing excess cells.Mucocutaneous lesions: Hands, feet, genital area and even other locations.A small, rough benign tumor
6Common wart:HPV-2, -3 and -10(on knees and fingers)
19HPV & Cervical CancerThe agents: HPV16 & HPV18 responsible for 70% of all cervical carcinoma.Starts with a flat area of dysplasia (visible as a white plaque).Cervical and anal-cervical carcinoma is associated with persistent HPV infections.
20HPV Pathogenesis (1)It infects cells in the basal layers of the skin or mucosa.Common period: 1-6 monthsViral antigen and infectious virus is produced when the cells begin to become squamifed and keratinized.Several months later, the wart may regress.
21HPV Pathogenesis (2)Cell mediated immunity (CMI) responses are more important in recovery.In immunocompromised patients (e.g. post transplant), there may be warts as a result of reactivation.
22Diagnosis Diagnosis is clinical HPV cannot be cultivated in the laboratorySerological tests are neither useful nor available
23Treatment Removing warts by surgery. Using keratolytic agents: - Salicylic acid (to soften and cause desquamation of epithelium or horny layer of skin).Removing warts by surgery.Destruction of wart tissue by freezing with dry ice (solid CO2) or with liquid nitrogen.Using Podophyllin (a resinous powder obtained by precipitating an alcoholic tincture of the rhizome of American Mayapple)
24Structure: Polyoma viruses DNA virus, double strand, circular, Icosahedral nucleocapsid, small size (45-55nm). No envelopeWell-known Human polyoma viruses: JC and BK (all around the world)
25JC and BK virusesThey can be remained in kidney & lymphoid tissues after a primary infection.They can be reactivated after kidney transplantation or pregnancy or oldness.
26Clinical findingsPolyomavirus (BK) nephropathy usually happens in 5% of kidny recipients and causing rejection in 50% of them.BK hemeoragic cystitis in patients with bone morrow transplantation.JC is the agent of PML (progressive multiphocal locoencephalopaty) in immune deficiency involving 5% of AIDS cases.
31Parvoviruses- Unusual requirements for replication: either a helper virus (a helper adenovirus) or rapidly dividing cells.The virus replicates when cell growth cycle is in “S” stage (when host DNA replication produces two identical sets of chromosomes.)Virus replication is in nucleus of the cell.
32B19A parvovirus replicating in erythroid precursor cells, so the main place for virus replication is: fetal bone marrow and liver.Favorite receptor on erythrocytes: p Ag (Globoside).B19 can be found in blood and respiratory secretions.It can transmit from mother to embryo.
33B19 A human virus which cannot pass to animals. The virus interrupts the production of erythrocytes in embryo causing sever anemia and abortion.Erythema infectiosum, (fifth disease), is the commonest clinical manifestation of B19 virus infection.In children (age 5-15) and sometimes adults (up to 30) % infections are asymptomatic.
34Fifth disease (Erythema infectiosum) First stage:7-8 days after infection, a prodromal influenza-like illness, characterized by headache, malaise, chills.Second stage:17 to 18 days after infection, the development of a mild feverish illness and a maculopapular rash. It starts with erythema of the cheeks (Slapped cheek) followed by a rash (resembling the rash of rubella) on the trunk and limbs. These symptoms disappeared 1-3 weeks.
42Anemia & aplastic crisis The virus infects erythroid precursor cells in the bone marrow and leads to anemia. Sever anemia in blood disorders (e.g. in Sickel cell anemia, Leukemia or hemolytic anemia)It leads to erythroid aplasia (Aplastic crisis) in patients with hemolytic anemia or immune deficiency, such as people with transplantation event.Anemia and aplastic crisis is self-limiting.
43Diagnosis Detecting viral DNA in serum (PCR) A rise in parvovirus-specific IgM or IgG.Bone marrow examination shows an absence of erythroid precursors.
44TransmissionB19 is anywhere, all through the year, different ages, sporadic or epidemic.Spread through respiratory secretions, vertical transmission from motherMany cases are subclinical.
45Control and treatment There is no antiviral therapy or vaccine Most infections are asymptomaticThe anemia is self-limiting, but blood transfusion support is required until the bone marrow recovers.Antiserum decreases symptoms.Sanitation