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Transcript
Herpes Viruses Epstein-Barr virus Cytomegalovirus 1 5/4/2017 CMV & EBV Outline Structure Classification Multiplication Clinical manifestations Epidemiology Diagnosis Control 2 Baron’s Web Site 5/4/2017 Latent Infections ALL herpes viruses can establish latent infections. The viral genome may become incorporated into the host DNA or remain extrachromosomal Latent viruses can be reactivated by stress, menstruation or uv light Reactivation may be asymptomatic or lead to mild or severe disease. 3 5/4/2017 Herpes Diagnosis Isolation of virus by tissue culture herpevirinae cause cytopathic effects intranuclear fluorescence of scrapings using fluorescent antibodies PCR being developed CMV retiniitis is diagnosed clinically 4 5/4/2017 Epstein Barr Virus 5 5/4/2017 Epstein-Barr virus virus established in lymphoid tissue and salivary glands - is excreted from salivary glands. Epstein-Barr virus is a transforming DNA virus. 6 5/4/2017 EBV History infectious mononucleosis, first described more than 100 years ago. in 1958, Michael Burkitt discovered that a malignant tumour, Burkitt’s lymphoma, was infectious. in 1959, Michael Epstein and Yvonne Barr cultured a virus from tumours that showed typical herpes-like morphology. 7 5/4/2017 EBV and Burkitt’s lymphoma were shown to be the same virus when a lab technician acquired mononucleosis while working with the Burkitt’s lymphoma virus. 8 5/4/2017 EBV Diseases Infectious mononucleosis lymphoproliferative cancer in heart and bone marrow transplant recipients Burkitt’s lymphoma (B cell carcinoma) in E. africans nasopharyngeal carcinoma in Chinese 9 5/4/2017 Classic Mononucleosis infectious mononucleosis has an incubation period of 30 to 50 days. high fever, malaise, myalgia, cervical lymphadenopathy, splenomegaly, hepatomegaly high fever, pharyngitis, grey-white pharyngeal exudate, skin rash atypical lymphocytosis or leucocytosis: infected B cells, T cells (suppresser and cytotoxic) recover due to a strong cell-mediated response 10 5/4/2017 Complications Carcinoma Burkitt’s lymphoma (B cell carcinoma) Nasopharyngeal carcinoma. if there is an immune deficiency especially of T cells - the host is highly susceptible to Epstein-Barr virus. 11 5/4/2017 Infectious Mononucleosis Diagnosis clinical symptoms differential blood count - lymphocytosis, neutropenia, large atypical cells. heterophile antibodies antibodies to EBV nuclear antigen antibodies to EBV capsid antigen 12 5/4/2017 Infectious Mononucleosis Transmission direct oral contact exposure to saliva fomites arthropod vectors 13 5/4/2017 Exposure early in Africa and Asia, later in industrialized countries 70% of college age persons have never had exposure - very susceptible to the virus. 95% of middle aged adults are seropositive. 14 5/4/2017 Portal of Entry oropharynx attaches to the epithelium moves to the Parotid gland viremia latent in throat and blood subclinical 15 asymptomatic 5/4/2017 Epstein-Barr Virus - Symptoms sore throat, high fever, cervical lymphadenopathy, grey-white pharyngeal exudate, skin rash, enlarged liver and spleen. Leucocytosis: infected B cells, T cells (suppresser and cytotoxic) recover due to a strong cell-mediated response (T cell). 16 5/4/2017 Cancer Transformation of the cell by virus Helper virus if the transforming virus is defective Co-carcinogen, chemical, cigarette smoke 17 5/4/2017 Transformed cells: lose contact inhibition continue to divide form random aggregations can become invasive Not warts: Papovavirus 18 5/4/2017 Primary Hepatocellular Carcinoma Icteric symptoms: jaundice, dark urine, pale stools Highest incidence: Central Africa Southeast China Pacific Islands, Borneo, Sarawak, Taiwan 250,000 to1,000,000 deaths worldwide per year U.S.A. 5000 deaths / year 19 5/4/2017 Human T-cell Leukemia Virus HTLV1 & HTLV2 retroviruses with no oncogenes Adult T-cell leukemia and lymphoma - Southern Japan, Carribean Islands, West Africa 20 5/4/2017 Epstein Barr Southern China, Asia suspect co-carcinogen: - nitrosamines in salted fish oncogenes not reported. 21 5/4/2017 Burkitts Lymphoma East Africa, Papua New Guinea at risk: 6 -14 year old males tumor of immature B-cells 22 5/4/2017 Human Papillomavirus cervical, penile, vulval, and rectal cancer viral genome integrated into host genome Co-carcinogens - cigarette smoke - HSV herpes 23 5/4/2017 Cytomegalovirus 24 5/4/2017 Cytomegalovirus Urine isolate 25 5/4/2017 Intranuclear inclusions The cell swells and a large inclusion body forms in the nucleus. 26 5/4/2017 Cytomegalovirus Nuclear & cytoplasmic inclusions 27 5/4/2017 Transmission: CMV not highly infectious, virus found in saliva, urine and blood. infants and children acquire CMV from other children. congenital. In utero, at birth during perinatal period. 28 5/4/2017 Congenital: CMV 29 the following possibilities relate to the congenital type. severe deformities and death. survive with serious defects - physical and mental. survive with out deformities. newborns: - Enlarged liver and spleen, jaundice, capillary bleeding, microcephaly, ocular inflammation. 5/4/2017 Disseminated cytomegalovirus fever, severe diarrhea, hepatitis, arthritis, pneumonia, high mortality. activation of inapparent infection. also due to: immunosuppressive therapy. cancer. AIDS. 30 5/4/2017 Virus in blood or organ: post transfusion. post organ transplant. 31 5/4/2017 Cytomegalovirus mononucleosis: teenage, young adult similar to other mono. 32 5/4/2017 Transmission: saliva, respiratory mucus, milk, urine, semen, cervical secretions, feces and lymphocytes. 33 5/4/2017 Differential Diagnosis: the differential diagnosis in neonates must include toxoplasmosis, rubella, herpes simplex, bacterial sepsis. in adults it must be differentiated from Epstein-Barra and hepatitis A & B. 34 5/4/2017 Laboratory diagnosis: CMV virus can be grown from all organs. many serological tests. 35 5/4/2017 Treatment: CMV gancyclovir, foscarnet, hyperimmune CMV immunoglobulin, have some effect. interferon does not prevent infection or promote recovery. 36 5/4/2017 Prevention:CMV no animal can be found that can be infected with CMV. Two deterents: vaccine stimulated antibodies may not be protective. Patients already seropositve can be reinfected. a vaccine could be oncogenic. 37 5/4/2017 Epidemiology of CMV 40-100% positive for the antibodies. newborns 7.5% positive in the USA & UK. woman of child bearing age were 20-100% positive in many countries that were studied (pregnant virus in the urine). IV drug users were 100% positive for the antibodies. homosexual males were 30% positive for the antibodies - high percentage shed virus. 38 5/4/2017