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Bohomolets Microbiology Lecture #14

Bohomolets Microbiology Lecture #14



By Ms. Kostiuk from Microbiology department

By Ms. Kostiuk from Microbiology department



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  • Herpesvirus* was named for the tendency of some herpes infec­tions to produce a creeping rash. Like other enveloped viruses, herpesviruses are prone to deactivation by organic solvents or detergents and are rel­atively unstable outside the host's body.
  • Approximately half of all adenovirus infections are asymptomatic. As for treatment, there is no antiviral therapy
  • Certain serotypes of human adenoviruses cause sarcomas at the site of injection in laboratory rodents such as newborn hamsters and transform rodent cells in culture. There is no evidence that adenoviruses cause tumors in human, and no adenoviral DNA has been detected in the DNA of any human tumor cells.
  • Herpesvirus* was named for the tendency of some herpes infec­tions to produce a creeping rash. Like other enveloped viruses, herpesviruses are prone to deactivation by organic solvents or detergents and are rel­atively unstable outside the host's body.
  • The virion obtains its envelope by budding through the nuclear membrane and exits the cell via tubules or vacuoles that communicate with the exterior. In the latently infected cells, multiple copies of HSV-1 are found in the cytoplasm of infected neurons.
  • The relationship between varicella (chickenpox) and zoster (shingles) and the clinical appearance of each is exist. First contact with the virus (usually in childhood) results in a macular, papular, vesicular rash distributed primarily on the face and trunk, (b) The virus becomes latent in the dorsal ganglia of nerves that supply dermatomes of mid-thoracic nerves and the cranial nerves that supply facial regions, and as result we can see the clinical appearance of shingles. Early symptoms are acute pain in the nerve root and redness of the dermatome, followed by a vesicular-papular rash on the chest and back that is usually asymmetrical and does not cross the midline of the body
  • Wherever human popula­tions have been tested, a relatively high percentage (40-100%) have shown the presence of antibodies to CMV developed during a prior infection. Studies in the United States and the United Kingdom revealed infection in 7.5% of newborns, making CMV the most prevalent viral infection in the fetus. Transmission of CMV usually involves intimate exposure such as sexual contact, vaginal birth, transplacental infection, blood transfusion, and organ transplanta­tion. As with other herpesviruses, CMV is commonly carried in a latent state in various tissues. Because of the association of HHV-6 with cases of brain infection and encephalitis, it has been considered as a potential cause of chronic neurological disease. Researchers have recently established a link between this virus and multiple sclerosis (MS).
  • Most healthy adults and children with primary CMV infection are asymptomatic. However, three groups that develop a more virulent form of disease are fetuses, newborns, and immunodeficient adults.
  • the cytomegaloviruses* (CMVs), are named for their tendency to produce giant cells with nuclear and cytoplasmic inclusions. These viruses, also termed salivary gland virus and cytomegalic inclusion virus
  • Direct oral contact and contamination with saliva are the principal modes of transmission. Transmission by means of blood transfusions and organ transplants is also possible. The nature of infection depends on the patient's age at first exposure, socioeconomic level, geographic region, and genetic predisposition. In less-developed regions of the world, infection rates are generally higher and infection occurs at an earlier age. Children living in eastern and west-central Africa are predisposed to Burkitt's lymphoma, and residents of parts of China and North Africa show high levels of nasopharyngeal carcinoma, another tumor linked to EBV. In industrialized countries human usually develop infectious mononucleosis.

Bohomolets Microbiology Lecture #14 Bohomolets Microbiology Lecture #14 Presentation Transcript

  • DNA viruses Adenoviridae Herpesviridae
  • Family Adenoviridae 10 Neat cattle 1 Horse 4 Pig 2 Dog 2 Mouse 27 Monkey 49 Human Mast-adenovirus 14 Bird Avi-adenovirus Types Hosts Genus
  • Adenoviruses
    • DNA viruses
    • Genome – double-stranded linear DNA
    • DNA consist of 30 genes
    • 10 structural proteins are known
    • Nonenveloped
    • Icosahedral shape
    • Cubical type of symmetry
    • Size – approximately 80 nm in diameter
    • Capsid consist of 252 capsomers (240 hexons and 12 pentons on the tops)
    • Virion contain special protein-hemagglutinins (fibers) protruding from each of the 12 vertices of the capsid
    • Viruses replicate in the nucleus, form intranuclear inclusions
  • Scheme of adenovirus structure Capsid proteins DNA
  • Adenovirus structure
  • Electron micrographs of adenovirus particles
  • Electron micrographs of adenovirus Hole virions Hemagglutinins (fibers)
  • Electron micrographs of adenovirus
  • Models of adenovirus
  • Events of adenovirus reproduction
    • Attachment to the cell via fiber
    • Penetration by viropexis
    • Uncoating
    • Viral DNA moves to the nucleus
    • Transcription of early genes by using host cell DNA-depend RNA-polymerase
    • Synthesis of early nonstructural proteins in the cytoplasm
    • Replication of viral DNA in the cell nucleus
    • Transcription of late mRNA and translation of late structural proteins
    • Assembly of virions in the nucleus
    • The viruses are released by lysis of the cell
  • Routs of transmission:
    • Aerosol droplet
    • Fecal-oral
    • Direct inoculation of conjunctivas
    • Affected tissues :
    • Respiratory tract (both upper and lower)
    • Gastrointestinal tract
    • Conjunctivas
    • Genitourinary tract
  • Human diseases caused by adenoviruses Serotype of virus Diseases 2 Affection of heart 3, 7, 21 Affection of CNS (meningitis, encephalitis) 38, 40, 41 Infantile gastroenteritis with nonbloody diarrhea 40, 41 Hemorrhagic cystitis 8, 19, 37 Epidemic keratoconjunctivitis 2, 3, 5, 7, 21 Conjunctivitis 4, 7 , 14, 21 Acute respiratory disease 3, 4, 7, 14 Pharyngitis, pharyngoconjunctival fever 1, 2, 5, 6 Epidemic disease in children
  • Classification of adenoviruses according to their oncogenisity 1, 2, 5 і 6 С – nononcogenic 3, 7, 11, 14, 21 В – lowly oncogenic 12, 18, 31 А – highly oncogenic Serotype of virus Class of oncogenisity
  • Laboratory diagnosis of adenoviral infections
    • Rapid detection – detection of viral antigens in affected cells with immunofluorescens reaction
    • Virological method – isolation of viruses in cell culture and identification ( CPE and serological tests – complement binding test, inhibition of hemagglutination test, virus neutralization test )
    • Serological diagnostic – detection of a 4-fold or greater rise of antibody titer (complement binding test)
    • Genodiagnostic – polymerase chain reaction
  • Adenoviral CPE Normal cells HeLa Swelling, rounding of cell, clustering
  • Herpesviruses
  • Division of herpesviruses according to hosts, susceptible to the viruses
    • Human – 8 species
    • Primates – 31 species
    • Other mammalians – 31 species
    • Birds – 12 species
    • Reptiles – 6 species
  • Herpesviruses
    • DNA viruses
    • Genome – double-stranded linear DNA
    • DNA consist of approximately 80 genes that code 80 proteins
    • Enveloped
    • Icosahedral symmetry of nucleocapsid
    • Size – 120-200 nm in diameter
    • Virion does not contain a polymerase
    • Viruses replicate in the nucleus, form intranuclear inclusions
    • Herpesviruses are the only viruses that obtain their envelopes by budding from the nuclear membrane
    • Have tendency to cause latent infections with periodically recurrent acute conditions
  • Structure of herpesvirus virion Nucleocapsid Tegument Genome Envelope Glycoprotein spike І type Glycoprotein spike І I type
  • Kaposi’s sarcoma virus Genome Capsid Envelope Tegument
  • Particles of herpesviruses
  • Chickenpox virions
  • Herpesvirus virions
  • Herpesvirus virions without envelope
  • Adherence of herpesviruses on the cell membrane
  • Events of hepresvirus reproduction
    • Penetration
    • Uncoating
    • Released viral DNA enters the nucleus
    • Transcription with host cell polymerase
    • Synthesis of early nunstructural protein in cytoplasm
    6. Replication of viral DNA in the cell nucleus 7. Synthesis and transportation of late structural proteins in the nucleus 7. Assembly of nucleocaplid
  • Strategy of herpesvirus DNA synthesis
  • Events of hepresvirus reproduction 8. 9. 10. 11. 12.
  • Release of herpesviruses Egression of herpesviruses from the nucleus Egression of herpesviruses from the cell
  • Release of herpesviruses from the infected cell
  • Herpesviridae family classification
    • Subfamilies:
    • Alpha-herpesvirinae (  -herpesvirinae)
    • Betha-herpesvirinae (  -herpesvirinae)
    • Gamma-herpesvirinae (  -herpesvirinae)
  • Subfamily Alpha-herpesvirinae Varicello - virus Simplex - virus Genus Varicella (chickenpox), herpes zoster (shingles) Herpes zoster virus (VZV) Herpes genitalis, encephalitis, herpes of newborn , carcinoma of cervix Herpes simplex virus type 2 (HSV-2) Gingivostomatitis , herpes labialis, encephalitis, keratitis (ocular herpes) Herpes simplex virus type 1 (HSV-1) Diseases Viruses
  • Herpes simplex viruses 1, 2. Diseases and affected tissues
  • Recurrent lesions of herpes labialis (coldsore)
  • Herpesviral gingivostomatitis
  • Herpesviral gingivostomatitis
  • Neonatal herpes simplex
  • Genital herpes Vesicles
  • Chickenpox Disseminated chicken pox lesions on the back
  • Chickenpox Disseminated chicken pox lesions on the face
  • Chickenpox in the child
  • Varicell-Zoster viral infections Chickenpox Zoster (shingles)
  • Zoster (shingles)
  • Subfamily Betha-herpesvirinae Roseolo - virus Cytome - galovirus Genus Human herpesvirus- 7 Acute febrile disease – roseola, chronic neurological disease , Hodgkin’s lymphoma, oral carcinoma, and T-cell leukemia Human herpesvirus-6 (human T-limphotropic virus) Cytomegalovirus mononucleosis, congenital CMV infection, perinatal CMV infection Cytomegalovirus (CMV) Diseases Viruses
  • CMV infection characteristic Immuno-deficient adults Newborns Fetuses Affected objects Systemic disease with fever, severe diarrhea, hepatitis, pneumonia, and high mortality Sexual contact, blood transfusion CMV mono-nucleosis Chiefly asymptomatic, although pneumonitis and a mononucleosis-like syndrome can develop during the first 3 months after birth During exposure to the mother’s vagina Perinatal CMV infection Most infected newborns are born without signs, a certain number exhibit enlarged liver and spleen, capillary bleeding, microcephaly. In some cases death follows within a few days or weeks. Rarely - sequelae, including hearing and visual disturbances and mental retardation. Trans-placental Congenital CMV infection Features Trans-mission Form of infection
  • Cells infected by CMV Giant cell Nucleus Normal cell
  • Subfamily Gamma-herpesvirinae Rhadino - virus Lympho - cryptovirus Genus Kaposi’s sarcoma (a common tumor of AIDS patients). Possible: multiple myeloma, cancer of the blood Human herpevirus 8 (or Kaposi’s sarcoma-associated herpesvirus) Infectious mononucleosis, Burkitt’s lymphoma, nasopharyngeal carcinoma. Hairy leucoplakia (in AIDS patients) Epstein-Barr virus (EBV) Патологія Viruses
  • Infectious mononucleosis Angina when infectious mononucleosis The symptoms of infectious mononucleosis are sore throat, high fever, and cervical lymphadenopathy, which develop after a long incubation period (30-50 days). Many patients also have a gray-white exudate in the pharynx
  • Burkitt’s lymphoma Burkitt’s lymphoma is a B-cell malignancy that usually develops in the jaw and grossly swells the cheek. African children 4 to 8 years old are usually affected
  • Nalopharyngeal carcinoma
    • is a malignancy of epithelial cells that occurs in older Chinese and African men
  • Blood smear of healthy human
  • Blood smear of a patient with infectious mononucleosis. Lymphocytes infected by EDV
  • Important features of common herpesvirus infections Via respiratory secretions Zoster Cranial or thoracic sensory ganglia Varicella VSV Sexual contact, perinatal infection Herpes genitalis Lumbar or sacral sensory ganglia Herpes genitalis, perinatal herpes HSV-2 Via respiratory secretions and saliva Herpes labialis, encephalitis, keratitis Cranial sensory ganglia Gingivo-stomatitis HSV-1 Route of transmission Recurrent infection Usual site of latency Primary infection Virus
  • Important features of common herpesvirus infections Intrauterine infection, transfusions, sexual contact, via secretions (eg, saliva and urine) Asymptomatic shedding Uncertain Congenital infection, mono-nucleosis CMV Via respiratory secretions and saliva None B lympho-cytes Infectious mono-nucleosis EBV Route of transmission Recurrent infection Usual site of latency Primary infection Virus
  • Common methods of laboratory diagnosis of herpesviral infections
    • Virological . Isolation of viruses in the chicken embryo and cell culture and following identification (detection of CPE and serological tests)
    • Serological diagnostic – detection of a 4-fold or greater rise of antibody titer
    • Genodiagnostic – polymerase chain reaction
  • CPE caused by herpersiruses (syncytium formation)
  • Chicken embryos that infected by herpesviruses Herpes simplex virus I type Herpes simplex virus II type
  • Oncogenic DNA viruses
    • Viruses that cause cancer in human:
      • Papillomaviridae
      • Herpesviridae
      • Hepadnaviridae
    • Viruses that cause cancer only in laboratory animal and in cell culture (not in human):
      • Adenoviridae
      • Polyomaviridae
  • Smallpox
  • Poxvirus
  • Papillomaviruses