Virology PDF Notes

MYCOLOGY AND VIROLOGY LECTURE VIROLOGY WHAT ARE VIRUSES? ◦ Tropism ◦ Existing everywhere ◦ Acellular (doesn’t have any cell) ◦ Obligate intracellular (Hijack the cellular machinery of...

MYCOLOGY AND VIROLOGY LECTURE VIROLOGY WHAT ARE VIRUSES? ◦ Tropism ◦ Existing everywhere ◦ Acellular (doesn’t have any cell) ◦ Obligate intracellular (Hijack the cellular machinery of a person or a cell) ◦ Viruses do not have organelles or ribosomes ◦ Certain viruses do not have organelles or ribosomes ◦ Certain viruses further enclosed by an external lipid bilayer membrane that surrounds the capsid and may contain glycoproteins. ◦ Filterable agents: 0.01-0.3um ◦ Transcription: from DNA to RNA (mRNA) ◦ Translation: from RNA (mRNA) to protein ◦ DNA VIRUS: sa (through transcription) Nucleus papasok A GLIMPSE FROM THE PAST ◦ RNA VIRUS: sa Ribosome papasok ◦ 1796: Edward Jenner discovered the smallpox vaccine ◦ 1980: WHO declare the world free of smallpox (completely eradicated from the world) ◦ 1885: Louis Pasteur (Father of Microbiology) Scienctist discovered developed the first vaccine for rabies viruses through/by filtering ◦ 1955: Inactivated influenza vaccine it ◦ Inactivated vaccines: this are already dead viruses ◦ 1955: Jonas Salk invented the first polio vaccine Transmitted through fecal-oral, a lot of people were paralyze, in 2003 the PH were declared polio-negative kaso bumalik ◦ 1961: Albert Sabin discovered the oral polio vaccine STRATEGIES FOR FIGHTING PANDEMIC VIRUS ◦ 1982: First subunit Hepatitis B vaccine developed INFECTIONS: INTEGRATION OF VIROLOGY AND Subunit Vaccine: A portion (protein or multiple DRUG DELIVERY proteins) of Hepatitis B is injected to a person Respiratory viruses have sometimes resulted in worldwide SARS-COV2 VACCINE ROLL OUT pandemics, with the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-cov-2) being major participants. ◦ 11 Mar 2022: Covid 19 pandemic declared Long-term efforts have made it possible to control the influenza ◦ 19 Oct 2020: 212 Vaccines under development 72 virus, but seasonal influenza continues to take many lives each protein based, 27 RNA based, 50 in clinical trial year, and a pandemic influenza virus sometimes emerges. ◦ 11 Dec 2020: PDA grants Emergency Use Approval of Although vaccines for coronavirus disease 2019 (COVID-19) Pfizer BioNTech vaccine (RNA vaccine) to 16 have been developed, we are not yet able to coexist with the Sinovac: inactivated vaccine SARS-cov-2. To overcome such viruses, it is necessary to J&J: subunit vaccine obtain knowledge about international surveillance systems, ◦ 31 Jan 2023: Moderna (RNA vaccine) get full approval virology, ecology and to determine that immune responses are from US FDA effective. The information must then be transferred to drugs. Delivery systems would be expected to contribute to the rational RNA VACCINES development of drugs. In this review, virologist and drug delivery system (DDS) researchers discuss drug delivery strategies, especially the use of lipid-based nanocarriers, for fighting to respiratory virus infections. VIRUS - Use as guide ang size ng RBCS which is 6-8 um, same with the size of the bacteria which is around 1-5 um (ewan ko pano naging same yan) -Virus contain genome and protein (either DNA or RNA) -Go over na lang daw sa table -Hindi ang mRNA nag i-initiate ng immune response -mRNA will go to ribosome, ribosome will make the protein, the protein will initiate the immune response or the production of antibody NAME 1  VIROLOGY - What is more resistant? Nonenveloped virus; resistant to heat, VIRAL STRUCTURE dryness, or acid - Hepatitis A, Hepatitis E this are enteric viruses that can survive ◦ Virion is the entire viral particle the acid of the stomach (Enteric viruses or nonenveloped can ◦ Capsid is the protein coat survive GIT) ◦ Capsid (protein): give structure to the virus, protect the -Hepatitis B sensitive to heat, disinfecting materials (Enveloped genome from any harm viruses mas madali ma-disinfect compare to nonenveloped ◦ Capsomere is the protein subunit that makes up the viruses) capsid. ◦ Nucleocapsid = DNA/RNA + Protein ◦ Envelope: from a host cell's membrane. BACTERIOPHAGES VIRAL CAPSID ◦ Virus that infects only bacteria ◦ Protects the genome ◦ Phage therapy: An alternative to antibiotics in the age ◦ Facilitate host cell attachment and determines tropism of multi-drug resistance ◦ Gives the structure and shape of the virus Polyhedral: more than 10 phases sites Adenovirus: Icosahedral (20 phases) VIRAL REPLICATION Bacteriophage: only attack bacteria ◦ No ability to multiple ◦ Goal: to make new viral copies (to create genome, DNA, capsid, proteins) 1. Attachment 2. Penetration 3. Uncoating 4. Viral replication and gene expression 5. Viral assembly 6. Release GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 2  VIROLOGY 1. ATTACHMENT (ADSORPTION) 1. Attachment (Adsorption): The virus identifies and binds to a specific host cell through interactions between viral proteins and host cell receptors (tropisim) 4.VIRAL REPLICATION AND GENE EXPRESSION 4.Viral replication and gene expression: This step involves the production of viral nucleic acids and proteins, including early nonstructural proteins and late structural proteins. The synthesis process varies depending on the type of viral genome. 2. PENETRATION (VIRUS ENTRY) 2. Penetration (Virus Entry): Viruses enter the host cell via mechanisms such as fusion with the host membrane or endocytosis, leading to the formation of multinucleated cells called syncytia in some cases CLASS VI: RNA viruses that reverse transcribe like the HIV (retro viruses) CLASS I: Double stranded DNA (Normal) CLASS II: Single stranded DNA (may virus) Enzyme: RdRp (RNA dependent RNA polymerase) Methods of Penetration for Select Human Viruses Type of penetration (entry) Virus examples Clathrin-mediated Dengue virus, hepatitis C endocytosis virus, reovirus, adenovirus, parvovirus B19, West Nile virus Caveolin-mediated Human papillomavirus, Endocytosis SV40, hepatitis B virus RNA-DEPNDENT RNA POLYMERASE(RDRP) Fusion HIV, influenza, respiratory RdRP synthesizes RNA using an existing RNA strand as a syncytial virus, herpes template. This is in contrast to DNA-dependent RNA simplex viruses, dengue polymerase, which uses a DNA template to synthesize RNA. virus, Ebola virus Positive-sense RNA viruses (+ssRNA): These viruses use RdRP to replicate their genome by producing a complementary 3. UNCOATING negative-sense strand, which is then used to generate new positive-sense RNA genomes. 3. Uncoating: After entry, the viral capsid is removed to release the viral genome, which is essential for further replication Acts as mRNA, can be directly translated Triggers: increased pH in cytoplasm will disassemble and ◦ Hepatitis C virus release the RNA from RNA virus ◦ West Nile virus ◦ SARS-CoV-2 -Some RNA virus goes to the nucleus, example of it is HIV ◦ Zika virus Negative-sense RNA viruses (-ssRNA): These viruses carry RdRP GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 3  VIROLOGY within the viral particle because they must transcribe their genome into positive-sense RNA (mRNA) as the first step after infection. This mRNA is then translated into viral proteins. Requires conversion to +ssRNA before translation ◦ Influenza virus ◦ Ebola virus ◦ Rabies virus VIRAL REPLICATION This image shows how the different groups of DNA virus (ds/ss) and RNA virus (Positive sense/ Negative sense) is transcripted Lytic cycle-pinaparami ang virus into an mRNA, and this mRNA is translated into enzymes, Goal: viral reproduction to lyse the infected cell proteins to able to assemble a new virus 1. Attachment 2. Penetration 3. Uncoating 4. Viral replication and gene expression 5. Viral assembly 6. Release Lysogenic cycle Goal: viral reproduction mechanism where the viral dna is integrated in the host genome These viruses can remain inactive in host cells for long periods, evading the immune system until conditions favor reactivation (like chickenpox). Eg: Human Immunodeficiency Virus (HIV), Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV),Epstein-Barr Virus (EBV) 5. VIRAL ASSEMBLY Herpes simplex I- source: mouth Herpes simplex II- source: genital area 5. Viral Assembly: Structural proteins, genomes, and enzymes are assembled into new virus particles. This often involves acquiring an envelope during the budding process from host membranes. 6. RELEASE 6. Release: Newly formed virus particles are released either by cell lysis (destruction of the host cell) or budding, with the latter allowing the host cell to remain intact longer. Detection methods vary based on the release mechanism, with different techniques used to identify the presence of viruses in culture Picomavirus- smallest RNA virus Parvovirus- (common in dogs) smallest DNA virus GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 4  VIROLOGY Zoster Virus, Parvovirus B19, Hepatitis B Virus VIRAL MODE OF TRANSMISSION AND (HBV), Herpes Simplex Virus (HSV) EPIDEMIOLOGY ◦ Preventive Measures: ◦ Prenatal care, vaccination. Respiratory Transmission ◦ Spread through droplets when an infected person coughs, sneezes, or talks. ◦ Examples of Viruses: - Influenza, SARS, Covid-19, MERS-cov (Middle- East), Rhinoviruses. ◦ Preventive Measures: - Mask-wearing, social distancing, vaccination. Fecal-Oral Transmission ◦ Occurs when virus-laden feces contaminate food or water. ◦ Examples of Viruses: ◦ Rota virus (gastroenteritis among infants and children worldwide) Polio virus (Paralytic polio), Hepatitis A, Adenovirus, Norovirus (highly contagious in closed envt). ◦ Preventive Measures: ◦ Handwashing, safe food handling, sanitation. Sexual Transmission ◦ Spread through sexual contact or bodily fluids. EMERGING INFECTIONS: ◦ Examples of Viruses: ◦ HIV, Human T-lymphotropic Virus (HTLV), Human Oropouche virus Monkey pox Papillomavirus (HPV) causes genital warts, or in (OROV) virus (MPOX) ladies can cause cervical cancer , Herpes Simplex Virus-2 (HSV-2, ), Hepatitis B and C, Zika virus, MOT transmitted person to person ◦ Preventive Measures: primarily by biting mainly through ◦ Safe sex practices, regular testing. midge and some close contact with mosquitoes someone who has Transmission through Contaminated Objects mpox (touching, ◦ Infection through trauma or injection with contaminated sex, kissing) needles or objects. (percutaneous) ◦ Examples of Viruses: Epidemic reports 2023, Oropouche Mpox vaccination ◦ HIV, Hepatitis B and C. virus was begins in DRC ◦ Test for Hepa B: HBsAg or “surface antigen” identified as (Democratic ◦ Hepa B: endemic in the PH causing large Republic of ◦ Preventive Measures: outbreaks in Congo) after 859 ◦ Needle safety, proper disposal, and sanitation. endemic areas die this year Tissue Transplants and Blood Transfusions and new areas in World Health ◦ Viruses can be transmitted through transplanted South America. In June 2024, Cuba Organization tissues or blood products. declared outbreak ◦ Examples of Viruses: reported its first in central and ◦ Cytomegalovirus, West Nile Virus, HBV, HCV confirmed Oropouche case east Africa a ◦ Preventive Measures: global emergency ◦ Screening of donors, sterile techniques. two months ago Arthropod and Animal Bites Evaluation of ◦ Transmission through bites from infected animals or Aedes aegypti, insects. Aedes albopictus, ◦ Examples of Viruses: and Culex ◦ Rabies, West Nile Virus, Dengue, Zika virus, quinquefasciatus Oropouche virus (OROV, Cuba) Mosquitoes ◦ Preventive Measures: Competence to ◦ Vaccination for pets, insect repellent. Oropouche virus Infection Transplacental Transmission/ Vertical ◦ Viruses passed from mother to fetus during pregnancy. CYTOPATHIC EFFECTS (CPE) ◦ Examples of Viruses: ◦ Zika Virus (microcephaly) Rubella or “German - Refer to the structural and functional changes that occur in host measles” (triad: cataracts, congenital heart cells (viral culture) as a result of viral infection defects among babies, and sensorineural deafness), CMV (most common), HIV, Varicella- GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 5  VIROLOGY ◦ Henrietta Lacks (31yo African american) owner of the aggressive tumor *The cells were taken without consent :( ◦ HeLa Cells: immortalized cell line from cervical cancer cells taken from 1951 ◦ Used by Jonas Salk to discover polio virus vaccine ◦ Used to discover HPV ◦ Cancer Research ◦ Use to culture virus CULTIVATION OF VIRUSES: CELL CULTURES CULTIVATION OF VIRUSES ◦ Chick embryo for incubating avian viruses and vaccine preparation VIRAL TRANSFORMATION AND ONCOGENESIS Viral transformation certain viruses alter the genetic material of host cells, leading to uncontrolled cell growth, which can result in the development of cancer 1. Virus integrated in host cell 2. Inhibition of Tumor suppressors 3. Activation of oncogene ◦ Bacteriophage plaques 4. Chronic inflammation formed on a lawn of bacterial host cells Human Papillomavirus (HPV): - Cervical cancer, anal cancer, head and neck cancers (oropharyngeal) Epstein-Barr Virus (EBV): - Burkitt’s lymphoma, nasopharyngeal carcinoma, Hodgkin's lymphoma GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 6  VIROLOGY Poxviridae – is at the opposite end of the spectrum and is Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV): complex in nature, coding for hundreds of proteins; Does not - Hepatocellular carcinoma (liver cancer) have icosahedral symmetry; replicate in the cytoplasm Human T-lymphotropic Virus type 1 (HTLV-1) RNA VIRUSES - Adult T-cell leukemia/lymphoma (ATLL) Most RNA viruses are single stranded, half negative, Herpes virus 8 (HHV-8) enveloped, show helical capsid symmetry, and replicate in - Kaposi’s sarcoma, primary effusion lymphoma the cytoplasm - Togavirus DNA VS RNA VIRUS - Coronavirus - Retrovirus - Calicivirus - Orthomyxovirus - Paramyxovirus - Rhabdovirus - Reovirus - Picornavirus - Bunyavirus - Arenavirus - Filovirus Exception: Reoviridae are double-stranded Three are non-enveloped: Picornavirus, Calicivirus and Reovirus Five have icosahedral symmetry: Reovirus, Picornavirus, Togavirus, Flavivirus, calicivirus (Rhabdovirus has helical symmetry but shaped like a bullet) Two undergo replication in the nucleus: Retrovirus and Orthomyxovirus, HTLV DIAGNOSTIC VIROLOGY: SPECIMEN COLLECTION - Specimen selection depends on disease syndrome, suspected viral agent, and time of year. - Viruses often infect multiple tissues; symptoms may appear far from the primary infection site. - Example: Aseptic meningitis (enterovirus) detected in throat, rectal swab, or cerebrospinal fluid (CSF), Nasopharyngeal swab and Oropharyngeal swab (SARS-CoV-2) SPECIMEN COLLECTION TIMING - Collect specimens as early as possible after symptom onset. DNA VIRUSES - Virus shedding can end within 2 days in some cases. - Length of viral shedding depends on virus type, immune status, HHAPPPy (mnemonics) viruses: and patient age - Herpesvirus - Hepadnavirus - Adenovirus -Papovavirus -Parvovirus (Smallest) - Poxvirus (Largest) - Window period: time between a potential exposure to HIV infection and when an HIV test will give an accurate result with - Three have envelopes: HHP = Herpesviridae, the appearance of detectable antibodies (Test again after 1-3 Hepadnaviridae, and Poxviridae months) - Three are naked: PAP = Papovaviridae, Adenoviridae, Parvoviridae Size Largest: Poxviridae Smallest: parvoviridae Most are double stranded, show icosahedral symmetry and replicate in the nucleus DNA viruses break these rule: Parvoviridae – so simple that it only has a single strand DNA GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 7  VIROLOGY RISK GROUP Risk Group 1 (RG1): - Low individual and community risk. - Adeno-associated virus (AAV) Risk Group 2 (RG2): - Moderate individual risk with limited community risk. - Influenza virus (seasonal strains); Herpes simplex virus (HSV); Dengue virus Zika virus; Epstein-Barr virus (EBV) Adenoviruses; HBV, HIV Risk Group 3 (RG3): - High individual risk with limited community risk - Hantavirus, West Nile virus; SARS-CoV-2, Rabies virus 01 DNA VIRUS Risk Group 4 (RG4): - High individual and community risk HERPESVIRIDAE - Variola virus (Small pox), Ebola virus, Marburg virus, Lassa virus, Crimean-Congo hemorrhagic -Herpes viruses, derived from the Greek word meaning "to fever virus, Nipah virus creep” -Large (150-200 nm), double-stranded DNA, enveloped viruses. UPPER RESPIRATORY TRACT Components: Nucleic Acid Core: Contains viral DNA. - Use only synthetic fiber swabs with thin plastic or wire shafts Capsid: Protein shell that encases the viral DNA. that have been designed for sampling the nasopharyngeal Tegument: Layer of proteins that facilitate viral replication. mucosa Envelope: Lipid layer derived from the host cell membrane - Do not use calcium alginate swabs or swabs with wooden 7 herpes virus: shafts, as they may contain substances that inactivate some A. Herpes simplex virus (HSV), type 1 and 2 viruses and may inhibit molecular tests B. Varicella-zoster virus (VZV) C. Epstein-Barr virus (EBV) can cause cancer - If both NP and OP specimens are collected, combine them in D. Cytomegalovirus (CMV) under herpesviridae a single tube to maximize test sensitivity and limit use of testing E. Human herpesvirus 6 and 7 resources. F. Kaposi’s sarcoma associated herpesvirus (HHV-8) can cause cancer STORING AND SHIPPING RESPIRATORY SPECIMENS HUMAN HERPES VIRUS - Store respiratory specimens at 2-8°C for up to 72 hours after List of Human Herpes Viruses: collection - HSV-1: Primarily oral herpes. - HSV-2: Primarily genital herpes. - HSV-3 (VZV): Causes chickenpox and shingles. - HSV-4 (EBV): Associated with infectious mononucleosis and various malignancies. - CMV: Causes congenital infections and opportunistic infections in immunocompromised individuals. - HHV-6: Causes roseola in children. - HHV-7: Associated with roseola and other conditions. HHV-8: Associated with Kaposi Sarcoma. Viral transport media (VTM) A. HERPES SIMPLEX VIRUS (HSV), TYPE 1 AND 2 - allows the safe transfer of viruses, chlamydia and mycoplasma, conventional cell culture methods, HSV-1 diagnostic tests, and molecular biology techniques - Herpetic gingivostomatitis peri-oral vesiculoulcerative lesion - Recurrent herpetic gingivostomatitis: after primary infection, - Calcium and Magnesium and contains heat- the virus will remain latent for life inactivated Fetal Bovine Serum (FBS), Gentamycin (antibiotic) and Amphotericin B HSV-2 (antibody) - Genital Herpes: characterized by vesiculoulcerative lesions of - FBS: growth supplement for in vitro cell culture the penis, cervix, vulva, vagina, and perineum of the female GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 8  VIROLOGY MOT: Skin to skin contact with vesicular discharge, kissing/ sharing utensils, sexual transmission, perinatal transmission C. EPSTEIN-BARR VIRUS (EBV) (HUMAN during the time of delivery, congenital transmission HERPESVIRUS 4) VESICULOULCERATIVE LESION: - Herpesviridae Red bumps and fluid filled blisters - Pathogenesis: virus entering Pathogenesis: The virus invades the cutaneous vascular the host through the endothelium, causing epithelial cell necrosis and inflammation oropharyngeal epithelium, and leading to the formation of vesicles. The incubation period leading to lytic replication in is usually 5-6 days. epithelial cells and subsequent Latent infection: Following primary infection with HSV, the virus infection of B cells becomes localized in the sensory ganglia, either the trigeminal - EBV establishes latency in ganglion (HSV-1) or the sacral ganglion (HSV-2, where it memory B cells hindi remains latent. Individuals with latent infection remain nakakalimot kaya mabilis mag seropositive for the rest of their lives. produce ng Ag - Uncontrolled transformation of B cells results to Burkitt’s lymphom, Hodgkin’s lymphoma and nasopharyngeal carcinoma (NPC) common - Infectious Mononucleosis (Mono): young adults -Hallmark: Downey cells (reactive lymphocyte) seen in peripheral blood smears, very common among adult MOT: Saliva: kissing or sharing drinks " kissing disease" Direct Contact: With infected bodily fluids. Blood Transfusion Organ Transplantation B. VARICELLA ZOSTER VIRUS (VZV) (HUMAN Specific EBV antigens 1. Viral Capsid Antigens (VCA) Found in patients with HERPESVIRUS 4) acute phase IM 2. EBV nuclear protein (EBNA) Varicella (Chickenpox) In children 3. Early Antigen (EA) pruritic rash that progresses from macules to vesicles and - Found in cases of IM but they disappear early after eventually crusts over recovery Herpes Zoster (Shingles) In old people Heterophile Antibody Positive: ability to cross-react, can Reactivation of latent VZV leads to localized pain and a vesicular agglutinate horse or sheep erythrocyte rash among immunocompromised individuals D. CYTOMEGALOVIRUS (CMV) MOT: Airborne Transmission: Inhalation of respiratory droplets from an infected individual & Direct Contact: Exposure to fluid MOT: saliva, sexual contact, blood, transfusion, organ from vesicular lesions transplantation, transplacental route Chickenpox Shingles CMV is a leading cause of congenital infections- most common cause congenital (torch) infection in women Symptoms: Infectious mononucleosis-like illness in immunocompromised patients Heterophile Antibody Negative LABORATORY DIAGNOSIS: Detection Methods: - Viral Cell Culture: Slow-growing, requiring 1-2 weeks for results. - Serologic Tests: Detection of IgM and IgG antibodies. - Direct Antigen Detection: Rapid results. - Nucleic Acid Testing (PCR): More sensitive for both symptomatic and asymptomatic patients. - Centrifugation-Amplified Shell Vials: Allow diagnosis in 24- LABORATORY DIAGNOSIS: 48 hours. Cell Culture: Gold standard; sensitive but time-consuming. Direct Antigen Testing: Faster, less sensitive than culture. ADENOVIRUS Nucleic Acid Amplification (PCR): Highly sensitive and Definition: Medium-sized, nonenveloped viruses belonging to specific. the family Adenoviridae. GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 9  VIROLOGY - Utilizes reverse transcription to synthesize DNA Structure: from the RNA intermediate. - Hepa B: Could be chronic in nature, can cause severe liver damage, some are asymptomatic GLOBAL IMPACT OF HBV 1. Infection Rates: - Approximately 400 million people are chronically Size: 70-90 nm. Shape: Icosahedral. infected worldwide. Genome: Double-stranded, linear DNA. - Around 50 million new cases are reported Discovery: First isolated from human adenoids and tonsils in the annually. early 1950s 2. Human Transmission: CLINICAL MANIFESTATIONS OF ADENOVIRUS - Humans are the sole reservoir of HBV. INFECTION: - Transmission occurs primarily through percutaneous exposure (i.e., contact with blood or Common Diseases: blood products) - Respiratory Infections: Colds, tonsillitis, pharyngitis, and croup (narrowing of airway). TRANSMISSION MODES - Gastrointestinal Infections: Gastroenteritis Primary Routes of Transmission: (serotypes 40 and 41). - Percutaneous exposure, including needle use. - Ocular Infections (sore eyes): Conjunctivitis and Other Routes: keratitis. - Perinatal transmission (mother-to-child). Statistics: - Sexual contact with infected individuals. - Accounts for less than 5% of acute respiratory diseases in the general population. Survivability of HBV: - Up to 18% in children under 10 years old. - HBV is relatively heat stable and can survive in COMPLICATIONS : dried blood and bodily fluids for several days - Respiratory complications, especially in young children (e.g., pneumonia). VACCINATION AND BLOOD SCREENING - Concomitant ear infections (otitis media) following HBV Vaccine: respiratory illness. - A highly effective vaccine exists and is widely used globally. TRANSMISSION AND EPIDEMIOLOGY: Blood Transfusion Safety: Modes of Transmission: - Risk of HBV transmission via blood transfusion - Aerosolized droplets, contact with contaminated has become rare due to routine screening of blood secretions, stool, or surfaces products Viral Stability: - Can remain viable on surfaces for weeks at varying temperatures. Incubation Period: - Ranges from 2 to 14 days DIAGNOSTIC METHODS: Detection Techniques: - Cell culture using epithelial cell lines (A-549, HEp- 2). Characteristic cytopathic effect (CPE) seen after inoculation. Modern Testing: - Indirect fluorescent antibody (IFA) and enzyme immunoassay (EIA). - Increasing popularity of nucleic acid testing for enhanced sensitivity and rapid results. - Rapid cell culture techniques (e.g., shell vials) for quicker detection. HEPADNAVIRIDAE -Same habitat: Liver -To have hepa D you need to have hepa B - Hepatitis B virus (HBV) is the prototype virus of the -Hepa B, C, D through blood Hepadnaviridae family, named for its association with hepatitis -Hepa A&E through fecal-oral and its DNA genome. The virus is known to cause severe liver damage, contributing to significant global morbidity and mortality SEROLOGICAL MARKERS 1. Virus Structure: 1. HBsAg - Pleomorphic and enveloped virus. - Active hepatitis B - Contains circular, partially double-stranded DNA. - Acute infection and infectivity general marker of 2. Replication Mechanism: infection - Replication occurs through an RNA intermediate. 2. HBeAg GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 10  VIROLOGY - Active hepatitis B with high degree with increased Gardasil (Merck & Co.) Gardasil-9 (Merck & Co.) risk of infectivity - Circulating form of HBcAg 3. Anti-HBc IgM - Current or recent and hepatocellular acute hepatitis B; important in diagnosing during window period 4. Total anti-HBc - Current or past hepatitis B 5. Anti-HBe - Recovery from hepatitis B 6. Anti-HBs - Immunity to hepatitis B or past infection 7. HBV DNA - Acute, atypical, or occult hepatitis B; viral load may be used to monitor effectiveness of therapy PAPILLOMAVIRUSES - Papillomaviruses are small, nonenveloped, circular, double- PARVOVIRUSES stranded DNA viruses. - Parvoviruses are small, nonenveloped, icosahedral, Abundance in Nature: single-stranded DNA viruses - Found in humans, dogs, cattle, monkeys, and Origin of Name: other species. Derived from Latin parvus, meaning "small." Tissue Tropism: - HPVs have a specific tissue tropism for cutaneous Distribution: (skin) or mucosal (mucous membranes) tissue. Found widely among warm-blooded animals, with some being Family: epizootic (affecting only animals). - Part of the Papillomaviridae family, which includes human papillomaviruses (HPVs). PARVOVIRUS B-19: THE HUMAN PATHOGEN Diseases Caused: -Erythroid-progenitor cells (love niya ang RBCs) - In humans, HPVs cause warts and are associated Virus Characteristics with certain cancers. - Nonenveloped, icosahedral, and appears Sexually Transmitted Genotypes: spherical under electron microscopy. - More than 30 sexually transmitted genotypes, with Replication Sites: 15–20 causing virtually all cases of cervical - Replicates in erythroid progenitor cells, mainly in cancer. adult bone marrow and fetal liver (important in fetal Types Causing Cancer: erythropoiesis). - HPV-16 and HPV-18 cause over 60% of cervical cancer cases. - HPV-16 is also linked to oropharyngeal and penile cancer in males. - Can cure through vaccination HPV CLINICAL PRESENTATIONS Common Wart Associations: - HPV-1: Plantar warts (feet) - HPV-2 and HPV-4: Common warts on hands - HPV-6 and HPV-11: Genital warts Types 16 and 18 are responsible for most cases of cervical cancer and certain oral cancers. DISEASES ASSOCIATED WITH PARVOVIRUS B-19 Fifth Disease (Erythema Infectiosum): DETECTION METHODS - A common childhood exanthem, characterized by Histopathologic and Cytologic Examination: Biopsies and a red rash. cell samples are used for identification. Aplastic Crisis: DNA Probe Assays: For genotyping specific HPV strains. - Aplastic: cells were lyse FDA-Approved Vaccines: Cervarix (Glaxo Smith Kline) GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 11  VIROLOGY - Occurs in individuals with hemoglobinopathies (e.g., sickle cell disease). 3 Fetal Infection (Hydrops Fetalis): - Resulting from transplacental infection, can lead to fetal complications. Example of erythroid-progenitor cells: normoblast, orthochromatic normoblast, erythrocytes OTHER POXVIRUSES INFECTING HUMANS Molecular Diagnostics: - RT-PCR: Rapid diagnostic tool for monkeypox. - Traditional PCR & RFLP: Used for diagnosing molluscum contagiosum and parapoxviruses. Challenges: - Limited availability of molecular tests for some poxviruses (e.g., molluscum contagiosum). Continued Research: - Diagnostic tools, vaccines, and antiviral therapies remain areas of ongoing development. POLYOMAVIRUSES - Small, nonenveloped, circular, double-stranded DNA viruses. -affects the brain and nerves POXVIRUSES Poly: Multiple Largest and Most Complex Viruses: Oma: Tumor Poxviruses are large, double-stranded DNA viruses, Human polyoma virus 2 visible under a light microscope due to their size (200-400 nm). JC virus (John Cunningham) and BK virus (from a renal transplant patient). Distinct Shape: Bk Virus: Hemorrhagic cystitis Virions are oval or brick-shaped. MOT: Transplantation Bk virus in HSC causes bladder inflammation then bladder mucosal bleeding JC virus: Progressive multifocal leukenecepahalopathy (PML) in the brain Clinical relevance: Risk factors: JC virus among immunocompromised individuals Smallpox (variola virus) is a historically significant virus from this Virus spreads via blood to brain oligodendrocytes, astrocytes family. causing lysis and myelin sheath loss OTHER POXVIRUSES INFECTING HUMANS 1. Molluscum Contagiosum Virus: - Causes small clusters of lesions in humans. - Spread via direct contact or fomites 2. Monkeypox: - Causes a smallpox-like illness but with lower mortality (Congo Basin clade: up to 12%). - Transmitted through the oropharynx, nasopharynx, or skin abrasions. - First U.S. outbreak in 2003, traced to imported rats. 3. Orf Virus - Transmitted from sheep to humans through direct contact. - Causes nodules, mainly on the hands, and resolves within 4–6 weeks. 1 2 GUTIERREZ, AZHIA MAE (BSMLS-3 LCH) 12