SEPARATED Viral Infections, Vector Borne Illnesses, and Vaccines

Viruses are

-no cells but obligate intracellular parasites

-can't independly replicate, synthezise their own proteins or energy

-composed of internal core DNA or RNA

Viral envelope

Lipoprotein composed of lipid from a host cell

Viral tropism

the ability of a virus to infect a specific cell or tissue type leading to a specific disease process

nucleic acid (DNA or RNA) is surrounded by

-protein coat (capsid) to form nucleocapids

-icosahedral and helical

Capsid and surface proteins

-protet genome from nucleases

-mediate attachment to cell receptor

-provide antigens for vaccination and immune system

-viruses with several serotupes are differentiated by surface proteins

Viral serotypes medical implications

-if infected with one serotype, you can get different serotypes of same virus

-vaccines contain protection to ALL serotypes to convey complete immunity

-hard to form vaccine against virus that constantly alters the antigens it expresses

viral envelopes

-lipoprotein membrane composed of lipid from host cell during budding (acquired during replication and virus specific proteins)

-antigen expression->serotype and immunity implications

-more sensitive to heat, drying, detergents and alcohol

Non-enveloped virus

-spread during direct contact or animal bites

-moist environments

-transmited through fecal oral route or body fluids

Stages of viral replication

Early: attach, penetration, uncoating

Middle: mRNA synthesis, protein synthesis/processing, genome replication

Late: assembly and release

DNA Viruses replication

nucleus of the host cell

-requries RNA polymerase

RNA viruses replication

cytoplasm

-retroviruses have signle stranded RNA which is transcribed into double stranded DNA by Reverse transcriptase (HIV)

Viral protein synthesis and replication

-mRNA is synthesized and translate by host ribosomes into viral proteins

-replicated viral genome and capsid proteins are packaged together to form progeny viruses

Non-envelope viral release

rupture the cell and release mature particles

Enveloped viral release

Budding from the host's cell membrane

Horizontal transmission

person to person

vertical transmission

parent to child

vector borne and animal reservoir transmission

animal to human (mosquito or animal bite)

Stages of infection

1. incubation (asymptomatic)

2. prodromal (non specific symptoms)

3. Specific illness (characteristic symptoms)

4. Recovery, chronic disease, latent disease

Provirus Model (viral tumorigenesis)

tumor-producing genes enter the cell at the time of infection by the Tumor Virus

Oncogenic Virus Model (viral tumorigenesis)

Malignant genes pre-exist within the cell prior to infection (allows inactive genes to become active-overproduction of growth factors)

Human T cell lymphoma virus (medically relevant tumor viruses)

adult t cell leukemia/lymphoma

Human Herpes Virus 8 (medically relevant tumor viruses)

Karposi's Sarcoma

Human Papillomavirus (medically relevant tumor viruses)

Cervical and penile cancer

Hepatitis B + C (medically relevant tumor viruses)

Associated with hepatocellular carcinoma

Epstein-Barr Virus

Assiciated with Burkitt's Lymphoma and Nasopharylgeal Carcinoma

Herpes virus structure

enveloped double stranded DNA

-budding from membrane

Type of infection herpesviruses cause

-Latent infection, can reactivate

-due to immunosuppression

Herpesviruses human pathogens

HSV-1+2

HHV 3-7

-HHV 4 is EBV

-HHV 5 is cytomegalovirus

KSHV (HHV-8)

herpes life cycle

-envelopes fuses with cell membrane and nucleocapside travels to nucleus

-DNA inserted and replicated, proteins form

-Treatment: Acyclovir and valvcylovir

Cytomegalovirus (CMV) transmission

Vertical and horizontal transmission

-MC congenital disease

-MC transmission is in utero

CMV disease

Healthy: asymptomatic

Immunocompromised: pneumonitis, esophagitis, Hepatitis, retinitis

-Diagnosis: PCR, histology

-antivirals

Epstein-Barr Virus transmission

Saliva

-affected B lymphocytes

Epstein-Barr virus causes what diseases?

Infectious mononucleosis and hairy leukoplakia (whitish hair on lateral tongue)

EBV associated diseases, dx, tx

-Burkitts lymphoma and nasopharyngeal carcinoma

-diagnosis with Monospot or lymphocytosis

-supportive care

Humans Herpesvirus 6 symptoms

Roseola Infantum

-young children (daycares)

-High fever

-defervenscene followed by rash of face and trunk

-immunocompromised: antitrivals

Human herpesvirus 8 causes

inactivation of tumor suppressor gene

-sex and saliva, organ transplant

HHV-8 disease

-Kaposi sarcome

-many dark purple flat/nodular lesions of skin, oral cavity, soles, GI tract, lungs

-biopsy

-HAART (antiviral)

Measles Virus (rubeola) structure

enveloped single stranded RNA

-respiratory droplets

Mealses Virus symptoms

-rhinorrhea, cough

-Koplik's Spots (bright red lesions with central dot on buccal mucosa)

after prodromal^ phase →

Rash on face which spreads to lower extremities (palms and soles too)

complication: encephalitis

Measles diagnosis/treatment

-Clinical or PCR

-Supportive care

-vaccination to prevent

Mumps Virus Structure

Enveloped single stranded RNA

-respiratory droplets

Mumps symptoms

-swelling of salivary glands

-anorexia, fever, malaise

-painful orchitis

Mumps virus diagnosis + treatment

-clinical, PCR

-supportive care

-vaccine to prevent

Rubella Virus Structure

Enveloped single stranded RNA

-respiratory or vertical

Rubella Virus symptoms

-face rash and then extremities (x3 days)

-posterior auricle lymphadenopathy

-shorter/fainter than rubeola

-Congenital rubella: cataracts, ductur arteriosus, developmental delayR

Rubella diangosis and treatment

-clinical, PCR

-supportive care

-Vaccine to prevent

Parvovirus B19 structure

Non-enveloped single stranded DNA virus

-infected erythoblasts and endothelial cells

Parvovirus Transmission

Respiratory droplet and vertical transmission

Parvovirus symptoms

Erythema Infectiosum

-bright red rash of cheeks/trunk, rhinorrhea

-arthritis

-only symptomatic if chronic anemia

Chronic B19 infection

chronic anemia

Parovovirus B19 diagnosis/treatment

-IgM antibodies

-supportive care

Human Papillomavirus structure

Non-enveloped viruses with double stranded DNA

-squamous epithelial cells

-direct (skin to skin)

HPV symptoms

Cauliflower like lesions (skin/genital warts)

HPV Diagnosis

Koliocytes (Vacuolated Cells) on biopsy

HPV treatment

-Topical, liquid nitrogen, surgery

Skin and Plantar warts

HPV 1-4

Genital Warts (HPV)

HPV-6 and HPV-11

Premaglignant lesions and cervical carcincoma, penial cacinoma and anal carcinoma

HPV-16 and HPV-18

HPV prevention

-Immunization (Gardasil-9)

-safe sex

-circumcision

-screening for cancer (pap smear)

human immunodeficiency virus (HIV) structure

Enveloped Retrovirus

HIV transmission

Sexual and blood-borne contact

vertical transmission

HIV related disease

Acquired Immunodeficiency Syndrome (AIDS)

HIV cell specific infection

CD4 Lymphocytes

HIV pathophysiology

1. go 120 binds to CD 4 on T helper cell

2. envelope fuses to cell membrane and genome enters cell

3. Reverse transcriptase turn RNA into DNA

4. Integrase mediates integration of DNA into Host DNA

5. DNA transcribed forming RNA for genome and is tranlated into viral proteins

6. New viruses is assembled and buds from affected cell via viral protease

HIV stages

Acute Stage (2-4 weeks): lethargy, generalized lymphadenopathy, rash (no palms or soles)

Latent Stage (7-11 years): asymptomatic

Immunodeficient Stage (AIDS): CD4 declines

CD4 cells >500

normal to non-infected

CD4 cells 350-499

Thrush, Hairy Leukoplakia, Molluscum Contagiosum

CD4 cells 200-349

Karposi Sarcoma

CD4 cells 100-199

Pneumocystis jiroveci, candida esophagitis

CD4 cells <100

Toxoplasma encephalitis, CMV Retinitis

HIV treatment and prevention

-Antirival

-no vaccine

-PEP (needle stick-ASAP) or PrEP (many sex partners, at high risk)

West Nile virus reservoir

Wild birds

-MC neuroinvasice arboviral disease

West Nile virus transmission

Culex mosquito to human

west nile symptoms and treatment

-asymptomic

-fever, headache

-supportive care

Dengue Virus transmission

-Aedes aegypti mosquito

Dengue Virus Reservoir

Humans and monkeys

classic dengue fever symptoms

dengue Fever (breakbone fever)

Malaise

Severe arthralgia and myalgias

Dengue Hemorrhagic Fever symptoms

Classic Dengue

Hemorrhage

Hemorrhagic Shock

Dengue virus treatment

-supportive care

Lyme disease pathogen

Borrelia burgdorferi

Lyme disease vector

Ixodes tick (deer tick)

Lyme disease stage 1 symptoms (3-30 days)

Erythema Migrans (bull's eye) 75% of people

Flu-like symptoms

Lyme disease stage 2 (weeks-months)

Myocarditis, Meningitis, Bell's Palsy, Peripheral Neuropathy

Cardiac/neurologyc involvement

Lyme Disease stage 3

Arthritis of the large joints

encephalopathy

Early Lyme Disease Treatment

Doxycycline

Late Lyme disease treatment

ceftriaxone

Rocky Mountain Spotted Fever pathogen

Rickettsia rickettsii

Rocky Mountain Spotted Fever transmission

Dermacentor variabilis (dog tick)

Rocky Mountain Spotted Fever symptoms

fever

H/A

Myalgias

Rash after 2-6 days

Rocky Mountain Spotted Fever treatment

Doxycycline

Malaria Pathogen

Plasmodium spp.

P. falciparum (most severe symptoms)

-destructs RBC

Malaria transmission

female anopheles mosquito

Malaria symptoms

abrupt fever

chills

H/A

Myalgias

Arthralgias

Splenomegaly

Jaundice

P. falciparum malaria treatment

NO Chloroquine

-Coartem or Malarone

Active immunity

immunity from developed of immunoglobulins through vaccine

Passive immunity

provided by administration of preformed immunoglobulins

Passive-active immunity

get vaccine and immunoglobuns for immune response (RABIES)

Capsular-polysaccharide vaccine

-Strep pneumoniae

-Pneumovax 23: PCV 15 or 20 (older than 65)

-Neisseria meningitis

-Hib

Pneumonia vaccine old regimen

Child: PCV 13

adult: above 65, PCV 13 then pneumovax after 1 year

Pneumonia vaccination new regimen

Child: PCV 15 or 20

Adult: older than 65, PCV 15, 20, or 21 if 15 then pneumovax 23 after 1 year