Microbiology diseases/viruses

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Human Immunodeficiency Virus (HIV)

Retrovirus (transcriptase + integrase)

Phospholipid envelope (from host)

Receptors: CD4 + T cells

Gp120 glycoprotein spikes

Modes of transmission: sex, blood, needles, mother/fetus

Avoids by: being latent, moving from cell-cell, high rate of mutation

Prevention: Antiretroviral Therapy (ART) —> multiple drugs, lower viral load

• patients are more prone to opportunistic infections + Kaposi’s sarcoma

When CD4 T cells drops to 200 cells they are in the AIDS phase

NO VACCINEEEE

Measles (Rubeola)

Respiratory route

Highly contagious 

Diagnosis: Koplik’s spots appear inside cheek, rash

Complications: acute measles encephalitis, SSPE

Prevention: MMR vaccine (not for pregnant women)

Rubella (German Measles) (Teratogenic)

Respiratory route

Symptoms: rash, light fever

Prevention: MMR vaccine 

Teratogenic: If cross placenta —> Congenital rubella syndrome: fetal damage, deafness, heart defects, mental retardation

Chickenpox

Respiratory route

Caused by Varicella-Zoster Virus (VZV), Human Herpesvirus-3 (DNA, latent)

Cause pus-filled vessicles

Can cause Reye’s Syndrome —> severe chickenpox, vomitting and brain dysfunction

Becomes latent in root ganglia —> can be activated and cause Shingles

Prevention: live attenuated vaccine

Shingles

Reactivation of latent Varicella-Zoster Virus (VZV) that moves from ganglia along peripheral nerves

Highest incidence in older adults, due to stress/low immunity

Painful pustular lesions over dermatome; limited to one side of the body

Prevention: Singrix Vaccine

Smallpox

Respiratory route —> moves into bloodstream and infects organs and skin

Highly contagious, humans are only host

Completely eradicated by vaccination

Potential bioterrorism agent

Monkeypox

Transmitted from human to human contact or Zoonotic (animals)

Less severe smallpox

Primarily affects men to men sex

Prevention: smallpox vaccine

Herpes Simplex Virus (HSV) (Teratogenic)

Belongs to Human herpesvirus (HHV)

Recurrences from viruses latent in nerve ganglia 

• caused by sun, stress, hormones, weak immune system

Virus can be shed without symptoms present

Complications: Herpes encephalitis (spreads to brain), Neonatal Herpes (infant brain/eye damage, death)

Type 1 —> spread through oral contact causing cold sores or fever blisters

• not canker sores 

Type 2 —> Spread sexually, genital herpes

Human papillomaviruses (HPV) (oncogenic)

Transmitted via contact

Causes common warts 

Most infect skin (common warts), some infect mucous membranes (genital warts) —> can cause cancer in high-risk mucosal types (oncogenic)

Prevention: Gardasil 9 , the nine-valent HPV vaccines but doesn. not treat existing infection

Epstein Barr Virus (EBV) (oncogenic)

Transmitted via saliva

Human herpesvirus 4 —> latency in B lymphocytes

Infects B cells and causes Mono 

Almost universally present in human adults 

Oncogenic Complications: Burkitt’s lymphoma (Cancer), Nasopharyngeal carcinoma

Cytomegalovirus (CMV) (Teratogenic)

Transmitted across placenta, sexually, blood, saliva, tissue

Human herpesvirus 5 —> latency in leukocytes

Infects leukocytes, birth defects

Causes Cytomegalic inclusion disease (CID) in newborns

• intellectual diasbilites or hearing loss

Poses a threat to immunocompromised patients

• Life-threatening pneumonia

• Cytomegalovirus retinits: eye infection

Rhinovirus

Most common cause of the common cold

Thrives in low temp

Some caused by Coronavirus

Mild symptoms: sneezing, nasal secretion, congestion, cough, aches

Antibiotics don’t work, must use antiviral drugs

Influenza (flu)

RNA Virus (eight RNA segments) —> no proof-reading (mutations)

Structure: envelope, protein capsid, two spikes 

Antigenic drift: minor changes in spike proteins (HA attachment/NA seperation)

• we predict which vaccine to make each year

Antigenic shifts: major changes as two different viruses infect a host cell, reassortment (mix) of the eight RNA segments can occur —> leads to pandemics

Severe Acute Respiratory Syndrome (SARS)

Respiratory route (droplets)

Caused by coronavirus SARS-CoV-2

sense (+) RNA Virus (high mutation rate) —> production of variants

Cytokine storm is major contributor to severity and mortality

Structure: SME (spike, membrane, envelope)

Diagnosis: ELISA, RT-PCR

Prevention: Vaccination

Respiratory Syncytial Virus (RSV)

Respiratory route

Mostly children

Caused by cell fusion (syncytium) in cell culture

Cold-like symptoms or life-threatening pneumonia

Prevention: RSV vaccine

Mumps

Transmitted in saliva or respiratory 

Targets Parotid glands

Complications in adults: genital inflammation (infertility), pancreatitis 

Prevention: MMR vaccine

Rotavirus

Transmitted via fecal-oral

Causes Viral gastroenteritis

• primarily infants + children

• Symptoms: fever, diarrhea, vomiting

• Prevention: live attenuated oral vaccine

Hepatitis A (HAV)

Fecal-Oral Route

RNA Virus; lacks envelope

Acute infection without carrier state

Has inactivated vaccine

Hepatitis B (HBV) (oncogenic)

Transmitted via blood, bodily fluids, sex

ds-DNA virus (HBV) 

implicated is some cases of liver cancer or liver disease

Prevention: inactivated vaccine

Hepatitis C (HCV)

Transmitted through blood

RNA virus; enveloped

Damages liver, unnoticed “silent epidemic”

No vaccine

Poliomyelitis (Polio)

Transmitted by ingestion of water contaning feces w/ virus (fecal-oral)

Caused by poliovirus

Can cause paralysis

Prevention: Salk vaccine (inactivated vaccine)

Rabies

Transmitted by saliva of animal bite

Caused by rabies virus

RNA virus (mutations)

Virus multiplies in skeletal muscles and through PNS

Symptoms: muscle spasms of mouth and pharynx; hydrophobia, coma, death

Prevention: antibodies

Encephalitis

Caused by mosquitos

Mosquitoes pick up from birds, horses

Prevention: controlling mosquitoes and personal protection

Zika Virus (Teratogenic)

Transmitted via by mosquitoes sex, mother/fetus, blood

Infection during pregnancy greatly increases risk of microcephaly in infancts (mild to severe developmental delays)

Prion

Self-replicating infectious proteins

hard to treat or inactivated 

Must use 

• Scrapie: sheep

• Chronic wasting disease: deer and elk

• Creutzfeldt-Jakob disease: humans

• Variant of CJD: younger humans

• Kuru: human cannibalism

• Bovine spongiform encephalopathy: mad cow disease

West Nile Virus

Transmitted by mosquitoes

Birds are reservoir for the virus

emerging disease, hard to control

Kaposi’s sarcoma

a type of cancer that forms in the lining of blood vessels and lympth vessels caused by Human herpesvirus-8

• HIV increases the risk of this cancer

Norovirus

Transmitted via fecal-oral; aerosolized vomit

Causes viral gastroenteritis 

• All ages

• Most common foodborne illness, very contagious

• Symptoms: diarrhea and vomitting

• Prevention: Hand washing + disinfectant

• Treatment: oral rehydration, no vaccine

Mosquito-borne encephalitis

• Eastern Equine

• Western Equine

• St. Louis Encephalitis