N236: Viral Infections of Humans

Chickenpox pathogen

Varicella zoster virus

Chickenpox (Varicella) mode of transmission

Direct contact, or inhaling aerosols from vesicular fluid

Chickenpox (Varicella) S+S

Fever, malaise, rash on chest that spreads to limbs, macular --> papular --> vesicular --> crust

Chickenpox (Varicella) prevention

Varicella vaccine

Dose 1 at 12-15 months, dose 2 at 4-6 yrs

Shingles (Herpes Zoster) pathogen

Varicella zoster virus

Shingles (Herpes Zoster) S+S

Tingling/burning/stinging → one sided vesicular rash on neck or chest, pain can persist for months-years after rash clears (post herpetic neuralgia)

Shingles (Herpes Zoster) prevention

Shingrix vaccine

2 doses 2-6 mos apart in people > 50 yo

Shingles (Herpes Zoster) recurrence

Latent lives in the dorsal root ganglia neurons of the cervical/thoracic spinal nerves

Smallpox pathogen

Variola virus

Smallpox (Variola) S+S

High fever, exhaustion, widespread rash that leaves permanent scars (macular --> papules --> vesicles --> crust)

Smallpox (Variola) transmission

Direct contact, inhalation of vesicular secretions

Measles pathogen

Rubeola virus

Measles (Rubeola) S+S

Fever, runny nose, cough, conjunctivitis, photosensitivity, Koplik spots in the mouth, skin rash on the face that spreads

Measles (Rubeola) transmission

Inhalation or contact w/ oropharyngeal or respiratory secretions

Measles (Rubeola) prevention

MMR vaccine (measles, mumps, and rubella)

Doses at 12-15 months and 4-6 years

German Measles pathogen

Rubella virus

German Measles (Rubella) S+S

Mild fever, malaise, followed by maculopapular skin rash (face → body), milder than measles, resolves in 3 days

Congenital rubella syndrome

A birth defect that occurs when the mother becomes infected with the rubella virus in her first trimester

Hearing loss, heart defects, eye anomalies

German Measles (Rubella) transmission

Inhalation or contact w/ oropharyngeal or respiratory secretions

German Measles (Rubella) prevention

MMR vaccine

Doses at 12-15 months and 4-6 years

Acute Viral Rhinitis pathogen

160 types of rhinovirus

Acute Viral Rhinitis S+S

Malaise, inflammation of mucous membranes of URT (common cold symptoms)

Acute Viral Rhinitis transmission

Inhalation or contact with infected respiratory and oropharyngeal secretions

Acute Viral Rhinitis prevention

Handwashing, avoid people who are sick

Croup pathogen

Parainfluenza virus

Croup alternate names

Laryngotracheitis, Laryngotracheobronchitis

Croup S+S

Begins as common cold, then within 24 hours, airways narrow and cause barking cough and stridor

Croup transmission

Inhalation or contact with infected respiratory and oropharyngeal secretions

Croup prevention

Handwashing, no vaccine

Influenza (Flu) pathogen

Influenza viruses A, B, and C

Influenza (Flu) S+S

High fever, chills, dry cough, nasal congestion, aches and pains, pneumonia = serious complication

Influenza (Flu) transmission

Inhalation or contact with infected respiratory and oropharyngeal secretions

Influenza (Flu) prevention

Annual flu vaccine

What do H and N stand for?

Hemagglutinin and Neuraminidase; different surface proteins of influenza viruses

Cute n fun vid:

https://www.youtube.com/watch?v=Z2Y0GMCFWq0&feature=share&si=ELPmzJkDCLju2KnD5oyZMQ

Bird Flu pathogen

Avian influenza virus

Avian Influenza (Bird Flu) S+S

High fever, chills, dry cough, nasal congestion, aches and pains, pneumonia = serious complication

Avian Influenza (Bird Flu) Reservoir

Infected wild and domesticated birds

Avian Influenza (Bird Flu) transmission

Contact with infected poultry or surfaces with excretions from infected birds

Hantavirus Pulmonary Syndrome pathogen

Hantavirus

Hantavirus Pulmonary Syndrome S+S

High fever, chills, headache, fatigue, hypotension, myalgia, SOB due to fluid in alveoli

"tight band around chest" or "pillow over face"

Hantavirus Pulmonary Syndrome Reservoirs

Infected rodents (deer mice, rice rats)

Hantavirus Pulmonary Syndrome transmission

Inhalation of rodent feces, urine, or saliva

Hantavirus Pulmonary Syndrome prevention

Stay AWAY from the rats

Coronavirus Infections

SARS-CoV, MERS-CoV, SARS-CoV-2

ranging from upper respiratory infection to bronchitis progressing to SARDS

SARS-CoV

Severe acute respiratory syndrome; Coronavirus

MERS-CoV

Middle East Respiratory Syndrome; Coronavirus

SARS-CoV-2

Coronavirus Disease 2019

Coronavirus S+S

Fever, chills, cough, fatigue, headache, myalgia, malaise

Coronavirus Reservoirs

Bats (for SARS-CoV and SARS-CoV-2) camels (for MERS-CoV)

Coronavirus transmission

Contact or inhalation of respiratory secretions

Herpes Labialis pathogen

Herpes simplex virus (usually type 1)

Herpes Labialis S+S

Burning pain, vesicles form around lips, blisters break, crust, and heal, no scarring

Herpes Labialis transmission

Direct contact with vesicle or vesicular fluid

Herpes Labialis prevention

Handwashing, avoiding kissing or oral sex during an active outbreak, no vaccine

Herpes Labialis reoccurrence

Virus lives in the sensory neurons of the trigeminal (5th cranial nerve) ganglion (which relays sensory information from the face and head to the CNS)

Viral Gastroenteritis (Stomach Flu) pathogen

Rotavirus, norovirus, adenovirus

Viral Gastroenteritis (Stomach Flu) S+S

Nausea, vomiting, abdominal pain, dysentery, severe dehydration, fever; self-limiting lasting ≈ 48 hours

Viral Gastroenteritis (Stomach Flu) transmission

Fecal-oral route, from infected humans or shellfish

Viral Gastroenteritis (Stomach Flu) prevention

Handwashing, disinfecting surfaces (especially in the bathroom and kitchen), rotavirus vaccine

Viral Hepatitis pathogens

Hepatitis A virus (HAV)

Hepatitis B virus (HBV)

Hepatitis C virus (HCV)

Hepatitis D virus (HDV)

Hepatitis E virus (HEV)

Acute viral hepatitis

HAV and HEV

Pre-icterus phase

Myalgia, arthralgia, fatigue, loss of appetite, nausea, vomiting, abdominal pain, elevated ALT and AST

Icterus phase

Abdominal pain, increased serum bilirubin

Convalescent phase

Increased sense of well-being, return of appetite, disappearance of jaundice

Chronic viral hepatitis

HBV, HCV, and HDV

Hepatitis A

Pathogen: HAV

Transmission: Fecal-oral route

Prognosis: Benign and self-limiting, does not cause chronic hepatitis or induce a carrier state

Prevention: HAV vaccine

Hepatitis B

Pathogen: HBV

Transmission: Unprotected sex, injected drug use

Prognosis: Serious, can cause chronic hepatitis or induce a carrier state

Prevention: HBV vaccine

Hepatitis C

Pathogen: HCV

Transmission: injection drug use

Prognosis: Serious, can cause chronic hepatitis or induce a carrier state

Prevention: NO VACCINE

Hepatitis D

Pathogen: HDV

Transmission: Requires the presence of HBV for its replication, so it can only cause an infection in people who have an HBV infection

Prognosis: Serious, can cause chronic hepatitis or induce a carrier state

Prevention: HBV vaccine

Hepatitis E

Pathogen: HEV

Transmission: Fecal-oral route

Prognosis: Benign and self-limiting, does not cause chronic hepatitis or induce a carrier state

Prevention: HEV vaccine

Herpes Genitalis (anogenital herpes) pathogen

Herpes simplex virus (usually type 2)

Herpes Genitalis S+S

Itching, then vesicular eruptions that break and crust, cause scarring

Herpes Genitalis transmission

Sexual contact (w/ infected secretions)

Herpes Genitalis prevention

Use condoms

Herpes Genitalis recurrence

Virus lives in the dorsal root ganglion of the sacral spinal nerves

Condyloma Acuminatum pathogen

Human papillomavirus (>200 types)

Condyloma Acuminatum S+S

Genital warts: rapid growing, tiny, moist, pink/red, may become cauliflower like

Condyloma Acuminatum transmission

Sexual contact

Condyloma Acuminatum prevention

HPV vaccine

2 doses usually given 11-12 years

HIV Infection & AIDS pathogen

Human immunodeficiency viruses (types 1 and 2)

Acute HIV Infection

Flu-like symptoms that appear 2 weeks after contraction of virus

Chronic HIV infection

No specific S+S (can last 10 years or longer)

AIDS

Fatigue, recurrent fever, chronic diarrhea, weight loss, rashes

CD4+ helper T cell count < 200 cells per mm3 of blood

Candida albicans infection

HIV opportunistic infection --> causing yeast infection in the mouth, thrush

Human herpesvirus 8 infection

HIV opportunistic infection --> affects the endothelial lining of small blood vessels (resulting in Kaposi sarcoma)

Mycobacterium tuberculosis infection

HIV opportunistic infection --> Bacterium that can affect the lungs (resulting in pulmonary tuberculosis)

HIV Infection & AIDS transmission

Sexual contact, blood contact, mother-to-baby

Pre-exposure prophylaxis (PrEP)

Pill containing antiviral drugs that is taken before exposure to HIV to prevent infection

Post-exposure prophylaxis (PEP)

Antiviral drugs used after possible HIV exposure

Treatment as prevention (TasP)

The use of antiretroviral therapy among infected individuals to decrease their risk of transmitting HIV to their partners

Infectious Parotitis pathogen

Mumps virus

Infectious Parotitis (Mumps) S+S

Fever, poor appetite, fever, myalgia, malaise → painful swelling of parotid glands

Complications: oophoritis, orchitis

Infectious Parotitis (Mumps) transmission

Inhalation or contact with oropharyngeal secretions

Infectious Parotitis (Mumps) prevention

MMR Vaccine

Viral Hemorrhagic Fevers pathogens

1. Ebola virus

2. Marburg virus

3. Dengue virus

4. Zika virus

5. Yellow fever virus

Viral Hemorrhagic Fevers S+S

High fever, fatigue, dizziness, myalgia, arthralgia, bleeding under the skin, in internal organs, or from facial cavities

Viral Hemorrhagic Fevers transmission

Ebola/Marburg: body fluid contact

Zika/Dengue/Yellow fever: Aedes mosquito bite

Viral Meningitis pathogen

Several types of viruses

Viral Meningitis S+S

Fever, headache, nuchal rigidity, altered mental status (aseptic meningitis)

Viral Meningitis transmission

Varies depending upon the type of virus