Class 4 Flashcards
What are viral infections/virus?
• Viruses are smallest obligate intracellular pathogen.
• no organized cellular structure.
• consist of protein coat (a.k.a. capsid) surrounding
nucleic acid core of RNA or DNA.
• some enclosed within lipoprotein envelope derived from cytoplasmic membrane
of parasitized host cell.
How do viruses work?
• viruses incapable of replication outside a living cell
• virus will attach to host cell, enter it, then release its genetic material
• replicates immediately or can remain dormant for extended period of time
• host cell usually dies then virus can release viral replications, which can go on to infect other cells
What are routes of viral infection?
• Nasal & respiratory
• Oral & gastrointestinal
• Through blood & bodily fluids (needles, bites, STI’s)
What is the body’s response to viral infections?
• Inflammatory response – vascular congestion & leakage
of exudate
• Immune response – collection of lymphocytes in infected tissue
-Medical treatment is supportive, may involve use of
anti-viral drugs
-Prevention is by IMMUNIZATION
What is Inflammatory response to viral infections?
vascular congestion & leakage of exudate
What is Immune response to viral infections?
collection of lymphocytes in infected tissue
What is Poliomyelitis?
• acute viral infection, can affect nervous system.
• may lead to full or partial paralysis.
• caused by poliovirus
• 2 types: paralytic & non-paralytic
• highly contagious, can spread by contact with infected mucous, phlegm or feces through mouth & nose.
• multiplication occurs in lymphoid tissue of throat & GI tract then invasion of CNS.
• incubation period is 5-35 days.
• can be prevented with immunization.
What is Rubeola (Measles)?
• highly contagious respiratory infection
• caused by paramyxovirus
• causes total body skin rash with flu like symptoms (fever, cough, & runny nose)
• treatment is palliative
• prevented with immunization
What are the 2 types of Poliomyelitis?
• paralytic - more severe (full paralysis)
• non-paralytic - flu like symptoms (partial paralysis)
What is Rubella (German Measles)?
• caused by rubella virus
• primarily affects skin & lymph nodes
• spread by inhaling infected droplets
• can pass through placenta from mother to
fetus, lead to CONGENITAL RUBELLA SYNDROME which may lead to visual & hearing impairments, heart disease, spleen, liver, bone marrow abnormalities, & thrombocytic purpura (BLUEBERRY MUFFIN RASH)
• symptoms include fever, headache, general malaise, runny nose, skin rash are more severe in adults than children
• infection results in lifelong immunity
• prevented with immunization
What is mumps?
• highly contagious viral infection, spread through saliva.
• primarily affects parotid glands.
• S/S fever, headache, arthralgia, loss of appetite, followed by pain & swelling of parotid glands.
• uncommon under 12 months old
• first infection will yield lifelong immunity
• treatment aimed at reducing pain
What is Chicken Pox?
• common, preventable childhood infection caused by Varicella-Zoster virus.
• usually mild, but uncomfortable in children & more severe in adults.
• spreads by direct contact & droplet transmission
• can spread to fetus from infected mother
• S/S fever, followed by itchy rash changes to fluid filled blisters which break & scab
• most cases result in lifelong immunity
• prevented with immunization
What is Shingles aka zona aka Herpes-Zoster?
• not a childhood illness
• only occurs in people who have had chicken pox
• remains dormant in dorsal root ganglia for years
• usually activated by stress.
• less contagious, does not spread through droplet transmission
• leads to acute CNS infection involving primarily
DRG.
• S/S include neuralgic pain & vesicle eruption on
skin which resembles chicken pox but presents in dermatomal pattern consistent with DRG in which virus was dormant.
• if you’re susceptible to Chicken Pox (meaning you are not immune/did not get vaccine) you can catch Chicken Pox from Shingles BUT YOU CAN’T catch Shingles from Shingles
What is the Common Cold?
• mild infection of upper respiratory tract.
•caused by several different viruses including rhinovirus, adenovirus & coronavirus.
• S/S are sneezing, stuffy nose, sore throat, coughing
• lasts between 2-14 days
• highly contagious, can spread by droplets. sneezing/coughing by direct or indirect contact.
What is Influenza (The Flu)?
• viral infection of lower respiratory tract
• mild or life threatening
• 3 types of influenza virus – A, B, & C & are further sub-categorized based on
2 surface antigens: hemagglutinin & neuraminidase (DW). Ex. of Types A Influenza include H1N1, H5N1, & H3N2.
• occurs every 2-3 years in epidemics.
• high mortality rate among elderly
• S/S are chills, fevers, headache, arthralgia, sore throat, cough
• can lead to life threatening complications & secondary infections like pneumonia
• spread in same manner as common cold
• influenza virus is constantly mutating, giving rise to different
antigen presentations.
What is SARS?
• Severe acute respiratory syndrome (SARS) illness caused
by new form of coronavirus. Thought to have originated in civets (type of cat) in China. spread by close person to person contact
• S/S initially presents with cold like symptoms, high fever is
key diagnostic sign then spreads to lower respiratory tract
causing pneumonia that’s fatal in 10% of cases
• Treatment is palliative with special attention to reduction of
fever
• No vaccines or specific medications available; O2 supplied as
needed
What is MERS?
• Middle East respiratory syndrome (MERS) is new SARS like
virus.
What is Intestinal Flu (viral enteritis, gastroenteritis – Con Al – while names are similar, this is not same as influenza)?
• most common type of gastrointestinal infection
• spread through contaminated food or water & dreaded
fecal oral route.
• more common in children
• lasts 1-2 days (sometimes called 24-hour flu)
• S/S are nausea, vomiting, diarrhea, malaise, low grade fever,
abdominal pain
• treatment is palliative
There are 2 types of herpes infections. What is Type 1?
• causes oral & skin lesions on or near lips called “cold sores” or “fever blisters”
• after initial infection, virus stays dormant in nerve cells
• flare ups are precipitated by stress or febrile illness
• transmitted by direct contact
• can cause encephalitis
There are 2 types of herpes infections. What is Type 2?
• causes genital infection
• stays dormant in nerve cells after initial infection
• may be transmitted during childbirth
• can produce fatal disseminating neonatal infection
What is Human Papilloma Virus (HPV)?
• more than 100 types of HPV, most are harmless & just cause warts (verrucae).
• only 30 types give risk of cancer, these types usually affect
genitals & spread through sexual contact
• warts cause proliferative lesions of squamous epithelium.
• associated with increased risk of developing cervical cancer & in recent years there has been an increase in oral & pharyngeal cancers in men.
•’there is preventable vaccine
What is Mononucleosis (the kissing disease)?
• caused by Epstein-Bar virus.
• saliva is primary method of transmission can also be spread by coughing, sneezing or sharing infected eating utensils/drinking glasses
• incubation period is 4-6 weeks
• S/S fever, sore throat, generalized lymphadenopathy,
lethargy, splenomegaly, hepatitis, & atypical lymphocytes.
• lasts for weeks sometimes months to years.
• more common amongst teenagers & young adults
• virus remains in body, can become active without symptoms later in life
What is Human Immunodeficiency Virus (HIV)?
• virus leads to Acquired Immune Deficiency Syndrome (AIDS).
• spread by contact with infected bodily fluids (blood/semen)
• first presents with mild flu like symptoms then lies dormant for years
• when it reactivates, it attacks T-cells
• as T-cells die, immune system looses ability to defend body against infection
• death was due to pneumonia or other opportunistic infections
• now medications that have made HIV no longer a
death sentence
What is Viral Hepatitis?
-diffuse inflammatory disease of liver.
-caused by several different viruses
-S/S are nausea, vomiting, malaise, fever, headache, dark urine,
jaundice, enlarged liver, excess bruising, and pain in abdomen.
What is Hep A?
• Caused by enterovirus
• acute infection – no chronic stage, is not progressive, does not cause permanent liver damage
• spread by contaminated food/water
• occurs sporadically or in epidemics
• incubation roughly 30 days
• immune system makes antibodies that confer immunity to
future infection
• prophylaxis through immunization
What is Hep B?
• more serious health problem – has chronic stage/carrier state.
• 2-6 month incubation period
• spread by contaminated feces, bodily fluids including
saliva, contaminated breaks in skin, sex or contaminated tissue transplant
• Prophylaxis through immunization
• can lead to cirrhosis
What is Hep C?
• serious disease – often becomes chronic, leads to cirrhosis of liver & liver cancer
• incubation period 2 weeks to 6 months
• spread similar to Hep B
What is Hep D?
• only present with Hep B infection
• severe & sudden type of hepatitis & liver cirrhosis are
more common with Hep D than Hep B infection
What is Hep E?
• clinically resembles Hep A – no chronic stage
• transmitted by fecal oral route
What are SEXUALLY TRANSMITTED INFECTIONS (STI)
• infectious condition spread through sexual contact.
• agents of infection include: bacteria, viruses, chlamydia fungi,
protozoa, & parasites
• portals of entry: genitals, mouth, urinary meatus, rectum, skin
• rates are highest among adolescents, but any sexually active
person may contract one, are higher with people who have more than one sex partner.
• incidence: increasing + still unreported cases
• sexual hygiene is important to control spread
• testing is important to stay informed & control/prevent
spread
What is Condylomata Acuminata (Genital Warts)?
• caused by Human Papilloma Virus (HPV)
• most of time asymptomatic & resolve on their own
• may lead to cervical cancer, there is possible link to oropharyngeal cancers
• there is currently a vaccine to prevent HPV infection
What is Candidiasis (Yeast Infection, Thrush)?
• not strictly an STI
• can also occur in GI tract or mouth & throat
• Candida Albicans is most common yeast to cause infection
• common vaginal infection
• men may have candida on their penis but usually asymptomatic
• causes vaginal pruritis, erythema, swelling, dysuria, &
dyspareunia
• typical vaginal discharge is usually thick, white, & odorless
• treated with antifungal medications
What is Trichomoniasis?
• caused by anaerobic protozoa
• more common than Gonorrhea
• often considered marker for high risk sexual behavior
• protozoa can live in paraurethral glands of both sexes
• >75% of women women develop symptoms, men usually asymptomatic
• s/s: copious, frothy, malodorous, green or yellow discharge
• small hemorrhagic areas may appear on cervix – known as “strawberry spots”
• may lead to tubal infertility in women & atypical pelvic inflammatory disease
• can lead to infertility, altered sperm motility, & chronic prostatitis in men
• treated with systemic antiprotozoan medications
What is Chlamydia Infection?
• one of most common STIs in North America
• S/S for women:mucopurulent cervical discharge, urinary frequency, & dysuria. Hypertrophy of cervix + becomes erythematous, edematous, & extremely friable, may lead to fallopian tube damage. If left untreated may lead to PID.
• S/S for men include urethritis, meatal tenderness & rubor, urethral pruritis, discharge, & dysuria. Prostatitis & epididymitis may develop/lead to infertility if left untreated may lead to Reiter syndrome – reactive arthritis that leads to conjunctivitis, urethritis, & mucocutaneous lesions
• since high numbers of people are asymptomatic, there are many cases that go untreated
• regular screening is important
• may be treated with antibiotics
What is Gonorrhea?
• caused by Nisseria Gonorrhea bacteria
• ages 15-44 most common + women>men
• rising incidence
• usually spread through intercourse (vaginal/anal)
• babies born to infected mothers are at risk of contracting gonorrheal conjunctivitis which may lead to permanent blindness.
• in men, infection starts in anterior urethra, may spread proximally in genital tract. S/s: urethral pain, dysuria, creamy yellow or blood urethral discharge. May become chronic & infect epididymis, & prostate.
• in women, s/s: unusual vaginal discharge, dysuria dyspareunia, pelvic pain, proctitis, fever. Chronic infections may lead to salpingitis with subsequent scarring & infertility.
• in both men & women it may invade circulatory system & cause sequelae in joint spaces, heart valves, meninges, & other tissues of the body.
• many cases are asymptomatic which may lead to further spreading of infection
• currently considered to be resistant to all know antibiotics
What is Syphilis?
-caused by Treponema pallidum bacteria
-incidence has been increasing
-has three stages, Primary, Secondary & Tertiary.
What is the Primary Stage of Syphilis?
• characterized by lesion on site of sexual contact.
- starts as button like papule called chancre that erodes to become clean ulceration on an elevated base.
- apparent between 1 week-3 months after exposure but usually in first 3 weeks.
• lesion is generally more obvious on men, so it may go untreated in women. Chancre usually heals in 3 to 12 weeks even without treatment.
What is the Secondary Stage of Syphilis?
• timing of stage varies greatly.
• S/S: maculopapular rash, especially on palmer+plantar surfaces of hands+feet respectively, fever, sore throat, nausea, anorexia, & conjunctivitis.
• may develop Alopecia and/or Condylomata Lata.
• Infection enters latency period + infected persons are still contagious for up to two years or for life, or may develop into tertiary syphilis.
What is the Tertiary Stage of Syphilis?
• may develop as long as 20 years after initial infection.
• only 1 in 3 untreated cases will develop tertiary stage.
• Lesions may include:
- Destructive lesions called Gumma–rubbery, non inflammatory,
necrotic lesions commonly found on the liver testes, or bone.
- Cardiovascular (CV) lesions – usually cause scarring of
medial layer or thoracic aorta with aneurysm formation. Aneurysm may lead to aortic valve insufficiency, & CHF.
• CNS lesions – may lead to dementia, blindness, spinal cord injury, ataxia, & sensory loss.
• Treatment is with antibiotics, may have to be continued for several weeks.
• Pregnant women infected with syphilis may experience premature or still birth. Baby may be born with congenital defects or an active infection.
