Cardiovascular and lymphatic diseases

Question 1

Malaria characteristics?

Answer 1

dominant protozoan disease
translates to “bad air”
- threatens 40% of worlds population every year

Question 2

Malaria signs and symptoms?

Answer 2

10-16 day incubation period
- highest death rate in acute phase (especially in children)
Symptoms:
- Malaise, fatigue, vague aches, nausea with or without diarrhea, chills, fever, sweating

Complications
- Hemolytic anemia from lysed RBC
- organ enlargement & rupture due to cellular debris accumulating in spleen, liver, and kidneys
- Cerebral malaria = small blood vessels in brain become obstructed due to RBCs adhering to blood vessel walls

Question 3

Malaria causative agent?

Answer 3

Plasmodium spp. (protozoans)
- p. malariae, p. vivax, p. knowlesi, p. ovale, & p. falciparum infect humans

Question 4

Malaria transmission and epidemiology?

Answer 4

Transmission:
primarily spread by female anopheles mosquito
- mosquito control in temperate areas has restricted distribution to a belt around the equator

Epidemiology:
- 90% of cases are reported in Africa w/ most frequent victims being children and young adults
- 1,000-2,000 cases per year in US (mostly from immigrants or travelers to endemic areas)

Question 5

Malaria culture and diagnosis?

Answer 5

definitive diagnosis by discovery of a typical stage of plasmodium in stained blood smears
- newer serological procedures have made diagnosis more accurate are require less skill
- knowledge of the patient’s residence or travel in endemic areas aid in diagnosis
- recurring symptoms of chills, fever, and sweating are also a good indicator

Question 6

Malaria prevention?

Answer 6

long term mosquito abatement and human chemoprophylaxis
- mosquito nets, screens, and repellants
- remaining indoors at night
- taking weekly doses of antimalarial drugs

vaccine development underway in Kenya, Malawi, and Ghana

Question 7

Malaria treatment?

Answer 7

Quinine is standard treatment
- chloroquine is least toxic type and used in nonresistant forms of malaria
protozoan has developed resistance to nearly every drug used in its treatment
- Artemisinin has been most effective (should be used in combination w/ other drugs to prevent resistance development)

Question 8

HIV and AIDS epidemiology?

Answer 8

35 million people have died from AIDS since 1980s
- heterosexual intercourse is primary mode of transportation in most parts of the world
- highest rates among adolescents and young
women
- in US African-Americans have a disproportionate rate of infection (represent 12% of population but 45% of nw diagnoses)

Question 9

HIV causative agent?

Answer 9

Human immunodeficiency virus
- retrovirus
- contains reverse transcriptase which catalyzes the replication of ddDNA from ssRNA
- can permanently integrate viral genes into host genome that is passed to progeny cells

Question 10

HIV signs and symptoms?

Answer 10

spectrum of clinical signs and symptoms dependent on stage of disease

4 stages: initial, Asymptomatic, Chronic asymptomatic, and AIDS
- initial disease: ~2 weeks after infection, fatigue, diarrhea, weight loss, flu like symptoms, and neurological changes
- asymptomatic: Variable in time (months-years) no signs or symptoms, immune cells (CD4+ t cells) being depleted
- Chronic symptomatic: immune system compromised, opportunistic infections occur
- AIDS: Acquired immune deficiency syndrome; CD4 t cells lower than 200; opportunistic infection and cancers common

~1% of people antibody positive for HIV remain free of aids (known as nonprogressors)
- functioning immunity to the virus can develop

Question 11

HIV transmission?

Answer 11

• mainly transmitted through sexual intercourse or transfer of blood or blood products
• infants can be infected via childbirth or breastfeeding

Mode of transmission:
- HIV doesn’t last long outside host & is more sensitive to disinfectants
- not transmitted through saliva
- amniotic fluid, synovial fluid, and spinal fluid, and blood are common ways healthcare workers may be exposed

Question 12

HIV maternal to infant transmission?

Answer 12

treatment of HIV-infected mothers w/ anti-HIV drug has dramatically reduced rate of maternal-to-infant transmission
- untreated mothers pass the virus at a 33% rate

Question 13

HIV culture and diagnosis?

Answer 13

positive test for human immunodeficiency virus
- most viral testing is basted on detection of antibodies specific to the virus in serum or other fluids
- newer tests detect antibodies to the virus and viral antigens simultaneously (Widely used)

false negative results occur when testing is performed before the onset of detectable antibody production
- persons who test negative but were exposed should be tested 3-6 months later

Question 14

HIV prevention methods?

Answer 14

avoidance of sexual contact w/ infected persons
- barrier protection should be used when having intercourse with anyone whose HIV status cannot be proven negative

Avoid intravenous drug use

Pre-exposure prophylaxis (PrEP)

Question 15

HIV treatment?

Answer 15

NO CURE
Combination of 3 drugs from 2 different classes used to treat:
- Treatment should begin soon after diagnosis
- AIDS patients should receive a wide array of drugs to prevent/treat variety of opportunistic infections and other ADIs such as wasting disease

the disease is easily manageable with medication

Question 16

Lyme disease characteristics?

Answer 16

Slow acting but often evolves into a slowly progressive syndrome that mimics neuromuscular and rheumatoid arthritis

Question 17

Lyme disease signs and symptoms?

Answer 17

Initial disease: Erythema migrans (rash)
- bull’s eye rash at the site of tick bite
- appears in ~10% of cases
- can be flat and scaly or pustular
- can mimic appearance of ring worm

other early signs:
- fever, headache, stiff neck, and dizziness

Disseminated disease (if initial phase not treated or treated too late)
- cardiac & neuromuscular symptoms such as facial palsy

chronic/3rd stage:
- crippling arthritis
- some patients have chronic neurological complications

Question 18

Lyme disease causative agent?

Answer 18

Borrelia burgdorferi
- large spirochetes ranging from 0.2-0.5 micrometers in width and 10-20 micrometers in length

Question 19

Lyme disease pathogenesis and virulence factors?

Answer 19

bacterium is a master of immune evasion
-changes surface antigens while in tick and again after it has been transmitted to mammalian host
Provokes strong humoral and cellular immune response
- response mainly ineffective bc of the bacterium’s ability to switch its antigen
- possible that the immune response contributes to the pathology of infection

Question 20

Lyme disease transmission and epidemiology?

Answer 20

Transmission:
Primarily by hard ticks of the genus Ixodes
- Ixodes scapularis

Question 21

Lyme disease transmission and epidemiology?

Answer 21

Transmission:
Primarily by hard ticks of the genus Ixodes
- Ixodes scapularis:
- black-legged deer tick (northeast)
- passes through complex 2-year cycle involving 2
principal hosts
- Ixodes pacificus:
- black-legged tick (California)
- Dusky-footed woodrat (reservoir)

Question 22

Lyme disease diagnosis?

Answer 22

• Diagnosis in the early stages is based on symptoms and history of exposure
• antibody tests are used to diagnose in later stages

Question 23

Lyme disease prevention?

Answer 23

• wearing protective clothing and using insect repellant containing DEET when doing outside activities
  Exposed individuals should:
• check body regularly for ticks
• remove ticks w/out crushing using forceps and gloves (can be infected by tick feces or body fluids)

Question 24

Lyme disease Treatment?

Answer 24

Early prolonged (2-4 weeks) of treatment w/ doxycycline and amoxicillin is effective
- other antibiotics (ceftriaxone and penicillin) used in late lyme disease therapy

Question 25

Rocky Mountain spotted fever (RMSF) epidemiology?

Answer 25

Named for the region it was first detected
- majority of cases concentrated in Southeast and Eastern Seaboard regions
infections occur most frequently in spring and summer (tick vectors most active)

Question 26

RMSF causative agent?

Answer 26

Rockettsia rickettsii
- transmitted by hard ticks (long wood, lone star, and American dog tick)
- American dog tick = most common vector for human transmission