chapter 21 diseases Flashcards
what causes Lyme disease?
Borrelia burgodorferi
what causes mono?
Epstein-Barr virus
what causes malaria?
Plasmodium
characteristics of Lyme disease?
Gram-negative spirochete that has Endo flagella within the periplasmic space
Burrows into tissues
characteristics of mono?
Enveloped ds DNA virus
characteristics of malaria?
has 3 life cycles
reservoir of Lyme disease?
White-footed mouse; chipmunks, short-tailed and masked shrews, and eastern gray squirrels
reservoir of mono?
Humans
reservoir of malaria?
Humans
mode of transmission for Lyme disease?
Biological vector; Hard ticks of the genus lxodes
(NYMPHS and adults responsible for transmission)
mode of transmission for mono?
saliva (direct or indirect)
mode of transmission for malaria?
biological vector; Mosquito bite
portal of entry for Lyme disease?
bite of a tick
portal of entry for mono?
mouth
portal of entry for malaria?
bite of a mosquito
virulence factors of Lyme disease?
Lacks iron-containing enzymes and molecules
Changes outer surface proteins
Symptoms mimic many other diseases
virulence factors of mono?
Becomes latent within cells, resulting in lifelong infection. Causes B lymphocytes to become immortal which then are one source of cancer
virulence factors of malaria?
-reproductive cycle occurs within RBC
-genetic and antigenic variation
-adhesins
-it can change the attractiveness of their vertebrate hosts to anopheles vector
how does Lyme disease affect the body?
Infection occurs within 12-24 hours after a bite of a tick.
Organisms move from the site of infection through the blood and lymph
Can accumulate in joints.
Can remain dormant
how does mono affect the body?
Infects the epithelial cells of the throat and parotid salivary glands. Lytic replication cycle releases virions into the bloodstream.
Virus then invades B lymphocytes which then spread the infection throughout the body
how does malaria affect the body?
complex life cycle
signs and symptoms of Lyme disease?
Mimics other diseases
1. Early phase: expanding red rash resembling bull’s eyes; malaise, headache, dizzy, stiff neck, fatigue, chills, muscle and joint pain, infected lymph nodes.
2. Disseminated: secondary ringed rashes, flu, arthritis, heart arrythmia, myocarditis, pericarditis, bell’s palsy, meningitis
3. Chronic: severe fatigue, sleep impairment, joint pain, depression, headaches
signs and symptoms of mono?
CTLs kill infected B cells (responsible for signs and symptoms)
-4 to 6 weeks after infection
-severe sore throat, fever, and weakness
-swollen lymph nodes in neck and armpits, enlarged spleen, extreme fatigue, nausea, loss of appetite, headache, and skin rash
signs and symptoms of malaria?
can be asymptomatic
-uncomplicated: fever, moderate to severe shaking chills, sweating, headache, n/v, diarrhea, and anemia
-severe: anemia, organ damage, coma, pulmonary complications, and AKI
epidemiology of Lyme disease?
discovered in 1975 in wooded areas
coyotes removed the foxes that eat the mice
epidemiology of mono?
In children, <6 EBV causes a mild illness that resembles common respiratory infections.
Where living standard are higher, childhood infection is less likely and infection does.
Not occur until adolescence or later
epidemiology of malaria?
-humans are the reservoir for human malaria
-endemic in 109 countries
-temperature, humidity, rainfall
diagnosis for Lyme disease?
Based on the signs and symptoms or the disease and the history of exposure to ticks
-antibodies against borrelia (neg. test does not mean pt. does not have lyme. Takes >4-6)
diagnosis for mono?
based on the presence of large, lobed B lymphocytes with atypical nuclei and neutropenia
-Can test for antibodies to
-viral capsid antigen
-early antigen
-EBV nuclear antigen
diagnosis for malaria?
Can be easily identified and distinguished in blood smears so microscopy is commonly used.
Demonstration of antibodies against plasmodium can be used for differential diagnosis.
-case history, including travel history, vital
treatment for Lyme disease?
Antimicrobial drugs such as doxycycline or amoxicillin, or cefuroxime axetil can cure if disease in the first phase.
-prolonged tx with large doses may be required
-iv drugs may be required
treatment for mono?
Care involves relief of the symptoms.
-most recover without treatment within 2-4 weeks
-avoid contact sports to reduce risk of rupturing enlarged spleen
treatment for malaria?
-Tx varies by species
-drug choices are constantly revised based on effectiveness and existence of resistant strains
prevention of Lyme disease?
Prevent contact with ticks in the summer when nymphs are feeding.
-wear long-sleeved shirts and ling, tight fitting pants
Use DEET
-examine body for ticks
Remove ticks using forceps
prevention of mono?
No vaccine
EBV may persist in saliva for months following infection.
Prevention almost impossible
prevention of malaria?
Limit contact with mosquitoes
Drain wetlands from standing water
DEET
Prophylactic drug
