ID - Vector Diseases

lyme disease, rocky mountain spotted fever, zika virus, babesiosis

vector diseases

borrelia burgdorferi

lyme disease etiology

Ixodes scapularis (dammini) - black legged deer tick

lyme disease vector

white footed mouse and other rodents are preferred hosts of immature larvae, white tailed deer preferred host for adult stage

lyme disease epidemiology

increased during june, july, and august

lyme disease incidence

bite from infected tick, questing

lyme disease transmission

how ticks attach

questing

24-36 hours

how long must tick be attached to transmit lyme disease

ankle, groin, popliteal fossa, gluteal folds, axillary folds, earlobe creases, scalp

lyme disease sites of attachment

localized infection, flu-like sx, erythema migrans lesion

stage 1 of lyme disease

3-32 days

lyme disease incubation period

red macule or papule at site of tick bite that lead to large annular lesion, increase in size to form bullseye, warm, not painful

erythema migrans lesion

thigh, groin, and axilla

common site or erythema migrans lesion

extremely erythematous, indurated, vesicular, or necrotic

center of bullseye erythema migrans lesion

disseminated infection, spreads hematogenous to many sites w/in days or weeks after onset of EM, similar skin rash

stage 2

severe headaches, neck stiffness, fever, chills, muscle pain, malaise, fatigue,

stage 2 sx

nervous system, cardiac system, musculoskeletal system

where can disseminated infection affect

bells palsy, meningitis, radiculoneuropathy

neuro manifestations of lymes

carditis, nonspecific ST and T wave changes, doesn't affect vascular lesions or cause pericarditis

cardiac manifestation of lymes

occurs 1-2months after infection, fluctuating degrees of conduction defects, lightheadedness, syncope, dyspnea, palpitation, chest pain

carditis

arthritis, few weeks after onset, monoarticular, sudden sx, improve w/o tx

musculoskeletal manifestations of lymes

chronic, persist inflammation in the nervous system or joints, more than 1 yr, tertiary neuroborreliosis, cognitive disorders, sleep disturbances, fatigue, personality changes, rarely fatal

stage 3

erythema migrans > 5cm in diameter OR 1 disseminated manifestation plus lab confirmation

dx of lymes

serum EIA

labs for lyme disease

no further testing is recommened

if EIA negative

western blot IgG and IgM is performed

if EIA positive

true

t/f both lab test must be positive to confirm lymes

appears 2-4w after onset of early manifestations, peaks at 6-8w, declines after 4-6m

immune serology IgM

appears after 6-8w, peaks 4-6m, remains elevated indefinitely

immune serology IgG

DOC: doxycycline for 10-21 days

alt: amoxicillin for 14-21 days

stage 1 and 2 lyme tx

doxycycline single dose

if treating tick bite w/o signs of lyme

IV meds

late lyme and cardiac involvement tx

false

t/f can use doxycycline when pregnant

doxy based on weight

alt: azithromycin and PCNs

pediatrics lyme tx

north carolina, oklahoma, arkanasas, tennessee, missouri

rocky spotted mountain fever most common states

rickettsia rickettsii

rocky spotted mountain fever etiology

3-12 days after bite, rash

RMSF sx

2-5 days after onset of sx

when does RMSF rash start

petechial rash: small flat pink, non-itchy

early rash of RMSF

starts on wrist, forearms, and ankles and spreads to trunk, palms, and soles

where does RMSF rash appear

involvement of rash on scrotum and vulva

diagnostic clue of RMSF

true

t/f skin necrosis and gangrene can develop in RMSF

clinical, serum antibodies, skin biopsy, basic workup (CBC, BMP, LFTs, coagulation panel)

RMSF dx

doxycycline

RMSF tx

chloramphenicol

RMSF pregnant tx

protective clothing, tick repellent chemicals

RMSF prevention

1-4 days, high fever, severe headache, malaise, myalgia, edema of hands, GI sx

RMSF early signs

5 days and beyond, AMS, ARDS, peripheral necrosis, multiorgan system damage, thrombocytopenia, elevated liver enzymes, hyponatermia

RMSF late sx

mosquito

zika virus vector

sexual contact

zika virus transmission

3-12 days

zika virus incubation period

fever, arthralgia, conjunctivitis, maculopapular rash

mild cases of zika virus

rare, GBS, encephalopathy, myelitis, uveitis, thrombocytopenia

zika virus complications

can cause birth defects or microcephaly and ophthalmologic abnormalities

zika virus pregnancy

NAAT, IgM

zika virus dx

supportive, DEET, abstience

zika virus tx

hemo-protozoan Babesia microti

babesiosis etiology

malaria

what can babesiosis be misdiagnosed as

I. scapularis or blood transfusion

babesiosis transmission

northeast and upper midwest

where is babesiosis primarily found

1-9 weeks after infection, flu-like sx, parasitemia

babesiosis sx

fever, fatigue, headache, arthralgia, myalgia, nausea, vomiting, thrombocytopenia, anemia, splenomegaly

flu-like sx

elderly and immunocompromised

in what pts does babesiosis cause severe complications

respiratory failure, severe hemolytic anemia, renal failure, CHF

babesiosis complications

thick and thin blood smears stained w Giemsa, PCR testing

babesiosis dx

atovaquone and azithromycin for 7d-6w

babesiosis tx

clindamycin and quinine

babesiosis tx alt