Global Infectious Disease

Question 1

Describe the etiology/RF for Malaria

Answer 1

Anopheles mosquito transmitting 4 types of plasmodium (p. Falciparum MC)

High risk: infants, kids <5, pregnant, HIV/AIDs, non-immune migrants, mobile populations/travelers

Disease burden in the African continent

Question 2

Describe the clinical presentation of the most common plasmodium of malaria

Answer 2

P. Falciparum:
- Incubation period: 7-10 days, clinically apparent 1+ month after exposure
- sxs: Quotidien cyclical fever, anemia, splenomegaly, jaundice, flu-like, n/v/d,
- progression: to malignant tertian/fulminant dz, parasitized RBCs adhere to vasculature leading to infarcts & circulatory collapse, to cerebral malaria: AMS, seizure, edema, retinopathy, renal failure, hemoglobinuria, metabolic acidosis

Question 3

Describe the diagnostic testing for malaria

Answer 3

Parasitemia, anemia, thrombocytopenia, elevated transaminases, mild coagulopathy, elevated BUN and serum Cr

+/- rapid detection tests

Question 4

Describe the treatment of malaria

Answer 4

Hosp: young children, immunocompromised, no acquired immunity, hyperparasitemia

Artemisinin combo therapy: artemether-lumefantrine (first line),

Other antimalarials: atovaquone-proguanil, doxy + v quinine, tetracycline + quinine, clinda + quinine, hydroxy/chloroquine

If prophylaxis was used, treat with a different drug

Question 5

Describe the etiology of Dengue

Answer 5

Aedes aegypti mosquito

Disease burden in asia, urban tropical areas

Question 6

Describe the clinical presentation of dengue

Answer 6

Flu-like

Febrile phase
- high fever plus 2+ of the following sxs: severe HA, pain behind eyes, myalgia/arthralgia, n/v, LAD, rash

Critical phase
- Fever wanes, sever abd pain, persistent vomiting, tachypnea, bleeding gums/nose, fatigue, restless, liver enlargement, blood in vomit/stool

Severe dengue
- Severe plasma leakage, respiratory distress, hemorrhage, organ impairment

Convalescent phase
- Plasma leakage & hemorrhage resolves, vitals stabilize, fluids resorbed, secondary rash appears

Question 7

Describe the diagnostic testing for dengue

Answer 7

Positive tourniquet test, leukopenia, hemorrhagic manifestations, AST/ALT >1000

Blood serology

Question 8

Describe the treatment for dengue

Answer 8

Supportive care: hydration, avoid ASA and NSAIDs, treat fever with APAP & tepid sponge bath

Question 9

Describe the etiology of zika

Answer 9

Aedes species mosquito (day & night)

Vertical transmission, blood transfusion

Question 10

Describe the clinical presentation of zika

Answer 10

Asymptomatic/mild sxs: fever, rash, HA, arthralgia, red eye, myalgia for a few days/weeks

Danger to fetus: microencephaly, brain defects, miscarriage, still birth, defects (+/- guillain barre)

Question 11

Describe the diagnostic testing for zika

Answer 11

Trioplex real time PCR assay, Zika MAC-ELISA

History based on travel

Question 12

Describe the etiology of trachoma

Answer 12

Chlamydia trachomatis transmitted by flies

Transmission via contact, fomites, flies from eye discharge

Disease burden in rural Africa, central/south America, Asia, Australia, Middle East

Question 13

Describe the clinical presentation of trachoma

Answer 13

Keratoconjunctivitis leading to ocular morbidity

Often begins in infancy/childhood, recurrent/reinfection causes chronic follicular conjunctival inflammation/scarring, leads to irreversible blindness

Question 14

Describe the treatment for trachoma

Answer 14

Surgery, antimicrobials, facial cleanliness, environmental change (SAFE)

Question 15

Describe the etiology of chagas

Answer 15

American trypanosomiasis (protozoan parasite Trypanosoma cruzi)

Transmitted to humans & mammals by contact with feces/urine of vector-borne triatomine (food, blood transfusion, organ transplant, lab accidents)

Disease burden in Latin America

Question 16

Describe the clinical presentation of chagas

Answer 16

Acute
- Incubation of vector borne: 7-14 days
- 2 mos: skin lesion, purplish swelling of lids of one eye (chagoma/romana sign), fever, malaise, anorexia, edema, rash
- Acute manifestations resolve 3-8 weeks

Intermediate
- No sxs, diagnosed thru blood-donor screening or serologic testing

Chronic
- cardiac arrhythmias, CHF, cardiomyopathy, thromboembolisms, megaesophagus, megacolon, gastric dilation, hepatosplenomegaly

Question 17

Describe the treatment for chagas

Answer 17

Screening of newborns & siblings of infected moms without antiparasitic treatment

Benznidazole, nifurtimox

Manage sxs

Question 18

Describe the etiology of leprosy

Answer 18

Chronic infection caused by mycobacterium leprae (aka hansen disease)

Vigorous cellular immune response: tuberculoid form

Minimal cellular immune response: lepromatous form

Armadillos are major reservoir for S. US

Question 19

Describe the clinical presentation of leprosy

Answer 19

Tuberculoid
- strong Th1 cell-mediated response, low infectivity, skin & peripheral nerve involvement, skin lesions, asymmetric neuropathy

Lepromatous
- Th2/IgG mediated humoral response, high infectivity, extensive skin involvement (nodules, plaques, spares groin/axilla/scalp), symmetric neuropathy

Question 20

Describe the diagnostic testing for leprosy

Answer 20

Ag skin test positive in tuberculoid type & negative in lepromatous type

Skin smear positive for acid-fast bacilli

Question 21

Describe the treatment for leprosy

Answer 21

Focus on preventing disability & transmission, OT to modify environment

Tuberculoid: Dapsone + rifampin 6 mos

Lepromatous: Dapsone + rifampin + clofazimine 2-5 years

Monitoring: CBC, Cr, Liver pane

Question 22

Describe the etiology of ebola

Answer 22

Primary exposure: travel
Secondary exposure: human contact, primate contact, bush meat for consumption

Disease burden in Southern & Western Africa

Question 23

Describe the clinical presentation of ebola

Answer 23

Early
- fever, pharyngitis, severe constitutional sx, maculopapular rash, bilateral conjunctival injection

Late
- expressionless facies, bleeding from IV sites & mucous membranes, myocarditis & pulm edema, tachypnea, hypotension, anuria, coma

Question 24

Describe the diagnostic testing for ebola

Answer 24

Blood testing, CBC, liver/kidney function, isolating the virus, serologic testing

Question 25

Describe the treatment for ebola

Answer 25

Supportive therapy (IV volume, electrolytes, nutrition, comfort), barrier isolation

Recovery: months long, slow return of weight & strength, 50% average fatality