Vector-borne

Question 1

Which rodents are associated with plague?

Answer 1

Mastomys natalensis
Rattus rattus (black rat)

Question 2

What treatment can be given to people associated with patients infected with plague?

Answer 2

Bactrim
Doxycycline

Question 3

What are the forms of plague?

Answer 3

Bubonic
Pneumonic
Carbuncular
Can causes sepsis (enterobacter - gram negative sepsis)

Question 4

What type of bacteria is yersinia pestis?

Answer 4

Obligate intracellular

Question 5

What are the 3 major filarial infections?

Answer 5

Lymphatic filariasis
Onchocerciasis
Loiasis

Question 6

Which organism causes lymphatic filariasis?

Answer 6

W. bancrofti

Question 7

Which organism causes onchocerciasis?

Answer 7

O. volvulus

Question 8

Which organism causes loiasis?

Answer 8

Loa loa

Question 9

What is the life cycle of filaria?

Answer 9

Vector feeds on human host and transmits larval stage -> adult worms develop in host tissue and mate -> microfilariae produced -> vectors ingest the microfilariae -> larval stage develops in the vector

Cannot have more adult worms without repeated bites!

Question 10

Where do adult worms live in lymphatic filariasis?

Answer 10

Efferent lymphatic vessels

Question 11

Which mosquitoes transmit w. bancrofti?

Answer 11

Anopheles
Culex

Question 12

Describe the behavior of w. bancrofti worms

Answer 12

Nocturnal (except the South Pacific worms which are diurnal)

Question 13

What are 2 other lymphatic filariae?

Answer 13

Brugia malayi
Brugia timori

Question 14

When does lymphatic filariasis become irreversible?

Answer 14

Elephantiasis (hard, fibrous tissue)

Question 15

How can lymphatic filariasis present?

Answer 15

Hydrocele
Lower limb oedema
Chyluria

Question 16

How do you distinguish w. bancrofti from loa loa?

Answer 16

W. bancrofti - no nuclei at tail end

Question 17

What is the vector of loa loa?

Answer 17

Tabanid flies eg chrysops

Question 18

What is loa loa also called?

Answer 18

African eye worm

Question 19

How does epidemiology between lymphatic filariasis differ?

Answer 19

W. bancrofti - worldwide
Loa loa - central and western africa

Question 20

Which condition presents with calabar swelling?

Answer 20

Loa loa

Question 21

What is the vector of onchocerciasis?

Answer 21

Blackfly

Question 22

What are the 2 target sites of onchocerciasis?

Answer 22

Skin (dermatitis and leopard skin depigmentation)
Eye (river blindness)

Question 23

Which microfilariae causes intense eosinophilic inflammatory response on death?

Answer 23

O. volvulus

Question 24

Where do o. volvulus reside?

Answer 24

Onchocercal nodules (subcutaneous tissue, usually over bony prominences)

Question 25

Why is ivermectin treatment given annually for onchocerciasis?

Answer 25

Does not kill the adult worm

Question 26

Which microfilariae have wolbachia endosymbiote?

Answer 26

W. bancrofti O. volvulus

Question 27

Which stage does ivermectin affect?

Answer 27

Microfilariae

Question 28

Which microfilariae have ivermectin indicated for treatment?

Answer 28

All

Question 29

Which stage does albendazole affect?

Answer 29

Adult worm

Question 30

Which stage does doxycycline affect?

Answer 30

Female worm

Question 31

Which stage does diethylcarbamazine affect?

Answer 31

Micro + adult

Question 32

Which microfilariae have albendazole indicated for treatment?

Answer 32

Loaisis

Question 33

Which microfilariae have doxycyline indicated for treatment?

Answer 33

Bancrofti + oncho

Question 34

Which microfilariae have diethylcarbamazine indicated for treatment?

Answer 34

Bancrofti + loa

Question 35

Which drugs are contraindicated in oncho?

Answer 35

Albendazole Diethylcarbamazine

Question 36

What are the 3 groups of rickettsial infections?

Answer 36

Spotted fever group Typhus group Other - no longer rickettsias

Question 37

Which conditions fall under spotted fever group?

Answer 37

African tick bite fever Boutonneuse/Mediterranean spotted fever Tick typhus (Queensland, Siberian, Kenyan, Japanese) Rocky mountain spotted fever Rickettsialpox Flea associated (R. felis)

Question 38

Which conditions fall under typhus group?

Answer 38

Louse born (epidemic) typhus Flea borne (endemic, murine) typhus

Question 39

Which conditions are no longer rickttsias?

Answer 39

Q fever (c. burnetii) Scrub typhus (orienta tsutsugamushi) - mite borne

Question 40

Which tick causes Boutonneuse fever-like infection and what is the usual vector, transmission and reservoir?

Answer 40

R. conorii Vector - dogs Reservoir - rodents, dogs, ticks Transmission - peri-urban and peri-domestic

Question 41

What are the clinical features of Boutonneuse fever-like infection?

Answer 41

5-7d incubation Prodrome = malaise, fever, headache, nightmares, myalgia Primary lesion = eschar Rash after 3 days (coarse, maculopapular, palms and soles)

Question 42

Which tick causes african tick bite fever and what is the usual vector, transmission and reservoir?

Answer 42

R. africae Vector = cattle ticks (ambiyamma genus) Reservoirs = cattle, game, ticks Transmission = rural

Question 43

What are the clinical features of african tick bite fever?

Answer 43

Milder than Boutonneuse Multiple eschars Tender regional lymphadenopathy Rashless/scattered rash

Question 44

What are complicators of rickettsial infection?

Answer 44

Encephalitis Confusion Coma Pneumonia DIC Bleeding gangrene Renal failure

Question 45

How is rickettsial infection diagnosed?

Answer 45

Direct - immunofluorescence - PCR Serology - specific immunofluorescence - Weil-Felix (obsolete)

Question 46

Discuss treatment of rickettsial infection

Answer 46

Tetracyclines Clinical response takes 2 days In young children/pregnancy consider 2 doses doxy then macrolide Macrolide alone has slower response