Haemoflagellates (trypanosomiasis, leishmaniasis)

Question 1

Describe the disease, vector and organism involved in the 3 main haemoflagellate associated diseases

Answer 1

1. Chagas’s disease, vector - reduvid bug (triatomine), organism - Trypanosoma cruzi
2. Human African trypanosomiasis AKA Sleeping Sickness, vector - tsetse fly, organism - Trypanosoma brucei
3. Leishmaniasis, vector - sandfly, organism - leishmania spp.

Question 2

Which vector and organism is responsible for causing Human African Trypanosomiasis (HAT) AKA Sleeping Sickness

Answer 2

Vector - tsetse fly
Organism - T.brucei

Question 3

Which vector and organism is responsible for causing American trypanosomiasis ie. Chaga’s Disease

Answer 3

Vector - reduviid bug
Organism - T.cruzi

Question 4

What vector is responsible for causing Leishmaniasis

Answer 4

Sandfly

Question 5

What are the hotspots for visceral leishmaniasis

Answer 5

Bangladesh, Brazil, India, Nepal and Sudan

Question 6

What are the hot spots for mucocutaneous leishmaniasis

Answer 6

Bolivia, Brazil, Peru

Question 7

What are the hot spots for cutaneous leishmaniasis

Answer 7

Afghanistan, Brazil, Peru, Saudi Arabia, Syria

Question 8

What type of leishmaniasis does this gentleman have and what is the prognosis/treatment?

Answer 8

Mucocutaneous leishmaniasis.
Begins with a skin ulcer that heals but after months/years, chronic ulcers appear on skin, mouth and nose leading to tissue destruction. Can be fatal if left untreated.
Treatment -

Question 9

What type of leishmaniasis is this

Answer 9

Diffuse cutaneous leishmaniasis

Question 10

What is the main foci of visceral leishmaniasis

Answer 10

Bihar, India

Question 11

Which form of leishmania is injected into bloodstream by macrophages

Answer 11

Promastigote.
Transforms into amastigotes once phagocytised by macrophages, where they multiply and are taken up by the sandfly again. Then transform into promastigotes in midgut of sandfly.

Question 12

Describe prevention methods for leishmaniasis

Answer 12

No vaccine.
Personal precautions:
- Avoid sandflies
- Keep skin covered
- Use insect repellent
- Use impregnated clothing + bed nets

Control measures:
- Survey + control vector population
- Survey + control reservoir host populations

Medical intervention:
- Inoculation against CL tried in some countries
- Early recognition (briefings + warning cards)
Early appropriate referral to a specialist

Question 13

Which country do you have both t.b. gambiense and t.b.rhodesiense

Answer 13

Uganda

Question 14

Which leishmaniasis species causes post kalazar dermal leishmaniasis

Answer 14

L.donovani which also causes visceral leishmaniasis

Question 15

Explain the mx of gHAT

Answer 15

If no clinical evidence of severe gHAT and older than 6yrs/20kg, then do LP and if <100 WBC then give PO fexinidazole.

If clinically severe gHAT then do LP, if LP shows WBC <100 then adults still get fexinidazole as bove, children get penatmidine unless WBC 6-99 in which case you get NECT.

If clinically severe gHAT and LP not done or >100 then give NECT.

Question 16

Explain the mx of rHAT

Answer 16

• If <6 yrs and >20kg, then give fexinidazole.
• If <5 WBC on LP then give suramin (unless area where onchocerciasis b/c kills microfilariae)
• If >5 WBC on LP then give melarsoprol

Question 17

Prevention and elmination of gHAT and rHAT

Answer 17

• gHAT
  ○ Case detection and treatment
  ○ Passive surveillance
  ○ Spot surveillance
  ○ Regular surveillance
  ○ Vector control
  
  • rhAT
    ○ Case detection + rx
    ○ Passive surveillance
    ○ Vector control
    NO VACCINE for either

Question 18

What are the clinical features of Chagas disease

Answer 18

Acute phase: Can be asx or symptomatic with mild illness with local swelling, LAD, redness, Romana’s/Chagoma’s. Fever, malaise, hepatosplenomegaly.

Chronic indeterminate phase (latent or asx): entered 8-10 weeks following acute phase. Lifelong seropositivity for Chaga’s, asx, no clinical disease, normal life expectancy.

Chronic phase (symptomatic) cardiomyopathy or megaviscera or both.

Question 19

Describe the management options for leishmaniasis (ML/MCL/CL/VL)

Answer 19

One of:
- IV/IM Pentavelent antimony (sodium stibogluconate/meglumine antimoniate) for 10-20 days (20-28 days for VL)
- IV liposomal amphotericin B 10-21 days
- PO miltefosine for 28 days
- Reconstructive surgery if required forML/MCL