Leish

Question 1

Where is Leishmaniasis most prevalent?

Answer 1

Tropical and subtropical zones

Question 2

What is the causative agent of Leishmaniasis?

Answer 2

Members of the genus Leishmania

Question 3

Who/what can be infected by Leishmania?

Answer 3

Vertebrates: Humans, dogs, rodents

Question 4

What is the (basic) life cycle of Leishmania?

Answer 4

Vector is a sand fly which transmits the parasite between vertebrate hosts. In the vector it is a promastigote and reproduces asexually in the gut. When the vector bites vertebrate, promastigotes are injected. They enter connective tissues of the vertebrate and become an amastigote. The amistigotes are released when a cell dies.

Question 5

What symptoms are associated with Leishmaniasis and what causes them?

Answer 5

Caused by breakdown of reticuloendothelial tissues. The parasites infect macrophage, bone marrow cells, spleen cells, kupfer cells of the liver

Question 6

Briefly describe the symptoms common to Visceral leishmaniasis (Kala azar)

Answer 6

Mild fever, hepatoplenomegaly, severe progressive cachexia (wasting), swollen lymph glands, leucopaenia, thrombocytopaenia, loss of hair

Question 7

How was visceral leishmaniasis (kala azar) discovered?

Answer 7

Discovered by British army physician Leishman who saw tiny nucleated structures in smears from an enlarged spleen. He knew that the patient has been taking antimalarials so he wasn’t sure what the cause was

Question 8

Describe the situation that occurs in most :eishmania infections

Answer 8

Most of the time the amastigotes do not spread beyond the site of the vector’s bite, and heal spontaneously

Question 9

What are some extra names for Leishmaniasis?

Answer 9

Kala azar, Dum-Dum Fever

Question 10

Where is Leishmania donovani mainly found and what is the fatality rate?

Answer 10

Found primarily in bone marrow, liver, spleen. Fatal in over 90% of cases if left untreated

Question 11

Describe treatment of Leishmania donovani

Answer 11

Treated with pentavalent antimonials, but natural recovery is possible and often results in lifetime immunity

Question 12

Describe mucocutaneous leishmaniasis

Answer 12

Parasites infect mucous membranes of mouth and nose

Question 13

What happens when visceral leishmaniasis treatment is not completed?

Answer 13

If it is not treated completely (for a couple of weeks) with pentavalent antimonials, the parasites are not completely eliminated, and a new syndrome develops: Post-kala-azar dermal leishmaniases (PKDL). PKDL results in large cutaneous swellings.

Question 14

How does Leishmania interact with the immune system?

Answer 14

They are intracellular and COMPLETELY HIDE from the humoral (antibody) immune response. T cells may play a role in controlling it but we are not sure.

Question 15

What is the primary zoonotic reservoir of L. infantum and why is that significant?

Answer 15

Dogs! Important because the dog and human parasites are identical

Question 16

How can PKDL be treated?

Answer 16

Has to be treated using specific medication in time to cause immunity.

Question 17

Can Leishmania parasites completely disappear from the body?

Answer 17

Probably not. People who are immunocompromised have been seen to recover and suddenly develop symptoms later.

Question 18

L. b. braziliensis causes what form of Leishmaniasis?

Answer 18

Mucocutaneous disease.

Question 19

How is the location of a Leishmania lesion related to level of infection?

Answer 19

Can only cause visceral disease at 37 degrees celcius, cannot do so at 35 degrees. The body has different external/internal temperature at different points

Question 20

Describe mucocutaneous Leishmaniasis

Answer 20

Slow healing, often extensive sore. Self cures after an extended time. After initial infection, may metastasize to mucosal surfaces of nose and mouth. Can be disfiguring, sometimes fatal if eye mucous in infected. These lesions do not self heal.

Question 21

How does death occur in mucocutaneous Leishmaniasis?

Answer 21

Indirect causes such as bacterial super infection or obstruction of airways.

Question 22

What type of ulceration does Leishmania major cause? What about L. tropica?

Answer 22

Acute, moist ulcers.

L. tropica forms slow, dry ulceration.

Question 23

Describe Leishamia ulcers. How do they heal?

Answer 23

Papulae develops at sandyfly bite, enlarges and then necrotizes. May last for many months before healing. Swelling will subside, ulcer will slowly heal, and leave a large scar

Question 24

Describe general Leishmaniasis treatment?

Answer 24

Limited to 5 currently used drugs, 1st choice being Pentostam, Glucantime, which is administered for 10-30 days at 10-20mg/day.
1nd line is Pentamidine and amphotericine B (antifungal)

Question 25

What is a useful way to deliver Leishmaniasis treatment?

Answer 25

With liposomes, because liposomes induce macrophage ingestion. Macrophages that are affected by Leishmaniasis can ingest liposome and therefore acquire the drug

Question 26

Describe some of the experimental drugs for LEishmaniasis

Answer 26

Allopurinol - used to treat gout. Can work for leishmaniasis or Chagas disease.

Ambisome - Formulation of amphotericine B in a liposome.

Ketaconazole - Interferes with growth/division of intracelllular amastigotes

Miltefosine - Botanical extract that was originally an anti-cancer. Can be given orally or with a cream but must be DONE DAILY

Question 27

How was the Tallil airforce base Leishmaniasis outbreak predicted before it even started?

Answer 27

Set up traps around the camp to catch sand flies as the temperatures got higher. Noticed large amount of sand flies and potential vectors (ex. gerbils). Superiors were informed about the potential threat. Consistent detection of sand flies happened, and eventually Leish positive sandflies were found (about 1/63).

Question 28

What were major risk factors for Leishmaniasis on the Tallil airforce base?

Answer 28

Vectors, zoonotic transmitters, lack of insecticide treated uniforms/bednets.

Question 29

How was Leishmaniasis controlled in the Tallil airforce base?

Answer 29

Sprayed buildings/tents over gerbil burrows. Nightly ULV (ultra low volume) area spraying daily throughout the summer, educating soldiers (telling them the risks of not wearing their uniform or using their bed net)