Leishmaniasis

Source: http://www.cvm.okstate.edu/instruction/kocan/vpar5333/5333iig.htm

Leishmaniasis is a parasitic disease caused by the protozoa belonging to the genus, Leishmania . This common zoonotic infection is transmitted by Phlebotemus and Lutzomyia sandflies to humans and other vertebrate hosts and may be found in over 88 countries. Over 23 different species of Leishmania exist and manifest into one of the three common forms: cutaneous, mucocutaneous, and visceral leishmaniasis.

Cutaneous leishmaniasis, also known as oriental sore , is widely distributed in the Mediterranean, Middle East, India, and Africa . This form of the disease produces one or a small number of sores primarily on the face and limbs. Initially, the sores may appear as small red bumps which may itch and grow to a sore that is flat in the center and raised on the edges. These skin lesions usually heal spontaneously within a few months.

Mucutaneous Leishmaniasis, or espundia, is generally found in South America—particularly Peru, Bolivia, Paraguay, Ecuador, Colombia, and Venezuela . With mucutaneous leishmaniasis, individuals may develop multiple large sores on the skin as well as in the mucosal area around the nose. If the infection spreads, soft parts of the nose and mouth may be destroyed.

Visceral leishmaniasis, commonly known as kala-azar , varies widely in distribution, from Africa to India and China . In most areas, individuals do not develop sores but in some cases, small lumps may appear over the entire body or in patches on the nose. Common symptoms include: weight loss, fever, low blood cell count, and enlarged spleen and liver.

There are three factors that determine the resulting disease: geographic location, host immune response, and leishmanial species. Leishmania species resemble each other morphologically. Behavioral, biochemical, clinical, immunologic, and morphologic criteria are used to distinguish the various species. Identifying the species that causes the disease is important in determing the appropriate course of treatment.

Species, Reservoirs, and Clinical Diseases

Clinical Disease

Leishmaniasis Species (Possible reservoir)

Geographic Location

Cutaneous leishmaniasis

L. tropica complex

  • L. tropica (dog)
  • L. aethiopica (rock hyrax)
  • L. major (gerbils & rodents)

Old World

L. mexicana complex

  • L. mexicana (woodrats, cat, and others)
  • L. pifanoi
  • L. amazonensis (small forest mammals, rodents, marsupials, and foxes)
  • L. garnhami
  • L. venezuelensis

New World

L. braziliensis complex

  • L. peruviana (domestic dog and probably a wild rodent)
  • L. guyanensis (arboreal sloths and anteaters)
  • L. panamensis (sloths, rodents, monkeys, procyonids)
  • L. lainsoni (agouti)
  • L. colombiensis (sloth)

New World

L. infantum

Old World

L. chagasi

New World

Mucocutaneous leishmaniasis

L. braziliensis complex

  • L. braziliensis
  • L. guyanensis
  • L. panamensis

New World

L. mexicana

New World

L. tropica

Old World

L. major

Old World

Visceral leishmaniasis

L. donovani complex

  • L. donovani (no reservoir in Indian or Kenyan area, various rodents in Sudan , dogs in China )

Old World

  • L. infantum (human is accidental host, natural infection in dogs, other Canidae, and porcupines)

Old World

  • L. chagasi (domestic dogs and cats, foxes)

New World

L. tropica

Old World

L. amazonensis

New World

Sources:

http://www.cdc.gov/ncidod/dpd/parasites/leishmania/factsht_leishmania.htm

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.4376

http://www.emedicine.com/PED/topic1292.htm#section~introduction

http://www.nature.com/nrg/journal/v7/n4/full/nrg1832.html

http://www.ebi.ac.uk/2can/genomes/genomes.html?

http://www.ebi.ac.uk/2can/genomes/eukaryotes/Leishmania_major.html

Markell and Voges. “Leishmaniasis.” Medical Parasitology . Elsevier Inc. Ninth Edition. 2006.