MEDICAL PARASITOLOGY & ENTOMOLOGY

1. MEDICAL PARASITOLOGY &ENTOMOLOGY LECTURER: SR. NORAZSIDA RAMLI

2. BLOOD & TISSUE FLAGELLATES/HAEMOFLAGELLATES

3. Morphologic forms • There are 4 morphologic forms seen in hemoflagellates: • Amastigote • Promastigote • Epimastigote • Trypomastigote -they can exist in two or more of the 4 morphologic forms  depending on the species.

4. Kingdom: Protisata • Phylum: Sarcomastigophora • Class: Zoomastigophora • Order: Kimetoplastida • Family: Trypanosomatidae • Genus:Leishmania • Species:donovani , tropica, mexicana, braziliensis

5. Leismania sp. • Can cause: • Cutaneous leishmaniasis: a localized infection of the capillaries of the skin. • Mucocutaneous leishmaniasis: cause lesions of the skin and mucous membranes, specifically of the oral and nasal mucosa. • Visceral/sistemic leismaniasis: more generalized symptoms leading to enlargement of the internal organs, especially the liver, lymph nodes and spleen.

6. Indistinguishable in appearance. • Differentiated based on: • Geographic distribution. • Pathogenesis. • Kinetoplast DNA (kDNA) analysis • DNA hibridization • Serologic testing.

7. Geographical distribution

8. Leishmania sp. • Divided into 4 groups: 1) Leishmania tropica complex – Old World Cutaneous Leismaniasis. 2) Leishmania mexicana complex – New World Cutaneous Leishmaniasis. 3) Leishmania braziliensis complex – Mucocutaneous Laishmaniasis. 4) Leishmania donovani complex – Visceral leishmaniasis.

9. Stage of life • Only have 2 stages of life: • Amastigote • Promastigote

10. Amastigote • Size: 5 by 3µm • Shape: oval to round • Nucleus: One, eccentric. • Kinetoplast: Present, Consisting of dot-like blepharoplast, with small axoneme and prabasal body. • Flagellum: absent

11. Promastigote • Size: 9-15µm • Shape: long and slender. • Nucleus: one, central. • Kinetoplast: Anterior end of the organism, no undulating membrane. • Flagellum: Single, anterior free flagellum.

12. Leishmania tropica complex – Old World Cutaneous Leismaniasis. • L. tropica - mediterranean region, middle East, Armenia, Caspian region, Afghanistan, India and Kenya (particularly in urban areas) • L. aethiopica – Highlands of Ethiopia, Kenya and Southern Yemen. • L. major – Desert regions of Turkmenistan, Uzbekistan and Kazakhstan, Northern Africa and the Sahara, Iran, Syria, Israel and Jordan.

13. Morphology • Cause a chronic disease: cutaneous leishmanisis. • Also known as Oriental sore, Delhi boil and dry or urban cutaneous leishmaniasis. • Characterized by: production of dry, raised, ulcerated lesions at bite sites. • Vectored by: tiny sandflies of the genera Phlebotomus.

14. L. tropica

15. Vector: Phlebotomus sandfly

16. Sandfly vs mosquito mosquito sandfly

18. Life cycle • Only the female sandfly transmits the parasites. • Vector draws a blood meal from an infected host  amastigotes form transform into promastigotes n multiply (within fly gut) promastigotes migrate to the pharynx  fly feeds again, transmitted to a new host  engulfed by reticuloendothelial cells  amastigotes multiply repeatedly by binary fission.  cell ruptures  amastigotes invade new macrophages and perpetuate the cycle.

19. Life cycle

20. Transmission & Pathogenesis • Incubation period vary from several weeks to as three years. • First sign of cutaneous leishmaniasis= the development of a small red papule at the initial site of the insect bite. • A local granulomatous response leads to the formation of a crateriform lesion  2cm or more. • L. tropica n L. aethiopica produce dry lesions. • L. major produce moist lesions with a serous exudate. • Lesions can heal spontaneously but may leave serious scars.

21. Contact spread of infection also possible. • Patient may produce multiple sores by scrathing and autoinoculating normal skin. • Diffuse cutaneous leishmaniasis (DCL): -occur in anergic patient (who is unable to amount an adequate immune respon). -characterized by the presence of multiple nodular lesions, particularly on the face and limbs. -loaded with parasites and do not heal spontaneously.

22. DCL

25. Laboratory Diagnosis • Montenegro (leishmanin) skin test -delayed hypersensitivity reaction provoked by a suspension of killed leishmanial promastigotes administered intradermally. -local inflammatory reaction appears at the site of injection within 48-72 hours. • Microscopy examination • Isoenzyme studies • Molecular diagnostic technique- PCR • Serologic test – ex: indirect fluorescent antibody assay.

26. Treatment • Sodium stibogluconate (antimony sodium gluconate: Pentostom). • Meglumine antimonate • Glucantime • Ampotericin B • Ketoconazole

27. Prevention • Use of bed netting • Insect repellent and residental spraying • Rodent control in reducing transmission. • Individuals with active lesions  promptly treated, wound covered  to prevent autoinfection and further insect transmission to other individuals.

28. Leishmania mexicana complex – New World Cutaneous Leishmaniasis • L. mexicana – Belize, Guatemala, and the Yucatan peninsula. • L. pifanoi – Amazon river basin and parts of Brazil and Venezuela. • L. amazonensis – Amazon basin of Brazil. • L. venezuelensis – forests areas of Venezuela. • L. garnhami – Venezuelan Andes.

29. Morphology • Distribution extends from Southern Texas in the United states, through Mexico, Central and South America. • L. mexicana causes chiclero ulcer or Bay sore. • L. pifanoi causes DCL. • L. amazonensis causes cutaneous and DCL. • L. venezuelensis causes cutaneous leishmaniasis. • L. garnhami causes Venezuelan Andean cutaneous leishmaniasis.

30. Life cycle • Transmitted by Lutzomiya sandfly • Reservoir host: rodents, opossums, domestic dog, cat etc. • Life cycle same with L. mexicana complex.

31. Life cycle

32. Vector: Lutzomiya sandfly

33. Transmission & Pathogenesis • L. mexicana - produces a lesion known as chiclero ulcer or Bay sore – common among workers who collect chicle gum from the Chicazapote trees in the rain forest in Nicaragua, Guatemala, Belize and the Yucatan peninsula of Mexico. • Clinical manifestation: a single cutaneous papule, nodule or ulcer located on the ear or face. Lesion generally heal spontaneously but may cause cartilage destruction and gross disfigurement.

34. L. pifanoi and L. amazonensis – produce a single but more likely to progress to the DCL – the majority patient infected, clustered in the Amazon river Basin of Brazil and Venezuela. • Clinical presentation of DCL may be confused with Leptomatous Leprosy. • L. garnhami and L. venezuelensis – assosiated with cutaneous leishmaniasis in rural parts of Venezuela – infection with either organism present with a solitary lesion that is usually self-limiting.

35. Leptomatous Leprosy Picture: Mildly elevated indurating nodules are seen on the face and extremities (gross findings).

37. Diagnosis • Giemsa stained smears –amastigotes will be seen. • Cultivation – promastigotes forms can be obtained. • Immunological testing methods.

38. Treatment • In most cases, the infections are self-limiting and require no treatment. • Treatment is paramount if: -the lesion should endure or -threaten cartilaginous structures; ear,nose. • Therapeutic agents: same as the treatment of Oriental sore.

39. Prevention • Same as the prevention ways of Oriental sore. • applied insect repellent to the skin and garments along with aerial spraying.

40. Leishmania braziliensis complex – Mucocutaneous Leishmaniasis • L. braziliensis – Mexico to Argentina • L. panamensis – Panama and Columbia • L. peruviana – Peruvian Andes. • L. guyanensis – Guiana and parts of Brazil and Venezuela.

41. Morphology • Cause infections throughout the Americas from Mexico to Argentina. • The distinguishing feature of these infectious is the development of ulcers on or about the oral and nasal mucosa • L. braziliensis causes espundia. • L. guyanensis causes pain bois. • L. peruviana causes uta. • All cause considerable morbidity and mortility in the endemic areas.

42. espundia

43. Life cycle • Same with L. mexicana complex • Vector: Lutzomyia and Psychodopygus sandflies.

44. Pathogenesis • The primary lesion-same manner as the Oriental sore: macrophage ingest the parasites  become heavy laden with replicating amastigotes  tissue damage. • Invade mucous membranes of the mouth and nasopharynx. • Spread by: direct extension of the primary lesion or metastasis via the bloodstream or lymphatics. • Progression of disease may take years.

45. Resulting disease: may produce ulcers that erode soft tissues of the face and palate or form polyp-like appendages in the nasal cavity. • Patient commonly present with enlargement of the regional lymph nodes and secondary bacterial infections. • Untreated  patients generally succumb to these secondary infection or to starvation if destruction of the oral cavity is extensive.

48. Diagnosis • By demonstrating amastigotes of Leishmania in Giemsa stained smears or biopsy material from the edge of an active ulcer. • Cultivation. • Serologic test. • Montenegro skin test.

49. Treatment • Sodium antimony (Pentostom). • Cycloguanil pamoate (Camolar). • Amphotericin B (Fungizone). • Meglumine antimonate • Glucantime • Ketoconazole

50. Prevention • Personal protective measures such as :protecting clothing, insect repellents and etc. • Vector control • Reservoir host control • Public health educational programs. • Prompt treatment of infected individuals  to break the cycle of disease transmission.