Parasitology Notes Overview

Leishmania and Transmission

• Leishmania parasites are transmitted primarily by sandflies, which invade macrophages.
• Leishmania chagasi is absent in Sudan.

Helminths and Tapeworms

• Hymenolepis nana, known as the dwarf tapeworm, measures approximately 4 cm, with eggs as the infective stage.
• Ascaris lumbricoides is recognized as the giant roundworm.
• Taenia solium has fewer uterine branches in its gravid proglottid compared to Taenia saginata.
• Cysticercus bovis serves as the infective stage for Taenia saginata, while cysticercus cellulose is for Taenia solium.
• The scolex of Taenia saginata features four suckers and a circle of hooks, in contrast, Taenia solium has four suckers but no hooks.
• Cattle act as the intermediate host for Taenia saginata, while pigs serve the same role for Taenia solium.

Human Hosts and Eye Infections

• Humans are the definitive hosts for both Taenia species.
• Roman's sign is the term for an inflamed eye caused by Trypanosoma cruzi.
• Definitive hosts for Echinococcus granulosus are dogs, with sheep and humans as intermediate hosts.

Viral Infections

• Both herpesvirus and poxvirus are classified as DNA enveloped viruses.

Protozoan Infections

• Giardia lamblia's cyst is the infective stage, with both cyst and trophozoite serving as diagnostic stages.
• The definitive host for Diphyllobothrium latum is humans, with Plerocercoid or sparganum larvae being the infective stage.

Liver Flukes and Intermediate Hosts

• The infective stage of Fasciola hepatica is metacercariae; Fasciola hepatica and Clonorchis sinensis are liver flukes, while Fasciolopsis buski is an intestinal fluke.
• The intermediate host for Wuchereria bancrofti is the female mosquito.
• Simulium (blackfly) is the intermediate host for Onchocerca volvulus.
• The deer fly (Chrysops) serves as the intermediate host for Loa loa.

Microfilariae Characteristics

• Loa loa microfilariae exhibit diurnal periodicity and are sheathed.
• Onchocerca volvulus microfilariae also show diurnal periodicity but are unsheathed.
• Wuchereria bancrofti is most detectable in blood samples from 10 p.m. to 4 a.m. due to nocturnal periodicity.

Miscellaneous Infections

• Toxoplasma gondii's infective stage is oocysts found in domestic cat feces; it does not invade the central nervous system.
• Schistosoma, a trematode, can lead to hypertension; its eggs do not contain an operculum.
• Complications from schistosomal infections arise from egg presence, causing granulomas, not adult worms.

Malaria Detection

• P.falciparum trophozoites are identified as ring stages.
• Plasmodium, a hemoparasite, is detectable using Immunochromatographic Tests (ICT) that measure HRP2, pLDH, and aldolase enzymes.
• ICT precipitation line thickness correlates with parasitemia levels.

Summary of Key Parasites and Stages

• Detailed table of parasites, their intermediate hosts, definitive hosts, infective stages, and diagnostic stages provided for further reference:
  • Entamoeba histolytica: Cysts (diagnostic), cysts+trophozoites (infective).
  • Giardia lamblia: Cysts (diagnostic), cysts+trophozoites (infective).
  • Balantidium coli: Cysts (diagnostic), cysts+trophozoites (infective).
  • Ascaris lumbricoides: Embryonated eggs (diagnostic), un/fertilized eggs (infective).
  • Trichomonas vaginalis: Trophozoite (diagnostic), trophozoite (infective).
  • Taenia saginata: Cattle (intermediate), human (definitive), cysticercus bovis (infective), eggs and proglottids (diagnostic).
  • Taenia solium: Pig (intermediate), human (definitive), cysticercus cellulose (infective), eggs and proglottids (diagnostic).
  • Diphyllobothrium latum: Cyclops (intermediate), fish (intermediate), human (definitive), plerocercoid/sparganum (infective), unembryonated egg (diagnostic).
  • Hymenolepis nana: Flea/beetle (intermediate), human (definitive), egg (infective), egg (diagnostic).
  • Trypanosoma cruzi: Triatomine bug (intermediate), human (definitive), metacyclic trypomastigote (infective).
  • Trypanosoma brucei: Tsetse fly (intermediate), human (definitive), metacyclic trypomastigote (infective).
  • Leishmania species: Sand fly (intermediate), human (definitive), promastigotes (infective), amastigotes (diagnostic).
  • Wuchereria bancrofti: Female mosquito (intermediate), human (definitive), larval stage 3 (infective), microfilaria (diagnostic).

Explore essential notes on various parasitic organisms, including Leishmania, H.nana, and A.lumbricoides. This quiz covers key characteristics, life cycles, and infective stages of these parasites. Perfect for students studying parasitology or related fields.