Medical Parasitology Lesson 1 FTF

Parasitology

Studies parasites across all living organisms

Medical Parasitology

Deals with protozoans that causes human infections and the diseases they cause

Protozoa

Unicellular, Kingdom Protozoa

Helminths

Multicellular, Kingdom Animalia

Protozoology

Study of protozoans

Helminthology

Study of Helminths

Amebae, Flagellates, Sporozoa, Cilliatea

Types of Protozoan

Nematodes, Cestodes and Trematodes

Types of Helminths

Entamoeba coli & Naegleria fowleri

Example of Amebae

Giardia lamblia & Trichomonas vaginalis

Example of Flagellates

Plasmodium falciparum, Babesia microtti, Taxoplasma gondii

Examples of Sporozoa

Balantidium coli

Examples of Cilliate

Balantidium coli

The only ciliated parasite that could infect humans

Entamoeba coli

Harmless gut bacteria

Naegleria fowleri

Brain-eating amoeba that can be obtained from freshwaters

Giardia lamblia

Causes intestinal problems and diarrhea called giardiasis

Trichomonas vaginalis

Common STI and causes strawberry cervix

Plasmodium falciparum

Obtained from a vector of a female anopheles mosquito bite (malaria)

Babesia microtti

Bear ticks

Taxoplasma gondii

Accidental ingestion from infected cat feces

Parasites

Living organisms that rely on their host for survival

Ectoparasites, Endoparasites, Free-living

Classification of Parasites

Endoparasites

Parasites that live within the host (infection)

Ectoparasites

Parasites living at the surface of the host (infestation)

Free living

Can be parasitic, can also be not, depends when ingested accidentally

Obligate facultative abberant accidental

Types of endoparasites

Obligate parasite

Cannot exist without host

Facultative parasite

Can be free living and can be parasitic, can depend and not depend

Aberrant parasites

Parasites that shouldnt be in that part of an organ

Accidental parasites

Parasites that is ingested by an unusual organism

Definitive host

A type of host where the parasites reach sexual maturity and undergoes sexual reproduction

Intermediate host

A type of host where the larvae lay eggs and mature, asexual reproduction happens here

Paratenic Host

A host where the larval stage of the parasite is viable without development

Accidental Host

Type of host that is unusual to that parasite

Zoonosis

A term defined as a diseases that is naturally transmitted from a vertebrate animal to human and vv

Protozoal zoonosis, Helminthic zoonosis, Anthrophozoonoses, Zooanthroponoses

Types of Zoonosis

Balantidium coli

Example of Protozoal zoonosis

Taxoplasma gondii

Example of Helminthic zoonosis

Rabies

Example of Anthropozoonoses

Taenia solium

Example of Zooanthroponoses

Symbiosis

Type of parasite relationship where both of them isnt harmed and just living together

Commensalism

Type of parasite relationship where one is benefitting and one is not harmed

Mutualism

Type of parasite relationship where both benefits

Parasitism

Type of parasite relationship where one is benefitting and one is harmed

ascaris lumbricoides, giardia lamblia, estorobius vermicularis

Examples of Parasites with direct life cycle

Taenia solium, Plasmodium falciparum, Schistosoma mansoni

Examples of parasites with indirect life cycle

Contamination, Food, Vectors, Self

Sources of Infection

Oral, Skin, Vector, Direct, Vertical, Iatrogenic

Modes of Infection

Extrinsic incubation period

Interval between the entry if the parasite in a vector and the time it becomes infectious

Pathogenesis

A biological process where a diseases develops in the body

lytic necrosis, trauma, allergic.manifestation, physical obstruction, neoplasma and Space occupying lesions.

Mechanisms of Pathogenesis

Lytic necrosis

Enzymes releasesd by parasites ex. Entamoeba histolytica that dissolves the intestinal lining

Trauma

Physical or mechanical damage inflicted by parasites. Ex. Hookworms using their mouthpart to anchor themselves and damage the tissue

Allergic manifestation

Where it is mediated by immune response to the parasite than the parasite directly causing the symptoms

Physical obstruction

When a parasite gets into vessels, ducts and etc that is a passage and disrupts fluid or organ mechanisms

Neoplasia

When the prolong presence of the parasite triggers an uncontrolled growth of cell due to the desperation of trying to fix the constant damage in that organ ex. Bladder cancer by Schistoma haematobium

Space occupying lesions

When a parasite makes a cysts that presses another organ in close proximity

Liquid Stool Time

30 mins

Soft stool time

1hr

Hard/Formed stool time

24hrs

Trophozoites

Immature version of giardia lamblia or entamoeba coli that is seen when the stool is soft

Oocysts

Mature _____ of Giardia lamblia and Emtamoeba coli that is seen on a hard stool

Saline Wet Mounts, Iodine Staining & Eosin Staining

Examples of Wet Mount staining

Saline Wet Mounts

Type of Mount used to detect live motile trophozoites

Iodine Staining

A type of stain that is a standard method of staining and is used to confirm identity of protozoan cysts

Eosim staining

Type of stain where it stains the BG and insicates the vuability of cysts

Permanent sgained smear

Used to confirm intestinal protozoan

Sigmoidoscopy material

Scraping or aspirates from lower colon are collected to examine amoebae attached to inestinal ulcers

Duodenal capsule technique

The patien swallows a duodenal capsule containing a weighted string to capture parasites like Giardia

Balamuth’s and Drbohlav’s

Culture method dedicated to isolate prorozoan species

Charcoal culture

Incubation method for growing and identifying hookworms and strongyloides

Egg counting method

Calculations to detect the intensity of an infection, track diseases and evaluate treatment efficiency

Sedimentation and Flotation

Concentration methods

Sedimentation Method

Using a centrifuge or gravity to separate parasites from excess fecal debris

Flotation method

Using a high specidic gravity liquid called zinc sulfate flotation

ExaMi