INTRODUCTION TO PARASITOLOGY and Lab Safety

Common terminology: Parasite Host Definitive host Intermediate host Infective stage Diagnostic stage Vector Life cycle

Practical classification of parasites of medical importance: Protozoa: single-celled organisms “Multiply in human host” Helminthes: multicellular worms “Do not normally multiply in human host”

Protozoa: Amoeba: Entamoeba histolytica Acanthamoeba Species Naegleria Species Flagellates: Giardia lamlia Trichomonas vaginalis Trypanosoma species Leishmania species

Ciliates: Balantidium coli Coccidia: Blood and tissue coccidia: Plasmodium species Toxoplasma gondii Intestinal coccidia: Isospora belli Cryptosporidium parvum

Helminthes: Trematodes (Flukes): Schistosoma species Paragonimus species Fasiolopsis buski Cestodes (Tapeworms): Taenia species Echinococcus granulosus Diphyllobothrium latum Hymenolepis nana (less important)

Nematodes (Roundworms): Intestinal nematodes: Ascaris lumbricoides Enterobius vermicularis Tricuris trichiura Strongyloides stercoralis Ancylostoma duodenale Filarial and other tissue nematodes: Wuchereria bancrofti

Microscope:

Lab Safety: General lab. Safety: 1- Wear lab coats, gloves, 2- Don’t eat or drink 3- Carefully handle the samples, because it’s contagious 4- Containers must be labeled probably and after used closed very well 5- How to dispose wastes 6- Cleaning 7- Safety equipments

Must worn Lab coat Gloves

Samples used in parasitology lab: Mainly we deal with stool as a general specimen We can receive also : 1- urine, in case of S.haematobium, S.mansoni , T.vaginalis. 2- Blood, in case of Plasmodium spp, trypanosoma, W.bancrofti. 3- Vaginal discharge, in case of T.vaginalis. 4- Sputum, in case of Paragonimus spp.

5- CSF, in case of Trypanosoma spp, Naegleria 5- CSF, in case of Trypanosoma spp, Naegleria. 6- Bone Marrow, in case of L.donovani. 7- Lymph Gland Aspirate, in case of Trypanosoma spp, L. donovani. 8- Liver Aspirate, in case of E.histolytica, L. donovani. 9- Biopsies: - Skin, in case of Leishmania spp, D. medinensis. - Muscles, in case of Trichinella. 10- Duodenal Aspirate, in case of G. lamblia, S. stercoralis. 11- Rectal Scraping, in case of E.histolytica, Schistosoma spp.

How to collect stool samples: Precautions Containers Request form Time of examination Macroscopic examination Microscopic examination

Containers for stool and other samples:

Universal container for urine samples :

Blood collecting tubes:

Request form :

Macroscopic examination: Color : normally brown not pale or dark. Consistency: whether formed, semi formed, unformed, watery. Composition: Presence of mucus, blood and or Pus Odor Whether the specimen contains worms, part of the worm(segments), larva.

Microscopic examination: Wet mount : Either saline or iodine: usually we see the Cyst stage, we loose the trophozoite because it’s a fragile stage. We use 2 clean glass slides: in the first 1 drop of saline and in the other drop of iodine then by wooden stick take a small part of sample mix, cover then examine after removing your gloves .

STOOL EXAMINATION Temporary Saline smear Iodine smear saline Iodine 1% Huge number of eggs Cysts : as the iodine stains the details. Disadvantages: The trophozoites are rapidly killed by iodine and therefore become unidentifiable Huge number of eggs Trophozoites : by their motility

Other examinations of samples in parasitology lab: Serological tests: ELISA, Passive haemoagglutination test: these tests deals with serum Ag and Ab’s. Molecular tests: PCR, most commonly used in researches.