Parasitology lab. ü interdiction

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1 Parasitology lab ü interdiction "Humans are hosts to nearly 300 species of parasitic worms and over 70 species of protozoa, some derived from our primate ancestors and some acquired from the animals we have domesticated or come in contact with during our relatively short history on Earth". One of the largest fields in parasitology, medical parasitology is the subject which deals with the parasites that infect humans, the diseases caused by them, clinical picture and the response generated by humans against them. It is also concerned with the various methods of their diagnosis, treatment and finally their prevention & control. A parasite is an organism that live on or within another organism called the host. These include organisms such as: Plasmodium spp., the protozoan parasite which causes malaria. The four species of malaria parasites infective to humans are Plasmodium falciparum, Plasmodium malaria, Plasmodium vivax & Plasmodium ovale. Leishmania Donovan, the unicellular organism which causes leishmaniasis Entamoeba and Giardia, which cause intestinal infections (dysentery and diarrhoea) Multicellular organisms and intestinal worms (helminths) such as Schistosoma spp., Wuchereria bancrofti, Necator americanus (hookworm) and Taenia spp. (tapeworm) Ectoparasites such as ticks, scabies and lice Medical parasitology can involve drug development, epidemiological studies and study of zoonoses. ü Parasitology lab The parasitology section Laboratory provides full-service, diagnostic support for the detection of parasitic infections in domestic and wild animals. This service is provided in a timely and cost efficient manner. Accurate detection of parasites benefits animals by helping to improve animal health. The section also serves to safeguard public health through the rapid and reliable detection of zoonotic parasites. There are three main types of parasitic diseases: Protozoa: a single-celled organism. Plasmodium, which causes malaria, is an example. A protozoa can only multiply (divide) within the host 1

2 Helminths: worm parasites. Schistosomiasis is caused by a helminth. Other examples include roundworm, pinworm, trichina spiralis, tapeworm, and fluke Ectoparasites: these live on, rather than in their hosts, these include lice and fleas. ü Types of parasite There are over 1,000 known parasite species that can infect humans. These are some examples: Endoparasite: live inside the host (as opposed to ectoparasites), examples include heartworm, tapeworm, and flatworms. Those that inhabit the spaces within the host's body are called intercellular parasites, while an intracellular parasite live within the host's cells. Intracellular parasites include bacteria and viruses; they rely on a third organism, known as the vector (carrier). The vector transmits the endoparasite to the host. The mosquito is a vector for many parasites including the protozoan of the genus Plasmodium that causes malaria. Epiparasite: these feed on other parasites, a relationship known as hyperparasitism. A flea which lives on a dog may have a protozoan in its digestive tract, the protozoan is the hyperparasite. Parasitoid: the larval development takes place in or on another organism, the host usually dies. In this case there are characteristics of predation, because the host dies. Human parasites[head lice ectoparasites ], Head lice are called ectoparasites because they live on the exterior of their host.acanthamoeba: (Acanthamoeba). Affects the eye and/or brain. It exists all over the world. Individuals can become infected if they clean contact lenses with tap water. Babesiosis: (Babesia B. divergens, B. bigemina, B. equi, B. microfti, B. duncani). Affects the red blood cells. Different species live in various parts of the world. Transmitted by tick bites. Balantidiasis: (Latin name: Balantidium coli). Lives in the intestinal mucosa. Blastocystosis: (Blastocystis). Affects the intestines. Enters humans through ingested food contaminated with human/animal feces. Coccidia: (Cryptosporidium). Affects the intestines. Exists worldwide. Enters humans through ingested food contaminated with human/animal feces. 2

3 Amoebiasis: (Entamoeba histolytica). Affects the intestines. More likely in areas with high population density, poor sanitation, and tropical regions. Fecal oral transmission. Giardia: (Giardia lamblia). Affects the lumen of the small intestine. If humans ingest food/water contaminated with feces, dormant cysts may infect the body. Isosporiasis: (Isospora belli). Affects the epithelial cells of the small intestine. Exists all over the world. Fecal oral route. Leishmaniasis: (Leishmania) - Affects the skin and/or viscera. Exists worldwide in various forms. Transmitted by types of sandflies. ü Primary amoebic meningoencephalitis: (PAM) - (Naegleria fowleri). Affects the brain. Insufflation of contaminated soil, swimming pools and contaminated water. Malaria: (Plasmodium falciparum (80% of cases), Plasmodium vivax, Plasmodium ovale, Plasmodium malariae. Affects the red blood cells. Exists in tropical regions. Transmitted by the anopheles mosquito. Rhinosporidiosis: (Rhinosporidium seeberi). Affects the nose and nasopharynx. Exists in India and Sri Lanka. People who are bathing in common ponds can become contaminated when the nasal mucosa is in contact with infected material. ü Toxoplasmosis - Parasitic pneumonia: (Toxoplasma gondii). Affects the liver, heart, eyes and brain. Widespread worldwide. People can become infected after ingesting raw/undercooked pork, lamb, goat or milk. Also may exist in contaminated food or soil with cat feces. Trichomoniasis: (Trichomonas vaginalis). Affects the female urogenital tract. Can exist in males, but without symptoms. This is an STI (sexually transmitted infection). Sleeping sickness: (Trypanosoma brucei). Affects the central nervous system, blood and lymph. Transmitted by the tsetse fly. Chagas disease: (Trypanosoma cruzi). Affects the blood, muscle, nerves, heart, esophagus and colon. Transmitted through an insect bite. 3

4 ü Helminths organisms (worms)ancylostomiasis/hookworm: (Ancylostoma duodenale, Necator americanus). Affects the lungs, small intestine, and blood. Anisakiasis: (Anisakis). The human has an allergic reaction. Human can become infected when eating contaminated fish and seafood. Roundworm. Parasitic pneumonia: (Ascaris sp. Ascaris lumbricoides). Affects the intestines, lungs, pancreas, liver and appendix (the patient develops Löffler's syndrome). Tropical and subtropical regions. Roundworm: (Baylisascariasis, Baylisascaris procyonis). Affects the brain, lungs, liver and intestines. Infection comes from contaminated raccon stools. North America (rare). Tapeworm: (Cestoda). Affects the intestine. Today this parasite is rare. Clonorchiasi: (Clonorchis sinensis, Clonorchis viverrini, Dicrocoelium dendriticum). Affects the gall bladder. Humans can become infected after ingesting contaminated ants or snails. Dioctophyme renalis infection: (Dioctophyme renale). Usually affects the right kidney. Exists all over the world. Humans can become infected after eating raw or undercooked freshwater fish. Diphyllobothriasis. Tapeworm: (Diphyllobothrium latum). Affects the intestines and blood. Exists in Chile, Peru, Japan, Uganda and Europe. Humans can become infected after eating raw freshwater fish. Guinea worm. Dracunculiasis: (Dracunculus medinensis). Patient develops blisters and ulcers, affects subcutaneous tissues and muscle. Echinococcosis.Tapeworm: (Echinococcus granulosus, Echinococcus multilocularis, E. vogeli, E. oligarthrus). Affects the spleen, kidneys, lungs and liver. Mediterranean region. The human can become infected after eating foods contaminated by the feces of a carnivore, or eating offal from a herbivore. There is 3 types to detect the parasite: ü Wet mount (Direct way) : Microscope slides made from faecal specimen of the patients can be examined under low and high power. These etiological agents are identified based on their morphological/staining (bile stained or not bile stained; in case of eggs of helminthes) characteristics. Saline wet mount is made by mixing a small quantity (about 2 mg) of faeces in a drop of saline placed on a clean glass slide. The smear is then examined under microscope. Saline wet mount is used for the detection of trophozoites and cysts of protozoa, and eggs and larvae of helminthes.. 4

5 PROCEDURE: 1. Apply the patient s sample to a small area on a clean microscope slide. Remove any gross fibers and particles. 2. Immediately before the specimen dries, add 1 or 2 drops of saline with a pipette. Mix with pipette tip. 3. Cover the specimen with a cover slip. (Note: Avoid air bubbles by drawing one edge of the coverslip slightly into the suspension and lowering it almost to the slide before letting it fall. The mount should be just thick enough that newspaper print can be read through the slide.) 4. If desired the coverslip (s) can be sealed using petroleum jelly and Paraffin oil or other suitable sealing preparations. Sealing the coverslip keeps organisms from moving when using oil immersion objectives and prevents the preparation from drying out. ü Concentration method By using the Paratest container Which contains 5% formalin with water And filter with dropper. 1. Take 1 2 g from the stool sample and mix it with the formalin 2. The filter starts filtering the sample from eggs or deposit 3. After 15 minutes, add one drop of iodine stain and one drop from the sample to the slide. 4. Iodine dyes the cell walls which make it easier to check under the microscope. 5. Easy and accurate way. 5

6 ü trichrome stain It is generally recognized that stained fecal films are the single most productive means of stool examination for intestinal protozoa. The permanent stained smear facilitates detection and identification of cysts and trophozoites and affords a permanent record of the protozoa encountered. Small protozoa, missed by wet mount examinations (of either unconcentrated or concentrated samples) are often seen on the stained smear. The Wheatley Trichrome technique for fecal specimens is a modification of Gomori's original staining procedure for tissue. It is a rapid, simple procedure, which produces uniformly well-stained smears of the intestinal protozoa, human cells, yeast, and artifact material. ü Occult blood test : Uses of Occult Blood Testing Requests for occult blood testing are usually made to investigate the cause of iron deficiency anemia, or to assist in the diagnosis of bleeding lesions of the gastrointestinal tract, e.g. peptic ulcer, carcinoma, or diverticulosis. Test Methods: 1. Chemically using laboratory reagents: e.g. Aminophenazone Test. 2. Immunologically using ready-made reagents in kit tests (More expensive and usually less stable than aminophenazone test) 6