Clinical Parasitology/Lecture - Introduction to Parasitology - PDF

1ST SEMESTER CLINICAL PARASITOLOGY / LECTURE SY 2023-2024 para311 INTRODUCTION TO PARASITOLOGY...

1ST SEMESTER CLINICAL PARASITOLOGY / LECTURE SY 2023-2024 para311 INTRODUCTION TO PARASITOLOGY PARASITOLOGY Parasite Lives on or in the host usually on An area of science which deals with the study of a larger organism which provides organisms living permanently or temporarily on or physical protection and within another organism. nourishment. The branch of biology or medicine concerned with the study of parasitic organism. Host Harbours parasite and gives It is the study of parasites, their hosts, and the nourishment. relationship between them. **two organisms in parasitology: parasites HOST-PARASITE RELATIONSHIP (benefiting), host (being harmed) ** Symbiosis: living together of unlike organisms, Concerned with the phenomena of dependence of protection, or other advantages to one or both one living organism on another. partners. DIVISIONS OF PARASITOLOGY Mutualism: relationship is beneficial to both Divisions Description organisms. Protozoology Protozoans: small, unicellular **ex. Termites and Flagellates in their digestive organisms, which contain nucleus system, termites provide habitat for flagellates in and functional organelles their GIT, in return, flagellates are digesting the woods that was consumed by the termites** Helminthology Worms: larger, multicellular Commensalism: parasite derives benefit without (Study of the organisms, normally visible to the reciprocating and without injury to the host or both Worms) naked eye in their adult form. **ex. Entameba coli in the intestinal lumen, is Medical Insects and arthropods. supplied with nourishment and protected from Entomology **in the life cycle of the parasite, harm. It does not give damage to the host nor gives they are transmitted by vectors a pathological condition; the host does not benefit which is the insects and from the relationship. arthropods** **one organism benefits and the other is unharmed Medical Concerned primarily with the Parasitism: relationship where one organism, the Parasitology parasite that affects humans and parasite, lives in or on another, depending on the their medical significance, as well latter for its survival and usually at the expense of as their importance in human the host communities. **ex. Entameba histolytica which derives nutrition from the human host, and it also causes amoebic Tropical Branch of medicine which deals dysenteric** Medicine with tropical diseases and other special medical problems of PARASITES ACCORDING TO THE MODE OF tropical regions. LIVING **tropical region: places with 2 Ectoparasites: living outside the body of the host. seasons, wet and dry season** **ex. Lice living in our head/hair** **infestation - the presence of ectoparasites** Tropical An illness which is indigenous to Endoparasites: living inside the body of the host. Disease or endemic in tropical area but **infection – the presence of endoparasites** may also occur in sporadic or **a parasite is considered as erratic when it is epidemic portions in areas that are found in an organ which is not its usual not tropical. habitat** **many tropical diseases are Facultative parasites: able to live outside or parasitic in nature, mostly inside the host and lead both to a free and parasitic transmitted by insect bites** existence. Page | 1 PARA311 LEC 1st SEMESTER | INTRODUCTION TO PARASITOLOGY **with or without the host they can survive** **allow parasite’s life cycle to continue and they **if they are not inside the host, they are in their become additional source of human infection** pre-living stage** Paratenic host: harbours a stage of the parasite Obligate parasite: completely dependent to the where in no further development in parasite takes host for its existence throughout its life place Accidental/ Incidental parasite: establishes itself **also called as dead-end host** in the host in which it does not ordinarily live. **ex. If you harbour larvae, inside your body it **animal parasites that is accidentally will stay as a larvae and will not further develop transmitted to humans** into an adult parasite** Occasional/ Periodic: seeks its host intermittently to obtain nourishment. SOURCE OF EXPOSURE TO INFECTION **only visits a host during the feeding time/ Pathogens: can be animal parasites that are when they only need nourishment** harmful and frequently cause mechanical injury to Saprophytes: live in organic substances in state of their host decomposition **can be: **ex. Animal carcass decaying, the parasites ▪ Pathogenic - disease-causing thriving through it are called Saprophytes** ▪ Non-pathogenic – not causing Erratic: those that live in an organ different from disease** the one it usually parasitizes Carrier: harbours a particular pathogen without Zoonotic: animal parasites, non-human parasites manifesting signs and symptoms that may cause human infections (**asymptomatic carrier**) Temporary parasites: free living during part of Exposure: process of inoculating an infective existence, larval stage has a different host from its agent adult stage. Infection: establishment of the infective agent in **Intermediate host – different host that they the host will transfer to** Incubation period: period between infection and Permanent parasites: remain on the body of the evidence of symptoms host in all stages of its life cycle. **time frame from acquiring the infection to the manifestation of signs and symptoms (usually PARASITES ACCORDING TO PATHOLOGIC 7-14 days)** LOCATIONS **talking about the signs and symptoms** Spurious/ Coprozoic parasite: passes digestive Pre-patent period: biological incubation period, tract of humans without infecting them period between infection and acquisition of the Coprophilic parasite: parasite multiply in fecal parasite and evidence or demonstration of infection matter outside the human body **demonstration of infection – nakikita kapag Hematozoic parasite: lives inside the red blood yung parasitic morphology is nakikita na sa cells sample Cytozoic parasite: lives inside the cells or tissues **ex. In case of Malaria, the appearance (ring Coelozoic parasite: lives in body cavities (**lymph formation, tropozoites, gametocytes) will not nodes, lymph channels**) appear immediately on the blood sample after Enterozoic parasite: lives in the intestine you are bitten by a mosquito. It needs time to develop parasitic morphology. That period is TYPE OF HOST Pre-patent period** Definitive host: final host, harbours the adult and Autoinfection: infected individual becomes his sexually mature form of parasite. mature own direct source of infection Intermediate host: harbours the larvae or asexual Superinfection or hyperinfection: already stage of the parasite. immature affected individual is further infected with the same Reservoir host: animal that harbours the same species leading to the massive infection with the parasite of man. parasite. **ex. Pigs are reservoir host of Balantidium Co-infection: simultaneous infection of a host by coli** two or more parasite. Page | 2 PARA311 LEC 1st SEMESTER | INTRODUCTION TO PARASITOLOGY **usually occurs in soil-transmitted illness** Arthropod / Vector transmitted **ex. Ascaris lumbricoides and co-infection Food-borne with Trichuris trichiura or hookworm (since they Water-borne are all encountered on soil, you can acquire Skin penetration them simultaneously) Congenital transmission T. vaginalis A. Contaminated soil and water Direct contact PORTAL OF ENTRY Lack of sanitary toilets and use of night soil **night soil is a fertilized soil, in which the By mouth: most common area of invasion fertilizer used is human excreta or feces -- used entrance for intestinal protozoa historically as it improves soil fertility** Skin penetration Soil: Ascaris lumbricoides, Trichuris trichiura, Intranasal: inhalation of eggs Hookworm, Strongyloides stercoralis Transplacental infection Water: Amoeba, Flagellates, Blood Flukes Transmammary Sexual intercourse B. Food containing immature infective stage of parasite PORTAL OF EXIT Stool Consumption of undercooked or raw freshwater Urine fish, crab, snail, beef, and pork Sputum C. Arthropods, blood sucking insects and other Blood wild or domesticated animals Tissue aspirates and biopsy Mosquitoes (Filaria and Malaria) Orifice swab Triatoma bugs (Trypanosoma cruzi) Discharge Sandflies (Leishmania) NOMENCLATURE Cats, dogs, and house rats Classified according to the International Code of D. Another Person Zoological Nomenclature Scientific name is Latinized. Beddings and clothing Generic names consist of a single word written in Immediate environment he has contaminated. initial capital letter; the specific name always E. One’s self begins with a small letter. Autoinfection: self is the source of infection Names of genera and species are italicized or Enterobius vermicularis, Hymenolepis nana, and underlined when written. Strongyloides stercoralis Ex. TYPE OF VECTORS o Kingdom: Animalia Vector: responsible for transmitting the parasite from o Phylum: Nematoda one host to another. o Class: Secernentea Types of Vectors: o Order: Ascaridida o Family: Ascarididae a. Biological vector: the parasite is seen inside o Genus: Ascaris the body of this organism and the parasite o Species: Ascaris lumbricoides needs this organism for its development. **they are part of the life cycle of parasite** TYPES OF LIFE CYCLE Ex: mosquitoes, tsetse flies Simple or complicated (**if it has a lot of b. Mechanical vector: responsible only for intermediate host**) transporting the parasite, the parasite is only **as the life cycle becomes complicated, the seen on the surface of this organism and lesser chance for an individual parasite to there will be no development on the parasite. survive** Ex: cockroaches, house flies Most parasitic organisms attain sexual maturity at MODE OF TRANSMISSION the definitive host. Soil transmitted Page | 3 PARA311 LEC 1st SEMESTER | INTRODUCTION TO PARASITOLOGY Larval stage of parasite may pass through different o Indirect: counting helminth egg excreted in stages in an intermediate host. feces, expressed in egg per gram As life cycle becomes complicated, the lesser DISTRIBUTION OF DISEASES chances are for the individual parasite to survive Sporadic: appears only occasionally in one or at LIFE STAGES OF A PARASITE most a few members of the community Ova Endemic: there is a constant or steady moderate Egg level of disease in human population or the usual Larva prevalence of the disease in a geographic area Trophozoite Epidemic: there is an increase, often sudden Cyst outbreak or rise of incidence above the normally Adult expected in human population Pandemic: when the disease has been MODE OF REPRODUCTION disseminated in extensive area of the world SEXUAL PATHOPHYSIOLOGY AND SYMPTHOMOLOGY OF Oviparous: "egg birth”, give birth to eggs that PARASITIC INFECTIONS must develop before hatching Traumatic or physical Ovoviviparous: ones that produce eggs but retain damage: when parasites them inside the female body until hatching occurs, invade the skin and other so that "live" offspring are born tissues causing Larviparous/ Viviparous: being born alive without destruction. eggs. ASEXUAL ex. Creeping eruption caused by Hookworm Binary fission: division in half – causes severe itching, Parthenogenesis: unfertilized ovum develops blisters, and red-growing directly into a new individual, natural form of winding rash. asexual reproduction in which growth and Lytic necrosis: development of embryos occur without fertilization secretory and excretory by male sex cell products elaborated by **female parasite can fertilize her own eggs, it many parasites allow is being applied to Nematodes, particularly them to metabolize Strongyloides stercoralis** nutrients obtained from EPIDEMIOLOGIC MEASURES the host and store these Epidemiology: science concern with the for energy production. propagation of the disease, study of patterns, ex. Entamoeba distribution, and occurrence of disease histolytica trophozoite Incidence: number of new cases of infection in rectal biopsy – they appearing in a population in a given period of time secrete cysteine **absolute number** proteinase to invade our Prevalence: usually expressed in percentage, tissues. number of individuals in a population estimated to be infected with a particular parasite at a certain Tissue reactions: time cellular proliferation, Cumulative prevalence: percentage of individuals white cell infiltration at in the population infected with at least one parasite. the side of the parasite Intensity of infection: number of worms per ex. Helminth infection infected person (worm burden) (eosinophil-mediated o Direct: counting expelled worms during cytotoxicity against treatment filariform larvae of Strongyloides Page | 4 PARA311 LEC 1st SEMESTER | INTRODUCTION TO PARASITOLOGY stercoralis) – causing bed rest increased blood Deworming: use of anti-helminthic drugs in an eosinophil counts individual or public health program. Toxic allergic Cure rate: usually expressed in percentage, phenomena: when number of previously positive subjects found to be proteins or other egg-negative in examination of a stool or urine metabolites of the sample using a standard procedure at a set time parasites are introduced after deworming. into the body, there is Egg reduction rate: percentage fall in egg counts sensation to the foreign after deworming based on examination of a stool substance which may or urine sample using a standard procedure at a produce set time after deworming. hypersensitization to LEVEL OF TREATMENT anaphylactic shock. Selective treatment: individual-level deworming Ex. Punctate keratitis with selection of treatment based on a diagnosis of Deprivation of the an infection or based on presumptive grounds. host’s essential Targeted treatment: group-level deworming where nutrients and the risk group to be treated (with or without prior substances: the diagnosis) may be defined by age, gender, or other parasite competes with social characteristics irrespective of infection its host for the available status. supply of vitamin. Universal treatment: population-level deworming in which the community is treated irrespective of Ex. Hookworm infection age, gender, infection status or other social can causes massive characteristics. intestinal bleeding, they Coverage: proportion of target population reached will stick into the by an intervention. intestinal wall causing Drug resistance: genetically transmitted loss of chronic blood loss susceptibility to a drug in a worm population that resulting to iron- was previously sensitive to the appropriate deficiency anemia therapeutic dose. FACTORS THAT DETERMINE THE INTENSITY OF **drug abuse causes drug resistance** PARASITIC INFECTION EFFICACY AND EFFECTIVENESS Topography of locality Efficacy: effect of a drug against an infective agent Social condition in deal experimental conditions and isolated form Age of any context. Hygienic measure **performance of the intervention under ideal Sewage disposal or controlled circumstances** Water supply **does the intervention/drugs work?** TREATMENT **measures how well the drugs produce its There are several options for treating parasitic desired result** infections. Many of these drugs are toxic to the host Effectiveness: measure of the effect of a drug and care should be exercised when selecting the against infective agent in a particular host, living in proper course of treatment. a particular environment with specific ecological, antiparasitic medications immunological, and epidemiological determinants. change in diet. **not just the effect of drug, it is the vitamin supplements performance under the real world condition** fluid replacement **does the intervention benefits the patient?** blood transfusion Page | 5 PARA311 LEC 1st SEMESTER | INTRODUCTION TO PARASITOLOGY **refers how easy the drugs are to use and the - Disease is present but there were no new cases possible side effects** encountered **is it safe to consume?** **if the drug is effective, must be safe to consume** PREVENTION AND CONTROL Morbidity control: avoidance of illness caused by infections, may be achieved by periodically deworming individuals or groups, known to be at risk of morbidity. **Ex. Administering Deworming** Information-education-communication (IEC): health education strategy that aims to encourage people to adapt and maintain healthy life practices. Environmental management: planning, organization, performance and monitoring of activities for the modification and/or manipulation of environmental factors or their interaction with human beings. o preventing or minimizing vector and intermediate host propagation o reducing contact between humans and the infective agent Environmental sanitation: intervention to reduce environmental health risk. o safe disposal and hygienic management of human and animal excreta, refuse and wastewater. o control of vectors, intermediate host, and reservoir of diseases o provision of safe drinking water and food safety o housing that is adequate in terms of location, quality of shelter and indoor living conditions, o facilities for personal and domestic hygiene o safe and healthy working conditions Sanitation: provision to access to adequate facilities for safe disposal of human excreta, usually combined with access to safe drinking water ERADICATION AND ELIMINATION Disease eradication: permanent reduction to zero of the worldwide incidences of infection caused by a specific agent, as a result of deliberate effort. Once this is achieved, continued measures are no longer needed. Disease elimination: reduction to zero of the incidences of a specified disease in a defined geographical area as a result of deliberate effort. Continued intervention and surveillance are still required. Page | 6  1ST SEMESTER CLINICAL PARASITOLOGY / LECTURE SY 2023-2024 para311 INTESTINAL AND EXTRAINTESTINAL AMOEBAE PROTOZOA CLASSIFICATIONS OF PROTOZOAN PARASITES Proto (first), Zoa (animals) PHYLUM SUBPHYLUM SPECIES A unicellular organism that performs all the Acathamoeba functions: reproduction, digestion, respiration, Endolimax nana excretion, etc. Entamoeba coli Considered as eukaryotic cells because they Sarcomastigophora Sarcodina Iodamoeba possess true nucleus. Composition: butschlii o Nucleus: usually single but may be double or Entamoeba multiple; contains one or more nucleoli or a dispar central karyosome Entamoeba ▪ Karyosome - DNA-containing body that is gingivalis situated peripherally or centrally in the Entamoeba nucleus, and it is found in the intestinal histolytica amoebae; It position within the nucleus is used to identify the intestinal amoebae. Naegleria fowleri ❖ Centrally – Entamoeba histolytica Chilomastix ❖ Peripherally – Entamoeba coli mesnili o Cytoplasm Giardia lamblia Mastigophora ▪ Endoplasm: inner (often granulated), dense Trichomonas part; contains Golgi body, Endoplasmic vaginalis reticulum, food vacuoles, and refractive vacuoles Dientamoeba ▪ Ectoplasm: outer (non-granulated), typically fragilis watery; homogeneous part; serve as organ Trichomonas for locomotion tenax o Structures for locomotion: pseudopodia Ciliophora Balantidium coli (temporary prolongation or finger like Babesia spp. projections), flagella (hair-like projections), cilia (tail-like projection surrounding the body of Cryptosporidium protozoans), undulating membrane (organ that Apicomplexa hominis supports the motility of the parasites) Cyclospora o Plasma membrane: controls secretions and cayetanensis excretions Isospora belli o Cytostome: cell mouth Plasmodium spp. o Chromatoidal bodies: storage for glycogen protein Toxoplasma gondii Enterocytozon bineusi Microspora Encephalitozoon spp. Vittaforma cornea Pleistophora spp. Brachiola vesicularum Microsporidium spp. analyze mo lang 'yung sa classification and try mo rin alamin 'yung pagkakatulad nila bawat classification Page | 1 ex. location, mot, and treatment if possible PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Subphylum Sarcodina o Intestinal and extraintestinal amoebae, and free- living amoebae o Came from the word “sarcos” means flesh or body. o Includes those parasites with no permanent locomotory organ but they move with the aid of temporary prolongation of the body called as pseudopodia. Subphylum Mastigophora o Came from the word “mastics” means whip or flagellum. o Includes those protozoa which possess whip-like flagella. Ex. Atrial flagellates, reproductive organ flagellates, blood, and tissue flagellates Phylum Ciliophora o These protozoa are motile by means of Cilia, or hair-like projection covering their entire body surface. PHYLUM SARCOMASTIGOPHORA: Subphylum o Balantidium coli – causes Dysentery. Sarcodina Phylum Apicomplexa GENERAL RULES FOR AMEBAE o Formerly known as Sporozoan o Members of this group possess, at some stage of All Entamoeba are COMMENSAL except for life cycle, the apical complex that is used by the Entamoeba histolytica. parasites for the attachment to the host’s cell. o Presence of amoeba in any part of the body is o In this group belongs: Malarial parasites, termed as amebiasis and it is exclusively applied Plasmodium species and Coccidian parasites. to Entamoeba histolytica (because it is the only Phylum Microspora pathogenic amoebae) o There are intracellular parasites which frequently With pseudopodium (false feet): finger-like cause disease to an immunodeficient subject / structures for movement immunocompromised patient. Undergoes ENCYSTATION except for E. gingivalis and Dientamoeba fragilis. 2 STAGES COMMONLY ENCOUNTERED IN THE Inhabits the LARGE INTESTINE except for E. PROTOZOANS gingivalis (because they are seen in the mouth, ENCYSTATION particularly the gums) stage forming a cyst or becoming enclosed to a Asexually multiplies through binary fission (a single capsule, this event takes place in the rectum of the organism divide, either longitudinally or transversally host as feces are dehydrated or soon after the feces into two or more equal number of parasites) have been excreted. Entamoeba histolytica A process of becoming a cyst The only pathogenic amoeba EXCYSTATION MORPHOLOGIC FORMS escape from cyst or envelope, produces a trophozoite 1. Trophozoite: divides through “binary fission”, from the cyst stage, and it takes place in the large capable of encystation intestine of the host after the cyst has been ingested. A process of becoming a trophozoite Factors that can contribute to encystation: Ex. You have ingested a contaminated water that o Overpopulation contains the cyst, inside your intestines, those cysts ▪ If there is an overpopulated trophozoite in the will transform to become trophozoites. large intestine, there is a limited food supply and availability of oxygen. Trophozoite are in the feeding stage, so for them to survive, they will transform as a cyst. Page | 2 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae o pH change TROPHOZOITE CYST ▪ In the intestines, if the environment becomes Vegetative and motile Non-motile, non- acidic, since the trophozoites are fragile, they stage (feeding stage) feeding stage will transform to become a cyst. Found in fresh Found in soft to o Food supply watery, soft, or semi- formed stool. o Availability of oxygen formed stool. Resistant to acidic pH 2. Precyst: contains large glycogen vacuole and two Fragile chromatid bars and then secretes a highly retractile cyst wall around it and becomes cyst. 3. Cyst: with protective thick cell wall (hyaline), capable Life Cycle of Entamoeba histolytica of excystation 4. Metacyst: liberated quadrinucleate amoeba during excystation INFECTIVE STAGE mature quadrinucleate cyst passed in feces. o If we ingested a Trophozoite, it would not initiate an infection because Trophozoite is not an infective stage of the parasite, and because they are fragile, they will not survive with pH acidity of the stomach. MODE OF TRANSMISSION Ingestion of contaminated food and/or water with E. histolytica cyst Fecal-oral route In the life cycle of the parasite, you should take note of Other MOT: Venereal transmission – transmitted the following: through sexual intercourse (anal sex, oral sex) 1. Mode of transmission Direct colonic inoculation of contaminated enema 2. Infective stage equipment 3. Diagnostic stage – stage where we can see the o Enema equipment – equipment that is injected parasite in the sample being submitted in the in the rectum, and the content should be expelled. laboratory. o Ex. You used enema equipment with patient 4. Final host infected with Entamoeba histolytica, and then you 5. Intermediate host used it again with other patient and have direct In the life cycle of Entamoeba histolytica, since inoculation because you did not disinfect the humans are the only host, it is considered as an obligate equipment after you used it to a patient with the parasite (meaning all throughout the life stage, it will stay infection. in the same host). It has only 1 host and have no For Entamoeba histolytica, they have no intermediate host. morphologic difference with any other parasites that are Infective stage: Quadrinucleate and it is resistant to non-pathogenic. So, it is quite challenging to identify gastric acidity, and it can survive in moist Entamoeba histolytica based on microscopy alone, environments for several weeks. because there is no morphologic difference among Invasive form: it can go to different parts of the body; Entamoeba dispar, Entamoeba moshkovskii, and it will not just stay in the intestines. Once it invasive in Entamoeba histolytica (they have the same morphologic the other parts of the body or neighbouring organs, characteristic and appearances). that infection is considered as extraintestinal They can be differentiated using other diagnostic disease. test such as Isoenzyme analysis, polymerase chain reaction, and monoclonal antibody typing. Page | 3 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Morphologic Comparison Between E. histolytica and Ingested RBCs are seen in the trophozoite of E. E. coli histolytica (the only amoebae that have that A. Trophozoite characteristic) If you see other inclusion in the trophozoite, those Point Of E. histolytica E. coli (non- are non-pathogenic amoebae. Differentiation pathogenic) The karyosome of E. histolytica is centrally Movement Unidirectional, Sluggish, non- located, while E. coli is eccentrically located. progressive progressive, and non-directional Shape of Finger-like Blunted pseudopodia Manner or One at a time / Several at a time release of explosive pseudopodia Uninucleate Uninucleate Nucleus (central (Eccentric karyosome) karyosome) Inclusions RBC Bacteria, yeast, debris Cytoplasm Clean looking Dirty looking Size Bigger Smaller (12-60 mm) (15-50 mm) For the Chromatoidal bar, sausage, rod, or cigar- shaped for E. histolytica, and Broomstick, splinter-like for B. CYST E. coli Point of E. histolytica E. coli Differentiation No. of nuclei Quadrinucleate More than 4 Sausage, rod, Broomstick, Chromatoidal cigar-shaped splinter-like bar (rounded ends) (pointed ends) Nuclear Thin Thick membrane Measure of cyst Smaller (10-15 Bigger (10-35 mm) Chromatoidal bar mm) PATHOGENESIS Symptoms E. histolytica causes intestinal and extraintestinal amebiasis. Incubation period is highly variable average ranges from 4 days to 4 months. Amebiasis can be present in different forms and degree of severity depending on the organ affected and the extent of damage caused, also depend on how much parasite you ingested or consumed for it to initiate the infection. Page | 4 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae The typical manifestation of amebiasis is Amoebic PATHOLOGY Dysentery Common associated disease: Intestinal amebiasis, Gradual onset of abdominal pain amoebic colitis, amoebic dysentery, extraintestinal Diarrhea (with or without blood and mucus) amebiasis In children: bloody diarrhea, fever and abdominal pain Abscess formation à Amoebic liver abscess Can cause ulceration “flask-shaped ulcer” in cross- section, with mouth and neck being narrow and base Pathology (Intestinal amebiasis) – does not always is large and rounded, in the intestines (cecum, result in dysentery, it still depends on how much parasite ascending colon and sigmoid) you ingested. Pathogenic determinants / Virulence factors: these Amoebic dysentery Bacillary Dysentery are molecules produced by microorganisms and it can Diarrhea (uncomfortable Can be caused by Shigella, add to the effectiveness to achieve the attachment to belly or growling Salmonella, Campylobacter, cells, immunoinvasion and evasion to immune systems. abdomen) Yersinia, and Enteroinvasive 1. Galactose-inhibitable adherence lectin (Gal Can be differentiated with E. coli Lectin): receptor mediated adherence of amoeba to Bacillary dysentery in target cells. clinical and laboratory 2. Amoeba ionophore: cell lysis and tissue invasion grounds 3. Cysteine proteinase: most important, tissue invading factor Presence of Charcot-Leyden crystals (eosinophils) Ameboma – mass-like lesion; found microscopically in the stool in cases of amoebic painful and can cause dysentery – may indicate that the dysentery is parasitic in abdominal pain; can be seen if you have history of dysentery. nature because eosinophils are present in parasitic infection. Amoebic Bacillary dysentery Dysentery Onset Gradual Acute Extraintestinal amoebiasis Signs / No significant Fever or usually Symptoms fever or vomiting vomiting Through the portal vein (liver), trophozoite reach other Odor of feces Offensive, fishy Odorless parts of the body (liver, brain, lungs, and kidneys). Odor Amoebic hepatitis – this acute hepatic involvement Blood and (+) Often watery and may be due to repeated invasion by amoeba from an mucus bloody active colonic infection or toxic substances that includes trophozoites, from the colon reaching the pH Acidic Alkaline liver. Pus cell / Few Numerous Amoebic liver abscess PMN / o one of the most common extraintestinal forms of Neutrophils amoeba; there’s a presence of liquified necrotic Cellular Scant Massive tissues in the parts of liver. exudates o Cardinal signs: fever, right upper quadrant pain Pyknotic Numerous Few o The abscess or center of the abscess contains a residues thick chocolate-brown pus or anchovy-sauce pus (just like patis) Charcot Present Absent o Metastatic – invaded other parts of the body and Leyden crystals involved the distant organs via hematogenous spread, or through lymphatic. Pathogenic Present Absent o Abscess can be found on the kidneys, brain, amoeba spleen, and the adrenals. Bacteria Few Numerous Amoebic appendicitis and peritonitis Macrophages Absent present Pulmonary amoebiasis Cerebral amoebiasis Splenic abscess Page | 5 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Cutaneous amoebiasis – occurs by direct extension Metronidazole: drug of choice for invasive amebiasis around the anus or colostomy site, or around the (Tinidazole and secnidazole are also effective) discharging sinuses for amoebic abscess. Diloxanide furoate: drug of choice for asymptomatic Genitourinary amoebiasis – prefuse or glands of cyst passers the penis in males during sexual intercourse or can Percutaneous drainage of the liver abscess: be in the vulva, vagina, cervix in females. Patients who do not respond to metronidazole and Asymptomatic carriers: cysts become unnoticed; need prompt relief of severe pain. amoeba reproduce but infected individual shows no Prevention and Control clinical symptoms. Proper hygiene Diagnostic Stage: identification of the cyst or trophozoite Provision for sanitary disposal of human feces Sample for ID: stool (examined within 30 minutes from Improve access to clean and safe drinking water. collection) Good food preparation practices LABORATORY DIAGNOSIS Avoid using “night soil”. Food handler should be examined for cyst carriage. Microscopic detection of the cyst and the Health education and promotion trophozoites in the stool specimen – it serves as the standard method of parasitological diagnosis. NON-PATHOGENIC SPECIES 1. Direct Fecal Smear 1. Entamoeba coli o saline solution: E. histolytica w/ingested RBCs, Harmless inhabitant of the colon trophozoite motility, Charcot Leyden crystals Cysts: Size (10 – 35 microns) o saline + methylene blue: used to differentiate o larger than E. histolytica Entamoeba spp., from the RBCs; Entamoeba o Consists of 8 nuclei with very diffuse karyosome spp. stain blue. o May become hyper nucleated with 16-32 nuclei. o saline + iodine: Check for the nucleus of E. o May also contain needle-like Chromatoidal histolytica to differentiate them from non- bodies with irregular fragmented/sharp/splintered pathogenic amoeba. ends. 2. Concentration Techniques Trophozoites: Size (15-50 microns) o Formalin Ether/ Ethyl Acetate Concentration o Smaller than E. histolytica Technique (FECT) o Has one nucleus containing large, diffuse o Merthiolate Iodine Formalin Concentration karyosome. (MIFC) o Peripheral chromatin is usually dense and 3. Culture: more sensitive than stool microscopy but not irregular. routinely available because of the long incubation o Cytoplasm is usually rough and contain few to period (Ex: Robinson’s and Inoki medium, Boeck and many ingested debris. Drbohlav media, NIH polygenic media, Craig’s medium, and Nelson’s medium Motility Sluggish, not progressive, and non- 4. Serologic Testing: directional o ELISA Pseudopodia Short and blunt; granular; slowly o CIE (counter immune electrophoresis) extruded o AGD (agar gel diffusion) Inclusions Bacteria and other material; no RBCs o IHAT (indirect heme agglutination test) ingested o IFAT (indirect fluorescent antibody test) Nucleus Rarely visible ▪ IHAT and IFAT is considered as the Gold Standard in diagnosing Entamoeba spp. Nuclear Thick; lined with coarse chromatin 5. Molecular Testing: PCR membrane dots and bars Karyosome Large; location is eccentric; In case of your Amoebic liver abscess, we can use surrounded by a halo of non-staining radiography such as Ultrasound, CT-scan, and MRI. material TREATMENT 2. Entamoeba dispar To cure invasive disease at both intestinal and Morphologically similar to E. histolytica, but with extraintestinal site and to eliminate passage of cyst from different DNA and RNA. intestinal lumen. Page | 6 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae 3. Entamoeba hartmanni Similar to E. histolytica except much smaller and no RBC inclusions “Small-race E. histolytica” RBCs from the lesions of the mouth 6. Entamoeba moshkovskii Considered as free-living amoeba. morphologically indistinguishable from those of the disease- causing species E. histolytica and the non- pathogenic E. dispar but differs from them biochemically and genetically. Although sporadic cases of human infection with E. moshkovskii have been reported, the organism is considered primarily a It is quite challenging to identify Entamoeba spp., free-living amoeba. because they are just the same. It takes experience, physiologically unique: osmotolerant, able to grow at practice, and exposure to identify them. Asking patient room temperature and able to survive at 0-41°C. about their history or possible can help us in the 7. Endolimax nana diagnosis. 4. Entamoeba polecki “Smallest amoeba” “Cross eyed cyst” – 4 eccentric nuclei Parasite of the pigs and monkeys (rarely infect Motility Sluggish; random humans) Similar to Entamoeba chattoni: found in apes and Pseudopodia Blunt; hyaline monkeys, identical to E. polecki, identification via Cytoplasm Contain food vacuoles with ingested isoenzyme analysis. bacteria Karyosome Large; central or eccentric in location; irregular outline 5. Entamoeba gingivalis Can be found in the mouth (gum and teeth surfaces) Abundant in cases of oral diseases No cyst stage does not inhabit the intestines, not 8. Iodamoeba butschlii capable of encystation. Transmission through kissing, droplet spray, sharing “Iodine-cyst” because of its affinity to iodine (Iodine- utensils. loving) Large glycogen vacuole/ body which stains deeply with iodine. Page | 7 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Uninucleated – resembling a “basket of flowers” Life Cycle of Acanthamoeba spp. shape. Motility Sluggishly progressive; with hyaline pseudopodia Inclusions Bacteria scattered throughout the cytoplasm; RBCs are never ingested Nucleus Not visible Karyosome Large; centrally located; irregularly rounded; surrounded by a layer of small granules PATHOLOGY Specimen: discharges, exudates, and tissue secretions (because most likely to be affected is the brain or eyes) most suitable specimen is the CSF. Granulomatous Amoebic Encephalitis (GAE) FREE-LIVING PATHOGENIC AMOEBA destructive encephalopathy and associated Acanthamoeba spp. (Acanthamoeba castellani) meningeal irritation (immediate brain involvement) Ubiquitous, free-living ameba (parasitic once entered disease of the immunocompromised (AIDS) the host) Laboratory diagnosis: With an active trophozoite stage with characteristic o made by demonstration of trophozoites and cysts prominent “thorn-like” appendages (acanthopodia) in brain biopsy (post-mortem in most cases), and resilient cyst stage culture, and immunofluorescence microscopy Aquatic organism can survive in contact lens using monoclonal antibodies. cleaning solutions. CSF shows lymphocytic pleocytosis (abnormal Most common ameba of freshwater and soil increase of lymphocytes), slightly elevated protein No flagellate state. levels, and normal or slightly decreased glucose MOT: levels. Aspiration or nasal inhalation: use of contaminated CT scan of brain provides inconclusive findings. swimming pools, deep well, etc. Amoebic keratitis (Contact Lens Users) Direct invasion of the eye: contaminated saline perforation of the cornea and results to subsequent loss of vision Laboratory diagnosis o made by demonstration of the cyst in corneal scrapings by wet mount, histology, culture Thorn-like (growth can be obtained from corneal scrapings appendages inoculated on nutrient agar, overlaid with live or dead Escherichia coli, and incubated at 30°C), demonstration of cyst and trophozoites in stool and PCR. Page | 8 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Naegleria fowleri Life Cycle of Naegleria fowleri Free-living protozoan with two vegetative forms: an ameba (trophozoite form) and a flagellate (swimming form) “Brain-eating amoeba” Thermophilic organism that thrives best in hot springs and other warm aquatic environment True pathogen Incubation period: 2 days to 2 weeks Fetal: fast development and can cause death in an average of 5 days Pathogenesis: *Meningoencephalitis Fatal Primary amoebic encephalitis (PAM) patients initially complain of fever, headache, sore throat, nausea, and vomiting. Hemorrhagic necrosis in postmortem examination of infected brain “Kernig’s sign” - diagnostic sign for meningitis (inflammation within the spaces in the brain) where the patient is unable to fully straighten his or her leg when the hip is flexed at 90 degrees because of hamstring stiffness. MOT: Oral and intranasal routes while swimming in contaminated pools, rivers, and lakes Laboratory diagnosis: CSF examination: o cloudy to purulent o neutrophilic leukocytosis o elevated protein and low glucose o resembling pyogenic meningitis Wet film examination of CSF: (+) trophozoites Autopsy: (+) trophozoites in immunofluorescent staining Culture: can be grown in several kinds of liquid axenic media or non-nutrient agar plates coated with Escherichia coli, (+) both trophozoites and cysts. Molecular Diagnosis: Polymerase chain reaction (PCR) Prevention: o Frequent cleaning o Chlorination o Salination Page | 9 PARA311 1st SEMESTER | intestinal and extraintestinal amoebae Phylum Ciliophora: Ciliates and nitroimidazole have also been reported to be useful Balantidium coli in some cases. Prevention: Causative agent of “balantidiasis or balantidial dysentery”, similar to amoebic dysentery o Avoidance of contamination of food and water Largest protozoan parasite with human or animal feces. Only parasitic ciliate o Prevention of human-pig contact. Primarily associated with pigs—reservoir host o Treatment of infected pigs. Non-invasive o Treatment of individuals shedding B. coli cysts. Morphology: Has trophozoite and cyst stage Parts: o cytostome: entry of food o cytophyge: excretes waste. o Two dissimilar nuclei: are kidney-shaped macronucleus and micronuclei. o One or two contractile vacuoles (They can already be seen in LPO) Pathogenic determinant: o Hyaluronidase: causes the ulceration, secreted by trophozoite o Ulceration is described as flask-shaped ulcer but with rounded base and wider neck. Laboratory diagnosis Specimen: stool o Stool examination: microscopic demonstration of cyst and trophozoite in direct o Biopsy: specimens and scrapings from intestinal ulcers can be examined for presence of trophozoites and cysts. o Culture: can also be cultured in vitro in Locke’s egg albumin medium or NIH polyxenic medium like Entamoeba histolytica, but it is rarely necessary. MOT: ingestion of food/water contaminated with B. coli cyst Infective stage: cyst Treatment: Tetracycline is the Drug of choice. Alternatively, Doxycycline can be given. Metronidazole Page | 10  1ST SEMESTER CLINICAL PARASITOLOGY / LECTURE SY 2023-2024 para311 INTESTINAL AND REPRODUCTIVE ORGAN FLAGELLATES Phylum Sarcomastigophora: Subphylum Mastigophora Possible co-infection with E. vermicularis and A. A. DIGESTIVE AND REPRODUCTIVE FLAGELLATES lumbricoides (LUMEN-DWELLING FLAGELLATES) Chronic infections may mimic irritable bowel syndrome (IBS) Chilomastix mesnili Dientamoeba fragilis Dientamoeba fragilis does not invade the tissues, and Giardia lamblia Trichomonas Tenax the presence produces irritation of the mucosa with Trichomonas hominis Trichomonas vaginalis secretion of excess mucus and hypermotility of the B. BLOOD AND TISSUE FLAGELLATES bowel. (HEMOFLAGELLATES) Diagnosis and Specimen: Leishmania braziliensis Leishmania donovani observation of binucleate trophozoites in multiple fixed Leishmania tropica Trypanosoma cruzi and stained fresh stool or Purge stool. Trypanosoma brucei Purge stool – stool that person force to expel because complex of taking laxative. DIGESTIVE AND REPRODUCTIVE FLAGELLATES Laxative will cause you to expel all the stool, to empty all the stool in your rectum. OTHER INTESTINAL PROTOZOAN Purge stool provides more suitable material for the Dientamoeba fragilis examination than the average form stool. Fixative we can incorporate with the purge stool: No cyst stage identified, only the o PBA fixative trophozoite stage is known. o Schaudinn’s fixative Originally described as an **both permits permanent staining amoeba (based on EM and Treatment: immunologic and molecular phylogenic findings it is actually a flagellate) Iodoquinol (Tetracycline and Resembles Trichomonas Metronidazole are also effective) Despite its name, Dientamoeba fragilis, it is not an Prevention and Control: amoeba but an intestinal flagellate. Most closely, it is Proper sanitation related to Trichomonads. Proper disposal of human waste In human stool specimens, the Dientamoeba fragilis is almost always found solely as a trophozoite because it BASIC STRUCTURE OF FLAGELLATES is not capable of encystation. 1. Flagellum/Flagella – locomotor apparatus Morphology of the Trophozoite: 2. Kinetoplast – provides energy a) Blepharoplast Rosette shaped nuclei (1 to 2) b) parabasal body o Can be mononucleated or binucleated. 3. Cytostome – cell mouth o Rosette – “flower-form” 4. Undulating membrane – a membrane laterally Cytoplasm may contain vacuoles with ingested projecting from the body of certain flagellates, participate debris. in active motility of the flagella Shows progressive motility. 5. Axostyle or axial rod – for support in locomotion Broad hyaline pseudopodia that possess characteristic 6. Costa – rib-like structure within the cytostome for “serrated margin”. support MOT: **Undulating membrane, Axostyle, and Costa are Fecal-oral route used to support the locomotion of the parasite via transmission of helminth eggs (e.g., Enterobius vermicularis) It has been observed that, some of Dientamoeba fragilis are found in the lumen of Enterobius vermicularis adults. There can be a co-infection between Dientamoeba fragilis and Enterobius vermicularis, as well as Ascaris lumbricoides. Pathogenesis: Infections are asymptomatic. Page | 1 BACT211 LEC 2nd SEMESTER | TOPIC TITLE A. PATHOGENIC Giardia lamblia Cercomonas intestinalis: Initial name (Dr. F. Lambl) Giardia lamblia: (by Stiles→Dr. Giard and Dr. Lambl) Giardia intestinalis: synonymous to Giardia duodenalis Other name: Lamblia duodenalis or L. intestinalis **for the sake of the examination, we will use the name Giardia lamblia Habitat: duodenum, jejunum, and upper ileum of humans Morphology A. Trophozoite: “Old-man with eyeglasses”, “Monkey Face” pear/tear drop shaped, pyriform, shape of a tennis racket. Bilaterally symmetrical with large ventral sucking disc (used to attach in the intestinal wall) – pathogenic determinant. 4 pairs of flagella, 2 ventral sucking discs 2 ovoidal nuclei with distinct karyosome (symmetrically bilateral) “Falling leaf motility” – movement. Life Cycle of Giardia Lamblia Covered with variant-specific surface proteins (VSPs) – are not fully-elucidated but it suggests resistance to intestinal proteases or intestinal enzymes attributing to the survival of the parasites. B. Cyst Ovoidal in shape Thick shell (double wall), surrounded by a hyaline cyst wall. Classified based on the Nuclei: o 2 (Immature), 4 (mature) Presence of Axostyle Infective stage: Mature cysts o It can be able to survive the environment because it is surrounded by a hyaline cyst wall just like the cyst of Entamoeba histolytica, making the cyst as the infective cyst. resistant to routine chlorination MOT: Giardia lamblia is an obligate parasite since it has only Ingestion of contaminated food and water with G. lamblia one host, which is human. mature cyst Infective stage will be the mature cyst—we can get that if we drink or ingested a contaminated food and water or a direct contact through fomites with the infective cyst. Once a mature cyst is ingested, they pass safely to the stomach and undergo excystation in the duodenum in about 30 minutes, developing into a trophozoites. Page | 2 BACT211 LEC 2nd SEMESTER | TOPIC TITLE And those trophozoites will rapidly multiply via binary Diagnosis fission and they will attach to the intestinal villi causing Specimen: Stool (where trophozoite and cyst usually shed) pathologic changes. and Duodenal contents The trophozoites may be found in the jejunum and once the feces enter and dehydrates, they will undergo Diagnostic Stage: Trophozoite and Cyst encystation, the one shedding in the feces is the Lab Tests: matured cyst. Direct Fecal Smear – when we prepare a wet-mount, The trophozoites are also pass in the stool but they do we can observe the floating or the falling leaf-like motility not survive in the environment, because generally, of Giardia lamblia. trophozoites are fragile. Concentration techniques Pathogenicity o we can incorporate during light infection and directly we can aspirate jejunum-duodenal content. The examination of the duodenal contents or trophozoites, we can have a higher percentage of positive findings since it’s the intestinal content that we are analysing. o We can use this method to aspirate the jejunum- duodenal content. Entero test / Enterotube test / string test / Beale String’s test (non-invasive) o It is a non-invasive procedure where the patient swallow’s gelatine capsule (with sponge inside) The parasite attaches to the intestinal cells via adhesive attached to a nylon string with one end of the string sucking disc located in the large ventral sucking disc, attached to the patient’s cheek and after 4 to 6 causing mechanical irritation on the affected tissue. hours, any adherent fluid on the sponge will be it produces lectin for attachment. subjected to microscopic examination. And the organism is able to avoid peristalsis (movement Aspirate and Biopsy (invasive) of the GIT) by trapping itself between villi or in the Other tests: intestinal mucus. Intestinal villi are important in the absorption of nutrient Antigen detection test and Immunofluorescent from the food we are eating. commercial test kit In the case of Giardia lamblia infection, there is a o where we can detect the antigen in the stool flattened intestinal villus meaning there is a problem o the antigen we are detecting is called Cyst wall with the absorption. protein 1. If there is villus flattening and crypt hypertrophy, it can Direct fluorescence antibody test – considered as the lead to decrease glucose, decrease electrolytes and “Gold standard” because it has a high sensitivity and fluid absorption. specificity in testing. Generally, it causes small absorption and maldigestion (since it mechanically disrupts the intestinal villi) Pathology causative agent of Giardiasis or Lambliasis o If you ingested the mature trophozoites, within 1 to 4 weeks or an average of 9 days and half of the patients are asymptomatic. “Traveller’s diarrhea” - St. Petersburg, Russia (first recorded water outbreak and involved a group of visiting travellers) o Other names: Gay bowel syndrome; Failure to thrive Treatment: syndrome. Drug of Choice: Metronidazole (3x a day of 1 week) Onset of pathology:1 to 4 weeks and in an average of 9 Alternatives: Tinidazole, Albendazole, Furazolidone, days. Quinacrine and Paromomycin Half of the patients are asymptomatic. Acute infections: “rotten eggs” odor (because of the Prevention and Control presence of hydrogen sulfide) Proper disposal of human excreta Chronic infections: steatorrhea (malabsorption of fats) - Improve access to clean and safe drinking water. passage of greasy, frothy stools that may float on toilet water. Page | 3 BACT211 LEC 2nd SEMESTER | TOPIC TITLE o Proper water treatment that includes combination of MOT: - Sexual intercourse chemical therapy and filtration, because the cyst is Can be passed through newborns through the birth resistant to routine chlorination canal. Good food preparation practices. Contaminated underwear or towels or sitting at Avoid using “night soil”. contaminated toilet bowl—but least likely because Health education and promotion. trophozoite eventually die due to the environment. Trichomonas vaginalis **Trichomonas vaginalis infection is the most prevalent The only pathogenic Trichomonas non-viral sexually-transmitted infection No cyst stage (They are in trophozoite form only) Trichomoniasis often co-existing with Habitat: Urogenital tract other sexually-transmitted diseases like o Female: vulva (vagina) (pH 5.2-6.4) candidiasis, gonorrhoea, syphilis, and o Male: prostate gland HIV** Morphology of the trophozoite caused by Candida albicans (candidiasis), sa mycv naman 'to pag-aaralan Specimen: Pyriform shape Male: urine sample, prostatic fluid, or 4 free anterior flagella seminal fluid o 5th flagellum is embedded in the undulating Female: urine sample, vaginal discharge, cervical membrane. scrapings Prominent Axostyle and single nucleus Laboratory Tests: Presence of undulating membrane – used to support the motility. A. Microscopy “Rapid jerky tumbling” or “twitching” o wet smear or wet mount (saline preparation – fast and most inexpensive way of diagnosis but the **In the wet mount preparation, the morphology is not sensitivity is low up to 60-70% because of the fully preserved. In some cases, Trichomonas vaginalis can contamination that may interfere with the only be a contamination of the urine. It can be seen in the morphology of the trophozoites) urine sample because the vaginal secretion goes along o Fixed and stained wet drop: Giemsa, during urination, that may disrupt the morphology of the Papanicolaou, Romanowsky and Acridine Orange trophozoite because of the vaginal fluid. B. Culture – “Gold Standard”; we must culture it for 2 to Infective and Diagnostic stage: Trophozoite 5 days and it grows best at 35 to 37C under anaerobic Pathology conditions and the optimal pH is between 5.5 to 6 (acidic) Correlates only to the number of sexual partners o Feinberg-Whittington medium o Male: carrier o Diamond Modified medium. o Female: reservoir o Trypticase Luver Serum medium Trichomoniasis o InPouch TV Test- novel transport and culture Persistent urethritis, persistent vaginitis, infant system (sealed pouch with culture media) – you just infections—especially if the mother give birth normally, get a swab sample and then you will put it inside the so it can be pass to the newborns through birth canal. pouch containing the fluid or culture media inside, Onset: 4 to 28 days after the inoculation of the viable and then after incubation days, you can already Trichomonas vaginalis trophozoite and they are observe under the microscope. proliferating in the target cells, and they cause the Treatment degeneration and squamation of the vaginal epithelium followed by leukocytic inflammation of the tissue layers Oral Metronidazole (Tinidazole) - chemotherapy Acidic Douche (10% vinegar) – used as feminine Symptoms wash to alleviate the itching and the burning sensation. Males: asymptomatic (less persistent, self-limiting) Prevention and Control: Females: o Greenish-yellow discharge Both the male and female must be treated ▪ because Trichomonas vaginalis particularly o Why males should also be treated? Because infects the squamous epithelium or the lining even though they are asymptomatic, but they can of the vagina) actually transmit the parasite once they have sexual ▪ It secretes cysteine proteases, lactic acid, intercourse with the other. acetic acid which disrupt the glycogen levels 4 Cs (Counselling, Compliance, Contact Tracing, and lower the pH of the vaginal fluids. Correct and Consistent use of Condom) o Edema, itching, burning sensation. Case Finding o “Strawberry cervix” Choice and number of sexual partners Page | 4 BACT211 LEC 2nd SEMESTER | TOPIC TITLE ABSTINENCE MORPHOLOGIC COMPARISON OF THE TROPHOZOITE Point of Giardia lamblia Trichomonas Comparison vaginalis Shape Pear, tear-drop, Pyriform pyriform Characteristic Round anterior, Prominent pointed posterior, axostyle, with large sucking undulating disc membrane Flagella 4 pairs (anterior, mid, sucking disc, Trichomonas hominis 4 anterior extreme posterior) Usually found in cecal area of Nuclei 2 nuclei Uninucleated large intestine Symmetry Symmetrical Asymmetrical Commensal occurs only in trophozoite. Motility Falling-leaf Rapid jerky Pyriform shape tumbling 5 anterior flagella and a posterior Pathogenicity Pathogenic Pathogenic flagellum Relatively smaller than T. vaginalis MORPHOLOGIC COMPARISON OF THE CYST Trichomonas tenax Point of Giardia lamblia Trichomonas Comparison vaginalis Usually found in the mouth Shape Ovoid living in tartar around teeth and cavities of carious teeth, occurs Characteristic Thick shell, Axostyle NO CYST only in trophozoite present STAGE Pyriform shape Nuclei 2 to 4 smaller and slender than T. vaginalis B. NON-PATHOGENIC ATRIAL FLAGELLATES 4 free equal flagella and a 5th one on the margin of the Chilomastix mesnili undulating membrane **Trichomonas vaginalis – urine/vaginal fluids largest flagellate in man **Trichomonas hominis – stool Trophozoite **Trichomonas tenax - mouth Asymmetrical Enteromonas hominis Pear-shaped Spiral groove on midportion Demonstrates “jerky motility”. 3 anterior flagella Very small like Endolimax nana 1 flagellum within the cytostome → Cystostomal fibril (shepherds crook, safety pin appearance) “Boring/spiral movement or Cork- bird beak screw movement” Retortamonas intestinalis Cyst Pear or lemon shaped Demonstrates “jerky motility”, 2 anterior flagella. Conical anterior with knob-like or “nipple-shaped” Stained stool preparation is the best sample to protuberance examine its presence. Page | 5 BACT211 LEC 2nd SEMESTER | TOPIC TITLE Page | 6  1ST SEMESTER CLINICAL PARASITOLOGY / LECTURE SY 2023-2024 para311 BLOOD AND TISSUE FLAGELLATES Phylum Sarcomastigophora: Subphylum Mastigophora 1. Amastigote (“A- “means absent) HEMOFLAGELLATES (Arthropod borne) - No flagellum - round, ovoid A. Leishmania spp. B. Trypanosoma spp. - usually found in small groups of cyst-like collection Leishmania tropica Trypanosoma in tissues gambiense - Intracellular parasites; multiply through binary Leishmania braziliensis fission inside the host’s tissues or cells Leishmania donovani Trypanosoma 2. Promastigote rhodesiense - Elongate parasite with a flagellum and its Trypanosoma cruzi kinetoplast is still in the posterior part. Arthropod-borne – transmitted through insect- - lanceolate bites; these vectors are biological vectors because they are 3. Epimastigote involved in the life cycle of the parasite. - Elongated - Kinetoplast is posterior but cannot pass the Infection / cases of Blood and Tissue Flagellates nucleus. have not yet been documented in the Philippines. But - Undulating membrane appears. possibly in the future, we can have a case because of easy 4. Trypomastigote migration, and the most important reason is that the vectors - Elongated, spindle shape. (insects) of these parasites are found in the Philippines. - Long slender or short stumpy GENERAL CHARACTERISTICS - C, U, S-shaped; Kinetoplast completely pass the They live in the blood and nucleus. tissues of man and other - Manifest in our circulation (in blood) vertebrate hosts and in the gut of the insect vectors. Members of this family have a single nucleus, a kinetoplast, and a single flagellum. Nucleus is round or oval and is situated in the