Week 7 - Blood and Tissue Flagellates PDF

PARA311 – MIDTERMS Transcribed by: Shane Maurine E. Siscar WEEK 7: BLOOD AND TISSUE FLAGELLATES HEMOFLAGELLATES Amastigotes Promastigote...

PARA311 – MIDTERMS Transcribed by: Shane Maurine E. Siscar WEEK 7: BLOOD AND TISSUE FLAGELLATES HEMOFLAGELLATES Amastigotes Promastigote 5 by 3 μm 9-15 μm long ✓ This are parasites which inhabits the tissue and the blood of human with theaid of vectors. Round to oval Long and slender One nucleus, usually off One nucleus, located in or Member species center near center ✓ Leishmania spp. Kinetoplast present, consisting ✓ Kinetoplast, located in of dotlike blepharoplast from anterior end. ✓ Trypanosoma brucei gambiense which emerges a small ✓ Single free flagellum, ✓ Trypanosoma brucei rhodesiense axoneme. extending from ✓ Trypanosoma cruzi Parabasal body located anterior end usually an adjacent to the blepharoplast extracellular phase as nonflagellate, intracellular also in the insect called Leishman-Donovan (LD) intermediate host (or bodies in human cells. in culture) of leishmania parasites. Epimastigote Trypomastigote 9-15 μm long 12-35 μm long by 2-4 μm wide Long and slightly wider C, S or U shape often seen in than promastigote form stained blood films One nucleus, located in One nucleus, located posterior end anterior to the kinetoplast ✓ Kinetoplast located ✓ Kinetoplast located in anterior to the the posterior end nucleus. ✓ Undulating STRUCTURAL PARTS ✓ Undulating membrane, extending membrane, extending entire body length Blepharoplast half of body length ✓ Free flagellum, - basal body in certain flagellated protozoans that ✓ Free flagellum, extending from consists of a minute mass of chromatin extending from anterior end when anterior end found in present only stage embedded in the cytoplasm at the base of the the intestine of the found in man in the flagellum. vectors latter illness. Kinetoplast Trypanosoma cruzi - is a disk-shaped mass of circular DNAs inside a - Disease: Chagas disease or American large mitochondrion that contains many copies Trypanosomiasis of the mitochondrial genome - Carlos Chagas: found trypanosome on the intestine of a triatomid bug were the same Undulating membrane parasite found in a child suffering from fever and - a locomotory organelle of certain flagellate enlargement of lymph nodes. (trypanosome and trichomonad) parasites, - An intracellular parasite consisting of a finlike extension of the limiting - Exhibits all four stages of development: membrane with the flagellar sheath; wavelike amastigote, promastigote, epimastigote, rippling of the undulating membrane produces a trypomastigote characteristic movement. BIOLOGICAL VECTOR STAGE OF DEVELOPMENT Amastigote Promastigote Epimastigote Trypomastigote  LIFE CYCLE o Indeterminate Phase - 10-30 years of latency - relatively asymptomatic with no detectable parasitemia - seropositive o Chronic Phase - 10-30% of infected exhibit cardio- myopathy or megasyndromes ACUTE PHASE FEATURES 1–2-week incubation period local inflammation MODES OF TRANSMISSION - Romaña’s sign: edema of the eyelid and conjunctiva Source - Chagoma: inflammation at the site of inoculation natural transmission by symptoms can include: fever, malaise, Vector triatomine bugs through blood lymphadenopathy, hepatosplenomegaly, meal/contamination with nausea, diarrhea infected feces acute, often fatal, myocarditis develops in a few a prevalent mode of individuals Transfusion transmission in urban area. - high parasitemia’s in myofibrils Gentian violet (24hr) eliminates parasite in blood occurs during any stage of T. Congenital cruzi infection. Can result in premature labor, abortion or neonatal defects Accidental ingestion of food contaminated with metacyclic trypomastigotes TYPES OF BIOLOGIC VECTOR Chronic Chagas' Cardiomyopathy Salivarian Stercoralian long latency characterized by seropositivity and transmission via mouth hind gut station: acquired no parasitemia parts from feces or eating the higher prevalence of ECG abnormalities in vector asymptomatic seropositive persons very efficient inefficient progressive development of abnormalities o right bundle branch block o left anterior hemiblock infection rate in vector is infection rate clinical presentations include: low o arrhythmias and conduction defects o congestive heart failure o thromboembolic phenomenon PATHOLOGY cardiomegaly apical aneurysm (left ventricle) PATHOGENESIS extensive fibrosis* hypertrophy* o Acute Phase +- cellular infiltration - active infection *correlates best with cardiac symptoms - 1-4 months duration - most are asymptomatic (children most likely to be symptomatic)  AMASTIGOTES OF TRYPANOSOMA CRUZI PREVENTION AND CONTROL ✓ improvement of human dwellings ✓ separation of animal stalls from house ✓ health education ✓ insecticides o synthetic pyrethroids ✓ gentian violet in blood for transfusions TREATMENT Pseudocyst in a section of heart muscle acute stage Note necrosis in upper right corner. o nifurtimox (8-16 mg/kg/day, 60- 90days) o benznidazole (5-7 mg/kg/day, 30-120 days) o allopurinol (experimental) o azole antifungal agents (experimental) chronic stage o treat symptoms CLINICAL MANIFESTATION Spleen smear Note the absence of an undulating membrane or Gambian emergent flagellum, the kinetoplast (K) is more trypanosomiasis – darkly stained than the nucleus (N), and the Winterbottom’s parasite’s cytoplasm is unstained sign (enlarged, Amastigotes of T. cruzi would be non-tender indistinguishable from those of L. donovoni posterior cervical lymph nodes with DIAGNOSIS a consistency of history of living in infested house ripe plums. bug bite, chagoma, Romaña's sign cardiac or gastro-intestinal symptoms o imaging detection of parasite (acute stage) serology (chronic stage) Leishmania spp. parasite detection o direct examination Leishmania have two morphological forms: o stained blood smears a) amastigote o inoculation into mice b) promastigote o in vitro culture o xenodiagnosis - allow triatomine bugs Causative agent Disease to feed on patient and look 10-30 days later for flagellates Leishmania tropica Baghdad boils, Oriental o PCR sore serological tests Leishmania mexicana Bay sore, Chiclero ulcer o hemagglutination Leishmania donovani Dum dum fever, Kala-azar o immunofluorescence o ELISA Leishmania braziliensis Espundia, Uta o complement fixation Leishmania guyanensis Forest yaws, Pian bois Trypomastigotes; blood smear Free flagellum, moderately long undulating membrane Posterior location of larger size of the kinetoplast (K) Characteristic “C”-shape of several cells  Promastigote Amastigotes PATHOGENESIS The multiplying amastigotes inside phagocytes cause destruction of the host cells. Macrophages with amastigote forms in their cytoplasm are set free in the circulation, i.e from the skin to the viscera. Amastigotes are released and are taken-up by the fixed macrophages in the spleen, liver, bone marrow, and other centers of reticuloendothelial activity. The host cellular defense is stimulated resulting to proliferation of macrophages in infective to humans Lives intracellularly in the bone marrow, which comprises the monocytes, production of red cells and granulocytes. polymorphonuclear The end-effects are granulocytopenia and leukocytes and anemia. endothelial cells of the The spleen, liver and lymph nodes are vertebrate host. enlarged whereby the spleen may end up into have single free flagellum hypersplenism that causes more arising from kinetoplast at destruction of the red blood cells. the anterior end The host immune reaction is also stimulated promastigote in the resulting to increase production of globulin proboscis of the insect that may result to reversal of the albumin- vector and the one that globulin ratio. grow in artificial media. The infection is therefore, regarded as a form of “reticuloendotheliosis”. LIFE CYCLE OF LEISHMANIA TYPES OF LEISHMANIASIS Type Pathogen Location Cutaneous The most Cutaneous leishmaniasis common is the infections are (localized and Oriental Sore most common in diffuse) infections (caused by Afghanistan, appear as obvious species L. Brazil, Iran, Peru, skin reactions. major, L. tropica, Saudi Arabia and and L. Syria. aethiopica, L. mexicana.) Mucocutaneous TRANSMISSION leishmaniasis Mucocutaneous The reservoir hosts are rodents, dogs, foxes and (espundia) infections are jackals infections will start L. braziliensis most common in off as a reaction at Bolivia, Brazil and The infection is usually transmitted by the bite the bite, and can go Peru, in Karamay, (blood feed) of the female sandfly, genus via metastasis into China Xinjiang Phlebotomus and Lutzomyia the mucous Uygur Human infection has been reported from blood membrane and Autonomous transfusion, congenital transmission, become fatal. Region. contamination of bite wounds and by contact. Visceral Found in tropical leishmaniasis Caused and subtropical Leishmania mexicana infections exclusively by areas of all are often recognized species of continents except by fever, the L. Australia. Visceral swelling of the liver donovani infections are most and spleen, and complex (L. common in anemia. They are donovani, L. Bangladesh, Brazil, known by many local infantum syn. India, Nepal and names, Dum Dum L. Sudan, in part of Fever, Death Fever chagasi). China, such as Disease: New World cutaneous leishmaniasis, and Kala azar. Province and chiclero ulcer, bay sore Xinjiang Uygur Autonomous North Central America, Mexico, Texas and Region. possibly the Dominican Republic and Trinidad Cutaneous form, increasing in numbers of CLINICAL TYPES OF CUTANEOUS LEISHMANIASIS infected main reservoir are rodents Leishmania major 3 clinical manifestations: - found in sparsely inhabited areas o Cutaneous - Zoonotic cutaneous leishmaniasis o Chiclero-ulcer - Wet lesions with severe reaction o Nasopharyngeal mucosal – rare - rapid ulceration; few amastigotes manifestation o Visceral – rare manifestation Leishmania tropica - found in more densely populated regions UNCOMMON TYPES - Anthroponotic cutaneous leishmaniasis - Dry lesions with minimal ulceration ✓ Leishmania aethiopica - Many amastigotes; persists for months - Diffuse cutaneous leishmaniasis (DCL): Cutaneous leishmaniasis caused by, diffuse nodular non-ulcerating lesions. - Low immunity to Leishmania antigens (anergic), numerous parasites. ✓ Leishmaniasis recidiva - lupoid leishmaniasis: severe immunological reaction to leishmania antigen leading to persistent dry skin lesions, Leishmania tropica few parasites. ✓ Disease: cutaneous leishmaniasis, Old World Leishmania braziliensis cutaneous leishmaniasis, oriental Causes espundia, uta or mucotaneous/ american leishmaniasis sores, Delhi boils, Found in Central Mexico and Northern Argentina Baghdad boils, dry or Find LD bodies in tissues urban cutaneous leishmaniasis. Once cured, lifelong immunity; if dormant – may re-occur ✓ incubation period: 2 weeks to several months Mucocutaneous Leishmaniasis ✓ skin ulcer: ✓ Has a clinical picture dominated by great elevated destruction of the nasal mucosa, sometimes with and respiratory complications indurated ✓ Mucocutaneous leishmaniasis is the most feared ✓ lesions are form of leishmaniasis because it produces painless but destructive and disfiguring lesions of the face with subcutaneous nodules. (Tapir nose) ✓ Espundia: metastatic spread to the oronasal and pharyngeal mucosa  Untreated disease can be fatal. After recovery it might produce a condition called post-kala-azar dermal leishmaniasis (PKDL) that resembles histoid type of leprosy. DIAGNOSIS DIAGNOSIS: CUTANEOUS AND MUCOCUTANEOUS LEISHMANIASIS Diagnosis: Smear: Giemsa stain – microscopy for LD bodies Microscopy (amastigote) or culture in NNN (amastigotes) medium of the following specimen: o Bone marrow aspirate Biopsy: microscopy for LD o Splenic aspirate bodies or culture in NNN o Lymph node medium for promastigotes o Tissue biopsy Serologic techniques: IFA Specific serologic tests: Direct Agglutination Montenegro intradermal Test (DAT), ELISA, IFAT, Complement fixation reaction test - highly specific and of Skin test (leishmanin test) for survey of great use in cutaneous leishmaniasis, populations and follow-up after treatment. although the test may be negative in the Non-specific detection of hypergammaglobulin disseminated form. by formaldehyde (formol-gel) test or by - Cellular immunity depends on T- electrophoresis. lymphocytes and becomes positive 24-48 Antibody titers hours after infection. - low in cutaneous, high in mucocutaneous and very high in disseminated cutaneous or Leishmania donovani visceral leishmaniasis. Disease: Visceral leishmaniasis, kala-azar, PREVENTION AND CONTROL dum dum fever ✓ improvement of human dwellings There are geographical variations. ✓ separation of animal stalls from house ✓ health education Leishmania infantum mainly affect children ✓ insecticides Leishmania donovani mainly affects adults ✓ synthetic pyrethroids ✓ gentian violet in blood for transfusions CLINICAL MANIFESTATION TREATMENT Fever: twice daily elevations Similar medications used for leishmanisis but modes of administration and dosages Splenomegaly, may vary. hepatomegaly, hepatosplenomegaly First-line therapy (Antimonials): SbV, Pentavalent antimonials include sodium Weight loss stibogluconate and methylglucamine Anemia antimonite. Epistaxis Second line therapy: Amphotericin B, Cough pentamidine (for kala-azar), metronidazole, Diarrhea nifurtimox. Loss of weight o Liposomal AMB (L-AMB) is less toxic Lymphadenopathy than AMB. It has been effective in the pancytopenia primary treatment of VL in both Hypergammaglobinemia immunocompetent and darkening of the skin immunocompromised patients.  Trypanosoma brucei gambiense o Kerandel’s sign: CNS invasion, more Trypanosoma brucei rhodesiense severe headache, increased mental dullness and apathy, tremors, hyperesthesia Trypanosoma brucei Disease: Human African Trypanosomiasis Rhodesian It is caused by two subspecies of Trypanosoma trypanosomiasis brucei, namely: o more - Trypanosoma brucei rhodesiense: East rapid and Africa, wild and domestic animal reservoirs, fatal East African/Rhodesian sleeping sickness - Trypanosoma brucei gambiense: West and DIAGNOSIS Central Africa, mainly human infection, West African/Gambian sleeping sickness forms exhibited: epimastigote, trypomastigote LIFE CYCLE Demonstration of trypomastigotes in the Giemsa-stained blood, lymph node aspirate and CSF Serologic techniques: indirect hemagglutination, ELISA, immunofluorescence Thick and thin blood films Buffy coat concentration method TRANSMISSION Trypanosoma brucei Trypanosoma brucei Through the bite of the tsetse gambiense rhodesiense fly (Glossina spp.), the metacyclic trypomastigotes will be inoculated to the blood of the host - Glossina tachinoides - Glossina palpalis CLINICAL MANIFESTATION Earliest sign is the indistinguishable from one indistinguishable from one chancre (painful lesion at another another the site of inoculation) TREATMENT Acute stage – irregular fever, headache, myalgia, Effective when begun early in the course of the tachycardia, dizziness and disease (blood-lymphatic stage) rash (episodic, 1-6 days Pentamidine and suramin followed by an Melarsoprol or tryparsamide (late stage-CSF) asymptomatic period lasting several weeks) DL-alpha-diflouoromethylornithine (DFMO, Eflornithine): ornithine decarboxylase inhibitor Gambian trypanosomiasis o Eflornithine: not very effective against o Winterbottom’s Rhodesian sleeping sickness sign: enlarged, non-tender PREVENTION AND CONTROL posterior Reduction of contact with tsetse flies cervical lymph - Traps, screen, insecticides nodes with a Diagnosis and treatment of infected individuals consistency of Tsetse belt: endemic area extending over third ripe plums of Africa o