Parasitology for Technologists (1) TL 202 PDF

Department of Microbiology & Immunology Parasitology for technologists (1) TL 202 By Dr. Selwan Hamed Aboelnaga PhD In Pharmaceutical Sciences (Microbiology & Immunology) From Faculty of Pharmacy - Helwan University and UIU...

Department of Microbiology & Immunology Parasitology for technologists (1) TL 202 By Dr. Selwan Hamed Aboelnaga PhD In Pharmaceutical Sciences (Microbiology & Immunology) From Faculty of Pharmacy - Helwan University and UIUC (University of Illinois at Urbana-Champaign) – Illinois – USA 1) Protozoa  Protozoa 2) According to site of infection: They could be classified into : A) Intestinal –urogenital protozoa. B) Blood and tissue protozoa. Parasite name: Entamoeba histolytica Parasite name: Entamoeba histolytica Type: Intestinal protozoa Infective stage: cyst Symptoms: abdominal pain, cramping, and colitis with diarrhea, amoebic dysentery. Diagnostic stage: trophozoite,cyst Definitive host: human Intermediate host: None Sample type: Stool, scanning for amoebic hepatitis, serology. Treatment: Rehydration, Metronidazole.  A) Intestinal –urogenital protozoa. 2-Flagellates The flagellates of clinical significance include: Giardia duodenalis and Trichomonas vaginalis. Giardia has both cyst and trophozoite stages in its life cycle. In contrast, no cyst stage has been observed for Trichomonas.  1) Giardia duodenalis (G. lamblia; G. intestinalis) Giardiasis Life cycle  Clinical syndrome 1. Giardia infection can result in either asymptomatic carriage or symptomatic disease. 2. The incubation period before symptomatic disease develops ranges from 1 to 4 weeks (average 10 days). Malabsorption syndrome:‫سوء امتصاص‬ 1) Malabsorption of fats: 2) a- Malabsorption is characterized by weight loss, fatigue and fatty stools (steatorrhoea). This results in accumulation of unabsorbed fatty acids in the intestines giving the stools the pale yellow frothy appearance (lentil soup). 2- Malabsorption of vitamin B12  Clinical syndrome 2. Chronic Carrier: In many cases, the trophozoites remain confined to the intestinal lumen (noninvasive infection) of individuals who are asymptomatic carriers, passing cysts in their stool.  Laboratory Diagnosis 1. With the onset of diarrhea and abdominal discomfort, stool specimens should be examined for cysts and trophozoites. 2. One stool specimen per day for 3 days should be examined.  Laboratory Diagnosis 3. Several immunological tests for detection of antigen are available commercially.  Treatment 1. It is important to eradicate Giardia from both asymptomatic carriers and diseased patients. 2. Effective treatments include metronidazole, tinidazole, and nitazoxanide. Parasite name: Giardia duodenalis Type: Intestinal protozoa Infective stage: cyst Symptoms: abdominal pain, cramping, steatorrhoea, lentil soup diarrhea. Diagnostic stage: trophozoite, cyst Definitive host: human Intermediate host: None Sample type: Stool Treatment: Rehydration, Metronidazole.  Trichomonas vaginalis 1. Trichomonas vaginalis is not an intestinal protozoan but rather the cause of urogenital infections. 2. T. vaginalis exists only as a trophozoite, oval in shape with four flagella and a short undulating membrane that are responsible for motility.  Trichomonas vaginalis 1.It is found in the urethras and vaginas of women and the urethras and prostate glands of men. 2.The acidity of the normal vagina (pH 4.0-4.5) usually discourages infection, but once established the parasite causes a shift towards alkalinity (pH 5.0-6.0) which encourages further parasitic growth.  Life cycle Sexual intercourse is the primary mode of transmission.  Clinical Syndromes 1.Women: Vaginitis may occur with more extensive inflammation and erosion of the epithelial lining, associated with itching, burning, and painful urination. 2.Men are primarily asymptomatic carriers who serve as a reservoir for infections in women. 3.However, men occasionally experience urethritis, prostatitis, and other urinary tract problems. Laboratory Diagnosis: The microscopic examination of vaginal or urethral discharge for characteristic trophozoites is the diagnostic method of choice. Treatment: Recommended regimen Metronidazole Or Tinidazole Both Partners should be treated Parasite name: Trichomonas vaginalis Type: urogenital protozoa Infective stage: trophozoite Symptoms: Vaginitis, urethritis., vaginal discharge. Diagnostic stage: trophozoite. Definitive host: human Intermediate host: None Sample type: Vaginal swab/discharge. Treatment: Metronidazole (both partners should be treated).  Ciliates The intestinal protozoan Balantidium coli is the only member of the ciliate group that is pathogenic for humans.  Swine and (less commonly) monkeys are the most important reservoirs. Infections are transmitted by the fecal-oral route; out-breaks are associated with contamination of water supplies with pig feces. Life cycle & pathogenesis  Clinical Syndromes 1.As with other protozoan parasites, asymptomatic carriage of B. coli can exist. 2.Symptomatic disease is characterized by abdominal pain and tenderness, nausea, anorexia, and watery stools with blood and pus. 3.Extraintestinal invasion of other organisms is extremely rare in balantidiasis. Laboratory Diagnosis Microscopic examination of feces for trophozoites and cysts is performed. Treatment, Prevention, and Control The drug of choice is tetracycline and metronidazole Thanks