Clinical Parasitology LAB PDF 2024-2025

LESSON #1: INTRODUCTION TO MEDICAL PARASITOLOGY BSML-2211 2nd SEMESTER | ACADEMIC YEAR: 2024-2025 |JOHN DARYLL NACUA PARASITE-HOST RELATIONSHIP P...

LESSON #1: INTRODUCTION TO MEDICAL PARASITOLOGY BSML-2211 2nd SEMESTER | ACADEMIC YEAR: 2024-2025 |JOHN DARYLL NACUA PARASITE-HOST RELATIONSHIP PARASITOLOGY ​ It refers to the study of parasites. ​ We study how parasites are transmitted, their life cycles, their relationship with the host, and how they cause diseases. Parasite An organism that lives on and obtains their nutrients from another organism. MODE OF PARASITE TRANSMISSION PARASITIC LIFE CYCLES Three common components: Mode of Transmission Morphologic Forms Invades humans, known as the infective stage. Diagnostic Stage Can be detected via laboratory retrieval methods. LESSON #1 (BSML-2211) Clinical Parasitology - LAB Lorin Sophia S. Itaralde  Laboratory Diagnosis DISEASE AND SYMPTOMS Based significantly on laboratory reports or test results. ​ Important procedure in: ○​ Evaluating a disease by providing evidence to a new or unsuspected etiologic agent. ○​ Confirming a clinical impression that the condition has parasitic nature. ○​ Aid physician for the appropriate medication. ○​ Help in monitoring the effect of a treatment regimen. ​ Accurate and reliable results depend on: ○​ Proper specimen collection ○​ Specimen handling ○​ Specimen processing ○​ The examiner's skills TREATMENT ○​ The quality of the specimen used ​ Crucial step to successful parasite recovery. ​ The most commonly submitted specimens: ○​ Stool and blood (examined macro and microscopically using the O&P recovery method). ○​ Other specimens include blood, tissue biopsies, CSF, sputum, urine, and genital material. PREVENTION AND CONTROL SPECIMEN FOR PARASITIC EXAMINATION Fecal Specimen ​ Common for intestinal parasites. ​ Demonstrates eggs, larvae, adults, trophozoites, cysts, and oocysts. DIAGNOSING PARASITIC INFECTION ​ Can be used for immunological tests. ​ Must be collected and placed in a clean, Clinical Diagnosis wide-mouth container made with waxed cardboard, plastic or glass with a tight-fitting Physical examination; based on signs and lid. symptoms of the patients. LESSON #1 (BSML-2211) Clinical Parasitology - LAB Lorin Sophia S. Itaralde  Purged and Enema Biopsy ​ Use of purgative solution. Demonstrates parasitic stages using specimens ​ Used when negative in O&P examination but from skin, superficial lymph nodes, etc. with strong clinical suspicion of E. histolytica Corneal Scrapings infection. ​ Used for diagnosing Acanthamoeba ​ Performed by irrigating the cecal area. keratitis. Urine and Genital Specimen ​ Placed in a sterile, airtight container or ​ Detects S. haematobium eggs, Wuchereria, inoculated into non-nutrient agar plates Onchocerca, Loa loa, Burgia microfilariae, (Culbertson’s medium). and T. vaginalis trophozoites (rare). ​ Examined using calcofluor white stain or ​ Vaginal discharge and prostatic secretions processed as a histologic specimen. are examined via direct wet mount for the Cerebrospinal Fluid presence of T. vaginalis. ​ Obtained by lumbar puncture. ​ Do not delay viewing of the specimen ​ Sediment is examined via wet mount because it will dry up. technique for motile trophozoites. Sputum ​ Permanent stained smears prepared for ​ Collected in the basal state. Naegleria, Acanthamoeba, Toxoplasma, ​ Must be from lower respiratory passages, and Trypanosoma. not saliva. Mouth and Nasal Discharge ​ Used for detecting pleuropulmonary ​ Associated with poor oral hygiene. amoebiasis, E. granulosus free scolices, P. ​ Nasal discharge: Detects N. fowleri. westermani eggs, and parasites migrating ​ Mucosa and gingival infections: Detects E. through the heart-lung route. gingivalis/T. tenax. Blood Specimen ​ Collected in a sterile, airtight container or ​ Second most common specimen by swab and examined via direct wet mount. examined. ​ Recovers malarial parasites, filarial worms, trypanosomes, leishmanial, and toxoplasma. ​ Examined fresh, stained, or through concentration techniques (e.g., Knott’s & Millipore Filter Techniques). ​ Serum may be used for serologic tests. Aspirates Proctoscopic aspirates and scrapings Confirm amebic ulcers in the lower sigmoid colon and rectum. Duodenal aspirates Collected via duodenal intubation or Entero-test method for G. lamblia, S. stercoralis, F. buski, and Cryptosporidium. Liver and lung aspirates ​ Use direct wet mount, permanent stained slides, or culture techniques. ​ Cysts may be examined directly or mixed with 10% KOH for the presence of hydatid sand. LESSON #1 (BSML-2211) Clinical Parasitology - LAB Lorin Sophia S. Itaralde  LESSON #2: STOOL EXAMINATION BSML-2211 2nd SEMESTER | ACADEMIC YEAR: 2024-2025 | JOHN DARYLL NACUA ​ Watery or diarrheic stool: Ideal for detecting STOOL EXAMINATION trophozoites. ​ Must be properly collected and transported ​ Immediate examination is crucial to avoid disintegration of protozoan trophozoites. without delay. ​ Do not leave stool exposed to air. ○​ Important in obtaining high-quality ○​ Stool will be contaminated and will dry stool because certain diagnostic stages up. of parasites will deteriorate if ​ Do not freeze or incubate the sample. processing is delayed. Structures Mistakenly Viewed ​ Should be processed immediately upon receipt in the laboratory. Stool Collection & Handling ELEMENT/ MISTAKENLY DISTINGUISHING STRUCTURE SEEN AS ​ Collected in a clean, wide-mouth container with tight-fitting lids and sealed in plastic Epithelial Amoebic Amoeba has bags for transport. cells and trophozoites bigger nuclei ​ Must be collected prior to any anti-diarrheal macrophage medications, radiological studies using barium, bismuth, or mineral oil. Amoebic cyst Pus Cells Amoebic Cyst has distinct ○​ With medications, parasites may not be cell wall present. ○​ For oil-contaminated stool, mix with Larvae has saline solution to assist examination. Hairs and Larvae internal Fibers ​ Water and oil do not mix, resulting structure in oil droplets. ​ Oil droplets make it very difficult to Cyst has thin Plant Cells Cyst view the specimen under the cell walls microscope. Yeasts and ​ If under treatment, collect stool 5-7 days after Yeast and Amoebic Cyst Molds are therapy completion. Molds smaller ​ Avoid contamination with any liquids, such as urine or water. Eggs of ​ Worms, eggs, and protozoan parasites are arthropods Parasites best detected in stool after enemas. and plant nematodes ​ Stool samples collected after using oil laxatives, barium, or bismuth salts are not suitable for examination. ​ Urine contamination in stool samples is not acceptable as it kills protozoan trophozoites rapidly. ​ Water contamination promotes the growth of non-pathogens, making examination difficult. ​ A series of specimens should be collected to rule out a negative result, as trophozoites and cysts may appear intermittently. ​ Formed stool: Ideal for detecting protozoan cysts. LESSON #2 (BSML-2211) Clinical Parasitology - LAB Lorin Sophia S. Itaralde  Schaudinn’s Solution Amount of Specimen ​ Suitable for fresh fecal material, but less effective than PVA. Formed Stool ​ Contains mercuric chloride, which is toxic 5-7 grams (marble/thumb size) to humans, and is not recommended. Watery/Diarrhea Polyvinyl Alcohol 10mL ​ Excellent fixative for intestinal protozoa in trophozoite stage, helminth eggs, and Timing of Collection larvae. ​ 3:1 ratio of PVA to stool. General recovery and identification ​ Very good if you plan to stain the sample. ​ Submit 3 specimens for routine examination Merthiolate-Iodine Formaldehyde (MIF) on alternate days. ​ Acts as both a preservative and stain for ​ No more than 10 days' interval between fecal specimens. specimens. ​ Useful in field surveys as it preserves all High suspicion of intestinal amoebiasis stages of parasitic diagnostic stages. Submit a total of 6 specimens within no more Sodium-Acetate Formaldehyde than 14 days. ​ Alternative to Schaudinn’s solution. Patients under therapy for protozoan ​ Contains 10% formalin (fixative) and sodium infections acetate (buffer). Must be checked 3-4 weeks post-therapy. Transportation of Stool Patients under helminths infections ​ Check 1-2 weeks post-therapy. 10% Formalin (wet mount) ​ May extend to 5-6 weeks for Taenia infections. MIF (wet mount) Stool Preservation ​ Preservation is done when processing of PVA (permanent staining) samples cannot be done immediately. ​ Fixatives are substances that preserve the morphology of protozoa and prevent further development of certain helminth eggs and larvae. ​ A 3:1 ratio of fixative to stool must be observed, regardless of the type of fixative used. Refrigeration ​ Temperature: 4-8°C. ​ Protozoan trophozoites can be preserved for several days. ​ Cysts can be preserved for several weeks. Formalin ​ Acts as a fixative. ​ Known as the all-purpose fixative. ​ For preserving helminths and larvae, use a 10% concentration. ​ For protozoan cysts, use a 5% concentration. LESSON #2 (BSML-2211) Clinical Parasitology - LAB Lorin Sophia S. Itaralde