Laboratory: Lab Specimen for Parasite Examination Flashcards
There are two ways of diagnosing parasitic infection:
Demonstration of parasites
Detection of the host’s immune responses to the
parasite such as detection of antibodies and antigen (serological testing)
The two most commonly requested specimens for parasite examination:
Fecal specimens for ova and parasite (O&P)
Blood specimen for malarial parasites
Examined primarily to obtain diagnostic evidence of infection with Entamoeba histolytica usually in the cecal area
Purged and Enema Specimens
The only amoeba that is pathogenic
E. histolytica
Purgative solutions that maybe used
Magnesium sulfate (Epsom salts)
Sodium sulfate
Phosphosoda
Purged materials to be examined are
Tissue detritus and mucus in
the liquid portion
Enema specimens should be obtained by
High instillation of tepid physiologic salt solution (NSS)
The specimen of choice for the recovery of Schistosoma
haematobium eggs, microfilariae of Wuchereria, Onchocerca, Loa and Brugia, and on rare occasions, Strongyloides larvae
Urine
The bladder flukes which have prominent and terminal spine during their egg stage
Schistosoma haematobium
Trophozoites that are often recovered from the urine of both male and female patients
Trichomonas vaginalis
Urethral and vaginal discharge specimens and prostatic secretions are examined by
Direct wet mount
T. vaginalis resides in the _ for females
Cervix
Useful in recovering trophozoites of Entamoeba histolytica in cases of pleuropulmonary amebiasis and the free scolices of
Echinococcus granulosus in the event of rupture of pulmonary hydatid cyst
Sputum
The head or part of head of parasite
Scolex or Scolices
Time when sputum is concentrated
Early morning
Sputum can be examined in direct wet mount with _ or _ and can be _
Saline
Iodine
Concentrated using N-Acetyl-L-cysteine (mucolytic agent) and centrifugation
Useful in the recovery of blood parasites such as malarial parasites, filarial worms, Trypanosomes, Leishmania and Toxoplasma
Blood
Gold standard for malarial infection diagnosis
Thick and thin smears
Concentration techniques like _ and _ technique may be performed for diagnosis
Knott’s
Millipore Filter
Used for confirming suspicion of amebic ulcers in lower sigmoid colon and rectum
Protoscopic aspirates and scrapings
For infections with Giardia lamblia, Strongyloides stercolaris, Fasciolopsis buski or Cryptosporidium
Duodenal aspirates
Duodenal aspirates are collected by use of
Tubing
Entero-test method
for Entamoeba histolytica
Liver and lung aspirates
Culture technique that can be used for liver and lung aspirates
Bovine serum medium (Diamond’s or TYI-S-33)
Cyst material can be examined directly or
mixed with a drop of
10% KOH
Used for the diagnosis of Acanthamoeba keratitis
Corneal Scrapings
Corneal Scrapings can be directly inoculated into
Non-nutrient agar plates (Culbertson’s medium) seeded with a suspension of live Escherichia coli
Corneal scrapings can be examined directly using
Calcoflour white stain
Processed as histologic specimen
Certain genera of parasites gravitate to the CNS such as
Naegleria, Acanthamoeba, Toxoplasma and Trypanosoma found in
Cerebrospinal Fluid
A brain-eating amoeba
Naegleria fowleri
Patients with these CSF infections generally exhibit symptoms of
Meningitis
Performed for CSF collection and examination
Lumbar puncture
Entamoeba gingivalis and Trichimonas tenax can be recovered from
Mouth scrapings or Mouth discharge
Collected and examined for the presence of Naegleria fowleri
Nasal discharge
Mouth and Nasal Discharge should be obtained in a
Sterile, air-tight container or
swab
