Report On Ascaris Lumbricoides, Its Factors, Diagnosis And Identification
Clinical Manifestations
A lumbricoides infections involving only a few worms are usually asymptomatic, but as the worm load increases, symptoms of abdominal discomfort, nausea, vomiting, weight loss, fever, and diarrhea develop. Allergic manifestations in hypersensitized persons lead to pneumonitis, cough, low-grade fever, and eosinophilia. Large numbers of worms may form a bolus and cause intestinal obstruction. Stimulation causes adult worms to become erratic and invade the appendix and bililary and pancreatic ducts. Worms may enter and block small orifices. Migrating adults have been vomited and passed from the nose and mouth, anus, umbilicus, and lacrimal glands. They can perforate the intestines and enter the peritoneal cavity, the respiratory tract, urethra, and vagina, and even the placenta and fetus. Excessive worm loads, especially among the malnourished, can lead to nutritional impairment because the worms interfere with the absorption of proteins, fats, and carbohydrates.
Diagnosis
Symptomatic ascariasis is rarely diagnosed on clinical grounds alone because the pneumonitis, eosinophilia, and intestinal symptoms are similar to those caused by other infectious agents. Infections before the appearance of eggs in the feces, infections with only male worms, and extraintestinal infections are difficult to diagnose. Radiologic computed tomography (CT) and sonographic examination may reveal adult worms in the intestine and bile ducts, but definitive diagnosis requires finding characteristic eggs in feces. Eggs are usually so numerous in any infection involving female worms that simple microscopic examination of a fecal smear is all that is necessary. Concentration techniques involving flotation or sedimentation of eggs also may be used. Techniques are available to estimate the intensity of an infection on the basis of the number of eggs in a measured stool sample.
Specimen Type: Faeces in SAF preservative, whole worm
Specimen Handling: Place specimen container in a biohazard bag and seal.
Reminder: Store the yellow capped container at room temperature at all times. The white capped container must be refrigerated before submission or frozen if there is a delay of more than 72 hours.
The submission of the white top container will allow for method development of newer and more sensitive methods such as enzyme immunoassay (EIA) and polymerase chain reaction (PCR) to obtain improved species identification.
Identification
Ascaris specimens are examined by microscopy following centrifugation procedure using the Formalin/Ethyl-Acetate Concentration Method. The concentration method allows for detection of small numbers of organisms. Both fertilized and unfertilized eggs can easily be recovered by the sedimentation concentration method. (Unfertilized eggs do not float with use of the zinc sulfate flotation concentration method. )
A permanent stained smear is also examined for Ascaris eggs. Eggs may be very difficult to identify on a permanent stained smear because of stain retention and asymmetric shape.
Identification of Ascaris lumbricoides ova using trichrome stains: The albuminoid cortex of both fertilized and unfertilized Ascaris ova will be stained very dark brown, blue- black, or sometimes green. The coarse mammillations of the shell will also be visible and, due to their large size, focusing on several places would be necessary at a higher magnification to reveal the embryo inside the fertilized ovum. There will be no distortion of the oval shape and no shrinkage.
Whole worms are examined by microscopy for identification. If too much iodine is added to the wet preparations, the eggs may look like very dark debris (7). v X-ray, Magnetic Resonance Imaging (MRI) scan, Computerized Axial Tomography scan (CAT) - these tests are used to look for some parasitic diseases that may cause lesions in the organs.
