PARASITOLOGY - 1ST HALF

• Class Phasmedia possess caudal chemoreceptors called phasmids
• Class aphasmidia lacks caudal chemoreceptors
• Anterior or cephalic sensory organ called amphids
• Two types of esophagus are filariform and rhabditiform
• Filariform is uniform throughout the body
• Rhabditiform expands psoteriorly into a bulb with a bulb mechanism
• Polymyarian refers to a more than five rows of cells
• Meromyarian refers to between two to five rows
• Holomyarian refers to a less than two rows
• Rhabditiform is a stage that hatches from the egg
• Filariform larvae is characterized the infective form of the parasite
• There are six mode of transmission: ingestion, larva, skin penetration, inhalation, trans mammary, and vector
• Ascaris lumbricoides is the most common intestinal nematodes
• Ascaris lumbricoides is a giant round worm
• The soil is the major role in the developmental and transmission of ascaris lumbricoides
• Ascaris lumbricoides is a disease of the poverty, malnutrition and impairment of cognitive performance, reduce work capacity and productivity of adults
• The ascaris lumbricoides is whitish or pinkish in color
• The male of ascaris lumbricoides is 10-31 cm long while the female is 22 - 35 cm long
• Ascaris lumbricoides has a so-called “polymyarian type” of somatic muscle arrangement in which cells are numerous and project well into the body cavity.
• Ascaris has been shown to produce pepsin inhibitor 3 (PI-3) that protects worms from digestion and phosphorylcholine that suppresses lymphocyte proliferation.
• The infective stage of ascaris is the fully embryonated egg
• When the eggs of ascaris are ingested, they hatched in the lumen of the small intestine, releasing the larvae
• A majority of Ascaris infections are asymptomatic
• During lung migration, the larvae of ascaris may cause host sensitization resulting in allergic manifestations such as lung infiltration, asthmatic attacks, and edema of the lips.
• The most frequent complaint of patients with ascaris lumbricoides is vague abdominal pain
• Direct fecal smear, Kato Katz, and Concentration technique are stool examination techniques used to diagnose ascariasis by confirming the presence of eggs in the feces.
• Kato-Katz technique also provides quantitative diagnosis in terms of the intensity of helminth infection in eggs per gram (epg) of stool that is useful in monitoring the efficacy of treatment in clinical trials, as well as public health programs.
• Individual infections are cured by a single dose of any of the broad-spectrum anthelminthics such as albendazole, mebendazole, and pyrantel pamoate.
• Children ages 5 to 15 years have the highest intensities of infection with Ascaris compared with the other age groups.
• Ascariasis lumbricoides is also known to be able to survive colder temperatures compared with Trichuris and hookworm.
• To prevent and control the ascaris, it is best to use the kato katz methods
• Trichuris trichiuria also known as the whipworm
• Trichuris trichuria is a soil-transmitted helminth, and is classified as holomyarian based on the arrangement of somatic muscles
• The egg of trichuris trichuria is a lemon or football-shaped with plug-like translucent polar prominences. The egg has a yellowish outer and a transparent inner shell.
• Trichuris worms inhabit the cecum and the colon.
• The worms secrete a pore-forming protein, called the TT47 that allows them to imbed their entire whip-like portion into the intestinal wall.
• The lumen of the appendix may be filled with worms, and consequent irritation and inflammation may lead to appendicitis or granuloma formation.
• The drug of choice in the treatment of trichuriasis is mebendazole given 100 mg twice a day for 3 days. Albendazole may be used as an alternative drug.
• Deworming of children with trichuris trichuria has been shown to contribute to improved motor and language development, as well as to reduced malnutrition.
• In tropical and subtropical regions, Trichuris is most prevalent in East Asia and Pacific Island regions, and least prevalent in the Middle East and North African regions.