Presentation is loading. Please wait.

Presentation is loading. Please wait.

Ascaris lumbricoides Suan Lui Teoh Danh Voong. Introduction a common cream colored roundworm that is parasitic in the intestines of humans a common cream.

Similar presentations


Presentation on theme: "Ascaris lumbricoides Suan Lui Teoh Danh Voong. Introduction a common cream colored roundworm that is parasitic in the intestines of humans a common cream."— Presentation transcript:

1 Ascaris lumbricoides Suan Lui Teoh Danh Voong

2 Introduction a common cream colored roundworm that is parasitic in the intestines of humans a common cream colored roundworm that is parasitic in the intestines of humans Most common helminthic human infection Most common helminthic human infection Largest nematode to infect the human intestine Largest nematode to infect the human intestine An estimated 1 billion people are infected (1 out of 4 people in the world) An estimated 1 billion people are infected (1 out of 4 people in the world)

3 Geography Worldwide Worldwide High prevalence in underdeveloped countries that have poor sanitation (parts of Asia, South America and Africa) High prevalence in underdeveloped countries that have poor sanitation (parts of Asia, South America and Africa) Occurs during rainy months, tropical and subtropical countries Occurs during rainy months, tropical and subtropical countries Even occurs in rural areas in the United States Even occurs in rural areas in the United States

4 Host Definitive host : Humans or pigs Definitive host : Humans or pigs Intermediate Host : -none- Intermediate Host : -none-

5 Modes of transmission Occurs mainly via ingestion of water or food (raw vegetables or fruit in particular) contaminated with A. lumbricoides eggs. Occurs mainly via ingestion of water or food (raw vegetables or fruit in particular) contaminated with A. lumbricoides eggs. Occasionally inhalation of contaminated dust Occasionally inhalation of contaminated dust Children playing in contaminated soil may acquire the parasite from their hands Children playing in contaminated soil may acquire the parasite from their hands Enhanced by the fact that individuals can be asymptomatically infected and continues to shed eggs for years Enhanced by the fact that individuals can be asymptomatically infected and continues to shed eggs for years Prior infection does not confer protective immunity Prior infection does not confer protective immunity

6 Morphology Fertile egg mammillated mammillated thick external layer thick external layer unembryonated unembryonated measures mm by mm measures mm by mm

7 Morphology Cont. Infertile egg elongated and larger than fertile egg elongated and larger than fertile egg thin shelled thin shelled shell ranges from irregular mammillations to a relatively smooth layer completely lacking mammillations shell ranges from irregular mammillations to a relatively smooth layer completely lacking mammillations measures between mm by mm measures between mm by mm

8 Morphology Cont. Infertile Infertile Fertile Fertile

9 Egg Can survive for prolonged periods as long as warm, shade, moist conditions are available and can live up to 10 years Eggs are resistant to unusual methods of chemical water purification Eggs are removed by filtration and killed by boiling. Developing larvae are destroyed by sunlight and desiccation

10 Morphology Cont. Adult worm: tapered ends; length 15 to 35 cm tapered ends; length 15 to 35 cm Female are larger in size and have a genital girdle Female are larger in size and have a genital girdle

11 The 3 prominent lips

12 Life Cycle

13 Life Cycle Cont. 1. Females lay eggs in small intestine and eggs are passed out through feces. 2. After 14 days, L1 larvae develops in eggs 3. L2 larvae develops after one week 4. Ingestion of raw foods, fruits or vege contaminated with eggs will cause infection 5. Eggs hatch in small intestine, releases L2 rhabditiform larvae 6. L2 penetrate intestinal wall, enter portal blood stream, migrate to liver, heart and lungs in 1-7 days 7. Moults twice to become L4 larvae

14 Cont. 8. Borrow out of blood vessels and enter bronchiols 9. Migrate through the lungs into the trachea 10. Enter throat and swallowed to end up in the small intestine 11. Mature and mate, where they complete their life cycle

15

16 Food Habits Feeds on semi-digested contents in the gut Feeds on semi-digested contents in the gut Evidence show that they can bite the intestinal mucus membrane and feed on blood and tissue fluids Evidence show that they can bite the intestinal mucus membrane and feed on blood and tissue fluids

17 Symptoms Symptoms associated with larvae migration Migration of larvae in lungs may cause hemorrhagic/ eosinophilic pneumonia, cough (Loeffler's Syndrome) Migration of larvae in lungs may cause hemorrhagic/ eosinophilic pneumonia, cough (Loeffler's Syndrome) Breathing difficulties and fever Breathing difficulties and fever Complications caused by parasite proteins that are highly allergenic - asthmatic attacks, pulmonary infiltration and urticaria (hives) Complications caused by parasite proteins that are highly allergenic - asthmatic attacks, pulmonary infiltration and urticaria (hives)

18 Symptoms Cont. Symptoms associated with adult parasite in the intestine Usually asymptomatic Usually asymptomatic Abdominal discomfort, nausea in mild cases Abdominal discomfort, nausea in mild cases Malnutrition in host especially children in severe cases Malnutrition in host especially children in severe cases Sometimes fatality may occur when mass of worm blocks the intestine Sometimes fatality may occur when mass of worm blocks the intestine

19 HOST IMMUNE RESPONSE Innate Immune Response Macrophage, neutrophils and most importantly eosinophils Macrophage, neutrophils and most importantly eosinophils The worms would be coated with IgG or IgE which would increase the release of eosinophil granules on the worms surface The worms would be coated with IgG or IgE which would increase the release of eosinophil granules on the worms surface Adaptive Immune Response General consensus is a Th2 immune response with high IL-4 production, high levels of IgE, eosinophilia and mastocytosis General consensus is a Th2 immune response with high IL-4 production, high levels of IgE, eosinophilia and mastocytosis

20 Diagnosis Stool microscopy :eggs may be seen on direct examination of feces. Stool microscopy :eggs may be seen on direct examination of feces. Eosinophilia: eosinophilia can be found, particularly during larval migration through the lungs Eosinophilia: eosinophilia can be found, particularly during larval migration through the lungs Imaging: In heavily infested individuals, particularly children, large collections of worms may be detectable on plain film of the abdomen. Imaging: In heavily infested individuals, particularly children, large collections of worms may be detectable on plain film of the abdomen. Ultrasound: ultrasound exams can help to diagnose hepatobiliary or pancreatic ascariasis. Single worms, bundles of worms, or pseudotumor-like appearance, individual body segments of worms may be seen. Ultrasound: ultrasound exams can help to diagnose hepatobiliary or pancreatic ascariasis. Single worms, bundles of worms, or pseudotumor-like appearance, individual body segments of worms may be seen. Endoscopic Retrograde Cholangiopancreatography (ERCP) : Endoscopic Retrograde Cholangiopancreatography (ERCP) : A duodenoscope with a snare to extract the worm out of the patient

21 Treatment Mebendazole Mebendazole Albendazole Albendazole Pyrantel pamoate Pyrantel pamoate Ivermectin Ivermectin Piperazine citrate Piperazine citrate Levamisole Levamisole

22 Prevention Prevention of reinfection poses a substantial problem since this parasite is abundant in soil – therefore good sanitation is needed to prevent fecal contamination of soil Prevention of reinfection poses a substantial problem since this parasite is abundant in soil – therefore good sanitation is needed to prevent fecal contamination of soil Limit using human feces as fertilizer Limit using human feces as fertilizer Treatment can be done on contaminated soil although it is not highly advised Treatment can be done on contaminated soil although it is not highly advised Mass treatments of children with single doses of mebendazole or albendazole – helps reduce transmission in community but can cause reinfection Mass treatments of children with single doses of mebendazole or albendazole – helps reduce transmission in community but can cause reinfection

23 Some cool pictures

24

25

26 How many people in the world are estimated to be infected with A. lumbricoides ?

27 Who are the definitive host/s of this parasite?

28 Name 2 modes of transmission?

29 What morphological difference can be seen in fertile and infertile eggs?

30 Name the symptom caused by larvae migration in the lungs.

31 What is the drug of choice for this parasite?

32 What are some of the methods of prevention?

33


Download ppt "Ascaris lumbricoides Suan Lui Teoh Danh Voong. Introduction a common cream colored roundworm that is parasitic in the intestines of humans a common cream."

Similar presentations


Ads by Google