-
Parasitic worms
- called helminthsadult worms are large enough to see with the naked eye
- ova and larve need microscope to view
- 2 major groups: Nematodes (roundworm) and Cestodes (tapeworm)
-
Nematodes (roundworm)
- found in every habitat on earth --> sea, fresh water, soil, frutis, vegetables from polar regions to tropics
- they parasitize every type of animal and plan causing economic damage and serious disease
- structure: bodies are not segmented, but pointed at both ends; have complete digestive, excretory and nervous system; have seperate sex organs, and females may lay 200K eggs per day
- worms includes: Necatur americanus, Ascaris lumbricoides, and Trichinella spiralis
-
Necatur americanus
- American hookworm
- Transmission: larvae penetrates exposed skin then enter the circulatory system
- Prevention: wear shoes, maintain proper sanitation for disposal of human waste
- Disease: severe anemia, abdominal pain, diarrhea
- Dx: Hookworms in O&P
- Tx: Vermox
-
-
Dog and Cat hookworm
- lifecycle is similar to human hookworms, but it cannot penetrate human skin.
- it remains alive in the epidermis causing skin irritation called Creeping eruption or Ground itch
- Tx: Thiabendazole topical cream
"Swimmer's Itch" is caused by goose feeces
-
Ascaris lumricoides
- largest of roundworms measuring 20-30 cm
- life cycle is similar to hookworms
- Transmission: enters the body via ingestion of eggs and travels to the lungs via circulatory system, patients cough up the larvae and swallow it and it gets to the digestive tract
- Disease: severe pneumonitis, coughing, asthmatic breathing, diarrhea, vomiting, and abdominal pain
- Dx: O&P exam of stool and look for Ascaris eggs
- Tx: Vermox and look for passing of dead Ascaris in stool
-
Trichinella spiralis
- Transmission: eating infested bear or pork that has been undercooked
- Life cycle: man is the alternate host
- Disease:
larvae is embedded in any muscle affecting heart, abdominal, tongue, biceps; the severity of disease depends on the number of viable larvae is eaten. Infection includes mild GI discomfort, muscle pain, chills, weakness, increase eosinophils over 40%. In severe infection-respiratory distress, heart involvement and death - Dx: muscle biopsy where the pain is, skin test, and increase eosinophils in WBCs
- Tx: Thiabendazole
- *muscle destruction is irreversible although new muscle cells will grow
- *recovery begins when larval migration ends about 3-8 weeks
-
Enterobius vermicularis
- aka Pinworms
- smallest parasitic roundworm and is the most common of all helminth infections
- Transmission: ova on perianal skin of infected persons; direct or indirect transfer to others through clothing, bedding, toys, or food
- Disease: anal scratching, itching, restlessness, insomnia
- Dx: scotch tape or pinworm paddle pressed to the perianal area, exam for ova and parasites
- Tx: Vermox and Piperazine
- Prevention: Good hygeine, disinfect linens, toys, clothing
|
|