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Pinworm Life cycle
- Direct life cycle
- -gavid female migrate to perianal to deposit
- -become infective in 4-5 hours, (retroinfection)
- -eggs are distributed through linens, air, scratching
- -infected eggs eaten by human
- -hatch in small intestine
- -larvae migrate to colon (restart cycle)
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Pinworm name
Enterobius vermicularis
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Pinworm Info
- Human only
- Eggs are short lived
- Killed by drying
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Pinworm symptoms
- 1/3 of infections are asymptomatic
- -Perianal itching
- -secondary bacterial infections
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Complications of pinworms
- inflammed appendix
- invasion of female genital tract
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Diagnosis of pinworms
- few eggs in feces
- scotch tape test right after waking up (3 days in a row)
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Treatment of pinworms
- anthelminthics for entire family
- doesnt kill all larvae
- best to treat two weeks after first treatment
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Ascariasis
Ascariasis lumbricoides
very rare in US, most in africa and asia - Pig species is A. suum
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Ascariasis life cycle
- DIRECT
- -eggs passed to soil
- -2-4 weeks to become infective
- -human ingest
- -larva hatches in small intestine
- -penetrates mucosa and bloodstream (8-18 hr)
- -migrates to lung then back down to small intestine. become adults and reproduce
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Ascariasis requirements
- poor sanitation and fecal contamination
- extremely resistant to chemicals, not UV though
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Ascariasis symptoms
- depend on intensity
- about 10 worms means abdominal pain, can lead to intestinal blockage
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Ascariasis Diagnosis
- direct fecal exam (easy due to amount of eggs produced)
- passing adults in feces
- fever can cause migration
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Ascariasis treatment
- anthelmenthics
- partial intestinal obstruction- slow dose anthelmentics
- complete obstruction- surgery
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Visceral Larval Migrans characteristics
prolonged fever, persistent eosinophilia, potential eye damage, pneumonitis
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Cause of VLM
Toxacara canis or cati
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VLM life cycle
- -egg in feces
- -J3 ingested by rodent, human, dog
- -in human causes VLM, in rodent its paratenesis, and dog is where it matures.
- -juveniles enter alveoli and mature
- -adult worms mate in small intestine
- -could lead to transplacental transmission to pup (cycle)
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Diagnosis of VLM
- since no adults in humans, no eggs in feces
- Elisa test
- MRI abnormality in brain
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Treatment of VLN
- anthelminthic plus anti inflamatory
- once J3 in CNS tissue, anthelminthics are useless
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prevention of VLM
- Deworm puppies and kitten
- clean up after pets
- cover sandboxes
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Dracunculiasis (Guinea Worm)
- Drucunculus medinensisinfects dogs, cats, horses, cattle, primates
- Focus of global eradication effort
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Dracunculiasis
- Only human nematode transmitted through drinking water
- Female worms emerge from skin
- where there's limited drinking water
- symbol of medicine
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Dracunculiasis life cycle
- INDIRECT
- Humans drink unflitered water containing copepods with J3
- J3 released, mature and reproduce in small intestine
- fertilized female migrates to skin, causes blister, discharges larvae
- J1 released into water, consumed by copepod
- J1->J3 in copepod (Cycle)
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Treatment of Dracunculiasis
- No effective drug treatment known, some anti-inflammatories help
- surgery when worm is in appropriate area
- worm on stick to remove
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Dracunculiasis control
- Prevent human entry into drinking water sources, isolate infected
- Kill copepods with Abate
- Filter water
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lymphatic filariasis
- Wuchereria bancrofti (Only humans)
- Brugia malay
i (Cats and monkeys)
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Life cycle of Lymphatic filariasis
- INDIRECT
- Mosquito ingests microfilariae when biting human
- ingested MF develop into filariform juveniles
- infected mosquitoes transmit filariform juvenile to human
- juveniles migrate via lymphatics to regional lymph nodes
- mature to adult worms in afferent lymphatic vessels and reproduce
- microfilariae migrate to blood stream (cycle)
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Filarioidea - Generalized life cycle
- Female worms ovoviviparous (live bearing, eggs hatch within), produce microfilaria
- Mosquito has to feed twice in order to transmit
- Symptoms due to adults
- Nocturnal periodicity (10pm-2am)
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Biological vectors of Lymphatic filariasis
- W. bancrofti: anopheles, culex, aedes
- b. malayi: Mansonia
Requires 6-20 days to develop in vector, depends on mosquito
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Clinical phases of Lymphatic filariasis
- Pre-patent period: 6-12 months
- Asymptomatic phase: microfilaria in blood by no response from immune system
- Acute phase: chills, fecer, swelling, inflammation
- Obstructive phase: (YEARS) hydrocoele (testes), chyluria, elephantiasis
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Diagnosis of lymphatic filariasis
- Blood sample, requires proper sampling time of blood
- Some infected produce no microfilaria in blood
- ELISA test
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Treatment of lymphatic filariasis
- community based treatment
- DEC against adults and microfilaria
- Ivermectin kill MF only
- surgery
- Control: DEC + albendazole 2 yearly dose reduces MF
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Onchocerciasis
- River blindness
- Onchocerca volvulus (Only humans)LC like filariasis (INDIRECT) but with black fly vector and development short
- Damage due to juveniles
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onchocerciasis Variation in disease presentation
- Africa: arms, thighs, trunks (lowland and forest disease)
- Central and south america: associated with coffee growing, tend to bite head due to limited skin exposure.
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Features of onchocerciasis
- MF remain primarily on skin
- symptoms mainly due to MF
- inflammation due to cell mediated reactions against MF
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onchocerciasis infections
- Prepatent period up to a year
- SKIN ITCHING, abnormal pigmentation, loose, thickening, Hanging groin
- Photophobia, sensation of foreign body in eye, eventual eye lesions
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Diagnosis of Onchocerciasis
Skin snips, Mf will swim out of skin into saline
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Treatment of Onchocerciasis
- Field removal
- anthelminthic
- Ivermectin (acts slowly, inhibits MF)/DEC
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plant root parasite classification
- ectoparasites: adult remains outside root but feeds on root tissue stylet
- endoparasites: migratory-move through plant tissue. sedentry- stays at one site
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Root-knot nematodes
- Meloidogynemost important plant parasites with respect to economic impact
- elicits root border cell defense which paralyze nemas
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life cycle of Meloidogyne
- J2 hatches from egg, is attracted to root zone
- J2 penetrates root, migrates between cells
- Female induces giant cell formation in root
- Eggs deposited in gelatinous matrix
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Symptoms of infection from meloidogyne
stunted growth, yellow leaves, wilting, reduction in root number, root galls
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Entomophathogenic nemas (EPN)
- nemas that quickly kill their insect host
- Steinernmema
- Heterorhabditis
- effective for biological control of insects with a growth stage in soil
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EPN bacterial system
- suppress insect immune system
- produce toxins that kill infected host within hours
- digest insect cadaver
- produce antibiotics that reduce growth of other microflora
- produce pigments/light
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Heterorhabditis
- nemas are hermaphrodites, 1 J3 can start infection
- adhere to nema intestinal surface
- has cuticular tooth in J3
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Steinernema
- Xenorhabdus
- requires 2 J3
- HAS INTESTINAL POUCH FOR BACTERIA
no cuticular tooth - enters through natural body openings
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