Ascariasis Etiology
- Ingestion of eggs in contaminated food
- Ascaris lumbricoides nematode (roundworm)
Ascariasis S/S
Transient cough, urticaria, pulmonary infiltrates, nonspecific abd symptoms
-fever, nonproductive cough, chest pain
Ascariasis Lab
- Adult worms may emerge from mouth, nose, or anus
- ID eggs in feces
- Eosiniphilia on CBC
- Abd ultrasound will ID worms
Ascariasis Management
-Worms may migrate to common bile duct, pancreatic duct, appendix
-Heavy infestation may cause intestinal obstruction, vovulus, intussusception, death
Tx: albendazole, mebendazole, or pyrantel pamoate
Ascariasis Prev/Prog
- Infections are high in areas of poor hygiene
- Reinfection is common in endemic areas
Enterobiasis Etiology
Enterobius vermicularis (pinworm)
- ingest eggs from infected individual, contaminated food, infected clothing/bedding
- Deposit eggs on perianal skin
Enterobiasis S/S
Nocturnal perianal pruritius
- asymptomatic
- insomnia, restlessness, enuresis
- mild GI symptoms
Enterobiasis Lab
ID eggs or adult worms on perianal skin or in stool
-apply clear tape to perianal skin in early morning and examine under microscope
Enterobiasis Management
Tx: single dose of albendazole, mebendazole, or pyrantel pamoate
- repeat in 2 wks due to frequent reinfection
- Treat all close contacts
Enterobiasis Prev/Prog
- hand washing
- washing clothes/bedding will kill
- easily cured but reinfection is common
Trichinosis Etiology
Trichinella spiralis and other Trichinella species
- ingestion of inadequately cooked pork or game
- larvae are freed from cyst from gastric acid and passes to small intestine
- larvae invade intestinal epithelial cells and release larvae
- invade skeletal muscle
Trichinosis S/S
Transient intestinal symptoms followed by fever, myalgias, and periorbital edema
- asymptomatic
- HA, cough, dyspnea, hoarseness, rash, subconjunctival and retinal hemorrhages
- symptoms peak 2-3wks and lasts 2 months
Trichinosis Lab
Eosinophilia
-elevated serum muscle enzymes
Trichinosis Management
- No specific therapy
- Mebendazole or albendazole will limit tissue invasion
- supportive therapy: analgesics, antipyretics, bed rest, steroids in severe illness
Trichinosis Prev/Prog
-Cook meat
Tapeworm Etiology
Infected by eating raw/undercooked meat/ freshwater fish 4 Sources -Beef: Taenia saginata, largest -Pork: Taenia solium -Fish: Diphyllobothrium latum -Dwarf: Hymenolepis nana
Tapeworm S/S
Generally asymptomatic
-can have abd pain or GI symptoms (N/D)
Tapeworm Lab
CBC: eosinophilia
-infection is discovered by finding proglottids or eggs in stool
Tapeworm Management
Tx: praziquantel
Tapeworm Prev/Prog
-responds well to tx
Cysticercosis Etiology
Taenia solium
- fecal contamination of food
- humans are intermediate host
Cysticercosis S/S
Seizures, HA, focal CNS deficits
- altered cognition, psychiatric disease
- vomiting, papiledema, vision loss
- intracerebral, subarachnoid, and spinal cord lesions and intraventricular cysts
- lesions may persist for years before symptoms develop
Cysticercosis Lab
Brain imaging shows cysts
- positive serologic test
- CSF shows lymphocytic or eosinophilic pleiocytosis, decreased glucose, elevated protein
- ELISA
- CT or MRI show cysts and perenchymal calcifications
Cysticercosis Management
Tx: benefits must be weighed against inflammatory response risk
- Albendazole is tx of choice and is coadministered with corticosteroids
- Surgically remove cysts
Cysticercosis Prev/Prog
Endemic in Mexico, Central and S America, Philippines, SE Asia
- High fatality rate if untreated
- Sanitation, fully cook pork
Cutaneous larva Migrans Etiology
Caused by dog and cat hookworms (Ancylostoma braziliese and canium)
Cutaneous larva Migrans S/S
Intense pruitic erythematous papules, usually on feet or hands
- serpiginous tracks mark the path of parasite
- lesions become vesiculated, encrusted or secondarily infected
Cutaneous larva Migrans Lab
Dx based on characteristics of lesion
-no lab or bx is done
Cutaneous larva Migrans Management
Mild cases don’t require tx
- Thiabendazole (topical) TID x 5 days or more
- Systemic tx: albendazole or ivermectin
Cutaneous larva Migrans Prev/Prog
- infection common in SE US
- Most common in kids
Hookworm Etiology
Ancylostoma duodenale or Necator americanus
- larvae penetrate skin and migrate to bloodstream to pulmonary capillaries
- carried by ciliary action up bronchi to mouth and are swallowed
- attach to mucosa of upper small bowel and mature
- suck blood at attachment site
Hookworm S/S
Transient pruritic rash, dry cough, wheezing, low-grade fever, anorexia, diarrhea, abd discomfort
- asymptomatic
- epigastric pain
- pallor, weakness, dyspnea, heart failure due to iron deficiency anemia
Hookworm Lab
Eggs and occult blood in stool
- Dx is based on eggs in feces
- eosinophilia is common
Hookworm Management
Tx: albendazole or mebendazole
-iron replacement to manage anemia
Hookworm Prev/Prog
- Very common in tropical and subtropical regions
- mass tx of children with single dose at regular intervals limits worm burden in endemic areas
Schistosomiasis Etiology
Caused by trematode blood flukes - 5 Schistosoma species
-Fresh water snails in endemic areas
Schistosomiasis S/S
Acute onset of fever, HA, cough, myalgia, urticaria, diarrhea (bloody)
-’swimmer’s itch’
Intestinal: abd pain, hepatomegaly, anorexia, weight loss
Urinary: hematuria, dysuria
Chronic: may be light and asymptomatic
Schistosomiasis Lab
Dx: eggs in feces or urine, bx of rectal or bladder mucosa, positive serology
- stool may be neg for eggs early on
- CBC: eosinophilia
Schistosomiasis Management
Tx: praziquantel (1-2 doses, may repeat in 2 wks)
- combine with corticosteroid in severe disease
- alternative tx: oxamniquine, metrifonate, artemether
Schistosomiasis Prev/Prog
Resolves in 2-8 wks
- high cure rates w/ tx
- avoid fresh water in endemic areas
Scabies Etiology
Sarcoptes scabiei
-acquired through bedding or close contact with infested person
Scabies S/S
Severe itching, pruritic burrows, vesicles, and pustules (especially on finger webs and wrist creases, elbows, around axillae, and breasts)
- nodular lesions on scrotum, penis, or posterior axillary line
- pruritic papules on butt
Scabies Lab
Mites, ova, and brown dots of feces visible micoscopically
-scrape each lesion until it is flat
Scabies Management
Tx: permethrin cream
- dermatitis can last months after eradication of mites
- Tx dermatitis with corticosteroid cream
- bedding and clothing should be cleaned or set aside in plastic bags for 2 wks
- High heat is required to kill mites and ova
Scabies Prev/Prog
- crusted/hyperkeratotic lesions should be evaluated for immunosuppression
- must tx all persons in household
