DIAGNOSTIC
STAGE
INFECTIVE STAGE
SITE OF
INFECTION
Ascaris
lumbricoides
Giant intestinal
roundworms
Eelworm
Roundworm of Man
Egg – fertilized or
unfertilized
Ingestion of
infective/
embryonated eggs
from contaminated
soil
Small intestines
Larvae thru lungs
Enterobius
vermicularis
Pinworm
Seatworm
Eggs in perianal
folds
Embryonated eggs
containing 3rd stage
larva
Lumen of cecum
Colon
Trichuris
trichiura
Whipworm
Unembryonated
eggs passed in
feces
- Becomes
infective after
3 -5 weeks
embryonated eggs
Cecum
Colon
HOOKWORMS
Ancylostoma
duodenale
Old World hookworm
Necator
americanus
New World
hookworm
Eggs in feces
Filariform LArva
Penetrated skin
Small intestines
Larvae through
skin and lungs
Strongyloides
stercoralis
Threadworm
Rhabditiform
larvae
Filariform larvae
Small intestines
Larvae through
skin and lungs
Trichinella
spiralis
Encysted larva
Encysted larva in
striated muscle
Adults in SI for 1 -
4 months;
Larvae encysted
in muscle tissue
CLINICAL MANIFESTATIONS
Ascaris
lumbricoides
Giant intestinal
roundworms
Eelworm
Roundworm of Man
●Allergic reaction
●Respiratory symptoms
○ Asthmatic respiration
○ Cough with bronchial rales
○ Chest pain
●Ascaris Pneumonitis
○ Loeffler’s syndrome
■ Allergic eosinophilic infiltration of lung
●Fever, utricaria, edema
●Intestinal obstruction, intussusception or volvulus
○ From ascaris bolus
○ Bowel infarction
○ Intestinal Perforation
●Lactase intolerance and Vit A malabsorption
●Biliary ascariasis
○ Colicky abdominal pain
○ Or Vague abdominal pain
●Acute biliary obstruction or Pancreatitis
●Appendicitis
●Acute peritonitis or chronic granulomatous
peritonitis
Enterobius
vermicularis
Pinworm
Seatworm
●Enterobiasis or oxyuriasis
●Typically characterized by perianal itching or pruritus
ani
●Mild catarrhal inflammation of the intestinal mucosa
●Irritation and itching in the perianal region
●Secondary bacterial infection due to scratching
●Insomnia due to pruritus in children
●Systemic manifestations:
○ Poor appetite
○ Weight loss
○ Irritability
○ Teeth grinding
○ Abdominal pain
●Complications:
○ Appendicitis
○ Vaginitis
○ Endometritis
○ Salpingitis
○ Peritonitis
Trichuris
trichiura
Whipworm
●Usually asymptomatic except with heavy infection ( with
a high worm burden (greater than 200 worms, >5,000
EPG)
●Common symptoms found in infected person:
○ Abdominal tenderness and pain
○ Weight loss
○ Weakness
○ Mucoid or bloody stool
●Iron-deficiency anemia
○ hypochromic, microcytic type
○ Results from chronic blood loss at the attachment
site coupled with the long life span of the worms.
●Small amounts of blood (0.8 to 8.6 ml) are lost each
day at the ulceration in the intestinal mucosa.
●The worm may be found even up to the rectum in heavy
infection
○ May cause rectal prolapse
○ Mucosa of the rectum protrudes through the anal
opening associated with the loss of muscle tone of
the anus.
●Children with severe trichuriasis
○ Growth retardation
○ Impaired mental development and cognitive
function
HOOKWORMS
Ancylostoma
duodenale
Old World hookworm
Necator
americanus
New World
hookworm
●Acute:
○ Common in A. duodenale
○ Fatigue, nausea, vomiting, burning and cramping
abdominal pain, diarrhea
●Chronic
○ Iron deficiency Anemia
■ Pallor, facial and pedal edema
■ Hookworm Disease
●Hemorrhage
●Pulmonary Lesion
○ Wakana disease in Japan
■ Itching pharynx
■ Hoarseness
●Hypoalbuminemia
○ Due to combined loss of blood, lymph and protein
CUTANEOUS LARVA MIGRANS
Aka Creeping Eruptions of Zoonotic Hookworms
●Ground itch/ Coolie/ Dew itch:
○ Allergic Dermatitis
○ Fungal infection
○ Penetration of the filariform larvae through the skin
produces maculopapular lesions and localized
erythema.
●Pulmonary Phase
○ Asthma and atypical pneumonia
○ Pneumonitis and Bronchitis
■ occurs if larvae migrating to lungs are
abundant
■ Produce – minute hemorrhage with
eosinophilic and leukocytic infiltration (rare)
●Intestinal Phase
○ Enteritis
○ Iron-deficiency anemia
○ Maturation of Worm →
■ Abdominal pain
■ Steatorrhea
■ Diarrhea with blood, mucus and eosinophilia
VISCERAL LARVA MIGRANS
Zoonotic disease
Humans – accidental host
ASCARID LIFE CYCLE
Strongyloides
stercoralis
Threadworm
●Cutaneous manifestations:
○ There may be dermatitis, with erythema and itching at the
site of penetration of the filariform larva, particularly
when large numbers of larvae enter the skin.
○Creeping eruption or larva migrans
●Larva Currens:
○ Racing larva (rapid progress of 10 cm /hr)
●Pulmonary manifestations:
○ Small hemorrhages
●Intestinal manifestations:
○ “honeycomb” mucosa
○ peptic ulcer like
○ RUQ pain
○ malabsorption
●Cochin China Diarrhea
●Hyperinfection
○ autoinfection
○ long duration
○ parasitic adult females
Trichinella
spiralis
INTESTINAL PHASE
●Gastrointestinal symptoms
○ Diarrhea
○ Abdominal Pain
○ Vomiting
MIGRATION PHASE
●High fever
●Periorbital and facial edema
●Conjunctivitis
●Blurred vision
●Myalgias
●Splinter hemorrhages
●Rashes, and peripheral eosinophilia lasting 1 month in
heavy infection.
●Occasional life-threatening manifestations include:
○ myocarditis, central system nervous involvement,
pneumonitis.
LARVAL ENCYSTMENT
●Myalgia and weakness, followed by subsidence of
symptoms.
●Other symptoms vary depending on the location and
number of larvae present.
