Transcript Hookworm Infection

HOOKWORM INFECTION
Brandy Kragness & Kerbe Norberg
Geographical Range

Necator americanus
 Sub
Saharan Africa
 Southeast Asia
 China
 Indonesia
 the Americas

Ancylostoma duodenale
 Middle
East
 North Africa
 India
Morphology

Necator americanus
“New World Hookworm”
 Pair of dorsal and ventral cutting plates surrounding the
buccal cavity



Also have subdorsal and subventral teeth near the rear of the
buccal cavity
Males:
7-9 mm long
 Copulatory Bursa with needle-like spicules forming a distal
hook


Females:
9-11 mm long
 Vulva located in middle of body
 Produce 5,000-10,000 eggs per day (Life Span = 5 Years!)
 Eggs: 65-75 μm by 36-40 μm, thin shelled

Necator americanus
dorsal and ventral cutting plates
Morphology

Ancylostoma duodenale
“Old World Hookworm”
 Two ventral cutting plates with two large teeth fused at
their base



A pair of small teeth are located in the capsule as well
Males:
8-11 mm long
 Copulatory Bursa with needle-like spicules that are NOT
fused distally


Females:
10-13 mm long
 Vulva located about 1/3 of the body length from the posterior
end
 Produce 10,000-30,000 eggs per day (Life Span= 1 year)

Ancylostoma duodenale
cutting plates with two large teeth fused
Transmission

Ancylostoma
duodenale
 Fecal
Oral Route
 Penetration of filariform
larvae upon human skin
 Transplacentally and
through mother’s milk

Necator americanus
 Penetration
of filariform
larvae upon human skin
Hosts

Definitive Host
 Humans

(Children more commonly than adults)
Paratenic Host
 A.
duodenale can be transmitted through
ingestion of undercooked meat (rabbit, pork, beef,
lamb)
 Pigs can serve as a transport host for N.
americanus
Other Forms

Ancylostoma caninum
 dogs,
fox
 intestinal

Ancylostoma braziliense
 canines,
felines
 Cutaneous larval migrans

Humans act as accidental hosts for both
species
Pathogenesis

Cutaneous Phase:
 Occurs
when the juvenile penetrates human skin
 Ground Itch (“Creeping Eruption”)

Pulmonary Phase:
 Occurs
when juveniles break out of lung
capillaries and into the throat
 Usually asymptomatic
 Dry coughing or sore throat may occur
 Pneumonitis (Rare)
Pathogenesis

Intestinal Phase:
 Occurs
when worms reach the small
intestine and attach themselves
 Iron deficiency anemia:
 N.
americanus can suck approximately 0.03 L of
blood per day (1000 worms)
 A. duodenale can suck approximately 0.26 L of
blood per day (100 worms)
 Abdominal
Pain
 Loss of normal appetite
 Cognitive Impairments
Diagnosis

Eggs or Worms in Feces
 Must
use concentration
technique

Differentiating between N.
americanus & A.
duodenale:
 Use
PCR-RFLP method
Treatment & Prevention

Treatment:

Mebendazole- Drug of choice
Removes both species of Hookworm
 Single dose therapy is efficient and cheap


Prevention:
Education
 Persuasion of sanitary disposal of feces (use of
latrines)
 Avoid using nightsoil for fertilization
 Mass Drug Administration (Distributing Benzimidazole
Anthelmintic Drugs)

Public Health Concern


Approximately 22.1 million DALY’s (Daily
Adjusted Life Years) have been lost due to
Hookworm Infection
Research:
 Vaccines
currently being clinically tested for
targeting:
 Larval
worm stage
 Adult worm stage
References



http://www.cdc.gov/ncidod/dpd/parasites/hookworm/fact
sht_hookworm.htm
https://health.google.com/health/ref/Creeping+eruption
Roberts, Larry S. and Jr. John Janovy. Foundations of
Parisitology. 8th Edition. November 30th, 2008.