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) Eggs: 56-60 μm by 35-40 μm, thin shelled

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/hookwor

m/factsht_hookworm.htm https://health.google.com/health/ref/Creeping+er

uption Roberts, Larry S. and Jr. John Janovy. Foundations

of Parisitology. 8th Edition. November 30th, 2008.