HOOKWORM DISEASE

GENERAL INFO

• A species of hookworm that causes soil-transmitted helminth
• Affects mammals such as humans, dogs, and cats
• One of the worlds most important cause of physical and intellectual growth retardation
• Most common parasitic roundworm in the world
• Helminths are parasitic worms that cause a wide variety of infectious diseases

BIOLOGY

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REPRODUCTION

• Sexual maturity is reached at the final molt,
• Egg production occurs 5 weeks after female matures
• Mating occurs in the intestine of the host
• Males are required to find females and inject their sperm into the female
• Females can produce 10,000 eggs per day, and eggs are passed out along feces

DEVELOPMENT/GROWTH

• 1st & 2nd stage of Rhabditiform larvae are free-living
• 3rd stage of filariform larva & comes in contact with host skin
• 3rd stage larva migrates to intestines, molt and adult will emerge
• Adult attaches to inner wall of intestine & cause hemorrhage
• From hemorrhage, adult feeds off the blood

DEVELOPMENT/GROWTH

• Mating occurs in intestine
• Eggs are expelled along feces
• Adult worms can live up to 5 years

STRUCTURE

• Range length 7 to 11 mm
• Cylindrical body & a cuticle with 3 main outer layers
• Has 2 dorsal & 2 ventral cutting plates
• A pair of subdorsal teeth & a pair of subventral teeth

COMMUNICATION & PERCEPTION

• Females produce pheromones to attract males
• Setae and amphids: sense organs
• Setae detects motion
• Amphids detects chemicals

FOOD HABITS

• Worm attaches to intestinal wall
• Use its cutting plates to cause bleeding
• Feed from the blood of their hosts

CHEMISTRY

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• Cytokine and exsheathment enzymes used to penetrate skin
• Glutathione S-transferases critical for parasite blood feeding & survival
• Hookworms release considerable amounts of acetylcholinesterase
• Acetylcholinesterase affects the host's immune system

Mitochondrial genome

• It encoded 12 proteins
• 2 ribosomal RNA
• 22 transfer RNA genes
• but lack the ATP synthetase subunit 8 gene

TREATMENT

• Can be treated with combinations of:
• -benzene (organic compound)
• -Imidazole (organic compound)

ENVIRONMENTAL SCIENCES

CLIMATE INFLUENCES

• N. americanus is found in tropical climates
• Eggs require a moist, warm and shaded environment to hatch
• Eggs and juveniles die below freezing or with dry soil
• Heavy rains/warm temp. = high positive correlation rate of transmission

ENVIRONMENT ISSUES

• Poverty-stricken areas with poor sanitation are prominent with high infection rates
• Locations such as:
• -the Americas, Sub-Saharan Africa, Southeast Asia, China, and Indonesia
• Are prominent locations for N. Americanus

AS A RESULT

IT AFFECTS

• The people in the tropical locations and developing countries
• Hookworm is a leading cause of maternal and child morbidity
• In children, hookworm causes :
• -intellectual, cognitive and growth retardation
• intrauterine growth retardation, prematurity, and low birth weight

ILL EFFECTS

• Nutrition and blood loss are the major contributors to ill effects
• Severe case scenarios include:
• -iron deficiency
• -anemia
• -weight loss

MORBIDITY CONTROL

• Public health activities are focussed on reducing hookworm's impact
• There is an increasing call for STH control programs
• STH = soil-transmitted helminth

QUICK FACTS

...WHAT?

• An estimated 44 million pregnant women that are infected world wide!
• It is estimated that up to one-fifth of the world's population is infected with hookworms
• Humans do not develop an immunity to hookworm infection
• Each hookworm consumes approximately0.03 to 0.15 milliliters of blood each day
• Hook-worm disease can causes impotency in men

REFERENCES

• http://gastrointestinal-conditions.knoji.com/facts-about-hookworms/
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC89000/
• http://www.ncbi.nlm.nih.gov/m/pubmed/11812491/
• http://onlinelibrary.wiley.com/doi/10.1111/j.1432-1033.1994.tb19943.x/abstr...
• http://animaldiversity.ummz.umich.edu/accounts/Necator_americanus/#predatio...

REFERENCES

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2849424/
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929050/