Necator americanus

Necator americanus

MATERIAL SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Necator americanus

SYNONYM OR CROSS REFERENCE: Hookworm disease, necatoriasis

CHARACTERISTICS: Family Ancylostomatidae, subfamily Necatorinae; intestinal nematode parasite, adult male measures 5-9 X 0.30 mm, female 9-11 X 0.35 mm; eggs are 64-76 X 35-40 µm head curves opposite to curvature of body, giving a hooked appearance to the anterior end

SECTION II - HEALTH HAZARD

PATHOGENICITY: Infective larvae penetrate skin and travel via the lymphatics to enter the bloodstream, the lungs and the small intestine; adult parasites attached to the villi of small intestines suck blood causing abdominal discomfort, diarrhea, cramps, anorexia, weight loss; clinical features correspond mainly to the intensity of infection; heavy infection leads to development of iron deficiency and hypochromic microcytic anemia;leading causes of iron-deficiency anemia in children resulting in physical and mental retardation in development; infection causes cutaneous larva migrans - a self-limiting condition characterized by skin eruption; fatality is rare; no evidence of immunity in the infected

EPIDEMIOLOGY: Widely in tropical and subtropical countries, where improper disposal of human feces is practiced; occurs in South East Asia, South Pacific and East Africa and South America - moisture and temperature conditions favour development of larvae; sporadic cases occurs in southeastern US; prevalence higher in rural areas; universal susceptibility

HOST RANGE: Humans

INFECTIOUS DOSE: Not known

MODE OF TRANSMISSION: Infective larvae, develop from eggs excreted in feces and penetrate the skin, usually by the dorsum of the bare feet or between the toes; vertical transmission from mother to child is possible

INCUBATION PERIOD: Variable; GI symptoms can appear 35-40 days after exposure to filariform larvae

COMMUNICABILITY: Not directly transmitted from person-to-person

SECTION III - DISSEMINATION

RESERVOIR: Humans

ZOONOSIS: None

VECTORS: None

SECTION IV - VIABILITY

DRUG SUSCEPTIBILITY: Sensitive to abendazole, mebendazola, pyrantel pamoate, levamisole

DRUG RESISTANCE: Mebendazola resistant strains have been reported

SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde

PHYSICAL INACTIVATION: Larvae sensitive to desiccation and freezing

SURVIVAL OUTSIDE HOST: Larvae can survive up to 3-4 weeks in moist, optimal survival in moist, sandy or loamy soil with ambient temperatures of 24-32° C

SECTION V - MEDICAL

SURVEILLANCE: Monitor for symptoms: confirm by microscopic demonstration of eggs in stools

FIRST AID/TREATMENT: Administer appropriate drug therapy; pregnant women should not be treated with drugs in the first trimester

IMMUNIZATION: None available

PROPHYLAXIS: None available

SECTION VI - LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: None reported to date

SOURCES/SPECIMENS: Feces

PRIMARY HAZARDS: Ingestion; droplet exposure of the mucous membranes

SPECIAL HAZARDS: None

SECTION VII - RECOMMENDED PRECAUTIONS

CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment equipment for all activities involving the parasite, infectious or potentially infectious body fluids or tissues

PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious materials is unavoidable

OTHER PRECAUTIONS: None

SECTION VIII - HANDLING INFORMATION

SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover the spill with absorbent paper towel and apply 1% sodium hypochlorite, starting at the perimeter and working towards the centre; allow sufficient contact time (30 mins) before clean up

DISPOSAL: Decontaminate all wastes before disposal; steam sterilization, chemical disinfection, incineration

STORAGE: In sealed containers that are appropriately labelled

SECTION IX - MISCELLANEOUS INFORMATION

Date prepared: March, 2001

Prepared by: Office of Laboratory Security, PHAC

Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright © Health Canada, 2001

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