NAME: Toxocara canis, Toxocara cati
SYNONYM OR CROSS REFERENCE: Toxocariasis, visceral larva migrans, larva migrans visceralis, ocular larva migrans
CHARACTERISTICS: Nematode, helminth, larvae are 400 µm X 20 µm; adults females are 5 to 18 cm long and adult males 4 to 10 cm long; eggs are about 85 µm X 75 µm with a thick brown shell
PATHOGENICITY: Two distinct larva migrans infection can occur: visceral larva and ocular larva migrans, both due to the systemic migration of the larval form of the helminth; visceral larva migrans is characterized by hypereosinophilia, hepatosplenomegaly, pneumonitis, fever, and hyperglobulinemia, symptoms depends on the site and extent of larval migration; ocular larva migrans (endophthalmitis) symptoms includes leukokoria, loss of vision in the affected eye, eye pain and strabismus. Disease is rarely fatal.
EPIDEMIOLOGY: Worldwide; eggs are ubiquitous in the soil wherever dogs and cats defecate; common in preschool children with a history of dirt-eating; ocular disease more common in school-age children; increasingly recognized in humans; T. canis infections are much more prevalent
HOST RANGE: Dogs and cats are the definitive hosts for T. canis and T. cati respectively; humans and other mammals are accidental hosts for both parasites
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: By direct or indirect transmission of eggs from contaminated soil to the mouth by eating raw, unwashed vegetables and dirt (children); may also be contracted by eating raw infected tissue such as the liver of chickens, sheep, cattle
INCUBATION PERIOD: Varies from weeks to months depending on the intensity of the infection. Eggs require 1-3 weeks incubation in optimal conditions to become infective.
COMMUNICABILITY: Not directly transmitted from person-to-person
RESERVOIR: T. canis in dogs; T. cati in cats
ZOONOSIS: Yes - disease transmitted by contaminated feces of dogs and cats
VECTORS: None
DRUG SUSCEPTIBILITY: Sensitive to antihelminths diethylcarbamazine, thiabedazole, mebedazole, albedazole
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde
PHYSICAL INACTIVATION: Eggs are sensitive to drying
SURVIVAL OUTSIDE HOST: Eggs can remain viable in soil for many months
SURVEILLANCE: Monitor for symptoms; confirm by ELISA testing, microscopic demonstration of eggs in tissue samples
FIRST AID/TREATMENT: Administration of appropriate drug therapy
IMMUNIZATION: None available
PROPHYLAXIS: None available
LABORATORY-ACQUIRED INFECTIONS: None reported to date
SOURCES/SPECIMENS: Blood and blood products; feces; ocular tissues
PRIMARY HAZARDS: Ingestion; contamination of mucous membranes; skin penetration of larvae
SPECIAL HAZARDS: Avoid the generation of aerosols when working with infected laboratory animals; avoid contact with contaminated feces
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment for activities involving the infective stage of the parasite, infectious body tissues and fluids
PROTECTIVE CLOTHING: Laboratory coats; gloves when skin contact with infectious materials is unavoidable
OTHER PRECAUTIONS: Good personal hygiene and frequent hand washing
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with absorbent paper towel and apply 1% sodium hypochlorite, starting at the perimeter and working towards the center; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate all wastes before disposal; steam sterilization, chemical disinfection, incineration
STORAGE: In sealed containers that are appropriately labelled
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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