Consequences of the Infection of Children with the Eggs of the Toxocara canis Parasite

and Preventative Measures.

TURFAH MauloodGroup: 6

Outlines - Introduction-Life cycle-Disease in humans:• 1-Visceral Larvae Migrans (VLM): • a- Respiratory, Hepatic and Cardiac forms • b- Central Nervous System• 2-- Ocular Larva Migrans (OLM)-Epidemiology and risk factors-Preventative measures-Conclusion-References

Introduction

Causative agent : Toxocara canis

Infected animals: All canids

Modes of transmission:

-In dogs: paratenic hosts, contaminated food

-In humans: fertilised eggs

Figure 1: Shows A- Adult Toxocara spp. B- Picture of adult parasite by electron

Microscope. (Courtesy of the Centre for Disease Control and Prevention)

Life cycle:

Figure 2: Diagram of the Toxocara canis life cycle. (Courtesy of the Centre for Disease Control and

Prevention).

Disease in humans

1-Visceral Larvae Migrans (VLM):

a- Respiratory, Hepatic and Cardiac forms

b- Central Nervous System

2- Ocular Larva Migrans (OLM)…………………………………………………………

Figure 3: A child infected by OLM. (Courtesy of the Centre for Disease Control and prevention).Epidemiology and risk factors:

The Netherlands 19% USA 14% Germany 2.5% The Slovak Republic 13% Brazil 39% The Czech Republic 5.8-36% Spain 0-37% Cuba 5.2% Jordan 10.9 % Colombia 47.5% Nepal 81%

Figure 4: The map shows distribution of the parasite . (Courtesy of the Centre for Disease Control and prevention).

Preventative measures• 1- Deworm pet dogs, pregnant bitches with anthelminthic regularly.

• 2- Eradicate and control stray dogs

• 3- Do not consume any food or water that may have been contaminated by

T.canis eggs.

• 4- Clean the dog living area regularly, all defective matter should be buried.

• 5- Restrict playing of children in outdoor environment, especially children

suffering from pica.

• 6- Teach children the importance of washing hands frequently.

Conclusions • Toxocara canis is a worldwide distributed parasite. • Infect primarily dogs.• Dogs can be infected by eating paratenic hosts or other contaminated foods.• Cause a disease known as Toxocariasis in humans.• Humans are infected by eating contaminated vegetables or direct ingestion of

eggs.• Larvae migrate to different target organs causing VLM and OLM.• Symptoms depend on the organs involved.• The most effective preventative measures are: drenching of dogs and increase

the level of awareness.

References• Anderson, A., Fordhman, L.A., Bula, M.L., and Blat, J. (2006) ‘ Visceral Larva Migrans masquerading as metastatic disease in toddler with Wilms tumour’ Pediatr

Radiol, vol.36, pp.265-267.

• Bachli, H., Mint, J.C. and Gratzl, O. (2004) ‘Cerebral Toxocariasis: a possible cause of epileptic seizure in children’, Childs Nerv Syst, vol.20, pp.408-472.

• Bell, R.D. (1995) Lecture Notes on: Tropical Medicine. 4th edition, Oxford: Blackwell science Ltd.

• Centre for Disease Control and Prevention. (2013) ‘Toxocariasis: prevention and control’, [Online], Available: http://www.cdc.gov/parasites/toxocariasi [Accessed: A07/02/2014].

• Fan, C.K., Hung, C.C., Du, W.Y. Liao, C.W., and Su, K.E. (2004) ‘Seroepidemiology of Toxocara canis infection among mountain Aboriginal schoolchildren living in contaminated districts in eastern Taiwan’, Tropical Medicine and International Health, vol.9, no. 11, pp. 1312-1318.

• Good, B, Holland, C.V., Tylor, M.R.H., Larragy, J., Moriarty, P., and O’Regan, M. (2004), ‘Ocular Toxocariasis in schoolchildren’ , Clinical Infectious Diseaeses, vol.29, no. 2, pp.173-178.

• John, D. and Petri,Jr. W. (2006) Medical Parasitology, 9th edition, Missouri: Saunders Elsevier.

• Pinelli E, Herremans T, Harms MG, Hoek D, Kortbeek LM. (2011)’ Toxocara and Ascaris seropositivity among patients suspected of visceral and ocular larva migrans in the Netherlands: trends from 1998 to 2009’. Eur J Clin Microbiol Infect Dis, vol.30, no.7, p.873-879.