Larval migration ofToxocara canisin piglets and transfer of larvae from infected porcine tissue to mice

Abstract

Visceral larva migrans (VLM), caused by Toxocara canis larvae in humans, animals and birds, is now well documented throughout the world. Seven piglets were infected orally with 5 x 104 embryonated eggs and the migration and distribution of T. canis larvae in the tissues were evaluated. After artificial gastric juice digestion, larval yields at necropsy from different organs and muscles on days 1, 3, 7, 15 and 30 post-infection (DPI) revealed 3.05, 0.97, 0.21, 0.13, 0.05, 0.14% recovery from liver, lungs, heart, kidneys, skeletal muscles and brain tissues respectively, with a total of 2486 (4.97%) recovery from all tissues together. The highest number of larvae 1527 (3.05%) was recovered from the liver throughout the period (1-30 DPI), indicating a special affinity of larvae for the liver. Subsequently five mice were each infected orally with 5 g of infected pig liver and, after necropsy on 10 DPI, 20 +/- 3.62, 17 +/- 5.10, 3 +/- 1.26, 12 +/- 3.92 and 30 +/- 5.69 larvae were recovered from liver, lungs, heart, brain and muscles, respectively. Thus, primarily, the migratory potential and adaptation of T. canis larvae in porcine tissue was examined and, subsequently, their establishment in the second paratenic host, the mouse, has been successful. No influence of host sex on the migratory potential of T. canis larvae was observed. The related pathology caused by migratory larvae and its zoonotic significance through the consumption of raw or undercooked pork has been emphasized.

Seroprevalence of human toxocariasis in Andean communities from the Northeast of Lima, Peru

“…It is possible that other sources of contamination could be present there, such as domestic animals living together with the population. About this, some authors have mentioned the possibility of getting toxocariasis after eating raw or poorly cooked meat from some domestic animals such as chickens, pigs, sheep or cows 6,15,[22][23][24] .…”

Urticaria as Symptom of Parasite Migration Through the Biological Barriers

“…Usually, urticaria can be induced by multicellular or enteric parasites such as Anisakis simplex, larva migrans and currents, Giardia lamblia or cercarial dermatitis, but even protozoan blood parasites may induce urticarial reactions during unusual migration through a compact tissue [5, 15, 16, 19-21, 32, 41-43, 74-77]. Because the parasitic migration may be related to certain life cycle stages, also the parasitesrelated urticaria/dermatitis occurrence and its resolving after antiparasitic therapy could not necessarily agree with epidemiologic data [4,38,43,44,78,79]. Apart from the involvement of humoral mechanism such as complement system and antibody response, the active role of parasite in the urticaria-associated migration and accomplishing of life cycle can be manifested by eosinophil attraction [56,80].…”

“…Consequently, the type I allergic reaction takes at least 2 to 6 hours to be triggered by alive larvae, while the ingestion of lyophilized larvae, or its equivalent in antigen, does not induce clinical symptoms in sensitized individuals [42,43]. A similar scenario develops also within paratenic hosts during larvae migration in different visceral organs, like in case of Toxocara canis [44]. These data suggest that the development of allergic symptoms could be an active effect of parasites and not only a host defense reaction.…”

Parasites Induced Skin Allergy: A Strategic Manipulation of the Host Immunity

“…Consequently, the type I allergic reaction takes at least 2 to 6 hours to be triggered by alive larvae, while the ingestion of lyophilized larvae, or its equivalent in antigen, does not induce clinical symptoms in sensitized individuals [44, 45]. A similar scenario develops also within paratenic hosts during larvae migration in different visceral organs, like in case of Toxocara canis [46]. These data suggest that the development of allergic symptoms could be an active effect of parasites and not only a host defense reaction.…”