Vertical transmission of Toxocara cati Schrank 1788 (Anisakidae) in the cat

Abstract

In eight cats and their offspring the mode of transmission of Toxocara cati following natural and experimental infection was investigated in three experiments. In experiments 1 and 2 the kittens of four cats with a chronic natural infection and of four cats with an acute experimental infection, respectively, were examined. In experiment 3 two queens of experiment 2 were mated again to examine whether in the adult cat "dormant" larvae exist in the tissue, that can be reactivated during pregnancy or lactation to infect the offspring. Additionally, the muscle tissue and organs of two adult cats, one with chronic one with acute infection, were examined for hypobiotic larvae. Pre-natal infections with T. cati did not occur in experiments 1 or 2. In none of the kittens that were examined directly after birth were larvae found. In the offspring of experiment 1 one single larva of T. cati was found 28 days post-partum. Whereas in the kittens of experiment 2 up to 333 larvae were found in one animal. Lactogenic transmission of larvae occurs after acute infection of the queen during late pregnancy but not during chronic natural infection. There is no evidence for the existence of arrested somatic larvae in the adult cat as an important host-finding strategy in the life cycle of T. cati. Following milk-borne infections, the majority of larvae seem to undergo direct development in the intestine without tracheal migration. Only a small number of larvae was found in other organs.

Prevention of Lactogenic Toxocara cati Infections in Kittens by Application of an Emodepside/Praziquantel Spot-on (Profender®) to the Pregnant Queen

“…To date it has been shown that lactogenic transmission of T. cati larvae occurs only after acute infection of the queen during late pregnancy and not during chronic infections (Coati et al 2004). …”

“…To mimic this situation, the infection protocol used by Coati et al (2004) and Wolken et al (2009) was successfully adopted in this study. Vertical infection was proven in 21 of 23 kittens in the control group.…”

“…Furthermore the recommendations given in VICH Guideline 7 "Efficacy of anthelmintics: general requirements" (November 2000), VICH Guideline 20 "Efficacy of anthelmintics: Specific Recommendations for Felines" (June 2001) and the WAAVP guidelines for evaluating the efficacy of anthelmintics for dogs and cats (Jacobs et al 1994) were followed whenever possible. The general study design was based on experience published in the scientific literature (Coati et al 2004;Wolken et al 2009). …”

“…These larvae invade the foetuses directly or accumulate in the mammary glands to be transmitted via the milk after parturition. While both ways of vertical transmission occur in bitches chronically infected with Toxocara canis, Toxocara cati has only been shown to be lactogenically transmitted after acute infection during late pregnancy (Coati et al 2004) (Fig. 1).…”

Alterações comportamentais em Rattus norvegicus experimentalmente infectados por Toxocara cati ou T. canis

“…No caso da transmissão de T. cati para felídeos não se conhece ocorrência da via transplacentária nem da ingestão de L5 (Coati et al, 2004;Sprent, 1956) Além disso, as larvas presentes na musculatura das fêmeas prenhes são estimuladas a migrar para o útero e glândulas mamárias, o que facilita a transmissão vertical desse parasito (Mattos-Junior, 1999;Sprent, 1956;Urquhart et al,1990).…”