Vertical transmission of Toxocara canis in successive generations of mice

Abstract

Visceral toxocariasis is a neglected zoonosis caused by Toxocara canis larvae in unusual hosts. In dogs, the definitive host, the infection occurs mainly through transplacental and transcolostral transmission. Studies on experimental models have shown that vertical transmission may result from acute infections. Considering that toxocariasis is characterized as a chronic infection, with possible reactivation of larvae present in the brain, this study evaluated the presence of larvae in the brain of female BALB/c mice and their offspring with chronic infection during three successive pregnancies. ELISA-TES was used to evaluate the antibody levels. T. canis larvae were detected in the brain tissue of the mice during the three successive generations evaluated. The offspring's IgG level gradually decreased, and mean absorbance (ABS) above the cutoff point (0.070) was observed only at 30 (0.229) and 50 (0.096) days of age, while IgM was not detected. The infections in the offspring confirmed that vertical transmission of T. canis larvae occurred during chronic toxocariasis in three successive generations of mice.

The Seropositivity of Toxocara spp. Antibodies in Pregnant Women Attented at the University Hospital in Southern Brazil and the Factors Associated with Infection

“…cati in definitive hosts (dogs and cats) [ 39 ], and T . canis larvae in parathenic hosts demonstrate the capacity and tropism to migrate during pregnancy [ 40 – 41 ] or lactation to offspring, reinforcing the importance of conducting studies in this area in humans [ 42 – 43 ].…”

New insights into the immunopathology of early Toxocara canis infection in mice

“…In paratenic hosts, such as humans and mice, T. canis larvae do not develop to the adult stage but rather migrate throughout the somatic tissue and persist in the infectious L3 stage for extensive periods. In this context, experimental infection in mice, which mimics the biology of human infection, might be relevant to a better understanding of human toxocariasis [ 6 , 8 , 9 ]. Experimental T. canis infections in mice revealed elevated eosinophilia with high titers of IgE at 60 days after infection [ 15 ].…”

ELEVATED TRANS-MAMMARY TRANSMISSION OF Toxocara canis LARVAE IN BALB/c MICE

“…In addition to these well-documented transmission routes, in the last 50 years, several studies in experimental models have confirmed the vertical transmission of T. canis larvae 11 , 17 , 18 , 19 and one study evaluated and confirmed the trans-mammary transmission in ICR mice 10 . Almost two decades ago, ANDERSON (1996) had already warned about of the possibility of T. canis larvae be transmitted to the fetus when the mother acquires an infection during pregnancy; this event could lead to the development of the neurologic form in the affected child.…”

“…Simultaneously, three female and three male mice were mated. After giving birth, the females were intragastrically inoculated with 1200 embryonated T. canis eggs 19 . The animals were weaned after 21 days and were kept in their cages until they reached an age of 50 days.…”

“…In recent decades, several studies have been conducted to evaluate the vertical transmission of T. canis larvae in paratenic hosts 11 , 17 , 18 , 19 . The confirmation of T. canis trans-mammary transmission came only a few years ago with the observation of larvae in the brain of ICR mice nursed by females that had recently been infected with 300 eggs 10 .…”