The relationship between the presence of antibodies and direct detection of Toxoplasma gondii in slaughtered calves and cattle in four European countries

Toxoplasma gondii in cattle in Brazil: a review

“…On the one hand, the resistance to infection among cattle and difficulty in isolating T. gondii from these infected animals raise questions about whether this parasite is really present in cattle meat and what its real infective capacity among humans is, along with questions about the sensitivity of the diagnostic methods applied for detecting this protozoan in cattle (Burrells et al, 2018;Tenter et al, 2000). Although natural infections usually appear to be asymptomatic, presence of this coccidian in the viscera and tissues of these ruminants at the age of slaughter has been reported, under both experimental and natural conditions (Burrells et al, 2018;Costa et al, 2011;Dubey, 1992;Hosein et al, 2016;Macedo et al, 2012a;Opsteegh et al, 2019). Moreover, although quantification of the risk of transmission of this coccidian to humans through consumption of cattle beef is complex, this risk is real (Belluco et al, 2016;Opsteegh et al, 2011a).…”

“…Failure to isolate this protozoan in cattle may also be explained by difficulty in detecting T. gondii in tissues consequent to the limited size of the samples examined in these studies (Opsteegh et al, 2019). Especially in livestock animals, the low levels of parasitemia and wide dissemination of this coccidian, which has the capacity to infect any nucleated host cell, mean that it is possible that this parasite may be present in non-evaluated tissues.…”

“…Therefore, a negative result from a tissue fragment does not necessarily imply absence of T. gondii from the whole tissue (Esteban-Redondo et al, 1999;Santos et al, 2010). In this regard, Opsteegh et al (2019) found that cattle that tested positive in a bioassay (on the liver) tested negative in magnetic capture quantitative PCR (MC-PCR, on the diaphragm), and vice-versa. These authors also pointed out that the low T. gondii DNA concentrations revealed by qPCR on mouse brains and bovine diaphragms suggested that the numbers of parasites in the bovine liver and diaphragm are low (Opsteegh et al, 2019).…”

“…Because of the resistance to disease development that cattle present and difficulty in isolating this parasite from the tissues of infected cattle, the infective capacity of this protozoan in beef has been questioned (Dubey & Jones, 2008;Tenter et al, 2000). Additionally, there is great concern regarding the representativeness of negative results from tests for direct detection of parasites from tissue samples, given the limited size of these samples, especially considering the high potential for dissemination and low parasitemia levels of T. gondii (Esteban-Redondo et al, 1999;Opsteegh et al, 2019).…”

“…The role of meat intake in the transmission of T. gondii to humans remains unclear (Dubey & Jones, 2008). In fact, the presence of this protozoan or its DNA in bovine tissues has been reported in studies conducted under both natural and experimental conditions (Costa et al, 2011;Dubey, 1992;Hosein et al, 2016;Opsteegh et al, 2011aOpsteegh et al, , 2019. In addition, toxoplasmosis outbreaks caused by consumption of meat from infected cattle have been reported in the literature (Eduardo et al, 2007;Kean, et al, 1969).…”