Detection of Toxoplasma gondii oocysts in fresh vegetables and berry fruits

Abstract

Background: Toxoplasma gondii is the third most important contributor to health burden caused by food-borne illness. Ingestion of tissue cysts from undercooked meat is an important source of horizontal transmission to humans. However, there is an increasing awareness of the consumption of fresh fruit and vegetables, as a possible source for oocyst transmission, since this stage of the parasite can persist and remain infective in soil and water for long time. Herein, we outline findings related with detection of T. gondii oocysts in vegetables and berry fruits, which are usually raw consumed. The procedure includes the estimation of the number of oocysts. Methods: Food samples were collected from local producers and supermarket suppliers. Toxoplasma gondii oocysts were concentrated after washing the samples by applying high resolution water filtration and immunomagnetic separation (method 1623.1: EPA 816-R-12-001-Jan 2012), in order to (i) remove potential Cryptosporidium spp. oocysts and Giardia spp. cysts present in the samples; and (ii) select T. gondii oocysts. Toxoplasma gondii oocyst detection and an estimation of their numbers was performed by conventional PCR and real time qPCR, using specific primers for a 183-bp sequence of the T. gondii repetitive DNA region. All PCR-positive DNA samples were purified and sequenced. Restriction enzyme digestion with EcoRV endonuclease confirmed the presence of the T. gondii DNA fragment. In addition, the presence of the parasite was observed by fluorescent microscopy, taking advantage of the oocysts autofluorescence under UV light. Results: Forty percent of the analysed samples (95% CI: 25.5-56.5%) presented the expected PCR and digested DNA fragments. These fragments were confirmed by sequencing. Microscopic autofluorescence supported the presence of T. gondii-like oocysts. The estimated mean (± SE) oocyst concentration was 23.5 ± 12.1 oocysts/g, with a range of 0.6-179.9 oocysts/g. Conclusions: Our findings provide relevant evidence of contamination of fresh vegetables and berry fruits with T. gondii oocysts.

Recombinant Toxoplasma gondii Ribosomal Protein P2 Modulates the Functions of Murine Macrophages In Vitro and Provides Immunity against Acute Toxoplasmosis In Vivo

“…However, these parasites can cause severe disease, even leading to death in immunocompromised individuals [ 5 ]. According to previous reports, T. gondii can be spread by the ingestion of unsterilized meat and contaminated fruits, vegetables, and drinking water [ 6 , 7 , 8 ]. Moreover, the vertical transmission of T. gondii can cause irreversible damage to a fetus, miscarriage, and stillbirth; additionally, congenital deformities can occur [ 9 , 10 , 11 , 12 ].…”

Determination of the Occurrence of Toxoplasma Gondii, Giardia Duodenalis and Cryptosporidium spp. in leafy Greens in Marrakech using a Molecular Method

“…The present study revealed a high rate of T. gondii (29.6%) in leafy greens. The detection of this parasite has been reported elsewhere such as in Czech Republic 9.6% (28/292) [46] and Portugal and Spain 42.9% (14/35) [47], using molecular methods. In North Africa, only two studies have been conducted to investigate the presence of this parasite in fresh vegetables: the study performed in Egypt [15] has revealed using microscopy a contamination rate of 5.6 % (19/212), while our previous study [20] showed an overall rate of 21% (18/86), using the same qPCR.…”

Serosurvey of Anti-Toxoplasma gondii Antibodies in Homeless Persons of São Paulo City, Southeastern Brazil

“…Nonetheless, human toxoplasmosis outbreaks may be attributed to exposure to infected cats, which may indicate an important role of cat oocyst excretion on infection spreading (48,49), and homeless might be daily overexposed to environmental contamination. Another interestingly study has reported that 14/35 (40.0%) fresh vegetables and fruits collected from local producers and supermarket suppliers of Portugal and Spain were positive to T. gondii by PCR and microscopic autofluorescence (50). However, as mentioned above, homeless dietary habits of high intake of processed foods and low fresh meat, fish, vegetables and fruits may have led to lower T. gondii exposure.…”