Occurrence of Toxoplasma gondii on Raw Leafy Vegetables in Gaza, Palestine

Toxoplasma gondii, a ubiquitous obligate intracellular parasite that can infect homeothermic animals, is one of the main pathogens causing foodborne diseases worldwide. In Gaza, Palestine, leafy vegetables are frequently eaten raw. The present study was carried out to investigate the occurrence of T. gondii oocyst in local leafy vegetables. Fifty samples each of six species of leafy plants sold in open-air markets, in supermarkets, and by retail sellers were randomly collected from March to August 2019, for a total of 300 samples. The samples were examined by light microscopy after flotation in Sheather's sucrose solution and by PCR assay of the pelleted samples. All suspect T. gondii oocysts were confirmed with a PCR assay. With the PCR assay of the pelleted samples, only 19 (6.33%) of the 300 samples were positive for T. gondii, whereas with the Sheather's flotation method, 35 (11.66%) of the 300 samples were positive. With the PCR assay, among the six plant types mint had the highest T. gondii prevalence (10.00% of samples) followed by watercress and dill (both 8.00%), parsley (6.00%), thyme (4.00%), and lettuce (2.00%). Even though the relative prevalence of T. gondii in the contaminated plant species was similar with both the PCR and Sheather's flotation methods, the actual prevalences were different. With Sheather's flotation, T. gondii prevalence was highest in mint (18.00% of samples) followed by watercress (14.00%), dill (13.00%), parsley (10.00%), thyme (10.00%), and lettuce (6.00%). The relationship between T. gondii contamination and the time of year the samples were collected was also significant. The highest prevalence recorded was in July followed by June and August. These findings indicate that leafy vegetables, particularly mint, can be contaminated with T. gondii and are a potential risk factor for transmitting T. gondii to humans in Gaza, Palestine.