Strongyloides spp and other parasites found on lettuce (Lactuca sativa) commercially available in the city of Recife, Brazil

Abstract

Natural vegetables, mainly lettuce (Lactuca saliva), are important vehicles for
the transmission of infectious parasitic diseases. This study tested the presence of
enteroparasites in commercial sources of lettuce cultivated through conventional,
organic and hydroponic methods in the city of Recife, Brazil. A total of 66 samples were collected, of which the following cultivation types were taken: 30 conventional,
30 organic, and 6 hydroponic. Parasites were detected by sedimentation through the
Hoffman, Pons & Janer (HPJ) method. Parasitological analysis detected parasites
in 88.8% and 100% of the lettuce collected, in supermarkets and fairs, respectively;
predominantly larvae of Strongyloides spp. Additionally, 4/6 vegetables cultivated
through hydroponics and bought at supermarkets tested positive for Strongyloides
spp. Other parasites were observed as well: Ancylostoma spp eggs (8.3%) were found
in samples grown through conventional and organic methods, while Entamoeba spp
cysts (2%) were observed in vegetables grown through conventional means and
collected from free standing markets. Data presented show that lettuce are below
the standards of normal consumption as by the Resolution 12/1978 of the National
Commission of Normal Dietary Standards, which was established to certify
the absence of contamination, e.g., parasites and larvae, in Brazil’s commercial
vegetable industry. The elevated presence of Strongyloides spp larvae demonstrate
the lack of hygienic and sanitary conditions in the irrigation of commercialized
lettuce. The results of this study also indicate the need for a better monitoring system of those commercial enterprises that sell consumable vegetables, as this could possibly result in better quality and hygiene of these products.