Occurrence of (oo)cysts of Cryptosporidium and Giardia on vegetables across Nepal

Gastrointestinal disorder caused by the ingestion of (oo)cysts of Cryptosporidium and Giardia is one of the major health problems in developing countries. Fruits and vegetables that are usually consumed unpeeled, poorly washed and or cooked and are the major modes of transmission. Frequent large-scale screening of the food samples is necessary to prevent outbreaks but screening of vegetables for such microbes is limited in Nepal. In this study, we used a smartphone microscopy system to study prevalence and quantification of (oo)cysts of Cryptosporidium and Giardia in 651 vegetable samples collected from nine major vegetable collection sites across Nepal. The overall prevalence rate of vegetable samples was 37.5% with at least with one of the parasites. We found that 23.2% samples were contaminated with Giardia and 33.3% samples were contaminated with Cryptosporidium. Among eight vegetable types, the prevalence rate was lowest in carrot (20%) and highest in spinach (48%). The prevalence rate of vegetable samples at different sites ranged from 13% in Dhading to 61% in Dhangadi. The contamination rate was 28% for winter, 43% for summer and 33% for monsoon seasons in samples collected from Kathmandu. These vegetables should be considered as a potential source of parasitic contamination in people. These vegetables can cause infection if consumed poorly washed and or cooked, posing a potential source of parasitic contamination in people.