Inclusion Criteria:  A child < 36 months old at the time of enrolment. A child presenting with diarrhoea (i.e. > 3 episodes of looser than normal stools in 24 hours) at a health facility within the study catchment area and in possession of a study ID number. Parents of eligible children, able to understand the study information and give informed consent by signature or thumbprint. (NB. illiterate participants will be able to give consent in the presence of an impartial witness) Children living within the study catchment area served by each participating health facility and in possession of a study ID number The parent/s who is willing to comply with all stipulated study procedures. Parents who are willing to allow their child to submit a stool sample for testing.  Exclusion Criteria:  Children presenting to the health facility without a study ID number Any child born after the Census has taken place Any child currently participating in the OEV124 study