A government health body has warned parents and teachers about an outbreak of dysentery at Jewish schools in Barnet, and urged them to exercise caution.

Public Health England (PHE) said there had been a “cluster” of cases “confined to one area” in the borough, but would not confirm locations or the numbers affected.

The testing of clinical samples confirmed the outbreak of dysentery, an intestinal infection which causes severe diarrhoea, with other symptoms including painful stomach cramps, nausea or vomiting, and a high temperature.

Dr Tania Misra, a Communicable Disease Control consultant, advised the Jewish community to be careful in a letter last week.

“The bacteria can cause large outbreaks of diarrhoea, particularly among young children,” she said. “The illness is usually spread from person to person when hands and food are contaminated with faeces from an infected person, facilitated by large social and/or religious gatherings, and travel.”

Misra added that children should not attend school “until they have been symptom-free for 48 hours,” and urged adherence to hygiene standards in food preparation and personal care.

“In addition to ritual hand washing, it is important that hands are washed thoroughly with soap and warm water after using the toilet, after changing children’s nappies and before preparing or eating food,” she said.

A PHE spokeswoman said it was “important to send out preventative messages to families and schools, to help stop further spread of infection and occurrence of further cases,” adding that any outbreaks of diarrhoea should be reported to the North East and North Central London Health Protection Team on 020 3837 7084 or necl.team@phe.gov.uk.