WHO puts Toronto back on SARS transmission list

WHO puts Toronto back on SARS transmission list

The United Nations health agency has put Toronto, Canada, back on the list of areas with recent local transmission of Severe Acute Respiratory Syndrome (SARS) following new reported clusters of 26 suspect and eight probable cases of the deadly disease linked to four area hospitals.

The announcement yesterday by the World Health Organization (WHO) did not include a new recommendation for travel restrictions to Toronto. The agency had removed the city from the local transmission list on 14 May after 20 days had passed since the last isolation of a locally acquired case of SARS. It had also lifted its advisory against non-essential travel to Toronto after an improved outlook there on 30 April.

Canada has a cumulative case record of 148 suspected infections with 26 deaths. Worldwide, SARS has infected 8,202 with 725 deaths as of Monday.

Although results of laboratory and epidemiological investigations are pending, sufficient information is available to determine that the index, or first, case in the present outbreak has transmitted infection to others in more than one generation of local transmission, WHO said. Toronto is therefore classified as having “pattern B” transmission. This is defined as more than one generation of local probable SARS cases.

Inclusion of countries and areas in this list does not mean that WHO recommends travel restrictions to the country or area, and the agency said it was not at present recommending any restrictions on travel to Toronto.

Local transmission of SARS is of greatest concern, in terms of risks to both local populations and international travellers, when a new case cannot be traced back to contact with another case, or turns out to have been a contact of a case but was not placed in isolation. Both situations increase opportunities for local spread to others.