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Health Protection and Promotion Act
Loi sur la protection et la promotion de la santé

ONTARIO REGULATION 199/03

CONTROL OF WEST NILE VIRUS

Consolidation Period: From June 19, 2009 to the e-Laws currency date.

Last amendment: O. Reg. 241/09.

This Regulation is made in English only.

Determination if action required

1. A medical officer of health shall make a determination whether action is required by a municipality to decrease the risk of West Nile Virus to persons either inside or outside the health unit served by the medical officer of health, based upon a local risk assessment. O. Reg. 231/03, s. 1; O. Reg. 322/04, s. 1; O. Reg. 413/06, s. 1; O. Reg. 422/07, s. 1; O. Reg. 229/08, s. 1; O. Reg. 241/09, s. 1.

Notice to municipality

2. (1) Where the medical officer of health has determined that action is required, he or she may give notice to the municipality of the required action. O. Reg. 199/03, s. 2 (1).

(2) In determining required actions under subsection (1), the medical officer of health shall have regard to,

(a) the guidelines published by the Minister under section 7 of the Act; and

(b) the generally accepted practices in the field of public health with regard to decreasing the risk of West Nile virus to persons. O. Reg. 199/03, s. 2 (2); O. Reg. 241/09, s. 2.

Must comply

3. A municipality shall comply with any requirements set out in the notice. O. Reg. 199/03, s. 3.

What may be required

4. Action required under this Regulation may include, without being limited to,

(a) requirements respecting source reduction measures;

(b) requirements respecting surveillance;

(c) requirements respecting public awareness campaigns about personal protection;

(d) requirements respecting the control measures for larviciding and adulticiding set out in Table 1; and

(e) requirements respecting the time within which the action shall be taken. O. Reg. 199/03, s. 4.

TABLE 1
LARVICIDING AND ADULTICIDING IN ONTARIO — WEST NILE VIRUS RESPONSE

“Triggers” based on surveillance of WNv positive humans, birds, mosquito pools or mammals (horses)

Current-Year WNv findings in Health Unit or municipality

Last Year’s WNv findings in Health Unit or municipality

Preparatory Status (Larval surveys, mosquito trapping, mapping, training, etc.)

Larviciding ACTION

Adulticiding ACTION

No West Nile virus found yet

No West Nile virus found; virus found in adjacent Health Unit(s)

Not yet done

Do the preparatory work, then larvicide where indicated

Not indicated

No virus found yet

Virus found

Not yet done

Do the preparatory work, then larvicide where indicated

Not indicated

No virus found yet

Virus found

Done last year and under way this year

Larvicide where indicated

Not indicated

Virus found in non-human (dead bird, mosquito pool or mammal) — isolated or as a “hot spot”

Virus found or not found

Done or under way this year

If a “hot spot” and larvae are present, larvicide around this “hot spot” (if not too late in the season)

Adulticide a 3-km “Zone” ONLY IF there are high-risk indicators of transmission to humans*

Human case(s) — one or a few in a space-time “cluster”

Virus found or not found

Done or under way this year

Larvicide around the case or cluster if larvae are present (and if not too late in season)

Adulticide a 3-km radius Zone around the case or cluster

Human cases continue to occur; continued high-risk indicators*

Virus found or not found

Done or under way this year

Larvicide widely where larvae are found (if not too late in season)

Adulticide 3-km Zones — may be contiguous or overlapping

Note: Public education efforts and non-pesticide means of mosquito source reduction should be in place, and increased as increasing evidence of virus is found (especially human cases) in the current year.

* High-risk indicators of transmission to humans: increasing dead bird sightings; high mosquito infection rates; abundant bridge vector populations; increasing mammal (horse) cases; proximity of mosquito breeding sites to human populations (especially large population centres) and weather conditions that favour mosquito breeding.

1. These are minimum activity standards. Medical Officers of Health may increase the Zone size to be treated or take additional mosquito control actions, if justified by scientific data or recommendations.

2. Medical Officer of Health will maintain a means to record, investigate, and report any confirmed or likely adverse or unintended human health effects attributed to mosquito control actions, and will report any non-human environmental adverse effects that he or she knows about to the Ministry of the Environment and/or other relevant local or provincial authorities.

O. Reg. 199/03, Table 1.