Use of antiviral prophylaxis in influenza outbreaks in long term care facilities.

Influenza is a major cause of illness and death in residents of long term care facilities for the elderly, in part because residents' age and underlying illness increase the risk of serious complications, and in part because institutional living increases the risk of influenza outbreaks. The administration of antiviral medications active against influenza to persons exposed to influenza has been shown to protect them effectively from illness, and mass antiviral prophylaxis of residents is an effective means of terminating influenza A outbreaks in long term care facilities. The only antiviral currently licensed in Canada for influenza prophylaxis is amantadine, a medication active against influenza A but not influenza B. The National Advisory Committee on Immunization recommends that amantadine prophylaxis be offered to residents when influenza A outbreaks occur in long term care facilities. However, there remain a number of unanswered questions about how best to use amantadine for controlling influenza A outbreaks in long term care facilities. In addition, two members of a new class of antivirals called neuraminidase inhibitors have recently been licensed in Canada for the treatment of influenza, and are effective in prophylaxis. Issues in the use of amantadine in the control of outbreaks of influenza A in long term care facilities for the elderly are reviewed, and the potential uses of neuraminidase inhibitors in this setting are discussed.

Pandemic planning in Canada.

A Canadian plan for pandemic influenza was completed by the National Advisory Committee on Immunization in 1988. Its development took several years and involved consultation with provincial public health and laboratory authorities, the licensing body, manufacturers of influenza vaccine and antiviral agents, and representatives in the USA and UK. Key decisions in creating the pandemic plan include: (1) aiming for federal-provincial consensus on use of vaccine and antiviral drugs, (2) a selective vaccination approach (high-risk persons plus essential workers), (3) bulk purchasing and distribution of vaccine through the public sector, (4) leaving antiviral drugs on the open market, (5) careful planning of the communications strategy, and (6) increasing inter-pandemic use of flu vaccine in target groups. The plan addresses recognition of a pandemic; activation of a Pandemic Influenza Committee whose membership and responsibilities are spelled out; the federal-provincial decision making process; influenza vaccine considerations; amantadine and other antiviral agents; estimates of target group size, vaccine uptake, manufacturing capabilities and time frames; and communication considerations. Since 1988, influenza vaccine use has increased considerably in Canada and experience has been gained with amantadine. Manufacturing capability within Canada for influenza vaccine has also been enhanced. It is now time to update the plan, especially the targets, and to make sure that everyone involved remains aware of the assigned roles.

The prevalence, incidence, geographical distribution, antimicrobial sensitivity patterns and plasmid profiles of milk filter Salmonella isolates from Ontario dairy farms.

The prevalence, incidence and geographical distribution of Salmonella on dairy farms in southwestern Ontario were determined by culturing bulk milk filters from 511 randomly selected dairy farms. Milk filters from 22 farms (2.9%) were Salmonella-positive, with a cumulative incidence rate of 9.0% per year. Positive farms were distributed throughout southwestern Ontario, but were regionally clustered. The serotype, biotype, antimicrobial sensitivity pattern and plasmid profile of the Salmonella isolates from six farms where Salmonella were recovered on two occasions were identical. All of the Salmonella strains isolated were sensitive to commonly used antimicrobials.