October 1, 1998

To:Board of Health

From:Dr. Sheela V. Basrur

Subject:Cyclospora Outbreak in Spring 1998

Purpose:

To provide the results of the investigation of a major cyclospora outbreak in Toronto spring 1998 and make recommendations on the prevention and control of further outbreaks of cyclospora.

Source of Funds:

Not applicable.

Recommendations:

It is recommended that:

(1)The Ontario Minister of Health make cyclosporiasis a reportable disease in Ontario;

(2)The Federal Minister of Health make cyclosporiasis a reportable disease in Canada and put in place mechanisms for active surveillance of important foodborne diseases such as cyclosporiasis;

(3)The Ontario Minister of Health recommend that laboratories in Ontario routinely test for cyclospora oocysts in stool specimens submitted for ova and parasites;

(4)Toronto Public Health continue to increase awareness and knowledge about foodborne illnesses by providing relevant and timely information to health care providers and the public;

(5)Health Canada, in conjunction with Agriculture and AgriFood Canada (AAFC) and the Canadian Food Inspection Agency (CFIA), conduct further basic and applied research on the biology and epidemiology of cyclospora, e.g. mechanisms by which contamination occurs, effectiveness of control measures during high produce production periods;

(6)Health Canada and the CFIA develop a coordinated approach to the development of policies regarding importation of fresh produce which includes:

(a)a more vigilant and rigorous approach, erring on the side of public health and safety;

(b)comprehensive risk assessment, including review of relevant international epidemiological data and studies conducted by other health agencies; and

(c)work in partnership with the U.S. as appropriate;

(7)Toronto Public Health continue to actively participate in discussions re the spring 1999 policy for Guatemalan raspberry importation, and take the position that there should be a restriction on these imports until:

(a)further information is available from Guatemala on the farm tracebacks from the 1996, 1997 and 1998 outbreaks;

(b)more is known about the mechanism of contamination with cyclospora; and

(c)there is independent audit evidence of compliance by individual farm with the Model Plan of Excellence (MPE);

(8)The Board of Health express support for and interest in participation in the development of a coordinated and coherent foodborne outbreak investigation protocol at the federal level by Health Canada, AAFC and the CFIA, in consultation with health and agricultural authorities at the provincial and municipal levels;

(9)CFIA ensure that their inspectors receive training in doing comprehensive food traceback investigations as per the Centers for Disease Control & Prevention (CDC) protocol;

(10)The Ontario Minister of Health provide increased funding for the Public Health Branch to provide strong support and coordination in multi-regional and province-wide outbreaks;

(11)The Ontario Minister of Health provide continued funding for the Central Public Health Laboratory to enhance research and investigative abilities re foodborne pathogens and provide opportunities to liaise with international counterparts;

(12)The Ontario Minister of Agriculture, Food and Rural Affairs invite a municipal public health representative to join the newly-formed Steering Committee to develop a Food Safety Strategy for Ontario;

(13)Health Canada and the CFIA amend federal health protection legislation with respect to potential foodborne illnesses to permit them to take health protective actions based on "reasonable and probable grounds" and afford protection from personal liability for any act "done in good faith" (i.e. similar to the Ontario Health Protection & Promotion Act);

(14)Health Canada, in consultation with the CFIA, conduct an investigation to establish the mode of cyclospora contamination in raspberries;

(15)The CFIA examine the feasibility of requiring the implementation of preventive and control measures such as those contained in the MPE to all imported and domestically grown produce (based on the fact that such measures are not specific to raspberries or cyclospora and would contribute to the overall minimization of the risk of contamination of other food-borne pathogens);

(16)The CFIA consult with stakeholders including the general public, and health and environment agencies at the local, provincial and federal level to develop the position paper on the development of a Code of Practice for the production, harvesting and packaging of fresh fruits and vegetables for the CODEX Alimentarius Commission;

(17)The Medical Officer of Health review the health and environmental impacts of available food treatment technologies and assess their effectiveness in eliminating foodborne pathogens;

(18)The federal Minister of Agriculture and Agrifood and the provincial Minister of Agriculture, Food and Rural Affairs amend the Canadian Agricultural Products Act, the Consumer Packaging and Labelling Act, and the Ontario Farm Products Grade and Sales Act regarding country of origin labelling for all fresh and cooked fruits and vegetables sold at wholesale, retail or in clerk-served operations to ensure consumers can always acquire information about the origins of the food they are consuming. In making these amendments, the federal and provincial ministers should ensure that their respective amendments cover all possible purchasing scenarios;

(19)The federal Minister of Agriculture and Agrifood and the provincial Minister of Agriculture, Food and Rural Affairs increase the number of staff available to do enforcement work, particularly concerning country-of-origin labelling at retail to the public.

Background:

At its meeting on June 23, 1998, staff provided a verbal update on the recent cyclospora outbreak. The Board of Health requested that the Medical Officer of Health report back with:

(1)Recommendations on how to reduce this and any further outbreaks of cyclospora;

(2)Recommendations that would require fresh produce to be labelled as to its source and country of origin; and

(3)Possible recommendations on banning the importation of Guatemalan raspberries.

Comments:

A large outbreak of cyclosporiasis in Ontario in the spring of 1998 is described.

This outbreak is an example of "food as the next public health challenge"¹⁹ and the changing epidemiologic characteristics of foodborne disease in North America. Several factors have contributed to these changes:¹³

(1)Changes in Diet: substantial alterations in North American diet over the past two decades. Although the promotion of a "heart-healthy" diet (high consumption of fruits and vegetables and low consumption of fat) may be improving cardiovascular health, it has led to a new range of problems for the gastrointestinal tract.

(2)Globalization of Food Supply: Although locally grown produce can be a source of pathogens, fruits and vegetables from developing countries are cause for additional concern. Many developing countries are just entering the global produce market and yet comprise a significant percentage of produce consumed in North America.

(3)Emerging/Re-emerging Infectious Agents: When an emerging foodborne agent is first recognised, there are usually many unanswered questions about the biology, epidemiology and prevention of the infection. Health care providers need to be aware of the clinical presentations associated with new agents. Clinical laboratories need to be proficient at performing routine examinations for a wide variety of emerging agents. Public Health officials need to initiate and maintain population-based surveillance for these types of agents.

New food borne pathogens have emerged over the last decade. Many of these cannot be detected, while others can be detected and identified but with difficulty. Other microorganisms, previously thought to be innocuous, have emerged as more virulent. Food borne pathogens are increasingly overcoming time-tested controls, such as heating and refrigeration, and are developing new virulence and new ways to evade our immune defences.

Newly recognized pathogens are causing serious disease outbreaks. Diffuse and widespread outbreaks, involving many cities, provinces/states and even countries, are identified more frequently and follow an entirely different pattern than the classic foodborne outbreak.¹⁷

Factors influencing the emergence and re-emergence of "new" pathogens and "old" pathogens are numerous and reflect an interplay of biological and sociological forces (see Appendix 1).¹⁸ These kinds of infections demand new control strategies that start right at the farm level. A variety of major initiatives are being developed in the area of food safety (see Appendix 1).

Cyclosporiasis:

Cyclospora cayetanensis is a parasite that causes gastroenteritis. It is not spread directly from person to person but can be spread via contaminated food or water. Unfortunately there is no reliable test for detecting or monitoring cyclospora on foods. In some countries the infection appears to be seasonal, with most cases occurring from April through August. Appendix 2 provides more detailed information on symptoms, diagnosis, modes of transmission etc.

Cyclosporiasis is not designated as a reportable disease to public health authorities in Ontario or Canada at the national level. Thus the numbers reported to public health significantly underestimate the true numbers. Figure 1 presents the number of cases confirmed by the Ontario Central Public Health Laboratory (Ontario Ministry of Health) for the period January 1994 to July 23, 1998 (note that this does not include data from private labs). The number of cases reported to the old City of Toronto for 1997 was 17; data for the other parts of Toronto are unavailable.

Previous Outbreaks of Cyclosporiasis in North America:

Before 1996 most documented cases occurring in North America were in overseas travellers. Outbreaks linked to contaminated water and various types of fresh produce have been reported in recent years: ^{3, 4, 9, 11}

(1)spring 1996, total of 1465 cases (including 725 associated with 55 clusters/events) reported by 20 states, District of Columbia and 2 provinces (Ontario and Quebec). After a thorough investigation fresh Guatemalan raspberries were ultimately implicated as the vehicle of the outbreak.⁹

(2)spring 1997, total of 1012 cases (including 762 associated with 41 clusters/events) reported by 13 states, the District of Columbia and Ontario (31 cases in York Region). After a thorough investigation fresh Guatemalan raspberries were implicated as the vehicle of the outbreak in the US; results were inconclusive for the Ontario outbreak. The outbreak stopped after exportation of Guatemalan raspberries was voluntarily suspended at the end of May 1997.¹⁰

(3)spring 1997 outbreak in Florida linked to non-Guatemalan mesclun lettuce.

(4)early summer 1997 outbreak in Northern Virginia-District of Columbia- Baltimore, Maryland, Metropolitan area linked to basil.⁴

Guatemalan Raspberry Imports:

Guatemala has developed an export market for raspberries (and blackberries) over the last decade. Raspberries were introduced in Guatemala in 1987 and first exported in 1988. Exports increased thereafter, with the United States being the primary market for fresh raspberries.

Raspberries are grown as annuals and harvested on a six-month cycle. Exports peak in May and June (during the rainy season) and October through December (the dry season).

Appendix 3 provides a summary of berry imports (raspberries, blackberries, mulberries and loganberries) into Canada from all countries, which indicates that the amount of all berries imported from Guatemala has increased annually since 1995. As well, Appendix 3 shows that the majority of Guatemalan berries coming into Canada enter via Ontario. Spring shipments of Guatemalan raspberries start to pick up in late March and go to mid-June; fall shipments arrive mid-September to the end of December.

Mode of Contamination:^{10, 15, 16}

At this time, neither the specific source nor the point at which contamination of the raspberries occurred is clear. The potential sources of contamination are soil, potable water, human contact and animals. Some animals have been shown to be carriers of some species of cyclospora. Despite previously published reports suggesting animals, specifically birds, as cyclospora reservoirs, tests conducted by the CDC on a limited number of birds in Guatemala found them not to be infected.

The leading hypothesis for the mode of contamination implicates agricultural water used to mix insecticides and fungicides sprayed directly onto raspberries, sometimes as late as the day they are picked. Given that the raspberries are grown in hedgerows where the plants are 4-5 feet off the ground, routine irrigation, known as drip irrigation, is not implicated because direct contact between raspberries and the water is avoided (in drip irrigation the underside of the tubing has small holes so that the ground can be wet slowly over a long period). Other than when raspberries are fumigated, there is no contact with water through washing because raspberries are harvested dry due to a high degree of susceptibility to mould growth.

The following quote summarises the rationale that is being used to support the hypothesis relating to the potential mode of contamination.

"No single packing or storage facility in Guatemala, exporter, type of shipping container, shipment, airline carrier, U.S. port of entry or cargo-clearance area, importer, distributor, retailer, or food handler was linked to all 29 events for which we had good data about the source of the implicated raspberries. We concluded that some practice or attribute common to multiple farms was the most likely explanation for the outbreak."⁹

According to the CDC, one of the limitations with determining the mode of contamination is the lack of availability of sensitive techniques to detect very low parasite levels.¹⁰ The US Food & Drug Administration (FDA) advised that the analytical challenge is related to removing the organism from the raspberry.⁽¹⁵⁾ Raspberries have very rough surfaces with hair-like cilia that keep cyclospora on the surface (in comparison, blackberries have a smooth surface without cilia and have not been implicated in a cyclospora outbreak). This may explain why some reports indicate that washing of raspberries was not very effective in preventing infection.

Spring 1998 Outbreak in Ontario:

A large outbreak of cyclosporiasis occurred in Ontario during the spring of 1998.

Several clusters of cyclosporiasis were identified in the Toronto area in early June following:

(1)A call from a private citizen to Toronto Public Health to report that 20 of 35 guests who had attended a party catered at her house on May 9 had developed gastroenteritis and her stool specimens had tested positive for cyclospora; and

(2)A call from New York State CDC to the Ontario Ministry of Health advising of two laboratory-confirmed cases related to a restaurant meal in Toronto on May 15.

An outbreak investigation team was quickly assembled and based at a Toronto Public Health office. The team included:

On-site:

(1)Field Epidemiologist from Laboratory Centre for Disease Control (LCDC), Health Canada;

(2)Epidemic Intelligence Officer and a Food Traceback Officer from U.S. Centers for Disease Control & Prevention (CDC);

(3)Inspector from Canadian Food Inspection Agency (CFIA);

(4)Toronto Public Health staff from five of the six district offices including public health inspectors, Registered Practical Nurses, data analyst, data entry clerks, communications staff, management and support staff and two public health physicians; and

(5)Staff from other involved health departments on an ad hoc basis, eg. York Region, Haliburton-Kawartha-Pine Ridge.

In addition, the scope of the investigation required numerous conference calls between Toronto Public Health, other agencies on-site and the Ontario Ministry of Health Public Health Branch and Central Public Health Laboratory; the Ontario Ministry of Agriculture, Food & Rural Affairs; the other local health departments involved; the CFIA; Health Canada, LCDC and Foodborne-Enteric Diseases Division; Health Canada, Food Directorate; U.S. CDC Division of Parasitic Diseases; and the FDA.

The following components of the outbreak investigation and follow-up are described below:

A.Surveillance

B.Epidemiologic Investigation

C.Laboratory Investigation

D.Traceback Investigation

E.Costs/Budget

F."Post-Mortem" Meeting

1. Surveillance:

In order to help ensure that cases were identified, Toronto Public Health:

(1)issued several media releases starting on June 11, 1998 to alert the public to contact their doctor if they had any symptoms suggestive of cyclosporiasis. There was significant media coverage extending into early July.

(2)Faxed a letter to staff physicians, emergency room staff and infection control staff at Toronto hospitals on June 16, 1998.

(3)Arranged for a notice of alert to be posted on the Ontario Medical Association website and faxed to all family physicians in Toronto.

(4)Established an information line to answer questions and follow-up possible cases.

(5)Posted information on the City of Toronto Website.

The Ontario Ministry of Health informed all health units and private laboratories in Ontario and Health Canada alerted all provincial epidemiologists and laboratory directors.

1. Epidemiologic Investigation:

A detailed and comprehensive epidemiological investigation was conducted to identify the vehicle of the outbreak. For each event associated with a cluster, staff collected a guest list with contact telephone numbers and a detailed description of food items served. Eighty five point eight per cent (85.8%) of individuals (394 of 459) who attended 13 of the events were interviewed using a structured 40 minute questionnaire to gather demographic, clinical and event and non-event food exposure information. One event was not investigated due to concern that many key informants were unable to provide consistent exposure information for the two weeks before onset of illness. Sporadic cases were also interviewed using a structured questionnaire; attempts were made to link sporadic cases to each other and to clusters.

A total of 329 cases were reported in Ontario - 199 related to 14 events/clusters from May 2 to May 23 and 130 sporadic cases that could not be linked to an event/cluster. Fifty-three (53) of the 199 event-related cases and all of the 130 sporadic cases were laboratory-confirmed. Ten of the 14 clusters, involving a total of 149 cases, were in the City of Toronto. These involved events ranging from private parties to large functions including weddings. The other clusters were distributed as follows: 1 in York Region; 1 in Haliburton-Kawartha-Pineridge; and 2 in Simcoe County Health Unit.

No other province or territory reported cases unrelated to travel outside of North America. There were no confirmed outbreaks in the U.S. related to berry consumption.

One hundred and ninety two (192) of the individuals interviewed (or 48.7% of 394) had illness that met the case definition. Fresh raspberries were the only berry and the only food common to all 14 clusters.

For the 13 clusters for which investigations were completed, eating the raspberry-containing item was associated with becoming a case. This association was statistically significant in 5 of the clusters, with relative risks ranging from 2.0 to 8.0. Statistical analysis was difficult for many of the other events where virtually everyone ate the items containing raspberries. The attack rates for persons who ate or probably ate the food items containing raspberries ranged from 25.9% to 100%, with a median of 100%.

Note that the analyses presented above are preliminary. Data will be further analysed using univariate and multivariate statistical methods.

1. Laboratory Investigation:

Stool specimens positive for cyclospora oocyst and received on or after April 15, 1998 if available, were forwarded to the Central Public Health Laboratory for confirmation. Forty-six (46) of the 394 interviewed persons (or 11.7%) from the investigated clusters had specimens that were positive for cyclospora oocysts. CDC demonstrated sporulation of the oocysts in one specimen, i.e. the infectious form.

None of the original food items served at the events were available for testing. However, suspect foods available in some of the places where events occurred were submitted for testing (in particular raspberries and blackberries) at the provincial and FDA labs. Cyclospora could not be confirmed present in samples submitted.

1. Traceback Investigation:

Detailed traceback activities were performed in a collaborative manner among the CDC traceback officer, CFIA and Public Health staff. Tracebacks were conducted to ascertain the distribution and production chain for the food product implicated during the epidemiologic investigation. Data was collected from retailers and distributors (i.e., invoices, inventories, stock rotation, delivery times, estimated turnover rates) and analysed to identify suspect shipments at each level in the distribution chain.

Tracebacks for raspberries served at nine events were well-documented. Tracebacks could not be completed for the other events either because the private consumer did not recall when or where he/she purchased the raspberries or the distributor/retailer had inadequate inventory and distribution records. All raspberries served at these nine events came from two Guatemalan exporters; the CFIA has requested that the Guatemalan authorities complete the traceback to the individual farm level as much as possible.

1. Costs/Budget:

This outbreak was associated with significant costs, both at the individual/family level and the societal level in terms of illness, time lost from work, utilization of the health care system, and governmental work (at the municipal, provincial and federal levels). The true magnitude of this outbreak is not known, and the reported case count likely underestimates the actual number of cases. Preliminary data based on client self-report indicates that of 168 cases involved in 7 clusters: 130 (or 77.4%) consulted their physician; 11 (or 6.6%) visited an emergency room; 2 (or 1.2%) were hospitalized. Health Canada is conducting a cost-analysis study for the outbreak and is in the process of contacting all reported cases to administer a questionnaire.

In terms of costs to Toronto Public Health, 28 frontline and support staff were seconded to work on the outbreak over the period May 18 to July 7, 1998. Total staff time away from regular duties, assignments and workplace was 242 person-days (during regular business hours) plus 760.25 hours overtime. This does not include time worked by management staff (AMOH, communications, lead manager). The Ministry of Health has agreed to cost-share (75% provincial, 25% municipal) the excess costs associated with the outbreak, i.e. overtime and excess administration costs, which total $ 30,404.63.

1. "Post-Mortem" Meeting:

On September 9, 1998 the CFIA hosted a "post-mortem" meeting on the spring 1998 Cyclospora outbreak. Dr. Sheela Basrur and Dr. Barbara Yaffe from Toronto Public Health attended the meeting in Ottawa as well as representatives from the Ontario Ministry of Health Public Health Branch, the Ontario Ministry of Agriculture, Food and Rural Affairs, Health Canada (LCDC, Foodborne & Enteric Diseases Division, and Foods Directorate) and the CFIA. At this meeting there was a review of what happened, the role and mandate of the agencies involved, chronology of events, how decisions were made and areas for improvement, as well as potential plans and policies for the upcoming fall and spring seasons.

The federal Minister of Health remains responsible for establishing policies and standards relating to the safety and nutritional quality of food sold in Canada. The Minister of Health is also responsible for assessing the effectiveness of the CFIA's activities related to food safety.

The CFIA was created April 1, 1997 in an effort to consolidate federally mandated food and fish inspection and animal and plant health activities into a single federal agency reporting to the Minister of Agriculture and Agri-Food. The CFIA's top priorities are (a) health and safety, (b) market access (promoting trade), and (c) consumer fraud (e.g. not declaring an ingredient on list of ingredients). CFIA officials emphasize that health and safety is their top priority.

Although the CFIA is ultimately responsible for decisions regarding the importation of produce, if they have a health and safety concern the Foods Directorate of Health Canada is consulted and may be requested to do a risk assessment.

There is a review process underway between Health Canada and the CFIA to try to address some of the critical issues identified during the outbreak.

Prevention and Control Measures:

A range of prevention and control strategies are discussed below:

(A)Import policies with respect to Guatemalan raspberries, including modification to farm practices and comprehensive risk assessment

(B)Improve detection methodology

(C)Food treatment processes

(D)Labelling product with country of origin

(E)Washing the fruit

(F)Active surveillance

(G)Appropriate infrastructure and emergency response plan to deal with major food borne outbreaks.

(A)Import Policies with respect to Guatemalan raspberries, including modification to farm practices and comprehensive risk assessment ^{2, 15, 22}

It is difficult to be confident of the effectiveness of measures implemented to prevent contamination of raspberries with cyclospora without being certain how contamination occurs. However, with the knowledge of other food contamination experiences and the prevailing hypothesis relevant to cyclospora contamination, a range of measures can be implemented to minimize the risk of contamination. For example, unsanitary conditions on farm fields in some developing nations, including open latrines, and lack of washroom facilities and hand-washing stations, have been proven to be a major hazard for produce contamination.²²

In the case of raspberries exported from Guatemala, the Guatemalan authorities developed a classification system for farms and export plants. Farms and plants are classified as high, medium or low risk for producing, harvesting and packaging cyclospora-contaminated raspberries. The criteria used to classify the farms and plants included an assessment of the source and quality of water used for irrigation and fumigation, building maintenance and employee hygiene, and various administrative record-keeping requirements.

Import policies since spring 1996 are outlined below:

(1)Spring 1996: the Guatemalan spring export season had essentially ended by the time the raspberries were implicated in the investigation of the outbreak¹⁰

(2)Fall 1996: the US and Canada imported Guatemalan raspberries without restriction and no outbreaks of cyclosporiasis were noted;

(3)In anticipation of the spring 1997 export season, the Guatemalan Berry Commission instituted various control measures that focussed on improving the quality of the agricultural water, employee hygiene and sanitation on farms. The industry worked to implement a Hazard Analysis and Critical Control Point (HACCP) system; in such systems, selected points in production at which preventive and control measures can minimize or eliminate hazards are closely monitored. It was agreed that only farms classified as low risk by the Commission on the basis of data gathered by an independent third party could export fresh raspberries to the US in spring 1997.

As noted above, despite these measures another multistate outbreak linked to Guatemalan raspberries occurred in spring 1997. This outbreak stopped after the government of Guatemala and Guatemalan Berry Commission voluntarily suspended exports of fresh raspberries into the US for the period May 29 through August 14.

(4)Fall 1997 experience was the same as the previous fall;

(5)In November 1997 the US FDA advised Guatemalan officials that the US would not allow the importation of fresh raspberries from Guatemala for the period March 15 through August 15, 1998.

(6)At the beginning of the 1998 spring harvest, Guatemalan officials advised the CFIA and Health Canada (HC) that only raspberries produced on farms classified as "low risk" would be exported to Canada during the spring season. Prior to 1998, raspberries were eligible for export to Canada without restriction as to farm origin.

Officials of the CFIA, HC (Food Directorate) and Agriculture and Agri-Food Canada visited Guatemala between March 30 and April 7, 1998, to perform an on-site evaluation of the Guatemalan inspection system and assess the potential microbial risks associated with the production, harvesting and packaging of Guatemalan raspberries. These officials met with Guatemalan technical experts and visited eleven raspberry farms.

Overall, the Canadian group found the Guatemalan system acceptable for low-risk farms, however, some suggestions were made to Guatemalan officials on how to improve their system. Suggestions were as follows: implement an audit system to verify the consistency of inspection delivery; improve the traceback system to identify the source of raspberries in case of food emergency; improve the export control measures to prevent the exportation of raspberries from farms which do not meet Guatemalan export standards.

In addition, it was brought to Canadian officials' attention that the Guatemalan officials were in the process of proposing to the US a "Model Plan of Excellence" (MPE) for the export of raspberries (see below). The Canadian group informed Guatemalan officials that the proposal of shipping berries produced from farms that are classified under the Model Plan of Excellence for the Export of Raspberries, to the United States could be perceived as preferential treatment for the U.S. and Canadian senior management may request the same treatment. A report on the trip's findings and suggestions was submitted to senior Canadian officials in April 1998.

(7)Raspberries from farms identified by Guatemala as "low-risk" were permitted into Canada until June 9, 1998 when Guatemalan raspberries had been implicated in the spring 1998 outbreak and Toronto Public Health staff requested assurances that no further shipments would be permitted into the country. Effective June 9 Canada implemented a policy whereby only those farms certified as meeting the more stringent requirements of the Model Plan of Excellence would be eligible for import into Canada. Guatemala voluntarily ceased shipping raspberries to Canada at this time. As well, the CFIA initiated a Customs Canada Border Lookout (Import Alert) for fresh raspberries from Guatemala.

The occurrence of outbreaks in 1997 and 1998 suggest either that some farms did not fully implement the control measures or that the contamination was associated with a source against which the measures in place were not directed.¹⁰

Model Plan of Excellence:

In the interest of minimizing the risk of exporting cyclospora contaminated raspberries into the U.S., American authorities including the U.S. FDA and the U.S. CDC, assisted the Guatemalan authorities in the revision of the Guatemalan classification system into the Model Plan of Excellence (MPE). The MPE specified additional measures that would minimize the contamination risk including requirements for employee training and the installation of filtration systems to ensure water quality. Generally, the MPE involves the implementation of Good Management Practices in farms and exporter plants and monitoring the system during the picking, classification, packaging and transportation. Farms and exporter plants that meet the criteria of the MPE are classified as low risk. The four components of the MPE are: a) quality assurance, b) training of employees and employers and surveillance of epidemiological risk factors, c) point of origin, and d) tracing (see Appendix 4).

There are some outstanding issues associated with the MPE. Farm and plant classification is carried out by the Integral Program of Agricultural and Environmental Protection (PIPPA), which the U.S. FDA describes as a quasi-governmental organization created by a Guatemalan ministerial agreement in 1991.¹⁵ In addition, according to the CFIA, the Guatemalan authorities have indicated that the filters required for the water filtering system are maintained according to manufacturer's instructions, which have not yet been made available by Guatemalan authorities.² The U.S. FDA has indicated that a filter protocol which addresses additional parameters such as the replacement of filters and the testing of water, has been provided to the U.S. FDA for review and comment.¹⁵ The U.S. FDA will be providing comments on this protocol as part of its continuing review of the MPE. As well, the U.S. FDA will be visiting Guatemala in November or December 1998 to train PIPPA personnel in inspection techniques, focussing on raspberries as well as other commodities.

(8)Fall 1998: the FDA policy is to accept Guatemalan raspberries from both low and medium-risk farms.

The CFIA, in collaboration with Health Canada, has decided that the importation of Guatemalan raspberries from the fall harvest will not be allowed until a team of representatives from the relevant federal agencies make a visit to audit the Guatemalan farms under stress conditions (full harvest) (See Appendix 5). The purpose of the visit is two-fold: a) address outstanding questions; and b) to observe how well the MPE has been implemented. Also, the CFIA wants to ensure that the Guatemalan authorities are adequately enforcing the prohibition of mixing raspberries that originate from various farms for export. This visit is planned for early November 1998.

(9)For spring 1999: no decisions have been made yet regarding the importation of Guatemalan raspberries. The FDA is planning to conduct an audit this fall re MPE farms for the spring. The CFIA has indicated an interest in partnering with the FDA to negotiate a spring 1999 policy and the Foods Directorate plans to conduct a risk assessment.

Toronto Public Health has been an active participant in discussions on this issue since spring 1998 and will continue to do so. The Board of Health does not have jurisdiction with respect to importation of foreign produce. In terms of the legal powers of the Medical Officer of Health we are limited to acting when we have reasonable and probable grounds that a health risk exists. Toronto Public Health played a major role in decisions made during the spring 1998 outbreak. However, that is after the fact; the focus must be on prevention. Staff participated in discussions at the "post-mortem" meeting hosted by the CFIA on September 9, 1998 and indicated an active interest in continuing to be involved in discussions regarding policy for the spring 1999. As well, we will continue to monitor the situation and keep the public and health care providers informed as appropriate.

(B)Improve Detection Methodology

The Ontario Public Health Laboratory and CFIA laboratory both use microscopy, which is virtually unable to detect cyclospora on raspberries. Research using PCR (Polymerase Chain Reaction) with RFLP (Restricted fragment length polymorphism) to detect cyclospora oocysts is being conducted in selected labs in the US. The PCR technique is capable of detecting as few as five oocysts under ideal conditions, but testing foods is not ideal. Enzymes naturally present in raspberries inhibit the PCR reaction significantly. There are only small numbers of oocysts present and they are difficult to wash off raspberries.

The Health Protection Branch is also conducting research on improving detection methodology for cyclospora.

(C)Food Treatment Processes

Food treatment processes are used to eliminate the pathogen from the food product but do not attempt to minimize contamination. Examples of treatment processes include pasteurization and irradiation. Food irradiation involves the exposure of food to ionizing radiation at doses that range from 0.5 to 10 kGy. Different doses are used to achieve different outcomes. For example, low doses can be used to inhibit sprouting of vegetables, to delay ripening of fruit and vegetables and for insect disinfestation of species and wheat. Higher doses are used to reduce the food's microbial load and to kill parasites in meat. At this time, it is not clear whether irradiation, at doses that would retain the integrity and aesthetic quality of the fruit, would eliminate cyclospora from raspberries. The effect of gamma irradiation on cyclospora oocysts is being investigated.⁹ In addition to irradiation, other treatment processes, claiming to be effective in eliminating food borne pathogens such as cyclospora, are emerging.

(D)Labelling Produce with Country-of-Origin

Although labelling fresh produce with its country-of-origin does not address the issue of contamination, it can contribute to a more informed choice for the consumer. Responsibility for country-of-origin rules is divided between the federal and provincial governments.

The federal government, through the CFIA, regulates pre-packaged, imported fresh fruits and vegetables. This authority is provided under the Canadian Agricultural Products Act (CAPA). Pre-packaged means the product comes into the country in a container used for selling to consumers (e.g. a 5 lb. bag, a small plastic container for berries), and there is no repackaging for consumers. Pre-packaged goods must have on the container, the country of origin, grade and name and address of the supplier. The size of the lettering for country of origin is dictated by the size of the bag/container according to rules spelled out in the federal Consumer Packaging and Labelling Act.

There are no requirements for domestic pre-packaged fruits and vegetables to have the phrase "product of Canada" on the label, although there is a requirement for a federal grade standard. It appears that the rules assume that consumers can determine whether a product is domestic from the absence of a country of origin label saying otherwise. Since imported products often have Canadian grade standards on them, the presence of a grade does not necessarily indicate the product's origin.

The CFIA enforces the country of origin rules at the importer/wholesale level. Although there is some regular inspection, most of the enforcement work is done on a complaints basis due to resource limitations.

Provincial rules apply to the marketing of fresh, whole, raw product in bulk at any place of trade where food is sold to consumers directly, including retail stores and farmers' markets. The province has no jurisdiction or rules when produce is cooked, or sold at wholesale. The governing legislation is the Ontario Farm Products Grade and Sales Act, Reg. 378. It requires that there be signage at the point of sale providing the country of origin, price/volume, and grade. The sign must say "Product of [country or province]". The law only says that the sign must be there and that the markings cannot be fraudulent or misrepresentative. The federal Consumer Packaging and Labelling rules determine the size of the lettering (no less than one-quarter of an inch in height). The size of the sign is not regulated by provincial statute, so the lettering must only be proportional to the size of the sign.

Enforcement is a problem since staff in the responsible Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA) division have been severely cut back. They now only respond to and follow-up on complaints at the retail or corporate level. Other complaints are referred to federal or industry officials. There is no proactive monitoring. OMAFRA is actively promoting compliance through educational and promotional programs.

There is no requirement to provide information on the origin of fruits and vegetables in restaurants, food service operations, or at the wholesale level, unless the food is prepackaged and imported and destined for the consumer. Country of origin labels are also not required for processed fruits and vegetables. Some labels of processed fruits and vegetables carry the statement "made in Canada", but according to the federal Guide to Food Labelling and Advertising, the notice "made in Canada or product of Canada implies that the food was manufactured in this country. However, these statements do not necessarily mean that all of the ingredients used are domestic". Consequently "made in Canada" statements do not serve well as proxies for country of origin labels.

There is considerable room for consumer confusion in these rules. Since enforcement is a problem, products may not be properly labelled or the proper signage may not be in place. The products may be labelled, but the lettering may not be clear or legible. Information on country of origin is not uniformly applied to all fruits and vegetables, so consumers may consume these foods in instances for which no labelling or signage is required. This would include, for example, eating fresh fruit sold in a cafeteria or jam manufactured in Canada with imported ingredients.

(E)Washing the Fruit⁹

Although it is always prudent to wash fresh produce well prior to consumption, fresh raspberries may still remain contaminated because they are too fragile and replete with crevices to be washed thoroughly. The high attack rates experienced in most events, sometimes after consuming only a few raspberries, suggest that the infectious dose of oocysts is low and/or the number of oocysts per berry is high.

(F)Active Surveillance

Cyclosporiasis is not designated a reportable disease in Ontario or Canada at the national level. Thus the number of cases reported to public health authorities is likely a significant underestimate of the true numbers. Although private laboratories which do most of the testing for parasites in the Greater Toronto Area do routinely test for cyclospora and report to local health units, many people do not seek medical attention for diarrhea, physicians may not think of cyclospora and/or order the appropriate tests and not all laboratories are equipped to do the tests. During outbreaks reporting increases as public and health care provider awareness rises (due to media coverage and special communications to physicians, labs etc.).

Newfoundland is the only province which has made cyclospora reportable (although they have not had any laboratory-confirmed cases). In the US five states and one municipality have made cyclosporiasis reportable: Florida, South Carolina, Connecticut, Maryland, Massachusetts and New York City. As well, the American Council of States and Territorial Epidemiology passed a resolution in June 1998 to make cyclosporiasis nationally reportable and to encourage each state to establish a surveillance program aimed at increasing our knowledge of cyclospora epidemiology.

The Canadian Advisory Committee on Epidemiology will be considering making cyclosporiasis nationally reportable at their meeting in October 1998.⁷

Cyclosporiasis should be made reportable to public health units in Ontario well in advance of spring 1999 to help ensure that public health is apprised of all suspect/confirmed cases as quickly as possible. This matter must be raised with the Disease Control Service of the Ontario Public Health Branch.

In addition, an active surveillance system for cyclospora and other important foodborne diseases should be considered at the federal level to better estimate the frequency and severity of these diseases, describe their epidemiology and help develop prevention and control measures. For example, the U.S. Centers for Disease Control & Prevention established FoodNet in 1995 in collaboration with the US Food & Drug Administration, U.S. Department of Agriculture and seven sites. In FoodNet Public Health officials:

(1)survey laboratories regarding testing practices and specific cases;

(2)survey physicians regarding stool culturing practices; and

(3)survey randomly selected residents in a catchment area regarding recent diarrheal illness.

(G)Appropriate Infrastructure and Emergency Response Plan to deal with Major Foodborne Outbreaks

This outbreak is a reminder that our supply of fresh produce has become increasingly international and underscores the need to identify and investigate food borne outbreaks promptly, to consider that a local cluster of cases could be part of a widespread outbreak, and to pursue investigations to the source of the implicated vehicle.⁹ There needs to be a more coordinated and planned approach involving relevant agencies at the international, national, provincial and municipal levels to monitor the epidemiology, share information and conduct investigations of major outbreaks in an effective, efficient manner. This must include a primary focus on protecting the public health, clarification of roles and responsibilities, staff training (e.g. to do comprehensive food traceback investigation) and communication plan etc. The Health Protection Branch and the CFIA are currently working on an emergency response protocol.⁷

Conclusions:

Foodborne disease is emerging as a critical public health issue in North America. In Ontario, for the third year in a row people have experienced a potentially preventable outbreak of cyclosporiasis. In the outbreaks of spring 1996 and spring 1998 fresh Guatemalan raspberries have been implicated through comprehensive epidemiological and food traceback investigations. Hundreds of people have become ill, missed work and utilized the health care system. We must learn from this experience and ensure that it is not repeated. Specific recommendations are made with respect to the prevention and control of cyclosporiasis as well as other foodborne pathogens.

Contact Name:

Dr. Barbara Yaffe,

Director of Communicable Disease Control & Associate MOH,

Toronto Public Health

Tel:392-7405

Fax:392-0713

Email:byaffe@city.toronto.on.ca

Dr. Sheela V. Basrur

Medical Officer of Health

APPENDIX 1

FACTORS CONTRIBUTING TO THE EMERGENCE OF INFECTIOUS DISEASE

(CDC, 1994)

Factors influencing the emergence and re-emergence of "new" pathogens and "old" pathogens are numerous and reflect an interplay of biological and sociological forces.¹⁸ An emerging ecological view surmises that as we see increased centralization and globalization in the food system, there will be a concomitant increase in homogeneous ecological niches for infectious agents.²⁴ Contamination, associated with agricultural practices, is occurring earlier in the production process, and then the longer distribution chains create more opportunities for both disease development and contamination with additional pathogens. Because of the wide dispersal of foods from centralized facilities, there is a greater likelihood that a low-level contamination can produce diffuse and widespread outbreaks.¹⁷

These kinds of infections demand new control strategies that start right at the farm level. But increasing fiscal pressures and diminishing public resources devoted to inspection appear to make implementation of this approach unlikely in the short term. Governments are moving toward an inspection system based on the scientific assessment of risk, and a risk-based allocation of resources.⁸

A variety of initiatives are being developed in this area:

The US Senate Subcommittee on Investigations has been conducting hearings on the safety of imported food. Cyclospora has been used as an example at those hearings.

The Institute of Medicine National Research Council has just published a book entitled "Ensuring Safe Food - From Production to Consumption" which makes recommendations on how to improve the safety of the food supply in the US.¹² As our food supply grows more complex, so does the challenge of protecting it from contamination. A dangerous mix of factors including the emergence of new strains of food borne bacteria, new food processing and production techniques, consumer demand for ready-to-eat meals, and a rising number of people who are more susceptible to food borne illnesses have placed new stresses on our efforts to keep the food supply safe.

According to the CFIA, there are three domestic initiatives under development that address the broader issues of contamination with food borne pathogens:²

(a)On-Farm Food Safety Initiative is a voluntary initiative that assists farmers in developing a food safety program. The CFIA assists in tailoring the program to the specific food-safety issues related to the type of produce grown on individual farms.

(b)The CODEX Alimentarius Commission, under the Food and Agriculture Organization of the United Nations, has requested Canada to prepare a discussion paper on the development of a Code of Practice for the production, harvesting and packaging of fresh fruit and vegetables.

(c)A Domestic Code of Practice is under development for the production , harvesting and packaging of domestically grown fruit and vegetables. This Code of Practice will be used in the On-Farm Food Safety Initiative.

The Ontario Government has launched an interagency initiative between health units and provincial ministries to develop an Ontario Food Safety Strategy (OFSS). This will include work to enhance interagency inspection efforts. There are no municipal representatives on the OFSS provincial steering committee to our knowledge.

Given that these new pathogens present increased and still often unacknowledged risks, whether the government's approach will be able to address the volume of problems, both current and potential, is unclear.

APPENDIX 2

CYCLOSPORA AND CYCLOSPORIASI

INFORMATION FOR HEALTH CARE PROVIDERS

What is Cyclospora?

Cyclospora cayetanenis is a unicellular parasite previously known as cyanobacterium-like or coccidia-like body (CLB). The first known human cases of illness caused by cyclospora infection (i.e., cyclosporiasis) were reported in the medical literature in 1979. Cases have been reported with increased frequency from various countries since the mid 1980s, in part because of the availability of better techniques for detecting the parasite in stool specimens.

How is cyclospora transmitted?

Infected persons excrete the oocyst stage of cyclospora in their feces. When excreted, oocysts are not infectious and may require from days to weeks to become infectious (i.e., to sporulate). Therefore, transmission of cyclospora directly from an infected person to someone else is unlikely. However, indirect transmission can occur if an infected person contaminates the environment and oocysts have sufficient time, under appropriate conditions, to become infectious. For example, cyclospora may be transmitted by ingestion of water or food contaminated with oocysts. Outbreaks linked to contaminated water, as well as outbreaks linked to various types of fresh produce, have been reported in recent years. How common the various modes of transmission and sources of infection are is not yet known, nor is it known whether animals can be infected and serve as sources of infection for humans.

Who is at risk for infection?

Persons of all ages are at risk for infection. Persons living or travelling in developing countries may be at increased risk; but infection can be acquired worldwide, including in the United States. In some countries of the world, infection appears to be seasonal.

What are the symptoms of infection?

The incubation period between acquisition of infection and onset of symptoms averages 1 week. Cyclospora infects the small intestine and typically causes watery diarrhea, with frequent, sometimes explosive stools. Other symptoms can include loss of appetite, substantial loss of weight, bloating, increased flatus, stomach cramps, nausea, vomiting, muscle aches, low-grade fever and fatigue. If untreated, illness may last for a few days to a month or longer, and may follow a remitting-relapsing course. Some infected persons are asymptomatic.

How is infection diagnosed?

Identification of this parasite in stool requires special laboratory tests that are not routinely done . A single negative stool specimen does not rule out the diagnosis; three or more specimens may be required. Stool specimens should also be checked for other microbes that can cause a similar illness.

How is infection treated?

Trimethoprim/sulfamethoxazole (TMP/SMX), or Bactrim*, Septra*, or Cotrim*, has been shown in a placebo-controlled trial to be effective treatment for cyclospora infection.

Patients with AIDS may need higher doses and long-term maintenance treatment.

No alternative antibiotic regimen has been identified yet for patients who do not respond to or are intolerant of TMP/SMX. Approaches to consider for treatment of such patients include observation and symptomatic treatment, use of an antibiotic whose effectiveness against cyclospora is unknown or is based on limited data, or desensitization to TMP/SMX. The latter approach should be considered only for selected patients who require treatment, have been evaluated by an allergist, and do not have a life-threatening allergy.

How is infection prevented?

Based on currently available information, avoiding food or water that maybe contaminated with stool is the best way to prevent infection. Reinfection can occur.

Source: Excerpted from information provided by Public Health Branch, Ontario Ministry of Health, June 1998.

APPENDIX 4

MODEL PLAN OF EXCELLENCE

(a)Quality Assurance

Quality assurance is defined in the MPE as implementation of the following measures at each farm and/or exporter:

Good agricultural practices - an inspector controls the use of pesticides, fertilizers, the drip irrigation system, the potable water used for spraying and hand washing, and crop management.

Good manufacturing practices - an inspector verifies proper maintenance of the infrastructure conditions, proper hygiene practices of harvesting personnel and compliance with the pest control program and the clean-up and sanitation plan for the packaging facilities and equipment.

Water quality - an inspector ensures that the microbial quality of the water is monitored. Initially, one water sample will be taken 15 days prior to the start of the harvesting season. During harvesting, two samples per month will be analyzed. All the farms are required to install a microbial filter with a mesh no bigger than 0.5 microns to filter the water used for the clean-up plan and for the application of pesticides and herbicides.

(b)Training of Employees and Employers and Surveillance of Epidemiological Risk Factors

In order to be considered a low risk farm or exporter plant, implementation of a training program on good hygienic practices and a surveillance program to assess risk factors on raspberry producing farms is required.

(c)Point of Origin

Inspections at various points in the production, packaging and transportation are carried out to guarantee the origin of the raspberries. The CFIA observed that there was no consistent labeling system that identified the grower farm. Therefore, CFIA suggested a universal numbering system that assigns an identification number to each grower farm. The farm number would be placed on each clamshell container prior to shipping.

(d)Traceback

The exporter firms will keep a weekly record of the final destination of the fruit once the product has arrived at its final location.

REFERENCES

1. Buck, P., Huang, S. An Outbreak of Cyclosporiasis in Ontario, 1998. Report by Field Epidemiology Training Program, LCDC, Health Canada in collaboration with Centers for Disease Control & Prevention, Atlanta, USA (Unpublished).
2. Cardinal, R., Chief, Fresh Fruits & Vegetables, Canadian Food Inspection Agency. Personal Communications. June-Sept. 1998.
3. CDC. Update: outbreaks of cyclosporiasis - United States and Canada, 1997. MMWR 1997; 46:521-3.
4. CDC. Outbreak of cyclosporiasis - northern Virginia-Washington, D.C. - Baltimore, Maryland, metropolitan area, 1997. MMWR 1997; 46:689-91.
5. Centers for Disease Control & Prevention, Website, Sept. 1998. FoodNet, CDC/USDA/FDA Foodborne Diseases Active Surveillance Network.
6. Centre for Disease Control. 1994. Addressing emerging infectious disease threats: a Prevention Strategy for the United States. Executive Summary. MMWR 43:(RR5):1-18.
7. Ellis, A., Foodborne-Enteric Diseases Division, Health Canada, Personal Communications. June-September 1998.
8. Government of Canada, Canadian Food Inspection Agency (CFIA). 1997. Charting the Future: Exploring Directions for the Agency's Corporate Business Plan. Government of Canada, Ottawa, May 1997.
9. Herwaldt, B.L., Ackers, M.L. and Cyclospora Working Group. An Outbreak in 1996 of Cyclosporiasis Associated with Imported Raspberries. NEJM May 29, 1997, 336:1548-1556.
10. Herwaldt, B.L., Division of Parasitic Diseases, United States Centers for Disease Control & Prevention, Atlanta. Personal Communications, June-August 1998.
11. Huang P. et al. The first reported outbreak of diarrheal illness associated with Cyclospora in the United States. Ann Intern Med 1995; 123:409-14.
12. Institute of Medicine, National Research Council, Washington DC, 1998. Ensuring Safe Food: From Production to Consumption.
13. Osterholm, M.T. Cyclosporiasis and Raspberries - Lessons for the Future (Editorial). NEJM May 29, 1997, 336:1597-1598.
14. Pichette, S. Traceback Activities for an outbreak of cyclosporiasis in Ontario, 1998. Report by Division of Parasitic Diseases, Centers for Disease Control & Prevention, Atlanta, USA (Unpublished).
15. Reynolds, C.V. Director, Office of Field Programs, United States Food & Drug Administration, Personal Communications, August 1998.
16. Smith, S. U.S. Senate Subcommittee on Food Safety. Personal Communication. August 1998.
17. Tauxe, R.V. 1997. Emerging Food borne Diseases: An Evolving Public Health Challenge. Emerging Infectious Diseases, Oct.-Dec. 1997, 3(4):425-434.
18. Toronto Board of Health, 1996. Emerging and Re-emerging Infectious Diseases. City Clerk, Toronto. May 27, 1996.
19. Toronto Board of Health, 1997. Is Food the Next Public Health Challenge? City Clerk, Toronto, August 1997.
20. United States Senate Permanent Subcommittee on Investigation, Committee on Government Affairs. April 1998. Food Safety - Federal Efforts to Ensure the Safety of Imported Foods are Inconsistent and Unreliable. U.S. General Accounting Office, Washington D.C.
21. United States Food & Drug Administration. July 23, 1997. Public Meeting on Cyclospora.
22. United States Senate Permanent Subcommittee on Investigations, Committee on Governmental Affairs. Press release May 7, 1998 including Opening Statement by Chairman and Witness Statements May 14, 1998). The Safety of Food Imports.
23. United States Senate Permanent Subcommittee on Investigations, Committee on Governmental Affairs. Press release June 29, 1998. The safety of Food Imports: From the Farm to the Table - A Case Study of Tainted Imported Fruit.
24. Waltner Toews, D. 1992. Food, Sex and Salmonella. NC Press, Toronto.