The Canadian Food Inspection Agency (CFIA) implemented a 2-year surveillance of wild fish in Canada for the presence of viral hemorrhagic septicaemia virus (VHS virus) in the spring of 2007. The bilateral surveillance plan was developed by the Aquatic Animal Health Division (AAHD) of CFIA, Fisheries and Oceans Canada (DFO), Animal and Plant Health Inspection Service (APHIS) of the US Department of Agriculture (USDA), U.S. Fish and Wildlife Service (USFWS), and the Great Lakes Fish Health Committee.
One thousand and fifty-five (1,055) wild fish, originating from medium to high risk watersheds for VHS virus infection, were tested for VHS virus. These fish were sampled from 3 different watersheds in Ontario (Big, French and Scugog) and 1 in Québec (St. Lawrence River - 3 freshwater sites: Lac St. Louis, Lac St. François and near Bécancour). All fish were negative for VHS virus.
The freshwater portion of the St. Lawrence River, east of Moose Saunders Dam is currently considered a high risk watershed for infection with VHS virus. Since it is connected directly to Lake Ontario, a positive watershed, it is recommended that the status of this watershed be checked annually. The risk of infection for VHS virus in the Big (high), French (high) and Scugog (medium) watersheds is unchanged as well, and it is recommended that fish in these watersheds be sampled again in 2008.
While not part of this sampling effort, DFO did confirm one (1) VHS virus-infected fish in the lower Thames River watershed resulting from the Ontario Ministry of Natural Resources (OMNR) 2007 spring survey, funded by the Canada-Ontario Agreement Respecting the Great Lakes Basin Ecosystem. It is recommended that the Lower Thames watershed be sampled in the fall of 2007.
Isolation of VHS virus was also confirmed from a fish die-off in Hamilton Harbour in May 2007. Lake Ontario is a known positive watershed for VHS virus.
Viral hemorrhagic septicemia virus (VHS virus) is a rhabdovirus that infects a wide range of marine, brackish and freshwater fish species, including anadromous species, such as Chinook and Coho salmon, and catadromous species, such as American eels and Striped bass. To date, the virus has been found in over 65 different fish species. Four major genogroups of VHS virus have been identified (Einer-Jensen et al., 2004; Snow et al., 2004). Genogroup I consists mainly of freshwater strains of VHS virus isolated from fish in Europe. Genogroup I strains have also been isolated from marine fish around Europe and Rainbow trout raised in brackish water around Finland. Genogroups II and III are endemic in wild marine fish found around Europe. However, a genogroup III strain has also been isolated from Greenland flounder caught at the Flemish Cap, about 600 km east of Newfoundland. Genogroup IV is considered endemic in certain populations of wild marine fish along the Pacific coast of North America and in Japan (subgroup IVa). Another subgroup of genogroup IV was isolated from mummichogs, sticklebacks, Striped bass and sea-run Brown trout on the Atlantic coast of Canada (Gagné et al., 2007). The subgroup has not yet been formerly named, but is currently referred to as IVc.
Recently, in 2003, 2005, 2006 and 2007, another subgroup of genogroup IV, distinct from other sequenced North American (east and west coast) VHS virus IV isolates, has emerged in free-ranging freshwater fish species of the Great Lakes region (Elsayed et al., 2006). This subgroup has been named IVb. Multiple large die-offs in the Great Lakes region involving at least 14 different species have been attributed to VHS virus IVb since the spring of 2005. The first large die-off was recorded in the Bay of Quinte on the Canadian side of Lake Ontario in Freshwater drum. To date, subgroup IVb has not been detected in aquaculture facilities in Canada.
In response to these die-offs and in order to protect the catfish aquaculture industry, the United States Department of Agriculture issued a Federal Order on October 24, 2006 restricting movement into and throughout the U.S.A. of 37 species of live fish from Ontario, Québec and 8 States surrounding the Great Lakes. The Order has been amended twice since then; one amendment was to allow importation of live salmonids from Canada with the condition of negative test results (USFWS Blue Book protocols or equivalent; in Canada, testing is done under the Fish Health Protection Regulations), and the other amendment was to allow importation of live fish associated with fishing derby activities (http://www.aphis.usda.gov/newsroom/hot_issues/vhs/vhs.shtml; accessed August 31, 2007). Several U.S States have also imposed additional regulations regarding importation of live fish and movement of bait fish species.
The province of Ontario has also placed some restrictions on the movement of live bait fish, and on wild egg collections and subsequent stocking. In addition, OMNR now requires an impact assessment on any new proposals to move fish (http://www.mnr.gov.on.ca/MNR/fishing/VHScontrol.html; accessed August 31, 2007).
Canada exports fish and seafood in excess of $4.3 billion CDN every year. The bulk of the exports go to the U.S.A.. Exact live fish exports (magnitude and dollar value) are unknown. In 2005, approximately 1 million dozen bait fish were exported from Ontario into the U.S.A.. That has now ceased. Other live fish exports from Canada include catfish and other species for the human food market.
Since the Great Lakes are a shared water resource, and because VHS virus is a World Organization for Animal Health (OIE)-listed disease that can impact Canada's international trade opportunities, the recent emergence of a new strain of VHS virus in freshwater fish in the Great Lakes region prompted the Canadian Food Inspection Agency (CFIA), U.S. Department of Agriculture (USDA) and U.S. Fish and Wildlife Service (USFWS) to undertake development of a bilateral VHS virus surveillance plan. The bilateral surveillance plan is consistent with OIE guidelines on surveillance for disease freedom as outlined in the OIE Manual of Diagnostic Tests for Aquatic Animals, (http://www.oie.int/eng/normes/fmanual/A_summry.htm?e1d11).
Sampling of susceptible freshwater fish species will be conducted primarily in the spring and fall when water temperatures favour the detection of VHS virus. This report outlines the implementation of surveillance for VHS virus in wild fish in the Great Lakes - St. Lawrence Basin. The effort was undertaken in Ontario and Québec fresh waters by the CFIA in partnership with provincial authorities in the spring of 2007.
This initial targeted surveillance effort will occur over a 2-year period (spring 2007 to fall 2008). Ongoing surveillance design (beginning in spring 2009, and under the auspices of the National Surveillance Program) will be based upon the evaluation of this initial surveillance period, resultant disease status of watersheds in Canada, and any planned disease control measures.
The objectives of the bilateral surveillance effort are to:
Due to resource constraints, for the spring 2007 effort in Canada, surveillance was conducted in wild freshwater fish in medium to high risk watersheds in Ontario and Québec. Fish were also sampled in Lake Erie to serve as a validation population for a rapid screening test for VHS virus. The surveillance was based on the bilateral, CFIA and USDA document: "Surveillance Proposal for Viral Hemorrhagic Septicemia Virus In Freshwater Fish in Canada and the United States, Version 1.0" (available upon request from the Aquatic Animal Health Division, CFIA).
The spring 2007 surveillance plan consisted of 2 components:
CFIA-Aquatic Animal Health Division (AAHD), CFIA-Operations, DFO-NAAHLS (National Aquatic Animal Health Laboratory System), Ontario Ministry of Natural Resources (OMNR), Agriculture, Pêcheries et Alimentation Québec (MAPAQ) and the University of Guelph met on February 28 and March 1, 2007 to determine the surveillance methods for spring 2007.
Subsequent collaborative documents arising from this meeting included:
Surveillance was directed towards selection of tertiary watersheds with the highest risk for VHS virus infection: watersheds that had a direct connection to known infected watersheds (Lake Ontario, Lake Erie, Lake St. Clair, and Lake Huron) and watersheds that had received large numbers of bait fish harvested from infected waters prior to regulatory restrictions. A risk of 'high' was given to tertiary watersheds that had a direct connection to positive watersheds. A risk of 'medium' indicated that the watershed had no direct connection to a positive watershed but had, in the past, received large volumes of live bait fish from positive waters. A risk of 'low' was applied to watersheds where there was no direct connection to positive waters and the watershed had not knowingly received large volumes of live bait fish. Secondary considerations for watershed selection included anticipated presence of provincial sampling crews, and distance from DFO laboratories (samples had to reach laboratories in a defined time period).
At least 170 fish (from 1 or more susceptible species) were sampled from each selected watershed. The sample size was based on detecting the virus at a prevalence of 2% within the fish population, with a test sensitivity of 85% and test specificity of 100% (viral isolation and identification by RT-PCR. Fish were collected repeatedly until the desired sample size was reached.
Sampling was conducted by OMNR or Ressources naturelles et Faune Québec (MRNFQ). In addition, the provinces of Ontario and Québec provided resources to enhance reporting and investigation of wild fish kills in their respective provinces.
An initial qualitative evaluation (positive, high, medium, or low) of the probability of VHS virus infection in each tertiary watershed of the Great Lakes-St. Lawrence Basin in Ontario and Québec is provided in Table 1. This evaluation was based on the following risk factors: direct connection to an infected watershed and history of large volumes of live bait fish introductions. A risk of 'high' denotes that the tertiary watershed has a direct connection to positive watersheds. A risk of 'medium' indicates that the watershed has no direct connection to a positive watershed but has received large volumes of live bait fish from positive waters in the past. A risk of 'low' indicates that there is no direct connection to positive waters and the watershed has not knowingly received large volumes of live bait fish.
The initial list of 21 medium to high risk tertiary watersheds in Ontario, south of Parry Sound, and in Québec was pared down to 5 because of limitations related to availability of sampling crews and sample processing resources at DFO-NAAHLS. In addition, constraints were also imposed by rising water temperatures. Sampling began in the beginning of May and was discontinued towards the end of May due to rising water temperatures.
All fish tested were from healthy populations. Results can be found in Table 2.
The Ontario Ministry of Natural Resources (OMNR) received funding from the Canada-Ontario Agreement Respecting the Great Lakes Basin Ecosystem to conduct their own surveillance for VHS virus in inland waters. The OMNR-initiated surveillance was not part of the CFIA bilateral surveillance program. The DFO-VHSV National Reference Laboratory confirmed a positive result from a Largemouth bass (Micropterus salmoides) in the lower Thames River watershed. It is recommended that this watershed be sampled by CFIA in the fall of 2007.
As part of the 2007 surveillance for VHS virus, the Ontario and Québec governments encouraged reporting of wild fish kills in their respective province and conducted disease investigations of fish kills. One (1) VHS virus-related Freshwater drum (Aplodinotus grunniens) die-off was reported in Ontario; the die-off occurred in Hamilton Harbour, Lake Ontario. Viral isolation and preliminary RT-PCR identification was conducted by the University of Guelph and confirmatory testing was conducted by the VHSV National Reference Laboratory at DFO-Pacific Biological Station, Nanaimo, BC. Lake Ontario is a known VHS virus-infected watershed and the isolation occurred in a previously identified susceptible species of fish.
The following are definitions for classifying the sampled population of fish and the sampled watershed as positive for VHS virus, according to the bilateral national surveillance plan for Canada and the United States.
According to these definitions, VHS virus-positive tertiary watersheds in Canada include Lake Huron, St. Clair River, Lake St. Clair, Detroit River, Lake Erie, Niagara River, Lake Ontario and the St. Lawrence River west of the Moose Saunders Dam at Cornwall, ON. Fish were not sampled in these areas, except one population of White bass (Morone chrysops) in Lake Erie used to validate a rapid RT-PCR method for detection of VHS virus in future surveillance efforts. Results from these fish are not included in this surveillance report as the validation is on-going.
Negative test results indicate that we are 95% certain that less than 2% of the sampled populations of wild fish in this study would be infected with VHS virus if the virus was present. This finding indicates that we are reasonably certain that the sampled populations of fish were free of VHS virus. However, these findings cannot be used to make claims of freedom at the tertiary watershed level; the sampled watersheds cannot be said to be free of VHS virus.
For the next sampling period more information will be collected on important risk factors for VHS virus infection of a watershed to help with interpretation of the test-based surveillance results. CFIA and USDA are currently conducting an expert-derived evaluation of risk factors for VHS virus infection at the watershed level; the results of the evaluation along with surveillance results in each watershed will be used to calculate an estimate of the probability of infection. Thereafter, results from each surveillance period will be used to update the probability of infection for each tertiary watershed. These probabilities will be reported in future reports. For example, it is expected that the probability of VHS virus infection for the St. Lawrence River east of the Moose Saunders Dam or east of the Beauharnois Dam will decrease because these dams serve as barriers to fish movement.
The probability of VHS virus infection for a watershed will determine the amount of sampling that will be required in the future in order to declare a watershed free of the virus. Consultation between AAHD-CFIA and watershed stakeholders will determine if this objective will meet the needs of fish disease control and fish trade requirements.
Einer-Jensen K, Ahrens P, Forsberg R, Lorenzen N. 2004. Evolution of the fish rhabdovirus viral haemorrhagic septicaemia virus. Journal of General Virology 85: 1167-1179.
Elsayed E, Faisal M, Thomas M, Whelan G, Batts W, Winton J (2006) Isolation of viral haemorrhagic septicaemia virus from muskellunge, Esox masquinongy (Mitchill), in Lake St Clair, Michigan, USA reveals a new sublineage of the North American genotype. Journal of Fish Diseases 29:611-619.
Gagné N, MacKinnon A-M, Boston L, Souter B, Cook-Versloot M, Griffiths S, Olivier G. 2007. Isolation of viral hemorrhagic septicemia virus from mummichog, stickleback, striped bass and brown trout in eastern Canada. Journal of Fish Diseases 30: 213-223.
Snow M, Bain N, Black J, Taupin V, Cunningham CO, King JA, Skall HF, Raynard RS. 2004. Genetic population structure of marine viral haemorrhagic septicaemia virus (VHSV). Diseases of Aquatic Organisms 61: 11-21.
1 One or more fish culture facilities under a common biosecurity management system containing an aquatic animal population with a distinct health status with respect to a specific disease or diseases for which required surveillance and control measures are applied and basic biosecurity conditions are met for the purpose of international trade. Such compartments must be clearly documented by the Competent Authority. In Canada, the OIE-recognized Competent Authority is the CFIA.
For the purposes of this surveillance plan, a compartment is a fish culture facility with the following characteristics:
2 Active observational surveillance is the process of actively and systematically looking for diseased animals by a knowledgeable individual, on a frequent, pre-planned, and ongoing basis, where a predefined plan of action is implemented when affected animals are discovered. For more details, see "Surveillance Proposal for Viral Hemorrhagic Septicemia Virus In Freshwater Fish in Canada and the United States, Version 1.0" (available upon request from the Aquatic Animal Health Division, CFIA).
Table 1: Qualitative evaluation for risk of VHS virus infection of tertiary watersheds in the Great Lakes Basin, including the St. Lawrence River (up to its tidal limit). These watersheds are located in Ontario and Québec. A risk of 'high' denotes that the tertiary watershed has a direct connection to positive watersheds. A risk of 'medium' indicates that the watershed has no direct connection to a positive watershed but has received large volumes of live bait fish from positive waters in the past. A risk of 'low' indicates that there is no direct connection to positive waters and the watershed has not knowingly received large volumes of live bait fish. Watershed codes and names were derived from the National Scale Frameworks Hydrology - Drainage Areas, Canada database [http://geogratis.cgdi.gc.ca/geogratis/en/option/select.do?id=27730].
Secondary Watershed Code Number | Tertiary Watershed Code Number | Name | Risk of VHSV Infection |
---|---|---|---|
154 | 821 | Lower St. Lawrence - du Loup | Low |
154 | 911 | Etchemin | Low |
154 | 944 | Chaudière | Low |
154 | 967 | Bécancour | Low |
154 | 946 | Lower St. Lawrence - du Chêne | Low |
154 | 900 | Batiscan | Low |
154 | 912 | Sainte-Anne | Low |
154 | 888 | Jacques-Cartier | Low |
154 | 891 | Montmorency | Low |
154 | 859 | Lower St. Lawrence - Gouffre | Low |
154 | 807 | Malbaie | Low |
156 | 839 | Headwaters Saint-Maurice | Low |
156 | 833 | Upper Saint-Maurice | Low |
156 | 907 | Manouane | Low |
156 | 955 | Matawin | Low |
156 | 918 | Vermillon | Low |
156 | 854 | Central Saint-Maurice | Low |
156 | 934 | Lower Saint-Maurice | Low |
170 | 977 | Nicolet | Low |
170 | 984 | Lower Saint-François | Low |
170 | 974 | Upper Saint-François | Low |
170 | 988 | Yamaska | Low |
170 | 1003 | Lake Champlain | Low |
170 | 989 | Richelieu | Low |
170 | 1002 | St-Lawrence - île de Montréal | Low |
170 | 968 | St-Lawrence - du Loup - Lac Saint-Pierre | Low |
170 | 980 | L'Assomption | Low |
165 | 932 | Upper Ottawa-Kinojévis | Low |
165 | 929 | Upper Ottawa - Headwaters | Low |
163 | 913 | Upper Gatineau | Low |
163 | 936 | Upper Lièvre | Low |
163 | 966 | Rouge and Nord | Low |
163 | 991 | Petite Nation | Low |
163 | 995 | Lower Lièvre | Low |
163 | 987 | Lower Gatineau | Low |
167 | 981 | Dumoine | Low |
167 | 979 | Coulonge | Low |
167 | 990 | Noire | Low |
167 | St. Lawrence River east of Moose Saunders Dam | High |
Secondary Watershed Code Number | Tertiary Watershed Code Number | Name | Risk of VHSV Infection |
---|---|---|---|
157 | 994 | Pigeon | Low |
157 | 964 | Dog | Low |
157 | 952 | Black Sturgeon | Low |
157 | 860 | Nipigon | Low |
157 | 954 | Jackpine | Low |
164 | 939 | Little Pic | Low |
164 | 921 | Pic | Low |
164 | 951 | White | Low |
164 | 970 | Michipicoten-Magpie | Low |
164 | 996 | Agawa | Low |
164 | 1006 | Goulais | Low |
176 | 1026 | Garden | High |
176 | 999 | Upper Mississagi | Low |
176 | 1013 | Lower Mississagi | High |
176 | 1017 | Serpent | High |
176 | 998 | Spanish | High |
176 | 1001 | Vermillion | Low |
176 | 1027 | Killarney | High |
177 | 1037 | Manitoulin Island | High |
177 | 1035 | Magnetewan | High |
177 | 1022 | Muskoka | High |
177 | 1033 | Severn-Lake Simcoe | High |
177 | 1042 | Nottawasaga | High |
168 | 997 | Upper Wanapitei | Low |
168 | 992 | Sturgeon | Low |
168 | 1012 | Lower Wanapitei | High |
168 | 1008 | French | High |
165 | 972 | Montreal | Low |
165 | 960 | Blanche | Low |
165 | 983 | Upper Ottawa-Kipawa | Low |
167 | 1004 | Central Ottawa-Dumoine | Low |
167 | 1014 | Petawawa | Low |
167 | 1010 | Central Ottawa-Bonnechere | Low |
167 | 1020 | Upper Madawaska | Low |
167 | 1019 | Lower Madawaska | Low |
163 | 1016 | Central Ottawa-Mississippi | Low |
163 | 1007 | Lower Ottawa-South Nation | Low |
163 | 1015 | Rideau | Medium* |
172 | 1029 | Cataraqui | High |
181 | 1028 | Gull | Low |
181 | 1036 | Kawartha Lakes | Medium |
181 | 1046 | Scugog | Medium |
181 | 1041 | Otonabee | Medium |
181 | 1047 | Ganaraska | High |
181 | 1030 | Trent | High |
181 | 1031 | Moira | High |
181 | 1032 | Napanee | High |
181 | 1044 | Picton | High |
181 | 1049 | Humber-Don | High |
181 | 1052 | Credit-16 Mile | High |
181 | 1056 | Niagara | High |
180 | 1045 | Southwest Georgian Bay | High |
180 | 1040 | Bruce Peninsula | High |
180 | 1048 | Saugeen | High |
180 | 1051 | Penetangore | High |
180 | 1053 | Maitland | High |
180 | 1058 | Ausable | High |
182 | 1068 | Cedar | High |
182 | 1063 | Lower Thames | High** |
182 | 1064 | Sydenham | High |
182 | 1066 | Rondeau | High |
182 | 1054 | Upper Thames | Low |
182 | 1062 | Big | High |
182 | 1057 | Lower Grand | High |
182 | 1050 | Upper Grand | Low |
182 | 973 | Lake Superior | High |
182 | 1023 | Connection between Lakes Superior and Huron | High |
182 | 1021 | Lake Huron | Positive |
182 | 1065 | St. Clair River | Positive |
182 | 1067 | Lake St. Clair | Positive |
182 | 1069 | Detroit River | Positive |
182 | 1060 | Lake Erie | Positive |
182 | 1061 | Upper Niagara River | Positive |
182 | 1055 | Lower Niagara River | Positive |
182 | 1043 | Lake Ontario | Positive |
182 | St. Lawrence River west of Moose Saunders Dam | Positive |
* There is a direct connection with Lake Ontario through a lock system with high boat traffic (Rideau Canal Waterway).
** One positive fish was identified in the Lower Thames watershed through a sampling scheme conducted by the Ontario Ministry of Natural Resources and confirmed by the DFO-VHSV National Reference Laboratory.
Table 2: List of watersheds and fish species tested in Ontario and Québec in the spring of 2007.
Sampling Site - Watershed | Fish species (number tested) | Date Sampled | Fish Collection Method |
---|---|---|---|
Lac St. François - St. Lawrence River | Yellow perch (173) Perca flavescens |
May 7/07 | Seine |
Lac St. Louis - St. Lawrence River | Yellow perch (170) Perca flavescens |
May 14/07 | Seine |
Gentilly (Bécancour) - St. Lawrence River | Yellow perch (190) Perca flavescens |
May 14/07 | Seine |
Sampling Site - Watershed | Fish species (number tested) | Date Sampled | Fish Collection Method |
---|---|---|---|
Lake Scugog - Scugog | Yellow perch (85) Perca flavescens Spottail shiner (85) Notropis hudsonius |
May 6/07 | Minnow traps |
Lake Simcoe - Severn- LakeSimcoe | Emerald shiner Notropis atherinoides Yellow perch Perca flavescens |
May 6/07 Not tested* |
NA** |
Lake Nipissing - French | Brown bullhead (147) Ictalurus nebulosus Northern pike (2) Esox lucius Largemouth bass (10) Micropterus salmoides Pumpkinseed (12) Lepomis gibbosus (3) Rock bass (4) Ambloplites rupestris |
May 14 and 15/07 | Trap nets |
Big Creek - Big | Emerald shiners (140) Notropis atherinoides Yellow perch (14) Perca flavescens Northern pike (12) Esox lucius Freshwater drum (2) Aplodinotus grunniens Rock bass (4) Ambloplites rupestris Bluegill (6) Lepomis macrochirus |
May 28/07 | Electrofishing |
* Fish from Lake Simcoe were not tested because shipping problems delayed the arrival of the fish to DFO laboratories. Laboratory personnel determined the fish were in an advanced state of deterioration and were not suitable for testing.
** Fishing method is not available.