Wild animal disease monitoring

Evira's wildlife disease surveillance

Wildlife disease surveillance  includes two basic components, the targeted, or active, surveillance, and the general, or scanning, surveillance.

Examinations concerning terrestrial wild animals (including birds) are performed at Evira's Production Animal and Wildlife Health Research Unit in Oulu. In addition to Oulu, fish disease examinations are also performed at the Production Animal and Wildlife Health Research Unit in Helsinki and Kuopio.

The Oulu unit is a national reference laboratory for parasitology. The Kuopio unit is the World Organisation for Animal Health's (OIE) reference laboratory for crayfish plague. The Veterinary Virology Research Unit in Helsinki performs all viral disease research at Evira.

1. Targeted surveillance

In targeted surveillance, an annual plan is made on the aimed quantity of samples and the regional allocation, taking into account the resources available for the purpose.


Small predators, mostly foxes and raccoon dogs, are collected as samples in collaboration with regional Finnish Wildlife Agency offices and local hunters. The main target area is the rabies bait vaccination zone on the south-eastern border, but, resources allowing, samples from other areas can also be examined in certain years.

A virological examination for rabies is performed on the brain samples. Samples from the vaccination zone are examined to monitor the coverage of the vaccination campaign by testing for the presence of rabies antibodies in animal blood and vaccine biomarkers (tetracycline) in tooth and jawbone samples. In addition, any suspected cases of rabies in wild animals are examined if the animal's behaviour may be indicative of rabies.

Echinococcus multilocularis

Foxes and raccoon dogs are collected as samples in collaboration with regional Finnish Wildlife Agency offices and local hunters. The sample animals are partly the same as in surveillance of rabies, but the sampling area is larger, the focus being on Southern Finland. The purpose of monitoring is to show that Finland is free from the disease, so that the special requirements concerning the import of pets can be held in force: no anti-echinococcus treatment is required of dogs travelling to Finland from Norway, the United Kingdom, Ireland or Malta. Intestinal content is taken as sample for the identification of potential echinococcus DNA.


In Trichinella surveillance, samples are collected from carnivorous mammals from every part of the country. Bird species eating carcases are also examined for trichinellosis caused by nematode larvae of the genus Trichinella.

Samples originate from the material collected for the general disease surveillance as well as from the Natural Resources Institute Finland (Luke), where hunted large predators are handled. The assay is based on the examination of muscle tissue samples by digestion methodology, where meat is digested using a method equivalent to digestion in the stomach, and any Trichinella larvae found are identified using multiplex PCR technique. Four different Trichinella species have been found in Finland: Trichinella spiralis, Trichinella nativa, Trichinella britovi and Trichinella pseudospiralis.

Information on the relative abundance of Trichinella species and potential changes thereof is collected and can be applied to assessing the external infection pressures towards and routes of infection to pig farms.

Gyrodactylus salaris

Gyrodactylus salaris monitoring is performed in water body areas that drain to the Arctic Ocean, and in the River Tornionjoki catchment area. Wild Atlantic salmon parr and fin samples of other wild fishes are collected as samples with the help of electrofishing conducted by the Natural Resources Institute Finland and rod and line byprivate fishermen. The fins are examined by direct microscopic method and the species determination of the parasites found is done using PCR methodology.

The EU Commission has granted Finland additional fish-health guarantees for the prevention of the spread of the salmon parasite Gyrodactylus salaris to the breeding grounds of the wild Atlantic salmon in the rivers Tenojoki and Näätämöjoki. The additional guarantees allow the prevention of fish transfers from dangerous water body catchmentareas to these rivers. Further regulation on the protection of these rivers is included in the treaty between Finland and Norway.

Monitoring is also used for examining the parasitic situation in the buffer zone consisting of the river catchments of the rivers Tuulomajoki and Paatsjoki and the River Tornionjoki, the most important salmon river of the Baltic Sea region.

Monitoring of viral diseases and bacterial kidney disease (BKD) in wild brood fish

Samples are taken from wild brood fish in connection with the collection of roe. The focus of research is in Northern Finland. The presence of bacterial kidney disease (BKD) is analysed using bacterial cultures or ELISA methodology. Viral disease samples, on the other hand, are examined using virological methods.

The Natural Resources Institute Finland  bears the main responsibility for the recovery of endangered fish stocks in the built or otherwise altered Finnish water bodies. In connection with the preservation of the genetic material of valuable wild fish stocks, Evira monitors the occurrence of the viral diseases and BKD. The purpose of the monitoring measures is to ensure that the valuable fish stocks remain free of these contagious fish diseases.

Monitoring of diseases in wild boars

Organ and blood samples are collected from hunted wild boars for virological and bacteriological examinations (African swine fever ASF, classical swine fever CSF, Aujeszky’s disease AD and brucella). The goal is to have a pathological examination performed on any wild boars found dead or displaying symptoms of a disease.

2. General surveillance for wildlife pathogens

In general surveillance, wild animals found dead or put down due to a disease are collected as random samples. The objective is to stay up to date on which infectious diseases occur in Finland and detect in good time any outbursts of epidemics or new diseases. The regional distribution of samples depends on local mortality rates. 

Several parties, including hunters, fishermen and active nature enthusiasts, the Natural Resources Institute Finland (Luke), the municipal Centres for Economic Development, Transport and the Environment (ELY Centres), environmental authorities and, in case of suspected crimes, the police deliver samples for general surveillance. Ordinary citizens often send animals found dead in the home yards and urban areas for examination.

To specify the cause of death, histological, bacteriological, parasitological and virological examinations are performed on the basis of visual examination and other examination findings related to the autopsy. Molecular biology methods are used for the determination of different pathogens.

In addition to determining the cause of death, samples taken for general disease monitoring are used for monitoring the occurrence of several infectious diseases harmful to human or animal health. Such diseases include the avian influenza, avian paramyxoviruses, avian coronaviruses, bat rabies, bat coronaviruses, trichinellosis, salmonellosis, rabbit fever, psittacosis (parrot fever, or ornithosis), African swine fever, and chronic wasting disease (CWD) of deer.

Wild fish

Mass deaths of wild fish are examined in all locations of Evira's Production Animal and Wildlife Health Research Unit performing fish disease research (Oulu, Kuopio and Helsinki). Usually such cases are investigated in collaboration with the local ELY Centre that takes care of the examinations related to water quality and environmental conditions.


All investigations of mass deaths of crayfish are performed by the Kuopio unit. The primary focus is on crayfish plague research. The Kuopio unit is the only OIE reference laboratory in Finland and its crayfish specialist the only Finnish OIE disease specialist. The mycological diagnostic methods used include cultivation and molecule biology identification methods.

Large predators (bear, wolf, lynx, wolverine)

The causes of death of large predators and any zoonoses (diseases transmitted between humans and animals) found in them are monitored in collaboration with the game research division of the Natural Resources Institute Finland (Luke). Any animals killed by traffic, found dead in the field, and animals put down due to exceptional behaviour or symptoms of a disease are sent to Evira for examination. In addition to its own samples, Evira takes also tissue samples needed by the game research division of the Natural Resources Institute Finland. Reciprocally, the Natural Resources Institute Finland delivers any samples Evira may need for further examinations from hunted large predators sent to Luke for examination.


Evira is involved in the Helsinki Commission's HELCOM programme (HELCOM ad hoc Seal Expert Group) that monitors the health of the Baltic Sea grey seals and the ringed seals. The causes of death and diseases of the endangered Saimaa ringed seal are monitored in collaboration with Metsähallitus.

Requests for executive assistance from the police

Samples related to suspected violations of hunting or environmental protection laws are delivered to Evira by the police as requests for executive assistance. Evira determines the cause of death of the animal in question and assesses the time of death. Sometimes suspicions of criminal activity arise from an animal sent for normal post-mortem examination. In the event that suspicions lead to a trial, Evira's pathologists act as witnesses in accordance with the orders issued by the court of law.


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