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Sedan 1970-talet har gråsäl (Halichoerus grypus), knubbsäl (Phoca vitulina) och vikare (Phoca hispida) insamlats och undersökts på Naturhistoriska riksmuseet (NRM). Majoriteten av de undersökta sälarna är gråsälar. Beroende på jakt under 1900-talet och nedsatt reproduktion under århundradets senare del så minskade sälpopulationerna i Östersjön. Under 1970-och 1980-talet noterades ett antal sjukliga förändringar som kallades Baltic Seal Disease Complex framför allt hos gråsäl och som misstänktes ha samband med höga halter av miljögifter som PCB och DDT. Förekomsten av flera av dessa förändringar liksom halterna av PCB och DDT har minskat sedan dess. Hos gråsäl har därefter förekomst av tarmsår ökat och minskat, späcktjockleken minskat och förekomst av leverparasiter ökat. Under år 2015 insamlades och undersöktes sälar och prover från 137 gråsälar, 44 knubbsälar och 27 vikare. I övrigt inrapporterades 196 döda sälar funna på stränder av allmänheten. Gråsälspopulationen ökar för närvarande med ca 8% per år och 85% av de undersökta honorna mellan 6-24 år var dräktiga. Knubbsälspopulationerna ökar för närvarande med 7-9% per år. Antal undersökta knubbsälar var visserligen betydligt färre än antal undersökta gråsälar men andel dräktiga honor i motsvarande åldersgrupp var endast 57%. Vikarepopulationen i Bottenviken ökar för närvarande med ca 4,5% per år. Hos vikare inkom endast en könsmogen hona från dräktighetsperioden och hon var dräktig. Av de undersökta vikarna var 20 av 27 yngre än 4 år gamla. Två två-åriga vikarhonor hade missbildningar i form av diafragmabråck hos den ena och avsaknad av ett livmoderhorn hos den andra. Sammanfattningsvis ser hälsosituationen för undersökta gråsälar i Östersjön delvis bättre ut än tidigare och populationstillväxten har varit stabil under de senaste 15 åren. Antal undersökta knubbsälar och vikare är för få för att redovisa patologiska trender men undersökta knubbsälar visade tendens till låg dräktighetsfrekvens som bör studeras när, Since the 1970s, grey seals (Halichoerus grypus), harbour seals (Phoca vitulina) and ringed seals (Phoca hispida) have been collected and necropsied at the Swedish Museum of Natural History. Mostly have grey seals been examined. The effect of hunting during 19th century and reproductive failure during the latter half of the century decreased Baltic seal populations. In the 1970s and 1980s, pathological changes found mostly in grey seals was called the Baltic Seal Disease Complex and was thought to be related to high levels of PCB and DDT. Since then several pathological changes have decreased in prevalence as well as levels of PCB and DDT. Since then in grey seals, the prevalence of intestinal ulcers has increased and then decreased, blubber thickness has decreased and the prevalence of a zoonotic biliary trematode infection increased. In 2015, whole bodies and samples from 137 grey seals, 44 harbour seals and 27 ringed seals were examined at the museum. The public reported 196 seals found dead along the Swedish coast. At present, the Baltic grey seal population increases with 8% each year and 85% of the examined females 6-24 years old were pregnant during the pregnant period (August-February) in 2015. The harbour seal populations presently increase with 7-9 % per year, although the numbers of examined harbour seals are much lower than the number of grey seals, the proportion of examined pregnant harbour seals in corresponding age group was only 57%. The ringed seal population in the Gulf of Bothnia presently increase with 4,5% per year. One mature female examined from the period of pregnancy was pregnant. Of the examined 27 ringed seals, 20 of them were younger than 4 years. Two two-year old females showed malformations as diaphragmatic hiatus in one of them and the other female lacked one of the uterine horns. In conclusion, the health situation for examined Baltic grey seals is better and the increase in the population during the last 15 years is stable. The nu, Sälpatologi

The biliary trematode Pseudamphistomum truncatum parasitizes a wide range of fish-eating mammals, including humans. Here we report the emergence of this parasite in grey seals (Halichoerus grypus) in the Baltic Sea. One hundred eighty-three of 1 554 grey seals (11.9%) examined from 2002–2013 had detectable hepatobiliary trematode infection. Parasite identification was confirmed as P. truncatum by sequencing the ITS2 region of a pool of five to 10 trematodes from each of ten seals collected off the coast of seven different Swedish counties. The proportion of seals parasitized by P. truncatum increased significantly over time and with increasing age of seals. Males were 3.1 times more likely to be parasitized than females and animals killed in fishery interactions were less likely to be parasitized than animals found dead or hunted. There was no significant difference in parasitism of seals examined from the Gulf of Bothnia versus those examined from the Baltic Proper. Although the majority of infections were mild, P. truncatum can cause severe hepatobiliary disease and resulted in liver failure in at least one seal. Because cyprinid fish are the second intermediate host for opisthorchiid trematodes, diets of grey seals from the Baltic Sea were analysed regarding presence of cyprinids. The proportion of gastrointestinal tracts containing cyprinid remains was ten times higher in seals examined from 2008 to 2013 (12.2%) than those examined from 2002 to 2007 (1.2%) and coincided with a general increase of trematode parasitism in the host population. The emergence and relatively common occurrence of P. truncatum in grey seals signals the presence of this parasite in the Baltic Sea ecosystem and demonstrates how aquatic mammals can serve as excellent sentinels of marine ecosystem change. Investigation of drivers behind P. truncatum emergence and infection risk for other mammals, including humans, is highly warranted., Patologi hos säl