The present contribution is the first record of ornamental freshwater shrimp Caridina babaulti from European open waters and the first evidence of introduction outside its native range. Among 120 non-native freshwater shrimps collected in Miskolctapolca, Hungary, seven individuals (5.8%) were identified as C. babaulti and included one ovigerous female, while the others (94.2%) were Neocaridina davidi. Morphological analysis and the Standard DNA Barcoding Procedure confirmed the taxonomic identification of the two species. The presence of C. babaulti in Miskolctapolca is most likely due to intentional or unintentional releases by aquarium owners. The low number of captured individuals and this species’ absence in a previous survey suggest that the shrimp is of recent introduction. C. babaulti and the well-established N. davidi have similar environmental tolerance; hence, this species might potentially form a viable population if not removed.

The aquaculture industry is growing and includes the farming and breeding of more than 580 aquatic species worldwide. The rainbow trout (Oncorhynchus mykiss, Walbaum 1792) is the most commonly bred trout species in Hungary. As broodfish form the basis of most fish farms, investigation into tumours occurring in trout, although under‐researched, has proven to be a valuable and necessary field of study. During our investigation, we examined a broodstock of 3‐ to 6‐year‐old rainbow trouts (800) affected with idiopathic intestinal tumours (3%) which had consequentially led to ileus (40%). While performing necropsy, initial pathological observations showed intussusceptions. Tumours were discovered upon opening the body cavity, as well as metastasis forming in the livers and in the vessels of the gills. Histopathological and immunohistochemical tests allowed us to identify the neoplasms. The primary adenocarcinoma was found to have been developed within the intestines of the fish. The tumour tissue broke through the basal membrane and infiltrated the propria, protruding asymmetrically into the lumen of the mid‐intestines, causing it to narrow significantly. This subsequently led to passage disorders, invagination of the intestinal segment and finally the emaciation of the fish. Histopathological and immunohistochemical inspection of the tumour cells displayed a high mitotic index, confirming malignancy.

The genus Erinaceus is commonly found in rescue centres across the European continent despite the reported decline in some countries. Parasite infections are frequently detected in rescued hedgehogs, leading to increased morbidity and mortality and consequently conditioning their recovery. Some of the most frequent parasites include respiratory nematodes, such as Crenosoma striatum and Capillaria spp., which may lead to important pneumonia. Moreover, some of these agents have zoonotic potential, such as Cryptosporidium spp., Sarcoptes spp., and several species of ticks and fleas, which may transmit different vector-borne pathogens. This review provides a brief guide on hedgehogs’ internal and external parasitology, as well as some suggestions for diagnosis and treatment that are relevant for wildlife veterinarians, biologists and other researchers.

Diagnostic imaging techniques provide a new aspect of the ante‐mortem and post‐mortem diagnostics in fish medicine. Ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI) can provide more information about the internal organs and pathognomic lesions. The authors used diagnostic imaging techniques to evaluate and describe the neoplastic malformation in a 3‐year‐old female rainbow trout (Oncorhynchus mykiss). The fish was examined with Siemens Somatom Definition AS + CT scanner and Siemens Biograph mMR scanner. The animal was lethargic and showed anorectic signs and muscular dystrophy. During the post‐mortem investigation, histopathology and immunohistochemistry were also performed allowing us to identify the neoplasms. The results showed a large soft tissue mass in the first mid‐intestine segment, which proved to be an adenocarcinoma. This subsequently led to digestion problems and absorption disorders. Immunohistochemically, neoplastic cells of carcinoma revealed E‐cadherin and pancytokeratin positivity. This is the first study to report the use of MRI and CT for studying gastrointestinal adenocarcinoma in rainbow trout.

Hedgehogs, Erinaceus spp., are commonly admitted to rescue centres in European countries. However, there are still few studies on parasitological fauna and treatment possibilities, including for E. roumanicus. This study aimed to evaluate parasitism in 34 hedgehogs directly after their admission to the Budapest Zoo and Botanical Garden Wildlife Rescue Centre, as well as the efficacy of fenbendazole treatment. The Mini-Flotac method was used to quantitatively evaluate and assess the efficacy of treatment with fenbendazole (100 mg/kg PO. BID for 7 days) in five selected individuals. Faecal samples were analysed at D0 and D14 after the beginning of the treatment. Globally, the prevalence of positive animals was 76%. Capillaria spp. were the most prevalent (68%), while coccidia showed a prevalence of 32%. Considering the range of action of this benzimidazole, the treatment provided an efficacy of 100%, eliminating all forms of Capillaria spp. Considering the high number of hedgehogs admitted to rescue centres and the potential effects of parasitism in morbidity and mortality during recovery, it is essential to improve our knowledge with regard to the parasitological fauna of these species and to attain effective treatment protocols.

Acipenserid species play an important role in aquaculture. Emerging viral diseases can cause high mortality on farms. During our investigations, Siberian sturgeon herpesvirus (SbSHV) was detected on a fish farm in Hungary rearing Russian sturgeon ( Acipenser gueldenstaedtii ) and Siberian sturgeon ( Acipenser baerii ). Herpesvirus infection may result in mortality rates up to 100% in young animals; on the other hand, adults usually suffer much less mortality. The affected fingerlings initially showed neurological symptoms and lost their appetite. Opaque deposits and haemorrhages were observed on the skin. After necropsy, samples were taken for virological and bacteriological investigation. A broad-spectrum PCR, developed for the detection of acipenserid and ictalurid herpesviruses (genus Ictavirus ), was applied. The sequence analysis of the detected PCR fragment showed high identity to a previously described SbSHV strain originating from Russia. There is currently neither a cure nor an effective vaccine available on the market against this disease. Therefore, prevention and strict biosecurity protocols are the most important ways to keep the animals healthy.