Botfly Cephenemyia ulrichii larvae in the nasal cavity and nasopharynx of a dog with respiratory signs.

A Finnish Lapphund dog with acute upper respiratory signs and gagging was presented at veterinary clinic. During rhinoscopy, ten 1- to 2-mm long, actively moving larvae were found in the dog's nasal cavity and nasopharynx and identified as Cephenemyia ulrichii (Diptera: Oestridae). This moose (Alces alces) parasite is widespread in Finland but has not been reported before from an accidental canine host. Clinical signs resolved with imidacloprid/moxidectin spot-on formulation.

Molecular identification of Taenia spp. in the Eurasian lynx (Lynx lynx) from Finland.

Cestodes of the genus Taenia are parasites of mammals, with mainly carnivores as definitive and herbivores as intermediate hosts. Various medium-sized cats, Lynx spp., are involved in the life cycles of several species of Taenia. The aim of the present study was to identify Taenia tapeworms in the Eurasian lynx (Lynx lynx) from Finland. In total, 135 tapeworms from 72 lynx were subjected to molecular identification based on sequences of 2 mtDNA regions, the cytochrome c oxidase subunit 1 and the NADH dehydrogenase subunit 1 genes. Available morphological characters of the rostellar hooks and strobila were compared. Two species of Taenia were found: T. laticollis (127 samples) and an unknown Taenia sp. (5 samples). The latter could not be identified to species based on mtDNA, and the rostellar hooks were short relative to those described among other Taenia spp. recorded in felids from the Holarctic region. In the phylogenetic analyses of mtDNA sequences, T. laticollis was placed as a sister species of T. macrocystis, and the unknown Taenia sp. was closely related to T. hydatigena and T. regis. Our analyses suggest that these distinct taeniid tapeworms represent a putative new species of Taenia. The only currently recognized definitive host is L. lynx and the intermediate host is unknown.

Impaired efficacy of ivermectin against Parascaris equorum, and both ivermectin and pyrantel against strongyle infections in trotter foals in Finland.

In order to assess the resistance situation against macrocyclic lactones in Parascaris equorum and against tetrahydropyrimidine derivatives in strongyles in Finnish trotter horses, 112 foals on 18 farms, mostly 1 year old, were examined for these parasites with a modified McMaster faecal flotation method. P. equorum positive foals (n=24) were given ivermectin orally at a dose of 200 µg/kg b.w., while strongyle positive but P. equorum negative foals (n=38) received pyrantel embonate orally at a dose of 19 mg/kg. Sixteen P. equorum infected foals, treated with ivermectin, also harboured strongyles. During the anthelmintic treatment visit to the farm, Faecal Egg Count Reduction Test (FECRT) reference (first) samples were collected. Fourteen days later, the second sampling (reduction samples) was done. The FECR was calculated for each foal/parasite combination. The reduction efficacies of ivermectin against P. equorum (mean 52%, calculated from the individual egg count reductions) and pyrantel against strongyles (43%) were strongly indicative of widespread resistance. Also indication of ivermectin resistance among strongyles was seen. The widespread use of anthelmintics for Finnish horses obviously has resulted in resistance, as has happened elsewhere, too.

Genetic relationships among Trichinella pseudospiralis isolates from Australian, Nearctic, and Palearctic regions.

The study of the genetic polymorphism of pathogens is important for phylogenetic and biogeographic studies and, in the case of foodborne pathogens, to trace the origin of food infection. Since its discovery in 1972, the nonencapsulated species Trichinella pseudospiralis has been detected in mammals and birds, and human infection has occurred, in some cases resulting in death. We studied DNA polymorphism among ten T. pseudospiralis isolates from the Palearctic, Nearctic, and Australian regions, screening the sequences of nine genes [18sRNA, a random amplified polymorphism DNA derived sequence, mitochondrial cytochrome oxidase subunit I (COI), cytochrome P450, cynate lyase, epithelial fusion failure-1, and three unknown genes of Tp3, Tp8, and Tp26]. A high identity of sequence for the nine gene loci was obtained among the seven isolates from the Palearctic region and between the two isolates from the Nearctic region. Genetic identity analysis indicated the distinct polymorphism among the three geographical origins. To easily identify T. pseudospiralis genotypes, a polymerase chain reaction-restriction fragment length polymorphism analysis of COI gene was performed, and the results confirmed the DNA polymorphism within T. pseudospiralis, corresponding to the three regions of origin. We have named the three genotypes as "T. pseudospiralis Palearctic genotype" (code T4P), "Nearctic genotype" (code T4N), and "Australian genotype" (code T4A). To further investigate polymorphism among the nonencapsulated Trichinella species, the sequences of four gene loci (COI, P450, cynate lyase, and SB147D) of T. pseudospiralis, T. papuae, and T. zimbabwensis were analyzed, and the results showed high polymorphism among the three species, strongly supporting their classification as separate species.

Comparative analysis of Trichinella spiralis and Trichinella nativa proteins by two-dimensional gel electrophoresis.

Trichinella spiralis and Trichinella nativa are both common wildlife parasites in Finland. However, they differ substantially in their resistance to below 0 degrees C temperatures in their natural hosts. T. nativa can live in frozen fox meat for years, whereas T. spiralis dies when frozen. In mouse muscle, the difference is not as evident; even T. nativa cannot maintain infectivity when kept at -20 degrees C for 1 week. Crude larval protein extracts of these two parasite species were analyzed by two-dimensional gel electrophoresis (2DE). The protein patterns showed clear differences, but matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) peptide mass fingerprint followed by database searches failed to identify these proteins, suggesting that they may still be uncharacterized. The patterns compared after freezing treatment at -20 degrees C revealed changes in the intensity of some protein spots. The antigenic differences of the species were analyzed with two-dimensional Western blots, which showed T. spiralis-specific proteins.

Trichinella nativa and T. spiralis induce distinguishable histopathologic and humoral responses in the raccoon dog (Nyctereutes procyonoides).

Three experimental groups of six male raccoon dogs (Nyctereutes procyonoides) each were formed by placing one of three littermates from six litters into each group. One group was inoculated with pig-origin Trichinella spiralis, the second was inoculated with raccoon dog-origin T. nativa, and the third served as a control group. The infective dose was 1,000 larvae/kg of body weight. Every third week, biopsies from M. triceps brachii were taken, and serum samples were collected for up to 12 weeks postinfection. In the early phase of the infection, cysts of both parasites were elongated cylinders that later became more spherical. However, at the end of the experiment, the cysts of T. nativa were more rounded than those of T. spiralis (mean length/width = 2.5 versus 1.5 in T. spiralis versus T. nativa, respectively). Both species accumulated a collagen-rich capsule around the nurse cell, but the capsule was thicker in T. nativa. In both parasites, the total surface area of the sagittal section of the cyst was equal. Inflammation was more intense around T. nativa cysts. Specific antibodies were recognizable 2 weeks after infection by both enzyme-linked immunosorbent assay (ELISA) and western blot. In western blots, serum from both T. nativa- and T. spiralis-infected animals recognized the same components, but reaction with the homologous antigen was stronger. The same pattern was also seen in the ELISA. Immunoreactive epitopes were localized only in internal organs and cuticula of larvae in muscle.

Trichinellosis in farmed wild boar: meat inspection findings and seroprevalence.

A reflection of highly prevalent endemic wildlife trichinellosis is seen in wild boar farming in Finland. During the last five years, 0.7% (15/2265) of wild boars undergoing official meat inspection have been determined to be Trichinella-positive. These findings originate from six different farms. In Finland, T. spiralis and T. pseudospiralis have been discovered in meat inspection of wild boars. ELISA showed 11 out of 99 serum samples (11%) as having specific antibodies for T. spiralis crude antigen. Positive samples were from three out of the thirteen farms from which the sera were available. Most of the positive serum samples (8/11) originated from a farm where trichinellosis was also revealed in meat inspection, the other two seropositive farms were without previous Trichinella records. Over the last few decades, no reports have been made of human trichinellosis acquired in Finland. This indicates both efficient meat inspection as well as public awareness of high-risk foodstuff.

Predilection muscles and physical condition of raccoon dogs (Nyctereutes procyonoides) experimentally infected with Trichinella spiralis and Trichinella nativa.

The predilection muscles of Trichinella spiralis and T. nativa were studied in 2 experimental groups of 6 raccoon dogs (Nyctereutes procyonoides), the third group serving as a control for clinical signs. The infection dose for both parasites was 1 larva/g body weight. After 12 weeks, the animals were euthanized and 13 sampling sites were analysed by the digestion method. Larvae were found in all sampled skeleton muscles of the infected animals, but not in the specimens from the heart or intestinal musculature. Both parasite species reproduced equally well in the raccoon dog. The median density of infection in positive tissues was 353 larvae per gram (lpg) with T. spiralis and 343 lpg with T. nativa. All the infected animals had the highest larvae numbers in the carpal flexors (M. flexor carpi ulnaris). Also tongue and eye muscles had high infection levels. There were no significant differences in the predilection sites between these 2 parasite species. Trichinellosis increased the relative amount of fat, but not the body weight in the captive raccoon dogs. Thus, Trichinella as a muscle parasite might have catabolic effect on these animals.

Clinical features of experimental trichinellosis in the raccoon dog (Nyctereutes procyonoides).

Three groups of six raccoon dogs (Nyctereutes procyonoides) were provided for the experiment: the first group was infected with pig-origin Trichinella spiralis, the second with raccoon dog-origin Trichinella nativa, and the third served as controls. Infection dose for both parasite species was 1000 larvae/kg of body weight, which led to intense final infection. Clinical signs, haematology and serum biochemistry with repeated blood samples were monitored up to 12 weeks post-infection. The most significant findings were a short-term eosinophilia in peripheral blood from the end of the first week post-infection until the end of the third week, loss of weight, and mild anaemia. In the early phase of the infection, the animals had gastrointestinal signs, loss of appetite and diarrhoea. No specific differences in clinical findings could be noticed between the groups infected with T. nativa and T. spiralis. In contrast to the symptoms reported in human outbreaks, fever was not observed in any of the infected animals and serum levels of muscle-specific enzymes did not change. No acute-phase response was observed in the enteral or parental phase of the infection. These findings indicate that because Trichinella spp. are very well adapted to the raccoon dog, it thus, could serve as the most crucial reservoir animal for sylvatic trichinellosis in Finland.