| 1. |
- Halvarsson, Peter, et al.
(författare)
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Gastrointestinal parasite community structure in horses after the introduction of selective anthelmintic treatment strategies
- 2024
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Ingår i: Veterinary Parasitology. - 0304-4017 .- 1873-2550. ; 326
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Tidskriftsartikel (refereegranskat)abstract
- A relatively new method to study the species richness and diversity of nematode parasites in grazing animals is to perform deep sequencing on composite samples containing a mixture of parasites. In this work, we compared species composition of strongyles in two groups of horses as a function of egg count and age, based on a DNA barcoding approach. Faecal egg counts and larval cultures were obtained from nearly 300 horses, i.e., domestic horses (n = 167) and trotters (n = 130) sampled nationwide. The second internal transcribed spacer region (ITS2) of strongyle nematodes in the larval cultures was first amplified using barcoded universal primers and then sequenced on the PacBio platform. Subsequently, bioinformatic sequence analysis was performed using SCATA to assign operational taxonomic units (OTU). Finally, species occurrence and composition were assessed using R. ITS2 sequences were found in the majority (89%) of larval samples. Sequencing yielded an average of 140 (26 to 503) reads per sample. The OTUs were assigned to 28 different taxa, of which all but three could be identified as species. The average relative abundance of the seven most abundant species (all Cyathostominae) accounted for 87% of the combined data set. The three species with the highest prevalence in both horse groups were Cyathostomum catinatum, Cylicocyclus nassatus and Cylicostephanus calicatus, and they were frequently found in different combinations with other species regardless of horse group. Interestingly, this result is largely consistent with a previous Swedish study based on morphological analysis of adult worms. In addition, two migratory strongylids (Strongylus vulgaris and S. edentatus) occurred in few domestic horses and trotters. Except for C. minutus and C. nassatus, which decreased with age, and C. catinatum and S. vulgaris, which increased, no specific trends were observed with respect to horse age. Taken together, these results are broadly consistent with data obtained before the introduction of selective targeted treatment in Sweden in 2007. All in all, our results suggest that this treatment strategy has not led to a significant change in strongyle nematode community structure in Swedish horses. The study also confirms that nemabiome analysis in combination with diversity index analysis is an objective method to study strongyle communities in horses.
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| 2. |
- Hellman, Stina, et al.
(författare)
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Equine enteroid-derived monolayers recapitulate key features of parasitic intestinal nematode infection
- 2024
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Ingår i: Veterinary research (Print). - : Springer Nature. - 0928-4249 .- 1297-9716. ; 55:1
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Tidskriftsartikel (refereegranskat)abstract
- Stem cell-derived organoid cultures have emerged as attractive experimental models for infection biology research regarding various types of gastro-intestinal pathogens and host species. However, the large size of infectious nematode larvae and the closed structure of 3-dimensional organoids often hinder studies of the natural route of infection. To enable easy administration to the apical surface of the epithelium, organoids from the equine small intestine, i.e. enteroids, were used in the present study to establish epithelial monolayer cultures. These monolayers were functionally tested by stimulation with IL-4 and IL-13, and/or exposure to infectious stage larvae of the equine nematodes Parascaris univalens, cyathostominae and/or Strongylus vulgaris. Effects were recorded using transcriptional analysis combined with histochemistry, immunofluorescence-, live-cell- and scanning electron microscopy. These analyses revealed heterogeneous monolayers containing both immature and differentiated cells including tuft cells and mucus-producing goblet cells. Stimulation with IL-4/IL-13 increased tuft- and goblet cell differentiation as demonstrated by the expression of DCLK1 and MUC2. In these cytokine-primed monolayers, the expression of MUC2 was further promoted by co-culture with P. univalens. Moreover, live-cell imaging revealed morphological alterations of the epithelial cells following exposure to larvae even in the absence of cytokine stimulation. Thus, the present work describes the design, characterization and usability of an experimental model representing the equine nematode-infected small intestinal epithelium. The presence of tuft cells and goblet cells whose mucus production is affected by Th2 cytokines and/or the presence of larvae opens up for mechanistic studies of the physical interactions between nematodes and the equine intestinal mucosa.
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| 3. |
- Höglund, Johan
(författare)
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Occurrence of gastrointestinal nematodes in lambs in Norway, as assessed by copromicroscopy and droplet digital polymerase chain reaction
- 2024
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Ingår i: Acta Veterinaria Scandinavica. - 0044-605X .- 1751-0147. ; 66
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Tidskriftsartikel (refereegranskat)abstract
- Background Gastrointestinal nematodes (GINs) have a major impact on sheep production, health, and welfare worldwide. Norway is no exception, but there are only a few studies on the prevalence of GINs in Norwegian sheep. The aim of this study was to investigate the current occurrence of the most important nematodes in sheep flocks in Norway. Faecal samples were collected from flocks in 2021/2022, mainly from three geographical regions in Norway, i.e., northern, eastern, and western. In each of 134 flocks included, individual samples from 10 lambs (autumn) were pooled. Third stage larvae (L3) were cultivated and harvested (Baermann method) from the pooled samples. The DNA was then extracted and further analysed using droplet digital PCR (ddPCR). This enables assessment of the proportions of the three most important nematode species/genera, i.e., H. contortus, T. circumcincta, and Trichostrongylus. The fractional abundance/relative proportion of each species/genus was assessed by performing duplex assays with universal strongyle and species/genus-specific primers and probe sets. In addition, the occurrence of Nematodirus eggs was assessed by standard faecal egg counts (i.e., McMaster method). Results Of the 134 flocks sampled, 24 were from the northern region, 31 from eastern, and 71 from western Norway. In addition, some flocks from central (n = 7), and southern (n = 1) Norway were included. Among the sampled flocks, T. circumcincta occurred most commonly (94%), followed by H. contortus (60%) and Trichostrongylus (55%), and Nematodirus (51%). In general, mixed infections were observed, with 38% and 18% of flocks infected with three or all four genera, respectively. Conclusions The results of this study indicate that GINs are widespread in Norway. Teladorsagia circumcincta seems to be present in most flocks based on this screening. Moreover, the results show that Nematodirus spp. infect lambs throughout the country, predominantly N. battus, and indicate that this nematode has become more abundant, which could lead to an increase in nematodirosis.
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| 4. |
- Malaluang, Pongpreecha, et al.
(författare)
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Reduced bacterial load in stallion semen by modified single layer centrifugation or sperm washing
- 2024
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Ingår i: Theriogenology. - 0093-691X .- 1879-3231. ; 216, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- The presence of bacteria poses a significant challenge to the quality of stallion semen used in artificial insemination. The bacterial content of insemination doses arises from various sources, such as the healthy stallion, environment, and collection equipment, and is implicated in fertility problems as well as reduced sperm quality during storage. The conventional approach of adding antibiotics to semen extenders raises concerns about antimicrobial resistance and potential negative effects on sperm characteristics, and may not be effective in inhibiting all bacteria. The objective of this study was to determine whether an innovative alternative to antibiotic usage – centrifugation through a single layer of a low density colloid (SLC) – could reduce the bacterial load in stallion semen, and to compare sperm characteristics in samples arising from this procedure, or simple extension of the ejaculate in semen extender, or from sperm washing, i.e. adding extender and then centrifuging the sample to allow the removal of most of the seminal plasma and extender. Eighteen semen samples were collected from six stallions. The semen samples were split and extended prior to washing or SLC, or received no further treatment other than extension. After preparation aliquots from each type of sample were sent for bacteriological examination; the remaining samples were stored for up to 72 h, with daily checks on sperm quality. The low density colloid SLC outperformed sperm washing or extension for bacterial reduction, effectively removing several bacterial species. The bacterial load in the samples was as follows: extended semen, 16 ± 6.7 × 105 ; washed, 5.8 ± 2.0 × 105 ; SLC, 2.3 ± 0.88 × 105 , p < 0.0001. In addition, SLC completely removed some bacterial species, such as Staphylococcus xylosus. Although there is no selection for robust spermatozoa with the low density colloid, sperm motility, membrane integrity, and DNA fragmentation were not different to washed sperm samples. These findings suggest that SLC with a low density colloid offers a promising method for reducing bacterial contamination in stallion semen without resorting to antibiotics.
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| 5. |
- Strage, Emma, et al.
(författare)
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Insulin release from isolated cat islets of Langerhans
- 2024
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Ingår i: Domestic Animal Endocrinology. - : Elsevier. - 0739-7240 .- 1879-0054. ; 87
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Tidskriftsartikel (refereegranskat)abstract
- Feline diabetes mellitus is a common endocrine disease with increasing prevalence. It shows similarities with human type 2 diabetes and is characterized by insulin resistance and deficient insulin secretion. Moreover, cats and humans belong to the very few species that form amyloid depositions in the pancreatic islets. However, little is known about cat islet function and no studies have addressed insulin secretion from isolated islets ex vivo. The aim of this study was to establish a protocol for isolation of islets of Langerhans from pancreata of cats euthanized due to disease, and to evaluate insulin secretion responses to various physiological and pharmacological stimuli. Collagenase digestion of pancreatic tissue from 13 non-diabetic cats and two cats with diabetic ketoacidosis yielded individual islets surrounded by a layer of exocrine tissue that was reduced after two days in culture. Histological examination showed islet amyloid in pancreatic biopsies from most non-diabetic and in one diabetic cat. Islets from non-diabetic cats cultured at 5.5 mM glucose responded with increased insulin secretion to 16.7 mM glucose, 30 mM K+ and 20 µM of the sulfonylurea glipizide (2-3 times basal secretion at 3 mM glucose). The glucagon-like peptide-1 receptor agonist exendin-4 (100 nM) had no effect under basal conditions but potentiated glucose-triggered insulin release. Only one of nine islet batches from diabetic cats released detectable amounts of insulin, which was enhanced by exendin-4. Culture of islets from non-diabetic cats at 25 mM glucose impaired secretion both in response to glucose and K+ depolarization. In conclusion, we describe a procedure for isolation of islets from cat pancreas biopsies and demonstrate that isolated cat islets secrete insulin in response to glucose and antidiabetic drugs. The study provides a basis for future ex vivo studies of islet function relevant to the understanding of the pathophysiology and treatment of feline diabetes.
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| 6. |
- Alsanius, Beatrix, et al.
(författare)
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Be circular – Från rötrester av svartvatten och köksavfall till flytande gödselmedel
- 2024
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- Effektiv användning av ändliga resurser är ett av de främsta målen för en hållbar utveckling. I ett kretsloppsperspektiv skulle näringsrikt avloppsvatten och näring fastlagd i köksavfall kunna bli till flytande gödselmedel till hobbyodlare. Vår utgångspunkt var sidoströmmar från biogasproduktion, både svartvatten (d.v.s. toalettvatten) och den flytande fraktionen av köksavfall. I ett Partnerskap Alnarp projekt mellan SLU, AlnarpFoodTech Ek. för. och RecoLab vid NSVA i Helsingborg undersökte vi bland annat förbättringsområden för att ta fram en tillförlitlig och säker växtnäringsprodukt.
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| 7. |
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| 8. |
- Arnemo, Jon
(författare)
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A Global Systematic Review of Lead (Pb) Exposure and its Health Effects in Wild Mammals
- 2024
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Ingår i: Journal of Wildlife Diseases. - 0090-3558 .- 1943-3700. ; 60, s. 285-297
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Forskningsöversikt (refereegranskat)abstract
- Lead (Pb) is a toxic nonessential metal, known mainly for causing poisoning of humans and wild birds. However, little is known about Pb exposure and its associated health effects in wild mammals. We conducted a global systematic literature review to identify peer-reviewed studies published on Pb exposure in wild mammalian species and the health effects they identified. In total, 183 studies, conducted in 35 countries and published over 62 yr (1961-2022), were included in the review. Only 6% (11/183) of the studies were conducted in developing countries. Although 153 mammalian species were studied, most studies focused on species that are easy to access (i.e., hunted species and small mammals that are easy to trap). Therefore, carnivores and scavengers were less frequently studied than herbivores and omnivores. Despite all studies reporting Pb concentrations, only 45 (25%) studies investigated health effects and, of these 45 studies, only 28 (62%) found any health effect in 57 species. All health effects were negative and ranged from subclinical effects to fatality. Methodologies of Pb sampling and quantification and reporting of results varied widely across the studies, making both Pb concentrations and health effects difficult to compare and evaluate. Thus, there is a need for more research on Pb exposure and its health effects on wild mammals, especially as carnivores and scavengers could be used as sentinels for ecosystem health.
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| 9. |
- Dube, Faruk
(författare)
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A transcriptomic tale of two worms : Evaluating Caenorhabditis elegans as a model for Parascaris univalens in drug resistance studies
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parascaris univalens, an equine roundworm, poses a significant threat to foals, potentially causing lethal intestinal ruptures in high infestations. Infection control relies on a limited arsenal of anthelmintic drugs like ivermectin (IVM). However, widespread resistance exacerbated by frequent treatments in foals, first year, challenges effective management. Research into the genetics of this resistance is vital, yet troubled by the parasite’s complex lifecycle, large size, cultivation issues, incomplete genome, and ethical and financial constraints. The free-living nematode Caenorhabditis elegans, known for its simple lifecycle and well-mapped genome, offers a promising alternative model. This thesis assessed C. elegans as a model for studying anthelmintic resistance (AR) in P. univalens and other ascarids, using transcriptomics and gene co-expression networks to bypass traditional method biases and identify novel genes referred to as “core genes”. The study exposed adult P. univalens and C. elegans to different IVM concentrations, revealing distinct genetic responses. Parascaris univalens showed core genes linked to transcriptional suppression, cell cycle inhibition, ribosomal activation, and cuticle/membrane integrity, while C. elegans exhibited diverse core gene involvement, especially upregulated heat shock proteins. Caenorhabditis elegans had more differentially expressed genes (DEGs) in xenobiotic metabolism, with Cytochrome P450s dominance compared to Short Chain Dehydrogenase/Reductases in P. univalens in Phase I. However, the response of Phase II metabolism genes was similar in both species. In addition, the P. univalens IVM response affected numerous ligand-gated ion channels compared to C. elegans, indicating species-specific differences. Despite no shared orthologous core genes and different IVM response functions, both species engaged similar gene families, highlighting C. elegans as a useful model for P. univalens AR studies. Yet, significant differences underline the necessity for supplementary, targeted research in specific parasitic nematodes, crucial for understanding AR mechanisms and developing more effective control strategies in equines.
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| 10. |
- Ekman, Stina, et al.
(författare)
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Osteochondrosis in the central and third tarsal bones of young horses
- 2024
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Ingår i: Veterinary Pathology. - 0300-9858 .- 1544-2217. ; 61, s. 74 - 87
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the central and third tarsal bones of 23 equine fetuses and foals were examined using micro-computed tomography. Radiological changes, including incomplete ossification and focal ossification defects interpreted as osteochondrosis, were detected in 16 of 23 cases. The geometry of the osteochondrosis defects suggested they were the result of vascular failure, but this requires histological confirmation. The study aim was to examine central and third tarsal bones from the 16 cases and to describe the tissues present, cartilage canals, and lesions, including suspected osteochondrosis lesions. Cases included 9 males and 7 females from 0 to 150 days of age, comprising 11 Icelandic horses, 2 standardbred horses, 2 warmblood riding horses, and 1 coldblooded trotting horse. Until 4 days of age, all aspects of the bones were covered by growth cartilage, but from 105 days, the dorsal and plantar aspects were covered by fibrous tissue undergoing intramembranous ossification. Cartilage canal vessels gradually decreased but were present in most cases up to 122 days and were absent in the next available case at 150 days. Radiological osteochondrosis defects were confirmed in histological sections from 3 cases and consisted of necrotic vessels surrounded by ischemic chondronecrosis (articular osteochondrosis) and areas of retained, morphologically viable hypertrophic chondrocytes (physeal osteochondrosis). The central and third tarsal bones formed by both endochondral and intramembranous ossification. The blood supply to the growth cartilage of the central and third tarsal bones regressed between 122 and 150 days of age. Radiological osteochondrosis defects represented vascular failure, with chondrocyte necrosis and retention, or a combination of articular and physeal osteochondrosis.
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