Weight gain and resistance to gastrointestinal nematode infections in two genetically diverse groups of cattle

Body weight gain (BWG) and gastrointestinal nematode challenge (GIN) were investigated in two genetically diverse groups of cattle. Thirty-two dairy calves (D = Swedish Red/Holstein) and 31 dairy × beef crosses (C = Swedish Red/Holstein × Charolais) pairwise matched by dam breed and birth dates, were monitored for ≈20 weeks on a pasture grazed by cattle in the previous year. At turn-out, animals (between 6 and 12 months age) from each genotype were either infected with 5000 third stage (L3) Ostertagia ostertagi (50%) and Cooperia oncophora (50%) larvae (H, high-exposure); or treated monthly with 0.5 mg ivermectin (Noromectin®, Pour-on) per kg bodyweight to remove worms ingested (L, low-exposure). Animals were weighed every fortnight and individual BWG was calculated. Faecal and blood samples were collected every four weeks throughout the experiment for nematode faecal egg counts (FEC) and larvae cultures and serum pepsinogen concentrations (SPC), respectively. Nematode eggs were observed 29 days post turn-out in both H groups. FEC peaked to around 200 eggs per gram (epg) on days 58 and 85 respectively in both H groups. FEC were also observed in the L groups at the same time, but mean epg remained very low ( 3.5 IU tyrosine whereas only six DH animals reached similar pepsinogen levels. The level of infection (H and L) significantly affected BWG in both genotypes. Even though there was no statistically sig- nificant genotype (C or D) × treatment (H or L) interaction, there was a larger difference in body weight of H and L in C (37 kg) compared to D (17 kg) genotypes at the end of the experiment. Our data collectively support the view crossbred (C) animals experience the impact of gastrointestinal parasitism more severely compared to pure dairy (D) first season grazers. The mechanisms that underpin this remains speculative

Parasitangrepp hos nötkreatur påverkas av ras

Betande nötkreatur över hela världen smittas av parasiter. Särskilt hos förstagångsbetande ungdjur påverkar maskinfektioner djurens hälsa och välfärd allvarligt. Som följd sänks produktionen vilket också ger ekonomiska förluster för lantbrukarna

Parasitologi i teori och praktik

Föreläsningsmaterial "Parasitologi i teori och praktik" av Johan Höglund

Distribution of large lungworms (Nematoda: Dictyocaulidae) in free-roaming populations of red deer Cervus elaphus (L.) with the description of Dictyocaulus skrjabini n. sp.

Lungworms of the genus Dictyocaulus are causative agents of parasitic bronchitis in domestic and wild ungulates. This study investigates the distribution, morphology and genetic diversity of D. cervi and a new lungworm species, Dictyocaulus skrjabini n. sp. infecting red deer Cervus elaphus, fallow deer Dama dama and moose Alces alces in Poland and Sweden. The study was conducted on 167 red deer from Poland and on the DNA of lungworms derived from 7 fallow deer, 4 red deer and 2 moose collected in Sweden. The prevalence of D. cervi and D. skrjabini n. sp. in dissected red deer in Poland was 31.1% and 7.2%, respectively. Moreover, D. skrjabini n. sp. was confirmed molecularly in 7 isolates of fallow deer lungworms and 1 isolate of red deer lungworms from Sweden. Dictyocaulus skrjabini n. sp. was established based on combination of their distinct molecular and morphological features; these included the length of cephalic vesicle, buccal capsule (BC), buccal capsule wall (BCW), distance from anterior extremity to the nerve ring, the width of head, oesophagus, cephalic vesicle, BC and BCW, as well as the dimensions of reproductive organs of male and female. Additionally, molecular analyses revealed 0.9% nucleotide sequence divergence for 1,605 bp SSU rDNA, and 16.5-17.3% nucleotide sequence divergence for 642 bp mitochondrial cytB between D. skrjabini n. sp. and D. cervi, respectively, and 18.7-19% between D. skrjabini n. sp. and D. eckerti, which translates into 18.2-18.7% amino acid sequence divergence between D. skrjabini n. sp. and both lungworms

Decolonising the COVID-19 pandemic: On being in this together

At its inception, the COVID-19 pandemic was described as something inherently new, capable of crossing and erasing the economic, racial, gendered, and religious divides that stratify societies around the world. However, the ongoing pandemic is not new or egalitarian, but fuelled by, and fuelling, crises already under way on a global scale. In this article we examine on the one hand the relationship between the pandemic and still-active formations of racialised and gendered power, and on the other the pandemic's inextricability from a dispersed and uneven planetary emergency. As the environmental historian Jason W. Moore notes, this emergency disproportionately affects ‘women, people of colour and (neo)colonial populations’ (2019: 54), and the effects of COVID-19 are similarly unevenly allocated

Digital PCR: modern solution to parasite diagnostics and population trait genetics

The use of polymerase chain reaction (PCR)-based diagnostic approaches has steadily increased in the field of parasitology in recent decades. The most recent large-scale technological modification of the PCR formula, also known as third-generation PCR, came in the form of digital PCR (dPCR). Currently, the most common form of dPCR on the market is digital droplet PCR (ddPCR). Unlike quantitative real-time PCR (qPCR), the digital format allows for highly sensitive, absolute quantification of nucleic acid targets and does not require external standards to be included in the developed assays. Dividing each sample into thousands of compartments and using statistical models also eliminates the need for technical replicates. With unprecedented sensitivity and enforcement of binary endpoint reactions, ddPCR not only allows the use of tiny sample volumes (especially important when working with limited amounts of DNA) but also minimises the impact of variations in amplification efficiency and the presence of inhibitors. As ddPCR is characterised by excellent features such as high throughput, sensitivity and robust quantification, it is widely used as a diagnostic tool in clinical microbiology. Due to recent advances, both the theoretical background and the practical, current applications related to the quantification of nucleic acids of eukaryotic parasites need to be updated. In this review, we present the basics of this technology (particularly useful for new users) and consolidate recent advances in the field with a focus on applications to the study of helminths and protozoan parasites

Anthelmintic Treatment of Sheep and the Role of Parasites Refugia in a Local Context

Simple Summary The control of gastrointestinal parasites in sheep is often based on the integrated use of anthelmintics and pasture management. As problems with resistance to anthelmintics become more common, it is important to consider the timing of treatment. This is because one way to delay selection for anthelmintic resistance is to take into account that there are susceptible parasites in refugia that are not selected for treatment. In Sweden, stabled ewes are sometimes treated before being let out to pasture with their lambs in the spring. It is thought that this may increase selection for resistance. However, unlike in many other parts of the world, in Sweden, treatment is usually motivated by large numbers of worm eggs detected in faecal samples. In this review, we discuss whether the Swedish model is a risky strategy. In doing so, we consider the experience from several studies conducted in Sweden and abroad. We conclude that the evidence is inconclusive. Moreover, there are gaps in our knowledge, not least regarding the genetic background of resistance formation and how this is influenced by refugia. Further fundamental work is therefore needed on this topic. Gastrointestinal nematodes in grazing livestock are ubiquitous and can cause severe damage, leading to substantial losses in agricultural yields. It is undeniable that the integrated use of anthelmintics is often an essential component of successful intensive livestock management. However, anthelmintic resistance has been a major challenge for several decades, especially in pasture-based lamb production. Measures are therefore needed to reduce the risk and prevent further spread. In many countries with more extensive lamb production and pronounced resistance problems than in Sweden, the importance of keeping parasites in refugia is emphasised. To ensure that treatment is necessary, the Swedish model is based on deworming certain groups of ewes based on the parasitological results of a faecal examination and then releasing them with their lambs to safe pastures. This is intended to reduce the risk of infection, which ultimately reduces the number of subsequent treatments. Whether this preventive strategy in turn means an increased risk of resistance is debatable. In this review, we explain the importance of parasites in refugia and how they can help delay the development of resistance to anthelmintics. We also discuss how likely it is that our model contributes to an increase in resistance risk and whether there is reason to question whether it is a sustainable strategy in the long term

Taenia lynciscapreoli in semi-domesticated reindeer (Rangifer tarandus tarandus, L.) in Sweden

We report here Taenia lynciscapreoli metacestode from the lung lobe of a semi-domesticated reindeer (Rangifer tarandus tarandus). The specimen was detected within a development project concerning remote post mortem inspection at a reindeer abattoir in Sweden. Post mortem inspection was performed according to a routine on-site official meat inspection protocol. The species identification to T. lynciscapreoli was confirmed based on the DNA extracted from the metacestode, which was analysed by sequencing of the cytochrome c oxidase subunit 1. Firstly, our finding shows that semi-domesticated reindeer in addition to several other cervids can act as an additional intermediate host for T. lynciscapreoli. Secondly, it further confirms that this parasite is more widely distributed on the Scandinavian peninsula than what has previously been shown. This is in line with a previous molecular finding of adult T. lynciscapreoli from the Eurasian lynx (Lynx lynx) in Sweden and demonstrates that new intermediate host can be detected. Whether the present finding can be regarded as accidental or have created opportunities for an expansion throughout the northernmost Scandinavian Peninsula remains to be seen.We report here Taenia lynciscapreoli metacestode from the lung lobe of a semi-domesticated reindeer (Rangifer tarandus tarandus). The specimen was detected within a development project concerning remote post mortem inspection at a reindeer abattoir in Sweden. Post mortem inspection was performed according to a routine on-site official meat inspection protocol. The species identification to T. lynciscapreoli was confirmed based on the DNA extracted from the metacestode, which was analysed by sequencing of the cytochrome c oxidase subunit 1. Firstly, our finding shows that semi-domesticated reindeer in addition to several other cervids can act as an additional intermediate host for T. lynciscapreoli. Secondly, it further confirms that this parasite is more widely distributed on the Scandinavian peninsula than what has previously been shown. This is in line with a previous molecular finding of adult T. lynciscapreoli from the Eurasian lynx (Lynx lynx) in Sweden and demonstrates that new intermediate host can be detected. Whether the present finding can be regarded as accidental or have created opportunities for an expansion throughout the northernmost Scandinavian Peninsula remains to be seen