Assessment of worm control practices recommended by equine veterinarians in Australia

This study aimed to assess Australian veterinarians’ knowledge, perceptions and treatment strategies for worm control in horses with an online questionnaire. The questionnaire comprised 64 questions covering various aspects of: (i) veterinary practice; (ii) the veterinarian’s knowledge of gastrointestinal nematodes (GINs) and the importance of parasites in different age groups of horses; (iii) the diagnosis and control of worms; (iv) anthelmintics and anthelmintic resistance (AR); (v) grazing management; and (vi) the means of communication and the discussion between veterinarians and their clients regarding worm control. Following a pilot survey, a link for the questionnaire survey was sent to all (n = 1,148) registered members of Equine Veterinarians Australia in April 2020. The response rate for the questionnaire was 10% (118 of 1,148). The findings of this study illustrate veterinarians’ good understanding of aspects of equine parasites, including control. However, respondents mainly recommended frequent, interval-based prophylactic deworming in young horses, and only 40% (96 of 239) diagnosed GIN infections based on faecal egg count (FEC) results in all age groups of horses. Furthermore, only 27% (88 of 330) of the respondents made deworming decisions based on FECs. Most of the respondents recommended macrocyclic lactones (MLs) for all age groups of horses (71%, 481 of 677), and the most frequently used method to calculate the dose of anthelmintics was by estimating the weight of animals visually (53%, 63 of 118). Although the majority of respondents (97%, 115 of 118) perceived AR to be a critical issue in managing worms in horses, 58% (67 of 118) of them were unaware of the status of AR on their clients’ properties. Forty-two percent (50 of 118) of the respondents perceived the presence of AR in worms, including pinworms (16%), strongylins (15%), species of Draschia and Habronema (6%), Strongyloides westeri (2%) and tapeworms (1%). Twenty-seven percent (32 of 118) of the respondents rarely discussed equine worm control practices with their clients. This study provides insights into the perception and worm control practices recommended by Australian veterinarians to manage equine parasites. The findings highlight the importance of continued education and awareness of AR, and the use of non-chemical methods as well as consideration of the legislation of prescription-only use of anthelmintics based on FECs to achieve sustainable control of GINs in Australian horses

Pravastatin for early-onset pre-eclampsia:a randomised, blinded, placebo-controlled trial

Objective: Women with pre-eclampsia have elevated circulating levels of soluble fms-like tyrosine kinase-1 (sFlt-1). Statins can reduce sFlt-1 from cultured cells and improve pregnancy outcome in animals with a pre-eclampsia-like syndrome. We investigated the effect of pravastatin on plasma sFlt-1 levels during pre-eclampsia. Design: Blinded (clinician and participant), proof of principle, placebo-controlled trial. Setting: Fifteen UK maternity units. Population: We used a minimisation algorithm to assign 62 women with early-onset pre-eclampsia (24 +0–31 +6 weeks of gestation) to receive pravastatin 40 mg daily (n = 30) or matched placebo (n = 32), from randomisation to childbirth. Primary outcome: Difference in mean plasma sFlt-1 levels over the first 3 days following randomisation. Results: The difference in the mean maternal plasma sFlt-1 levels over the first 3 days after randomisation between the pravastatin (n = 27) and placebo (n = 29) groups was 292 pg/ml (95% CI −1175 to 592; P = 0.5), and over days 1–14 was 48 pg/ml (95% CI −1009 to 913; P = 0.9). Women who received pravastatin had a similar length of pregnancy following randomisation compared with those who received placebo (hazard ratio 0.84; 95% CI 0.50–1.40; P = 0.6). The median time from randomisation to childbirth was 9 days [interquartile range (IQR) 5–14 days] for the pravastatin group and 7 days (IQR 4–11 days) for the placebo group. There were three perinatal deaths in the placebo-treated group and no deaths or serious adverse events attributable to pravastatin. Conclusions: We found no evidence that pravastatin lowered maternal plasma sFlt-1 levels once early-onset pre-eclampsia had developed. Pravastatin appears to have no adverse perinatal effects. Tweetable abstract: Pravastatin does not improve maternal plasma sFlt-1 or placental growth factor levels following a diagnosis of early preterm pre-eclampsia #clinicaltrial finds

Anti-inflammatory effects of clenbuterol hydrochloride on leukocyte activation in the horse

© 2013 Lucy Anne CudmoreThe work reported in this thesis aimed to investigate the potential anti-inflammatory effects of clenbuterol hydrochloride in the treatment of equine endotoxaemia. Beta adrenergic agonists, such as clenbuterol hydrochloride reduce leukocyte activation and cytokine production through the up regulation of cyclic adenosine monophosphate. Investigations measured pro-inflammatory cytokine production (IL-1β and TNFα) by equine leukocytes, following stimulation with endotoxin, peptidoglycan and lipoteichoic acid and treatment with clenbuterol hydrochloride during in vitro and in vivo studies. The study also aimed to develop a model enabling correlation of pharmacokinetic and pharmacodynamic drug properties in order to predict an optimum dosing regimen for novel anti-inflammatory agents. The results of the study indicated that clenbuterol hydrochloride has significant anti-inflammatory effects on equine leukocytes challenged with Gram negative and Gram positive bacterial toxins in in vitro assays. Clenbuterol hydrochloride was most potent at inhibiting TNFα production in response to endotoxin, with the effects on peptidoglycan and lipoteichoic acid only being significantly inhibited at much higher clenbuterol hydrochloride concentrations (>10-6 M). Also a marked reduction in lipopolysaccharide stimulated IL-1β cytokine production following treatment with clenbuterol hydrochloride was recognised. In in vivo models of equine endotoxaemia, pre-treatment with oral clenbuterol hydrochloride caused a significant reduction in the peak rectal temperature and peak plasma TNFα concentrations. A model correlating clenbuterol hydrochloride pharmacodynamics and pharmacokinetics was developed. Clenbuterol may have a beneficial role alongside non-steroidal anti-inflammatory drugs and other previously investigated therapies in the treatment of inflammation associated with sepsis in horses. Further investigations in clinical cases of equine endotoxaemia are essential prior to the recommendation of clenbuterol hydrochloride as an adjuvant anti-inflammatory agent in the treatment of systemic inflammation

Peritoneal fluid analysis in equine post‐partum emergencies admitted to a referral hospital: a retrospective study of 110 cases

Background: Peritoneal fluid analysis has both diagnostic and prognostic value in colic but is little reported in the post-partum mare. Multiple conditions may present similarly in this period, and peritoneal fluid findings may aid a prompt diagnosis. Objectives: To describe the peritoneal fluid findings and their association with diagnosis in mares presenting to a single referral hospital for treatment of post-partum emergencies. Study design: A retrospective clinical study. Methods: Clinical records of 110 Thoroughbred mares were reviewed. Details of peritoneal fluid analysis from samples obtained at admission were recorded, in addition to history, physical examination, presenting clinicopathological data. Cases were classified by their primary diagnosis into groups of gastrointestinal tract (GIT), urogenital trauma (UGT) and post parturient haemorrhage (PPH). Univariable analysis was performed to compare findings between groups, using one-way ANOVA and post hoc Tukey/Kruskal-Wallis, as appropriate. A multinomial logistic regression was performed for variables significant in the univariable analysis. Results: When separated into their diagnostic categories, 33/110 (30%) mares were classified as GIT, 55/110 (50%) UGT and 22/110 (20%) PPH. Peritoneal fluid packed cell volume (PCV), nucleated cell count (WBCC) and cytological findings were significantly different between diagnostic categories. The likelihood of diagnosis of PPH increased with an increase in peritoneal fluid PCV, the absence of degenerate neutrophils on peritoneal fluid cytology and a decrease in the peritoneal fluid WBCC. Overall survival to discharge was 55%. Main limitations: The study is referral hospital-based and retrospective in nature. Missing data reduced the power of analysis for several variables. Conclusions: Peritoneal fluid analysis may guide diagnosis in post-partum emergencies, but no one factor is uniformly diagnostic. Mares with PPH presented with a non-septic peritonitis with higher peritoneal PCV

Systematic review of gastrointestinal nematodes of horses from Australia

Background: Equine gastrointestinal nematodes (GINs) have been the subject of intermittent studies in Australia over the past few decades. However, comprehensive information on the epidemiology of equine GINs, the efficacy of available anthelmintic drugs and the prevalence of anthelmintic resistance (AR) in Australasia is lacking. Herein, we have systematically reviewed existing knowledge on the horse GINs recorded in Australia, and main aspects of their pathogeneses, epidemiology, diagnoses, treatment and control. Methods: Six electronic databases were searched for publications on GINs of Australian horses that met our inclusion criteria for the systematic review. Subsets of publications were subjected to review epidemiology, diagnoses, pathogeneses, treatment and control of GINs of horses from Australia. Results: A total of 51 articles published between 1950 to 2018 were included. The main GINs reported in Australian horses were cyathostomins (at least 28 species), Draschia megastoma, Habronema muscae, H. majus, Oxyuris equi, Parascaris equorum, Strongyloides westeri and Trichostrongylus axei across different climatic regions of Queensland, New South Wales, Victoria, and Western Australia. Nematodes are diagnosed based on the traditional McMaster egg counting technique, though molecular markers to characterise common GINs of equines were characterised in 1990s. The use of anthelmintic drugs remains the most widely-used strategy for controlling equine GIN parasites in Australia; however, the threshold of faecal egg count that should trigger treatment in horses, remains controversial. Furthermore, anthelmintic resistance within GIN population of horses is becoming a common problem in Australia. Conclusions: Although GINs infecting Australian horses have been the subject of occasional studies over the past few decades, the effective control of GIN infections is hampered by a generalised lack of knowledge in various disciplines of equine parasitology. Therefore, coordinated and focused research is required to fill our knowledge gaps in these areas to maximise equine health and minimise economic losses associated with the parasitic infections in Australia

Egg reappearance periods of anthelmintics against equine cyathostomins: The state of play revisited

Cyathostomins are the most common and highly prevalent parasites of horses worldwide. Historically, the control of cyathostomins has mainly relied on the routine use of anthelmintic products. Increasing reports on anthelmintic resistance (AR) in cyathostomins are concerning. A potential method proposed for detecting emerging AR in cyathostomins has been estimating the egg reappearance period (ERP). This paper reviews the data available for the ERP of cyathostomins against the three major classes of anthelmintics, macrocyclic lactones, tetrahydropyrimidines, and benzimidazoles. Published peer-reviewed original research articles were obtained from three databases (PubMed, CAB Direct and Web of Science) and were evaluated for their inclusion in a systematic review. Subsets of articles were then subjected to a review of ERP data. A total of 54 (of 134) studies published between 1972 and 2022 met the criteria for inclusion in the systematic review. Until the beginning of 2022, there was no agreed definition of the ERP; eight definitions of ERP were identified in the literature, complicating the comparison between studies. Additionally, potential risk factors for the shortening of the ERP, including previous anthelmintic use and climate, were frequently not described. Reports of shortened ERP for moxidectin and ivermectin are frequent: 20 studies that used comparable ERP definitions reported shortened moxidectin and ivermectin ERPs of 35 and 28 days, respectively. It is unclear whether the ERPs of these anthelmintics reduced to such levels are due to the development of AR or some biological factors related to horses, cyathostomin species, and/or the environment. The ERPs for other anthelmintics, such as fenbendazole and pyrantel, were frequently not reported due to established resistance against these drugs. Future research in horses is required to understand the mechanism(s) behind the shortening of ERP for cyathostomins. Based on this systematic review, we propose recommendations for future ERP studies

Complications of Subspecialty Ophthalmic Care: Systemic Complications from the Intravitreal Administration of Agents that Target the Vascular Endothelial Growth Factor Pathway

The treatment of neovascular age-related macular degeneration (AMD) and other pathologic ocular conditions that overexpress the vascular endothelial growth factor (VEGF) has been revolutionized in the last decade by the introduction of intravitreal agents that target the VEGF pathway. Since treatment trials are designed primarily to assess the prevention of vision loss caused by ocular conditions, they are inadequate for detecting rare, but potentially serious, systemic side effects. The aim of this article is to present what the ophthalmologist needs to know about systemic complications from anti-VEGF therapy and review the likelihood that these side effects occur in the context of small, but often-repeated, intravitreal doses of these potent biological medications. Preferred practice patterns need to be developed that weigh the ability of these medications to mitigate potentially blinding conditions, while at the same time minimizing the risk of adverse outcomes in specific patient populations that possess multiple and often interrelated medical comorbidities