Evaluation of a combination of Citrus aurantium var. Dulcis essential oil and albendazole for the treatment of sheep gastrointestinal nematodes.

Citrus fruits are consumed all over the world and their by-products are used for animal feed and essential oils production. This study aimed to evaluate the in vitro and in vivo activity of Citrus aurantium var. Dulcis essential oil (CaEO) combined with ABZ against benzimidazole resistant Haemonchus contortus. In vitro egg hatching assays (EHA) were performed using CaEO and ABZ to estimate the effective concentration to achieve 50% egg death (EC50) values and calculate the test essential oil and drug combinations using a simplex-centroid mixture design. These concentrations were used for a second round of EHAs. Sixteen sheep were randomly allocated into two groups and treated with ABZ and the combination of CaEO and ABZ, and faecal egg count reduction tests were performed. In the first round of EHA, CaEO and ABZ showed EC50 values of 0.57 and 0.0048 mg mL-1, respectively. The H. contortus strain used in the study was shown to be highly benzimidazole resistant, with only 1.5% of parasites having susceptible ß-tubulin SNP genotypes. The ABZ reduced the shedding of nematode eggs by 78%, however, its combination with CaEO reduced faecal egg counts by only 9%. The present study is important to highlight the interferences of natural products in anthelmintic metabolism and consequently in drug efficacy.

The Prevalence and Control of Lungworms of Pastoral Ruminants in Iran.

Lungworms of the genera Dictyocaulus, Muellerius, Protostrongylus, and Cystocaulus are common helminths of domestic and wild ruminants with substantial veterinary and economic importance. Several studies have assessed the presence and prevalence of lungworm infections in ruminants in Iran. This report compiles the available scientific information about the occurrence of lungworms in domestic and wild ruminants in Iran between 1931 and June 2022 to give an insight into their epidemiology, and where possible to describe drug treatment efficacy. For this purpose, national and international scientific databases were searched. Overall, 54 publications comprising 33 articles in peer-reviewed journals, 8 conference papers, and 13 dissertations were evaluated regarding prevalence data; and an additional 4 peer-reviewed articles were evaluated regarding drug efficacy. Seven species of lungworms, namely Dictyocaulus filaria, Dictyocaulus viviparus, Dictyocaulus eckerti, Protostrongylus rufescens, Protostrongylus raillietti, Muellerius capillaris, and Cystocaulus ocreatus have been recorded from different ruminant hosts in Iran. Thirty-three studies conducted on small ruminant (sheep and goat) lungworms reported prevalences of lungworm infection of 11.6%, 45.81% and 66.29% using abattoir meat inspection, Baermann technique and fecal flotation, respectively. Eight studies conducted on large ruminants (cattle and water buffalo) reported prevalences of infection of 14.83%, 13.98% and 5% using abattoir meat inspection, the Baermann technique and fecal flotation, respectively. The prevalence of infection in wild ruminants was variable across examined species; 38% in urial, 37% in wild goats, 5% in goitered gazelles and 67% in red deer, in addition to a single case report in roe deer. There are few contemporary studies assessing the efficacy of currently available broad-spectrum anthelmintic compounds against lungworms in Iran. The high prevalence of multiple lungworm species in Iran, combined with a lack of information about drug efficacy, supports the need to improve the understanding of these important nematode parasites and inform the development of sustainable control strategies. The aim of this review and meta-analysis is to provide a baseline for future conventional parasitology and next generation molecular epidemiological studies of lungworm infection in pastoral ruminants in Iran.

Practices employed by veterinary practitioners for controlling canine gastrointestinal helminths and ectoparasites / Práticas realizadas por veterinários para controle de helmintos gastrintestinais e ectoparasitos de cães

Abstract The present study attempted to evaluate the practical experience and methods employed by Brazilian veterinary practitioners for control of parasites. Twenty-one questions were asked of 403 veterinary practitioners based in different climatic zones with reference to parasite epidemiology from the country. Administration of a combination of drugs at three-month intervals was the most common regime recommended for prophylaxis against gastrointestinal helminths, with a single treatment repeated after 15 days. Routine prophylaxis against dog ectoparasites was recommended by 82.4% veterinary practitioners, and 46.6% changed the drug compound used. Monthly prophylaxic treatments for ectoparasites, using systemic, topical and/or collar-impregnated drugs, was recommended by 21.5% veterinary practitioners. Side-effects of ectoparasiticide-impregnated collars were suspected by 58% of the veterinary practitioners. Isoxazolines were the most frequently used chemical group to treat ectoparasites in dogs. Poor efficacy of fipronil in controlling ticks was suspected by 79.5% of the veterinary practitioners. The isoxazolines and combination of anthelmintic compounds are the most common drugs to prevent or treat ectoparasites and gastrointestinal nematodes, respectively. The suspect of the inefficacy of antiparasitic drugs is shared among the veterinary practitioners from part of Brazil. Guidelines are needed, specifically for the control of gastrointestinal helminths and ectoparasites in Brazilian dogs.

Resumo O presente estudo avaliou os métodos de controle empregados por médicos veterinários clínicos para o controle de parasitos de cães no Brasil. Vinte e uma perguntas foram feitas a 403 veterinários de diferentes regiões do país. O uso de associações de compostos ativos em intervalos de três meses foi o mais recomendado para profilaxia de helmintos gastrointestinais, repetido após 15 dias. A profilaxia de rotina contra ectoparasitos foi recomendada por 82,4% dos veterinários, e 46,6% mudam rotineiramente o composto indicado. Tratamentos profiláticos mensais para ectoparasitos, com produtos sistêmicos, tópicos e / ou impregnados com colar, foram recomendados por 21,5% dos veterinários. Os efeitos colaterais das coleiras impregnadas com ectoparasiticidas foram relatados por 58% dos médicos veterinários. As isoxazolinas foram o grupo químico mais utilizado para tratar ectoparasitos em cães. A baixa eficácia do fipronil no controle de carrapatos foi suspeitada por 79,5% dos médicos veterinários. As isoxazolinas e a associação de compostos anti-helmínticos são os medicamentos mais comuns para prevenir ou tratar ectoparasitos e nematoides gastrointestinais, respectivamente. A suspeita da ineficácia dos antiparasitários é compartilhada entre os médicos veterinários de algumas regiões do Brasil. Orientações são necessárias, especificamente para o controle de helmintos e ectoparasitos gastrointestinais em cães no Brasil.

A Genome Resequencing-Based Genetic Map Reveals the Recombination Landscape of an Outbred Parasitic Nematode in the Presence of Polyploidy and Polyandry.

The parasitic nematode Haemonchus contortus is an economically and clinically important pathogen of small ruminants, and a model system for understanding the mechanisms and evolution of traits such as anthelmintic resistance. Anthelmintic resistance is widespread and is a major threat to the sustainability of livestock agriculture globally; however, little is known about the genome architecture and parameters such as recombination that will ultimately influence the rate at which resistance may evolve and spread. Here, we performed a genetic cross between two divergent strains of H. contortus, and subsequently used whole-genome resequencing of a female worm and her brood to identify the distribution of genome-wide variation that characterizes these strains. Using a novel bioinformatic approach to identify variants that segregate as expected in a pseudotestcross, we characterized linkage groups and estimated genetic distances between markers to generate a chromosome-scale F1 genetic map. We exploited this map to reveal the recombination landscape, the first for any helminth species, demonstrating extensive variation in recombination rate within and between chromosomes. Analyses of these data also revealed the extent of polyandry, whereby at least eight males were found to have contributed to the genetic variation of the progeny analyzed. Triploid offspring were also identified, which we hypothesize are the result of nondisjunction during female meiosis or polyspermy. These results expand our knowledge of the genetics of parasitic helminths and the unusual life-history of H. contortus, and enhance ongoing efforts to understand the genetic basis of resistance to the drugs used to control these worms and for related species that infect livestock and humans throughout the world. This study also demonstrates the feasibility of using whole-genome resequencing data to directly construct a genetic map in a single generation cross from a noninbred nonmodel organism with a complex lifecycle.

Relationship between thoracic auscultation and lung pathology detected by ultrasonography in sheep.

The utility of routine auscultation to detect and characterise the nature of a range of superficial lung and pleural pathologies in domestic sheep was assessed using ultrasonographic examination to indicate and localise pathologies pre-mortem. Necropsy examination was then used to fully characterise the nature and extent of the lesions. Auscultation recordings were made from 10 normal sheep with no clinical evidence of respiratory disease and with absence of significant superficial lung pathology, which was confirmed initially by ultrasound examination and subsequently at necropsy examination. A further two sheep with endotoxaemia and 30 sheep with well-defined lung lesions were also examined. Increased audibility of normal lung sounds in 4/10 normal sheep was associated with tachypnoea as a consequence of handling and transport during hot weather and was also observed in the two sheep with endotoxaemia. Moderate to severe coarse crackles detected in all advanced cases of ovine pulmonary adenocarcinoma (n=16) were audible over an area larger than the lesion distribution identified during ultrasound examination, and confirmed later at necropsy. Auscultation did not detect abnormal sounds in any of the five sheep with focal pleural abscesses (up to 10 cm diameter). Unilateral pyothorax caused attenuation of sounds relative to the contra-lateral normal lung in all three sheep with this condition. Marked fibrinous pleurisy caused attenuation of sounds relative to normal areas of lung in six sheep. No sounds resembling the description of pleural frictions rubs were heard in the sheep with marked fibrinous pleurisy (n=6) or associated with focal pleural abscesses (n=5). Routine interpretation of auscultated sound did not allow the presence of superficial lung pathology or its distribution to be accurately defined in the respiratory diseases represented in this study.

Compressive cervical myelopathy in young Texel and Beltex sheep.

BACKGROUND: This investigation was prompted by the referral of increasing numbers of young Texel and Beltex rams with ataxia and weakness, or wobbler syndrome. HYPOTHESIS: The study aims were to describe the clinical and pathologic findings in affected sheep. ANIMALS: The animals evaluated in this study included 7 Texel sheep (6 male and 1 female) and 3 Beltex sheep (2 male and 1 female) referred from pedigree flocks. Typically, the sheep were 15-18 months of age at referral. METHODS: Diagnostic investigations included radiographic and computed tomographic (CT) myelography followed by gross postmortem and histopathologic examinations. RESULTS: Clinical findings typical of cervical spinal cord compression were present in all sheep but varied in severity. Myelography confirmed dorsal spinal cord compression in the region of C6-C7. No bony abnormalities were identified as described in cases of canine and equine wobbler syndrome. Postmortem examinations revealed discrete, smooth, nodular to polypoid projections of adipose tissue apparently prolapsing through the dorsolateral intervertebral space at C6-C7 and causing localized spinal cord compression. Histopathology of the nodules confirmed that they were composed of well-differentiated adipocytes typical of fatty tissue. Spinal cord lesions were similar in all sheep with marked Wallerian degeneration at the site of compression and mild Wallerian degeneration present cranial and caudal to the lesion. CONCLUSIONS AND CLINICAL IMPORTANCE: The findings of this study suggest a novel cervical myelopathy in these sheep breeds caused by the presence of fatty nodules encroaching into the dorsal vertebral canal at C6-C7. Additional investigations are required to establish the etiology and possible hereditary risk factors for this unique clinicopathologic syndrome.