Diversity and burden of helminthiasis in wild ruminants in Iran

Epidemiology and diversity of gastrointestinal tract helminths of wild ruminants in sub-Saharan Africa: a review

This review summarises studies on distribution, diversity, and prevalence of gastrointestinal helminth infections in wild ruminants in sub-Saharan Africa. The results showed that 109 gastrointestinal tract (GIT) helminth species or species complexes were recorded in 10 sub-Saharan African countries. South Africa reported the highest number of species because most studies were carried out in this country. Eighty-eight nematode species or species complexes were recorded from 30 wild ruminant species across eight countries. The genus Trichostrongylus recorded the highest number of species and utilised the highest number of wild ruminant species, and along with Haemonchus spp., was the most widely distributed geographically. Fifteen trematode species or species complexes were reported from seven countries. The genus Paramphistomum recorded the highest number of species, and Calicophoron calicophoron was the most commonly occurring species in sub-Saharan African countries and infected the highest number of hosts. Six cestode species or species complexes from one family were documented from 14 wild hosts in seven countries. Moniezia spp. were the most commonly distributed in terms of host range and geographically. Impala were infected by the highest number of nematodes, whilst Nyala were infected by the highest number of trematode species. Greater kudu and Impala harbored the largest number of cestodes. The prevalence amongst the three GIT helminths taxa ranged between 1.4% and 100% for nematodes, 0.8% and 100% for trematodes, and 1.4% and 50% for cestodes. There is still limited information on the distribution and diversity of GIT helminths in wild ruminants in most sub-Saharan African countries.

Helminths of captive and free-ranging populations of the mountain gazelle (Gazella gazella): Evidence from faecal examination

BACKGROUND

Understanding parasite diversity in wild and captive animal populations has critical implications for both individual animal health and ecosystem dynamics in a broader sense. In mountain gazelles (Gazella gazella), the gastrointestinal helminth community is poorly understood, limiting our efforts in the conservation of this endangered bovid species. This species has only two remaining populations in the world, including the isolated northernmost population in Türkiye.

OBJECTIVES

To identify and compare the diversity and prevalence of gastrointestinal helminths in captive and free-ranging populations of mountain gazelles in Hatay, Türkiye, and to assess potential zoonotic risks.

METHODS

In total, 105 fresh faecal samples, 45 individual samples and 60 faecal samples, representing 16 pools, from both captive and free-ranging populations were collected and analysed using Fulleborn flotation, Benedek sedimentation and Bearman-Wetzel methods faecal flotation methods, including the McMaster technique to determine the severity of infection.

RESULTS

We detected 12 helminth taxa in our examination of faecal samples, including gastrointestinal nematodes, lungworms and trematodes. Parasites from the Trichostrongyloidea family demonstrated variable hatching stages and rates, potentially influenced by ambient conditions. We also detected one protozoan among the samples. Our results revealed a higher diversity of parasites in free-ranging populations compared to captive ones.

CONCLUSIONS

This study underscores the necessity for regular parasitological surveillance in both captive and free-ranging wildlife populations for effective conservation management. It also contributes to the 'One Health' perspective by highlighting the potential zoonotic risks posed by parasites in wild ruminants. Our results have implications for the conservation and management of the mountain gazelle.

Parasites Detected in Hatay Mountain Gazelles (Gazella gazella)

The current study aimed to detect parasites in Hatay Mountain Gazelles (Gazella gazella), which are categorized as endangered according to the International Union for Conservation of Nature. The present study was conducted in Hatay Mountain Gazelle Wildlife Development Area, where 40 gazelles inhabited (30 ♀, 10 ♂), 15 of which were over three years old as well-considered adults. Fecal samples were taken from 60 fecal foci immediately after the defecation of the gazelles. Each of the fecal samples was analysed with Benedek sedimentation, Fülleborn flotation and Bearman-Wetzel methods and examined under a light microscope. In addition, Ixodid ticks were collected from an injured gazelle which was brought to Hatay Mustafa Kemal University, Wildlife Rescue and Rehabilitation Center, then were identified under the stereomicroscope. Nematodirus spp. (5/60, 8%), Marshallagia spp. (4/60, 7%), Trichostrongylus spp. (3/60, 5%) eggs, Dictiyocaulus filaria larvae (3/60, 5%) and Eimeria spp. oocysts (9/60, 15%) were determined based on the microscopic examination. Ixodid tick samples were identified as Rhipicephalus turanicus (2 ♀, 3 ♂). Thus this is the first report of the existence of parasites in Hatay Mountain Gazelles in Turkey. It is thought that skin and fecal examinations should be performed to prevent parasitic diseases in gazelles.

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.

Excretory-secretory products from the brown stomach worm, Teladorsagia circumcincta, exert antimicrobial activity in in vitro growth assays

BACKGROUND

Over the past decade, evidence has emerged of the ability of gastrointestinal (GI) helminth parasites to alter the composition of the host gut microbiome; however, the mechanism(s) underpinning such interactions remain unclear. In the current study, we (i) undertake proteomic analyses of the excretory-secretory products (ESPs), including secreted extracellular vesicles (EVs), of the 'brown stomach worm' Teladorsagia circumcincta, one of the major agents causing parasite gastroenteritis in temperate areas worldwide; (ii) conduct bioinformatic analyses to identify and characterise antimicrobial peptides (AMPs) with putative antimicrobial activity; and (iii) assess the bactericidal and/or bacteriostatic properties of T. circumcincta EVs, and whole and EV-depleted ESPs, using bacterial growth inhibition assays.

METHODS

Size-exclusion chromatography was applied to the isolation of EVs from whole T. circumcincta ESPs, followed by EV characterisation via nanoparticle tracking analysis and transmission electron microscopy. Proteomic analysis of EVs and EV-depleted ESPs was conducted using liquid chromatography-tandem mass spectrometry, and prediction of putative AMPs was performed using available online tools. The antimicrobial activities of T. circumcincta EVs and of whole and EV-depleted ESPs against Escherichia coli were evaluated using bacterial growth inhibition assays.

RESULTS

Several molecules with putative antimicrobial activity were identified in both EVs and EV-depleted ESPs from adult T. circumcincta. Whilst exposure of E. coli to whole ESPs resulted in a significant reduction of colony-forming units over 3 h, bacterial growth was not reduced following exposure to worm EVs or EV-depleted ESPs.

CONCLUSIONS

Our data points towards a bactericidal and/or bacteriostatic function of T. circumcincta ESPs, likely mediated by molecules with antimicrobial activity.