Strongylida

A sensitive and specific PCR hybridization assay was applied for species-specific monitoring of the small strongyle (Strongylida: Cyathostominae) populations in horses in a herd before and after treatment with the anthelmintic drug ivermectin. Fecal samples were collected pre- and post-treatment weekly from eight individual horses (four foals and four yearlings) for 6 weeks to determine counts of strongyle eggs per gram of feces (EPGs). Additionally, one foal and one yearling were nontreated controls. Also, one horse, from another herd known to be infected with Strongylus spp., was a positive control for these parasites. Genomic DNA was obtained from eggs in groups of approximately 6000-7000 eggs except for two samples containing low EPGs in which 450 eggs were used. Amplification of the intergenic spacers (IGSs) of ribosomal DNA (rDNA) of small and large strongyles followed by reverse line blot (RLB) assay were performed to identify the presence of the 12 most common equine small s...

Ixodid ticks were collected from scrub hares (Lepus saxatilis) at three localities. Nine tick species were recovered from 24 hares examined at Pafuri, Kruger National Park, Northern Transvaal. The most abundant and prevalent species were Hyalomma truncatum, Rhipicephalus kochi and a Rhipicephalus species (near R. pravus). Twelve tick species were collected from 120 scrub hares examined around Skukuza, Kruger National Park, Eastern Transvaal. The immature stages of Hyalomma truncatum were most abundant and those of Amblyomma hebraeum most prevalent on the hares. No haematozoa were found on blood smears made from these hares. Thirty-four scrub hares on mixed cattle and game farms near Hluhluwe, north-eastern KwaZulu-Natal harboured 12 tick species. The most abundant and prevalent of these were the immature stages of Rhipicephalus muehlensi. Piroplasms, tentatively identified as Babesia leporis, were present on blood smears of eight of these hares. The host status of scrub hares for 18...

Fecal analyses are becoming increasingly important for equine establishments as a means of parasite surveillance and detection of anthelmintic resistance. Although several studies have evaluated various egg counting techniques, little is known about the quantitative effects of pre-analytic factors such as collection and storage of fecal samples. This study evaluated the effects of storage temperature, storage time and airtight versus open-air storage on fecal egg counts. The experimental protocols were replicated in two study locations: Copenhagen, Denmark and Athens, Georgia, USA. In both locations, the experiment was repeated three times, and five repeated egg counts were performed at each time point of analysis. In experiment A, feces were collected rectally and stored airtight at freezer (−10 to −18 °C), refrigerator (4 °C), room (18–24 °C), or incubator (37–38 °C) temperatures. Egg counts were performed after 0, 6, 12, 24, 48, and 120 h of storage. In experiment B, feces were collected rectally and stored airtight or in the open air in the horse barn for up to 24 h. Egg counts were performed after 0, 3, 6, 12, and 24 h of storage. In experiment A at both locations, samples kept in the refrigerator showed no decline in egg counts, whereas storage in the freezer and incubator led to significantly declining egg numbers during the study. In contrast, storage at room temperature yielded marked differences between the two study locations: egg counts remained stable in the U.S. study, whereas the Danish study revealed a significant decline after 24 h. In experiment B, the Danish study showed no differences between airtight and open-air storage and no changes over time, while the U.S. study found a significant decline for open-air storage after 12 h. This difference was attributed to the different barn temperatures in the two studies. To our knowledge, this is the first study to evaluate the pre-analytic factors affecting egg counts in horses using an experimental protocol replicated in two contrasting geographic and climatic locations. Our results demonstrate that refrigeration is the best method for storage of fecal samples intended for egg count analysis, but that accurate results can be derived from fecal samples collected from the ground within 12 h of passage.

Global climate change is altering the ecology of infectious agents and driving the emergence of disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate

Tracer tests conducted over a 3-year period were aimed at measuring the level and species nematode composition of survival on pastures with a special focus on winter months. The survival of infective larvae in chilly conditions is not significantly affected by Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus and Chabertia ovina. On the contrary, the number of Teladorsagia circumcincta and Nematodirus filicollis significantly increased in milder winter conditions. The results confirmed an epidemiological strategy of overwintering in the arrested stage for Teladorsagia circumcincta and Nematodirus filicollis; the epidemiological strategy of genus Trichostrongylus used both strategies—in particular the tolerance of free-living stages to cold conditions. Part of the population overwintered in the arrested stage as well.

1. Seasonality of rainfall can exert a strong influence on animal condition and on host-parasite interactions. The body condition of ruminants fluctuates seasonally in response to changes in energy requirements, foraging patterns and resource availability, and seasonal variation in parasite infections may further alter ruminant body condition. 2. This study disentangles the effects of rainfall and gastrointestinal parasite infections on springbok (Antidorcas marsupialis) body condition and determines how these factors vary among demographic groups. 3. Using data from four years and three study areas, we investigated (i) the influence of rainfall variation, demographic factors and parasite interactions on parasite prevalence or infection intensity, (ii) whether parasitism or rainfall is a more important predictor of springbok body condition and (iii) how parasitism and condition vary among study areas along a rainfall gradient. 4. We found that increased parasite intensity is associated with reduced body condition only for adult females. For all other demographic groups, body condition was significantly related to prior rainfall and not to parasitism. Rainfall lagged by two months had a positive effect on body condition. 5. Adult females showed evidence of a 'periparturient rise' in parasite intensity and had higher parasite intensity and lower body condition than adult males after parturition and during early lactation. After juveniles were weaned, adult females had lower parasite intensity than adult males. Sex differences in parasitism and condition may be due to differences between adult females and males in the seasonal timing of reproductive effort and its effects on host immunity, as well as documented sex differences in vulnerability to predation. 6. Our results highlight that parasites and the environment can synergistically affect host populations, but that these interactions might be masked by their interwoven relationships, their differential impacts on demographic groups, and the different time-scales at which they operate.

Forty-eight tracer lambs were killed in 2004–2007. The abomasum, duodenum, small intestine (jejunum and ileum), colon and caecum were collected and processed for parasites enumeration and identification—mucosal scrapings of both abomasums and intestines were digested. Out of 48 gastrointestinal tracts examined, all were found to be positive for nematode infection. Seventeen species of gastrointestinal nematodes were recovered: Bunostomum trigonocephalum, Cooperia curticei, Haemonchus contortus, Chabertia ovina, Nematodirus battus, Nematodirus filicollis, Oesophagostomum venulosum, Teladorsagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Strongyloides papillosus, Trichuris ovis, Trichuris globulosa, Trichuris skrjabini and Skrjabinema ovis. All species were searched for in the entire gastrointestinal tract. Six species of nematodes were recovered from abnormal sites, naturally in small numbers of lambs as well as in small amounts: Nematodirus battus in the abomasums (6.67% of lambs), N. filicollis in the caecum and in the colon (%4 and 8%, respectively), T. axei in the colon (9.52%), T. colubriformis in the colon (13.89%), T. vitrinus in the caecum (16.67%), in the colon (20.00%) and in the abomasum (3.33%). T. ovis was found in one case in the small intestine.

The study of immunity to helminth infection has been central to understanding the function of type 2 cytokines and their targets. Although type 2 cytokines are considered anti-inflammatory and promote tissue repair, they also contribute to allergy and fibrosis. Here, we utilise data from helminth infection models, to illustrate that IL-17 and neutrophils, typically associated with pro-inflammatory responses, are intimately linked with type 2 immunity. Neutrophils work with IL-4Rα-activated macrophages to control incoming larvae but this comes at a cost of enhanced tissue damage. Chitinase like proteins (CLPs) bridge these diverse outcomes, inducing both protective IL-17 and reparative Th2 responses. Dysregulation of CLPs, IL-17 and neutrophils likely contribute to disease severity and pathology associated with type 2 immunity.