Systemic Immune Modulation by Gastrointestinal Nematodes

Following stimulation of the immune system, tissue trauma, or exposure to some stressors, there can be activation of the acute phase response (APR). This is a primitive defence reaction that helps protect the host against noxious insults. Part of the response involvess a change in priorities for nutrient utilisation, when the pro-inflammatory cytokines IL-1α/β, TNFα, IL-6 and IFNα/β override the normal hypothalamic-somatotropic control of nutrient utilisation. The pro-inflammatory cytokines reduce protein synthesis and increase protein catabolism in muscle, induce synthesis of acute phase proteins in liver, and decrease de novo fatty acid synthesis and increase lipolysis in adipose tissue. In the central nervous system there is induction of fever, which increases metabolic rate, and induction of sickness behaviour. There are few reports in the literature of studies on the APR during gastrointestinal nematode (GIN) infection in sheep. However, IL-6 message is present in mucosa during Trichostrongylus colubriformis infection and mast cells in many species contain preformed TNFα. The changes in appetite, growth and nitrogen metabolism seen during GIN parasitism in sheep are in accord with the systemic effects of the APR. This review reports studies on activation of the APR in mastitis and fly strike, and the effects of APR on wool growth in high and low tensile strength genotypes and during Haemonchus contortus infection. The modified capacity of tissues to take up amino acids during pro-inflammatory cytokine perturbation of nutrient utilisation may limit the capacity for dietary supplementation to remedy the cost of host defence. Genetic variation may occur in production of pro-inflammatory cytokines or in tissue sensitivity to pro-inflammatory cytokines during GIN infection and may provide a basis for selection for resilience. Some questions for future research are identified.

The complexities of multi-use landscapes require sophisticated approaches to addressing disease transmission risks. We explored gastro-intestinal nematode (GINs) infections in the North India Trans-Himalayas through a socio-ecological lens, integrating parasite transmission modelling with field surveys and local knowledge, and evaluated the likely effectiveness of potential interventions. Bharal (blue sheep; Pseudois nayaur), a native wild herbivore, and livestock share pasture year-round and livestock commonly show signs of GINs infection. While both wild and domestic ungulates had GINs infections, egg counts indicated significantly higher parasite burdens in bharal than livestock. However, due to higher livestock densities, they contributed more to the total count of eggs and infective larvae on pasture. Herders also reported health issues in their sheep and goats consistent with parasite infections. Model simulations suggested that pasture infectivity in this system is governed by historical pasture use and gradually accumulated larval development during the summer, with no distinct short-term flashpoints for transmission. The most effective intervention was consequently predicted to be early-season parasite suppression in livestock using temperature in spring as a cue. A 1-month pause in egg output from livestock could lead to a reduction in total annual availability of infective larvae on pasture of 76%, potentially benefitting the health of both livestock and bharal. Modelling suggested that climate change over the past 33 years has led to no overall change in GINs transmission potential, but an increase in the relative influence of temperature over precipitation in driving pasture infectivity. Our study provides a transferable multi-pronged approach to investigating disease transmission, in order to support herders' livelihoods and conserve wild ungulates.

It is important to determine whether gastrointestinal nematodes (GINs) affect foliage choice of goats leading to confirm the expression of a self-medication behavior. This study investigated the effect of GIN infection on tropical foliage selection by goats. During experimental stage 1 (10days), goats had a natural mixed GIN infection, and at stage 2 (10days), goats were treated with effective anthelmintics to maintain them free of GIN infection. During stage 1 the twelve adult goats (32 ± 2.3kg live weight [LW]) were assigned to three groups (n = 4) according to their initial GIN infection status: HI group, with fecal egg count (FEC) between 1450 and 2150 eggs per g/feces (EPG); MI group, medium FEC (592-1167 EPG); and the NI group, free from GIN infection. Fresh foliage of four tropical plants were offered to goats ad libitum for 1h daily: Gymnopodium floribundum (high condensed tannin [CT] content, 37-40%), Mimosa bahamensis (medium CT content, 16-17%), Leucaena leucocephala (low CT content, 3-5%), and Viguiera dentata (negligible CT content, 0.6-0.9%). Jacobs' selection indexes (JSIs) were estimated for the experimental foliage based on dry matter (DM), CT, or crude protein (CP) intake. During both study stages, individual fecal egg counts were estimated. The JSI patterns of different plant species, based on DM, CT, or CP, were similar irrespective of infection level during stage 1 (HI, MI, and NI) or no GIN infection (stage 2). Thus, irrespective of GIN infection, goats actively selected M. bahamensis (high CT, low CP content) and V. dentata (negligible CT, high CP content) but avoided G. floribundum (high CT, low CP content) and L. leucocephala (medium CT and high CP content). Thus, natural GIN infection did not influence goats' foliage selection.

<p><strong>Background. </strong>Small ruminants that graze in the low deciduous forest (LDF) face problems related to malnutrition and gastrointestinal nematode infections (GIN). Over the past 30 years, FMVZ-UADY researchers have conducted extensive research to understand the interaction between small ruminant nutrition, plants consumed in LDF, and GINs. <strong>Objective.</strong> Review the work carried out in the FMVZ-UADY to explain why these problems of malnutrition and GIN infection occur and how to solve them. <strong>Main findings.</strong> Research shows that the complex interaction between small ruminants, LDF plants, and GINs helps explain malnutrition problems and GIN infections. Both of these problems have also been shown to abate through dietary supplementation, which must be designed to deliver the limiting nutrients in the LDF. Producers can use criteria such as weight gain and body condition score (BCS) to monitor that their animals are nutritionally adequate. To maintain strong resilience and resistance against GINs, growing animals should achieve> 100 g / day weight gain and adults should maintain> 2.5 BCS. It has also been confirmed that many LDF plant species contain secondary compounds (SC) that can affect the biology of different life stages of GIN, so they could be used as nutraceuticals. However, some SC can also adversely affect the digestion and absorption of nutrients in sheep and goats, so they must be used with care. The presence of plants containing SC with anthelmintic activity has made it possible to explore the capacity of animals to self-medicate. In these studies, it has been shown that goats do not express a “curative” self-medication behavior against GINs but do exhibit “preventive” self-medication behaviors that could allow them to limit their GIN burdens. However, animals seem to favor a preventive behavior aimed at avoiding nitrogen:energy imbalances in the consumed diet. <strong>Implications:</strong> Many LDF plant species have a high potential to be used for both nutritional and medicinal purposes in small ruminants, therefore, these species could be considered as a nutraceutical resource. <strong>Conclusions.</strong> The work carried out in the last 3 decades has shown us that the optimal use of LDF by sheep and goats will be achieved through a better understanding of the interaction between animals, their GIN and the plants of the LDF.<strong></strong></p>

PurposeIn the fight against anthelmintic resistance, targeted selective treatments (TSTs), where only a small percentage of a flock receives treatment, have become increasingly popular. Overall, implementation of such treatments can be based on various parameters including Body condition score (BCS). As infection with non-bloodsucking nematodes, frequently encountered on sheep farms in the central Mediterranean basin, commonly causes bodyweight reduction, the aim of this research is to evaluate the effectiveness of BCS as a parameter for the implementation of TSTs in lactating dairy sheep with subclinical gastrointestinal nematode (GIN) infections from the island of Sardinia, Italy.MethodsFaecal samples from 1012 ewes divided into 2 groups (third and fifth month of lactation) were collected and their BCS recorded. Faecal egg counts and coprocultures were performed for the assessment of the GIN burden and identification of present species.ResultsAn overall GIN prevalence of 85.4% with a mean eggs per gram (EPG) of faeces of 210.1 ± 347.3 was found. Teladorsagia spp. and Trichostrongylus spp. were the GIN genera most identified. Overall, animals with the lowest BCS had the highest EPG values and a negative correlation (r = − 0.163) between the EPG values and BCS of the studied animals was found, which was most significant for older sheep.ConclusionThis research confirmed BCSs and EPG values for GIN in sheep to be negatively correlated, particularly in older ewes. Application of TSTs for lactating sheep with a BCS < 2.25, especially to older ewes, could be beneficial in case of subclinical GIN infections, although further studies are needed to work out precise recommendation.

Using copper oxide wire particles or sericea lespedeza to prevent peri-parturient gastrointestinal nematode infection in sheep and goats

Gastrointestinal nematode infections were evaluated in sheep raised in Botucatu, state of São Paulo, Brazil between April 2008 and March 2011. Every month, two tracer lambs grazing with a flock of sheep were exposed to natural infection with gastrointestinal nematodes for 28 consecutive days. At the end of this period, the lambs were sacrificed for worm counts. Haemonchus contortus presented 100% of prevalence. The seasons exerted no significant influence on the mean intensity of H. contortus, which ranged from 315 worms in November 2010 to 2,5205 worms in January 2011. The prevalence of Trichostrongylus colubriformis was also 100%, with the lowest mean intensity (15 worms) recorded in February 2011 and the highest (9,760 worms) in October 2009. In the case of T. colubriformis, a significant correlation coefficient was found between worm counts vs. rainfall (r = -0.32; P <0.05). Three other nematodes species were found in tracer lambs, albeit in small numbers. Their prevalence and mean intensity (in parenthesis) were as follows: Oesophagostomum columbianum 28% (25.2), Cooperia curticei 7% (4.5) and Trichuris spp. 2% (1). In conclusion, the environmental conditions of the area proved to be highly favorable for the year-round transmission of H. contortus and T. colubriformis.

Intensive anthelmintic administration was estimated to cause drug resistancy. Research was conducted to determine the efficacy of albendazole and levamisole anthelmintic in thin-tailed sheep infected with gastrointestinal nematode at smallholder farms in Sukomulyo Village, Malang Regency. A total of 65 sheeps naturally infected with nematode worms were administered albendazole (35 tails) and levamisole (30 tails). Observation of egg per grams (EPG) was conducted using modified McMaster method. To determine treatments’ efficacy, EPG was conducted before and 2 weeks after treatments’ administration. The results showed that in farms that routinely given albendazole, mean treatment efficacy was 83.73% meanwhile in farms that were never receive albendazole was 92.23%. There were no farms that ever receive levamisole before. Mean treatment’s efficacy for levamisole was 95.84%. In conclusion, albendazole and levamisole still effective as anthelmintic towards gastrointestinal nematode infection in thin-tailed sheep. However, the possibility of drug resistance needs to be carefully observed, especially for albendazole.

Aim:Gastrointestinal parasitism is a serious constraint affecting goat production in the Philippines. This study aimed to determine the prevalence and associated risk factors of gastrointestinal nematode infection in goat-populated barangays of Baybay City, Leyte.Materials and Methods:A total of 81 households or farms were interviewed, and 450 goats were sampled for fecalysis. Fecal egg count along with egg morphological identification and coproculture for third stage larvae identification were conducted. Descriptive statistics and logistic regression analyses were carried out to determine the farm- and animal-level prevalence and risk factors.Results:Fecalysis revealed the presence of strongyle and Trichuris spp. with a farm-level prevalence of 100% and 4.94%, respectively; and animal-level prevalence of 96.22% and 4.44%, respectively. The identified strongyle genera per barangay were Haemonchus spp. (34.79%), Trichostrongylus spp. (33.29%), Oesophagostomum spp. (24.21%), Cooperia spp. (6.93%), and Chabertia spp. (0.79%). Goats older than 12 months were four times more likely to present high strongyle burden when compared to goats <6 months. With each month increase in goat’s age, the odds of acquiring strongyle infection also increased by 1.07 times. Animals kept in goat house with cemented flooring have lower odds of acquiring strongyle (odds ratio=0.12). Goats raised for leisure purposes and fed with carabao grass (Paspalum conjugatum) were 8.12 and 5.52 times more likely to acquire Trichuris, respectively.Conclusion:Most of the backyard goat raisers in Baybay City, Leyte, do not practice sound helminth control measures as shown by the high prevalence of gastrointestinal nematodes. The most relevant risk factors for gastrointestinal nematode infection were the age of the goat, type of goat house’s flooring, purpose of raising goats, and feeding practices.

Effect of feeding a blackseed meal-sericea lespedeza leaf meal pellet on gastrointestinal nematode and coccidia infection and animal performance in young goats

SUMMARY Two groups of 10 parasite-free calves were maintained either for 2 weeks on a pasture grazed by nonmedicated cattle (pasture A) or for 3 weeks on a pasture grazed by morantel sustained-release bolus-treated cattle (pasture B) for the preceding 2 years. After a 4-week holding period to allow for maturation of acquired gastrointestinal nematodes, 5 calves from each group were administered a therapeutic dose (10 mg/kg of body weight) of morantel tartrate. All calves were necropsied 1 week later, and the abomasal and small intestinal nematodes were isolated, identified, and enumerated. A comparison of efficacies between nonmedicated and morantel tartrate-treated calves of each pasture demonstrated that morantel was equally effective against the gastrointestinal nematode infections, regardless of infection source (ie, pasture A vs pasture B). The overall nematode reductions due to morantel tartrate treatment of calves that grazed pastures A and B were 98% and 96%, respectively. It was concluded that the sensitivity of gastrointestinal nematodes to morantel tartrate was not diminished in calves maintained on pasture B, which had been stocked with morantel sustained-release bolus-treated calves for the preceding 2 grazing seasons.

Infections with gastrointestinal (GI) nematodes are prevalent worldwide, despite the fact that anti-helminthic medications are regarded as safe, efficient, and widely available globally. In this review, we highlight the potential therapeutic benefits that may be realized through the clinical use of Trichuris suis and other helminths for Crohn's disease (CD). Long-lived helminthic parasites are remarkable in their ability to down-regulate host immunity, protecting themselves from elimination, and also minimize severe pathological host changes. This review summarizes what is known about the underlying mechanisms that may account for the observed patterns in humans treated with helminths for CD. The Th2 arm of the immune system is emphasized as a component of primary importance in the association between the host immune system and GI nematode infections. Although GI nematode infections in humans cause significant morbidity and mortality, the existence and nature of protective mechanisms these helminths may confer remain largely unclear.

Genetic analysis of the potential role of IgA and IgE responses against Haemonchus contortus in parasite resistance of Creole goats

Gastrointestinal nematode (GIN) infections, particularly caused by Haemonchus contortus, are a major concern in sheep farming, resulting in significant economic losses Genetic resistance, used alongside chemical control, nutrition, and pasture management, provides a sustainable strategy to mitigate these infections in industrial livestock systems The South African Dohne Merino sheep, known for their resilience and suitability for both wool and meat production, offer a potential genetic resource for breeding GIN resistance, providing an alternative to chemical control. This study utilised RNA-Seq and differential gene expression (DEG) analysis to investigate the molecular mechanisms underlying H. contortus infection in Dohne Merino sheep. Six adult ewes from Wauldby farm (Eastern Cape Province), naturally exposed to H. contortus, were selected. The animals were categorised into resistant (n = 3) and susceptible (n = 3) groups based on Estimated Breeding Values (EBVs) from faecal egg count (FEC) phenotypes. DEG analysis revealed 34 significantly differentially expressed genes (DEGs) related to immune responses and external stimuli, with involvement in key pathways such as Rap1 and PI3K-Akt signaling, linked to H. contortus resistance. Additionally, segment-specific analysis of the gastrointestinal tract identified DEGs in different regions: 146 in the abomasum, 302 in the ileum, 584 in the jejunum, and 332 in the duodenum. The findings highlight genes and pathways contributing to GIN resistance and tissue-specific response mechanisms. These insights can support the selection and breeding of sheep with enhanced resistance to H. contortus, offering a genetic approach to combating GIN infections.

Anthelmintic activity of Pistacia lentiscus foliage in two Middle Eastern breeds of goats differing in their propensity to consume tannin-rich browse