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Dietary probiotics may enhance gut health by directly competing with pathogenic agents and through immunostimulatory effects. These properties are recognized in the context of bacterial and viral pathogens, but less is known about interactions with eukaryotic pathogens such as parasitic worms (helminths). In this study we investigated whether two probiotic mixtures (comprised of Bacillus amyloliquefaciens, B. subtilis , and Enterococcus faecium [BBE], or Lactobacillus rhamnosus LGG and Bifidobacterium animalis subspecies Lactis Bb12 [LB]) could modulate helminth infection kinetics as well as the gut microbiome and intestinal immune responses in pigs infected with the nodular worm Oesophagostomum dentatum . We observed that neither probiotic mixture influenced helminth infection levels. BBE, and to a lesser extent LB, changed the alpha- and beta-diversity indices of the colon and fecal microbiota, notably including an enrichment of fecal Bifidobacterium spp. by BBE. However, these effects were muted by concurrent O. dentatum infection. BBE (but not LB) significantly attenuated the O. dentatum -induced upregulation of genes involved in type-2 inflammation and restored normal lymphocyte ratios in the ileo-caecal lymph nodes that were altered by infection. Moreover, inflammatory cytokine release from blood mononuclear cells and intestinal lymphocytes was diminished by BBE. Collectively, our data suggest that selected probiotic mixtures can play a role in maintaining immune homeostasis during type 2-biased inflammation. In addition, potentially beneficial changes in the microbiome induced by dietary probiotics may be counteracted by helminths, highlighting the complex inter-relationships that potentially exist between probiotic bacteria and intestinal parasites.

The intensity and prevalence of different gastrointestinal nematode species vary across regions worldwide. Oesophagostomum radiatum commonly shows a high occurrence in young cattle. O. radiatum causes anaemia, hypoproteinaemia, and immunopathological changes in the large intestine wall, impairing calves’ body weight gain. This study aimed to assess the impact of natural O. radiatum infection on haematological parameters and immune responses in 23 Nellore calves, considering sex-based differences. Assessments included Oesophagostomum egg count (EPG), worm count, packed cell volume (PCV), total plasma protein, histopathological and immunohistochemistry analyses. A large number of parasites attached to the colon mucosa were observed, along with massive nodule formation and haemorrhagic lesions, mainly within a 20–30 cm-long segment adjacent to the nodules. The maximum mean egg shedding was approximately 165 EPG for males and 173 EPG for female calves; however, males presented a significantly higher worm count (969 ± 200.5) than females (460 ± 99.5). There were significant positive correlations between the total O. radiatum worm count and O. radiatum EPG for both female and male calves. Significant negative correlations were observed between the total O. radiatum worm count and PCV in female calves. Our results demonstrated that natural O. radiatum infection in Nellore calves induced marked immunopathological alterations, including chronic inflammatory responses that impaired intestinal function. Sex-related differences suggested that female calves may develop more effective tissue responses. These findings emphasise the economic impact of subclinical infections and reinforce the importance of control strategies to minimise productivity losses in cattle.

Oesophagostomum bifurcum larvae, cultured from human stools collected in northern Ghana, were used to establish experimental infections in monkeys. A patent infection was established in a rhesus monkey (Macaca mulatta) and this infection was used to generate larvae to inoculate additional monkeys. In all, 17 animals were inoculated. Thirteen of 15 animals developed antibodies to the infection between 19 and 62 days post inoculation (PI); two animals had a positive response before inoculation. Four of ten animals developed patent infections between 88 and 134 days and passed eggs in the faeces. Egg shedding was consistent in only one animal, but at low levels of one or two eggs per 2 mg direct smear, and extended over a 400 day period. In the other three animals, egg shedding was sporadic and of only 2–4 weeks duration. In seven animals necropsied between 19 and 22 days PI, one to 17 early fourth-stage larvae were recovered from nodules in the bowel wall; in an eighth animal examined at 314 days, six immature adult worms (early fifth stage) were recovered from nodules in the bowel wall. The morphological features and growth of these recovered larvae are described. Three animals were inoculated with larvae that had been dried for one week at 28°C; two animals began shedding eggs at 128 and 134 days PI, respectively. The present results suggest that the parasite obtained from humans is poorly adapted to lower primate hosts, and supports the concept that Oesophagostomum bifurcum found in humans and monkeys in the same geographical region of northern Ghana and Togo are distinct and that the infections in humans are not likely to represent zoonotic infections acquired from monkeys.

The in vitro culture of 3rd-stage Oesophagostomum columbianum larvae to the 4th larval stage was achieved in a culture medium of components with a molecular weight less than 6,000. The small mol wt components of chick embryo extract and sheep serum used in the culture medium were prepared by gel filtration. About 60% of the larvae successfully completed the 3rd molt and reached the 4th stage in the simplified medium. Development compared favorably with larvae cultured in vitro in complex media and with in vivo development. Culture medium in which larvae had developed was fractionated by gel filtration and the excluded peak further separated by polyacrylamide disc electrophoresis. The presence of worm antigens was demonstrated. Immunoelectrophoretic studies demonstrated the presence of more precipitating antibodies in mucosal extracts than in sera from hyperinfected sheep.

In northern Ghana and Togo, Oesophagostomum bifurcum infects an estimated 250,000 people, as determined by cultures of stool samples. The juvenile stages of the helminth develop within colonic wall nodules, causing Dapaong tumor or multinodular disease, at the rate of 1 case per week at Nalerigu Hospital in Ghana. Our aim was to discover whether suspected colonic-wall pathology is ultrasonographically visible in asymptomatic individuals living in the area where O. bifurcum is endemic. A total of 464 persons from 3 villages, ranging from highly infected to noninfected, were examined with ultrasonography. Anechogenic colonic lesions with posterior wall enhancement were observed in 71 (54.2%) of 131 and 57 (24.5%) of 233 persons from the villages of endemicity, and no lesions were seen in persons from the village outside the area of endemicity. We describe the lesions noted in this study as nodules caused by O. bifurcum, on the basis of their association at a population level with prevalence of larvae in stools, their expected ultrasonographic appearance and distribution (on the basis of our surgical experience with oesophagostomiasis), and the lack of a convincing differential diagnosis.