gastrins and Trichostrongyloidiasis

Abomasal Trichostrongylidae infections are still today an important cause of scarce performances in small ruminants, mainly when bred in extensive systems. Although morpho-biology, symptomatology, prophylaxis and therapy of these infections are well known, other, such as physiopathology, are less investigated. The aim of the present note is to review the more important physiopathogenetic mechanisms of abomasal Trichostrongylidae infections, with special emphasis to Haemonchus spp. and Teladorsagia spp. The parasitic anorexia due to the action of gastrin, the defects of digestion due to hypocloridia, the scarce intestinal absorption and anaemia caused by H. contortus are discussed. Furthermore, the effects of hypersensitivity sometimes caused by these abomasal nematodes are examined. A better knowledge of physiopathological mechanisms can represent an important factor to understand the relationships between host and parasite, useful to set up new diagnostic techniques or new therapeutic and prophylactic protocols for sanitary education and control plans of these important and widespread parasitic infections.

Topics: Abomasum; Anemia, Hemolytic; Animals; Anorexia; Female; Gastrins; Goat Diseases; Goats; Haemonchiasis; Haemonchus; Host-Parasite Interactions; Hypoalbuminemia; Male; Sheep; Sheep Diseases; Stomach Diseases; Trichostrongyloidea; Trichostrongyloidiasis

Pathophysiological changes in the ruminant abomasum caused by Ostertagia infections include changes in the activity and concentration of gastrointestinal enzymes and hormones. Under certain circumstances, increases in concentration also occur in the bloodstream and, as such, are detectable. Determination of serum pepsinogen levels is useful in evaluating the risk or presence of ostertagiasis Type I in a herd. It seems less reliable when used to diagnose (pre) ostertagiasis in individual animals. Measurement of the concentration of other zymogens is not useful. The variations in methodology to determine pepsinogen levels (e.g. biochemical and immunological measurements) are discussed. Serum gastrin levels are, generally, increased in animals with ostertagiasis. At present, gastrin is mainly determined by RIA assays using human gastrin antibodies, but few baseline data are available on normal levels in ruminants. The use of gastrin determination as a diagnostic tool in Ostertagia-infected ruminants is limited.

Topics: Abomasum; Animals; Clinical Enzyme Tests; Gastrins; Ostertagiasis; Pepsinogens; Ruminants; Trichostrongyloidiasis

This is the first integrated study of the effects on gastric secretion, inflammation and fundic mucins after infection with L3 T. circumcincta and in the very early period following transplantation of adult worms. At 3 months-of-age, 20 Coopworth lambs were infected intraruminally with 35,000 L3; infected animals were killed on Days 5, 10, 15, 20 and 30 post-infection and 6 controls on either Day 0 or 30 post-infection. Another 15 Romney cross lambs received 10,000 adult worms at 4-5 months-of-age though surgically-implanted abomasal cannulae and were killed after 6, 12, 24 and 72 hours; uninfected controls were also killed at 72 hours. Blood was collected at regular intervals from all animals for measurement of serum gastrin and pepsinogen and abomasal fluid for pH measurement from cannulated sheep. Tissues collected at necropsy were fixed in Bouin's fluid for light microscopy, immunocytochemistry and mucin staining and in Karnovsky's fluid for electron microscopy. Nodules around glands containing developing larvae were seen on Day 5 p.i., but generalised effects on secretion occurred only after parasite emergence and within hours after transplantation of adult worms. After L3 infection, there were maximum worm burdens on Days 10-15 post-infection, together with peak tissue eosinophilia, inhibition of gastric acid secretion, hypergastrinaemia, hyperpepsinogenaemia, loss of parietal cells, enlarged gastric pits containing less mucin and increased numbers of mucous neck cells. After adult transplantation, serum pepsinogen was significantly increased after 9 hours and serum gastrin after 18 hours. Parallel changes in host tissues and the numbers of parasites in the abomasal lumen suggest that luminal parasites, but not those in the tissues, are key drivers of the pathophysiology and inflammatory response in animals exposed to parasites for the first time. These results are consistent with initiation of the host response by parasite chemicals diffusing across the surface epithelium, possibly aided by components of ES products which increased permeability. Parietal cells appear to be a key target, resulting in secondary increases in serum gastrin, pit elongation, loss of surface mucins and inhibition of chief cell maturation. Inflammation occurs in parallel, and could either cause the pathology or exacerbate the direct effects of ES products.

Topics: Animals; Gastric Mucins; Gastrins; Larva; Pepsinogen A; Sheep; Sheep Diseases; Stomach Diseases; Stomach, Ruminant; Trichostrongyloidea; Trichostrongyloidiasis

:  Because there appeared to be no data available on serum gastrin concentrations in animals infected with Marshallagia marshalli, and considering the high prevalence of this parasite in livestock throughout many countries, we decided to perform research in the field using experimental infection. After surgical implantation of abomasal cannula into 10 male Baluchi sheep, each animal was orally infected with 5,000 M. marshalli larvae. Serum gastrin concentrations and abomasal pH were measured with a human ELISA kit and a PHM LE438 standard pH electrode, respectively. According to the results obtained from the study, serum gastrin increased after 14 and 21 days post-infection (dpi), while abomasal pH increased after 7 dpi and reached a maximal value 16 dpi. The increase in serum gastrin concentration was revealed 6 days after elevation in abomasal pH, which could be the result of reduced acid secretion. Generally, the present study pointed out that a limited number of M. marshalli could increase serum gastrin concentrations.

Topics: Abomasum; Animals; Feces; Female; Gastrins; Hydrogen-Ion Concentration; Male; Parasite Egg Count; Sheep; Sheep Diseases; Trichostrongyloidea; Trichostrongyloidiasis

This study was conducted to evaluate the effects of tactical treatments with ivermectin against trichostrongyles in first-season grazing heifer calves in the Danish marshland. A group of Black-Pied Friesian calves was turned out in early May on a permanent pasture naturally infected with trichostrongyle larvae. In late July, when high herbage infectivity started to appear, the pasture was divided into two plots of equal size, which from then and until housing in late October were each grazed by half of the original group of calves. One of these groups was given three anthelmintic treatments with ivermectin at 4-week intervals starting in late July. The other group served as non-treated controls. Ostertagia ostertagi and Cooperia oncophora were the predominant trichostrongyles. Nematodirus helvetianus was observed on few occasions. Although the animals were exposed to a high herbage infectivity from July onwards, the anthelmintic treatments conferred a significant reduction in trichostrongyle loads, as evidenced by an almost complete cessation of egg excretion and a significant lowering of pepsinogen and gastrin levels in the blood. This was reflected in higher weight gains.

Topics: Animals; Cattle; Cattle Diseases; Feces; Female; Gastrins; Intestinal Diseases, Parasitic; Ivermectin; Ostertagia; Ostertagiasis; Parasite Egg Count; Pepsinogens; Seasons; Serum Albumin, Bovine; Trichostrongyloidea; Trichostrongyloidiasis; Weight Gain

Radioimmunoassay of plasma gastrin has shown that a hypergastrinaemia occurs in yearling sheep, after infection with 10(6) infective third stage larvae of Haemonchus contortus. Plasma gastrin concentrations began to rise two to four days after infection, that is, at about the same time as, or slightly before, the abomasal pH was observed to increase.

Topics: Abomasum; Animals; Gastrins; Haemonchiasis; Hydrogen-Ion Concentration; Radioimmunoassay; Sheep; Sheep Diseases; Trichostrongyloidiasis

Blood gastrin and pepsinogen responses to a single infection with 100,000 Ostertagia ostertagi infective larvae in lactating dairy cows were investigated. None of the infected cows showed signs of clinical ostertagiasis, nor was there any difference in live weight gain, milk yield or faecal egg count between groups. Pepsinogen levels of the infected group were significantly elevated between days 3 and 24 after infection (peak 1041 mU tyrosine; day 14). In contrast, there was no significant difference in blood gastrin levels between infected and control animals suggesting that few adult worms had become established in the former group. These data are compared with the increases in both gastrin and pepsinogen levels recorded in susceptible calves exposed to the same level, pattern and strain of ostertagia infection in a previous experiment. It is suggested that gastrin assay may be of value in adult cattle for indicating when elevated pepsinogen levels are merely associated with a rise in larval intake and not with the establishment of large adult worm burdens.

Topics: Animals; Cattle; Cattle Diseases; Female; Gastrins; Lactation; Ostertagiasis; Pepsinogens; Pregnancy; Trichostrongyloidiasis

Parasite-free, 4-month-old-calves were inoculated with Ostertagia ostertagi and/or Trichostrongylus axei, followed 6 weeks later by inoculation with increasing doses of O ostertagi for 8 weeks in the 2 groups (n = 4) of calves that had been given O ostertagi. Gastrin immunoreactivity concentration in serum was measured before and after infection and was correlated with changes in mucosal thickness. Gastrin immunoreactivity concentration in preinoculation control sera ranged from 95.2 to 287.1 pg/ml, and increased values were measured in all parasitized calves after 15 weeks. Significantly (P less than 0.05) increased serum gastrin immunoreactivity concentration compared with the preinfection value, was found in calves infected with O ostertagi or T axei, and highly significant (P less than 0.01) values were observed in calves infected with both parasites. Abomasal mucosal hyperplasia was observed in all parasitized calves; increased mucosal thickness and mucosal cross-sectional area were most prominent in calves infected with O ostertagi and T axei.

Topics: Abomasum; Animals; Cattle; Cattle Diseases; Gastric Mucosa; Gastrins; Hyperplasia; Ostertagiasis; Trichostrongyloidiasis; Trichostrongylosis

Topics: Animals; Gastrins; Haemonchiasis; Hemoglobins; Male; Pepsinogens; Sheep; Sheep Diseases; Trichostrongyloidiasis

Topics: Abomasum; Animals; Gastric Mucosa; Gastrins; Hyperplasia; Organ Size; Ostertagiasis; Sheep; Sheep Diseases; Trichostrongyloidiasis

Topics: Abomasum; Animals; Cattle; Cattle Diseases; Diet; Gastrins; Hydrogen-Ion Concentration; Ostertagia; Ostertagiasis; Poaceae; Trichostrongyloidiasis

Calves infected by surgical transplantation of adult Ostertagia ostertagi had raised levels of plasma pepsinogen and those in which the largest number of worms established also had elevated plasma gastrin concentrations. Despite the elevated plasma pepsinogen values, the abomasal pH of the animals did not change significantly, and there was no significant difference in the percentage establishment of adult parasites in calves previously infected with O ostertagi third stage larvae and those which had been maintained parasite-naive before transplant.

Topics: Abomasum; Animals; Cattle; Cattle Diseases; Gastrins; Hydrogen-Ion Concentration; Ostertagiasis; Pepsinogens; Trichostrongyloidiasis

The sequential development of Type I and Type II ostertagiasis over a 2-year period in the same naturally infected cattle is described for the first time. Particular reference is made to biochemical and serological changes. Positive relationships were demonstrated between the clinical signs of both Type I and Type II disease, and marked increases in the levels of plasma pepsinogen, plasma gastrin and antibody titres to adult Ostertagia antigen. At necropsy, there were significant relationships between the combined total of adult and developing 5th stage larvae of Ostertagia spp. and the levels of both plasma pepsinogen and gastrin. By the end of the second grazing season the cattle had acquired an immunity to infection with Ostertagia spp. and had very low burdens of this parasite at necropsy. However some of these cattle maintained elevated plasma pepsinogen levels when under natural challenge by Ostertagia spp. larvae and the aetiology of these changes and the problems of diagnosis using this parameter are discussed. Similar trends of infection were observed for Cooperia oncophora, although resistance to the parasite developed more rapidly.

Topics: Abomasum; Animals; Antibodies; Antigens, Helminth; Cattle; Cattle Diseases; Feces; Gastrins; Hydrogen-Ion Concentration; Intestinal Diseases, Parasitic; Larva; Male; Ostertagia; Ostertagiasis; Parasite Egg Count; Pepsinogens; Seasons; Trichostrongyloidiasis

Radio-immunoassay of plasma gastrin showed that hypergastrinaemia developed in sheep during experimental infections with Ostertagia circumcincta. Elevations of plasma gastrin occurred within 8 days of the first dose of infective larvae, with the most marked increase being after 11-20 days when adult worms would be expected to be present in the abomasum. Increases of plasma gastrin levels from 69.0 +/- 7.6, 28.7 +/- 5.3, 48.7 +/- 5.9 and 60.6 +/- 9.4 pg/ml before infection to maxima of 650, 230, 900 and 750 pg/ml respectively were recorded in 4 sheep infected for the first time. In 2 others which had been previously infected and then treated with anthelmintic, plasma gastrin rose from 16.0 +/- 4.0 and 377 +/- 87 pg/ml to maxima of 260 and 900 pg/ml at 24 and 29 days after re-infection, respectively. The cause of hypergastrinaemia has not been established. The elevation of abomasal pH which occurs in ostertagiasis may result in increased gastrin levels but is thought not to be the only cause since plasma gastrin increased before the abomasal pH rose and developed in sheep infected for a second time although their abomasal contents remained at pH 4.0 or lower. The presence of the parasite is critical for development of hypergastrinaemia as shown by return of the gastrin level to normal following therapy with an anthelmintic. It was shown that the parasites do not depend on the hypergastrinaemia since O. circumcincta became established in antrectomized sheep in which hypergastrinaemia did not develop.

Topics: Animals; Female; Gastric Acid; Gastrins; Hydrogen-Ion Concentration; Ostertagiasis; Sheep; Sheep Diseases; Stomach; Trichostrongyloidea; Trichostrongyloidiasis

Topics: Abomasum; Animals; Duodenum; Gastrins; Ostertagiasis; Sheep; Sheep Diseases; Trichostrongyloidiasis

Sheep and calves prepared with separated, innervated pouches made from the acid secreting region of the abomasum were given single or multiple infections of Ostertagia spp and comparisons were made of the secretory changes of parasitised and non-parasitised mucosa by means of cannulas placed in the abomasum and pouch. Contrary reactions of the parasite-free pouches and infected main part of the abomasum are described and explained in terms of a two-part hypothesis. The inhibitory effect on acid secretion of the abomasum (resulting in its contents being pH 5 to 7) was postulated to be due to the direct suppressive effects of substances released locally by parasites or injured host tissues, whereas increased secretion of the hormone, gastrin, was thought to account for the stimulatory effects of infection on acid secretion from the pouches. In sheep treated with anthelmintic and then reinfected the inhibitory effects on abomasal pH were not obtained. The hypersecretion from the pouches still persisted.

Topics: Abomasum; Animals; Cattle; Gastric Juice; Gastrins; Gastritis; Ostertagiasis; Sheep; Sheep Diseases; Trichostrongyloidiasis

Topics: Animals; Gastrins; Gastritis; Ostertagiasis; Sheep; Sheep Diseases; Trichostrongyloidiasis