Haemonchus contortus: Abomasal transmural potential difference and permeability changes associated with experimental infection in sheep

Considering the importance of Haemonchus contortus infection in herds along with parasitic resistance, the goal of this study was to evaluate the influence of the administration of adjuvants alone or in combination with anthelmintics for the treatment of H. contortus, in experimentally infected sheep. Thirty sheep of the Texel breed of both genders, raised in a herd located in the subtropical region of Brazil, were used in this experiment. Experimental infection with H. contortus was performed in sheep, and the infected sheep were then separated into groups for the administration of antiparasitic and immunostimulant drugs. The results obtained from the excretion of eggs per gram of feces and the count of parasites during necropsy affirm that the use of adjuvants in combination with anthelmintics is associated with higher efficacy of treatment, lower rate of reinfection, and retardation in the development of anthelmintic drug resistance by H. contortus. Based on these results, we can conclude that the combination of anthelmintics and immunostimulants may favor potential anthelmintic treatments for H. contortus.

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Gastro-duodenal motor and transit disturbances associated with Haemonchus contortus infection in sheep

Parasitology ◽

10.1017/s0031182000044905 ◽

1982 ◽

Vol 84 (2) ◽

pp. 367-374 ◽

Cited By ~ 26

Author(s):

L. Bueno ◽

A. Dakkak ◽

J. Fioramonti

Keyword(s):

Acid Secretion ◽

Water Content ◽

Gastric Acid Secretion ◽

Flow Rate ◽

Haemonchus Contortus ◽

Ionic Permeability ◽

Duodenal Motility ◽

Permeability Changes ◽

Duodenal Ph ◽

Motor Disturbances

SUMMARYAbomasal and duodenal motility was investigated by electromyography in 4 lambs fitted with permanent abomasal and duodenal cannulae and infected twice with 25000 Haemonchus contortus larvae at an interval of 39 days. In addition, abomasal and duodenal pH, flow rate of digesta of the duodenum, and faecal water content were determined. The 80–90 min cycles of antral contractions were shortened for at least 3 weeks after infection. This was accompanied by a 26% increase in the number of duodenal migrating myoelectric complexes/day during the intra-parietal development of the larvae (10–12 days). Concomitantly, the duodenal flow of digesta increased from 215 ± 22 ml/h to 318 ± 15 ml/h 4 days after infection and was associated with a higher water content of the faeces. The frequency of the migrating myoelectric complexes, but not the duration of antral motor cycles (or the duodenal flow rate), was correlated with both gastric (P < 0·01) and duodenal (P < 0·05) pH after the first and second infections. The duodenal flow rate was correlated with the Cl− concentration of the abomasal contents (P < 0·01) and with the duodenal pH (P < 0·05). It is concluded that, (i) the duodenal motor disturbances associated with experimental H. contortus infection are related to the alterations in abomasal gastric acid secretion which occurs during the histotrophic phase of larval development and (ii) the increased duodenal flow is a consequence of ionic permeability changes of the gastro-intestinal mucosae.

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Experimental infection by Haemonchus contortus in lambs: influence of disease on purine levels in serum

Parasitology ◽

10.1017/s0031182013002370 ◽

2014 ◽

Vol 141 (7) ◽

pp. 898-903 ◽

Cited By ~ 9

Author(s):

LUCAS T. GRESSLER ◽

ALEKSANDRO S. DA SILVA ◽

CAMILA B. OLIVEIRA ◽

ANDRESSA S. SCHAFER ◽

ADELINA R. AIRES ◽

...

Keyword(s):

High Pressure ◽

Uric Acid ◽

Liquid Chromatography ◽

High Pressure Liquid Chromatography ◽

Experimental Infection ◽

Post Infection ◽

Haemonchus Contortus ◽

Inflammatory Process ◽

Group A ◽

Group B

SUMMARYThe aim of this study was to evaluate the purine levels of lambs experimentally infected with Haemonchus contortus. A total of 12 healthy lambs were divided into two groups, composed of 6 animals each: Group A represented the healthy animals (uninfected), while in Group B the animals were infected with 15 000 larvae of H. contortus. Blood was drawn on days 15, 45 and 75 post-infection (PI) in order to perform the purine analysis (ATP, ADP, AMP, adenosine, inosine, hypoxanthine, xanthine and uric acid) by high pressure liquid chromatography (HPLC) in serum. On day 15 PI a significant (P<0·05) increase in the levels of ATP and inosine was observed in the infected animals, unlike the levels of ADP, adenosine, xanthine and uric acid which were reduced. On day 45 PI a significant (P<0·05) increase in the ATP and xanthine levels in infected animals was observed, contrasting with reduced levels of ADP and uric acid. Finally, on day 75 PI an increase occurred in the levels of ATP, adenosine and hypoxanthine in infected lambs, concomitant with a reduction in the levels of ADP and uric acid (P<0·05). These changes in purine levels may influence the inflammatory process and the pathological events.

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