Genetic resistance of three genotypes of goats to experimental infection with Haemonchus contortus

SummaryThe possible existence of strain and breed differences in the response of sheep to primary infections withHaemonchus contortuswas examined by comparing the establishment and pathogenic effects of the parasite in Scottish Blackface and Finn Dorset sheep grouped according to haemoglobin type and infected with 7–10000 3rd-stage larvae. Homozygous haemoglobin A-type sheep of both breeds had lower worm burdens and faecal egg outputs, and suffered less severe clinical and pathophysiological disturbances than animals homozygous for haemoglobin B. In addition, Scottish Blackface sheep displayed similar advantages over Finn Dorsets with the same haemoglobin type and variations in the severity of the disease as judged by a variety of pathophysiological indices correlated closely with parasite numbers. It was therefore concluded that genetic resistance operated primarily against worm establishment and that, barring the unlikely involvement of non-specific physiological factors, this was controlled by the immune response elicited. The nature of this response is unknown, but appeared to operate only against the larval stages, since the size and metabolic activities of the surviving worms were similar in all animals. In a subsequent experiment, designed to examine the response of Scottish Blackface sheep to heavy infection (45000 larvae), there was no correlation between worm establishment and haemoglobin type. This was possibly due to a delayed immune response arising from exposure to excessive amounts of antigen.

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Combination of immunostimulants with moxidectin in the treatment of animals experimentally infected with Haemonchus contortus

Semina Ciências Agrárias ◽

10.5433/1679-0359.2021v42n2p707 ◽

2021 ◽

Vol 42 (2) ◽

pp. 707-720

Author(s):

Luiza Pires Portella ◽

◽

Fagner D'ambroso Fernandes ◽

Luís Antônio Sangioni ◽

Fernanda Ramos ◽

...

Keyword(s):

Drug Resistance ◽

Experimental Infection ◽

Haemonchus Contortus ◽

Infected Sheep ◽

Subtropical Region ◽

Anthelmintic Drug ◽

Parasitic Resistance ◽

Efficacy Of Treatment

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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Intake and digestibility of naïve kids differing in genetic resistance and experimentally parasitized (indoors) with Haemonchus contortus in two successive challenges1

Journal of Animal Science ◽

10.2527/jas.2008-1702 ◽

2009 ◽

Vol 87 (7) ◽

pp. 2367-2375 ◽

Cited By ~ 12

Author(s):

J. C. Bambou ◽

R. Arquet ◽

H. Archimède ◽

G. Alexandre ◽

N. Mandonnet ◽

...

Keyword(s):

Haemonchus Contortus ◽

Genetic Resistance

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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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