A preliminary evaluation of factors affecting an experimental system for vaccination-and-challenge with Haemonchus contortus in sheep

Adams, D.B.

doi:10.1016/0020-7519(89)90004-0

Cited by 25 publications

(8 citation statements)

References 23 publications

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“…H . contortus infections, as measured by parasite burden, faecal egg output and fertility, are considered highly variable (ADAMS, 1989) and therefore these extreme variations found when the animals were challenged could be interpreted as 'normal' variations. However, the epg counts seen in these animals when they were infected with 2500 and 5000 L-3 (CUQUERELLA et al, 1991) and 7000 L-3 were extremely close.…”

Section: H Contortusmentioning

confidence: 99%

Partial Protection of Manchego Sheep against Haemonchus contortus after a 6‐Month Postpriming Period. Preliminary Note

Cuquerella

Gómez-Muñoz

Méndez

et al. 1994

Journal of Veterinary Medicine, Series B

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Twelve to 12-5-month-old Manchego sheep which had received a Haernonchus contortus infection with 2500 infective larvae (L-3) when they were 4-4.5 months old (Al,A2) and a challenge with 5000 L-3 2 months later (Al,A2,Bl,B2), finished in both cases with thiabendazole treatment, were subjected to a homologous infection with 7000 L-3 (A1,BI) or kept as control sheep (A2,B2). Fifty days after the infection the animals were treated with rafoxanide and challenged 18 days later with 14,000 L-3 of the parasite.Wide variations were seen, not observed at the 7000 L-3 infection, after challenge among the animals' faecal egg output. Retrospective analysis of the results obtained showed that the sheep response was apparently dependent on the extent of the contact with the parasite 6 months earlier and the elapsed period between priming and infection. A significant protective response was seen at challenge in the sheep which had received 2500 + 5000 L-3 (A2), suggesting the need of a period between 120 and 180 days without infection to show a strong response.No clear correlation was seen between parasitological results and the serum antibody response estimated by ELISA along the experiment and Western blotting analysis during the challenge. However, the less reactive sheep displayed lower ELISA values and simpler immunorecognition patterns in WB.

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Section: H Contortusmentioning

confidence: 99%

Partial Protection of Manchego Sheep against Haemonchus contortus after a 6‐Month Postpriming Period. Preliminary Note

Cuquerella

Gómez-Muñoz

Méndez

et al. 1994

Journal of Veterinary Medicine, Series B

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“…The GIN infection in sheep is predominantly regulated by acquired immunity (Adams, 1989) which controls the impact of parasitism on life time productivity of grazing animals (Van Houtert and Sykes, 1996). It has been shown that two of the most promising and feasible alternatives to chemotherapy in GIN control are improved nutrition (Bown et al, 1991;Donaldson et al, 1998;Van Houtert and Sykes, 1996) and selection for genetic resistance (Woolaston, 1992).…”

Section: Introductionmentioning

confidence: 99%

Effect of dietary protein on responses of lambs to repeated Haemonchus contortus infection

Khan¹,

Sahoo²,

Sonawane³

et al. 2012

Livestock Science

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“…of animalsBreedAge (months)Immune pastDuration of infection (days)Infection doseNo. of experimentsEμFf[32]Australia622MerinoNaïve: 20,000 L 3 7–21–24–845000–10,00051[33]Australia521Merino5Naïve-Natural7–21–245000–20,0005[34]Australia522Merino2.5–6.5Natural: 5000 L 3 –6000 L 3 9–12–30–585000–6000–10,00041[35]Australia415MerinoNaïve2110,0004[36]Australia212Merino8.5–36Naïve: 20,000 L 3 2110,0002[37]Australia210Merino9.25–14Naïve24–285000–10,0002[38]Australia29MerinoNaïve-Natural21–265000–10,0002[39]Iraq210Awassi-Merino5.5Natural3910,600–13,3002[40]Brazil16Santa Ines3Natural4040001[41]Mexico14Suffolk × Dorset6.5Naïv...…”

Section: Resultsmentioning

confidence: 99%

Meta-analysis of the parasitic phase traits of Haemonchus contortus infection in sheep

et al. 2017

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BackgroundThe parasitic nematode Haemonchus contortus shows highly variable life history traits. This highlights the need to have an average estimate and a quantification of the variation around it to calibrate epidemiological models.MethodsThis paper aimed to quantify the main life history traits of H. contortus and to identify explanatory factors affecting these traits using a powerful method based on a systematic review and meta-analysis of current literature. The life history traits considered are: (i) the establishment rate of ingested larvae; (ii) the adult mortality rate; (iii) the fertility (i.e. the number of eggs laid/female/day); and (iv) fecundity of female worms (i.e. the number of eggs per gram of faeces).ResultsA total of 37 papers that report single experimental infection with H. contortus in sheep and published from 1960 to 2015, were reviewed and collated in this meta-analysis. This encompassed 115 experiments on 982 animals. Each trait was analysed using a linear model weighted by its inverse variance. The average (± SE) larval establishment rate was 0.24 ± 0.02, which decreased as a function of the infection dose and host age. An average adult mortality rate of 0.021 ± 0.002) was estimated from the literature. This trait varied as a function of animal age, breed and protective response due to prior exposure to the parasite. Average female fertility was 1295.9 ± 280.4 eggs/female/day and decreased in resistant breeds and previously infected hosts. Average faecal egg count at necropsy was 908.5 ± 487.1 eggs per gram of faeces and varied as a function of infection duration and host resistance. The average sex ratio of H. contortus was 0.51 ± 0.006.ConclusionThis work is the first systematic review to summarise the available information on the parasitic phase of H. contortus in sheep. The results of the meta-analysis provide robust estimates of life history traits for parametrization of epidemiological models, their expected variation according to experimental factors, and provides correlations between these.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2131-7) contains supplementary material, which is available to authorized users.

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A preliminary evaluation of factors affecting an experimental system for vaccination-and-challenge with Haemonchus contortus in sheep

Cited by 25 publications

References 23 publications

Partial Protection of Manchego Sheep against Haemonchus contortus after a 6‐Month Postpriming Period. Preliminary Note

Partial Protection of Manchego Sheep against Haemonchus contortus after a 6‐Month Postpriming Period. Preliminary Note

Effect of dietary protein on responses of lambs to repeated Haemonchus contortus infection

Meta-analysis of the parasitic phase traits of Haemonchus contortus infection in sheep

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