Design and analysis of small-scale transmission experiments with animals

Velthuis, A.G.J.; Bouma, A.; Katsma, W.E.A.; Nodelijk, G.; Jong, M.C.M. de

doi:10.1017/s095026880600673x

Cited by 96 publications

(102 citation statements)

References 14 publications

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“…Further, the optimal frequency of contact animal replacement needs to be determined. Theoretical models have been devised to help plan small-scale transmission experiments [110][111][112]. These theoretical developments focused on experiments with the usual set-up where infected and contact animals were brought into contact for the measure pathogen load, symptoms, immune response, behaviour... Figure 6.…”

Section: Discussionmentioning

confidence: 99%

Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge

Handel

Rohani

2015

Phil. Trans. R. Soc. B

109

181

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The progression of an infection within a host determines the ability of a pathogen to transmit to new hosts and to maintain itself in the population. While the general connection between the infection dynamics within a host and the population-level transmission dynamics of pathogens is widely acknowledged, a comprehensive and quantitative understanding that would allow full integration of the two scales is still lacking. Here, we provide a brief discussion of both models and data that have attempted to provide quantitative mappings from within-host infection dynamics to transmission fitness. We present a conceptual framework and provide examples of studies that have taken first steps towards development of a quantitative framework that scales from within-host infections to population-level fitness of different pathogens. We hope to illustrate some general themes, summarize some of the recent advances and—maybe most importantly—discuss gaps in our ability to bridge these scales, and to stimulate future research on this important topic.

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Section: Discussionmentioning

confidence: 99%

Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge

Handel

Rohani

2015

Phil. Trans. R. Soc. B

109

181

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“…In order to assess intervention strategies in a transmission model the probability of a minor outbreak due to a too small number of seeder birds and a low R 0 should be avoided (Velthuis et al, 2007). The set-up of this experiment virtually excludes this possibility, with 10 seeder birds and a lower limit R 0 of 4.7.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, all simulations of the experiment resulted in major outbreaks. Based on power calculations for much smaller groups (Velthuis et al, 2007), a single repetition of this experiment for both a control group and a vaccine group should be enough to assess effectiveness of a vaccine if the vaccine can reduce R 0 to a value below 1. Observation of the poults for 28 days after inoculation seems to be enough, because all contact poults had been shedding parasites at 14 days p.i., leaving enough time to infect the maximum number of birds if the β is lower.…”

Section: Discussionmentioning

confidence: 99%

Quantification of parasite shedding and horizontal transmission parameters inHistomonas meleagridis-infected turkeys determined by real-time quantitative PCR

et al. 2015

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To gain more insight into the within flock transmission of Histomonas meleagridis, the shedding of parasites was quantified by a newly developed real-time quantitative (q)PCR and the basic reproduction number (R 0 ) and the mean number of secondary infections per infectious bird per day in a susceptible population (β) of H. meleagridis in the absence of heterakis were assessed. Forty turkeys were divided into two groups of 10 and 30 birds at 14 days of age. Birds of the first group were inoculated with 200,000 histomonads each, the second group served as a susceptible contact group. Cloacal swabs were taken at −1, 1, 4, 7, 9, 11, 14, 18 and 21 days post inoculation (p.i.) to assess the shedding of the parasite by the qPCR (detection limit 330 histomonads/ml droppings). The experiment ended at 28 days p.i. Mortality was 100% in the inoculated birds and started at day 12 p.i., while in the contacts, it was 83% and started at 16 days p.i. Shedding started 1 day after the inoculation in both groups. The mean shedding levels (and 95% CI) expressed as parasite equivalents per gram cloacal content on a log 10 scale in the inoculated, contact birds that died and contact birds alive were 2.0 (1.6-2.4), 1.6 (1.4-1.9) and 1.2 (0.5-2.0), respectively. Birds that died shed histomonas more often and were infectious for 13.4 days; in contrast, those that recovered were infectious for 5.7 days. R 0 was estimated to be 8.4 and β 0.70. Simulations made with the parameters obtained were in agreement with the experimental results, confirming their validity.

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“…The other five birds (I) were inoculated at 12 weeks of age. The contact birds were placed back with the inoculated birds in the same room the day after the challenge (therefore I:C was 5:5 [6]). At day 28 post challenge (p.c.)…”

Section: Methodsmentioning

confidence: 99%

“…Transmission experiments are suitable for studying the effect of vaccination on virus transmission in general [6]. Such experiments are performed under controlled settings, enabling to quantify the effect of different parameters on transmission; for example the host species, the infectious dose, the virus strain, and, especially, vaccination.…”

Section: Introductionmentioning

confidence: 99%

Effect of H7N1 vaccination on highly pathogenic avian influenza H7N7 virus transmission in turkeys

Bos¹,

Nielen²,

Koch³

et al. 2008

Vaccine

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a b s t r a c tThis study describes the results of a transmission experiment with highly pathogenic avian influenza (HPAI) H7N7 virus in 12-week-old turkeys. Cloacal and tracheal swabs as well as serum samples were taken to monitor the infection both in inoculated and in susceptible contact turkeys, which were all either unvaccinated, vaccinated once or vaccinated twice with H7N1. Swabs were tested by real-time RT-PCR and serum samples with hemagglutination inhibition test (HI). Unvaccinated contact birds had a mean infectious period of 6.2 days, and an estimated transmission rate parameter of 1.26 per infectious bird per day. However, no virus shedding was found in inoculated vaccinated turkeys and thus we concluded that vaccination with H7N1 protected against challenge with HPAI H7N7 virus.

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Design and analysis of small-scale transmission experiments with animals

Cited by 96 publications

References 14 publications

Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge

Crossing the scale from within-host infection dynamics to between-host transmission fitness: a discussion of current assumptions and knowledge

Quantification of parasite shedding and horizontal transmission parameters inHistomonas meleagridis-infected turkeys determined by real-time quantitative PCR

Effect of H7N1 vaccination on highly pathogenic avian influenza H7N7 virus transmission in turkeys

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