Experimental quantification of vaccine-induced reduction in virus transmission

Jong, M.C.M. de; Kimman, Tjeerd G.

doi:10.1016/0264-410x(94)90229-1

Cited by 177 publications

(127 citation statements)

References 15 publications

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“…We used a stochastic SIR model (susceptible-infectiousrecovered model) as described by De Jong and Kimman [15], in which S is the total number of susceptible, I the total number of infectious and R the total number of recovered animals. In the model we classified the calves as infected (I) when either clinical signs were present or when a sample tested positive in the virus isolation (VI) assay, the RT-PCR or NS ELISA or when a four-fold increase in VNT titer was observed.…”

Section: Quantification Of Transmission and Statistical Methodsmentioning

confidence: 99%

Vaccination against foot and mouth disease reduces virus transmission in groups of calves

Orsel

Dekker²,

Bouma

et al. 2005

Vaccine

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The aim of vaccination during an epidemic of foot and mouth disease (FMD) is not to induce clinical protection, but to reduce virus transmission. Since no quantitative data were available on the effectiveness of vaccination in cattle, we investigated whether a single vaccination against FMD could reduce virus transmission in groups of calves by estimating the reproduction ratio R, i.e. the average number of secondary cases caused by one infectious animal in a susceptible population. We performed two experiments with six groups of either four vaccinated or four non-vaccinated calves each. Vaccination was carried out with O 1 Manisa vaccine. Two weeks after vaccination, two calves per group were inoculated intra-nasally with FMDV field isolate O/NET2001. The two other calves were contact-exposed to the inoculated calves. Contact infections were observed by clinical inspection, virus isolation and RT-PCR on heparinised blood, oro-pharyngeal fluid and probang samples and antibody response to non-structural proteins. In all six non-vaccinated groups, transmission to contact-exposed calves was recorded; in the vaccinated groups, virus transmission was observed to one contact-exposed calf. In the non-vaccinated groups R c was 2.52 and significantly above 1, whereas in the vaccinated groups R v = 0.18 and significantly below 1, indicating that vaccination may successfully be applied as additional intervention tool to reduce virus transmission in a future epidemic of FMD.

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Section: Quantification Of Transmission and Statistical Methodsmentioning

confidence: 99%

Vaccination against foot and mouth disease reduces virus transmission in groups of calves

Orsel

Dekker²,

Bouma

et al. 2005

Vaccine

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“…Direct transmission can be studied in transmission experiments where a number of pigs is inoculated with the virus and subsequently virus transmission to contact pigs within the same pen is studied [4]. The transmission rate b and the basic reproduction ratio (R 0 ) can then be used to quantify the transmission.…”

Section: Introductionmentioning

confidence: 99%

Effect of strain and inoculation dose of classical swine fever virus on within-pen transmission

Weesendorp

Backer²,

Stegeman

et al. 2009

Vet. Res.

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-To improve the understanding of the dynamics and options for control of classical swine fever (CSF), more quantitative knowledge is needed on virus transmission. In this study, virus excretion and within-pen transmission of a strain of low, moderate and high virulence were quantified. Furthermore, the effect of inoculation dose on excretion and transmission were studied. The transmission was quantified using a stochastic susceptible-exposed-infectious-recovered (SEIR) model. Five transmission trials were conducted with ten pigs each. In each trial, three pigs were inoculated with the low virulent strain Zoelen, a low (10 2 TCID 50 ), middle (10 3.5 TCID 50 ), or high dose (10 5 TCID 50 ) of the moderately virulent strain Paderborn, or the highly virulent strain Brescia. The other seven pigs in each trial served as contact pigs. None of the pigs inoculated with the low dose of the Paderborn strain were infected. When it was assumed that the infectiousness of the pigs coincided with virus isolation positive oropharyngeal fluid and/or faeces, no significant differences in transmission rate b and basic reproduction ratio R 0 between the high inoculation dose of the Paderborn strain (b = 1.62/day, R 0 = 35.9) and the Brescia strain (b = 2.07/day, R 0 = 17.5) were observed. When the middle dose of the Paderborn strain was used for inoculation, the b (5.38/day) was not significantly higher than the Brescia strain or the high inoculation dose of the Paderborn strain, but the R 0 (148) was significantly higher. Infection with the Zoelen strain resulted in a significantly lower b and R 0 (b = 0/day, R 0 = 0) than the other strains.classical swine fever / transmission parameter / virus excretion / within-pen transmission

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“…Transmission can be studied under experimental conditions [10][11][12][13][14]. These experiments have the advantage that the effect of infectivity as well as susceptibility on transmission are combined.…”

Section: Introductionmentioning

confidence: 99%

Estimating transmission parameters of F4+ E. coli for F4-receptor-positive and -negative piglets: one-to-one transmission experiment

Geenen

Meulen²,

Bouma

et al. 2004

Epidemiol. Infect.

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SUMMARY F4+Escherichia coli is an important agent of post-weaning diarrhoea in piglets. Piglets that express an adhesion site for F4+ E. coli in their small intestine (F4R+) shed higher numbers of F4+ E. coli than piglets lacking this site (F4Rx). We hypothesized that F4R+ piglets are more infectious and more susceptible for F4+ E. coli. This implies that in populations with F4R+ and F4Rx piglets, the transmission would be dependent on the frequency of both types of animals. To quantify the difference in infectiousness and susceptibility, a one-to-one transmission experiment was performed with 20 pairs consisting of one inoculated and one contact piglet. Based on the contact infections observed, transmission parameters were estimated with generalized linear models. F4R+ piglets were infectious for other piglets and the reproduction ratio (R 0 ) for homogeneous F4R+ populations, that is the average number of secondary infections that one F4R+ pig will cause during its entire infectious period in a population of susceptible F4R+ individuals only, was estimated as 7 . 1. F4R+ piglets were more susceptible than F4Rx piglets and reducing the fraction of F4R+ piglets of a population will reduce transmission. It was calculated that in order to prevent major outbreaks of F4+ E. coli (R 0 <1), the fraction of F4R+ piglets must be lower than 0 . 14.

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Experimental quantification of vaccine-induced reduction in virus transmission

Cited by 177 publications

References 15 publications

Vaccination against foot and mouth disease reduces virus transmission in groups of calves

Vaccination against foot and mouth disease reduces virus transmission in groups of calves

Effect of strain and inoculation dose of classical swine fever virus on within-pen transmission

Estimating transmission parameters of F4+ E. coli for F4-receptor-positive and -negative piglets: one-to-one transmission experiment

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