Mites as vectors for scrapie

Wisniewski, H J; Sigurðarson, Sigurður; Rubenstein, Richard; Kascsak, R.; Carp, R. I.

doi:10.1016/s0140-6736(96)90310-4

Cited by 70 publications

(55 citation statements)

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“…LEX also allows us to distinguish the effect of biological events, such as lambing, where the routes of infection are already known and may occur in addition to other sources of infection. Vectors of infection (Wisniewski et al, 1996;Post et al, 1999) and mechanisms of infectivity (Andréoletti et al, 2002b; Tuo et al, 2002) have been described in the literature.According to Fig. 1, the model located the highest risk to have occurred at some point in 1995, between the second and third lambing periods.…”

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confidence: 99%

Polygenic variation and transmission factors involved in the resistance/susceptibility to scrapie in a Romanov flock

Díaz

Vitezica

Rupp

et al. 2005

Journal of General Virology

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Data from 4049 Romanov sheep belonging to a flock affected by natural scrapie were analysed by using survival-analysis techniques. Failure time was defined as the period of time between first exposure to infection and the date that animals left the flock with scrapie signs. Four hundred and forty-seven sheep were identified as 'scrapie animals'. Several models, including level of exposure as a time-dependent effect, PrP genotype, sex, age at first exposure, litter size and factors related to vertical transmission, were tested. The best model was extended to a sire-dam frailty model, in order to estimate the polygenic variation in addition to that in the Prnp gene. A combined effect of rearing type and the dam's disease status was detected. Thus, only sheep with a low degree of exposure to infection as lambs (lambs reared artificially and born out of a healthy dam) showed less risk than others. Animals first exposed to infection at older ages seemed to be less susceptible to scrapie. In this Romanov population, new genotypes (AHQ/AHQ, AHQ/VRQ, ARR/VRQ and ARR/ARQ) were associated with risk, suggesting the effect of genotypes on the incubation period of animals. Polygenic variance was responsible for 21 % of the total genetic variability that was related to susceptibility to scrapie. Therefore, the genetic susceptibility to scrapie may be explained by the joint effect of point mutations at the Prnp major gene and a number of genes that modulate its effect. INTRODUCTIONTransmissible spongiform encephalopathies (TSEs), or prion diseases, are a group of fatal degenerative disorders of the central nervous system. They comprise a group of diseases that affect many species. TSEs are characterized by the accumulation of an abnormal isoform of the cellular prion protein, named PrP Sc . Scrapie is a TSE affecting sheep and goats. TSE in sheep, as in mice and humans, is controlled genetically (Hunter et al., 1989;Hunter, 1997;Prusiner & Scott, 1997;Elsen et al., 1999). Susceptibility to scrapie, which may be evaluated by mortality rate and incubation period, is mainly controlled by polymorphisms in the Prnp gene. Several point mutations located at codons 136 (T, A, V), 154 (R, H) and 171 (R, Q, H, K) of the gene have been associated with natural scrapie (e.g. Hunter, 1997). The ARR allele is associated with resistance and VRQ is associated with susceptibility (e.g. Hunter et al., 1996;Elsen et al., 1999). However, there are alleles, such as ARQ, ARH and AHQ, that behave differently depending on the breed (e.g. Hunter, 1997;Thorgeirsdottir et al., 1999). It has also been demonstrated that there is an interaction between the genotype of the host and the scrapie strain (Goldmann et al., 1994;O'Rourke et al., 1997; Barron et al., 2003). In the mouse, the incubation period of the disease has been associated with the PrP genotype (Moore et al., 1998) and with the prion strain inoculated (Bruce et al., 1991). However, polymorphism of the Prnp gene does not explain the total variation in incubation period that is observed, indicati...

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confidence: 99%

Polygenic variation and transmission factors involved in the resistance/susceptibility to scrapie in a Romanov flock

Díaz

Vitezica

Rupp

et al. 2005

Journal of General Virology

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“…The idea that hay mites could be carriers of the scrapie prion protein PrP sc has its origin in Iceland [1], where the concentration of mites connected with this process is normally higher than that found in the Basque regions in this study ( Table 2). A mean of 50,000 mites /kg hay was found in Icelandic farms, and concentrations of more than 1 million mites/ kg were not unusual [15].…”

Section: Mite Faunisticsmentioning

confidence: 47%

“…Mites in hay have been linked to outbreaks of scrapie [1]. Scrapie is the sheep equivalent to Bovine Spongiform Encephalitis (BSE).…”

Section: Introductionmentioning

confidence: 99%

“…This suggests that as-yet unidentified environmental factors might be involved in outbreaks of the disease. During a search for possible agents of recurrent scrapie in Iceland it was found, that the mites in stored hay could be carriers of PrP Sc [1,5]. Storage mites in hay or 'haymites' have been investigated primarily in connection with human work related respiratory diseases [6,7], but *Address correspondence to this author at the Hojgaardsparken 23, DK 3660 Stenlose, Denmark; Tel: +45 48184157; E-mail: thallas@hotmail.com almost nothing is known about the fauna of hay mites in most countries, including the Basque regions in France and Spain.…”

Section: Introductionmentioning

confidence: 99%

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Hay Mite Communities in Sheep Farms from French and Spanish Basque Regions with regard to Scrapie Infection

Hallas¹,

Garcia-Prez²,

Hurtado³

et al. 2009

TOVSJ

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It has been suggested that the mites connected with the decay of stored hay may be involved in the transmission of scrapie, a neurological disorder in sheep. To find out whether there are any obvious differences in the mite fauna in hay that could be related to outbreaks of scrapie in sheep, we analysed the hay fauna from 23 farms in the Basque regions in France and Spain, areas with high and very low incidence of scrapie, respectively. We did find some differences in the composition of the fauna, and a species such as Pygmephorus spp. was more prevalent in scrapie-infected farms, and particularly in highly scrapie-infected farms. The former species is associated with late stages in the biological degradation of stored hay and could be linked to the disease. Besides being the first record of the composition of the hay mite fauna in Spain and France our finding of differences in mite communities in hay from scrapie versus non-scrapie farms is a further indication of the possible association of certain mite species with scrapie.

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“…Inclusive posibilitaría el análisis y trasferencia de embriones a madres con genotipo susceptible, pues fetos portadores del alelo ARR (resistencia a priones) que desarrollen en madres sucesptibles o que lleguen a desarrollar enfermedad pueden resistir y no acumular la proteína infecciosa (Wisniewski et al, 1996;Andreoletti et al, 2002). Por otro lado, los trabajos realizados en la selección de ovinos resistentes a scrapie concluyen que no han tenido efecto negativo contra características productivas deseadas como la producción de carne o lana (Moussaoui et …”

Section: Discussionunclassified

Detección del Gen PrP de Scrapie en Ovinos Junín

Rivera

Maturrano

Aguilar³

et al. 2015

Rev. investig. vet. Perú

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El objetivo del presente trabajo fue establecer la frecuencia de genotipos de resistencia y susceptibilidad a padecer la enfermedad de scrapie en ovejas Junín. Se analizaron 56 muestras de sangre de ovinos de una unidad de producción privada de la región central del Perú. Se extrajo el ADN y los productos de PCR fueron analizados mediante digestión enzimática con endonucleasas de restricción que reconocen los polimorfismos del gen PrP. Se pudo identificar 4 de los 5 haplotipos reportados para el gen PrP: ARR (48.2%), ARQ (35.7%), AHQ (10.7%) y VRQ (5.4%). Además, se encontró 7 de los 15 genotipos reportados para el gen Prión: ARR/ARR (17.9%), ARR/AHQ (10.7%), ARR/ ARQ (42.9%), ARQ/AHQ (10.7%), ARQ/ARQ (7.1%), ARR/VRQ (7.1%) y ARQ/VRQ (3.6%). El 82.1% de las ovejas presentaron genotipos de resistencia a la enfermedad y el 17.9% presentó genotipos de susceptibilidad.

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Mites as vectors for scrapie

Cited by 70 publications

References 2 publications

Polygenic variation and transmission factors involved in the resistance/susceptibility to scrapie in a Romanov flock

Polygenic variation and transmission factors involved in the resistance/susceptibility to scrapie in a Romanov flock

Hay Mite Communities in Sheep Farms from French and Spanish Basque Regions with regard to Scrapie Infection

Detección del Gen PrP de Scrapie en Ovinos Junín

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