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Probability of introducing porcine epidemic diarrhea virus into Danish pig herds by imported spray-dried porcine plasma

View Article: PubMed Central - PubMed

ABSTRACT

Background: Porcine epidemic diarrhea virus (PEDV) has never been reported in Denmark, but it has been found in Europe, Asia and North America. Ultimately, PEDV has been associated with devastating outbreaks in pig farms. We developed a stochastic simulation model to carry out a quantitative risk assessment and to estimate the annual probability (PPlasma) of introducing PEDV into the Danish pig population, by imported spray-dried porcine plasma (SDPP). The model was based on information from literature and Danish feed companies. Moreover testing the batch of raw blood (before the spray-drying) was considered as potential risk mitigation measure in the future.

Results: The median PPlasma was 0.2 % (90 % P.I.: 0.003 %; 2.6 %). Hence, the annual probability of introducing PEDV into the Danish pig population by imported SDPP appeared very low, and on average at least one introduction each 500 years – corresponding to 1/0.002 - could be expected. However, if PEDV survived the spray-drying process and storage was insufficient to completely remove the remaining viable virus (e.g. due to storage at low environmental temperatures during a short time period) the PPlasma was 4.7 % (0.06 %; 57.4 %). In that case, on average, at least one PEDV introduction each 21 years could be expected. This probability could be reduced to 0.3 % (0.004 %; 6.0 %) if the raw batch of blood could be tested before drying (corresponding to at least one introduction each 333 years on average).

Conclusions: This study provides preliminary and important information on the probability of introducing PEDV into the Danish pig population by use of SDPP. Currently PED is not a notifiable disease in the EU and uncertainty was present in our estimates due to possible underreporting in EU Member States, from which SDPP is imported into Denmark. In the future, PED might become a notifiable disease, and in such a case, new knowledge could become available on its epidemiology. Moreover, SDPP could be imported more safely if: producers find a way to substantiate freedom from disease (at least) in herds delivering blood for SDPP, the batch of blood tests negative for PEDV and conditions for processing/storage required by the international laws are respected.

No MeSH data available.


Related in: MedlinePlus

SDPP producing diagram. N.B. Here we give a general diagram, and as stated by Sampedro et al. [20], there are several parameters that could vary between spray dryers (e.g. the flow rate inputs, the retention time etc.). Those parameters could affect the survivability of PEDV during the spray-drying process [3, 20]
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Fig1: SDPP producing diagram. N.B. Here we give a general diagram, and as stated by Sampedro et al. [20], there are several parameters that could vary between spray dryers (e.g. the flow rate inputs, the retention time etc.). Those parameters could affect the survivability of PEDV during the spray-drying process [3, 20]

Mentions: Pig blood products, such as spray-dried porcine plasma (SDPP), which can be fed to piglets as a feed supplement, have been suspected as a possible route of virus spread [3, 11]. However, some studies suggested that SDPP is not a likely source of infectious virus [13, 14]. In fact, for the spray-drying process (Fig. 1), efficient combinations of temperature and time should be used. Usually the temperature is ≥ 80 °C throughout the substance and the plasma transit time in the dryer is between 20 and 90 s [15–20]. Nevertheless, it would be helpful to clarify exactly which combinations of temperature and time are needed to inactivate PEDV.Fig. 1


Probability of introducing porcine epidemic diarrhea virus into Danish pig herds by imported spray-dried porcine plasma
SDPP producing diagram. N.B. Here we give a general diagram, and as stated by Sampedro et al. [20], there are several parameters that could vary between spray dryers (e.g. the flow rate inputs, the retention time etc.). Those parameters could affect the survivability of PEDV during the spray-drying process [3, 20]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5382482&req=5

Fig1: SDPP producing diagram. N.B. Here we give a general diagram, and as stated by Sampedro et al. [20], there are several parameters that could vary between spray dryers (e.g. the flow rate inputs, the retention time etc.). Those parameters could affect the survivability of PEDV during the spray-drying process [3, 20]
Mentions: Pig blood products, such as spray-dried porcine plasma (SDPP), which can be fed to piglets as a feed supplement, have been suspected as a possible route of virus spread [3, 11]. However, some studies suggested that SDPP is not a likely source of infectious virus [13, 14]. In fact, for the spray-drying process (Fig. 1), efficient combinations of temperature and time should be used. Usually the temperature is ≥ 80 °C throughout the substance and the plasma transit time in the dryer is between 20 and 90 s [15–20]. Nevertheless, it would be helpful to clarify exactly which combinations of temperature and time are needed to inactivate PEDV.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Porcine epidemic diarrhea virus (PEDV) has never been reported in Denmark, but it has been found in Europe, Asia and North America. Ultimately, PEDV has been associated with devastating outbreaks in pig farms. We developed a stochastic simulation model to carry out a quantitative risk assessment and to estimate the annual probability (PPlasma) of introducing PEDV into the Danish pig population, by imported spray-dried porcine plasma (SDPP). The model was based on information from literature and Danish feed companies. Moreover testing the batch of raw blood (before the spray-drying) was considered as potential risk mitigation measure in the future.

Results: The median PPlasma was 0.2 % (90 % P.I.: 0.003 %; 2.6 %). Hence, the annual probability of introducing PEDV into the Danish pig population by imported SDPP appeared very low, and on average at least one introduction each 500 years – corresponding to 1/0.002 - could be expected. However, if PEDV survived the spray-drying process and storage was insufficient to completely remove the remaining viable virus (e.g. due to storage at low environmental temperatures during a short time period) the PPlasma was 4.7 % (0.06 %; 57.4 %). In that case, on average, at least one PEDV introduction each 21 years could be expected. This probability could be reduced to 0.3 % (0.004 %; 6.0 %) if the raw batch of blood could be tested before drying (corresponding to at least one introduction each 333 years on average).

Conclusions: This study provides preliminary and important information on the probability of introducing PEDV into the Danish pig population by use of SDPP. Currently PED is not a notifiable disease in the EU and uncertainty was present in our estimates due to possible underreporting in EU Member States, from which SDPP is imported into Denmark. In the future, PED might become a notifiable disease, and in such a case, new knowledge could become available on its epidemiology. Moreover, SDPP could be imported more safely if: producers find a way to substantiate freedom from disease (at least) in herds delivering blood for SDPP, the batch of blood tests negative for PEDV and conditions for processing/storage required by the international laws are respected.

No MeSH data available.


Related in: MedlinePlus