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Clinical problems due to encephalomyocarditis virus infections in two pig herds

View Article: PubMed Central - PubMed

ABSTRACT

Background: Infections with encephalomyocarditis virus may cause myocarditis and sudden death in young pigs and reproduction disorders in sows. The presence of encephalomyocarditis virus infected rodents is considered a major risk factor for transmission of the virus to pigs. There is currently no effective treatment. Tightening up biosecurity, applying effective rodent control and reducing stress are the main control measures.

Case presentation: Two farrow-to-finish herds suffering from problems with sudden death are presented. In herd A, suckling piglets from 3 to 12 days old were dying acutely whereas in herd B, piglets at the end of the nursery period (8–10 weeks) were showing identical problems. A presumptive diagnosis of encephalomyocarditis virus infection was made because typical lesions were observed in some of the affected pigs. These lesions were not always present in pigs dying acutely or in some cases the lesions were very subtle. Therefore other causes had to be ruled out based upon clinical history, clinical signs and diagnostic tests. A conclusive diagnosis was finally established by showing encephalomyocarditis virus in heart tissue using conventional gel-based polymerase chain reaction tests. The real-time PCR test that gave initially negative result was further optimized to avoid false negative results.

Conclusions: Typical lesions are not always present in piglets infected with encephalomyocarditis virus, indicating the importance of examining multiple animals. Problems in suckling piglets may occur in affected herds without reproductive problems in sows. Transmission routes of EMCV in swine are not fully understood. A stand-empty period following thorough cleaning and disinfection is recommended for controlling EMC virus infections.

No MeSH data available.


Heart of a piglet showing a subtle EMCV lesion. Arrows indicating subtle necrosis of the myocard
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Fig2: Heart of a piglet showing a subtle EMCV lesion. Arrows indicating subtle necrosis of the myocard

Mentions: The examinations performed in herd A are summarized in Table 4. The first two episodes of sudden death problems in 3 day old piglets (December 2013 and January 2014) were not thought to be related with EMCV because no signs indicative for EMCV were observed. Instead E. coli was suspected as the causative pathogen. However, in January 2014 no virulence factors for E. coli (F4, F5, F6 or F41 adhesion factors; LT, STa and STb toxins) were found. An intoxication appeared to be unlikely due to the clustering of problems. Dead piglets did not appear to have been crushed by the sow and they were often heavier than the remaining pigs. The microclimate appeared to be good for the piglets. The first examination suggesting EMCV took place in June 2014 and was performed by the herd veterinarian. Upon necropsy of a 5 day old piglet, a very subtle lesion on the heart compatible with EMCV was observed (Fig. 2).Table 4


Clinical problems due to encephalomyocarditis virus infections in two pig herds
Heart of a piglet showing a subtle EMCV lesion. Arrows indicating subtle necrosis of the myocard
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5382511&req=5

Fig2: Heart of a piglet showing a subtle EMCV lesion. Arrows indicating subtle necrosis of the myocard
Mentions: The examinations performed in herd A are summarized in Table 4. The first two episodes of sudden death problems in 3 day old piglets (December 2013 and January 2014) were not thought to be related with EMCV because no signs indicative for EMCV were observed. Instead E. coli was suspected as the causative pathogen. However, in January 2014 no virulence factors for E. coli (F4, F5, F6 or F41 adhesion factors; LT, STa and STb toxins) were found. An intoxication appeared to be unlikely due to the clustering of problems. Dead piglets did not appear to have been crushed by the sow and they were often heavier than the remaining pigs. The microclimate appeared to be good for the piglets. The first examination suggesting EMCV took place in June 2014 and was performed by the herd veterinarian. Upon necropsy of a 5 day old piglet, a very subtle lesion on the heart compatible with EMCV was observed (Fig. 2).Table 4

View Article: PubMed Central - PubMed

ABSTRACT

Background: Infections with encephalomyocarditis virus may cause myocarditis and sudden death in young pigs and reproduction disorders in sows. The presence of encephalomyocarditis virus infected rodents is considered a major risk factor for transmission of the virus to pigs. There is currently no effective treatment. Tightening up biosecurity, applying effective rodent control and reducing stress are the main control measures.

Case presentation: Two farrow-to-finish herds suffering from problems with sudden death are presented. In herd A, suckling piglets from 3 to 12 days old were dying acutely whereas in herd B, piglets at the end of the nursery period (8–10 weeks) were showing identical problems. A presumptive diagnosis of encephalomyocarditis virus infection was made because typical lesions were observed in some of the affected pigs. These lesions were not always present in pigs dying acutely or in some cases the lesions were very subtle. Therefore other causes had to be ruled out based upon clinical history, clinical signs and diagnostic tests. A conclusive diagnosis was finally established by showing encephalomyocarditis virus in heart tissue using conventional gel-based polymerase chain reaction tests. The real-time PCR test that gave initially negative result was further optimized to avoid false negative results.

Conclusions: Typical lesions are not always present in piglets infected with encephalomyocarditis virus, indicating the importance of examining multiple animals. Problems in suckling piglets may occur in affected herds without reproductive problems in sows. Transmission routes of EMCV in swine are not fully understood. A stand-empty period following thorough cleaning and disinfection is recommended for controlling EMC virus infections.

No MeSH data available.