Piglet Scours – Could it be Clostridium?

Neonatal scours can have a number of causes including bacterial, viral and parasitic. Although one of the principal bacterial causes of piglet scours has, and continues to be; Enterotoxigenic E. coli (ETEC), Clostridium is increasingly seen as a causative agent of piglet diarrhea.

Studies have shown that Clostridium perfringens types A and C as well as Clostridium difficile can be the causative agents of neonatal scours.

Clostridium perfringens type C

C. perfringens type C is the causative agent of necrotic enteritis and in acute cases, causes hemorrhagic diarrhea. Type C produces both alpha and beta toxins. The disease symptoms are usually seen in young piglets. Three days of age is the average age of emergence. Mortality in litters from non–immune sows can reach 100%.

Clostridium perfringens type A

Although previously considered to be part of the normal intestinal flora of swine, C. perfringens type A has more recently been shown to be involved in enteric disease under some conditions. Determination of the significance of the isolation of C. perfringens type A is often based upon clinical symptoms, histology, isolation of Clostridium in large numbers, particularly in the absence of other pathogens and detection of the toxins. Type A produces alpha toxin, but does not produce beta toxin. Some strains produce a powerful enterotoxin associated with sporulation.

The vegetative and sporulative forms have been shown to produce different disease symptoms. The sporulative form causes severe but transient, watery diarrhea. The vegetative form tends to result in creamy or pasty pale scours. Mortality rate in these piglets is low, but morbidity can be significant. (Diseases of Swine 8 th Edition, 1999)

Clostridium difficile

C. difficile has been shown to be the causative agent of neonatal scours with increasing frequency as seen in a study by Yaeger et al from Iowa State University (J Vet Diagn Invest, July 2002). The study looked at pathogens present in 100 neonatal diarrhea cases. In this study, at least one toxin – positive animal was identified in 55% of the cases, demonstrating "the emergence of C. difficile as an important pathogen of neonatal swine”.

C. difficile is often not cultured due to its strict anaerobic requirements for growth, but may be a pathogen to consider when diagnostics rule out other enteric pathogens.

Testing Options

When Clostridium perfringens is suspected as a possible causative agent, submission of tied off loops of the small intestine are recommended for pathogen isolation. These can be submitted with rectal swabs to be screened for ETEC as well.

ELISA testing can be done on gut contents to determine if enterotoxin is present and the isolated organisms can be genotyped using PCR technology to provide a typing identification and confirm presence of toxin genes. Note that ELISA testing and PCR are often available through your regional laboratory.

Presence of toxins produced by C. difficile in gut contents or feces can be determined by ELISA testing. Once C. difficile has been implicated as a pathogen of concern, tied gut loops or live piglets should be sent to a regional laboratory equipped to perform the required anaerobic bacteriology. Indi cate that C. difficile is suspected on the submission form.

Implications for Autogenous Bacterin Use

Use of a sow vaccination for control of C. perfringens type C infections in piglets is well accepted.

Confirmation of the presence of toxins and diagnostics to rule out other causative agents such as viruses and parasites helps to confirm that C. perfringens type A is the principal pathogen and improve the results seen with this bacterin.

We have experience in combining Clostridium bacterins to include C. difficile, C. perfringens and pathogenic E. coli strains that are impacting the herd.

 

 

Clostridium Statistics

Total number of autogenous bacterin orders containing Clostridium isolate(s) from Gallant Custom Laboratories.

	2007	2008
Number of swine clients ordering Clostridium bacterins	7	40
Containing Clostridium difficile and clostridium perfringens	0	6
Containing Clostridium perfringens with alpha and beta 2 toxin	Unknown	40

Gallant tests all swine Clostridium perfringens production lots for presence of alpha and beta 2 toxin regardless of whether the isolate has been genotyped. Generally the isolates are screened for the presence of the alpha and beta 2 toxin genes for selection as a candidate for bacterin production. If the isolate is negative for the beta 2 toxin gene it is not recommend ed for use as a bacterin strain. Therefore, 100% of the strains used in swine bacterin production are positive for both alpha and beta 2 toxin s at our lab. This can either be tested prior to production using PCR genotyping or after production using a dot blot assay to detect the presence of the toxins in the culture. Bacterins are used to vaccinate sows and gilts pre - farrowing. Currently we are making bacterins for clients in Alberta, Saskatchewan, Manitoba, Ontario, Quebec and the Maritimes. We are seeing an sharp increase in the use of Clostridial bacterins for pre-farrowing vaccination.

Diagnostic Cases

In 2008 our lab handled 49 swine enteric cases that screened for Clostridium or were Clostridium isolates received from other labs for bacterin production. Of these 49 cases, 46 were positive for Clostridium perfringens . Of these 46 cases 13 were genotyped against the 5 Clostridium perfringens types (A, B, C, D, and E) either by our lab or another lab. Of the strains that were genotyped from swine, only 1 (one) was Clostridium perfringens type A with alpha toxin but negative to beta 2 toxin. However, as mentioned above, if it was used for an autogenous bacterin the presence of alpha and beta 2 toxin s were checked during production and all swine isolates were positive to both alpha and beta 2 toxin.