In this fourth and final piece, we will deal with Coccidiosis and Clostridium.
In the previous articles, we have discussed some of the main pathogens causing neonatal diarrhea in pigs: Enterotoxigenic Escherichia coli, Clostridium perfringens type C, and viruses (TGEV, PEDV, rotavirus). In this fourth and last piece, we will deal with Coccidiosis and Clostridium.
Coccidiosis in the pig is caused by a parasite called Cystoisospora suis (C. suis; formerly named Isospora suis). There are several other coccidia (from Eimeria genus), which can infect pigs, but they usually don’t have negative consequences, even if in some cases they can cause disease in young adults. C. suis is a frequent pathogen in suckling piglets worldwide. For instance it was reported that it is present more than 75% of farms in Germany, Austria and Switzerland, and close to 70% in or China or Poland. It is an intracellular protozoan parasite, with a life cycle that can be divided into three stages.
First, piglets become infected by oral uptake of sporulated oocysts which are present in faeces of previously contaminated animals. Once the oocysts are ingested, sporozoites are released from these oocysts and they can penetrate epithelial cells of the small intestine, replicate, and gradually destroy intestinal cells. This endogenous stage leads to necrosis of enterocytes, resulting in intestinal lesions such as villus atrophy and fusion. The intestinal damage often results in non-haemorrhagic and malabsorptive, watery or greasy diarrhea, usually yellowish to white with an unpleasant smell. Pathological lesions and clinical signs can be observed about 3 to 5 days after infection (usually between 5 and 21 days of age), while the excretion of oocysts in faeces occurs after five days.
Generally, morbidity is high while mortality is relatively low, but the piglet’s health status can be greatly affected in presence of bacterial or viral co-infections. The economic impact of coccidiosis in pigs can be important because piglets that were affected often show poor weight gain and low performance.
To avoid coccidiosis in piglets, the key is to prevent contact with the parasite, by reducing the numbers of oocysts in the environment, or inactivating them through proper hygiene measures, for instance steam-cleaning or using disinfectants with anticoccidial properties. In contaminated animals, the use of anticoccidial drugs is helpful. Because C. suis causes intestinal damage during its cycle, supporting the enterocytes during the challenging phase can help reduce the negative impact of the disease.
In a large scale trial conducted in Spain (Study 20-039-P-P) it was observed that pre-weaning mortality was higher in farrowing rooms positive to coccidiosis. When using Tonisity Px from days 2-8 of life (an isotonic protein drink, which directly targets and supports the enterocytes and help them to be stronger), it was observed that pre-weaning mortality was drastically reduced in the rooms affected by coccidiosis. Therefore, this suggests that Tonisity Px can be successfully used as a complementary gut health support alongside the anticoccidial treatment.
Clostridium perfringens type A and Clostridium difficile
Clostridium bacteria are gram-positive spore-forming bacilli. Both C. perfringens type A and C. difficile have been described as important causes of neonatal diarrhea in piglets, however the importance of these pathogens is not clear, because both bacteria are part of the normal intestinal microbiota in piglets, and their toxins can also be found at comparable levels in intestinal contents from healthy and sick piglets.
Clostridium perfringens type A (CpA) produces toxins and does not seem to cause diarrhea through adhesion or destruction of the intestinal epithelium. In humans, CpA produces an enterotoxin and causes food poisoning. It was suggested that this toxin is involved in CpA enteritis in pigs, however the presence of the enterotoxin gene in porcine CpA is not very common.
Typical signs of CpA enteritis in new-born pigs include creamy, whitish diarrhea that can be observed around one to two days after birth. In the intestine, necrosis of villi tips can be seen, although not always.
Clostridium difficile is an important cause of diarrhea in humans. This bacterium can also cause neonatal diarrhea in pigs, through the action of specific toxins. It affects piglets mostly in the first week of life, and symptoms are observed in about one-third of affected litters. Piglets infected by C. difficile often have soft to almost liquid faeces, loss of body condition, and sometimes dyspnoea, abdominal distention, and scrotal oedema.
Other pathogens, such as different strains of E. Coli, or Enterococcus faecium, as well as Salmonella or some parasites and viruses, can also cause diarrhea in new-born pigs, but they are much less common than the ones we discussed in this series of articles.
The table below summarizes the most important infectious causes of neonatal porcine diarrhea, the typical age when pigs are affected, and the typical symptoms.
|Enterotoxigenic Escherichia coli (ETEC)||12h to 4 days, also 2-3 weeks after weaning||Liquid, yellowish faeces with variable incidence of diarrhea, from rather mild to abundant, watery diarrhea leading to severe dehydration and quick death. Small intestine dilated with congestion of the intestinal wall.|
|Clostridium perfringens type C||First week of life and up to 2 to 3 weeks of age||Faeces with signs of intestinal haemorrhage. Under autopsy, mucosal necrosis in the small intestine with excess of blood in the vessels.|
|TGEV and PEDV||All stages of life||Fluid, yellowish intestinal contents. Because of villus atrophy, intestines appear as thin walled and transparent.|
|Rotavirus||First 7 weeks of life, most frequent at 2-3 weeks of age||White to yellow diarrhea (also known as ‘white scours’), sometimes associated with vomiting. Pale intestines. Symptoms are generally less severe than with TGE.|
|Coccidiosis (Cystoisospora suis)||From 5 to 21 days of age||Intestinal damage often resulting in non-haemorrhagic and malabsorptive, watery or greasy diarrhea, usually yellowish to white with an unpleasant smell.|
|Clostridium perfringens type A and Clostridium difficile||Mostly in the first week of life||Creamy, whitish diarrhea that can be observed around one to two days after birth. In the intestine, necrosis of villi tips can be seen, although not always.|
If you missed the other articles in the series, you can find part one here, part two here and part three here.