In previous articles, we described some general points related to neonatal diarrhea in piglets, and we discussed about two of the main pathogens causing such symptoms, which are Enterotoxigenic Escherichia coli and Clostridium perfringens type C. In this third piece, we focus on viruses: Transmissible gastroenteritis virus (TGEV), Porcine epidemic diarrhea virus (PEDV), and rotavirus, which can also cause diarrhea during the first week of life.

TGEV and PEDV 

TGEV and PEDV are two viruses from the group of Coronaviridae, a family of enveloped, positive-strand RNA viruses which affect amphibians, birds, and mammals. Both viruses are infecting piglets which ingest contaminated material, mostly faeces. Once they reach the small intestine, they will replicate in enterocytes (intestinal absorptive cells) and will not only cause villus atrophy, altering intestinal sodium transport and impairing absorption of nutrients, but will also lead to diarrhoea.

TGEV can be found in most of the countries producing swine, but in the last 30 to 40 years, the clinical impact of TGEV has been reduced in Europe following the spread of Porcine Respiratory Coronavirus (PRCV), a respiratory virus very closely related to TGEV which ensures immunity against that digestive virus.

PEDV was first observed and identified in Western Europe (UK, Belgium) in the 1970s and later was found in other countries. It is now less frequent in Europe, but has spread to other continents, such as Asia and the Americas. Severe PEDV outbreaks were for instance reported in 2013-2014 in the USA and Canada.

Pigs of all age can suffer from TGEV and PEDV infection, but the most susceptible are very young pigs. When they are less than 2 weeks old, it is possible to observe up to 100% mortality following vomiting and a severe diarrhea.

Rotavirus  

Porcine rotaviruses are quite common and found in most of the countries where pigs are raised.  In some territories, up to 100% of the adult pig population is seropositive. Rotavirus infections can happen in in many species, including man, but the porcine rotaviruses infect only swine.

Similar to TGEV, the rotavirus will infect enterocytes in the small intestine, it can also develop in the epithelium of the large intestine. When it replicates, the enterocytes are destroyed and villi are damaged. White to yellow diarrhoea (also known as ‘white scours’), sometimes associated with vomiting, will then appear, but the symptoms are generally less severe than with TGE. If management is good, and provided enough colostrum was consumed, piglets are usually protected by the maternal immunity during the first weeks of life and mortality is usually low. Piglets who survive are then potentially becoming carriers. A combined infection with other pathogens, such as TGE or E. Coli, will cause more severe disease and higher mortality

Rotaviruses are very stable in the environment, being resistant to temperature or pH changes, to many chemicals substances, including disinfectants. For that reason, rotaviruses can be found in most of the farms and baby pigs can get contaminated by other pigs, including sows, or the environment. Rotaviruses are however sensitive to formaldehyde and chlorine-based disinfectants, provided the surfaces are previously cleaned.

Because Tonisity Px (an isotonic protein drink) directly targets and supports the enterocytes and help them to be stronger, there are many reports and experiments demonstrating that supplying this solution to piglets from days two to eight of life helps reduce the incidence of intestinal viruses, especially PEDV and rotaviruses, which results in lower piglet mortality and a faster recovery.

If you missed the other articles in the series, you can find part one here, part two here and part four here.