Present today in most pig-producing countries, Piglet Wasting Disease (PAD) appeared in parallel in North America and Europe from 1996.
Affecting piglets aged 7 to 15 weeks, the animal disease manifests itself in the form of fevers and loss of appetite. These signs are accompanied by breathing difficulties and sometimes diarrhoea, all of which lead, in severe cases, to the animal wasting away (loss of weight) and sometimes to death. The onset of severe forms of the disease varies considerably, both between farms and between animals within the same farm.
In sick animals, lesions are observed in different organs (lung, liver, kidney, lymph nodes, etc.). Viral research undertaken on the tissues of injured organs has revealed the presence of a virus widely distributed within the world pig population, circovirus type 2 (PCV 2). To date, and this following more than ten years of research, only suids (pigs and wild boar) and birds have been identified as hosts of circoviruses. They have never been found in humans.
All circoviruses are associated with pathologies that affect the immune system by causing a drop in the number of lymphocytes (variety of white blood cells involved in the immune response) in their hosts. However, many animals can be infected without showing clinical signs.
If this virus is considered today as one of the major causes associated with PAD, its mere presence within a farm is not enough to trigger the disease. Other environmental factors also play a role in the expression of MAP within farms.
The impact of piglet wasting disease has been considerably reduced in France for several years thanks to the implementation of measures mainly related to breeding techniques (improvement of hygiene conditions, reduction of stress situations for animals ).
ANSES’s activities relating to piglet wasting disease
The ANSES laboratory in Ploufragan conducts research activities on this disease, in particular to understand the role of sow vaccination (parvovirus/red mullet vaccination) on the development of MAP in her offspring as well as the dynamics of the circulation of PCV2 in breeding.
The lab is also conducting research on the virus (PCV2) himself:
- development of a method for quantification of the virus genome in real time;
- characterization in vitro et live an infectious PCV2 clone;
- implementation of tests aimed at identifying non-infectious cofactors that can promote infection by the circovirus (immunostimulation of piglets infected with PCV2);
- study of the role of PCV2 in MAP by a method using DNA chips;
- study of PCV2 virulence factors by introducing a mutation into the virus capsid protein gene.
