Summary
Presence and spread of clinically inapparent virus infections in pigs in the German Federal Republic
The occurrence and spread of virus species which, in the Federal Republic of Germany, give rise to forms of disease which are mainly clinically inapparent or in which clinically inapparent infections play a special epizootological role were studied by examination for species‐specific serum antibodies and by direct isolation of the causal agent.
The commonest infections were with ECSO virus (14–100%), Teschen‐Talfan virus (20.1–67.6%), reovirus (38.8–68%), parvovirus (54–92.5%) and pig adenovirus serotype 4 (26.6–74.3%).
A smaller percentage of the sera examined contained antibodies against transmissible gastro‐enteritis (about 3%), human influenza, strain A 2/Hongkong (6.3%) and parainfluenza‐3 (0.16%).
Entirely negative reactions were obtained with pig adenovirus of serotypes 1 to 3, two pig influenza strains (A/swine/Shope; A/swine/Cambridge) and parainfluenza‐1.
Concerning their significance for pig breeding and production, these infections can be put into the following groups:
1. Virus infections which especially interfere with rearing (ECSO, Teschen‐Talfan, reo‐ and adenovirus infections).
2. Virus infections which mainly lead to piglet disease in enzootically infected areas and when introduced into formerly free areas can also cause losses in older animals (transmissible gastro‐enteritis, swine influenza).
3. Virus infections which mainly produce damage in adult animals, e. g. interfere with breeding by producing infertility and damage to embryos (parvovirus infections).
4. Infections in which the pig is not the natural host and is only affected under certain conditions (e. g. the intervention of particularly suited or rare vectors, or massive doses of infective agent) can also produce disease in the pig (infection with parainfluenza virus or human influenza strains).
Résumé
Présence et propagation des infections virales cliniquement inapparentes chez le porc en Allemagne Fédérale
On a examiné chez le porc en Allemagne Fédérale par mise en évidence d'anticorps spécifiques dans le sérum ou par isolation directe de l'agent la présence et la propagation d'espèces virales prédominantes dont le cours clinique n'apparait pas ou dont l'infection clinique non apparente joue un rôle épizootique particulier.
On a mis le plus souvent en évidence des infections à ECSO‐Virus (14–100%), à Teschen‐Talfan‐Virus (20,1–67,6%), à Reovirus (38,8–68%), à Parvovirus (54–92,5%) et à Adenovirus du porc, sérotype 4 (26,6–74,3%).
Un faible pourcentage des sérums examinés ont montré des anticorps de la gastroentérite transmissible (env. 3%), de l'influenza humaine, souche A2/Hongkong (6,3%) et de Parainfluenza‐3 (0,16%). Les animaux ont réagi de façon tout à fait négative avec Adenovirus du porc (sérotypes 1–3), avec 2 souches d'influenza du porc (A/swine/Shope; A/swine/Cambridge) et avec Parainfluenza‐1.
On peut classer les infections sus‐mentionnées en rapport avec leur signification dans l'élevage porcin de la manière suiva...