Consequences pathologiques d'un episode grippal severe (virus swine A/H1N1 dans les conditions naturelles chez la truie non immune en debut de gestation

Abstract

Pathological consequences of a severe outbreak of swine influenza (H1N1 virus) in the non immune sow at the beginning of pregnancy, under natural conditions. A sudden acute outbreak of fever, depression, anorexia and coughing in a group of nulliparous sows from a herd that was currently under epidemiological investigation lead to build a particular disposal of observation. The clinical signs were daily recorded including rectal temperature. Blood was taken from the sows at the beginning of the troubles and 3 weeks later for the detection of Aujesky's disease, coronavirus TGE-like, Influenza viruses A/H1N1 and A/H3N2 and Mycoplasma hyopneumoniae. Viral detection was attempted from nasal swabs and aborted fetuses during the acute phase. The clinical study showed fever reaching near 41 degrees C on most of the pigs and lasting usually from 2 to 5 days. The diagnosis of Influenza (virus swine H1N1) was established both on serology (massive seroconversion) and on the detection of the virus from the nasal swabs and from an aborted fetus. The control of the lungs of sows "not in pig" and culled showed extended lesions of bronchopneumonia and Pasteurella multocida was found. The technical consequences of this severe outbreak of Influenza on reproduction were mainly important at the beginning of pregnancy. Over 13 sows inseminated less than 1 week before the outbreak, only 3 farrowed (respectively 5.5 and 12 piglets); 7 returned to oestrus and 3 "not a pig" at 21 days (echotomography) did not show signs of heat and were culled. Over 8 pregnant sows (1 month of pregnancy), 6 farrowed normal litters and total embryonic resorption occurred in 2 sows. Over 18 pregnant sows (more than 45 days gestation) one aborted.

The influence of experimental infection of gilts with swine H1N2 influenza A virus during the second month of gestation on the course of pregnancy, reproduction parameters and clinical status

“…Among different infectious agents causing reproductive disorders in pigs, viral infections of pregnant gilts and sows result in the biggest economic losses [8,12]. According to the results obtained previously [5,6,10,11] the influenza virus, in addition to respiratory symptoms can cause abortions and other reproduction disorders in both humans and animals, including pigs. Abortions observed during influenza infection may be a result of high fever and proinflammatory cytokines as well as transplacental transmission of the virus [4,5,13].…”

“…Abortions in IAV infected individuals (humans, pigs) may be a consequence of high fever and pro-inflammatory cytokines as well as transplacental transmission of the virus, what was confirmed for other influenza viruses [5,13]. Both animal and human epidemiologic studies suggest that hyperthermia is often associated with an increased risk for adverse outcomes [14,15].…”

Skeletal and neurological malformations in pigs congenitally infected with Menangle virus

“…Several viruses are capable of causing embryonic and foetal death in pigs as part of the syndrome of stillbirths, mummification, embryonic death and infertility (SMEDI). The most important of these throughout the world are porcine parvovirus (PPV), 1,2 Lelystad (porcine reproductive and respiratory syndrome) virus (PRRS), 3,4 classical swine fever virus (CSFV), 5,6 Aujeszky's disease (pseudorabies) virus (ADV), 7,8 swine influenza virus (SIV) 9 and encephalomyocarditis virus (EMCV) 10,11 . Other porcine viruses are of regional importance.…”

Reproductive disease and congenital malformations caused by Menangle virus in pigs

“…6 JEV has been associated with reproductive disease in pigs in Japan. 7 There are several other viruses exotic to Australia that can cause reproductive disease: CSFV, 8,9 ADV, 10 SIV, 11 Lelystad (PRRS) virus 12 and LPMV (Mexican blue eye paramyxovirus). 13 Of these, only JEV, 7,14 CSFV 8,15 and SIV 16 induce congenital malformations.…”