RESUMO
Mycoplasma (M.) hyopneumoniae is the initiator agent of the porcine respiratory disease complex (PRDC) and the etiological agent of enzootic pneumonia. M. hyorhinis and M. flocculare are also found in extensive gross pneumonia-like lesions, but their role is not known. We investigated the pathogenicity of M. hyorhinis and M. flocculare in specific-pathogen-free pigs pre-infected or not with M. hyopneumoniae. Mono-inoculated pigs with M. flocculare showed no clinical signs, hematological changes or macroscopic lesions upon necropsy. Mono-inoculated pigs with M. hyorhinis showed, overall seven days after inoculation, an increase in mean temperature with increases in white blood cell (monocyte) counts and in concentrations of pig major acute phase protein, whereas the average daily weight gain (ADWG) decreased compared with non-infected animals. M. hyorhinis was detected in serous membranes (polyserositis) but not in bronchi. Co-infected pigs with M. hyopneumoniae and M. hyorhinis or M. flocculare showed lower ADWG during the third week of the experiment and higher haptoglobin concentrations in contrast to pigs only mono-infected with M. hyopneumoniae. In pigs co-infected with M. hyopneumoniae and M. hyorhinis, it was interesting to observe that (i) M. hyorhinis was detected in bronchi of six pigs, (ii) M. hyopneumoniae was detected in polyserositis and (iii) there was a slight delay in the production of anti-M. hyopneumoniae IgG. The extent of pneumonia was not statistically different between groups. These results suggest that mycoplasmal associations appear to induce an additive effect and increase the inflammatory status in pigs, probably involving in the impairment of the immune system.
Assuntos
Coinfecção/veterinária , Mycoplasma hyopneumoniae/imunologia , Mycoplasma hyorhinis/patogenicidade , Mycoplasma/patogenicidade , Pneumonia Suína Micoplasmática/imunologia , Animais , Anticorpos Antibacterianos/sangue , Brônquios/microbiologia , Coinfecção/microbiologia , Ensaio de Imunoadsorção Enzimática , Haptoglobinas , Pneumonia Suína Micoplasmática/patologia , Organismos Livres de Patógenos Específicos , Suínos , Virulência , Aumento de PesoRESUMO
PEDV is mainly transmitted by the oro-fecal route although PEDV shedding in semen has already been shown for an S-non-InDel PEDV strain infection. The aim of this study was to determine if PEDV can be shed in semen from SPF (specific pathogens free) boars infected by a French S-InDel PEDV strain (PEDV/FR/001/2014) and in case of positive semen to determine the infectivity of that semen. Both infected boars had diarrhea after inoculation and shed virus in feces. PEDV genome was also detected by RT-qPCR in the sperm-rich fraction of semen (6.94 × 103 and 4.73 × 103 genomic copies/mL) from the two boars infected with the S-InDel PEDV strain but only once at 7DPI. In addition, PEDV RNA in Peyer's patches and in mesenteric lymph nodes was also present for the two inoculated boars. The PEDV positive semen (S-non-InDel and S-InDel) sampled during a previous trial and in this boar trial were inoculated to six SPF weaned pigs. The inoculated piglets did not seroconvert and did not shed virus throughout the duration of the study except for one pig at 18 DPI. But, PEDV could be detected in intestinal tissues such as duodenum, jejunum and jejunum Peyer's patches by RT-qPCR except for one pig. Even if PEDV genome has been detected in semen, experimental infection of piglets with positive semen failed to conclude to the infectivity of the detected PEDV.
Assuntos
Infecções por Coronavirus/veterinária , Diarreia/veterinária , Vírus da Diarreia Epidêmica Suína/fisiologia , Doenças dos Suínos/virologia , Animais , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Diarreia/epidemiologia , Diarreia/virologia , Modelos Animais de Doenças , Fezes/virologia , Intestinos/virologia , Masculino , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/imunologia , Vírus da Diarreia Epidêmica Suína/patogenicidade , Sêmen/virologia , Organismos Livres de Patógenos Específicos , Suínos , Doenças dos Suínos/epidemiologia , Eliminação de Partículas ViraisRESUMO
From the severe porcine epidemic diarrhoea (PED) epidemics that struck in 2013 in the United States of America and other countries of North and South America, two types of porcine epidemic diarrhoea virus (PEDV) were isolated, namely the InDel and the non-InDel strains. They are differentiated by insertions/deletions in the S1 nucleotide sequence of the S gene, and differences in virulence were observed from the clinical cases. In 2014, a PED outbreak occurred in a pig farm in France, from which an InDel strain was isolated. This study aimed at comparing, under experimental conditions, the pathogenicity and the direct and indirect transmissions between a non-InDel strain isolated from a PED-affected piglet in 2014 in the USA and the French InDel strain. All infected pigs showed clinical signs with the non-InDel strain although only the inoculated and direct contact pigs showed clinical signs in the InDel strain group. Although viral RNA was detected in air samples with both strains, the indirect contact pigs remained free from infection with the InDel strain in contrast to the non-InDel group in which airborne transmission occurred in the indirect contact pigs. All infected pigs shed virus in faeces regardless of PEDV strain with 9 of 30 pigs showing intermittent faecal shedding. The transmission rate by direct contact was found to be 2.17-fold higher than the non-InDel strain compared with the InDel. In conclusion, the InDel strain was less pathogenic than the non-InDel strain in our experimental conditions. The transmission route differed between the two strains. Direct contact was the main transmission route for the InDel strain, although the non-InDel strain was transmitted through direct contact and indirectly through the air.
Assuntos
Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa/veterinária , Vírus da Diarreia Epidêmica Suína/patogenicidade , Doenças dos Suínos/transmissão , Animais , Sequência de Bases , Infecções por Coronavirus/veterinária , Infecções por Coronavirus/virologia , Diarreia/epidemiologia , Surtos de Doenças/veterinária , Fazendas , Fezes/virologia , França , Vírus da Diarreia Epidêmica Suína/genética , RNA Viral/genética , América do Sul , Suínos , Doenças dos Suínos/virologia , Estados Unidos , VirulênciaRESUMO
In 2013, PED emerged for the first time in the United States (US). The porcine epidemic diarrhea virus (PEDV) spread quickly throughout North America. Infection with PEDV causes watery diarrhea and up to 100% mortality in piglets, particularly for highly pathogenic non-InDel strains circulating in the US. PEDV is mainly transmitted by the fecal-oral route. Transmission via the venereal route has been suspected but not previously investigated. The aim of the study was to determine if PEDV could be detected in semen from infected specific pathogen-free (SPF) boars inoculated with a PEDV US non-InDel strain suggesting venereal transmission may occur. Two boars orally inoculated with PEDV showed clinical signs and virus shedding in feces. Transient presence of the PEDV genome was detected by RT-qPCR in the seminal (5.06 × 102 to 2.44 × 103 genomic copies/mL) and sperm-rich fraction of semen (5.64 × 102 to 3.40 × 104 genomic copies/mL) and a longer duration of viral shedding was observed in the sperm-rich fraction. The evidence of PEDV shedding in semen raises new questions in term of disease spread within the pig population with the use of potentially contaminated semen.