Porcine epidemic diarrhea: the return of an old disease

In 2013, 40 years after the first case of porcine epidemic diarrhea (PED) in Europe, PED has emerged in USA that was free of that disease before. The coronavirus, etiological agent of the disease and called PEDV, spread quickly within all the country and in America leading to a significant impact on the pig production. Two types of viral strains have been identified: highly virulent "non-InDel" strains and "InDel" strains because of insertion/deletion in the S gene and associated with less severe clinical cases. PEDV infection causes watery diarrhea and a mortality of up to 100 % in piglets. This review sums up the current knowledge on the virus, its transmission and its worldwide molecular epidemiology, on the physiopathology of the disease and the control measures.En 2013, 40 ans après le premier cas de diarrhée épidémique porcine (DEP) en Europe, la DEP est apparue aux États-Unis jusqu’alors indemne de cette maladie. Le coronavirus responsable de la maladie, le virus de la DEP (PEDV) s’est rapidement propagé dans tout le pays et dans plusieurs pays d’Amérique entraînant un impact significatif sur la production de porcs (perte de 10 % de la production totale aux États-Unis). Deux types de souches ont été identifiés : des souches hautement virulentes dites « non-InDel », et des souches dites « InDel » de part des insertions/délétions dans le gène S et associées à des cas cliniques moins sévères. L’infection par le PEDV provoque l’apparition de diarrhées aqueuses et peut entraîner 100 % de mortalité chez les porcelets nouveau-nés. Cette revue fait le bilan des connaissances actuelles sur le virus, sa transmission et l’épidémiologie moléculaire mondiale, sur la physiopathologie de la maladie et les moyens de contrôle

Lessons learnt from a porcine epidemic diarrhea (PED) case in France in 2014: Descriptive epidemiology and control measures implemented

International audienceAn acute epidemic of porcine epidemic diarrhea (PED) has affected the USA since 2013 and spread all around the world. In France, the immune status of the pig population against PED virus (PEDV) was expected to be low due to the absence of circulation of the virus since the 80's and a compulsory notification of PED was set up in 2014. Here, we reported the first case of a PED outbreak in December 2014 in the North of France after a long absence of the disease, the monitoring of the excretion and the control measure implementation. The isolated strain in France in December 2014 was a PEDV "S-InDel" strain which was close to the "S-InDel" German PEDV strain isolated in May 2014. The individual shedding duration of PEDV in feces was estimated around 20 days for pigs of different ages. Biosecurity measures implemented allowed the limitation of PEDV spread to fattening and farrowing rooms without dissemination to the nursery block. Using strict biosecurity measures, direct shipment of infected fatteners to the slaughterhouse, strict decontamination protocols with a quarantine of 6 weeks for replacement gilts without voluntary contamination helped PEDV fade out within the herd and avoided the spread to other herds. PEDV presence in manure was investigated as well as the inactivation treatment of the virus present in the liquid manure. An increase to a pH 12 of liquid manure by liming led to the absence of PEDV detection by RT-PCR after seven days

Limited shedding of an S-InDel strain of porcine epidemic diarrhea virus (PEDV) in semen and questions regarding the infectivity of the detected virus

International audiencePEDV 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

Phylodynamic analysis of the highly pathogenic avian influenza H5N8 epidemic in France, 2016-2017

In 2016-2017, France experienced a devastating epidemic of highly pathogenic avian influenza (HPAI) H5N8, with more than 400 outbreaks reported in poultry farms. We analyzed the spatiotemporal dynamics of the epidemic using a structured-coalescent-based phylodynamic approach that combined viral genomic data (n = 196; one viral genome per farm) and epidemiological data. In the process, we estimated viral migration rates between departements (French administrative regions) and the temporal dynamics of the effective viral population size (Ne) in each departement. Viral migration rates quantify viral spread between departements and Ne is a population genetic measure of the epidemic size and, in turn, is indicative of the within-departement transmission intensity. We extended the phylodynamic analysis with a generalized linear model to assess the impact of multiple factors-including large-scale preventive culling and live-duck movement bans-on viral migration rates and Ne. We showed that the large-scale culling of ducks that was initiated on 4 January 2017 significantly reduced the viral spread between departements. No relationship was found between the viral spread and duck movements between departements. The within-departement transmission intensity was found to be weakly associated with the intensity of duck movements within departements. Together, these results indicated that the virus spread in short distances, either between adjacent departements or within departements. Results also suggested that the restrictions on duck transport within departements might not have stopped the viral spread completely. Overall, we demonstrated the usefulness of phylodynamics in characterizing the dynamics of a HPAI epidemic and assessing control measures. This method can be adapted to investigate other epidemics of fast-evolving livestock pathogens.ISSN:1865-1674ISSN:1865-168

Fungal protein produced on cassava for growing rats and pigs

This research is a nutritional assessment of a fungal (Aspergillus fumigatus 1-21A) single-cell protein (SCP) that was fed to rats and pigs. The sun-dried biomass resulted from fermentation of either fresh roots or cassava meal substrates and had the following percentage composition: crude protein (N x 6.25), 34.3; ether extract, 3.1; crude fiber, 20.0 ash, 4.3; N-free extract, 27.9; Ca, .20 and P, .79. The gross energy was 4,260 cal/g. An initial biological evaluation based on protein efficiency ratio (PER) and net protein ratio (NPR) methods was conducted using 70 growing rats. Growth responses in rats fed the dried product were similar to those produced by the casein control, provided the biomass was supplemented with DL-methionine. During the growing-finishing period (15.8 to 95.0 kg), pigs were given one of the following experimental diets: 1) control, sorghum + soybean meal (SBM), 2) cassava meal (CM) + SBM + .3% DL-methionine, 3) CM + SCP and 4) CM + SCP + .3% DL-methionine. Diets were calculated to supply 16 and 13% crude protein for the growing (15.8 to 50 kg) and finishing (50 to 95 kg) periods, respectively. The pigs fed the diet based on SCP without any methionine took longer (P<.05) to reach market weight and had poorer (P<.05) feed conversion than pigs fed the other diets. Supplementation with DL-methionine improved (P<.05) the nutritive quality of the fungal protein and the results were comparable to those obtained with diets based on SBM. The use of SCP as a total substitute for SBM did not affect the normal physical condition of the animals