Experimental Neurology By Prof Paul Glees Pp xii + 532 (Oxford: Clarendon Press; London: Oxford University Press, 1961) 75s net

The Nervous System

We propose the creation of seven new species in the genus Pestivirus (family Flaviviridae) in addition to the four existing species, and naming species in a host-independent manner using the format Pestivirus X. Only the virus species names would change; virus isolates would still be referred to by their original names. The original species would be re-designated as Pestivirus A (original designation B ovine viral diarrhea virus 1), Pestivirus B (Bovine viral diarrhea virus 2), Pestivirus C (Classical swine fever virus) and Pestivirus D (Border disease virus). The seven new species (and example isolates) would be Pestivirus E (pronghorn pestivirus), Pestivirus F (Bungowannah virus), Pestivirus G (giraffe pestivirus), Pestivirus H (Hobi-like pestivirus), Pestivirus I (Aydin-like pestivirus), Pestivirus J (rat pestivirus) and Pestivirus K (atypical porcine pestivirus). A bat-derived virus and pestiviruses identified from sheep and goat (Tunisian sheep pestiviruses), which lack complete coding region sequences, may represent two additional species.

Proposed revision to the taxonomy of the genus Pestivirus, family Flaviviridae.

Bovine viral diarrhea virus (BVDV) is a globally-distributed agent responsible for numerous clinical syndromes that lead to major economic losses. Two species, BVDV-1 and BVDV-2, discriminated on the basis of genetic and antigenic differences, are classified in the genus Pestivirus within the Flaviviridae family and distributed on all of the continents. BVDV-1 can be segregated into at least twenty-one subgenotypes (1a-1u), while four subgenotypes have been described for BVDV-2 (2a-2d). With respect to published sequences, the number of virus isolates described for BVDV-1 (88.2%) is considerably higher than for BVDV-2 (11.8%). The most frequently-reported BVDV-1 subgenotype are 1b, followed by 1a and 1c. The highest number of various BVDV subgenotypes has been documented in European countries, indicating greater genetic diversity of the virus on this continent. Current segregation of BVDV field isolates and the designation of subgenotypes are not harmonized. While the species BVDV-1 and BVDV-2 can be clearly differentiated independently from the portion of the genome being compared, analysis of different genomic regions can result in inconsistent assignment of some BVDV isolates to defined subgenotypes. To avoid non-conformities the authors recommend the development of a harmonized system for subdivision of BVDV isolates into defined subgenotypes.

Variability and Global Distribution of Subgenotypes of Bovine Viral Diarrhea Virus

In 2013, several Austrian piglet-producing farms recorded outbreaks of action-related repetitive myoclonia in newborn piglets ("shaking piglets"). Malnutrition was seen in numerous piglets as a complication of this tremor syndrome. Overall piglet mortality was increased and the number of weaned piglets per sow decreased by more than 10% due to this outbreak. Histological examination of the CNS of affected piglets revealed moderate hypomyelination of the white substance in cerebellum and spinal cord. We detected a recently discovered pestivirus, termed atypical porcine pestivirus (APPV) in all these cases by RT-PCR. A genomic sequence and seven partial sequences were determined and revealed a 90% identity to the US APPV sequences and 92% identity to German sequences. In confirmation with previous reports, APPV genomes were identified in different body fluids and tissues including the CNS of diseased piglets. APPV could be isolated from a "shaking piglet", which was incapable of consuming colostrum, and passaged on different porcine cells at very low titers. To assess the antibody response a blocking ELISA was developed targeting NS3. APPV specific antibodies were identified in sows and in PCR positive piglets affected by congenital tremor (CT). APPV genomes were detected continuously in piglets that gradually recovered from CT, while the antibody titers decreased over a 12-week interval, pointing towards maternally transmitted antibodies. High viral loads were detectable by qRT-PCR in saliva and semen of infected young adults indicating a persistent infection.

/pdf/congenital-infection-with-atypical-porcine-pestivirus-appv-1yb384crqx.pdf

Congenital infection with atypical porcine pestivirus (APPV) is associated with disease and viral persistence.

Congenital tremor type A-II in piglets has been regarded as a transmissible disease since the 1970s, possibly caused by a very recently-described virus: atypical porcine pestivirus (APPV). Here, we describe several strains of APPV in piglets with clinical signs of congenital tremor (10 of 10 farms tested). Piglets on a farm with no history of congenital tremor were PCR-negative for the virus. To demonstrate a causal relationship between APPV and disease, three gilts were inoculated via intramuscular injection at day 32 of pregnancy. In two of the three litters, vertical transmission of the virus occurred. Clinical signs of congenital tremor were observed in APPV-infected newborns, yet also two asymptomatic carriers were among the offspring. Piglets of one litter were PCR-negative for the virus, and these piglets were all without congenital tremors. Long-term follow up of farm piglets born with congenital tremors showed that the initially high viremia in serum declines at five months of age, but shedding of the virus in feces continues, which explains why the virus remains present at affected farms and causes new outbreaks. We conclude that trans-placental transmission of APPV and subsequent infection of the fetuses is a very likely cause of congenital tremor type A-II in piglets.

https://www.mdpi.com/1999-4915/8/10/271/pdf

Atypical Porcine Pestivirus: A Possible Cause of Congenital Tremor Type A‐II in Newborn Piglets

Pestiviruses are highly variable RNA viruses belonging to the continuously growing family Flaviviridae. A genetically very distinct pestivirus was recently discovered in the USA, designated atypical porcine pestivirus (APPV). Here, a screening of 369 sera from apparently healthy adult pigs demonstrated the existence of APPV in Germany with an estimated individual prevalence of 2.4% and ~10% at farm level. Additionally, APPV genomes were detected in newborn piglets affected by congenital tremor (CT), but genomes were absent in unaffected piglets. High loads of genomes were identified in glandular epithelial cells, follicular centers of lymphoid organs, the inner granular cell layer of the cerebellum, as well as in the trigeminal and spinal ganglia. Retrospective analysis of cerebellum samples from 2007 demonstrated that APPV can be found in piglets with CT of unsolved aetiology. Determination of the first European APPV complete polyprotein coding sequence revealed 88.2% nucleotide identity to the APPV sequence from the USA. APPV sequences derived from different regions in Germany demonstrated to be highly variable. Taken together, the results of this study strongly suggest that the presence of APPV genomes in newborn piglets correlates with CT, while no association with clinical disease could be observed in viremic adult pigs.

/pdf/presence-of-atypical-porcine-pestivirus-appv-genomes-in-45qk7p2mht.pdf

Presence of atypical porcine pestivirus (APPV) genomes in newborn piglets correlates with congenital tremor

Im Dezember 2017 kam es in einem Bullenmastbetrieb mit Fresseraufzucht in
 Westdeutschland innerhalb eines Tages plotzlich zu einem Ruckgang der
 Futteraufnahme bei ansonsten zunachst ungestortem Allgemeinbefinden der Tiere.
 Die reduzierte Futteraufnahme war am darauffolgenden Tag noch ausgepragter;
 zudem zeigten einige Tiere eine Pansentympanie mit dorsaler Gasblase, die eine
 Behandlung erforderte. Als mogliche Ursache kam die Maissilage infrage, die seit
 dem Tag der reduzierten Futteraufnahme aus einem anderen Silobereich entnommen
 wurde als zuvor. Diese Maissilage-Partie stammte von einer Ackerflache, auf der
 in einem gewassernahen Teilbereich ubliche Pflanzenschutzmasnahmen nicht erfolgt
 waren und die zudem stark von Windschaden betroffen war (viele abgeknickte
 Maispflanzen). Nur auf diesem Areal wuchs Gewohnlicher Stechapfel, dessen
 Fruchte und Samen in den inkriminierten Maissilageproben nachgewiesen wurden.
 Nach einem Austausch der Maissilage gegen nicht kontaminiertes Material und
 einer Behandlung der von einer Tympanie betroffenen Tiere mit einem
 Antitympanikum sowie einem Lebendhefe-Praparat erholten sich die Bullen
 innerhalb von 6 Tagen. Ursachlich fur diese auffallige Symptomatik waren
 vermutlich die antinutritiven Inhaltsstoffe von Datura stramonium, die
 nachgewiesenermasen die Magen-Darm-Motorik beeintrachtigen konnen.

Feed refusal in fattening bulls because of maize silage contamination by Jimson weed (Datura stramonium).

Multiple diagnostic procedures, their results and interpretation in a case with severe lameness in fattening pigs are described. It is shown that selected diagnostic steps lead to identification of various risk factors for disease development in the affected herd. One focus of this case report is the prioritization of diagnostic steps to verify the impact of the different conditions, which finally led to the clinical disorder. Assessing a sufficient dietary phosphorus (P) supply and its impact on disease development proved most difficult. The diagnostic approach based on estimated calculation of phosphorus intake is presented in detail. On a farrow-to-finishing farm, lameness occurred in pigs with 30–70 kg body weight. Necropsy of three diseased pigs revealed claw lesions and alterations at the knee and elbow joints. Histologic findings were characteristic of osteochondrosis. All pigs were positively tested for Mycoplasma hyosynoviae in affected joints. P values in blood did not indicate a P deficiency, while bone ashing in one of three animals resulted in a level indicating an insufficient mineral supply. Analysis of diet composition revealed a low phosphorus content in two diets, which might have led to a marginal P supply in individuals with high average daily gains with respect to development of bone mass and connective tissue prior to presentation of affected animals. Finally, the impact of dietary factors for disease development could not be evidenced in all submitted animals in this case. Mycoplasma (M.) hyosynoviae was identified to be an important etiologic factor for disease. Other, non-infectious factors, such as osteochondrosis and claw lesions might have favored development of lameness. In addition, a relevant marginal P supply for pigs was found in a limited time period in a phase of intense growing, but the potential interaction with infection by M. hyosynoviae is unknown. The presented case of severe lameness in fattening pigs revealed that three different influences presumably act in pathogenesis. Focusing only on one factor and ignoring others might be misleading regarding subsequent decision-making for prevention and therapy. Finally, clinical symptoms disappeared after some changes in diet composition and anti-inflammatory treatment of individual animals.

/pdf/lameness-in-fattening-pigs-mycoplasma-hyosynoviae-4vrrmqfaak.pdf

Lameness in fattening pigs – Mycoplasma hyosynoviae, osteochondropathy and reduced dietary phosphorus level as three influencing factors: a case report

Jörg Tenhündfeld

Papers

Presence of atypical porcine pestivirus (APPV) genomes in newborn piglets correlates with congenital tremor

Feed refusal in fattening bulls because of maize silage contamination by Jimson weed (Datura stramonium).

Lameness in fattening pigs – Mycoplasma hyosynoviae, osteochondropathy and reduced dietary phosphorus level as three influencing factors: a case report