Swine Resources - Diseases

July 2020

Pig 333 has interviewed Kristien Van Reeth, professor of virology and swine influenza virus expert. She believes these interesting research findings need much more nuance, and tries to put things in perspective.

A novel swine influenza virus variant has become widespread in swine populations in China since 2016 and has “all the essential hallmarks of a candidate pandemic virus”, according to a recent publication in the journal “Proceedings of the National Academy of Sciences of the US” (PNAS). This swine flu strain has been identified and studied by a team of researchers from the Harbin Veterinary Research Institute, China. They claim that “immediate action is needed to prevent the efficient transmission of this H1N1 swine flu variant to humans”. The PNAS article has received abundant media attention.

March 2020

Feeding Mannan-rich hydrolyzed copra meal and fermented rye to nursery pigs combined with organic acids reduces S. Typh shedding, and feeding fermented rye with OA tends to improve pig performance after S. Typh challenge.

February 2020

For 9 feed ingredients exposed to 30-day shipment conditions, half-lives ranged from 9.6 to 14.2 days, indicating that the feed matrix environment promotes virus stability.

November 2019

Exposure methods: natural, intranasal, intra-tracheal, aerosol or vaccination.

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causative agent of enzootic pneumonia, a chronic respiratory disease that affects mainly growing and finishing pigs. This disease causes significant economic losses on the affected farms by worsening production parameters such as average daily gain and feed conversion rate and by increasing susceptibility to infection by other pathogens as well as medication costs (Thacker and Minion, 2012).

October 2019

In a world where feed ingredients are marketed globally, do we know the minimum infectious dose to transmit the ASF virus in feed? And in water?

Commented article

Niederwerder MC, Stoian A, Rowland R, Dritz SS, Petrovan V, Constance LA, et al.
Infectious Dose of African Swine Fever Virus When Consumed Naturally in Liquid or Feed.
Emerg Infect Dis. 2019;25(5):891-897. https://dx.doi.org/10.3201/eid2505.181495

Comment

The African swine fever epidemic that is affecting Central Europe and Asia never fails to surprise us, especially the apparent ease with which some farms have been infected, including some farms with apparent good biosecurity. This is the case for some of the infected industrial farms in Romania or Bulgaria. The fact that the Romanian Official Veterinary Services considered the water from the Danube river as a likely source of infection of one of these large farms, set all the alarm bells ringing, as reviewing literature there was no data about it.

The present article is interesting, as for the first time it establishes what the minimum infective doses should be in water and feed to generate an ASF infection. That contaminated water or feed can carry the infection should come as no surprise, as we have known for years that feeding pigs with contaminated food has been one of the main routes of ASF infection. But I think it is important not to panic and start to think that any feed or water used in a farm can be infecting material, especially if we consider the experience we have in Spain with the disease. To be better understood, I have allowed myself to perform a few small calculations to see what it is the real probability of reaching infecting concentrations in drinking water. To make it more graphic I have taken the example of the theoretically infected farm from the water taken from the Danube. Does anyone know how many infected dead pigs should fall or be thrown into the Danube to get a dose of 10¹ TCID₅₀? Well, considering the data on the average flow of the Danube: 6500 m³/s and taking into account that the average weight of the pigs thrown into the Danube would be 50 kg and that all the blood present in these (65 ml/ kg weight) was diluted in the water of the Danube and that concentration of virus in blood was the same as detected in cases of an acute infection: 3 x 10⁶ copies/200 microliters (Blome et al., 2013) it would be necessary that every day at least 115 pigs would fell or would be thrown into the river, that all the blood contained in their bodies would be diluted in the drinking water and that this water was not subjected to any disinfection system that could reduce its viral load.

As far as raw materials are concerned and according to the same work, the infectious load should be greater than 10^5.6 TCID₅₀ so it would seem a less likely route if we think of possible contamination in the source fields, but it can be a factor to take into account if the contamination occurs during storage.

When considering the biosecurity of pig farms, taking into account this study, we will need to consider the sanitization of drinking water, especially where it comes from sources that may have some risk (such as rivers or water channels) and in relation to feed, the most important thing will be to ensure that both suppliers and users have safe storage systems that prevent contact of the raw material/ feed with sources of contamination (such as other animals: rodents, birds, wild boar).

May 2019

Depending on the virulence of the strain and the route of exposure, the disease may have four different presentations and early detection can be a challenge due to the lack of specific clinical signs.

April 2019

Based in Sofia, Bulgaria, Huvepharma develops, manufactures and markets human and animal health products.

USDA’s Agricultural Research Service intends to grant to Huvepharma EOOD of Sofia, Bulgaria, an exclusive license for an experimental African swine fever vaccine. The vaccine claim was made in U.S. Patent No. 9,463,234, “Attenuated African swine fever virus strain induces protection against challenge with homologous virulent parental virus Georgia 2007 isolate,” issued on Oct. 11, 2016.

Comments must be received on or before May 22.

The prospective exclusive license will be royalty-bearing. The prospective exclusive license may be granted unless, within 30 days from the date of this published Notice, the ARS receives written evidence and argument which establishes that the grant of the license would not be consistent with the requirements of 35 U.S.C. 209 and 37 CFR 404.7.

Based in Sofia, Huvepharma develops, manufactures and markets human and animal health products. Its products include anticoccidials, veterinary products, feed additives and medicated feed additives. The pharmaceutical company also manufactures and markets enzymes for food, feed and industrial applications.

National Hog Farmer

April 2019

Traditional gilt exposure to seeder animals is being substituted by intratracheal inoculation and aerosol exposure.

Mycoplasma hyopneumoniae is one of the most prevalent and economically significant respiratory pathogens in the swine industry (Maes et al., 2008). Economic losses related to Mycoplasma hyopneumoniae are associated with decreased average daily gain and decreased feed efficiency, and increased medication costs (Maes et al., 2018).

One of the biggest challenges with Mycoplasma hyopneumoniae is that clinical signs and cost can be variable. This variability is primarily due to the stability and shedding status of the sow herd. If the herd is unstable results in sows shedding high numbers to piglets which in turn will result in more severe clinical signs and cost in the finishing phase of production (Fano et al., 2007).

March 2019

( Valentin Panzirsch )

African swine fever (ASF) is the most significant threat to the swine industry worldwide. New research shows the first oral vaccine prototype described for ASF has proven effective on Eurasian wild boars.

February 2019

Although greater concentrations of ASF virus were required to cause infection through feed, the high frequency of exposure may make contaminated feed a more significant risk factor.