Page 3 of articles about influenza in Articles

The high seroprevalences found supports the feeling you get in the field that PCV2, PRRSV, and SIV are very widespread viruses in our farms.

As the Influenza A virus ecology has become more complex due to viral reassortment and mutation, so have the sample types and diagnostic tests available for detecting or diagnosing influenza infections in swine.

Four virus lineages, having clearly distinguishable HA, are currently co-circulating in European pigs and can be considered as enzootic viruses, even if their relative prevalence and level of incidence vary from one country to another.

After the clinical and serological evaluation it is decided to vaccinate against PRRSV, with which we achieve a gradual improvement in the health status on the farm. Some months later, a severe cough appears in the fattening pigs that later also appears in the nursery and in the sows.

This farm produces its own gilts from grandmother sows, but taking advantage of the adaptation to meet the needs of the welfare law it was decided to increase its capacity from 600 sows to 1,200.

PRRSV by itself may induce mild-to-severe respiratory disease but rarely results in mortality.

A cough outbreak appeared in 8-9 weeks old piglets. It apparently was a "normal" outbreak that could be solved with a few days of antibiotic but the pigs did not respond to the treatment.

In July 2010 a severe respiratory disease occurred in the farm: coughing in gilts, and coughing and depression in fatteners concomitantly to an increase of the mean stillborn and mummified piglet rate in a batch of sows.

Over the last several years, new sampling, monitoring and diagnostic tools for the swine industry that are faster, simpler and more cost effective have been developed and validated. One of these techniques is the sampling and use of oral fluids (saliva) as specimens for diagnostics in swine.

Abortions are not always witnessed in yards or extensive systems. Evidence is provided by sudden weight loss and a vulval discharge.

Most of the outbreaks detected in pigs have resulted from infections transmitted to the pigs by humans or have no known cause.

Normally, in pigs influenza is an acute respiratory infection with pyrexia, lethargy, prostration, reluctance to eat and drink. Indoor housed pigs are usually affected simultaneously, with recovery within 1-2 weeks. No adverse effects occur unless there is secondary infection.

Pig rearing practices in the country need a lot of improvement considering that about 70% of pigs are on a backyard level.

The usual pig viruses are H1N1, H3N2 and H1N2. The original H1N1 pig viruses have been largely replaced by poultry viruses in pigs. The H3N2 viruses were from humans originally. The H1N2 viruses are re-assortants from human viruses (H and N genes) and poultry viruses.

The first swine influenza viruses were all H1N1 and were for about 60 years in North America. In the middle 1980’s, there appeared in European pigs H3N2 viruses that were derived originally from humans and had adapted to pigs and were therefore known as human-like H3N2 viruses. These viruses have since appeared in other parts of the world most notably as H3N2 in the USA in 1998. These viruses however contained bits of human, avian and swine viruses and were therefore called triple re-assortants.

It is produced by a virus with genetic material from porcine, human and avian viruses which has shown the ability unusually for such a virus to transmit from human to human. The virus appears to have 2 of 8 gene segments that derive from eurasian swine viruses. The NA and matrix genes of the new virus have not been seen in humans or pigs before.