Articles - Pig health

In high-density swine regions of North America, air filtration is playing an important role in the effort to maintain PRRS free commercial sow herds

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.

Oral fluid samples can at times replace traditional blood testing while requiring less labor and technical skill. Also there is clearly reduced stress for people and pigs, which is becoming important in modern food animal production.

Here we present a table of differential diagnosis of the most common diarrheas during lactation.

Rotaviruses are important enteric pathogens that affect newborns of several animal species. In swine, they can cause gastroenteritis in piglets.

Although pigs can be infected with different species of coccidia, in suckling piglets the most important disease caused by enteric protozoa is coccidiosis due to Isospora suis.

The genus Clostridium includes numerous species of anerobic bacteria with large rod-shaped forms, spore makers, and producers of extremely potent and diverse toxins that are almost always responsible for the diseases they cause.

Escherichia coli is an enterobacteria that forms part of the normal intestinal microbiota of healthy animals. Usually, E. coli present in animals are communal antipathogenic strains and they even play a beneficial role, since they compete in several ways with the pathogenic strains in the ecological niche of the lumen.

Available data indicate that PCV2 has the ability to modulate the immune response, not only during the obvious overt disease but also in a subclinically infection.

One issue is to overcome maternal immunity, which is true for all PCV2 vaccines in the market, and another is whether the most from these vaccines is achieved independently of the PCV2 antibody titre at vaccination

Basic preventative measures of management should be included in the control of the disease, such as adequate temperature control of the barns, a complete all-in all-out hygiene and disinfection, and the avoidance of any mixing of animals from distinct sanitary origins.

The decrease in the contact time between the mother and her piglets, due to the common practice of early weaning, has led to the appearance of some piglets that are not completely colonised or that have not acquired a sufficient level of maternal antibodies. On mixing with other litters, these piglets are faced with distinct strains while lacking the necessary antibodies against the disease.

It is important to be able to identify the distinct circulating strains and to differentiate between the strains that are merely colonisers and those that have the capacity to produce disease. With this aim various methods of classification of strains or “typing” of H. parasuis have been developed.

When the clinical signs on the farm and the lesions observed in the piglets lead us to suspect that there is a Haemophilus parasuis infection we have to confirm this diagnosis in the laboratory

Haemophilus parasuis is present in all swine producing countries and its prevalence is close to 100% on conventional farms. However, only a percentage of these farms present pathologies associated to the infection.

The factors of virulence allow the pathogenic strains to survive inside the animal and cause the infection, while the non-virulent strains lack these factors and can only survive in the upper respiratory tract as colonisers.

On a conventional farm with no problems with Glässer’s disease, it is possible to isolate various strains of Haemophilus parasuis which colonise piglets while being in balance with the animal’s immunity without producing pathology.

H. parasuis is a gram-negative bacillus of small size, which belongs to the Pasteurellaceae family. The group characterized by fibrinous polyserositis and fibrinous arthritis became known as Glässer’s disease.

We may have some highly efficient vaccines, but we shouldn’t forget that for their application we must obtain good diagnostic information, and that in all cases we should not lose sight of good management and a good control of the concomitant diseases.

Between 1995 and 1997, at the beginning of an epizootic called “maladie de l’amagrissement du porcelet” (MAP), it was observed that the farms that were most affected and that had the most losses, generally presented obvious deviations from what we would consider to be a suitable management of the animals and facilities. This is why Dr. François Madec made a list of management practices with the aim of improving the anomalous situation observed.

The use of diagnostics will allow producers and practitioners to work together towards the common goal of PRRS eradication

Preventing vertical and horizontal spread of PRRSV from dam to offspring is critical for the production of naive replacement stock