PRRS virus in pigs

A mystery swine disease causing reproductive failure and respiratory disease was first described in the late 1980s in North America. A few years later a syndrome with similar clinical signs was observed in Western Europe. During the winter of 1990-91 the disease appeared in Germany and in the Netherlands and since then spread through the rest of Western Europe. 

The virus

In February 1991 the causative agent of porcine reproductive and respiratory syndrome (PRRS) was isolated at the Central Veterinary Institute in the Netherlands.

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Symptoms

The clinical presentation and clinical signs of PRRS varies greatly between herds. Infection with PRRSV shows two different sets of clinical signs: reproductive and respiratory.

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Coinfections

PRRSv has a wide variety of effects on infected animals and populations depending on the virulence of the PRRSv strain, the age and susceptibility of the animals affected, the environment and management practices (vaccines, biosecurity measures, etc. in which they are ...

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Prevalence and strains

In most countries, PRRS is not a notifiable disease and control programs are not in force. Therefore, accurate estimates of the prevalence of infection with wild-type virus in specific countries or regions are not readily available.

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Immunity against PRRSV

In the case of acute viral infections the pathogen is usually cleared from the body by the immune system within 1-2 weeks post inoculation.

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Transmission

Transmission most commonly occurs by close contact between pigs or by exposure to contaminated body fluids (semen, virus-contaminated blood, secretions, contaminated needles, coveralls, and boots).

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Cost of PRRS

Porcine Reproductive and Respiratory Syndrome (PRRS) is a viral disease infecting sows and pigs leading to reproductive failure (abortions, weak and stillborn piglets, infertility), and causes pneumonia and increased mortality in young animals. It is a global problem, ...

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Diagnostic

A significant investment has been made to establish effective prevention, control, and elimination strategies for PRRS. A key part of these strategies has been the development and implementation of reliable, accurate and timely diagnostic procedures.

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Porcine reproductive and respiratory syndrome (PRRS) is a viral disease that causes a decrease in reproductive performance in breeding animals and respiratory disease in pigs of any age. PRRS is the most economically significant disease affecting U.S. swine production.

You are encouraged to use the 5 Step process to PRRS control, developed by Boehringer Ingelheim, to help minimize the impact of PRRS in your herd.
  
Origin  
In the United States, the clinical disease was first discovered and described in 1987–88 in North Carolina, Iowa and Minnesota. PRRS spread rapidly, both in Europe and North America. By the end of 1992, the disease was reported in Canada, Great Britain and several European countries. 

The disease was first described as a syndrome and confused initially with several other diseases. It was referred to as swine mystery disease (SMD) or swine infertility and respiratory syndrome (SIRS), before porcine reproductive and respiratory syndrome (PRRS) became the generally agreed-upon name.

Before the etiological agent causing the disease was known, the syndrome was given various names such as disease 89, pig plague 89, Swine Reproductive and Respiratory Syndrome (SRRS), Swine Infertility and Respiratory Syndrome (SIRS), Porcine Epidemic Abortion and Respiratory Syndrome (PEARS), Blue ear disease, Porcine Reproductive and Respiratory Syndrome (PRRS) (Goyal, 1993). However, at the First International Symposium on SIRS/PRRS held at St. Paul, Minnesota, USA, in 1992, it was decided to name the syndrome Porcine Reproductive and Respiratory Syndrome (PRRS) and its virus Porcine Reproductive and Respiratory Syndrome Virus (PRRSV).
 
Since the PRRS virus is made up of RNA genetic material (instead of DNA), there is a lot of variation in the virus makeup, due to mutations. Two distinct strains, one identified in Europe (Type I) and one identified in the United States (Type II), have been characterized. Both strains can be found globally. Today, PRRSV is endemic in all pork producing countries with both genotypes distributed worldwide.
 
During the past 20 years, we’ve greatly improved our understanding of the PRRS virus and how to control it; however, there is still much to learn. Swine industry consolidation in the past 15 years has led to entire production systems being designed around strategies for controlling or eliminating this disease.