Science Page: Comparison of individual oral fluids, pooled oral fluids and Swiffer™ environmental samples of drinkers for the detection of influenza A virus and PRRS virus by PCR

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week,  we are sharing a study done by Taylor Homann, a DVM student at the University of Minnesota in collaboration with the Swine Vet Center and Boehringer Ingelheim, regarding the comparison of several sample types to detect PRRS and flu by PCR.

Key points:

  • Pooling oral fluid samples seems to be a good strategy to determine the status of a farm (positive/negative) for influenza A virus (IAV) and PRRSV.
  • Sampling water cups using environmental Swiffer™ samples appears to be a sensitive approach to detect IAV at the pen level.
  • However, sample size has been limited to one farm.

Objective:

The objective of this project was to compare the sensitivity of pooled pen oral fluids (OF) and environmental samples (Swiffer™ kits on water cups) using individual pen oral fluids as the standard.

Methods:

Fifteen paired environmental and individual pen OF were collected at days 3, 7, 10, 17, 24 and 31 post placement in two different nursery farms. Environmental samples (ES) were taken using Swiffer™ cloths to sample the bottom of water cups (both pans and bowls), focusing around nipples. After individual samples were collected, pen OF were pooled by 3.

Results:

There was an overall sensitivity of 71% (IAV) and 14% (PRRS) for the ES samples compared to individual OF. Pooled oral fluids samples had an overall sensitivity of 50%(IAV)and 80%(PRRSV)relative to individual pen OF.

Homann PRRS flu Oral fluid water cup sample comparison

In summary, ES appears to be a good strategy when sampling for IAV and not a reliable option when trying to diagnose PRRSV.

Mycoplasma hyorhinis prevalence varies based on pigs’ age

Summary

  • Mycoplasma hyorhinis can cause polyserositis and arthritis in post-weaning pigs.
  • To study M.hyorhinis‘ prevalence based on age, nasal swabs were taken from pigs at 1, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70 and 77 days as well as from sows, in 3 different Minnesotan herds (A, B, and C).
  • 8.8% of the sows were positive for M.hyorhinis in herds A and B whereas 3.3% of the sows were positive in herd C.
  • The percentage of positive piglets (<21 days of age) was low: between 0 and 10% depending on the herds.
  • At 28 days of age, the prevalence of M.hyorhinis in pigs increased dramatically to around 50% in herd A and 100% in herd B. After 42 days of age, the prevalence in those herds stayed above 95%.
  • The prevalence in herd C stayed close to 0% until the pigs reached the age of 77 days, time at which the prevalence increased to 100%.

Did you see our Science page on Mycoplasma hyorhinis and swine conjunctivitis?

Mhyorhinis prevalence baed on age Rovira 2017

Abstract

Mycoplasma hyorhinis is one of the causative agents of polyserositis and arthritis in postweaning pigs. Knowledge regarding colonization frequency and age distribution in modern pig production is lacking. The objective of this study was to estimate the prevalence of M hyorhinis colonization in different age groups across three commercial pig populations. Nasal swabs were collected from sows, piglets and nursery pigs of different ages. Oral fluids were collected from nursery pigs. Necropsies were performed to assess the presence of M hyorhinis-associated disease. M hyorhinis was detected in 5/60 sows in herd A, 3/60 in herd B and none in herd C. In herd A and B, the prevalence was low in preweaning piglets (∼8 per cent) and high in postweaning pigs (∼98 per cent). A total of 7/8 oral fluids tested PCR positive in herds A and B, while 1/8 tested positive in herd C. In herd C, the preweaning and postweaning prevalence was low. In herds A and B, necropsied pigs had polyserositis lesions where M hyorhinis was detected by PCR. This study showed that prevalence of M hyorhinis colonization varies with pig age and across farms. Information generated will aid in the design and implementation of control and prevention strategies.

Link to the full paper