4. Co-Infection of Mycoplasma
hyopneumoniae with
others
Apart
from co-infection of Mhp with viruses or bacteria, there are many
pathogens which comes from the pig farms diet (Michiels et al., 2018).
The presence of mycotoxin in foods and feeds have become a serious
global challenge for animals and humans health not only in the
developing as well as the developed countries(Stoev, 2013). Fumonisin
mycotoxin is a metabolite produced mainly by Fusarium moniliforme
Sheld , which can be subdivided into several subtypes, such as Fumonisin
B1 (FB1), Fumonisin B2(FB2) and Fumonisin B3(FB3). The FB1 is considered to be the
main pathogen for inducing porcine pulmonary edema(Harrison, Colvin,
Greene, Newman, & Cole, 1990) and pulmonary fibrosis that develops in
cases of chronic exposure (Zomborszky-Kovács et al., 2002). Several
groups have studied the interaction between Mhp-infection and
FB1-fed pig, their results revealed a strong oedematous
changes in the interstitium of lung in addition to deteriorated and
extended bronchointerstitial pneumonic process and severe illness
requiring euthanasia observed in one pig and evidence of progressive
pathology in two pigs between study days 44 and 58 by using computed
tomography (CT) and histopathologic review (Posa et al., 2013b; Posa et
al., 2016). Therefore, FB1 aggravated the progression of
infection. On the contrast, Michiels and co-workers indicated that the
pigs which received feed contaminated with the mycotoxin deoxynivalenol
(DON) did not show more severe disease and lesions under experimental
pre-Mhp infection compared to the pigs which were fed with
non-contaminated feed(Michiels et al., 2018). Furthermore, the
opportunistic fungal pathogen Pneumocystis can also be co-infectied with
Mhp, related interstitial pneumonia in both the Pneumocystis positive
lungs and lungs with a mild Mhp infection (Kureljusic,
Weissenbacher-Lang, Nedorost, Stixenberger, & Weissenbock, 2016).
Consequently, the health level of pigs to some extent can be determine
by the kind of feed administered.
Parasitism can also play an important role to negatively impact the
pig’s ability to respond to respiratory pathogens (Tjornehoj, Eriksen,
Aalbaek, & Nansen, 1992). Some adult lungworms that are localized
within the terminal bronchioles do elicit bronchitis, bronchoalveolitis,
alveolar emphysema and atelectasis(Opriessnig, Gimenez-Lirola, et al.,
2011). Furthermore, the pattern of gene expression in the lungs and
draining lymph nodes indicated a local Th2-skewed response induced byAscaris suum , infection with A. suum significantly
compromised the effect of Mhp vaccination (Steenhard et al., 2009),
which indicated that it is necessary to control parasite to provide a
better environment for pig in farms.