Severity of bovine tuberculosis is associated with co-infection with common pathogens in wild boar

PLoS One. 2014 Oct 28;9(10):e110123. doi: 10.1371/journal.pone.0110123. eCollection 2014.

Abstract

Co-infections with parasites or viruses drive tuberculosis dynamics in humans, but little is known about their effects in other non-human hosts. This work aims to investigate the relationship between Mycobacterium bovis infection and other pathogens in wild boar (Sus scrofa), a recognized reservoir of bovine tuberculosis (bTB) in Mediterranean ecosystems. For this purpose, it has been assessed whether contacts with common concomitant pathogens are associated with the development of severe bTB lesions in 165 wild boar from mid-western Spain. The presence of bTB lesions affecting only one anatomic location (cervical lymph nodes), or more severe patterns affecting more than one location (mainly cervical lymph nodes and lungs), was assessed in infected animals. In addition, the existence of contacts with other pathogens such as porcine circovirus type 2 (PCV2), Aujeszky's disease virus (ADV), swine influenza virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and Metastrongylus spp, was evaluated by means of serological, microbiological and parasitological techniques. The existence of contacts with a structured community of pathogens in wild boar infected by M. bovis was statistically investigated by null models. Association between this community of pathogens and bTB severity was examined using a Partial Least Squares regression approach. Results showed that adult wild boar infected by M. bovis had contacted with some specific, non-random pathogen combinations. Contact with PCV2, ADV and infection by Metastrongylus spp, was positively correlated to tuberculosis severity. Therefore, measures against these concomitant pathogens such as vaccination or deworming, might be useful in tuberculosis control programmes in the wild boar. However, given the unexpected consequences of altering any community of organisms, further research should evaluate the impact of such measures under controlled conditions. Furthermore, more research including other important pathogens, such as gastro-intestinal nematodes, will be necessary to complete this picture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Coinfection / epidemiology
  • Coinfection / etiology*
  • Geography
  • Lung / pathology
  • Lymph Nodes / pathology
  • Severity of Illness Index
  • Spain
  • Sus scrofa
  • Swine
  • Swine Diseases / diagnosis*
  • Swine Diseases / epidemiology
  • Swine Diseases / microbiology*
  • Tuberculosis, Bovine / diagnosis*
  • Tuberculosis, Bovine / epidemiology
  • Tuberculosis, Bovine / microbiology*

Grants and funding

This study was supported by Ministerio de Ciencia e Innovación (Gobierno de España) PS0900513 and Junta de Extremadura (PDT09A046 and GRU10142). D. Risco has a Formación Profesorado Universitario (FPU) grant from the Ministerio de Ciencia e Innovación (https://sede.educacion.gob.es). E. Serrano was supported by the postdoctoral program (SFRH/BPD/96637/2013) of the Fundação para a Ciência ea Tecnologia, Portugal. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.