Article

Association of severity of enteric granulomatous inflammation with disseminated Mycobacterium avium subspecies paratuberculosis infection and antemortem test results for paratuberculosis in dairy cows

College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1681, USA.
Veterinary Microbiology (Impact Factor: 2.73). 04/2008; 131(1-2):154-63. DOI: 10.1016/j.vetmic.2008.02.017
Source: PubMed

ABSTRACT Disseminated infection (DI) of Mycobacterium avium subspecies paratuberculosis (MAP) in cattle may impair cow health, potentiate spread of disease, and is a potential food-safety risk. The objectives of this study were to determine the association between severity of histologic enteric lesions and the occurrence of DI, clinical signs, and positive fecal culture and serum ELISA results. Bacteriologic fecal culture and serum ELISA were performed on 40 dairy cows from MAP-infected herds. Cows were classified as having DI if MAP was isolated from any of 11 extra-intestinal tissues collected postmortem. A grade of 0-3, corresponding to the severity of histologically evident granulomatous inflammation was determined for sections of ileum, jejunum, mesenteric lymph node, and ileocolic lymph node. An overall intestinal inflammation (OII) grade of 0-3 was assigned to each cow. The proportion of cows with DI increased with tissue-specific lesion grade and OII grade. All cows with grade 3 inflammation in any single tissue had DI, however, some cows with DI had grade 1 inflammation or no lesions. In general, there was a positive association between OII grade and clinical signs, gross enteric lesions, and positive ELISA and fecal culture results. However, 12% of OII grade 0 cows had clinical signs (explained by other conditions recognized with necropsy), and the proportion of positive ELISA results was lower for OII grade 3 cows relative to grade 2 cows. Although MAP dissemination may occur early in the disease process, histopathology of intestinal tissues may be used to detect a substantial proportion of DI cows.

0 Followers
 · 
102 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Paratuberculosis is a widespread disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). For long time the infection has been believed as confined to the intestine. Disseminated infection in ruminants with MAP has gained more interest in recent years. In this study the histological lesions, the distribution of MAP in intestinal and mammary tissues of seropositive sheep and the sensitivity of direct diagnostic tests are evaluated. Histopathological lesions were observed in the proximal jejunum, distal jejunum and ileum of 19 sheep. Types 3b and 3c lesions were observed. Sheep with subclinical infection had type 3c ileal lesions, while clinically infected animals had mainly type 3b ileal lesions (p < 0.05). Ziehl–Neelsen (ZN) staining was more sensitive for detecting acid-fast bacilli in type 3b intestinal lesions than in type 3c (p < 0.05). Immunohistochemistry (IHC) was more sensitive than ZN staining in detecting infected intestinal samples (p < 0.05). PCR was the most sensitive technique in detecting MAP in both intestinal and extra-intestinal samples (p < 0.05). MAP was mainly observed in mammary tissues of sheep with type 3b intestinal lesions, although these findings were not statistically significant (p > 0.05). The number of MAP in the intestine might influence the clinical course and the local histopathological lesions, but probably further factors contribute to the discrimination between local and general infection.
    Small Ruminant Research 06/2012; 105(1-3):295-299. DOI:10.1016/j.smallrumres.2011.11.015 · 1.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The infection biology of Mycobacterium avium subspecies paratuberculosis (MAP) has recently crystalized with added details surrounding intestinal invasion. The involvement of pathogen-derived effector proteins such as the major membrane protein, oxidoreductase and fibronectin attachment proteins have been uncovered. Mutations constructed in this pathogen have also shed light on genes needed for invasion. The host cell types that are susceptible to invasion have been defined along with their transcriptional response. Recent details have given a new appreciation for the dynamic interplay between the host and bacterium that occurs at the outset of infection. An initial look at the global expression pathways of the host has shown a circumvention of the cell communication pathway by MAP, which loosens the integrity of the tight junctions. We now know that MAP activates the epithelial layer and also actively recruits macrophages to the site of infection. These notable findings are summarized along with added mechanistic details of the early infection model. We conclude by proposing critical next steps to further elucidate the process of MAP invasion.
    Infection and immunity 08/2013; DOI:10.1128/IAI.00575-13 · 4.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enzootic pneumonia (EP) caused by Mycoplasma hyopneumoniae has a significant economic impact on domestic pig production. A control program carried out from 1999 to 2003 successfully reduced disease occurrence in domestic pigs in Switzerland, but recurrent outbreaks suggested a potential role of free-ranging wild boar (Sus scrofa) as a source of re-infection. Since little is known on the epidemiology of EP in wild boar populations, our aims were: (1) to estimate the prevalence of M. hyopneumoniae infections in wild boar in Switzerland; (2) to identify risk factors for infection in wild boar; and (3) to assess whether infection in wild boar is associated with the same gross and microscopic lesions typical of EP in domestic pigs. Nasal swabs, bronchial swabs and lung samples were collected from 978 wild boar from five study areas in Switzerland between October 2011 and May 2013. Swabs were analyzed by qualitative real time PCR and a histopathological study was conducted on lung tissues. Risk factor analysis was performed using multivariable logistic regression modeling. Overall prevalence in nasal swabs was 26.2% (95% CI 23.3-29.3%) but significant geographical differences were observed. Wild boar density, occurrence of EP outbreaks in domestic pigs and young age were identified as risk factors for infection. There was a significant association between infection and lesions consistent with EP in domestic pigs. We have concluded that M. hyopneumoniae is widespread in the Swiss wild boar population, that the same risk factors for infection of domestic pigs also act as risk factors for infection of wild boar, and that infected wild boar develop lesions similar to those found in domestic pigs. However, based on our data and the outbreak pattern in domestic pigs, we propose that spillover from domestic pigs to wild boar is more likely than transmission from wild boar to pigs.
    PLoS ONE 03/2015; 10(3):e0119060. DOI:10.1371/journal.pone.0119060 · 3.53 Impact Factor

Full-text (3 Sources)

Download
134 Downloads
Available from
May 19, 2014