Location: Food and Feed Safety ResearchTitle: Evidence supporting vertical transmission of Salmonella in dairy cattle Author
|Hanson, Devin - Texas Tech University|
|Loneragan, Guy - Texas Tech University|
|Nisbet, David - Dave|
Submitted to: Epidemiology and Infection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2015
Publication Date: 4/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62753
Citation: Hanson, D.L., Loneragan, G.H., Brown, T.R., Nisbet, D.J., Hume, M.E., Edrington, T.S. 2016. Evidence supporting vertical transmission of Salmonella in dairy cattle. Epidemiology and Infection. 144:962-967.
Interpretive Summary: Dairy calves may contain the bacteria Salmonella, often when they are very young, which can make them sick. Previous research found Salmonella in the feces of dairy calves soon after birth. Samples (various tissues collected throughout the body and lymph nodes) were collected from 20 calves immediately after birth (within minutes) and cultured for Salmonella. Salmonella was recovered from several different tissues in 10 of the 20 calves. Results of this research indicate that Salmonella may be transferred from dam to calf in utero, and will likely change how Salmonella control is approached in young cattle.
Technical Abstract: We set out to investigate whether Salmonella enterica could be recovered from various tissues of viable neonatal calves immediately following parturition. Eleven samples were aseptically collected from each of 20 calves and consisted of both left and right subiliac and prescapular lymph nodes (LN), mesenteric LN, spleen and liver, as well as intestinal tissue (including luminal contents) from the small intestine, caecum, spiral colon and rectum. In addition, a faecal sample was collected from 19 of the dams. Salmonella was recovered from at least one sample from 10 of the 20 neonates. Across all calves, Salmonella was recovered from 12·7% of all samples and from LN in particular, Salmonella was recovered from 10·0%, 5·0%, and 5·0% of subiliac, prescapular, and mesenteric LN, respectively. Within calves, Salmonella was recovered from 0% to 73% of samples and across tissues, estimates of Salmonella prevalence were greatest in the caecum (30%) but was never recovered from the right pre-scapular LN. These data provide evidence of vertical transmission from a dam to her fetus such that viable calves are born already infected and thereby not requiring faecal–oral exposure for transmission. This new knowledge ought to challenge – or at least add to – existing paradigms of Salmonella transmission dynamics within cattle herds.