Quantification of the spread of Mycoplasma hyopneumoniae in nursery pigs using transmission experiments

Abstract

Mycoplasma hyopneumoniae (M. hyopneumoniae) is present in almost all swine herds worldwide, but transmission of the pathogen through herds is not yet fully clarified. The aim of this study, performed in 2003, was to investigate and to quantify the transmission of M. hyopneumoniae under experimental conditions by means of an adjusted reproduction ratio (R n ). This R n -value, calculated according to the final size method, expresses the mean number of secondary infections due to one typical infectious piglet during the nursery period. The period lasted from 4 to 10 weeks of age, corresponding with the nursery period used in most European production systems. Additionally, a comparison was made between transmissions of highly virulent and low virulent isolates.Forty-eight weaned piglets, free of M. hyopneumoniae, were housed in six separate pens. During 6 weeks, two animals experimentally infected with M. hyopneumoniae were housed together with six susceptible piglets. At the end of the study, the number of contact-infected animals was determined by the use of nPCR on bronchoalveolar lavage fluid. The R n -values of the highly virulent and the low virulent isolates were estimated to be 1. 47 (0.68-5.38) and 0.85 (0.33-3.39), respectively. No significant difference between the groups was found (P = 0.53). The overall R n was estimated to be 1. 16 (0.94-4.08). Under the present experimental conditions, the transmission of M. hyopneumoniae,

Evaluation of three intervention strategies to reduce the transmission of Salmonella Typhimurium in pigs

“…This ratio expresses the mean number of secondary infections caused by one typically infectious animal in a fully susceptible population during a defined time period (3-14 weeks of age in this study) (Meyns et al, 2004). An Ra value of, for example, 1.76 implies that an infected pig from a group infects, on average, 1.76 pen mates during the observed period.…”

“…This is an important contrast to efficacy studies in which it is susceptibility that is principally tested, and not the combined effect (Springer et al, 2001;Roesler et al, 2004;Tanaka et al, 2010). A similar approach has been used in previous transmission experiments with other pathogens (Laevens et al, 1998;Dewulf et al, 2001;Velthuis et al, 2003;Heres et al, 2004;Meyns et al, 2004).…”

Colonization and Transmission of Methicillin-Resistant Staphylococcus aureus ST398 in Nursery Piglets

“…Two DPI, the seeders were returned to their pens. Transmission was monitored during a period of 6 weeks, corresponding to the nursery period mostly applied under field conditions in Western Europe (15). Swab samples were collected separately from both anterior nares, the skin behind the ears, and the perineum, using a moistened sterile swab.…”

Early Mycoplasma hyopneumoniae infections in European suckling pigs in herds with respiratory problems: detection rate and risk factors

“…The spread of M. hyopneumoniae occurs by either vertical transmission from the sow to the offspring (Sibila et al, 2007) or by horizontal transmission between pigs (Meyns et al, 2004;Fano et al, 2007). Sows transmit M. hyopneumoniae to their offspring mainly by direct nose-to-nose contact, as there is no transmission via the intra-uterine route, nor by colostrum or milk.…”