Ivan Vrbanac

Experimental model of enterotoxigenic Escherichia coli infection in pigs: potential for an early recognition of colibacillosis by monitoring of behavior

The hypothesis that altered behavior is a sign for an early recognition of disease was tested. The experiment was conducted to evaluate the behavioral patterns of pigs in a model of postweaning colibacillosis. Twenty-five weaned pigs (from a herd that was previously found to be highly susceptible to F4+ Escherichia coli strains) were randomly assigned into 5 groups, kept in isolated pens under the controlled ambiental conditions. One day after weaning, the pigs from three groups were intragastrically inoculated (via orogastric tube) with either F4ac+ (1466 or 2407) or F4- (1467) nonenterotoxigenic E. coli (non-ETEC) strains, respectively. The pigs from the fourth group were inoculated with F4ac+ ETEC strain M1823 and the remaining 5 pigs that received broth containing 1.2% sodium bicarbonate were kept as noninoculated controls. The pigs were examined daily and the frequency and duration of their behavioral patterns, such as eating, drinking, lying, standing, urinating, defecating, rooting and playing were monitored for 300 h during a period of 10 days. In this model, three conditions were also observed in F4-susceptible pigs: (1) acute fatal diarrheal disease; (2) moderate diarrhea and weight loss and (3) no diarrhea and weight loss. The incidence (both frequency and duration) of defecating was significantly higher (P < 0.05) in pigs inoculated with F4ac+ ETEC strain M1823 as compared to that of noninoculated (control) pigs. Pigs inoculated with F4ac+ non-ETEC strain 1466 had a significantly lower frequency of eating (P < 0.05) and frequency/duration of drinking (P < 0.05) than did the controls. The 1466-inoculated pigs, had an increased diarrhea score, but frequency/duration of defecating was not significantly different. Pigs inoculated with F4ac+ non-ETEC strain 2407 spent more time in lying (P < 0.05) than did noninoculated pigs. Conversely, the pigs that received F4- non-ETEC strain 1467 laid shorter (P < 0.05) and ate/drank less frequently (P < 0.05) than the controls. It was concluded that the changed occurrence of defecating and eating in pigs that were inoculated with either F4ac+ ETEC (M1823) or non-ETEC (1466) strain. respectively, was consistent with the pending clinical disease, i.e. postweaning colibacillosis.

Preweaning losses of piglets on a state farm in Bosnia and Herzegovina

Abstract The objective of a 3 year pilot survey of preweaning mortality on a large swine farm in Bosnia and Herzegovina was to provide producers and/or veterinarians with information about causes of piglet losses, their occurrence and frequency at the herd (regional) level. This may also serve as a model for an assessment at the national level. The SNOVET system, a part of the National Animal Health Monitoring System (launched in the USA in 1985), was applied for the classification of causes of deaths among suckling piglets based on postmortem findings. To assess the incidences of causes of preweaning losses, 354094 piglets born in 34 648 litters were monitored daily from June 1985 to May 1988. Respective information from 20 682 (or 5.8%) stillborns and those piglets that died from birth to weaning (49 058 or 14.7%) was given. Among piglets born alive, overlaying was the most frequent cause of death (6%), followed by mortality due to gastrointestinal syndrome (3.9%), cachexia/inanitio neonatorum (2.2%), and losses of small or deformed piglets (1.6%). The incidence of pneumonia was very low (0.02%). A relatively high proportion of causes of mortality remained unknown (0.9%) partly owing to savaging or losing piglet corpses in the sewers. The use of recorded information on type, extent, and incidence of piglet mortality (gathered on the sample of appropriate size) on a long-term basis may help in the development of effective strategies to reduce/control losses until weaning.

Identification of infant and adult swine susceptible to enterotoxigenic Escherichia coli by detection of receptors for F4(K88)ac fimbriae in brush borders or feces

We attempted to determine F4(K88)-adhesive and non-adhesive phenotypes of infant (neonatal < 3 day old and weaned < 4 week old pigs) and adult (> 6 month old) swine by ELISA using immobilized F4(K88)ac fimbrial antigen or whole F4(K88) + E. coli cells (strains M1823 and 1476) and isolated small intestinal brush borders or easily-obtainable fecal samples from the same animals. Nineteen of 22 neonates (86%), 17 of 20 weaners (85%), and 26 of 39 adults (67%) were classified identically as F4(K88) receptor-positive or negative by the ELISA. The ELISA with feces from adult swine was found to be almost equally specific (87%) as that with feces from neonatal (90%) and weaned (91%) pigs. However, the sensitivity of the assay was low (38%), indicating that fecal samples from adults contained less receptor-material than necessary for comparable phenotyping. The receptor-positive brush borders from neonates and weaners reacted significantly better (P < 0.02, < 0.001 respectively) with purified F4(K88) antigen than did those from adults. There was good agreement between the average ELISA values for feces from infant and adult swine regardless the source of coating antigen applied. With this assay we can determine F4(K88) phenotypes of infant swine using easily-collected fecal samples rather than isolated brush borders. It was also concluded that tested feces is not an acceptable alternate source of the receptor-material to brush borders from F4(K88)-susceptible adult swine.