Anders Engvall

Campylobacter incidence on a chicken farm and the spread of Campylobacter during the slaughter process

To get a better understanding of the epidemiology of Campylobacter, a chicken farm was studied for 16 weeks with samplings in each flock weekly from input until the flock became colonized with Campylobacter or slaughtered. Samples were taken from fresh droppings and from drinkers during the rearing period, as well as from the environment in empty houses. The spread of Campylobacter during the slaughter process was also surveyed. No Campylobacter was found in samples from newly-hatched or one-week-old chickens or their drinkers. All flocks but one were colonized at two to five weeks of age. All Campylobacter isolates belonged to the same sero- and biotype; C. jejuni Penner 2. The spread of Campylobacter in the flock was rapid and usually all samples were positive once colonization had been proven. C. jejuni was isolated from flies in ante-rooms as well as from air in chicken units in houses with positive chicken flocks. Samples were taken at slaughter when some of the Campylobacter positive flocks from the farm were slaughtered. Campylobacter were isolated from all sampled equipment along the processing line, from the chicken transport crates to the chillers, as well as from the air.

A 1-year epidemiological study of campylobacters in 18 Swedish chicken farms

Broiler chickens are often intestinal carriers of Campylobacter. During processing, Campylobacter may be spread over the carcass. Thus, undercooked chicken meat, or other foods contaminated by raw ...

Distribution and numbers of Campylobacter in newly slaughtered broiler chickens and hens.

If Campylobacter is present in the intestinal tract, broiler carcasses become extensively contaminated during the slaughter process. To determine the distribution and numbers of Campylobacter jejuni/coli in newly slaughtered broiler chickens and hens, a total of 100 birds from six Campylobacter-positive flocks were sampled at three Swedish processing plants. Campylobacters were isolated in 89% of neck skins, 93% of peritoneal cavity swab samples and in 75% of subcutaneous samples. Muscle samples were only very sparsely contaminated. It is likely that the feather follicles are the orifices where C. jejuni/coli is introduced into the subcutis layer.

Control of Salmonella enteritidis in Sweden

The Swedish control of Salmonella, with special reference to Salmonella enteritidis, in poultry is described. The control is directed at all serotypes of Salmonella and imported grandparent chickens are controlled, which is considered to be the main reason why Sweden so far is not found to be involved in the worldwide spread of different phagetypes of S. enteritidis. However, this spread has initiated a more stringent control of Salmonella in layers as earlier existed in broilers. Since 1990, 90% of the layer flocks are voluntarily tested for Salmonella before slaughter by bacteriological examination of pooled faecal samples. If S. enteritidis is isolated the flock is destroyed. This test, and in addition two similar tests during the production are mandatory as of January 1st, 1994. The voluntary Salmonella control programme has also been extended to all of the layer parents and hatcheries since 1991. Only heat-treated feed is given to all layer chickens during the rearing period and its use is becoming gradually more common also during the production period. Since 1987, four layer flocks have been found to be infected by S. enteritidis phagetype 4 and one flock with phagetype 6. During 1970-1984, 90% of all flocks of broilers were voluntarily tested bacteriologically for Salmonella before slaughter, and since 1984 such a control is mandatory to all flocks. As a result of this and other controls, S. enteritidis has not been isolated from broilers since 1972. Based on a governmental regulation from 1961, introduced as a result of a large Salmonella epidemic in 1953, Sweden runs an active, official control of Salmonella (Wierup et al., 1992).(ABSTRACT TRUNCATED AT 250 WORDS)

Salmonella isolated from animals and feed production in Sweden between 1993 and 1997.

AbstractThis paper presents Salmonella data from animals, feedstuffs and feed mills in Sweden between 1993 and 1997. During that period, 555 isolates were recorded from animals, representing 87 serotypes. Of those, 30 serotypes were found in animals in Sweden for the first time. The majority of all isolates from animals were S. Typhimurium (n = 91), followed by S. Dublin (n = 82). There were 115 isolates from cattle, 21 from broilers, 56 from layers and 18 from swine. The majority of these isolates were from outbreaks, although some were isolated at the surveillance at slaughterhouses. The number of isolates from the feed industry was similar to that of the previous 5-year period. Most of those findings were from dust and scrapings from feed mills, in accordance with the HACCP programme in the feed control programme. It can be concluded that the occurrence of Salmonella in animals and in the feed production in Sweden remained favourable during 1993–97.SammanfattningSalmonella isolerad från djur och foder i Sverige under perioden 1993-1997. Denna studie ingår i en serie som presenterar Salmonella- isolat från djur och foder i Sverige, med början 1949. Under perioden 1993 till 1997 rapporterades 555 isolat från djur. Under perioden 1988-92 isolerades 598 isolat från djur. Jämförelser av resultat mellan de olika studierna måste göras med försiktighet eftersom provtagning och övervakning kan ha varierat mellan de olika studieperioderna. Antalet isolat från nötkreatur var 115, medan 21 var från slaktkycklingar, 56 från värphöns, och 18 från svin. För första gången härrörde majoriteten av isolat från annat djurslag (165 isolat från reptiler) än nötkreatur. Iden aktuella studien registrerades 87 olika Salmonella- serotyper, vilket är det största antalet som har rapporterats i serien. Trettio av dessa serotyper isolerades från djur i Sverige för första gången. Majoriteten av isolat visade sig tillhöra S. Typhimurium (n=91), följt av S. Dublin (n=82). Antalet isolat från foder (n=749) skilde sig inte väsentligt från den föregående rapporteringsperioden. Majoriteten av de positiva proverna härrörde från prover som insamlades enligt HACCP principer i kontrollprogrammet för foder. Det kan sammanfattas att Salmonella-situationen i Sverige var god under den aktuella studieperioden och tyder på att kontrollprogrammet fungerar tillfredsställande i strävan att hålla hela livsmedelskedjan från jord till bord fri från kontamination.

A Reed-Frost model of the spread of tuberculosis within seven Swedish extensive farmed fallow deer herds

The within-herd transmission of tuberculosis, after introduction of infection, was evaluated in seven Swedish herds of farmed fallow deer. The evaluation was based on a subset of data obtained from a previous epidemiological investigation, comprising 13 tuberculosis-infected deer herds, with the purpose of tracing the source of infection. A computer spreadsheet model based on the Reed-Frost method was developed to estimate the number of new infections. For each herd, a k-value (the number of effective contacts made by an individual during a time period) was estimated through fitting the model to the observed incidence in each herd. We concluded that, despite the relatively short observation periods and uncertain tuberculosis incidence estimates for the observed herds, the ks obtained could be used to quantify the estimated spread of tuberculosis in extensive deer herds in Sweden.

May Organically Farmed Animals Pose a Risk for Campylobacter Infections in Humans

Organic farming of meat producing poultry like broilers, means that the animals should be kept outdoors as much as possible. This pose a risk that they get infected with Campylobacter. At slaughter, carcasses may be contaminated with campylobacter. If cross contamination occurs in the kitchen or if the meat is undercooked people may ingest the bacteria and suffer from enteritis. It seems possible that close to 100 percent of organically farmed flocks may be infected with campylobacter while under Swedish conditions only 10 percent of conventionally reared flocks are infected.

Experimental colonization of mice with Campylobacter jejuni.

The ability of one human and two chicken strains of Campylobacter jejuni to colonise and survive in three different strains of laboratory mice (NMRI, CBA and C57-Black) was studied. Mice were inoculated orally with Campylobacter jejuni and faeces samples were cultured at regular intervals during the following months. The length of colonisation of mice differed between mouse strains but also between Campylobacter strains. The mouse strain C57-Black was not colonised with C. jejuni to the same degree as the other mouse strains. It is concluded that mice can become colonised for prolonged periods and that they may act as reservoirs of Campylobacter for other species.

Risk of introduction of BSE into Sweden by import of cattle from the United Kingdom

All cattle of United Kingdom origin imported to Sweden since 1980 were traced (n=94) and the probability that none of these imported cattle had clinical signs of bovine spongiform encephalopathy (BSE) at the year of slaughter (death) was calculated. If BSE had been introduced by live-animal imports, the consequences of such an event also was evaluated. The potential of the recently introduced surveillance system of high-risk cattle to detect such an event also was evaluated. We found that BSE most probably has not been introduced to Sweden by live-animal imports. We also found that, if this event had occurred and assuming a worst-case scenario that the animal was not prevented from being rendered, the rendering system (during certain periods) would not have prevented further spread of infection. Finally, we found that the BSE surveillance of high-risk cattle has not been in place long enough to verify that this event has not occurred (as of December 2001).