Wild animals living close to cattle and pig farms (four each) were examined for verocytotoxin-producing Escherichia coli (VTEC; also known as Shiga toxin-producing E. coli). The prevalence of VTEC among the 260 samples from wild animals was generally low. However, VTEC isolates from a starling (Sturnus vulgaris) and a Norway rat (Rattus norvegicus) were identical to cattle isolates from the corresponding farms with respect to serotype, virulence profile, and pulsed-field gel electrophoresis type. This study shows that wild birds and rodents may become infected from farm animals or vice versa, suggesting a possible role in VTEC transmission.

Aims:  To investigate the transmission of Salmonella spp. between production animals (pigs and cattle) and wildlife on production animal farms in Denmark. Methods and Results:  In the winter and summer of 2001 and 2002, 3622 samples were collected from Salmonella‐infected and noninfected herds of pigs and cattle and surrounding wildlife. Salmonella was detected in wildlife on farms carrying Salmonella‐positive production animals and only during the periods when Salmonella was detected in the production animals. The presence of Salmonella Typhimurium in wild birds significantly correlated to their migration pattern and food preference. Conclusions:  Salmonella was transmitted from infected herds of production animals (cattle and pigs) to wildlife that lived amongst or in close proximity to them. Significance and Impact of the Study:  Salmonella in animal food products is associated with the occurrence of Salmonella in primary animal production. Strategies to control the introduction and spread of infection should include wildlife management, as the nearby wildlife may act as reservoirs for Salmonella spp. and/or may be passive carriers of the bacteria.

The rat model of Pneumocystis carinii pneumonia is frequently used to study human P. carinii infection, but there are many differences between the rat and human infections. We studied naturally acquired P. carinii in wild rats to examine the relevance of the rat model for human infection. P. carinii DNA was detected in 47 of 51 wild rats and in 10 of 12 nonimmunosuppressed laboratory rats. Evidence for three novel formae speciales of rat-derived P. carinii was found, and these were provisionally named Pneumocystis carinii f. sp. rattus-secundi, Pneumocystis carinii f. sp. rattus-tertii, and Pneumocystis carinii f. sp. rattus-quarti. Our data suggest that low-level carriage of P. carinii in wild rats and nonimmunosuppressed laboratory rats is common and that wild rats are frequently coinfected with more than one forma specialis of P. carinii. We also examined the diversity in the internally transcribed spacer (ITS) regions of the nuclear rRNA operon of Pneumocystis carinii f. sp. carinii by using samples from wild rats and laboratory rats and spore trap samples. We report a lack of variation in the ITS1 and ITS2 regions that is consistent with an evolutionary bottleneck in the P. carinii f. sp. carinii population. This study shows that human-and rat-derived P. carinii organisms are very different, not only in genetic composition but also in population structure and natural history.Animal models have been widely used as a source of Pneumocystis carinii organisms and for studying many aspects of P. carinii infection. This is because sustained in vitro cultivation of P. carinii has not been possible (1, 38), although recently a new method has been reported which is now being evaluated in a number of centers (25). The rat model has been particularly useful in studies of epidemiology (11, 50), drug sensitivity (59), immunology (51), and the biology of the organism (42). Ratand human-derived P. carinii organisms, however, are known to differ significantly in many respects. Considerable divergence has been shown between the genes of rat-and humanderived P. carinii (36,43), as well as antigenic (9) and ultrastructural (5) differences.Two genetically divergent types of P. carinii organisms, known as Pneumocystis carinii f. sp. carinii and Pneumocystis carinii f. sp. ratti, have been found in rat lungs (34). These were originally identified by differences in electrophoretic karyotype (7) and subsequently by DNA sequence variation at a number of genes, including those for the nuclear 26S rRNA (21, 29), the mitochondrial large-subunit (mt LSU) rRNA (14), the mitochondrial small-subunit rRNA (12), the TATA binding factor (45), BiP chaperonin (40), thymidylate synthase (14), and ATPase (24), and the ␣ subunit of the G protein (39). The level of genetic divergence between these two types of ratderived P. carinii was sufficiently high for them to be classed as different formae speciales (34, 44). Although eight different electrophoretic karyotypes of P. carinii f. sp. carinii and two of P. carinii f. sp. ratti have been identifi...

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The correlation between farm characteristics and the occurrence and importance of rodent pests on outdoor pig farms in Denmark was explored in an extensive questionnaire survey, Mice occurred on most farms but were only rarely considered a problem, as opposed to rats, which were controlled on more than half of the farms, A series of trapping studies showed a high small-mammal diversity in and around the pigsties, The presence of rats was positively correlated with farm size, the presence of straw stacks near the pigsties and the use of automatic feeders, Rats were considered a problem more often when open drinking basins were used or when feed was stored near the pigsties, The environment of the farm did not play an important role except to some extent the proximity of hedges, Recommendations for preventative rodent management include avoiding conditions indicated previously, frequent mucking out and movement of huts, keeping feed in rodent-proof containers, avoid spillage of fodder, and general cleanliness, Direct control methods include application of rodenticides with proper consideration for the risk of unintended poisoning of production animals, the use of traps, keeping dogs or cats, and possibly shooting,

Vector control in plague-infested areas requires a simultaneous killing of rodents and their fleas. We investigated the efficacy of a combination of a systemic insecticide, fipronil, in a rodenticide bait formulation under laboratory conditions. Four different concentrations of fipronil (0.05%, 0.005%, 0.0005% with acetone as a solvent, and 0.05% with propylene glycol as a solvent) and two controls (solvents only) were combined with the rodenticide bait (crushed organically grown wheat with 0.005% bromadiolone). Each concentration was offered together with an untreated non-poisonous challenge bait to 10 singly caged Rattus rattus L., each with 100 rat fleas Xenopsylla cheopis Rothschild (Siphonaptera: Pulicidae) in the nest. Treated bait consumption was relatively low and an unsatisfactory rat mortality of around 50% only was obtained in all tests. The palatability of the bait, however, was not affected by the fipronil concentration. Even at the lowest fipronil concentration, average flea mortality was still above 95%, and doses of more than I mg fipronil per kg rat body weight gave a nearly complete kill of fleas. Fipronil can be highly effective as a systemic insecticide to for flea control, provided that a more attractive bait base for roof rats is used.

From 26 to 28 May 2004 an international seminar was held in Wageningen, the Netherlands, about current knowledge and advice on rodent management on organic pig and poultry farms in Western Europe. This paper summarizes the discussions. Rodent management is necessary to protect the food production chain from health hazards to livestock and humans. Some organic farmers prefer biological rodent control, but since rodents can also transmit diseases this bears certain risks for the production of healthy livestock and safe food. Effective rodent management requires a thorough understanding of the biology of the pest species concerned. These can be divided into two groups: field rodents, such as voles, and commensal rodents like house mice and rats. The objective of managing field rodents is to minimize livestock exposure to these vectors, and to regulate their populations in case their density is expect-195 NJAS 52-2, 2004 ed to grow dramatically. Infestation of livestock facilities with commensal rodents can be prevented, but once they are present, their eradication must be aimed for. General elements of rodent management are (1) the prevention of rodent infestations through strategic actions such as modifying the habitat or rodent proofing of the buildings, (2) monitoring their appearance and population density, and (3) rodent control measures. A number of possible management actions is described to provide a basis for examining the measures' social acceptability, their economic and environmental impacts, and their efficacy.

Little is known about the risk of Salmonella infection in outdoor pig production, but seroprevalence data have indicated a higher incidence of Salmonella in outdoor than in conventional indoor production systems. This higher incidence may be due to an increased exposure of the animals to the surrounding environment, including contact with wildlife. In a study on the transmission of Salmonella to outdoor pigs an unexpected high diversity of Salmonella serotypes that are not normally isolated from pigs, like for instance S. Uganda and S. Goldcoast, was detected in faecal and in soil and water samples. However, in a small-scale wildlife survey to elucidate the potential source of the different Salmonella serotypes, the bacterium was not detected in any of a total of 22 rats, mice and shrews nor in 22 birds (mainly crow-birds; Corvidae). The unidentified source of the Salmonella serotypes isolated implies inadequate control possibilities and may therefore pose a problem to outdoor pig production in terms of food safety.