An Outbreak of Classical Swine Fever (CSF) in a Closed-Cycle Unit in Israel
In a closed pig holding facility containing 425 sows, located in northern Israel, a Classical Swine Fever (CSF) outbreak occurred, which caused the loss of 267 sows (62.8% of the farm sow population), 4 boars (out of 6), and 828 growing/fattening pigs (41.4% of the total on the farm), through direct mortality, partial culling, and an unknown number of abortions. The CSF outbreak started among the pregnant sows, with high fever, cyanosis, abortions, lameness, vomiting, and mortality (24.8% of sows and 33.3% boars). At necropsy, hemorrhages were found on the parietal pleura, diaphragm, epicardium and kidney; lymph nodes were congested and hemorrhagic; necrotic lesions were present on the mucosa of the small intestine. CSF was diagnosed at Kimron Veterinary Institute by reverse transcriptase polymerase chain reaction (RT-PCR) method and with ELISA-antibody test on serum and ELISA-antigen test on organ homogenates. The results were confirmed by the EU Reference Laboratory at Hanover, Germany with Real Time–PCR on blood and organs. Phylogenetic analysis showed that CSFV sequences of the Israeli virus isolates belonged to genotype 2.1. Molecular typing and comparison of amino acids with CSFV subgroup 2.1 isolates from Southeast Asia and from Europe revealed that the CSFV isolate responsible for the Israeli outbreak was genetically most similar to a Chinese CSFV isolate. Involvement of wild boars, which were in contact with sows was suspected. Samples from blood and organs taken from wild boars found in the vicinity of the farm were found positive for CSF. Following confirmation of CSF, elimination of clinically sick animals and vaccination of the remaining population in the holding and the surrounding area were implemented.
Factors associated with the introduction of classical swine fever virus into pig herds in the central area of the 1997/98 epidemic in the Netherlands
A matched case-control study of 135 infected and 99 uninfected pig herds from the central area of the 1997 to 1998 epidemic of classical swine fever (CSF) in The Netherlands was undertaken to identify factors associated with the introduction of the virus. The herds were matched on the basis of herd type and the shortest geographical distance between pairs of herds. Data on management, hygienic measures, experiences during the depopulation of an infected nearest neighbour, and the frequency of contact with professionals and other agencies were collected by means of a questionnaire taken by personal interview. There were no significant differences between the infected and uninfected herds in the median total number of contacts per year with professionals and other agencies either with or without contact with the pigs. On the basis of a multivariable analysis, five variables were found to be significantly associated with an increased risk of infection: (1) the presence of commercial poultry on the premises; (2) visitors entering the pig units without wearing an overcoat or overalls and boots supplied by the farm; (3) the driver of the lorry transporting pigs for the Pig Welfare Disposal Scheme (PWDS) using his own boots instead of boots supplied by the farm; (4) herds of moderate size (500 to 1000 animals) and very large herds (>7000 animals) were at greater risk than small herds (<500 animals); and (5) an aerosol, produced during high-pressure cleaning of the electrocution equipment used to kill the pigs on a neighbouring infected herd less than 250 m away was carried by the wind on to the premises. Two variables were significantly associated with a decreased risk of csFv-infection: (1) more than 30 years of experience in pig farming; and (2) additional cleaning of the lorries used to transport pigs for the PWDS before they were allowed on to the premises. In the opinion of the cooperating farmers, airborne transmission of the virus and its transmission during the depopulation of an infected neighbour were among the most important routes of infection.
Microbial flora of frozen tail meat from captive Nile crocodiles (Crocodylus niloticus).
Frozen tail meat samples from nine Nile crocodiles (Crocodylus niloticus) were evaluated for microbial numbers and types. Microbial analyses yielded a mean aerobic plate count (APC, 30 degrees C) of 4.86 log cfu/g, a mean coliform count (TC, 37 degrees C) of 3.77 log cfu/g and a mean faecal coliform count (FC, 44 degrees C) of 3.40 log cfu/g. Salmonella was isolated from three samples, and beta-haemolytic streptococci from two samples. Yersinia, Aeromonas, Staphylococcus aureus and Bacillus cereus were not isolated. Typical bacterial genera recovered included Flavobacterium, Pseudomonas, Acinetobacter, Enterobacter, Moraxella, Micrococcus, Staphylococcus and Streptococcus.