Procedures for preventing the transmission of foot-and-mouth disease virus to pigs and sheep by personnel in contact with infected pigs.

The most effective method of containing an outbreak of foot-and-mouth disease (FMD) is by the culling of livestock. However, qualified people must diagnose the disease before the culling can begin, and they must avoid susceptible animals after having been in contact with infected premises, to prevent them from transmitting the virus. To test the effectiveness of biosecurity procedures in preventing the transmission of FMD virus (O/UK/35/2001) investigators contacted and sampled pigs inoculated with FMD virus for approximately 45 minutes and then contacted and sampled sentinel pigs and sheep after either using no biosecurity procedures, or washing their hands and donning clean outerwear, or showering and donning clean outerwear. The virus was detected in the nasal secretions of one investigator immediately after the postmortem investigation of the inoculated pigs but was not detected in samples collected between approximately 12 and 84 hours later. After the contaminated personnel had showered and changed into clean outerwear they did not transmit the strain of FMD virus to susceptible pigs and sheep.

Acute nonfatal erysipelas in sows in a commercial farrow-to-finish operation.

Acute nonfatal erysipelas was diagnosed in 4 sows in a 1,000-sow commercial farrow-to-finish operation in Indiana. Sows were pyrexic, lethargic, lame, and had multiple, 1.3- to 7.6-cm, erythematous rhomboid skin lesions. Outbreak was attributed to failure to properly vaccinate pigs. Further morbidity and mortality were prevented by treatment of clinically affected sows and all pigs in close proximity with procaine penicillin G daily for 3 consecutive days and vaccination of all pigs with questionable vaccination status, using bacterin of killed Erysipelothrix rhusiopathiae. Periodic review of herd management protocols is important to ensure that recommended vaccination schedules are being followed and animals are receiving quality vaccinations. Human error can contribute to many production problems and should be included on the differential diagnoses list.

Demonstration of vertical transmission of Streptococcus suis in swine by genomic fingerprinting.

Isolates of Streptococcus suis serotype 5 collected from three sows and nine of their pigs at birth were analyzed by genomic DNA fingerprinting. The cleavage patterns of DNA from S. suis isolated from the sows matched the cleavage patterns of DNA from S. suis isolated from their respective pigs.

Evaluation of antibiotics for the elimination of the tonsillar carrier state of Streptococcus suis in pigs.

Seventy clinically normal 13-day-old crossbred pigs from 10 litters from a Streptococcus suis-infected herd were randomly assigned by litter and weight to 7 groups of 10 pigs each to determine whether different antibiotic regimens would eliminate the tonsillar carrier state of S. suis. Six antimicrobial regimens were tested: penicillin intramuscularly (IM) once daily (s.i.d.) for 3 consecutive days; penicillin IM s.i.d. for 5 consecutive days; ampicillin IM s.i.d. for 5 consecutive days; ampicillin per os s.i.d. for 5 consecutive days; ampicillin intranasally s.i.d. for 5 consecutive days; and ceftiofur sodium IM s.i.d. for 5 consecutive days. The seventh group consisted of untreated control pigs. Tonsillar swab samples were collected before treatment, and tonsillar tissue samples were collected after treatment for cultural examination for S. suis. Streptococcus suis was identified in pigs from all groups prior to treatment and after treatment. Pigs did not have clinical signs of disease during the study. All antimicrobial treatments tested in this study failed to eliminate the tonsillar carrier state of S. suis. Early weaning and medication used in this study were not effective for the elimination of the tonsillar carrier state of S. suis in pigs. Optimization of management and environment of pigs coupled with strategic medication of clinically ill animals should be used for control and prevention of mortality caused by streptococcosis.

Interaction of Mycoplasma hyopneumoniae and Pasteurella multocida infections in swine.

To investigate the interaction between Mycoplasma hyopneumoniae and Pasteurella multocida infection, 32 pigs were randomly assigned by litter, sex, and weight to 4 treatment groups. Group-1 pigs were inoculated with M hyopneumoniae and allowed to recover from M hyopneumoniae infection. Group-2 pigs were vaccinated against M hyopneumoniae and then inoculated with M hyopneumoniae. Group-3 pigs were inoculated with M hyopneumoniae and developed clinical signs of mycoplasmosis. Group-4 pigs had never been exposed to M hyopneumoniae. All pigs were initially seronegative for M hyopneumoniae. All pigs were subsequently inoculated with P multocida and euthanatized 2 weeks later. Pasteurella multocida was isolated only from the lungs of group-3 pigs, and these pigs had a significantly higher median percentage of lung surface area affected by pneumonia than did pigs in the other groups. For group-3 pigs, percentage of lung surface area affected by pneumonia was positively correlated with the number of P multocida colonies isolated. We concluded that P multocida is not a primary respiratory pathogen in pigs, but that M hyopneumoniae infection can render the lungs susceptible to P multocida colonization and infection. Pigs recovered from or vaccinated against infection with M hyopneumoniae were resistant to P multocida infection.