The porcine acute phase protein response to acute clinical and subclinical experimental infection with Streptococcus suis

The pig acute phase protein (APP) response to experimental Streptococcus suis (S. suis) infection was mapped by the measurement of the positive APPs C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp) and major acute phase protein (pig-MAP) and the negative APPs albumin and apolipoprotein (Apo) A-I. The aim was to elucidate the differences in the acute phase behaviour of the individual APPs during a typical bacterial septicaemic infection. Pigs were inoculated subcutaneously with live S. suis serotype 2 and blood was sampled before and on various days post inoculation (p.i.), until the pigs were killed and autopsied on day 14 p.i. Clinical signs (fever and lameness) were observed in four of the five inoculated pigs from day 2 p.i., and these pigs also had arthritic lesions at autopsy. CRP and SAA showed fast increases in serum concentrations, CRP being elevated from days 1 to 12 p.i. and peaking at 10 times the day 0-levels on day 1 p.i. SAA rose quickly to peak levels of 30-40 times the day 0-level on days 1-2 and returned to pre-inoculation level on day 5 p.i. Hp and pig-MAP showed slightly slower responses, both peaking around 5 days p.i. Hp was increased throughout the experiment with maximum levels around 10 times the day 0-levels, and pig-MAP was elevated on days 1-12 p.i. with peak levels of around seven times the day 0-levels. Apo A-I was decreased from days 1 to 8 and showed minimum levels of about 40% of day 0-levels around 1-2 days p.i. No clear pattern of changes in albumin levels could be identified. One pig, showing clinical signs on day 2 only, also showed an APP response, although of a relatively short duration, whereas three pigs presenting clinical signs for several days had a more protracted acute phase response. Remarkably, the one pig showing no clinical signs and no arthritic lesions showed an APP response comparable to that of the other, clinically affected pigs. Thus, both acute clinical and subclinical S. suis infection could be revealed by the measurement of one or more of the APPs CRP, SAA, Hp, pig-MAP and Apo A-I. The combined measurement of two or three APPs, including proteins with slow and fast kinetics, should be used to achieve the highest sensitivity for the detection of ongoing S. suis infection during a prolonged time period. A diagnostic tool based on such APP-measurements could considerably improve strategic control procedures for this important infection.     

Testing methods for PSE syndrome: Current research in DenmarkMéthodes de testage sur le syndrome PSE: Recherches en cours au DanemarkMethoden zur Feststellung des PSE-Syndroms: Aktuelle Forschung in Dänemark

The purpose of the paper is to describe research carried out in Denmark in areas associated with PSE.In the carcass, meat colour is used as an expression of meat quality. Meat quality deteriorated until 1972 but has improved substantially during the last 6–7 years.The incidence of halothane susceptibility in the Danish Landrace breed is low. Approximately 60% of the halothane-susceptible pigs had PSE carcasses compared to 22% for the non-susceptible pigs. However, pigs heterozygous at the Hal locus are intermediate in meat quality, and elimination of the gene for halothane susceptibility will lead to a substantial improvement in meat quality. A proportion of halothane-susceptible pigs as well as heterozygous carriers can be detected indirectly by using the H blood group system alone or in combination with the PHI system. This is due to linkage disequilibrium between the three systems within the Danish Landrace breed. Use of the H and PHI systems and the halothane test in combination with full sib information on KK index may increase the genetic gain by 5–30%. However, a greater extra gain is easily obtained by a slight increase in selection intensity based on the KK index alone. Thus, it does not seem profitable to use blood and enzyme types or halothane test as a routine in selection against PSE under Danish conditions. In contrast, these tests are useful within herds with a high frequency of PSE.     

FC-6 Four isoforms of exfoliative toxin produced by Staphylococcus hyicus abolished immunofluorescence for desmoglein 1 in pig skin

Western immunoblotting studies of canine sera using Malassezia pachydermatis extracts have shown that infected dogs commonly have antibodies that recognize multiple antigens. However, reported patterns of immunoreactivity vary between different laboratories. Since culture duration influences the antigenic composition of lipid-dependent Malassezia when probed with human sera, we investigated whether the in vitro growth phase of M. pachydermatis influences immunoreactivity to canine sera. Extracts of M. pachydermatis CBS1879 grown in Sabouraud's liquid medium at 37°C for 2, 4, 6, 8 and 10 days were prepared by mechanical disruption, centrifugation, dialysis and lyophilization. Yeast growth phase was assessed by sequential colony counts and optical density measurements. Patterns of IgG immunoreactivity in high ( n  = 3) and low ( n  = 3) titre sera were compared using extracts prepared at each time point by SDS-PAGE and western immunoblotting. Protein bands of 62 and 49 kDa were recognized by all sera, and five sera recognized 98 and 68 kDa bands. Proteins of 188, 66, 58, 57, 38, 28 and 17 kDa were only recognized by high titre sera. All high titre sera recognized more bands in exponential phase (day 2) extracts when compared with decline phase (days 8–10) extracts, and two of these sera showed most bands in stationary phase (days 4–6) extracts. Bands of 62 and 57 kDa were primarily detected in exponential and early stationary phase extracts. Antigenic variation in extracts of M. pachydermatis prepared during different growth phases might explain discrepancies between previous laboratory studies of immunity to this yeast.
Funding: Government of Malaysia.     

West Nile encephalitis.

WNV encephalitis in horses, previously reported in Africa, Asia, and Europe, occurred for the first time in the Western Hemisphere in 1999. The causative agent, WNV, is a flavivirus maintained in nature by a bird-mosquito cycle. The disease in horses is manifested primarily by ataxia of variable severity. Outbreaks of encephalitis may have a case fatality rate in excess of 40%, although this virus infection is inapparent in some horses. Early evidence indicates that WNV has overwintered in the northeastern United States and poses a threat for future disease occurrences in horses. No vaccine is available to protect against WNV infection in horses; disease control is predicated on mosquito abatement.     

Possibilities of contraception, artificial abortion and premature labor in cattle

Means of contraception and abortion in cattle are discussed. Estrog en injections (diethylstilbestrol or estradiol benzoate) may be given within a few days of conception, as may oxytocin and prostaglandins. Infusion of a sterile solution into the uterus is another means of inducing abortion. Intrarectal applications of estrogens can also be used to suppress the corpus luteum. Later in pregnancy, injury to the fetus or the membranes, or surgical removal of the fetus are possible. Estrogen or corticosteroid treatment may also be used to induce labor. Because the sperm must be immobilized before they reach the tubes, contraception is difficult to carry out in practice.