Increase in interleukin-6 following arterial injury is related to insulin resistance, the -174G-->C polymorphism and complex plaque morphology.

Interleukin-6 (IL-6) is associated with many disease states in humans. We prospectively sought to determine whether IL-6 levels increased following percutaneous coronary intervention (PCI) in the absence of myonecrosis. Additionally, we systematically assessed other clinical and anatomic factors associated with IL-6 levels in a population of patients with coronary atherosclerosis undergoing PCI. Blood samples were collected from 117 patients at baseline, 8 and 16 h following PCI. Samples were assayed for IL-6, creatine kinase-myocardial band (CK-MB), troponin-I (Tn-I), high sensitivity C-reactive protein, glucose, haemoglobin A1c, and a lipid profile. Genotyping of the -174G-->C polymorphism of the IL-6 gene was performed. IL-6 levels increased following PCI among the study group (slope = 0.4 pg/mL/h, P = 0.001). IL-6 levels increased to a similar degree in the absence of myonecrosis. Patients with the XC genotype (either having the GC or the CC allele) had higher IL-6-values at baseline compared to GG genotype patients (4.9 +/- 6.4 vs. 2.6 +/- 1.8 pg/mL, P = 0.02). Multivariable predictors of detectable baseline IL-6 levels included XC genotype (odds ratio [OR]: 4.14, 95% CI 1.58-10.82, P = 0.004), ACC/AHA type C lesion classification (OR: 4.08, 95% CI 1.54-10.84, P = 0.005), elevated baseline Tn-I (OR: 3.31, 95% CI 1.16-9.43, P = 0.025), diabetes (OR: 3.00, 95% CI 1.11-8.09, P = 0.030), and waist circumference (OR: 1.49, 95% CI 1.08-2.06, P = 0.015). Predictors of peak IL-6 following PCI included the XC genotype (estimate 1.4, 95% CI 1.06-1.87, P = 0.019), homeostasis model assessment (estimate 0.99, 95% 0.982-0.999, P = 0.042) and baseline Tn-I > upper limit of normal (estimate 0.7, 95% CI 0.50-0.96, P = 0.039). Lastly, IL-6 increased following PCI even in the absence of myonecrosis as measured by Tn-I elevation. IL-6 levels are also related to the -174G-->C polymorphism, arterial injury, lesion complexity, and insulin resistance.

Epizootic vesicular disease in captive California sea lions.

An epizootic of vesicular disease occurred in a group of semi-domesticated California sea lions (Zalophus californianus) during the months of April and May 1997. Ten castrated mature male sea lions, ages 12 to 19 yr, were housed in three adjacent open-ocean net enclosures in San Diego Bay (California, USA). Four animals (40%) developed oral and extremity vesicles, anorexia, and were reluctant to perform learned behaviors. One animal developed vesicles but maintained a normal appetite and behavior. The remaining animals showed no clinical signs of infection. Virus (designated FADDL 7005) was isolated from four of the five animals that developed vesicles. Serum antibody titers to FADDL 7005, a previously untyped calicivirus, were demonstrated in animals that showed any combination of clinical signs and in two animals that did not show any clinical signs. No virus was isolated from five fecal samples collected from four of the group animals. Clinical signs lasted 4 to 20 days in affected animals. All affected animals recovered from infection. An experimental swine was inoculated with FADDL 7005 and developed vesicular disease, which was transmitted to another experimental swine upon contact. It is proposed that FADDL 7005 is a new San Miguel sea lion virus.

Future international management of African horse sickness vaccines.

Three types of African horse sickness (AHS) vaccine, namely adult mouse brain, modified live vaccine and inactivated viral vaccine (IVV) are reviewed. The results of efficacy trials carried out with each vaccine type highlight the advantages of the IVV. Vaccination with African horse sickness virus serotype 4 IVV, given as 2 separate doses, provided full protection against subsequent, homologous challenge. The absence of any detectable viraemia after challenge would also prevent infection of insect vectors. The advantages of establishing international vaccine banks for AHS are discussed.

Viral serologic survey of bowhead whales in Alaska.

Serum samples from 21 of 36 Eskimo harvested bowhead whales (Balaena mysticetus) were positive by virus neutralization (50% endpoint titer > or = 1:28 and/or 100% endpoint titer > or = 1:20) for antibodies to at least one virus serotype from the calicivirus family, vesicular exanthema of swine virus (VESV) and San Miguel sea lion virus (SMSV). Many animals were positive to more than one serotype when using the Spearman-Karber (S-K) method for calculating antibody titers. The most common serotype detected was VESV F55 with 6 of 36 (17%) by the Monto and Bryan (MB) titer calculation method, and 17 of 36 (47%) by the S-K titer calculation method. Vesicular exanthema of swine virus 1934B antibody was detected in 3 of 36 (8%) and 5 of 36 (14%) whales using the MB and S-K methods, respectively. Vesicular exanthema of swine virus J56 antibody was detected in 3 of 36 (8%) by the S-K method only. All whales < 8.5 m (estimated yearlings, n = 6) were seronegative for VESV J56 and 1934B while 10% and 17% of the whales > 8.5 m were positive, respectively. Whales assumed to be sexually mature (> 13 m) had a higher prevalence of antibody to VESV 1934B and SMSV 8 than those < 13 m. Gender had an effect on seroprevalence of antibody to VESV 1934B as titers > or = 1:28 (S-K method) occurred in 18% of the females and 7% of the males. Antibody to other serotypes (SMSV 8 and 12) occurred less frequently (< 6%) at an antibody titer > or = 1:28 by the S-K method. All 36 whale sera were negative for antibody to VESV-A48, B51, C52, D53, E54, G55, H54, I55, and K54; Tillamook calicivirus, and dolphin morbillivirus; and SMSV-1, 2, 4, 5, 6, 7, 9, 10, 11, and 13 by the S-K method.

A blocking ELISA for detection of antibody to a subgroup-reactive epitope of African horsesickness viral protein 7 (VP7) using a novel gamma-irradiated antigen.

A novel gamma irradiated inactivated cell culture derived African horsesickness viral (AHSV) antigen was used in a blocking ELISA (B-ELISA) for detecting antibody to a subgroup-reactive epitope of AHSV. A monoclonal antibody (MAB), class IgM, against an epitope on African horsesickness (AHS) viral protein 7 (VP7) was developed in BALBc mice and used in the B-ELISA. The MAB, designated F9H, was blocked by 69 serums from equidae with antibody to AHS, but its binding activity was not appreciably affected by 301 serums that did not contain antibodies to AHS virus. An ELISA protocol using a blocking format is described.

Stabilization of rinderpest vaccine by modification of the lyophilization process.

Rinderpest (RP), a lethal disease of cattle, was almost eradicated from the African continent under Joint Project 15 (JP15), using an excellent modified live virus vaccine. Due to marked instability of the vaccine, a cold chain was required to ensure that the vaccine was potent at the time of application. Rinderpest re-emerged in the early 1980s. The Pan African Rinderpest Campaign (PARC) was developed to combat the new epidemic. For PARC to be efficacious and affordable, there was a clear need to have a vaccine that was thermostable. The need for a stable vaccine was underscored in politically unstable areas such as the Sudan, where the veterinary infrastructure has diminished and vaccination has been left in the hands of personnel who must act expeditiously. This paper reviews studies on various stabilizers and a modified lyophilization cycle that resulted in a highly thermostable RP vaccine. The useful shelf life of the vaccine, under African field conditions, was increased from less than one week to at least 100 days. For practical reasons, PARC recommends that the vaccine be used within 30 days of leaving refrigeration (the cold chain).

Epizootiology of morbillivirus infection in North American harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus).

A longitudinal study of morbillivirus infection among harbor (Phoca vitulina) and gray (Halichoerus grypus) seals on the Atlantic coast of North America was carried out between 1980 and 1994. Serology also was carried out on harbor seals from the Pacific northwest coast collected in 1992 and 1993. The prevalence of morbillivirus neutralizing antibodies was significantly (P < 0.0001) higher in gray (73%, n = 296) than in harbor seals (37%, n = 387) from the Atlantic. Titers were significantly (P < 0.0001) higher against phocine distemper (PDV) compared to any other morbillivirus. Antibodies were not detected in serum from Pacific harbor seals. During the winter of 1991 to 1992 an epizootic occurred among harbor seals on the northeast coast of the United States. The event was characterized by an increase in strandings and by a significant (P = 0.001) increase in PDV antibody prevalence to 83% (n = 36) in seals stranded that winter. Morbillivirus lesions and antigen were observed in six animals found stranded from southern Maine to Long Island, New York (USA), between November 1991 and April 1992. In addition, morbillivirus encephalitis was detected in tissues from a harbor seal that stranded in 1988. Enzootic infection appeared to be present in both seal species, although with a different prevalence of disease. We propose that enzootic infection among gray seals is facilitated by population size, high annual recruitment and innate resistance to clinical disease. Infection may be maintained in the smaller harbor seal population through casual contact with gray seals.

Analysis of the serologic relationship among San Miguel sea lion virus and vesicular exanthema of swine virus isolates. Application of the western blot assay for detection of antibodies in swine sera to these virus types.

Caliciviruses are positive-sense single-stranded RNA viruses with a single capsid protein. The serotypes of the marine mammal calicivirus, San Miguel sea lion virus (SMSV), are antigenically related to vesicular exanthema of swine virus (VESV) and are potentially hazardous to swine. Western blot assays using purified SMSV serotypes 1 and 4 were used to further examine the serologic relationship among SMSV and VESV isolates. With the exception of SMSV 8 and SMSV 12, rabbit polyclonal antisera generated against all the available SMSV and VESV isolates reacted positively, as assessed by western blot, with purified capsid protein from SMSV 1 and SMSV 4. Consequently, the SMSV 8 and SMSV 12 virus isolates may not be members of the SMSV/VESV calicivirus group. Using antisera from pigs experimentally inoculated with SMSV and VESV as positive controls, a western blot assay for these virus types was utilized to check for the presence of antibodies to calciviruses in swine sera. Sera from colostrum-deprived gnotobiotic pigs were used as a negative control in all experiments. Examination of sera from domestic and feral swine collected in Iowa, California, and Florida was completed using this technique. The presence of antibodies to these virus types was not detected in any of the porcine sera tested.

Comparison of monoclonal antibody-based sandwich enzyme-linked immunosorbent assay and virus isolation for detection of peste des petits ruminants virus in goat tissues and secretions.

A monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (S-ELISA) was developed for specific detection of peste des petits ruminants virus. Compared with virus isolation in Vero cell cultures using 89 paired tissue and secretion samples from six experimentally infected goats, S-ELISA was significantly more sensitive (71.9% versus 65.2%; P < 0.05). The S-ELISA is a suitable alternative to virus isolation.

Further studies on the efficacy of an inactivated African horse sickness serotype 4 vaccine.

The immunity induced by two inoculations of a commercial inactivated African horse sickness (AHS) serotype 4 (AHSV-4) vaccine was studied. No adverse reaction was observed in five horses following vaccination. Following challenge-inoculation, no clinical signs attributable to AHS, no viraemia indicating infection, and no anamnestic response was observed in the vaccinated ponies. Two control ponies developed clinical signs typical of AHS, high levels of viraemia, and died 7 and 8 days postchallenge-inoculation. The quality of immunity induced by the two-dose regimen was compared with a one-dose regimen from a previous study; in the one-dose study following challenge-inoculation, six of nine ponies were protected from clinical signs of AHS, seven of the nine vaccinated ponies developed an anamnestic response, and one pony had a viraemia about 10(3) 50% mouse lethal dose of AHSV-4 per ml of blood for 3 days following challenge-inoculation. The utility of an efficacious inactivated AHS vaccine in the control and eradication of AHS from a non-endemic area is discussed. The lack of viraemia following vaccination with an inactivated vaccine and the prevention of vector infection by animals exposed to field virus are important in the eradication of AHS.

Neutralizing antibodies to phocine distemper virus in Atlantic walruses (Odobenus rosmarus rosmarus) from Arctic Canada.

The first evidence of phocine distemper virus (PDV) infection in Atlantic walruses (Odobenus rosmarus rosmarus) from Nottingham Island, Northwest Territories, Canada, is reported. Blood samples were collected from three male walruses killed by Inuit hunters in the fall of 1990. Differential virus neutralization test for each animal yielded higher titers against PDV than against other members of the Morbillivirus genus including canine distemper, peste des petits ruminants, rinderpest and measles viruses. Thus, PDV infection may be enzootic in walruses of the eastern Canadian Arctic.

African horse sickness.

AHS is a noncontagious vector-borne disease of Equidae caused by Orbiviruses. Species susceptibility in decreasing order is horses, mules, donkeys, and zebras. The main vectors of AHS are culicoides. The disease is endemic in sub-Saharan Africa, but epizootics have occurred outside of this area on several occasions. The most recent outbreaks outside of the endemic area were in Spain, Morocco, and Portugal between 1987 and 1990. AHS causes mortality up to 95% and is classically divided into four clinical forms: the pulmonary, cardiac, mixed, and horse fever forms. Pathologic changes are subcutaneous and intermuscular edema and lung edema. The most consistent clinical signs include fever, nonpurulent conjunctivitis, and increased respiratory rate. Prevention and control measures include quarantines, control of insects, and vaccination. There is no treatment for AHS. Neurotropic strains of AHSV may cause retinitis and encephalitis in humans.

Monoclonal antibody-based blocking enzyme-linked immunosorbent assay for specific detection and titration of peste-des-petits-ruminants virus antibody in caprine and ovine sera.

A blocking enzyme-linked immunosorbent assay (B-ELISA), using two neutralizing monoclonal antibodies (MAbs), was established and compared with the virus neutralization test (VNT) for detecting specific peste-des-petits-ruminants virus (PPRV) antibody in caprine and ovine sera. This technique was developed because VNT, the only available specific serological test for PPRV and the cross-reactive rinderpest virus (RPV), is time-consuming and unaffordable for most laboratories in regions where both peste des petits ruminants and rinderpest occur. The test depends on the blocking of the binding of the MAb to a specific epitope in the presence of positive serum. Test conditions were optimized by using peste-des-petits-ruminants and rinderpest sera that were known to be VNT positive and negative. A blocking format, in which serum is preincubated with a solid-phase PPRV antigen and then incubated with the MAb, yielded levels of sensitivity and specificity superior to those of a competitive format, in which the two reagents are added simultaneously. A threshold value of 45% inhibition, representing the mean for a negative population (n = 277) plus 2.7 standard deviations, was adopted for routine screening. A total of 605 serum samples were screened by B-ELISA and the VNT. The sensitivity and specificity of B-ELISA relative to the VNT were 90.4 and 98.9%, respectively. Of 264 field serum samples tested, 11 (4.2%) could not be assayed by the VNT because of contamination or cytotoxicity; the overall agreement quotient between results of the two tests (n = 253) was 0.91. A high correlation (r>/=0.98) was observed between B-ELISA and the VNT for endpoint titration of sera (n=57). Because B-ELISA proved to be nearlyas sensitive and specific as the VNT while being simpler and more rapid, it would be an adequate substitute for the VNT for assessing herd immune status and for epidemiologic surveillance.

The use of thermostable Vero cell-adapted rinderpest vaccine as a heterologous vaccine against peste des petits ruminants.

The thermostable Vero cell-adapted rinderpest vaccine was evaluated in terms of immunogenicity as a heterologous vaccine against peste des petits ruminants. A titration to establish the minimum immunising dose was performed in American mixed breed goats by vaccinating test subjects with dilutions of Vero cell-adapted rinderpest vaccine and then challenging 26 days later with virulent peste des petits ruminants virus. All animals were followed for virus neutralising antibodies against both rinderpest and peste des petits ruminants virus after vaccination and challenge. The antibody response to vaccination was primarily against rinderpest virus with very low levels of cross-reactivity to peste des petits ruminants virus. Following challenge, animals which possessed anti-rinderpest neutralising antibodies remained clinically normal but mounted strong anti-peste des petits ruminants virus neutralising antibody responses indicating that replication of challenge virus took place without the induction of illness. The 50 per cent minimum goat immunising dose was 3 tissue culture infectious doses 50 per cent (TCID50) as established by serological response and protection against challenge. The thermostable Vero cell-adapted rinderpest vaccine is a suitable immunogen for the protection of goats against peste des petits ruminants.

Effect of gamma irradiation on reactivity of rinderpest virus antigen with bovine immune serum in enzyme-linked immunosorbent assays and virus neutralization and indirect fluorescent-antibody tests.

Gamma irradiation effectively inactivated gradient-purified rinderpest virus. Irradiated antigen and sera remained functional in enzyme-linked immunosorbent assays, virus neutralization tests, and indirect fluorescent-antibody tests. Irradiation, however, led to a dose-dependent decrease in reactivity, particularly significant (P < 0.05) when both reagents were irradiated. To avoid false-positive reactions, only one reagent (serum or antigen) may be irradiated.

Isolation of a virus with rhabdovirus morphology from a white-beaked dolphin (Lagenorhynchus albirostris).

A virus with rhabdovirus morphology which proved to be antigenically distinct from rabies virus and vesicular stomatitis virus was isolated from a dolphin that had beached on the Dutch coast. Neutralizing antibodies to this virus were found in several European marine mammal species.

Recommendations for African horse sickness vaccines for use in nonendemic areas.

African horse sickness (AHS), which causes mortality up to 95%, is caused by orbiviruses and is transmitted by Culicoides. The goal of a control and eradication program for AHS is to prevent the spread of the virus via the biological vector. Control measures include slaughter of infected animals, housing of suspected infected animals in insect-proof stalls, and vaccination. Vaccination has played a key role in eradication when AHS occurred outside of Africa. Both modified live vaccines (MLV) and inactivated vaccines have been used to control AHS. An acceptable vaccine should be: safe, efficacious, and available. The vaccine should not cause disease or viremia, and the vaccine virus should not revert to a virulent virus upon backpassage in susceptible Equidae. The vaccine should protect against death and clinical signs and, most importantly, should prevent viremia in vaccinated Equidae following exposure to virulent AHS virus. The challenge inoculation system for assessing immunity to AHS is discussed. The vaccine should be readily available, implying that it is either in routine production in facilities that meet internationally accepted guidelines for biological production facilities or in a vaccine bank. Banking of cryopreserved stocks of MLV or concentrates of inactivated vaccines is a means of having AHS vaccine available for future epizootics. A recently developed diagnostic test to differentiate vaccinated from naturally infected animals provides regulatory officials with useful information for the control of AHS.