Diagnosis of eastern equine encephalomyelitis virus infection in horses by immunoglobulin M and G capture enzyme-linked immunosorbent assay.

Immunoglobulin M (IgM) and G (IgG) capture enzyme-linked immunosorbent assays (ELISAs) were used as possible adjuncts to hemagglutination inhibition (HI) and virus neutralization (VN) tests to differentiate between reaction to recent exposure to eastern equine encephalomyelitis (EEE) virus and those due to prior vaccination. Serum samples were evaluated by the IgM-capture ELISA, and the results were compared with those of HI and VN tests. Of 381 serum samples, 51% (195 samples) were positive by HI test (> or = 1:40) and 54% (205 samples) were positive by VN test (> or = 1:10), but only 35% (132 samples) were positive by IgM-capture ELISA (> or = 1:100). With only a few exceptions, the sera with IgG ELISA titers had a VN titer of > or = 1:100. When EEE virus isolation and serology were compared, the EEE cases were divided into three categories: 1) peracute cases--the serum was negative for EEE IgM and IgG by the ELISA, negative for VN antibody, but HI antibody positive; 2) acute cases--IgM and HI antibody positive but negative for IgG and VN antibody; and 3) transitional cases--positive for IgM and IgG antibodies, HI titers of 1:40-1:160, and VN titers of > or = 1:100. IgM antibodies of EEE virus were monospecific and did not cross-react with western or Venezuelan equine encephalomyelitis viral antigens by the ELISA.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenic studies and antigenic and sequence comparisons of A/equine/Alaska/1/91 (H3N8) influenza virus.

An influenza virus, A/equine/Alaska/1/91 (H3N8), was isolated from horses from Alaska with an acute respiratory infection. Pathogenic and serologic studies revealed that this virus is similar to previously isolated equine H3N8 influenza viruses. Antigenic analyses utilizing hemagglutination inhibition and neuraminidase inhibition assays indicated an antigenic drift from the prototype equine H3N8 influenza virus, A/equine/Miami/1/63. Partial sequence analysis of the A/equine/Alaska influenza virus indicated that each of 8 gene sequences are of equine origin.

Fluorescent antibody technique to detect Cowdria ruminantium in in vitro-cultured macrophages and buffy coats from cattle, sheep, and goats.

Fluorescent antibody tests, Giemsa stain, and electron microscopy were used to detect colonies of Cowdria ruminantium in in vitro-cultured macrophages and buffy coats from heartwater-infected cattle, sheep, and goats. Antibodies were obtained from C ruminantium-infected cattle, sheep, and goats treated with a small dose of oxytetracycline HCl. Cowdria ruminantium elementary bodies were small-coccus forms (0.14 micron) and large-coccus forms (0.22 micron to 0.6 micron). The size of inclusion bodies varied from 1.5 micron to 2 micron. Inclusion bodies and elementary bodies were observed in the cytoplasm of macrophages and neutrophils.

Observation on the morphology of contagious equine metritis bacterial colonies isolated from infected pony mares.

In uterine or cervical specimens obtained from pony mares infected with streptomycin-resistant contagious equine metritis bacteria, several colonies of the bacteria which differed in morphologic characteristics were recognized during their primary isolation on Eugon chocolate agar and tryptose chocolate agar plates. The differences were usually not observed until plates were incubated 10 to 15 days. On Eugon chocolate agar plates, smooth colony, sandy colony with rings, and colony with blebs were recognized. On tryptose chocolate agar plates, only a round smooth convex colony was observed. By scanning electron microscopy, colonies consisted of coccal, coccobacillary, and bacillary forms. Only one type of colony was isolated from any mare.

Characterization of an isolate of mycoplasma WVU 907 which possesses common antigens to Mycoplasma gallisepticum.

Antigenic characteristics of an isolate of mycoplasma WVU 907 were compared with Mycoplasma gallisepticum (MG) and Mycoplasma synoviae. Mycoplasma WVU 907 and MG share common agglutinating and precipitin antigens. Although hemagglutinin is an integral part of WVU 907, hemagglutinating-inhibited antibody was not detected in sera of chickens inoculated with WVU 907. The clinical symptoms observed in chickens inoculated with WVU 907 were mild. Viral infections of chickens helped spread WVU 907 to contact controls. WVU 907 was more resistant to tylosin than MG was.

Contagious equine metritis: antibody response of experimentally infected pony mares.

Intrauterine inoculation of pony mares with the bacterium that is the causative agent of contagious equine metritis (CEM) resulted in clinical disease. A humoral immune response could be detected by agglutination and complement fixation (CF), and in some cases precipitating antibody was found by immunodiffusion tests. Agglutinating antibody was the most reliable serological indicator of overt infection and was detected in 8 ot 28 mares after initial intrauterine inoculation of 3-4 x 10(5) bacteria. Seventy percent of mares given a second inoculation and all mares given a third inoculation of 3-4 x 10(5) bacteria produced detectable agglutinating antibody. Only two of five mares given the third inoculation developed detectable complement-fixing antibody. Only one mare showed evidence of reinfection after a second or third intrauterine inoculation. All of the mares given a single intrauterine inoculum of greater than or equal to 8 x 10(8) bacteria produced agglutinating antibody 10 to 30 days postinoculation (DPI) and 86% gave a positive CF test 10 to 20 DPI. Only mares with an agglutination titer of 320 or more produced precipitating antibody. Sera were considered positive in agglutination tests if they were reactive at a dilution of greater than 4 and positive in CF tests if they were reactive at a dilution of 4 or greater.

Contagious equine metritis: effect of vaccination on control of the disease.

Pony mares were vaccinated with killed contagious equine metritis (CEM) bacteria by IV, subcutaneous, and intrauterine (IU) routes (or a combination of these routes). The serum agglutinating antibody titer varied from 1:64 to 1:1,024 after vaccination. In pony mares challenge exposed with 96-hour-old culture of CEM bacteria given by IU route, there were clinical signs of CEM, but these signs were less severe in vaccinated mares than in nonvaccinated mares. The bacterium was isolated for the exudate and from uterine samples collected from the mares after challenge exposure. A low titer of IU antibodies to CEM bacteria in infected mares was observed with agglutination tests (plate, tube, and antiglobulin), and enzyme-linked immunosorbent assay. However, a high antibody titer was obtained when passive hemagglutination test was used.

Contagious equine metritis: isolation and characterization of the etiologic agent.

Uterine, cervical, and clitoral specimens on swabs from pony mares infected with contagious equine equine metritis (CEM) bacteria were streaked on agar plates. Colonies of CEM bacteria were observed under CO2 incubation in 2 days on Eugon chocolate agar and Eugon blood agar plates. The diameter of the colonies varied from 0.2 mm to 1 mm in 2 days which increased to 0.3 mm to 2.0 mm on day 4. The colonies on Eugon chocolate agar plates on days 2 to 4 were shiny, brown, round, and convex, and easily glided when pushed with a loop. The diameter of the colonies on chocolate and blood agar plates made from tryptose blood agar base (TrCA or TrBA) was 0.2 to 0.3 mm on day 4. Due to their small size on TrCA or TrBA, colonies of CEM bacteria were easily recognized from large numbers of contaminants. The organism required hemin for its growth. It gelled in water, caused delayed hemolysis of blood agar plates, and was extremely susceptible to acid in the pH range to 3 to 4.5. A difference in growth of CEM bacterium was observed on primary isolation media obtained from two different commerical sources.

Contagious equine metritis: effect of intrauterine inoculation of contagious equine metritis agent in pony mares.

Actively growing culture of contagious equine metritis (CEM) bacteria or infective exudate (or both) were inoculated intrauterine in pony mares. A direct relationship was observed between (i) appearance and duration of cervicitis and vaginitis and (ii) vaginal exudate. Clinical signs appeared 1 to 3 days after mares were inoculated and lasted 7 to 23 days. In the acute phase of infection, all uterine and cervical samples yielded CEM bacteria. In the asymptomatic stage of infection, CEM bacteria were not isolated from uterine and cervical samples; however, in 33%, 28%, and 20% of the pony mares, CEM bacteria were present in clitoral fossa, clitoral sinus, and urethral vestibule, respectively, Sampling during early estrus increased the bacterial isolation rate to 57% in mares that were previously negative; however, 3 days later, CEM bacteria could not be isolated from 62% of the positive mares. The results of repeated exposure experiments indicated the presence of local antibodies, as no CEM bacteria could be recovered at 2, 7, and 15 days after reexposure with a small number of bacterial cells (8.4 x 10(5) cells). The CEM bacteria were isolated from all mares reexposed with a large number of bacterial cells (7.2 x 10(8)) at 2 days after second inoculation and from 50% at 7 days. However, all of the mares were negative by day 15 after reexposure, indicating increased resistance to CEM bacteria.

Characterization of avian reoviruses isolated from the synovia and breast blister.

Reoviruses Texas, S 1133, UMI 203, and WVU 2937 induced swelling of the foot pad and inflammatory changes in the synovial membranes when inoculated in the foot pad of 2-week-old gnotobiotic chicks. From differences in virus neutralization as measured with geometric mean (R) value, all four viruses are subtypes of a single serotype. The cell-associated and cell-released virus growth curves were similar, with a lag phase of about 15 hours and a log phase of 15 to 21 hours. Viral RNA synthesis reached a peak in 5 hours and was active at 14 hours but not at 18 hours. In 90 minutes at 60 C the titer of each virus had decreased about 4 logs.

Susceptibility of mink to certain viral animal diseases foreign to the United States.

Mink (Mustela vison) were inoculated with viruses: African horse sickness (AHS), African swine fever (ASF), bovine herpes virus II (BHV2), foot-and-mouth disease (FMD), goat pox (GP), hog cholera (HC), peste des petits ruminants (PPR), rinderpest (RP), swine vesicular disease (SVD), vesicular exanthema of swine (VES) and vesicular stomatitis (VS). Their susceptibility was measured by development of clinical signs, virus isolation and detection of precipitin and/or virus neutralizing antibodies. SVD virus produced a lesion in one mink. Virus was isolated from mink inoculated with SVD, FMD and BHV2. Neutralizing and/or precipitin antibodies were detected in mink inoculated with ASF, FMD, GP, RP, SVD and VS viruses. Mink were not susceptible to AHS, HC, PPR and VES viruses.

Survival of contagious equine metritis bacteria in transport media.

Survival of bacteria that cause contagious equine metritis (CEM) was evaluated in Amies modified transport (AMT) medium, in AMT medium with charcoal, and in Stuart transport medium at 37, 22, 4, and -70 C. The CEM bacteria suspended in transport media survived at 22, 4, and -70 C for longer periods in AMT medium with charcoal than they did in AMT and Stuart transport media. In 1 day, the number of bacteria in exudate stored in the absence of any transport medium decreased 15-fold at 22 C and twofold at 4 C. The CEM bacteria were isolated from exudate on cotton-tipped swabs from all three transport media at 4 and -70 C on day 10, the termination of the experiment. However at 4 C, the survival of CEM bacteria was greater in AMT medium with charcoal than it was in AMT and Stuart transport media.