Abstract. 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 ( 1:40) and 54% (205 samples) were positive by VN test ( 1:10), but only 35% (132 samples) were positive by IgM-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; 100. IgM antibodies of EEE virus were monospecific and did not cross-react with western or Venezuelan equine encephalomyelitis viral antigens by the ELISA. Isolation of EEE virus from tissue or detection of IgM antibodies to EEE virus in a single serum sample is evidence of recent EEE infection and differentiated serum from previously vaccinated horses. However, the presence of IgM in the absence of virus isolation could also be due to a recent viral vaccination.Eastern equine encephalomyelitis (EEE) virus is an agnosis of EEE viral infections in humans and chickarthropod-borne virus and belongs to the genus AI-ens. 1,3,9 However, the appearance of IgM antibody in phavirus of the family Togaviridae. The virus infects horses infected with EEE virus has not been defined. horses, humans, and birds and is transmitted by mosThe present work was undertaken to adapt an IgM quitoes of the genera Aedes, Coquillettidia, and Culi-and IgG capture enzyme-linked immunosorbent assay seta.

A polymerase chain reaction (PCR) procedure coupled to an enzyme-linked oligonucleotide sorbent assay (ELOSA; a PCR-ELOSA) identified all 24 serotypic variants of bluetongue virus (BTV) without identifying any of six viruses belonging to the related epizootic hemorrhagic disease virus serogroup. The PCR-ELOSA detected 0.01 50%o cell culture infectious doses of each serotype of BTV. The sensitivity and serogroup-wide specificity of the PCR-ELOSA may enable it to replace the more expensive, time-consuming, and biohazardous methods used in the identification of BTV.

Abstract. The enzootic or endemic strains of Venezuelan equine encephalomyelitis (VEE) virus (ID, IE, IF, and II-VI) are considered avirulent. In 1993 and 1996, outbreaks of encephalitis occurred in the horse populations in the Chiapas and Oaxaca provinces of Mexico, respectively. In both instances, enzootic VEE virus subserotype IE was isolated from brain tissues of dead horses. The present study investigated the pathogenicity of the Chiapas viral isolate (NVSL VEE IE 93-42124) in ponies. Three ponies were inoculated intradermally with 4, 5, and 6 logs, respectively, of the NVSL VEE IE 93-42124 viral isolate. All ponies showed fluctuations in body temperature, encephalitis, and other signs of infection with VEE virus. Virus was isolated only from the blood of ponies from day 1 to day 3 postinfection. Microscopic examination of hematoxylin and eosin-stained tissue sections showed mild to moderate nonsuppurative encephalitis, perivascular cuffing by mononuclear cells, gliosis, and meningoencephalitis. Antibody (IgM) to VEE virus IE was unable to differentiate between various subserotypes of VEE I viruses (serotypes IAB, IC, ID, and IF). Virus neutralizing antibody titers to heterologous VEE I viruses were 10-100-fold less than those for NVSL VEE IE 93-42124 virus and Mena II, a human isolate of VEE IE virus. The study confirmed that NVSL VEE IE 93-42124 virus, which was isolated from a brain of a horse during an outbreak of VEE in Chiapas, Mexico, was pathogenic for ponies.

An 18-month-old male pygmy goat was submitted to the North Dakota State University Veterinary Diagnostic Laboratory for necropsy. It had a generalized seborrheic skin condition and, during the 2 weeks prior to death, had become listless and had been losing body condition.At necropsy, the goat had a generalized seborrheic dermatitis with alopecia. The skin was greasy and had a severe scaly to scabby appearance. The goat was in fair body condition.Microscopic examination of hematoxylin and eosin (HE)-stained skin sections showed marked hyperkeratosis with parakeratosis of the epidermis. There also were numerous extensive foci of polymorphonuclear leukocytes aggregated in the hyperkerototic debris (Fig. 1). A few mononuclear inflammatory cells were sprinkled in the dermis but the major inflammatory changes were confined to the stratum comeum of the epidermis. No ectoparasites or mycotic organisms were detected in the skin sections. The renal corticomedullary junction vasculature showed infiltrates of leukocytes that were predominantly neutrophilic. There also were leukocytic casts and very few randomly scattered oxalate crystals in the medullary tubules. The liver showed mild centrilobular hepatoFrom the

Abstract. Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K 3 and vitamin K 3 in therapy trials indicated that vitamin K 3 was effective in reducing prothrombin times but vitamin K 3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K 3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K 3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40-50 ppm dicumarol) sweet clover. The 45-mg K 3 /kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K 3 /kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K 3 /kg/day group.Sweet clover poisoning is a common livestock problem in the northern plains. It is caused by dicumarol, a fungal metabolite produced from substrates in sweet clover hay. 3,7,9 Despite the potential toxicity of sweet clover, it is still fed to animals in the northern plains as it compares favorably with alfalfa hay in quality, utility, and cost.2 Previously, North Dakota State University investigated the analytical, toxicologic, and treatment aspects of sweet clover poisoning. 1,4 In treatment trials it was observed that vitamin K 3 was not effective, in any form, whereas vitamin K 1 was effective.' A previous report 6 indicated that oral vitamin K 3 might be antagonistic to moldy sweet clover hay. The purpose of this study was to determine if vitamin K 3 would prevent hemorrhagic crises when used as a feed additive with cattle consuming toxic sweet clover hay. Materials and methodsCalves and treatment. Twelve dairy calves weighing 173-235 kg were allotted to 4 separate groups so each group had a similar average weight. All calves were treated with an antibiotic a and a sulfaquinoxaline b prior to the start of the experiment. A number of core specimens were taken from sweet clover bales and analyzed for dicumarol content.5 Based on these values, bales that were considered toxic were ground and mixed to provide equal dicumarol levels to each of the 4 groups. The ground sweet clover was sampled on a bidaily basis to verify the dicumarol levels consumed. Each calf received 1.1 kg/day of concentrate (Table 1) that contained the vitamin K 3 supplement, plus 6.8 kg/day of ground sweet clover. The actual dicumarol levels in the sweet clover were approximately 40-50 ppm and were considered toxic. 4 All animals were fed alfalfa plus the vitamin K 3 feed additive for 10 days before they were started on the toxic sweet clover hay. The vitamin K 3 concentrate was initially supplied as a premix' and was mixed with ground corn and soybean flour (Table 1) to provide vitamin K 3 supplement levels of 0, 0.45, 4.5, and 45 mg vitamin K 3 /kg body weight/day. The compositions of the 4 primary concentrates are described in Table 1. When an 11-mg vitamin K 3 concentrate was later required, the...