Detection of eastern equine encephalomyelitis virus and Highlands J virus antigens within mosquito pools by enzyme immunoassay (EIA). II. Retrospective field test of the EIA.

Enzyme immunoassays (EIAs) for eastern equine encephalomyelitis (EEE) and Highlands J (HJ) virus antigens were compared in a retrospective study with standard virus isolation procedures (VIP) for detection of alpha virus-infected mosquito pools. The original VIP was a plaque assay in chick embryo cell culture, and was performed in the years from 1979 to 1981. Using the original VIP as the reference standard, the sensitivity rate of the EIA was 0.7674 and the false negative rate was 0.2326. However, when the storage age and the initial virus titer of the sample were considered, the sensitivity rate increased. For samples containing greater than 1,500 plaque-forming units (PFU) per ml of virus during the original VIP, the sensitivity rate of the EIA was 0.97; but the rate declined to 0.14 for those originally containing less than 500 PFU per ml. Most of the false negatives (68%) occurred with samples containing less than 500 PFU per ml. Presumably the low quantities of virus in these 50 pools were lost during storage and handling; virus was obtained from only 16% (8/50) during reisolation attempts using BHK-21 cells. Specificity of the EIA was excellent; no false positive results were obtained and serological identification was identical to that determined by plaque reduction neutralization in greater than 98% of the pools examined. Characteristics of the pools, such as pool size, species of mosquitoes, or gravidity did not affect the EIA results. These studies support the use of EIAs in surveillance programs attempting to determine infection rates of known arboviruses in vector populations.

The prediction of healing in ischemic lesions of the foot. A comparison of Doppler ultrasound and elevation reactive hyperemia.

The results of the Elevation Reactive Hyperemia Test (ERHT) and the transcutaneous Doppler ultrasound ankle blood pressure (DAP) have been compared in a series of 115 cases with ischemic lesions of the foot. The ERHT was carried out by simple elevation of the foot or elevation with the circulation temporarily obstructed by a blood pressure cuff following which the foot was gradually lowered until the reactive hyperemia was seen in the skin and the height above the right atrium was estimated. The appearance of the hyperemia at 35 cm above the right atrium will allow healing of local ischemic lesions and at the height of 45 cm or above indicates a zone at which amputation may be carried out successfully. In the same series the DAP using 60 mmHg as the cut off point showed 40% healing with a pressure less than this level and 40% failed with a pressure above this level. The DAP gave no consistent prediction of the healing of ischemic lesions or of amputations.

Antibodies to Borrelia burgdorferi in New England horses: serologic survey.

Twelve of 50 randomly selected horses from areas endemic for Borrelia burgdorferi had indirect fluorescent antibody titers of 1:8 to 1:2,048 against B burgdorferi. One of 50 horses from nonendemic areas had a titer of 1:8. This difference in the number of horses seropositive for B burgdorferi (P less than 0.002) and our finding that seropositive horses did not have agglutinating antibodies against potentially cross-reacting Leptospira spp indicated that horses in endemic areas were exposed to B burgdorferi and that the spirochete induced an antibody response in the horses.

Single-radial hemolysis as a cost-effective determinant of Rubella antibody status.

Single-radial hemolysis was examined for sensitivity, reliability, and cost for determination of rubella antibody levels in the general population. Results obtained with single-radial hemolysis plates made in this laboratory, and those under development by a commercial manufacturer, were compared with those obtained by the hemagglutination inhibition method normally used for rubella antibody determinations. The results suggest that single-radial hemolysis is comparable to hemagglutination inhibition with respect to sensitivity and reliability; it is superior to hemagglutination inhibition in terms of ease of manipulation and economy of use.

Relation of Mycoplasma pneumoniae seroreactivity, immunosuppression, and chronic disease to Legionnaires' disease. A twelve-month prospective study of sporadic cases in Massachusetts.

From April 1977 through March 1978, 28 presumptive cases of Legionnaires' disease were identified among 432 consecutive candidates having paired sera or tissue samples submitted to the Massachusetts Public Health Laboratories. Among the subgroup of 209 candidates with documented diffuse pneumonia and temperature of 39 degrees C or above, 24 (11.5%) had Legionnaires' disease whereas the diagnostic yield was only four of 223 (1.8%) among the remainder. The case-fatality rate was two of 28 (7%). Patients with Legionnaires' disease when compared to the entire group of candidates were similar in mean age (49 versus 48 years) and frequency of immunosuppressant therapy (15% versus 12%) but were more often male (64% versus 47%) with underlying chronic illness (46% versus 22%). Complement fixation tests against Mycoplasma pneumoniae (whole organisms) showed seroreactivity in 81% of Legionnaires' disease (LD) cases (22 to 27) compared to 13% of non-LD cases; conversely, 29% of all cases seropositive for M. pneumoniae (22 of 75) were seropositive for the LD bacterium compared to only 1% (five of 357) of the remainder. The coincidence of seroreactivity for M. pneumoniae and the LD bacterium is unexplained but suggests that M. pneumoniae seropositive cases should be evaluated for the possibility of Legionnaires' disease.

Needlepoint teeth for jaws of vascular surgical clamps.

A vascular surgical clamp is described which has a single row of needlepoint teeth for the jaws. In our experience, the use of fine round and pointed teeth seems to afford less trauma and greater control of the vessel.

Influenzal vaccine response in systemic lupus erythematosus.

The response of patients with systemic lupus erythematosus and normal subjects to systemic immunization and boosting with influenza A vaccines was studied. Symptoms after vaccination were somewhat more frequent in the patients than in the normal subjects; however, all symptoms were minor and no major flare of illness occurred. No significant induction or increase of pre-existing autoantibodies among the patients was detected after vaccination. The immunogenecity of the vaccinations, as assessed by antibody titers, was similar in the patient and control groups. No correlation between serologic response to influenzal antigens and HLA was found. Thus, in this group of patients with systemic lupus erythematosus, who were either in remission or had mild-to-moderate disease activity, killed influenzal vaccination caused no apparent worsening of disease activity.

Epstein-Barr virus in normal pregnant women.

Acquired immune suppression accompanying normal pregnancy may be associated with reactivation of Epstein-Barr virus (EBV). Pregnant women with reactivated EBV having anti-EA antibodies show high titers of antiviral capsid antigen (VCA) geometric mean titers (GMT) of 522 versus 170 in those lacking anti-early antigen (EA). Among twenty-seven seropositive women at parturition, 17 (63%) had generated antibody to EA, and all 27 (100%) demonstrated significant increases in antibody to VCA (p less than 0.01). In contrast, antibody titers to cytomegalovirus, herpes hominis, varicella-zoster, and rubella viruses in the pregnant women were comparable to those found in nonpregnant controls. (Am J Reprod Immunol. 1982; 2:217-221.)

Eastern equine encephalitis in Massachusetts, 1957-1976. A prospective study centered upon analyses of mosquitoes.

Reappearance of eastern equine encephalitis (EEE) in Massachusetts residents in the 1970's provided an opportunity to assess the predictive value of data on rainfall, EEE in horses, and carriage of EEE virus (EEEV) by mosquitoes, factors which had been studied annually since the last EEE outbreak in 1955-1956. The cycle of multiple cases during 1973-1975 started in a second consecutive year of rainfall that exceeded the annual mean by more than 20 cm, conditions recapitulating the 1955-1956 experience. In 1973, widespread EEE fatalities in horses presaged human cases, another recapitulation of the 1955-1956 experience. However, in 1974, when horses were immunized extensively, no equine cases were seen even though three human fatalities occurred. An unseasonably early appearance of EEEV in mosquitoes was the only basis upon which the threat to humans could have been recognized. These changes in the recognition and distribution of EEEV activity from season to season illustrate the difficulty in making rational decisions regarding widespread aerial insecticide applications for mosquito control.

Kawasaki syndrome: description of two outbreaks in the United States.

Investigation of two outbreaks of Kawasaki syndrome (KS) in the United States in 1979 and in 1980 revealed no evidence of person-to-person transmission or of a common-source exposure among patients. Questionnaire data showed that KS was more likely to occur in children of middle and upper socioeconomic status than in those of lower status (P less than 0.05 and P less than 0.001 for the respective outbreaks) and that patients with KS had a higher incidence of an antecedent, primarily respiratory illness than did controls matched for age, sex, and race (83% of patients in the first outbreak vs. 30% of one control group, P less than 0.01, and vs. 36% of another control group, P less than 0.02; and 56% of patients in the second outbreak vs. 32% of their controls, P less than 0.02). However, laboratory studies did not identify an etiologic agent for either KS or for the antecedent illness that may be a risk factor for KS.