Donald R. Mayo

Prevention of transfusion-associated cytomegalovirus infection in neonatal patients by the removal of white cells from blood

The usual methods employed to reduce the risk of transfusion‐associated cytomegalovirus (TA CMV) disease have been to transfuse blood or cellular blood components that are CMV antibody‐negative or to administer deglycerolized frozen red cells. To determine if the reduction of white cells (WBCs) in blood by filtration will also eliminate TA CMV disease in a high‐risk population, 48 surviving very low birth weight (less than 1250 g) neonatal infants born to CMV‐ seronegative mothers at three participating institutions in the Hartford, Connecticut area and receiving at least one CMV‐seropositive blood transfusion were studied. The incidence of TA CMV disease in 26 neonatal patients who received blood prepared by a modified spin‐cool‐ filter technique and in 22 neonatal patients who received blood filtered through a WBC‐reduction filter was compared with the incidence of transfusion‐associated disease in similar populations reported in other studies. The CMV antibody prevalence of the blood donor population was found to be 37 percent. At the time of discharge of the individual neonatal infants in the population studied, and/or 2 to 6 months later, 47 of the 48 who had undergone transfusion had CMV antibody‐negative serologic tests and/or urine culture. The other infant transiently seroconverted because of passive transfer of the antibody. None of the 48 neonatal infants had clinical evidence of CMV infection. This study indicates that WBC reduction of donor blood can reduce and perhaps prevent TA CMV disease in high‐risk neonatal patients.

A phylogenetic approach to following West Nile virus in Connecticut.

The 1999 outbreak of West Nile (WN) virus in the northeastern United States was the first known natural occurrence of this flavivirus in the Western Hemisphere. In 1999 and 2000, 82 independent Connecticut WN virus isolates were cultured from nine species of birds, five species of mosquitoes, and one striped skunk. Nucleotide sequences obtained from these isolates identified 30 genetic changes, compared with WN-NY99, in a 921-nt region of the viral genome beginning at nucleotide position 205 and ending at 1125. This region encodes portions of the nucleocapsid and envelope proteins and includes the entire coding regions for the premembrane and membrane proteins. Amino acid changes occurred at seven loci in six isolates relative to the WN-NY99 strain. Although 34 of the isolates showed sequences identical to the WN-NY99 isolate, we were able to show geographical-based clusters of mutations. In particular, 26 isolates were characterized by mutation of C to T at position 858. This group apparently originated in Stamford, CT and disseminated to sites located as far as 54 miles from Stamford. Sequences of WN virus isolated from both brain and heart tissues from the same avian host were identical in all 14 tested individual birds, suggesting that the mutations we have documented are real and not caused by culture, RNA extraction, or PCR procedures. We conclude that this portion of the viral genome will enable us to follow the geographical and temporal movement of variant WN virus strains as they adapt to North America.

Efficiency of the Ortho VITROS Assay for Detection of Hepatitis C Virus-Specific Antibodies Increased by Elimination of Supplemental Testing of Samples with Very Low Sample-to-Cutoff Ratios

ABSTRACT The clinical significance of specimens with low sample-to-cutoff (S/Co) ratios in the Ortho VITROS chemiluminescence assay (CIA) for detection of antibodies to hepatitis C virus (HCV) was evaluated. In one study of 482 CIA-reactive samples, none of the 83 samples with S/Co ratios of <5 was HCV RNA positive. In a subsequent study, 332 samples with S/Co ratios of between 1 and 20 were tested with the recombinant immunoblot assay (RIBA). None of the 163 samples with S/Co ratios of <5 was RIBA positive, 83% were RIBA negative, and 28 samples (18%) were RIBA indeterminate. HCV RNA and/or clinical evidence of hepatitis was not found in the 27 indeterminate cases examined. These results show that over 99% of samples with very low S/Co ratios (≤5) have no evidence of HCV infection. Therefore, we suggest that the HCV antibody testing algorithm for the VITROS assay might be modified to eliminate supplemental testing of samples with very low S/Co ratios.

Bioterrorism-related Inhalational Anthrax in an Elderly Woman, Connecticut, 2001

On November 20, 2001, inhalational anthrax was confirmed in an elderly woman from rural Connecticut. To determine her exposure source, we conducted an extensive epidemiologic, environmental, and laboratory investigation. Molecular subtyping showed that her isolate was indistinguishable from isolates associated with intentionally contaminated letters. No samples from her home or community yielded Bacillus anthracis, and she received no first-class letters from facilities known to have processed intentionally contaminated letters. Environmental sampling in the regional Connecticut postal facility yielded B. anthracis spores from 4 (31%) of 13 sorting machines. One extensively contaminated machine primarily processes bulk mail. A second machine that does final sorting of bulk mail for her zip code yielded B. anthracis on the column of bins for her carrier route. The evidence suggests she was exposed through a cross-contaminated bulk mail letter. Such cross-contamination of letters and postal facilities has implications for managing the response to future B. anthracis–contaminated mailings.

Inactivation of West Nile Virus during Serologic Testing and Transport

ABSTRACT Inactivation of West Nile virus (WNV) in enzyme-linked immunosorbent assay (ELISA) wash buffer at 37°C was studied, as well as inactivation of WNV in cell culture medium over several days at an ambient temperature (28°C). Aliquots of WNV were removed from the 37°C ELISA wash buffer at 5, 15, 30, and 60 min for the former experiment, while daily aliquots of medium were sampled for the latter experiment. No virus was detected in the wash buffer at 30 and 60 min, while virus was readily detected from cell culture medium over this time. In addition, titers of WNV consistently dropped over a 7-day period at 28°C compared to control suspensions of virus held at 4°C. These observations indicate that WNV is readily inactivated in the presence of detergent-containing buffers. Furthermore, the viability loss at ambient temperature suggests that WNV is easily inactivated during routine transportation and testing of human body fluids such as serum and cerebrospinal fluid.

Cytomegalovirus antibody detection by three commercially available assays and complement fixation

Four methods (complement fixation, latex agglutination, qualitative EIA, and quantitative EIA) for detecting antibody to cytomegalovirus (CMV) were compared by testing 103 sera. When ranked according to accuracy, sensitivity, and specificity, the complement fixation test was third, fourth, and first; the latex agglutination test was first, second, and third; the qualitative EIA was fourth, first, and fourth, whereas the quantitative EIA was second, third, and first, respectively. In addition, the complement fixation, latex agglutination, and quantitative EIA systems each satisfactorily detected significant antibody rises in paired sera.

Role of Chlamydia trachomatis and Mycoplasma pneumoniae in acute pharyngitis in children

In a group of children with acute, nonstreptococcal pharyngitis, only one (2%) of the 44 children tested showed serologic or direct-immunofluorescence evidence of a recent Chlamydia trachomatis infection. Only two (5%) of the 43 children tested showed serologic evidence of a recent Mycoplasma pneumoniae infection. Neither C. trachomatis nor M. pneumoniae appears to be an important cause of acute pharyngitis in children.

Cytomegalovirus antibody detection in blood donors and mothers of very low birth weight neonates by using three serologic methods.

We compared three serologic methods for cytomegalovirus (CMV) antibody detection and determined the CMV antibody seroprevalence of blood donors and mothers of very low birth weight (less than 1250 g) neonates in the Greater Hartford region. CMV serology was determined for 577 healthy blood donors as well as for 147 mothers of premature infants. Plasma from blood donors and sera from mothers were tested by either latex agglutination (LA) or by an immunofluorescent antibody assay (IFA), and results were compared with those from an enzyme-linked immunosorbent assay (ELISA). Sensitivity and specificity for LA to ELISA were significantly better than for IFA to ELISA [sensitivity 79/81 (97%) vs 171/202 (85%), and specificity 90/94 (96%) vs 257/347 (74%), p less than 0.01]. These differences remained whether plasma or sera were tested. Borderline values explained only two (33%) of six LA-ELISA as well as only 70 (58%) of 121 IFA-ELISA discordance. CMV seroprevalence rate for the donor blood population was 38%, and for the mothers was 53%. The LA assay is superior to the IFA assay for CMV screening of blood donors and maternal populations.

Microtiter latex agglutination--quantitative and qualitative equivalent to hemagglutination inhibition for detection of rubella antibody.

Sera were tested for rubella antibody by a standard hemagglutination inhibition method and by latex agglutination in microtiter plates (Virogen Rubella Micro Test). When 157 sera were examined by hemagglutination inhibition and by microtiter latex agglutination for immune status, 149 of the results agreed. The eight discrepant sera (all hemagglutination inhibition-negative, latex agglutination-positive) were tested by a card latex agglutination method (Rubascan) and a passive hemagglutination method (Rubacell). Results, except where noted, agreed with those of the microtiter latex agglutination. One hundred forty-eight of the 149 sera that were in agreement as to immune status were also within a fourfold variation when hemagglutination inhibition and latex agglutination titers were compared. An additional 100 sera were tested for immune status by microtiter latex agglutination and by passive hemagglutination with the single discrepant result agreeing with the latex agglutination when tested by a third method. Both microtiter latex agglutination and hemagglutination inhibition agreed in detection of fourfold or greater rises in each of 20 paired sera.

Effect of 10 minutes heat treatment on HIV antibody testing from alternate testing sites

One hundred and thirty-five sera were tested for the presence of antibody to human immunodeficiency virus (HIV) by enzyme immunoassay (EIA) with the Abbott Diagnostics HTLV-III test before and after heating at 56 degrees C for 10 min. Only one serum specimen was repeatedly reactive after heating when compared with the unheated portion (1/135). The specimen was a low level positive (ratio of test over cutoff = 1.6). Fifty-eight different sera, selected to yield a high percentage of positive results, had both their heated and unheated Western blot (WB) results agree completely with repeated EIA testing. An additional 4,244 sera heated at 56 degrees C for 10 min were tested. Of the 330 repeatable EIA positives, only 38 were not confirmed by WB. HIV infectivity in sera was reduced from 10(3.5) TCID50 to 10(1) TCID50 by the same heat treatment. We conclude that heating sera at 56 degrees C for 10 min significantly reduces HIV infectivity and does not significantly affect the results of HIV antibody testing.