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The utility of using Nobuto paper strips for the detection of avian influenza antibodies was examined in mallards (Anas platyrhynchos) experimentally infected with low pathogenic avian influenza viruses. Blood was collected 2 wk after infection and was preserved either as serum or whole blood absorbed onto Nobuto strips. Analysis of samples using a commercially available blocking enzyme-linked immunosorbent assay revealed comparable results (> or = 96% sensitivity for all methods) between sera stored at -30 C and the Nobuto strip preservation method even when the Nobuto strips were stored up to 3 mo at room temperature (RT). Significant differences were detected in the ratio of sample absorbance to negative control absorbance for Nobuto strips stored at RT compared with sera stored at -30 C, although these differences did not affect the ability of the test to reliably detect positive and negative samples. Nobuto strips are a convenient and sensitive alternative to the collection of serum samples when maintaining appropriate storage temperatures is difficult.

The feasibility of using liver impressions on Flinders Technology Associates (FTA filter paper for the collection, inactivation, and molecular analysis of fowl adenovirus (FAV) was evaluated. FAV I European Union (EU) serotype 1 spotted on FTA was shown to be inactivated using specific-pathogen-free (SPF) primary chicken embryo liver cell culture as indicated by absence of cytopathic effect. Sensitivity of the polymerase chain reaction (PCR) test using tenfold dilutions of allantoic fluid from 100 to 10-4 for the detection of adenovirus serotype 1 on FTA cards was determined to be 0.0005 mean tissue culture infectious dose per FTA spot. The stability of the DNA from liver impressions on the FTA was found to be 198 days when stored at -20 degrees C. In a trial, inclusion body hepatitis (IBH) was experimentally reproduced in SPF chickens inoculated with FAV I EU serogroup 1, 4, 8, or 11, which presented weakness, pallor, depression, dehydration, and mortality within 6 days after inoculation. PCR performed on FTA liver impressions from the inoculated birds was able to detect all four viruses, and the nucleotide sequence analysis of the amplified PCR products (1219 bp of the hexone gene) revealed the expected serotypes. In addition to the trial, 55 clinical samples were analyzed from liver impressions on FTA cards, and FAV was detected in 11 of 55 (20%). Sequencing analysis showed that the viruses were EU serotypes 4, 5, 9, and 10. The results demonstrate that FTA filter paper inactivates the FAV I and maintains the DNA template for molecular analysis.

A practical sampling method for bursal tissue using ordinary paper for molecular diagnosis of infectious bursal disease (IBD) was established. IBD virus-infected bursa was directly smeared on chromatography paper, filter paper, or stationery copy paper and was then fixed with absolute ethanol, Tris-HCl-saturated phenol, or phenol:chloroform:isoamyl alcohol (25:24:1). Flinders Technology Associates (FTA) card, which is designed for the collection of biological samples for molecular detection, was also used. After storage at 37 C for up to 30 days, total RNA directly extracted from the tissue fixed on the papers and FTA card were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of IBD virus (IBDV) RNA. In addition, the ability of each chemical used in the fixation and the FTA card to inactivate IBDV was evaluated. Regardless of the paper quality, storage period, and fixation method, IBDV RNA was consistently detected in all of the samples. IBDV in the bursal tissue was inactivated with phenol but not with ethanol or the unknown chemicals in FTA card. These results show that ordinary papers sustain the viral RNA, as does FTA card, but phenol fixation is superior to FTA card in inactivating IBDV. The new sampling method using ordinary paper with phenol fixation is safe, inexpensive, simple, and easy, and is thus suitable for conducting a global survey of IBD even where laboratory resources are limited. This practical method should contribute to the control of IBD worldwide.

We investigated the feasibility of using FTA filter cards for the storage of bursas of Fabricius containing infectious bursal disease virus (IBDV) and for IBDV detection by reverse transcriptase (RT)-polymerase chain reaction (PCR), and characterization by restriction fragment length polymorphism (RFLP) or nucleotide sequencing. The FTA card is a cotton-based cellulose membrane containing lyophilized chemicals that lyses many types of bacteria and viruses. IBDV was inactivated upon contact with the FTA as shown by the inability of the virus to be propagated in embryonating chicken eggs. Viral RNA in minced bursas or stamped bursas could be amplified by RT-PCR (VP2 gene fragment, 248 base pairs) after storage on FTA for at least 15 days at room temperature or 8 mo at -20 C. Analytical sensitivity of the test was between 0.5-5 ng of RNA template or 5 x 10(1) mean tissue culture infective dose (TCID50)/FTA spot. Detection rate of IBDV in domestic clinical samples collected on FTA or collected by the non-FTA standard procedure was 36.7% and 41.7%, respectively, which represents 88% agreement. Detection of IBDV from FTA cards inoculated with bursal tissues in the laboratory or in the field was 36.7% and 37.1%, respectively. Detection of IBDV from FTA samples when the cards were inoculated with bursal tissues and sent through customs into the United States was 32.9%. Analysis of the amplified products showed that molecular characterization of IBDV by RFLP or nucleotide sequencing is feasible in bursas stored on FTA at 25 C for 1-3 mo or at -20 C for at least 8 mo. The use of FTA for the collection of bursal tissues and simultaneous inactivation of IBDV allows the movement of specimens within the United States and also from outside the United States in compliance with federal regulations and in a manner adequate for molecular characterization.

We investigated the feasibility of using Flinders Technology Associates (FTA) filter cards for the storage of allantoic fluid containing an infectious bronchitis virus (IBV), such as Arkansas-DPI, Connecticut, and Massachusetts, and for their identification by reverse transcriptase (RT)-polymerase chain reaction (PCR) and characterization by restriction fragment length polymorphism (RFLP) or nucleotide sequencing. FTA paper is a cotton-based cellulose membrane containing lyophilized chemicals that lyses many types of bacteria and viruses. IBV was inactivated upon contact with the FTA, as shown by the inability of the virus to be propagated in embryonating chicken eggs. RT-PCR of the S1 gene showed that viral RNA in allantoic fluid remained stable after storage on FTA filter cards and that the stability was time and temperature sensitive for the large (1700 base pair [bp]) but not the small (383 bp) PCR products. Analysis of the amplified products showed that molecular characterization is feasible in allantoic fluid stored on FTA under nonfavorable environmental conditions (41 C) for at least 15 days. The use of FTA cards for the collection, transport, and storage of IBV-containing samples is safe, inexpensive, and adequate for molecular diagnosis. We propose that specimens coming from overseas on FTA cards would be first analyzed by RT-PCR with primers yielding a 1700-bp product followed by RFLP of the positive cases. Negative cases would be analyzed with primers yielding a 383-bp product (to exdude detrimental effect of the storage conditions) followed by nucleotide sequencing of the positive cases.

We evaluated the feasibility of using Flinders Technology Associates (FTA) filter paper for the inactivation and storage of mycoplasma DNA templates and their detection by the polymerase chain reaction (PCR). FTA paper is a cotton-based cellulose membrane containing lyophilized chemicals that lyses most types of bacteria and viruses. Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) cultures were spotted at various volumes on the filter paper and stored at different temperatures for various periods of time before performing PCR. MG and MS were readily detected at all time frames (1-60 days) independent of the volume applied (1-100 microl) or storage temperature (4 C-41 C). Sensitivity and specificity of the FTA-PCR were comparable to the standard diagnostic PCR, allowing the detection of MG/MS in field samples without interference by nontargeted mycoplasma. Analysis of 193 field samples by both methods showed nearly 100% agreement with serology and culture results. The long-term DNA stability at a wide range of temperatures makes the FTA cards a good alternative for collecting and simultaneously inactivating mycoplasma. It also offers the convenience of storage and transport of DNA in a cost-effective manner for further molecular analysis, such as restriction enzyme length polymorphism and nucleotide sequencing.

Common Whatman filter paper grade 1 and nitrocellulose membrane were compared for their sensitivity in a dot-immunobinding assay for detection of serum antibody titers to Arkansas avian infectious bronchitis virus (AIBV). For a blue to purple color detection, serum antibodies were bound to AIBV antigen adsorbed on the filter-paper discs or nitrocellulose membrane. Rabbit anti-chicken IgG horseradish-peroxidase (HRP) conjugate and hydrogen peroxide with 4-chloro-1-naphthol (HRP-color development reagent) were applied. The study indicates that very small amounts of antigen/antisera are needed for the dot-immunobinding assay. The test is sensitive, economical, and easy to run and can be completed within 6-8 hours.

Two methods for collecting blood for measuring antibody activity of Pasteurella multocida were compared. Whole blood was collected on filter-paper strips, dried for 48 hr at room temperature, and then stored in sealed plastic bags at 4 C. Blood was also collected in the usual manner with a needle and syringe, and serum was harvested and stored at -20 C until tested. Eluates of whole blood, obtained by overnight elution of two 4.8-mm discs in 200 microliters of buffered saline at 4 C, were compared with conventionally harvested serum for antibody activity by enzyme-linked immunosorbent assay (ELISA). Paired samples, taken from the same bird at the same time, showed no significant difference (P less than 0.05) in antibody activity as measured by absorbance when the disc-elution process itself was considered to be a 1:20 dilution. It was concluded that eluates of blood, derived from whole blood dried on filter-paper strips, may be used as an alternative to sera in ELISA for measuring P. multocida antibody activity.