Detection Of Influenza Virus Infection Research Articles

Cardiovascular and renal physiological impacts seen in blood tests of flu diagnosed patients

Early detection of influenza virus infection can potentially reduce risk of morbidity, mortality, and virus transmission through earlier intervention strategies. Although seasonal influenza is a localized respiratory viral infection, changes in cardiovascular physiology and inflammatory biomarkers have been previously observed by our group in mice during influenza infection. Distinguishing patterns among common blood panels, including complete blood count, basic metabolic, comprehensive metabolic, coagulation panel, and c-reactive protein, could lead to earlier diagnosis and better prognosis of symptomatic carriers, but also be useful to diagnose asymptomatic carriers of the virus and provide better infectious disease surveillance. The objective of this study was to utilize the University of Mississippi Medical’s extensive clinical database (EPIC) to investigate the potential association between common blood tests with patients diagnosed with influenza from January 1, 2017 to December 31, 2022. Diagnosed patients were identified from over 1 million patients (of a total population of 3 million) and 36 million encounters of Mississippi residents from the electronic health record Data from patients with reported demographic dimensions (age, first race, and sex), offce visit dimensions (BMI, diastolic blood pressure (BP), pulse rate, respiration rate, systolic BP, and temperature), and common blood test values were obtained for 1896 influenza diagnosed patients, including day of diagnosis and additional encounter visits within 60 days before and after first unique influenza diagnosis. Overall, at day of influenza diagnosis, we see an increase in red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin, hematocrit, estimated glomerular filtration rate (eGFR), aspartate aminotransferase (AST), prothrombin time (PT), and c-reactive protein (CRP) and a decrease in platelets, calcium, glucose, sodium, potassium, bicarbonate, chloride, blood urea nitrogen (BUN), creatinine, albumin, and alkaline phosphatase (AST). Yet, at the sex-specific level, there were differences; females have an increase in glucose, BUN, and creatinine, while males have an increase in albumin and ALP. Multivariate analyses of patients with complete data for 18 blood tests and binned by month relative to the day of diagnosis confirm distinct differences on the day of diagnosis. Future analysis will reveal which blood tests contribute to overall change on the day of diagnosis. Our findings show both changes in cardiovascular and renal physiology during influenza infection and the need to assess these blood measurements during influenza virus infection studies in mice. NIH/NIGMS — 1P20GM144041-01A1 5334 Host-pathogen molecular and cardiovascular interaction during influenza infection. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Detection of influenza virus infections by molecular and immunofluorescence methods

Influenza virus infections are extremely important for human health due to the occurence of seasonal epidemics and pandemics worldwide. Influenza is associated with high morbidity and may result in serious complications such as life threatening viral or bacterial pneumonia. Especially, young children, older adults, patients with chronic diseases such as heart, lung, kidney, and diabetes and immunosuppressed people are at higher risk for complications and death from influenza virus infections. The aim of this study was to determine the incidence of influenza type A and B virus infections and influenza A virus subtypes in hospitalized patients with respiratory tract infections by real-time reverse transcriptase-polymerase chain reaction (RT-PCR, Sacace, Italy), conventional RT-PCR and direct immunofluorescence antibody (DFA, Argene SA, France) tests. Nasopharyngeal swab specimens were collected from a total of 476 patients with respiratory tract symptoms by using flocked swabs (Copan Diagnostics, Italy) between 1 April 2012 and 31 December 2013. Influenza A virus was detected in 20.5% (98/476) and influenza B virus in 3.3% (16/476) of the cases by real-time RT-PCR test. During the study period, 63.3% of 98 influenza virus isolates were found as influenza A(H1N1)pdm09 and 36.7% were influenza A(H3N2) subtypes. Influenza A (H1N1) pdm09 subtype was observed in 12 cases in January 2013 and influenza A(H3N2) subtype was observed in 11 cases in December 2013 as the highest values. When the real-time RT-PCR test was regarded as the reference test, the sensitivities of DFA test for influenza A and B and conventional RT-PCR test with WHO primers (M30F2/08 and M264R3/08) for influenza A were detected as 72.4%, 75%, 96% and the specificities were detected as 99.2%, 99.5% and 100%, respectively. In conclusion, influenza A virus infection was detected rather high with a rate of 20.5% in the study group. The monitoring of influenza virus types and subtypes is required for the evaluation of influenza vaccine strains and circulating influenza viruses and for the identification of subtypes with pandemic potential. Planning for appropriate antiviral therapy using real-time RT-PCR in the early diagnosis of influenza virus infections will significantly contribute to the management of the patient's treatment. Thus, unnecessary drug use will be prevented and controlled with effective treatment of the disease at the time of infection.

The acceptability and validity of self-collected nasal swabs for detection of influenza virus infection among older adults in Thailand.

BackgroundSelf‐collection of nasal swabs could improve the timeliness of influenza virus detection in older adults.ObjectivesMeasure the acceptability, adequacy, timeliness, and validity of self‐collected nasal swabs among adults >65 years in Thailand.MethodsOur evaluation consisted of two parts: a one‐month study among randomly selected, community‐dwelling older adults to simulate community‐based surveillance for acute respiratory infections (ARI); and a clinic study of older adults with ARI to evaluate the sensitivity and specificity of self‐collected nasal swabs for influenza virus infection compared with healthcare worker (HCW)‐collected nasal and nasopharyngeal swabs.ResultsIn the community study, 24% of participants experienced an ARI during the observation period. All (100%) participants with an ARI self‐collected nasal swabs within 72 hours of symptom onset of which 92% were considered adequate samples. In the clinic study, 45% of patients with ARI presented within 72 hours of symptom onset. The sensitivity of self‐collected nasal swabs for detection of influenza virus infection was 78% (95% CI 40‐97) compared to nasopharyngeal and 88% (95% CI 47‐100) compared to nasal swabs collected by HCWs. Specificity was 100% (95% CI 97‐100) compared to both methods. Self‐collection of nasal swabs was found acceptable by 99% of participants in both studies.ConclusionsSelf‐collection of nasal swabs was acceptable to older adults in Thailand who were able to take adequate samples. Self‐collection of nasal swabs may improve the timeliness of sample collection but lower sensitivity will need to be considered.

Results of a pilot study using self-collected mid-turbinate nasal swabs for detection of influenza virus infection among pregnant women.

BackgroundWe evaluated the feasibility of asking pregnant women to self-collect and ship respiratory specimens.MethodsIn a preliminary laboratory study, we compared the RT-PCR cycle threshold (CT) values of influenza A and B viruses incubated at 4 storage temperatures (from 4 to 35°C) for 6 time periods (8, 24, 48, 72, and 168 hours and 30 days), resulting in 24 conditions that were compared to an aliquot tested after standard freezing (−20°C) (baseline condition). In a subsequent pilot study, during January–February, 2014, we delivered respiratory specimen collection kits to 53 pregnant women with a medically attended acute respiratory illness using three delivery methods.ResultsCT values were stable after storage at temperatures <27°C for up to 72 hours for influenza A viruses and 48 hours for influenza B viruses. Of 53 women who received kits during the pilot, 89% collected and shipped nasal swabs as requested. However, 30% (14/47) of the women took over 2 days to collect and ship their specimen. The human control gene, ribonuclease P (RNase P), was detected in 100% of nasal swab specimens. However, the mean CT values for RNase P (26·5, 95% confidence interval [CI] = 26·0–27·1) and for the 8 influenza A virus positives in our pilot (32·2, 95% CI = 28·9–35·5) were significantly higher than the CTs observed in our 2010–2012 study using staff-collected nasal pharyngeal swabs (P-values < 0·01).DiscussionSelf-collection of respiratory specimens is a promising research method, but further research is needed to quantify the sensitivity and specificity of the approach.

Feasibility of real time PCR over cell culture in diagnosis of influenza virus infection: an experience of rade I viral diagnostic laboratory of developing country

Introduction: In spite of the discovery of viral culture technology about a century ago, its application in diagnostic labs is being used since 1970s. It served as the "gold standard" for virus detection for long. In recent years, rapid, technically less challenging, sensitive and highly specific viral identification is possible by molecular tools. Hence, the purpose of this study was to analyze the importance of real time PCR over virus culture in diagnosis of Influenza virus infections, the biggest viral challenge of present India, a developing country, so that prompt and correct diagnosis can help physicians as well as the policy makers to control the virus spread. Objective: To study the feasibility of real time PCR vis a vis viral culture technique and evaluate the utility of these methods for laboratory diagnosis of Influenza virus infections. Methodology: The study was conducted in Grade I Virology Diagnostic laboratory, Dept of Microbiology, KGMU, Lucknow. We used both real time RT-PCR and viral culture methods (on MDCK cell lines) for detection of Influenza virus infection and compared the effect of transport time, cost per sample and turnaround time on both the techniques. Results &amp; Conclusion: Real time PCR is more practical, more sensitive, quicker and cost effective. It needs less expertise and availability of reagents is better. Though viral culture proved to be highly specific and useful for wide application but the use should currently be limited to mostly research facilities. Therefore for epidemiological diagnosis purposes real time PCR detection of Influenza virus is advised.DOI: http://dx.doi.org/10.3126/ijasbt.v2i1.9860Int J Appl Sci Biotechnol, Vol 2(1): 97-102

Immunohistochemical detection of Influenza virus infection in formalin-fixed tissues with anti-H5 monoclonal antibody recognizing FFWTILKP

The worldwide outbreak of avian influenza among poultry species and humans is associated with the H5N1 subtype of avian influenza A virus (AIV). This highlighted the need to develop safe H5 AIV diagnostic methods. 7H10, an H5-specific monoclonal antibody (Mab), can be used for immunohistochemical (IHC) staining for formalin-fixed tissue. An assortment of H5N1 tissue specimens infected naturally in paraffin sections from Asia, between years 2002–2006, including one human specimen, were tested. 7H10 detected H5 infection in all of these tissue samples infected naturally. In addition, 24 different human H5N1 isolates from Indonesia, 5 avian H5 isolates and 3 non-H5 isolates from Asia were inoculated into BALB/C mice and chicken embryos. Among these influenza viruses, 7H10 detected 28 of the 29 H5 virus strains by immunohistochemical staining, while none of non-H5 strains used in this study could be detected by 7H10, confirming its specificity to H5. Further, the eight-residue-long linear epitope, “FFWTILKP”, identified through epitope mapping, enables 7H10 to detect >98.3% of H5 subtype viruses reported worldwide before 2007. This study describes a specific H5 diagnostic system with minimal possibility of exposure to live virus based on immunochemical staining.

Comparative Evaluation of a Rapid Influenza Diagnostic Test in the Pediatric Emergency Department Setting Using Three Specimen Collection Methods

Background: Rapid, accurate, point-of-care detection of influenza virus infection is desirable for the outpatient management of children. Several collection methods including nasopharyngeal wash (NPW), nasopharyngeal swab (NPS) and nasal swab (NS) are available for testing by commercially available rapid influenza diagnostic tests. Unfortunately, the collection of nasopharyngeal specimens by NPW is uncomfortable and time-consuming. Swabs of the nose and pharynx are better tolerated by patients and easier to collect. To date, however, no studies have compared the yield from swabs (NPS and NS) to that from NPW for diagnosing influenza in children. Study Objective: To compare the diagnostic yield of a rapid antigen detection test for influenza in samples obtained by three different specimen collection methods.

Rapid detection of influenza virus infections in human fetal lung diploid cell cultures

Haemadsorbing foci were found in human fetal lung (HFL) diploid cell cultures 12 h after inoculation with influenza viruses A and B. The size and number of the foci were maximal after 48 h of incubation, being limited by production of an unidentified inhibitor. By contrast, inoculation with parainfluenza virus type 3 led to haemadsorption which increased during 10 days of incubation. For the detection of influenza viruses A and B maximum sensitivity was achieved by changing the medium, the day before use to one that was serum free. The number of foci at 15.5 h post-infection and infectivity for primary African green monkey kidney (AGMK) cultures were similar. Virus infectivity and production of haemagglutinin in HFL cells were entirely cell-associated; they were not affected by treatment with trypsin. Nevertheless, influenza viruses A and B antigens were identified in the infected cells by means of immunofluorescence at 15.5 h and virus was recovered by passage of frozen and thawed cells in AGMK cultures. For rapid routine diagnosis of viral infections, the early haemadsorption test was shown to have the same sensitivity as immunofluorescence tests on specimens and virus detection by the shell-vial technique but was cheaper and simpler to perform.