Assignment One : Design for Disasters

A day in the life

A victim of H1N1 may contract the virus during their day from any number of sources. Interpersonal communication and infected peoples coughing and sneezing is the main mode of transmission. However contact with infected surfaces can also lead to infection if a person. E.g. receives a handshake or touches and infected surface, and then proceeds to touch eyes, nose or mouth.
Ordinary influenza has a rapid onset, chills, fever, headache, and body temperature rising within a few hours to reach a peak of, 39-40 ℃ or more. It also can be accompanied by sore throat, runny nose, tears, coughing and other respiratory symptoms. In a few cases, there is loss of appetite, abdominal pain, abdominal distension, vomiting and diarrhoea and other gastrointestinal symptoms.
However, H1N1 Influenza in humans can be latent 7 days before showing symptoms. Initially, symptoms are similar to ordinary flu, but suddenly the temperature rises over 39 degrees Celsius, leaving muscle soreness feeling significantly enhanced, accompanied by dizziness, headaches, diarrhoea, vomiting and other symptoms, or part of the symptoms.
After the virus has fully developed and if not treated correctly, other complications may arise in the body. Dehydration happens fast, often through sweats created by the chills which leave the mind in a state of delirium. Common problems such as ear and sinus infections erupt easily creating a lack of equilibrium.
For the very young (1-5) and elderly (60-80) H1N1 can be deadly attacking and exposing their weakend immune systems. Sufferers of Asthma, Lung disease, Blood disease, Endocrine disorder, Liver disorder or Neurological disorders are also at a higher risk of mortality than regular H1N1 victims.

Rationale
H1N1 Test Swab

Background
Swine influenza virus (SIV) is endemic in pigs and their introduction and conversion to highly pathogenic swine influenza virus in domestic livestock is a cause of serious economic losses as well as a risk for potential transmission to humans. The ability to rapidly recognise SIVs in biological specimens is critical for limiting further spread of the disease in live stock and humans. The advent of molecular methods such as real time polymerase chain reaction (PCR) has allowed improvement of detection methods currently used in laboratories.
A number of different laboratory diagnostic tests can be used for detecting the presence of influenza viruses in respiratory specimens, including direct antigen detection tests, virus isolation in cell culture, or detection of influenza-specific RNA by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). These tests differ in their sensitivity and specificity in detecting influenza viruses as well as in their commercial availability, the amount of time needed from specimen collection until results are available, and the tests’ ability to distinguish between different influenza virus types (A versus B) and influenza A subtypes (e.g. novel H1N1 versus seasonal H1N1 versus seasonal H3N2 viruses). Serologic tests on paired acute (within 1 week of illness onset) and convalescent (collected 2-3 weeks later) can help to establish a retrospective diagnosis of influenza virus infection for epidemiological and research studies. However, such serial serological testing is not routinely available through clinical laboratories. At this time, there are only two authorized assays for confirmation of novel influenza A(H1N1) virus infection, including the CDC rRT-PCR Swine Flu Panel assay; however, other rRT-PCR assays such as laboratory developed tests, not approved by FDA, may be able to detect novel influenza A (H1N1) viruses. Public health laboratories in the U.S. are able to perform the CDC rRT-PCR Swine Flu Panel assay. Confirmation of novel influenza A(H1N1) infection may be necessary for surveillance purposes and for special situations, e.g. severely ill patients, patients with immunocompromising conditions, and pregnant and breast feeding women.
Method
Using pernasal nasopharyngeal swab insert test swab through the nares until resistance is met by virtue of contact with the nasopharynx and body of swab reach’s nares. Although a contact time of 30 seconds is advocated, in practice a few seconds of contact often induces coughing or patient resistance, either of which is adequate incentive to remove the swab.
Once swab is removed insert back into tester base and push swab through perforated base into tester fluid. Agitate sample by swirling and leave to stand for 30 minutes. Upon return sample should change colour to reveal positive or negative result.
The procedure follows the general principle of polymerase chain reaction; its key feature is that the amplified DNA is detected as the reaction progresses in real time, a new approach compared to standard PCR, where the product of the reaction is detected at its end. Two common methods for detection of products in real-time PCR are: (1) non-specific fluorescent dyes that intercalate with any double-stranded DNA, and (2) sequence-specific DNA probes consisting of oligonucleotides that are labelled with a fluorescent reporter which permits detection only after hybridization of the probe with its complementary DNA target.
In molecular biology, real-time polymerase chain reaction, also called quantitative real time polymerase chain reaction (Q-PCR/qPCR) or kinetic polymerase chain reaction is used to amplify and simultaneously quantify a targeted DNA molecule. It enables both detection and quantification of one or more specific sequences in a DNA sample.
Real-time PCR using double-stranded DNA dyes
A DNA-binding dye binds to all double-stranded (ds) DNA in PCR, causing fluorescence of the dye. An increase in DNA product during PCR therefore leads to an increase in fluorescence intensity and is measured at each cycle, thus allowing DNA concentrations to be quantified.
Like other real-time PCR methods, the values obtained do not have absolute units associated with it (i.e. mRNA copies/cell). As described above, a comparison of a measured DNA/RNA sample to a standard dilution will only give a fraction or ratio of the sample relative to the standard, allowing relative comparisons between different tissues or experimental conditions. To ensure accuracy in the quantification, it will be necessary to normalize expression of the target gene novel Influenza A to stably expressed the gene.
Rapid Influenza Diagnostic Test
The Rapid influenza diagnostic test (RIDTs) is an antigen detection test that detects the influenza viral nucleoprotein antigen. On collection and testing of DNA sample, the test can provide results within 30 minutes or less. Thus, results are available in a clinically relevant time period to inform clinical decisions. These assays may be referred to as “point-of care” tests.
Few comparisons of RIDTs with RT-PCR for the detection of novel influenza A (H1N1) virus or seasonal influenza viruses have been published. Three recent analytical studies indicate that commercially available RIDTs are reactive with the nucleoprotein of novel influenza A (H1N1) virus.

The Role of RIDT for Detecting Novel H1N1: Clinical Considerations
A RIDT may provide useful response information that might impact on patient care, therefore easing hospital congestion and lowering public panic through rapid diagnosis. However, understanding the limitations of RIDTs is very important to appropriately interpret results for clinical management. When influenza viruses are circulating in a community, a positive test result indicates that influenza virus infection is likely present in the specimen. Knowledge of the presence of influenza A or B virus infection can help to inform influenza treatment decisions. However, a negative rapid test result does not rule out influenza virus infection. Since false negative results can occur, if clinical suspicion of influenza is high in a patient who tests negative by RIDT (or if RIDT is not offered), empiric antiviral therapy should be administered, if appropriate, and infection control measures implemented.
Construction
The body of the test swab is constructed with a two piece polycarbonate injection moulding. This material and method have been selected for its ability create detail and maintain strength. The tamper evident clip relies on a styrene injection moulding which have planned points which fail upon opening to alert user of use and contamination. The pernasal nasopharyngeal swab is a polycarbonate extrusion with a Dacron swab head attached.


Glossary

Assay - a procedure in molecular biology for testing and/or measuring the activity of a drug or biochemical in an organism or organic sample.
Antigen - a molecule recognized by the immune system. Originally the term came from antibody generator and was a molecule that binds specifically to an antibody, but the term now also refers to any molecule or molecular fragment that can be bound by a major histocompatibility complex (MHC) and presented to a T-cell receptor]. "Self" antigens are usually tolerated by the immune system; whereas "Non-self" antigens are identified as intruders and attacked by the immune system. Autoimmune disorders arise from the immune system reacting to its own antigens.

Nares - Nostrils
PCR - Polymerase chain reaction
RIDT - Rapid Influenza Diagnostic Test
rRT-PCR - Real-time polymerase chain reaction