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How To Diagnose Viral Infection

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Symptoms Of Viral Infection

How to Treat a Viral Infection

Viral infection can be a mild or a severe condition. If you have a viral infection in your body, it will cause certain symptoms to appear. These symptoms are the key indicators for recognizing whether you have a viral infection in your body or not. The most common viral infections are the common cold and flu. Both of them lead to a range of symptoms, including headache, fever, cough, sore throat, runny nose, etc. Here is a list of common symptoms that indicate the presence of a viral infection:

The common symptoms of viral infection are:

1. You get tired easily.

2. You feel unwell and lethargic during the day.

3. You have a lot of fever and chills.

4. Your appetite decreases and you experience digestive problems.

5. You experience headaches, muscle and joint pains and body aches in general.

6. Your immune system becomes weak and you fail to fight infections well.

You have to be careful when youre exposed to a virus. Most of the time, it wont even show up. Some of them are so subtle that you dont experience any symptoms at all. But there are some viruses that will attack so quickly, so forcefully, and with such intensity that you will feel like the world is on fire. It feels like youre dying, like it cant get any worse.

Virus Or Bacterium Rapid Test Pinpoints Infections Cause

A generation of new tests could lessen overuse of antibiotics

Runny nose, cough, fever: patients show up in clinics every day with these classic symptoms of respiratory infection. But is the culprit a bacterium, which can be attacked with antibiotics, or a virus, which is harder to target with medication? Often doctors cannot be certain. But researchers say they are closing in on an accurate test that can make the call quickly, right in a physicians office.

Faced with an unknown infection, doctors sometimes order laboratory tests for common bacteria such as Streptococcus. Or they might immediately try antibiotics, basing this decision simply on symptom strengthbut antibiotic overuse can lead to dangerously resistant bacterial strains. When the distinction can be made quickly, we can ensure that antibiotics are not inappropriately prescribed, says Duke University infectious disease specialist Ephraim Tsalik. In 2016 he and his colleagues developed a lab test linking common respiratory symptoms to viral, bacterial or noninfectious origins. It works because each pathogen activates a different set of genes, varying their RNA or protein production, and the test can spot these telltale gene expression signatures in a small blood sample.

This article was originally published with the title “Virus or Bacterium?” in Scientific American 325, 2, 18


What Are The Different Types Of Viral Infections

The most common type of virus led infection is the Respiratory Infection.

Respiratory infection affects the throat, upper airways and lungs. Most common respiratory infection includes a sore throat, common cold, sinus, pneumonia and influenza. Respiratory infection causes a lot of troubles in infants, older people and people suffering from lung or heart disorder.

Apart from respiratory infection, these can affect other specific parts/organs of the human body:

  • Liver: The presence of virus in liver can result in Hepatitis
  • Gastrointestinal tract: The existence of virus in the gastrointestinal tract, like gastroenteritis, is usually caused by rotavirus and norovirus.
  • Nervous System: Certain viruses like rabies virus and west nile virus infect human brain and cause encephalitis. There are some other viruses as well that infect the tissue layer covering the brain and spinal cord. These can cause meningitis.
  • Skin: There are some kind of viruses that cause skin infection which result in blemishes or warts. Many viruses that affect other body organs/parts, like chickenpox can cause rashes on the skin.

What diseases are caused by viruses?

Many human diseases are caused by virus led infections. These include:

  • Smallpox
  • Sleepiness
  • Confusion

When is a Viral Infection serious?

  • Complaints and symptoms lasting for more than seven days
  • High fever lasting for more than five days
  • Breathlessness
  • New reddish rash or spots on the body

Bodyâs defense against Viral Infection

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S Used In Diagnostic Virology

Viral isolation and a number of methods for detection of viral antigens, nucleic acids, and antibodies are the core repertoire of techniques used for the laboratory diagnosis of viral infections, although some other techniques are also occasionally used . Viral isolation by means of cell culture is virtually always performed in designated virology laboratories. The other methods may be performed in those laboratories as well but may also be performed in diverse laboratory sections such as general microbiology, serology, blood bank, clinical chemistry, pathology, or molecular virology. The trend for viral diagnostic testing to be done outside of traditional virology laboratories is likely to accelerate as rapid diagnostic techniques based on immunologic and nucleic acid methodologies increasingly replace viral culture.

The shell vial culture method, first developed for CMV , dramatically decreases the time required for detection of viruses in cell culture. The method involves centrifugation of the specimen onto the cell culture monolayer and incubation for 12 days, followed by fluorescent antibody staining of the cell culture, regardless of whether CPE is visible. In addition to detection of CMV, shell vial cultures have also been used to speed the detection of HSV, VZV, respiratory viruses, and the enteroviruses.

Prevention Of Viral Infections

Bacteria VS. Viruses

Prevention of viral infections may include

Vaccines and immune globulins help the body better defend itself against diseases caused by certain viruses . The process of strengthening the body’s defenses is called immunization Overview of Immunization Immunization enables the body to better defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by certain… read more .

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How Is A Viral Fever Diagnosed

Both viral and bacterial infections often cause similar symptoms. To diagnose a viral fever, a doctor will likely start by ruling out a bacterial infection. They can do this by considering your symptoms and medical history, as well as taking any samples to test for bacteria.

If you have a sore throat, for example, they might swab your throat to test for bacteria that causes strep throat. If the sample comes back negative, you likely have a viral infection.

They can also take a sample of blood or other bodily fluid to check for certain markers that might indicate a viral infection, such as your white blood cell count.

In most cases, viral fevers dont require any specific treatment. Unlike bacterial infections, they dont respond to antibiotics.

Instead, treatment usually focuses on providing relief from your symptoms. Common treatment methods include:

  • taking over-the-counter fever reducers, such as acetaminophen or ibuprofen, to reduce a fever and its symptoms
  • resting as much as possible
  • drinking plenty of fluids to stay hydrated and replenish fluids lost while sweating
  • taking antiviral medications, such as oseltamivir phosphate , when applicable
  • sitting in a lukewarm bath to bring your body temperature down

Quick Test To Diagnose Bacterial Or Viral Infection

American Associates, Ben-Gurion University of the Negev
Treating viral infections with antibiotics is ineffective and contributes to the development of antibiotic resistance, allergic reactions, toxicity and greater health care costs, researchers say. Currently tests take 24-48 hours and aren’t always accurate enough for a clear-cut diagnosis. A new accurate and time-saving method has just been developed.

Researchers at Ben-Gurion University of the Negev have developed a new test that quickly and accurately distinguishes between bacterial and viral infections in as little as five hours.

Treating viral infections with antibiotics is ineffective and contributes to the development of antibiotic resistance, allergic reactions, toxicity and greater healthcare costs. Currently tests take 24-48 hours and aren’t always accurate enough for a clear-cut diagnosis. Doctors often prescribe antibiotics to provide patient relief before the test comes back, without waiting for the results.

According to a study published in the Journal of Analytical Chemistry, the BGU group has shown it is possible to distinguish a patient’s infection as either viral or bacterial by adding luminol to a blood sample and measuring the glow. Luminol is a luminescent chemical substance used in crime scenes to locate traces of blood.

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Detection Of Viral Nucleic Acids

Nucleic acid detection is now widely applied by use of polymerase chain reaction assays, combined with advances in oligonucleotide synthesis, standardized automated procedures for nucleic acid extraction, and real-time detection of PCR products. Rapid advances in nucleic acid sequencing technology and the availability of sequence databases have greatly enhanced analysis of the results obtained. Isothermal RNA and DNA amplification assays are also readily available. Signal amplification assays were used previously but have been superseded.

Nucleic Acid Hybridization

From the time of the development of the first nucleic acid hybridization techniques, a variety of test formats were applied to viral nucleic acid detection. Early approaches usually involved a hybridization reaction between an immobilized nucleic acid target and a labeled probe, washing away unbound probe, followed by subsequent detection of bound probe. These include dot-blot assays using nucleic acid-containing samples immobilized onto filters Southern blot hybridization, where viral nucleic acids are separated by electrophoresis according to molecular weight, blotted to a filter and detected by hybridization and in situ hybridization applied to infected tissue sections or exfoliated cells. Real-time PCRs nowadays often use hybridization in solution as part of the product detection strategy.

Polymerase Chain Reaction

Microarray Technologies

Next-Generation Deep Sequencing

How Are Viral Infections Diagnosed

How to Treat a Viral Infection

Usually your doctor can diagnose a viral infection simply by noting your symptoms. Sore throat, coughing, and a runny nose are all commonly caused by viruses that infect your upper respiratory system. If there is a flu going around your doctor will note the symptoms that are common for that particular type of influenza and diagnose it based on those findings. Cultures may be taken from secretions, or your doctor might take a blood test to determine what type of virus has infected your body.

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Treatment Options And Prevention For Viral Throat Infection

Most causes of viral throat infections will resolve on their own without a specific antiviral treatment, especially in otherwise healthy individuals. Therefore, most treatment is focused on improving symptoms until the infection clears, including rest and hydration, soothing measures and pain medication, environmental changes and specific antiviral treatment.

Some Steps You Can Take

Whether your sinus infection turns out to be viral or bacterial, you can help to ease your symptoms early on with supportive sinus care:

  • Use saline spray two to three times per day in each nostril.
  • Use a nasal decongestant such as Afrin®, but not longer than three days.
  • Drink eight 8-ounce glasses of fluid per day.
  • Get plenty of rest.
  • Take an over-the-counter anti-inflammatory, such as acetaminophen or ibuprofen to help relieve the swelling of your sinuses.
  • If your symptoms arent improving after one week, its important to see your doctor. If a bacterial infection is suspected, youll probably need to take an antibiotic to clear up the infection and prevent further complications.

    If your infections occur more frequently, and your doctor really wants to establish if they are bacterial or viral, your Otolaryngologist or ear, nose and throat doctor can sample the snot from your nose when youre infected and send it to a laboratory to know for sure.

    Note: Antibiotics wont help a viral infection, and taking an antibiotic unnecessarily can do more harm than good. You risk possible side effects and increase your chances of developing antibiotic resistance, which can make future infections harder to treat, says Dr. Sindwani. So its important to wait and see how long your symptoms last.

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    Rationale For Specific Viral Diagnosis

    Historically, diagnostic virology has had to justify its use. The reasons have been that traditional viral diagnostic techniques, especially culture, are slow, expensive, and often peripheral to clinical decision-making, particularly when no therapeutic agents are available. The availability of antiviral therapeutic agents such as acyclovir, ganciclovir, foscarnet, cidofovir, antiretroviral drugs, neuraminidase inhibitors, and IFN- that are effective for specific viral infections but expensive has created an obvious need for specific viral diagnosis.

    In some cases, establishing a specific viral diagnosis limits other diagnostic procedures and may allow discontinuation of antibiotic therapy . Likewise, in some cases, confirmation of a specific viral diagnosis helps in determining prognosis. A recent study of diagnostic testing for respiratory syncytial virus documented that physicians usually believed that rapid test results influenced their management of cases . Rapid RSV testing has also been used as the basis for patient placement to limit nosocomial transmission . Finally, viral diagnosis may be important for public health purposes. For example, laboratory documentation of cases of rubella or rubeola can set in motion extensive vaccination campaigns.

    Serological Procedure For The Laboratory Diagnosis Of Viruses

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    • A rise in antibody titre to the virus can be used to diagnose viral infection. A serum sample is obtained in the acute phase , and a second sample is obtained in the convalescent phase . If the antibody titre in the convalescent phase serum sample is at least 4 fold higher than the titre in the acute phase serum sample, the patient is considered to be infected.
    • In some viral disease for which cutoff titre is known, patient showing rise in antibody titre than cut off value can be considered as infected and
    • in other viral disease the presence of IgM antibody is the diagnostic. Primary antibody response is governed by IgM .

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    Direct Identification Of Virus Viral Antigen Or Viral Genome

    Direct detection of virus material in a patient sample has become the method of choice for a very large number of different infections. These methods have the advantage of speed, as they do not rely on virus culture or a rise in antibody titer. The sensitivity and specificity of antigen detection methods have increased greatly through use of high-quality reagents and solid phase reagent supports allowing ease of washing and signal detection the sensitivity of nucleic acid detection has advanced from early dot blot and Southern blot assays to the widespread and reliable use of PCR.

    What Is Viral Infection

    Viruses are present in almost every ecosystem on earth. They are marked as the most abundant biological entity on this planet. But sometimes these largely present entities cause trouble in human body. Viral Infection is one of the most common ailments affecting people. In simple parlance, a disease that is/can be caused by different types of virus is known as Viral Infection. It can affect various parts of the human body. It is observed that some viruses are in the intestine, while many are in lungs and airways. When infected, a patient may complain about abdominal pain, diarrhea, coughing and breathlessness.

    Viruses can be spread or transmitted through various ways. Some people may get a viral infection by swallowing or inhaling virus, by being bitten by insects, through sexual contact or through transfusion of contaminated blood.

    How does Viral Infection affect human body?

    There are many kinds of viruses- gastro intestinal viruses and airways viruses, being the most common ones. These viruses mostly cause fatigue and fever. Other viruses cause other local symptoms such as laryngitis, shingles and cold sores.

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    Identification Of The Virus In The Cell Culture

    Viruses are obligate intracellular parasites so we cannot grow them in ordinary media and require living cells for the growth and propagation. The growth of the virus in the cell culture may produce a characteristic cytopathic effect which helps us for presumptive diagnosis. If that particular virus does not produce the cytopathic effect, its presence can be detected by several other techniques such as Immunofluorescence assay , Radioimmunoassay , Hemadsorption, decrease in acid production of infected cells, ELISA, Complement fixation, Hemagglutination inhibition method, neutralization, etc.

    What Is Electron Microscopy

    How to diagnose a hepatitis E infection.

    Electron microscopy involves directing a beam of electrons at a sample producing an image. It can provide much higher resolution images than a standard light microscope. It is rarely used in practice. However it can be useful to identify atypical and rare viral infections in the immunosuppressed patients presenting with unusual skin lesions.

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    Diagnosis And Epidemiological Surveys

    Light microscopy remains the preferred method for diagnosis of herpes-like virus infections in suspect samples. However, this method is poorly suited to diagnosis of viral diseases and should be supported by other techniques such as transmission electron microscopy. Even so, microscopic techniques are time consuming and unsuitable for epidemiological surveys. The lack of bivalve cell lines precludes in vitro culture and the observation of virus cytopathic effects. The purification of OsHV-1 from fresh infected larval C. gigas has served as a platform for the generation of molecular biological reagents for diagnosis. Procedures to detect herpesviruses in oysters using polymerase chain reaction and in situ hybridization have been developed and are suitable for epidemiological surveys of field samples, such as are currently being performed on oyster spat and larvae from commercial hatcheries and shellfish farms in France.

    FRANK FENNER, … DAVID O. WHITE, in, 1987

    Antiviral Treatment For Specific Viruses

    Specific viral causes of throat infections may benefit from treatment with antiviral medications. For example, people with influenza virus may benefit from taking oseltamivir , zanamivir , or peramivir if given within 48 hours of the start of symptoms. People with HSV may benefit from acyclovir if given within three to four days of the start of symptoms. People with HIV should be started on highly active antiretroviral therapy , which includes a combination of medications to treat the HIV.

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    Importance Of Viral Diagnosis

    The Viral diagnosis will be particularly helpful in different clinical situations such as

    • There are important public health considerations. For example influenza and arbovirus encephalitis, etc.
    • There are significant risks to susceptible persons exposed to the patient. For example measles, hepatitis B, and varicella.
    • In a situation that involves Important prognostic considerations. For example congenital infections, encephalitis, and infections in immunocompromised hosts.
    • In a situation where Withdrawal of antibiotics might serve the patients interest. For example respiratory virus infections and viral meningitis such as respiratory virus infections and viral meningitis.
    • In a situation where therapeutic action depends on viral diagnosis. For example treatment with an antiviral agent, hospital infection control, and therapeutic abortion for rubella in pregnancy.
    • Laboratory diagnosis of viral infections will help medical staff to understand about diseases or epidemiology and improve subsequent care of similar patients.

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