Swine flu influenza virus

The airways contain a copious mucopurulent exudate, and the bronchial and mediastinal lymph nodes are edematous but rarely congested. There may be severe pulmonary edema, especially of interlobular septae, or a serous or serofibrinous pleuritis. Histologically, the lesions, when fully developed, are primarily those of an exudative bronchiolitis with some interstitial pneumonia. Virus can be isolated from nasal and oral secretions in the febrile phase, from affected lung tissue in the early acute stage, or from udder wipes collected from sows with infected suckling piglets.

Sequencing and characterization of the influenza viral isolates may be needed to select epidemiologically relevant strains that may be needed for evaluating virus-specific antibodies or custom vaccine production.

A clinical diagnosis presumptive diagnosis can be made by observing the sudden onset of a large number of pigs showing coughing, fever, and nasal secretions. However, subclinical and chronic influenza infections are common, and in those cases, cough and nasal secretions may be sporadic.

A retrospective diagnosis can be made by demonstrating a rise in virus-specific antibody titers in acute and convalescent serum samples using the hemagglutination inhibition test. Both H3 and H1 subtype antigens should be included. This test is also used for herd surveys, and an ELISA against the nucleoprotein not subtype specific is also available.

To diagnose uncomplicated influenza infection, conditions such as pasteurellosis Pasteurellosis in Pigs Pasteurellosis is most commonly seen in pigs as a complication of mycoplasmal pneumonia, although swine influenza, Aujeszky disease, Bordetella bronchiseptica, or Haemophilus parahaemolyticus Swine are the primary host, but other species are also occasionally infected. Clinical signs include reproductive Supportive care including antipyretics and antimicrobials to treat secondary bacterial infections.

There is no effective treatment , although antimicrobials may reduce secondary bacterial infections and antipyretics may provide symptomatic relief. Expectorants also may help relieve signs in severely affected herds. Vaccination and strict import controls are the only specific preventive measures. Sow vaccination either prefarrowing or the entire herd at once mass vaccination are the most common vaccination protocols.

Sow vaccination attempts to maximize the transfer of maternal immunity to the progeny. Piglet vaccination is possible, reduced efficacy due to maternal antibodies is an issue. Commercially available killed vaccines that contain both H1N2 and H3N2 subtypes appear to induce a strong protective immune response. In North America, custom-made autogenous vaccines prepared with the farm isolate s are common, and in a live-attenuated influenza vaccine became commercially available.

Lastly, seasonal vaccination of personnel interacting with pigs is recommended to limit the bidirectional transmission of IAV between pigs and people. Detection of influenza virus in tissues, nasal secretions, and oral fluids by RT-PCR is the most common and rapid diagnostic method to detect influenza virus.

Diseases of Swine, 11th Edition. Wiley-Blackwell; These changes are characteristic of the fibroproliferative stage of acute respiratory distress syndrome and diffuse alveolar destruction. Bacterial coinfections were also identified in some autopsy cases.

The most common bacteria isolated included Streptococcus pneumoniae , Stre ptococcus pyogenes , Staphylococcus aureus , community-acquired, methicillin-resistant Staphy lococcus aureus, and Haemophilus influenzae.

The history and clinical presentations of H1N1 swine influenza have ranged from mild flu symptoms to severe respiratory symptoms and possibly death depending on the age of the patient, co-morbidities, vaccination status, and natural immunity in patients to the virus.

According to the CDC, the signs and symptoms in humans infected with the H1N1 swine flu were similar to those of influenza. These include a fever and chills, cough, sore throat, congested eyes, myalgia, shortness of breath, weight loss, chills, sneezing, headache, rhinorrhea, coughing, dizziness, abdominal pain, decreased appetite, and fatigue. The H1N1 strain also showed an increased number of people reporting vomiting and diarrhea as well.

Because most of these symptoms are not exclusive to swine flu, a detailed history must also be taken to take into account the differential diagnosis of swine flu if the patient has directly contacted someone with confirmed swine flu or has been in an area that had documented cases of swine flu.

Respiratory failure was the most common cause of death in severe cases. Other causes included high fever causing neurological problems , pneumonia causing sepsis , dehydration and severe hypotension from vomiting and diarrhea , electrolyte imbalance associated complications, and kidney failure. More severe cases and fatalities were more likely observed in children younger than 5 years of age and elderly patients older than 60 years. Other risk factors for severe disease include lung disorders such as chronic obstructive pulmonary disease COPD , bronchial asthma, pneumonia, currently pregnant women, obesity, patients undergoing immunosuppressive therapy due to cancer or autoimmune disease, and underlying medical issues such as diabetes.

Pregnant women acquired the infection during their third trimester were at greater risk for complications. Influenza A H1N1 virus infection could be encountered in a wide range of clinical settings and may result in variable pathologic findings.

H1N1 should be one of the differential diagnosis in patients who present with unexplained flu-like symptoms or acute pneumonia in an area with known swine flu cases.

Routine investigations should be performed for the patient who presents with these symptoms. These usually include hematological, microbiological, biochemical and radiologic tests. A respiratory sample simple nose or throat swab is required for a confirmed diagnosis of swine flu.

In humans, these tests include the Reverse transcriptase-polymerase chain reaction test RT-PCR , virus isolation test, and assays to detect a 4-fold increase in influenza virus antigens. The routine tests done to detect human influenza viruses, including the rapid test kits, do not always detect zoonotic viruses. An indication that a novel, possibly zoonotic swine influenza virus could be present, is a detection of the influenza A virus, but not of the hemagglutinins in the seasonal human influenza viruses.

The zoonotic influenza virus infections can sometimes be diagnosed retrospectively by serology, but potential cross-reactivity with human influenza viruses can complicate this diagnosis. Another concern is that the neuraminidase NA and hemagglutinin HA of some swine influenza viruses the main target of the antibodies originated from human influenza viruses, to which people could have already been exposed. State, regional, and national public health laboratories do generally test for the novel influenza viruses.

The initial and best step in management should be to prevent swine flu. Specifically, with the prevention of swine flu in swine, prevention of transmission of swine flu from swine-to-humans, and prevention of human-to-human spread. The best-known prevention method against swine flu is getting the H1N1 swine flu vaccine. In September , the FDA permitted the new swine flu vaccine, and various studies by the National Institute of Health NIH showed that a single dose was enough to create sufficient antibodies to protect against the virus within 10 days.

The vaccination is contraindicated in people who had a previous severe allergic reaction to the influenza vaccination. Those who are moderate to severely ill, including those with or without a fever, should take the vaccination when they recover or are asymptomatic. The management for infected patients depends on the severity of symptoms of influenza, mild to moderate influenza can be treated at home with rest, oral hydration and symptomatic treatment with antipyretics like paracetamol, antihistaminic for nasal congestion and rhinitis and NSAIDS or Paracetamol for headaches and body aches.

Patients with progressive or severe symptoms should be admitted to hospitals and preferably in intensive care units ICU if there are signs suggestive of impending respiratory failure or sepsis or multiorgan dysfunction.

Aggressive supportive measures like intravenous IV hydration, correction of electrolyte imbalances, antibiotics for concomitant bacterial infections. Patients developing acute respiratory distress syndrome ARDS secondary to influenza should be treated with noninvasive or invasive mechanical ventilation. The antiviral medications: zanamivir, oseltamivir, and peramivir have been documented to help reduce, or possibly prevent, the effects of swine flu if the medication is taken within 48 hours of the onset of symptoms.

Known side effects of oseltamivir comprise skin conditions that are occasionally severe and sporadic transient neuropsychiatric events. These possible side effects are the reason the use of oseltamivir is cautioned in the elderly and individuals that have a higher risk of developing these side effects.

An allergy to eggs is the only contraindication to zanamivir. Beginning October 1, , the CDC tested seasonal influenza A H1N1 collected viruses for resistance to the drugs oseltamivir and zanamivir.

It concluded that Pregnant women who contract the H1N1, are at a greater risk of complications because of the body's hormonal changes, physical changes and changes to their immune system to accommodate the growing fetus. For these reasons, the CDC recommends that all pregnant women get vaccinated to prevent the swine influenza virus.

Swine influenza in pregnant women can be treated using antiviral medications: oseltamivir and zanamivir neuraminidase inhibitors. It has been demonstrated that these 2 drugs are most effective when taken within 2 days of becoming sick. Evaluation of data reveals that some patients admitted with swine flu are at risk for sepsis, ARDS and death. Predictors of death include chronic lung disease, obesity, underlying neurological diseases, delayed admission, and other co-morbidity.

Swine flu is very contagious and is easily spread from humans after contact with pigs. The infection rapidly leads to moderate to severe symptoms and deaths are not rare. The key is to prevent the infection in the first place. For best results, an interprofessional team should provide for the evaluation and care of patients with Swine flu. The team should be aware of patients at a high risk of becoming seriously ill if infected including you children, the elderly, those immunocompromized, gestating females, and those suffering from chronic debilitating diseases.

How common is swine flu among pigs? Is there a vaccine for swine flu? Get Email Updates. To receive email updates about this page, enter your email address: Email Address. What's this? Links with this icon indicate that you are leaving the CDC website.

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Cancel Continue. During the flu season, H1N1 caused the respiratory infection in humans that was commonly referred to as swine flu. In August , WHO declared the pandemic over. After the pandemic was over, the H1N1 flu virus became one of the strains that cause seasonal flu.

The flu vaccine can now help protect against the H1N1 flu swine flu. The H1N1 flu virus strain is included in the seasonal flu vaccine, including the vaccine for The signs and symptoms of flu caused by the H1N1 virus are similar to those of infections caused by other flu strains and can include:.

It's not necessary to see a doctor if you're generally healthy and develop flu signs and symptoms, such as fever, cough and body aches. Call your doctor, however, if you have flu symptoms and you're pregnant or you have a chronic disease, such as asthma, emphysema, diabetes or a heart condition, because you have a higher risk of flu complications.

If you have emergency signs and symptoms of the flu, get medical care right away. For adults, emergency signs and symptoms can include:. Influenza viruses such as H1N1 infect the cells that line your nose, throat and lungs. The virus enters your body when you inhale contaminated droplets or transfer live virus from a contaminated surface to your eyes, nose or mouth. If you live in or travel to an area where many people are infected with the H1N1 virus, you may be exposed to the virus.

Each year's seasonal flu vaccine protects against the three or four influenza viruses that are expected to be the most common during that year's flu season. The flu vaccine can reduce your risk of the flu and its severity and lower the risk of having serious illness from the flu and needing to stay in the hospital. Flu vaccination is especially important in the flu season because the flu and coronavirus disease COVID cause similar symptoms. Preventing the flu and reducing the severity of flu illness and hospitalizations could also lessen the number of people needing to stay in the hospital.

The flu vaccine is available as an injection and as a nasal spray. The nasal spray is approved for use in healthy people ages 2 through 49 years old.