Swine influenza virus refers to influenza cases that are caused by Orthomyxovirus endemic to pig populations. SIV strains isolated to date have been classified either as Influenza(virus C or one of the various subtypes of the genus Influenza virus A)
Swine Influenza (Flu)
Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza that regularly cause outbreaks of influenza among pigs. Swine flu viruses do not normally infect humans, however, human infections with swine flu do occur, and cases of human-to-human spread of swine flu viruses has been documented.
EPIDEMIOLOGY The disease is considered endemic in the United States. Outbreaks are also known to have occurred in North and South America, Europe, Africa (Kenya), Mexico and in parts of Asia. Notable outbreaks:- 1918 - pandemic in humans 1976 - U.S. outbreak 1988 zoonosis – there was no community outbreak 1998 - US outbreak in swine 2007 - Philippine outbreak in swine 2009 - outbreak in humans
He says ice-cream made him feel better, and Thank God has now recovered full health. But the rest of the planet has a quick –paced pandemic marching on…. 'Patient Zero' in Swine Flu Outbreak Identified as 5-Year-Old Mexican Boy: Edgar Hernandez
In India till today, 10233 cases have been reported of which 359 have died. Maximum cases have been reported from Pune(Maharashtra), Delhi, Karnataka & Tamilnadu. The first fatality was a 14 year old girl from Pune. She had come in contact with 40 students who travelled from NASA in the US to Pune and though she had not travelled hereself, she got the infection from them. Pune girl Rida Sekh
In U.P. till now 328 cases of Swine flu has been confirmed in Lucknow out of which 2 had died. Two confirmed cases of swine flu reported from jhansi till date. 2
Swine Flu and Virus
Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza virus that regularly causes outbreaks of influenza in pigs. Swine flu viruses cause high levels of illness and low death rates in pigs. Swine influenza viruses may circulate among swine throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans. The classical swine flu virus (an influenza type A H1N1 virus) was first isolated from a pig in 1930.
THE VIRUS The 2009 swine flu outbreak in humans is due to an apparently virulent new strain of influenza A virus subtype H1N1, produced by reassortment from one strain of human influenza virus, one strain of avian influenza virus and two separate strains of swine influenza. This virus was originally referred to as swine flu but the WHO decided to rename it as Influenza A H1N1 virus on 30 th April 2009 in order to avoid confusion over the danger posed by pigs, especially pork consumption, by which the disease is not known to occur. This was also to avoid unnecessary slaughter of pigs.
Cause by Reassortment of different strains
Like all influenza viruses, swine flu viruses change constantly. Pigs can be infected by avian influenza and human influenza viruses as well as swine influenza viruses. When influenza viruses from different species infect pigs, the viruses can reassort (i.e. swap genes) and new viruses that are a mix of swine, human and/or avian influenza viruses can emerge
Swine Flu differs from Human Flu
The H1N1 swine flu viruses are antigenically very different from human H1N1 viruses and, therefore, vaccines for human seasonal flu would not provide protection from H1N1 swine flu viruses
Electron microscope image of the reassorted H1N1 virus. The viruses are 80-120 nanometers in diameter.
Present Swine Flu strains
At this time, there are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H1N1 viruses.
Out breaks among Pigs
Outbreaks among pigs normally occur in colder weather months (late fall and winter) and sometimes with the introduction of new pigs into susceptible herds. Studies have shown that the swine flu H1N1 is common throughout pig populations worldwide, with 25 percent of animals showing antibody evidence of infection.
Pigs can harbour influenza viruses can be adapted to Humans www.medicalppt.blogspot.com FOR MORE LECTURES
How man is exposed
Most commonly, these cases occur in persons with direct exposure to pigs (e.g. children near pigs at a fair or workers in the swine industry). In addition, there have been documented cases of one person spreading swine flu to others.
Human to Human Tranmission – Limited to close contacts and closed groups of people. If a swine virus established efficient human to human transmission, it can cause an influenza pandemic. The impact of a pandemic caused by such a virus is difficult to predict: It depends on- virulence of the virus, existing immunity among people, cross protection by antibodies acquired from seasonal influenza infection host factor Swine influenza viruses can give rise to a hybrid virus by mixing with a human influenza virus and can cause pandemic.
How Swine Flu presents in Humans
The symptoms of swine flu in people are expected to be similar to the symptoms of regular human seasonal influenza and include fever, lethargy, lack of appetite and coughing. Some people with swine flu also have reported runny nose, sore throat, nausea, vomiting and diarrhea
Primary viral pneumonia
Secondary bacterial pneumonia
Exacerbation of COPD and bronchial asthma
COMPLICATINS OF H1N1 FLU
H1N1 INFLUNZA AND AIDS
Any influenza carries potential risks for persons with HIV infection. It is known that adults and adolescents with HIV infection, especially persons with low CD4 cell counts, are at higher risk for viral and bacterial lower respiratory tract infections and for recurrent pneumonias. Because adults and adolescents infected with HIV experience more severe complications of seasonal influenza, it is reasonable to assume that they are also at higher risk for swine influenza complications.
Several studies have reported higher hospitalization rates, prolonged illness and increased mortality, especially among persons with AIDS. Thus, immune compromised persons, including HIV-infected adults and adolescents and especially persons with low CD4 cell counts or AIDS can experience more severe complications of seasonal influenza and it is possible that HIV-infected adults and adolescents are also at higher risk for swine-origin influenza complications .
HIV-infected adults and adolescents with swine-origin influenza would be expected to present with typical acute respiratory illness (e.g., cough, sore throat, rhinorrhea) and fever or feverishness, headache, and muscle aches. For some HIV-infected persons, especially persons with low CD4 cell counts, illness might progress rapidly, and might be complicated by secondary bacterial infections including pneumonia. HIV-infected persons who have suspected swine-origin influenza A (H1N1) virus infection should be tested.
Adults and adolescents with HIV infection, especially persons with low CD4 cell counts, are known to be at higher risk for viral and bacterial lower respiratory tract infections and for recurrent pneumonias. Evidence that influenza can be more severe for HIV-infected adults and adolescents comes from studies among HIV-infected persons who had seasonal influenza; these data are limited.
Persons with HIV infection should remain vigilant for the signs and symptoms of influenza . Persons with HIV infection who are concerned that they might be experiencing signs or symptoms of influenza infection, or who are concerned they might have been exposed to a confirmed, probable or suspected case of influenza infection, either seasonal influenza or swine-origin influenza A (H1N1), should consult their healthcare provider to assess the need for evaluation and for possible anti-influenza treatment prophylaxis.
How long can an infected person spread swine flu to others?
People with swine influenza virus infection should be considered potentially contagious as long as they are symptomatic and possible for up to 7 days following illness onset. Children, especially younger children, might potentially be contagious for longer periods.
Is the eating Pork infects ?
No. Swine influenza viruses are not transmitted by food. You can not get swine influenza from eating pork or pork products. Eating properly handled and cooked pork and pork products is safe. Cooking pork to an internal temperature of 160°F kills the swine flu virus as it does other bacteria and viruses
DIAGNOSIS During the 2009 swine flu outbreak in the United States, CDC advised physicians to consider swine influenza infection in the differential diagnosis of patients with acute febrile respiratory illness who have either been in contact with persons with confirmed swine flu, or who were in one of the five U.S. states that have reported swine flue cases or in Mexico during the 7 days preceding their illness onset. A diagnosis of confirmed swine flu requires laboratory testing of a respiratory sample (a simple nose and throat swab)
LABORATORY STUDIES CBC Leukopenia and relative lymphopenia Thrombocytopenia may be present Real time PCR (RTPCR) Viral culture Four-fold rise in swine influenza A(H1N1) virus-specific neutralizing antibodies
There are 19 labs all over our country to test for Swine flu. We have only 5000 kits for testing but attempts are being done to procure more kits.
PREVENTION Prevention in swine- Facility Management Using disinfectants Ambient temperature to control virus in the environment. The virus is unlikely to survive outside living cells for > 2 wks except in cold (above freezing) conditions.
Clean your hands
Washing your hands often will help protect you from germs.
Hand washing proved to be best procedure in prevention of Majority of Communicable diseases.
Avoid close contact
Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
Aerosols spread the virus in any environment
Cover your mouth and nose.
Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick
Avoid touching your eyes, nose or mouth
Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth.
Stay home when you are sick.
If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness .
Practice other good health habits
Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious.
Unnecessary Migration of people from epidemic and endemic areas to be reduced.
Simple measures carry get good Benefits
Cover your mouth and nose. Use a tissue when you cough or sneeze and drop it in the trash. If you don’t have a tissue, cover your mouth and nose as best you can.
Clean Hands saves you
Clean your hands often. Clean your hands every time you cough or sneeze. Hand washing stops germs. Alcohol-based gels and wipes also work well.
Healthy Habits reduces the Attacks www.medicalppt.blogspot.com FOR MORE LECTURES
* Household close contacts (of confirmed, probable, or suspected case) at high-risk for complications of influenza + chronic medical conditions + aged ≥ 65 years + aged ≤ 5 years + pregnant women * School children or children in daycare at high-risk for complications of influenza (certain chronic medical conditions) who had close contact (face-to-face) with confirmed, probable, or suspected case Indications for antiviral chemoprophylaxis
* Any healthcare worker at high-risk for complications of influenza (persons with certain chronic medical conditions, elderly) working in area with confirmed swine influenza A (H1N1) cases, or who is caring for patients with any acute febrile respiratory illness Indications for antiviral chemoprophylaxis
treat during exposure period and for 10 days after last known exposure to ill confirmed case of swine influenza A (H1N1) virus infection
treat for 10 days after last known exposure to ill confirmed case of swine influenza A (H1N1) virus infection
10 mg (2 inhalations) once daily for adults and children ≥ 5 years old
adults and children ≥ 13 years old - 75 mg once daily
children aged 1-12 years - dose based on weight
≤ 15 kg 30 mg once daily
15-23 kg 45 mg once daily
23-40 kg 60 mg once daily
> 40 kg 75 mg once daily
Dosing of Antivirals
TREATMENT GUIDANCE NOTE The majority of influenza cases may be cared for at home with the simple supportive care. However, if they develop dangers signs then patients may need to access a health-care facility. These danger signs may include: weakness/not able to stand inability to drink lethargy dehydration and unconsciousness high fever convulsions very difficult/obstructed breathing or shortness of breath
In the case of mild illness, patients should be provided with supportive care at home by a designated caregiver. Supportive care entails- Bed rest Fluids Medication for fever Antibiotics if prescribed Good nutrition
Inpatient treatment should include: Treatment of dehydration with IV or oral rehydration fluids; Supplemental oxygen therapy by face mask rather than nasal prongs; Antibiotics (oral or parenteral) for secondary bacterial infections; Non-aspirin antipyretics for pain and fever Nutritional supplementation as needed. In HIV infected individuals, a distinction between opportunistic pneumonia and secondary pneumonia from pandemic influenza may be difficult.
Drugs which are effective in Swine Flu
There are four different antiviral drugs that are licensed for use in the US for the treatment of influenza: Amantidine, rimantadine, oseltamivir and zanamivir . While most swine influenza viruses have been susceptible to all four drugs.
Oseltamivir is generally available by prescription only.
The usual adult dosage for treatment of influenza is 75 mg twice daily for 5 days, beginning within 2 days of the appearance of symptoms and with decreased doses for children and patients with renal impairme nt.
Drugs proved resistant at Present
Most recent swine influenza viruses isolated from humans are resistant to Amantidine and Rimantadine
Treatment in HIV Patients
Recommendations for use of influenza antivirals for HIV-infected adults and adolescents might change as additional data on the benefits and risks of antiviral therapy in such persons become available. No adverse effects have been reported among HIV-infected adults and adolescents who received oseltamivir or zanamivir. There are no known absolute contraindications for co-administration of oseltamivir or zanamivir with currently available antiretroviral medications.
In health-care settings, a system of triage Patient separation Prioritization of use of antiviral medicines and Personal protective equipment (PPE) which include high efficiency masks ideally (N95 mask or else triple layer surgical mask) gowns, goggle, gloves, caps and shoe covers. According to risk of exposure, and patient management should be in place to focus efforts on the most effective interventions to reduce mortality and any further morbidity. DISCHARGE POLICY Adult patients should be discharged 7 days after symptoms have subsided, where as children should be discharged 14 days after symptoms have subsided.
Protection of staff: Standard Precautions – Basic measures to minimize direct unprotected exposure to blood and body fluids. Droplet Precautions – Medical masks when close to patients with respiratory symptoms. Patients and caregivers should be trained to wear and dispose off masks during the infectious period of the patient. The mask need not be worn all day and only when close contact (within approximately 1m) with the caregiver or others is anticipated. Mask should be disposed off safely if wet with secretions.
Self-monitoring – Health staff should monitor their temperatures twice daily. Fevers should be reported. If a staff member becomes unwell, treatment with antiviral as well as supportive care as for other patients should be provided at home by a caregiver.
A single-dose H1N1 swine flu vaccine may soon happen. Contrary to what was earlier expected, the vaccine against H1N1 may not be multi-dose, as results from a pilot study of Novartis H1N1 candidate vaccine revealed a strong immune response after just one shot. The vaccine might be used in trials in India as well.
Scientists from the University of Leicester, who tested the vaccine on 100 healthy volunteers aged between 18 and 50, found that more than 80% of the volunteers showed a strong, potentially protective immune response after one dose, with more than 90% showing the same response after two doses.
Single-dose swine flu vaccine in the works
The general public must be educated about the signs symptoms and spread of Swine flu. This can be done by television, radio, newspaper etc. PUBLIC AWARENESS
Government of India is taking steps to control this pandemic. There are plans to stockpile 15 billion oseltamivir pills. Steps are also being taken to prevent the spread of the disease.
Government should ensure proper screening of passengers at all international airports, isolating the positive cases and wearing personal protective equipments are the mainstay of prevention.