Swine Flu

Case Definition

 # A suspected case of swine influenza A(H1N1) virus infection is defined as a person with acute febrile respiratory illness (fever > 38 C) with onset

* Within 7 days of close contact with the person who is confirmed case of swine influenza A(H1N1) virus infection, or

* Within 7 days of travel to community where there are one or more confirmed swine influenza A(H1N1) cases, or * Resides in a community where there are one or more confirmed swine influenza cases.

# A probable case of swine influenza A(H1N1) virus infection is defined as a person with an acute fabrile respiratory illness who

* Is positive for influenza A(H1N1) but unsubtypable for H1 and H3 by influenza RT-PCR or reagents used to detect seasonal influenza virus infection, or * Is positive for influenza A by an influenza rapid test or an influenza immunofluorescence assay (IFA) plus meets criteria for a suspected case, or * Individual with a clinically compatible illness who died of an unexplained acute respiratory-illness who is considered to be epidemiologically linked to a probable or a confirmed case.

# A confirmed case of swine influenza A(H1N1) virus infection is defined as a person with an acute febrile respiratory illness with laboratory confirmed swine influenza A(H1N1) virus infection at WHO approved laboratories by one or more of the following tests -

* Real Time PCR * Viral Culture * Four-Fold rise in swine influenza A (H1N1) virus specific neutralizing antibodies.   Epidemiology # The agent - Genetic sequencing shows a new subtype of influenza A(H1N1) virus with segments from four influenza viruses : North American Swine, North American Avian,Human Influenza and Eurasian Swine.

# Transmission-by droplet infection and fomites. # Incubation period-1-7 days # Communicability-From 1 day before to 7 days after the onset of symptoms. If illness persists for more than 7 days,chances of communicability may persist till resolutin of illness. Children may spread the virus for a longer period. Clinical features

# Important clinical features of swine influenza include fever, and upper respiratory symptoms such as cough and sore throat. Head ache, fatigue, diarrhea and vomitting have also been observed. # Complications are expected to be similar to seasonal influenza: sinusitis, otitismedia, croup (laryngotracheomalacia), pneumonia, bronchiolitis, status asthmaticus, mrocarditis, pericarditis, myositis, rhabdomyolysis, encephalitis, seizures, toxic shock syndrome and secondary bacterial pneumonia with or without sepsis. # Individuals at extremes of age and with preexisting medical conditions are at a higher risk of complications and exascerbation of the underlying conditions.

Investigations   # Clinical specimens- nasopharyngteal swab is the best. Others can be throat swab, nasal swab, nasopharyngeal aspirate and tracheal aspirate (ofr injtubated patients). Paired blood samples at an interval of 14 days for serological testing should also be collected. # Swab specimen to be obtained on swab stick with a synthetic tip (of polyester or dacron) and aluminium or plastic shaft. # Time of collection- Sample should be collected by a trained physician or microbiologist, preferably before administration of an antiviral drug and as soon as the symptoms begin. Keep the specimen at 4 C temp in viral transport media unttil transported for testing within 48 hours. If mopre than 48 hours, store at -70 C. Avoid any freeze thaw cycles. # Transport- The sample should be transported to the designated laboratories within 24 hours. # Various tests for confirmation are- * RT PCR (Real time PCR)- it targets 2 separate regions of hemagglutinin gene of the virus. * Isolation of the virus in culture. * Serology- 4 fold rise in the specific virus neutralising antibodies.

Guidelines for the testing of persons # Any person with flu like symptoms such as fever, cough, sore throat, cold, running nose etc should go to a designated government facility for giving his/her sample for testing the H1N1 virus. After clinical assesment, the designated medical officer would decide on the need for testing. Except for the cases that are severe, the patient would be allowed to go home. # If tested as positive for H1N1 and in case the symptoms are mild, the patient would be informed and given the option of admission into the hospital or isolation and treatment at his own home. # In case the test is negative, the patient will be accordingly informed. # These guidelines would however not apply to passengers who are identified through screening at the points of entry. The existing policy of isolating passengers with flu like symptoms would continue.

Treatment # The guiding principles are: * Early implementation of infection control precautions to minimize nosocomical\household spread of disease * Prompt treatment to prevent severe illness and death. * Early identification and follow up of persons at risk. # Oseltamivir Medication- Oseltamivir (Tamiflu) is the recommended drug both for prophylaxis and treatment.

# Mechanism of action-
Oseltamivir phosphate is an oral prodrug which undergoes hydrolysis by hepatic esterases to form active oseltamivir carboxylate, also referred to as GS4071. Oseltamivir carboxylate acts by selective inhibition of influenza A and B viral neuraminidase. A lipophilic side chain of the active drug binds to the virus enzyme, blocking its ability to cleave sialic acid residues on the surface of the infected cell and resulting in an inability to release progeny virions.

# Resistance-
* Reduced susceptibility to oseltamivir carboxylate is associated with mutations that results in amino acid changes in viral neuraminidase or viral hemagglutinin or both. * Cross-resistance between zanamivir-resistant influenza mutants and oseltamivir-resistant influenza mutants has been observed. # Pharmacokinetics- * In addition to the active ingredient, each capsule contains pregelatinized starch, talc, povidone K 30, croscarmellose sodium, and sodium stearyl fumarate. * Readily absorbed from the gastrointesinal tract and is extensively converted predominantly by hepatic esterases to oseltamivir carboxylate. * Coadminstration with food has no significant effect. * Binding of oseltamivir carboxylate to human plasma protein is low (3%). The binding of oseltamivir to human plasma protein is 42% which is insufficient to cause significant displacement-based drug interactions. * Eliminate by conversion to oseltamivir carboxylate, which is not further metabolized and is eliminated in the urine. # Adverse reactions: Oseltamivir is genrally well tolerated, gastrointestinal side effects (transient nausea, vomiting) may increase with increasing doses, particularly above 300mg/day. Occasionally it may cause bronchitis, insomnia and vertigo. Less commonly angina, pseudo membranous colitis and peritonsillar abscess have also been reported. There have been rare reports of anaphylaxis and skin rashes. In children, most frequent reported side effect is vomiting. Infrequently, abdominal pain, epistaxis, bronchitis, otitis media, dermatits and conjunctivitis have also been observed. There is no recommendation for dose reduction in patients with heptic disease. Though rare reporting of fatal neuro-psychiatiric illness in children and adolescents have been linked to oseltamivir, there is no scientific evidence for a causal relationship.

# It is contraindicated in people will known allergy to any of the components.

# Supportive therapy includes * IV Fluids * Parentral nutrition * oxygen therapy/ ventilatory support * Antibiotics for secondary infection * Vasopressors for shock * Paracetamol or ibuprofen is prescribed for fever, myalgia and headache.
* Patients is advised to drink plenty of fluids.
* Smokers should avoid smoking.
* For sore throat, short course of topical decongestants, saline nasal drops, throat lozenges and steam inhalation may be benefecial. * Salicylate / aspirin is strictly contra-indicated in any influenza patient due to its potential to cause Reye's syndrome.
* The suspected case would be costantly monitored for clinical / radiological evidence of lower respiratory tract infection and for hypoxia (respiratory rate, oxygen saturation, level of consciousness).
* Patients with sign of tachypnea, dyspnea, respiratory distress and oxygen saturation less than 90 percent should be supplemented with oxygen therapy. Types of oxygen devices depend on the severity of hypoxic conditionswhich can be started from oxygen cannula, simple mask, partial re-breathing mask (mask with reservoir bag) and non re-breathing mask. In children, oxygen hood or head boxes can be used. * Maintain airway, breathing and circulation (ABC).
* Maintain hydration, electrolyte balance and nutrition.
* If the laboratory reports are negative, the patient would be discharged after been given full cource of oseltavimir. Even if the test results as negative, all cases with strong epidemiological criteria need to be followed up.
* Immunomodulating drugs has not been found to be beneficial in treatment of ARDS or sepsis associated multi organ failure. High dose corticosteroids in particular have no evidence of benefit and there is potntial for harm. Low dose corticosteroids (Hydrocotisome 200-400 mg/day) may be useful in presisting septic shock (SBP * Suspected case not having pneumonia do not require antibiotic therapy. Antibacterial agents should be administered, if required, as per locally accepted clinical practice guidelines. Patients on mechanical ventilation should be administered antibiotics prophylactically to prevent hospital association infections.

# Discharge Policy
* Adult patients should be discharged 7 days after symptoms have subsided.
* Children should be discharged 14 days after symptoms have subsided.
* The family of patients discharged earlier should be educated on personal hygiene and infection control measures at home; children should not attend school during this period.   Prophylaxis  
# Chemo Prophylaxis- should be given for    * All close contacts of suspected, probable and confirmed cases. Close contacts include household / social contacts, family members, workplace or school contacts, fellow travelers etc.
* All health care personnel coming in contact with suspected, probable or confirmed cases. * Oseltamivir is the drug of choice.
* Prophylaxis should be provided till 10 days after last exposure ( maximum period of 6 weeks)

# Vaccination-
* Inactivated vaccine is used.
* Target groups include pregnant women, people who live with or care for children younger than 6 months of age, healthcare and emergency medical services personnel, elderly.

# Non-Pharmaceutical Interventions- Close Contacts of suspected, probable and confirmed cases should be advised to remain at home (voluntary home quarantine) for at least 7 days after the last contact with the case. Monitoring of fever should be done for at least 7 days. 
# Decontaminating contaminated surfaces, fomites and equipments- * Cleaning followed by disinfection should be done for contaminated surfaces and equipments.
* Use phenolic disinfectants, quaternary ammonia compounds, alcohol or sodium hypochlorite. Patients rooms/areas should be cleaned at least daily and terminally after discharge. In addition to daily cleaning of floors and other horizontal surfaces, special attention should be given to cleaning and disinfecting frequently touched surfaces.
* To avoid possible aerosolization of H1N1 virus, damp sweeping should be performed.
* Clean heavily soiled equipment and then apply a disinfectant effective against influenza virus before removing it from the isolation roon/area.
* When transporting contaminated patient-care equipment outside the isolation room/area, use gloves followed by hands hygiene. Use standard prcautions and follow current recommendations for cleaning and disinfection or sterilization of reusable patient-care equipment.
# Guidelines for waste disposal- * All the waste has to be treated as infectious waste and decontaminated as per standard procedures.
* Articles like swabs/gauges etc are to be discarded in the yellow coloured autocalavable biosafety bags after use, the bags are to be autocalaved followed by incineration of the contents of the bag.
* Waste like used gloves, face masks and disposable syringes etc are to be discarded in Blue/White autoclavable biosafety bags which should be autocalaved/microwaved before disposal.
* All hospitals and laboratory personnel should follow the standard guidelines (Biomedical waste and handling rules, 1998) for waste management.