Novel Influnza A H1N1 virus Infection

Swine Flu Background

• Contageous respiratory disease with mild to severe symptoms.

• Human to human transmission like seasonal influenza via sneezing coughing, etc.

• The first outbreak in 1918 called “Spanish influenza pandemic affecting 1/3 of world population (500 million) with 50 million deaths.

Swine Flu Background• Second outbreak in 1976 in New Jersey• Vaccination halted after 40 million vaccination

due to appearance of Guillain-Barre Syndrome and 25 deaths.

• Increased flu risk in pregnant women, particularly during the second and third trimesters.

• Increased risk of fetal death or spontaneous abortions in infected pregnant women.

Novel H1N1 flu infection• From April 15, 2009 to July 24, 2009, it is estimated that

more than one million people became ill with novel H1N1 flu in the United States.

• From April 15, 2009 to July 24, 2009, a total of 43,771 confirmed and probable cases of novel influenza A (H1N1) infection were reported.

• Of these cases reported, 5,011 people were hospitalized and 302 people died.

• In India 782 cases reported 511 cured 4 deaths.

Novel H1N1 flu Global Map

   confirmed death and infections   confirmed infections   unconfirmed infections

Swine Flu Features• Duration 4 – 6 days.• Infectious period – 1 day prior to onset of symptoms

to 7 days after onset.• Suspect in pt who present with febrile respiratory

illness• Onset within 7 days of close contact with confirmed

infection.• Onset within 7 days of travel to areas where

sustained human transmission exists• Acute illness in person who resides in community

where atleast 1 confirmed case.

Symptoms and Complications• Symptoms of swine flu are similar to influenza infections.• Strong immune response may cause some collateral tissue

damage. • Majority (about 90%-95%) of people feel terrible but recover

with no problems.• Some patients develop severe respiratory symptoms and

need respiratory support.• Patients may get pneumonia (bacterial secondary infection) if

the viral infection persists, and some develop seizure.• Death often occurs from secondary bacterial infection of the

lungs; appropriate antibiotics need to be used in these patients. Mortality Rate – 1% - 6%

Novel Influenza A H1N1 virus

• Novel H1N1 virus is also called “swine flu” because many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine).

• It has two genes from flu viruses that normally circulate in pigs, bird (avian) genes and human genes.

• Scientists call this a "quadruple reassortant" virus.

Symptoms in hospitalized novel H1N1 flu patients

Symptom Number (%)

Fever* 249 (93%)

Cough 223 (83%)

Shortness of breath 145 (54%)

Fatigue/Weakness 108 (40%)

Chills 99 (37%)

Myalgias 96 (36%)

Rhinorrhea 96 (36%)

Sore Throat 84 (31%)

Headache 83 (31%)

Vomiting 78 (29%)

Wheezing 64 (24%)

Diarrhea 64 (24%)

Signs of Emergency

• Novel H1N1 swine flu can progress rapidly.– Shortness of breath, either during physical activity or while resting,

difficulty in breathing, turning blue, bloody or colored (not clear) sputum, chest pain.

– Altered mental status.– High fever that persists beyond three days.– Low blood pressure.– In children, danger signs include fast or difficult breathing,.

Emergency in Children

• In children, emergency warning signs are:– Fast breathing or trouble breathing – Bluish or gray skin color – Not drinking enough fluids – Severe or persistent vomiting– Not waking up or difficulty in waking up, not interacting ,

lack of alertness, little or no desire to play.– Being so irritable that the child does not want to be held – Flu-like symptoms improve but then return with fever

and worse cough

Emergency in Adults

• In adults, emergency warning signs are: – Difficulty breathing or shortness of breath – Pain or pressure in the chest or abdomen – Sudden dizziness – Confusion – Severe or persistent vomiting – Flu-like symptoms improve but then return with

fever and worse cough

Care for Swine Flu

• Sick patient• Bed rest, increased fluid consumption, cough

supressants, analgesic antipyretics, avoid close contact, wash hands after contact, avoid touching eyes, nose and mouth.

• Self isolate in home for 7 days or more if flu like symptom.

• Wear face mask, if going out.• Seek medical help if breathing difficulty or severe

illness.

Care for Swine Flu

• Household not sick• Remain at home at the earliest signs of

sicknes.• Minimize contact with community• Designate single family member as care taker.• Wash hands with soap and water frequently.• Do not use utensils and linen used by patient,

without washing.

Novel H1N1 flu infection• Estimated community rate of influenza-like-illness approximately 6% - 6.9% of the

population.

• Causes greater disease burden on people younger than 25 years of age than older people .

• Greater risk of serious flu-related complications in pts of asthma, diabetes, heart disease, kidney disease, suppressed immune system, neurocognitive, neuromuscular disorder, obesity, age group <5 and >65 yr and pregnancy.

• The generation time – acute respiratory illness (ARI) - 2.0-3.1 days – influenza like illness (ILI) - 2.4-3.1 days .

• A secondary attack rate in household contacts– For acute-respiratory-illness (ARI) - 18 % to 19% – For influenza-like-illness (ILI) - 8% to 12%.

Preventive Care• People infected with novel H1N1 flu shed virus may be able

to infect others from 1 day before getting sick to 5 to 7 days after.– Cover nose and mouth with a tissue when you cough or sneeze.– Wash hands often with soap and water, especially after you

cough or sneeze.– Avoid touching eyes, nose or mouth.– Try to avoid close contact with sick people.– If sick with flu-like illness, stay home for at least 24 hours after

your fever is gone.– Healthy person with an ill family member at home can go to

work as usual with daily health monitoring and precautions.

Novel H1N1 flu infection

Case Rate Hospitalization Rate

Mortality in 268 Hospitalized Patients

Contamination & Cleaning

• Virus can survive on surfaces and can infect a person for 2 to 8 hours after being deposited on the surface.

• Virus is destroyed by heat (167-212°F [75-100°C, chlorine, hydrogen peroxide, detergents (soap), iodophors (iodine-based antiseptics), and alcohols.

• Virus spread when a person touches something that is contaminated and then touches his or her eyes, nose, or mouth.

Contamination & Cleaning

• Novel H1N1 viruses are not spread by food. • Tap water that has been treated by

conventional disinfection processes does not spread the virus.

• Chlorine treated water in swimming pool water parks does not spread the virus but recreational water venues can.

Contamination & Cleaning

• To prevent the spread of influenza virus – keep surfaces (especially bedside tables, surfaces

in the bathroom, kitchen counters and toys for children) clean with a household disinfectant.

– Linens, eating utensils, and dishes should not be shared without washing thoroughly with soap and water first.

– Wear face mask when moving in public places

Recommended treatment and Prophylaxis

• Treatment • Same as those recommended for seasonal influenza• Oseltamivir, zanamivir ( amantadine, rimantadine) for 5 days.• Start drug treatment within 48 hours of onset of symptoms.

• Chemoprophylaxis– Oseltamivir, zanamivir for 7 days after the last known exposure to an ill

confirmed case.– Household close contacts who are at high-risk for complications.– School children who had close contact (face-to-face) with a confirmed or

suspected case. – Travel to infection areas if at high-risk for complications.– Health care workers or public health workers who had unprotected close

contact with an ill confirmed case.

Preventive measures in School• Stay home when sick for at least7 days or for 24 hours after no fever, or

signs of fever.• Students who have an ill household member should stay home for five

days from the day the first household member got sick.• Separate ill students and staff and wear face mask.• Cover nose and mouth when coughing or sneezing.• Wash hands frequently with soap and water.• Frequent cleaning of areas that students and staff touch in routine

manner.• Check students and staff for fever and other symptoms of flu daily.• Early treatment of high-risk students and staff.• Consideration of selective school closure.