Swine Flu In US and Mexico


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Review of the Current Swine Flu in North America and Mexico

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Swine Flu In US and Mexico

  1. 1. 4/25/2009 Mark IV Medical Communications, India. ( www.markivmedical.com) Swine Flu Epidemic in North America Swine influenza is a respiratory disease of pigs caused by type A influenza viruses. Sometimes it may spread to Humans and cause flu-like symptoms. The virus is influenza A virus, carrying the designation H1N1. It is a hybrid reassorted virus and contains DNA typical to avian, swine and human viruses, including elements from European and Asian swine viruses. It clasically causes outbreaks from Mid March to mid May and commonly causes fever, headache, fatigue and cough. As yet, none of the Eight Swine flu cases diagnosed in US has proved fatal, though sources report about 80 fatal cases in Mexico in the past few weeks. Current situation- In the past, CDC received reports of approximately one human swine influenza virus infection every one to two years in the U.S., but from December 2005 through February 2009, a total of 12 human infections with swine influenza were reported from 10 states in the United States. Since March 2009, a number of confirmed human cases of a new strain of swine influenza A (H1N1) virus infection in California, Texas, and Mexico have been identified. 1
  2. 2. 4/25/2009 In the Federal District of Mexico, surveillance began picking up cases of ILI starting 18 March. The number of cases has risen steadily through April and as of 23 April there are now more than 854 cases of pneumonia from the Mexican capital. Of the Mexican cases, 18 have been laboratory confirmed in Canada as Swine Influenza A/H1N1, while 12 of those are genetically identical to the Swine Influenza A/H1N1 viruses from California. The US has 8 confirmed cases within America and has tested atleast 14 specimens from Mexico, of which seven tested positive. Mean Prevalence of Influenza in U.S New England — 1.5% Mid-Atlantic — 2.9% East North Central — 1.9% West North Central — 1.7% South Atlantic — 2.2% East South Central — 2.5% West South Central — 4.8% Mountain — 1.5% Pacific — 3.0% National average- 2.4% The regions currently affected have always showed an infection rate higher than the national average. WHO has now activated its Strategic Health Operations Center (SHOC) -its command and control center for acute public health events. Life Cycle of Swine Flu virus- Birds like Ducks, geese and swans are common reservoirs of Influenza virus and can harbor the virus without showing symtoms of the disrease. 2
  3. 3. 4/25/2009 Pigs most commonly get infected with flu viruses from other pigs (swine flu), but also can get infected with flu viruses from birds (avian flu), and from people (human flu). This cross-species spread of flu viruses can lead to new types of flu viruses. Pigs may sometimes harbor the virus without exhibiting any overt symtoms. Signs of swine flu in pigs include: • coughing (“barking”) • discharge from the nose • sneezing • breathing difficulties • going off feed Studies have shown that 30% to 50% of commercial U.S. swine have been infected with swine flu. H1N1 and H3N2 swine flu viruses are endemic among pig populations in the United States.. Recent studies have shown that 15% to 25% of swine farmers might have been infected with swine flu viruses, as well as about 10% of veterinarians Why are Pigs important in this cycle? Replication of avian influenza viruses in pigs may allow them to adapt to and be able to efficiently infect mammals, and ultimately be 3
  4. 4. 4/25/2009 transmitted to people. In addition, pigs can serve as hosts in which two (or more) influenza viruses can undergo quot;genetic reassortment.quot; At this time, there are four main influenza type A virus subtypes that h ave been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H3 N2 and H1N1 viruses. The reassortant H3N2 and H1N1 viruses currently circulating widely and causing disease throughout the swine population of the United States all contain human influenza virus genes. From Pigs to Humans- 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). Families of swine owners who visit the farm atleast four times a week are also susceptible. Humans to other Humans- This is thought to occur in the same way as seasonal flu occurs in people, which is mainly person-to-person transmission through coughing or sneezing of people infected with the influenza virus. People may become infected by touching something with flu viruses on it and then touching their mouth or nose. Influenza normally affects the very young and the very old, but these age groups have not been heavily affected in Mexico. 4
  5. 5. 4/25/2009 Smcgee (http://www.flickr.com/photos/smcgee) Malingering (http://www.flickr.com/photos/malingering/) Symtoms- People infected with flu typically have fever (often high), cough, body aches, headaches, fatigue and runny or stuffy nose. Vomiting and diarrhea may also occur. Treatment– CDC recommends the use of oseltamivir or zanamivir for the treatment and/or prevention of infection with swine influenza viruses. These medicines should be started in the first 2 days of being ill to be most effective. Diagnosis- Diagnosis of swine influenza A (H1N1) virus infection should be considered in patients with febrile respiratory disease and who 5
  6. 6. 4/25/2009 1) live in San Diego and Imperial Counties, California, or Guadalupe County, Texas, or traveled to these counties or 2) who traveled recently to Mexico or were in contact with persons who had febrile respiratory illness and were in the two U.S. counties or Mexico in the 7 days preceding their illness onset. To diagnose swine influenza A infection, a respiratory specimen would generally need to be collected within the first 4 to 5 days of illness (when an infected person is most likely to be shedding virus). However, some persons, especially children, may shed virus for 10 days or longer. Identification as a swine flu influenza A virus requires sending the specimen to CDC for laboratory testing. History- Swine influenza viruses were first isolated in the United States in 1930. The most well known is an outbreak of swine flu among soldiers in Fort Dix, New Jersey in 1976. The virus caused disease with x-ray evidence of pneumonia in at least 4 soldiers and 1 death.The virus was transmit ted to close contacts in a basic training environment, with limited trans mission outside the basic training group. The virus circulated for a month and then disappeared just as mysteriously. The swine influenza A virus collected from the Fort Dix s oldier was named A/New Jersey/76 (Hsw1N1) 6
  7. 7. 4/25/2009 The number of isolates testing positive for Flu has been steadily increasing over the years. The H1N1 strain has been specialy noted for rapid increase since 2006-07. The Human H1N1 strain is genetically different from H1N1 strain seen in Swines. Infection Control of Ill Persons in a Healthcare Setting • Place all suspected cases in a single-patient room with the door kept closed. • The ill person should wear a surgical mask when outside of the patient room, and should be encouraged to wash hands frequently and follow respiratory hygiene practices. • Cups and other utensils used by the ill person should be washed with soap and water before use by other persons. • Standard, Droplet and Contact precautions should be used for all patient care activities, and maintained for 7 days after illness onset or until symptoms have resolved. • Personnel providing care to or collecting clinical specimens from suspected or confirmed cases should wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure. General Advice • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective. • Try to avoid close contact with sick people. • If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them. • Avoid touching your eyes, nose or mouth. Germs spread that way. 7
  8. 8. 4/25/2009 Main References- Center For Disease Control – http://www.cdc.gov/swineflu/key_facts.htm http://www.cdc.gov/media/transcripts/2009/t090423.htm World health organization – http://www.who.int/csr/don/2009_04_24/en/index.html National Pork board - http://www.pork.org/PorkScience/Documents/PUBLICHEALTH%20influ enza.pdf Medscape – http://www.medscape.com/viewarticle/408402_8 Mark IV Medical communications LLC. 20, Bharathi Park, 8th Cross Telephone: +91 422 4385520 Sai Baba Mission Post Fax: +91 422 2430963 Coimbatore 641011 Email: info@markivmedical.com Tamil Nadu, India Written by- Dr. Neelesh Bhandari MD (Path), PGP Human Rights Advisor (Medical Communications) Mark IV Medical Communications. 8