Mankind has always been under the threat of a new, more dangerous virus emerging and causing massive epidemics. Our modern transportation systems make it all the easier for such a virus to spread quickly throughout the world. Man's constant exploration and encroachment in previously inaccessible parts of the world make it more likely that something nasty might emerge. However, it is worth noting that viruses have always been with us, evolving ways to reproduce and spread. Viruses, like humans, are just playing the evolution game. 
Flu is short for influenza. The name goes back hundreds of years when the disease was thought to be caused by supernatural "influences". Many people describe any nasty lung infection as flu, but only specific lab tests can give a proper diagnosis. There are several different viruses (and bacteria) which may infect the lung, but true flu is caused by orthomyxoviruses, of which there are three types, designated A, B, and C. Influenza C infects people when they are young and rarely causes serious illness. Type B occasionally causes local outbreaks of flu and is usually confined to youngsters. Influenza A is very important to mankind as this is the type of virus that has caused worldwide pandemics. The influenza virus is notoriously known for its unique ability to cause recurrent epidemics and global pandemics during which acute febrile respiratory illness occurs explosively in all age groups. The influenza virus, as a pathogenic agent for humans, has been circulating in the human population since at least the sixteenth century (Cox & Kawaoka 1998) leading to recurrent epidemics of febrile respiratory disease every 1 to 3 years. In addition, each century has seen some pandemics rapidly progressing to involve all parts of the world due to emergence of a novel virus to which the overall population holds no immunity.

Transmission
 In mammals, influenza viruses are transmitted in aerosols created by coughing and sneezing and by contact with nasal discharges, either directly or on fomites. Close contact and closed environments favor transmission. Occasionally, these viruses cross species barriers. Recent serological evidence suggests that most people who have contact with pigs. Pigs are readily infected with human influenza A viruses, but most strains do not spread widely. Person to person transmission occurs with the H1N1 virus that is currently circulating in humans. People who work with poultry and swine, especially those with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur. Vaccination of these workers against influenza and surveillance for new influenza strains among this population may therefore be an important public health measure. The estimated period of communicability of virus is from 1 day before the symptoms appear, to as long as 7 days after their onset. It is possible that people may shed virus for as long as they are ill.

Symptoms
Common symptoms include: lethargy, lack of appetite, running nose, sore throat, coughing, nausea, and diarrhea.  In some cases, swine influenza can result in a severe pneumonia. Symptoms of influenza generally appear between two to four days after exposure.

Diagnosis
Influenza A infections can be diagnosed by virus isolation. These viruses can be isolated in cell lines or chicken embryos, and are identified by haemagglutinition inhibition tests. Nucleic acids can be detected in respiratory secretions by Reverse Transcriptase Polymarase Chain Reaction assays and antigen can be detected in respiratory secretions by immunoflorence or ELISA. Infections can also be diagnosed retrospectively by serology with a fourfold rise in titer.

Treatment
Supportive care for swine influenza in human includes fluids and rest .Four antiviral drugs are available for influenza treatment viz: Amantadine and Rimantadine as well as Zanamivir and Oseltamivir, are active against some influenza A viruses, if treatment is begun in first 48 hours. Testing must be done to determine each influenza virus’s susceptibility to antiviral drugs. Beside antivirals, supportive care at home or in a hospital focuses on controlling fevers, relieving pain and maintaining fluid balance, as well as identifying and treating any secondary infections or other medical problems. 
 
Preventive measures
Prevention is the best option.
Cover your nose and mouth with a tissue paper while coughing or sneezing.
Wash your hands often with soap and water.
Avoid touching your nose, eyes or mouth.
Keep safe distance from patients.
Avoid crowded places.
Take rest if suffering from cold like symptoms.
Use N95 masks to reduce the risk.
Keep household surfaces clean and hygienic.
Contact with people from affected area should be cautionary.
Never hesitate to consult a doctor.

(Authors are, PG Scholars from Division of Vet. Surgery & Microbiology SKUAST-K respectively. Feed back at mohsingazi9975@gmail.com)

Lastupdate on : Wed, 23 May 2012 21:30:00 Makkah time
Lastupdate on : Wed, 23 May 2012 18:30:00 GMT
Lastupdate on : Thu, 24 May 2012 00:00:00 IST