July 29, 2009 4:43:14 am
Incubation Period
One to seven days
Symptoms
Manifestations of H1N1 influenza (swine flu) are similar to those of seasonal influenza. Patients present with symptoms of acute respiratory illness,including at least two of the following
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* Fever
* Cough
* Sore throat
* Body aches
* Headache
* Chills and fatigue
Diarrhea and vomiting (possible)
Persons with these symptoms should call their health care provider promptly. If an antiviral agent is warranted,it should ideally be initiated with 48 hours from the onset of symptoms (see Medications),according to Dr R R Pardeshi,cheif medical officer,PMC. The duration of illness is typically four to six days. The infectious period for a confirmed case is defined as one day prior to the onset of symptoms to seven days after onset. In children ,signs of severe disease include apnea,tachypnea,dyapnea,cyanosis,dehydration,altered mental status and extreme irritability.
Transmission
Influenza viruses can be directly transmitted from pigs to people and from people to pigs.
Human infection with flu viruses from pigs are most likely to occur when people are in close proximity to infected pigs,such as in pig barns and livestock exhibits housing pigs at fairs.
Human-to-human transmission of influenza A (H1N1) can also occur. At present,in India we have two indigenous cases. This is thought to occur in the same way as seasonal flu,which is mainly person-to-person transmission through coughing or sneezing by people infected with the influenza virus.
Disease spreads very quickly among the population especially in crowded places.
Cold and dry weather enables the virus to survive longer outside the body than in other conditions and,as a consequence,seasonal epidemics in temperate areas appear in winter.
People may become infected by touching / handling something contaminated with flu viruses on it and then touching their mouth or nose.
Influenza A (H1N1) viruses are not transmitted by food.
Eating properly handled and cooked pork (at an internal temparature of > 160 degree Fahrenheit) and pork products is safe.
Treatment
For Adults: For case- Tab Oseltamivir 75 mg B D for five days
For Chemoprophylaxis – Tab Oseltamivir 75 mg O D for 10 days
For children:Syrup Oseltamivir as per doctor’s advice.
Diagnosis of H1N1
For diagnosis of influenza A (H1N1) infection,respiratory specimen would generally need to be collected within the first four to five 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.
Sample collection and laboratory diagnosisSample Collection and handling is same as for human avian flu or seasonal influenza like illness.
Sample Collection: Should be done by the treating doctor,who is managing the case.
Preferred respiratory samples:Nasopharyngeal swab and throat swab.
Storage of samples:All samples should be kept at two to eight degrees centigrade until they can be placed at -70 degrees centigrade
Transportation of samples:Clinical samples should be transported on dry ice in triple packaging. All samples should be labeled clearly and include patient’s complete information and should be sent to NIV,Pune or NICD,Delhi within 24 hours for further investigations.
Laboratory biosafety measures should be followed for collection,storage,packaging and shipping of influenza samples.
Available Laboratory tests:
Rapid Antigen tests: not as sensitive as other available tests.
RT-PCR
Virus isolation
Virus genome Sequencing
Four-fold rise in swine influenza A (H1N1) virus specific neutralizing antibodies.
It is important to note that samples from all cases,once the Pandemic starts,are not required to be tested.
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