A Comprehensive Review on: Swine Flu


Miss. Sarika S. Lokhande*, Miss. Savita S. More

Gourishankar College of Pharmacy (D. Pharm) Limb, Satara

*Corresponding Author E-mail: sarikalokhande04@gmail.com



Swine flu, also called Hog or Pig Flu, is an infection caused by any one of the a number of types of Swine influenza virus (SIV) which is ordinary throughout pig population worldwide. The term "influenza" derived from Italian word" influence" was coined in 1357 AD as the disease was thought to be caused by influence of stars. India has had over 1,000 inveterate cases of swine flu so far that’s approximately one case per every million people in the nation. [1]. Swine flu virus is never before super flu virus but whenever three known virus such as a swine flu sprain, bird flu strain and human flu virus come together with each other than makes H1N1 swine flu virus which is not hazard if we take some keep against it such as a wear three layer mask on nose, wash the hands after coming home, not entail at place where big crowd attended.


KEYWORDS: Swine Flu, Influnza, H1N1, Awareness, Mode of spread. [2]




The orthodox swine flu virus an influenza type A (H1N1) virus was first inaccessible from a pig in 1930. Swine flu viruses cause high level of illness, but low death rates in pigs. Approximating all influenza viruses, swine flu viruses change frequently. Pigs can also be infected by avian influenza and human influenza viruses. The H1N1 virus (swine flu) is a new flu virus strain that has caused a universal pandemic in humans from June 2009 to August 2010.The Centers for Disease Control and avoidance now call the virus 2009 H1N1, an acute and highly communicable respiratory disease of swine caused by the orthomyxo virus thought to be the similar virus that caused the 1918 influenza pandemic an sensitive febrile extremely communicable viral disease.[3]


A highly communicable form of human influenza caused by a filterable virus identical or related to a virus previously secluded from infected swine. The respiratory infection popularly known as swine flu is caused by an influenza virus first recognized in spring 2009, near the end of the usual Northern Hemisphere flu season.


World Health Organization has reported 25,288 laboratory inveterate cases of influenza A/H1N1 infection with 139 deaths from 73 countries spread over America, Europe, Asia and Australian continent. [4]


History of Swine Flu-

Swine flu, also called Hog or Pig Flu, is an infectivity caused by any one of the some types of Swine influenza virus (SIV) which is ordinary throughout pig population universal. The term "influenza" consequent from Italian word" influence" was coined in 1357 AD as the disease was consideration to be caused by influence of stars. Influenza pandemics are believed to have occurred at impulsive intervals for many centuries. Outbreaks of swine flu are ordinary and cause important inexpensive losses. Influenza, the flu, is thought to have been around for a few thousand years. Hippocrates, who is painstaking to be the father of modern medicine, has described the symptoms of the flu in 412 B.C at Printouts in North Greece.[5]


1. In 855 Ebn al atir mentions a vituperative epidemic similar to flu that started in Central Asia and spread across Persia.


2. In 1485 an illness with flu like symptoms killed thousands of people in Britain, as well as the mayor.


3. In 510 a flu virulent disease originated in Africa and spread across Europe.


4. In 1580 a virulent disease originated in the North Africa during summer, spread to Sicily, and then up through Italy, through Europe and to North America. It had a high humanity rate and killed 9000 people in Rome alone.


5. In 1688, an outbreak, described as being like the plague because of the death toll, swept through England, Ireland and Virginia.


6. In 1699 an influenza eruption occurred in Europe and America and Massachusetts. The sickness extensive to approximately all families


7. In 29 a virulent disease originated in Russia, and re-emerged in Sweden in September and in Vienna in October. In November it spread across Europe, and reached America in 1732. Deaths were the majority abundant along with the elderly and pregnant women.[6]



The three genera of influenza viruses that cause human flu, two as well basis influenza in pigs, with influenza-A being frequent in pigs and influenza-C being rare 3. Influenza-B has not been reported in pigs. Within influenza-A and influenza-C, the strains create in pigs and humans are mostly divergent, even though due to reassortment there have been transfers of genes among strains crossing swine, avian and human species limitations.[7]



Swine influenza is recognized to be caused by influenza –a subtype H1N1, H1N2 4, H2N35, H3N16, In a pig three influenza- A virus subtypes worldwide7. In the United States, the h1n1 subtype was entirely widespread among swine populations before 1998; however, since late august 1998, h3n2 subtypes have been inaccessible from pigs. As of 2004, h3n2 virus isolates in US and turkey stocks were triple reassortants, containing genes from human, swine and avian lineages.[8]


influenza –C:

Influenza-c virus infects both humans and pigs, but do not infect birds. Transmissions between pigs and human have occurred in the past. For example, influenza-c caused minute outbreaks of a soft form of influenza amongst children in Japan and California.[9]



Primary, the influenza viruses (types A, B, C) are enveloped RNA viruses with a segmented genome; this means the viral RNA genetic code is not a solitary strand of RNA but exists as eight unusual RNA segments in the influenza viruses. A human (or bird) influenza virus can infect a pig respiratory cell at the similar point in time as a swine influenza virus; several of the replicating RNA strands from the human virus can get erroneously enclosed inside the enveloped swine influenza virus. For example, one cell could contain eight swine flu and eight human flu RNA segments. The entirety number of RNA types in one cell would be 16; four swine and four human flu RNA segments could be included into one element, making a viable eight RNA segmented flu virus from the 16 accessible segment types. Different combinations of RNA segments can result in a new subtype of virus (known as antigenic shift) that may have the capability to preferentially contaminate humans but still show distinctiveness unique to the swine influenza virus (Figure 2). It is even probable to include RNA strands from birds, swine, and human influenza viruses into one virus if a cell becomes contaminated with all three types of influenza (for example, two bird flu, three swine flu, and three human flu RNA segments to produce a viable eight-segment new type of flu viral genome)[10]. Formation of an innovative viral type is painstaking to be antigenic shift; minute changes in an individual RNA segment in flu viruses are termed antigenic drift and result in slight changes in the virus. However, these can accumulate above time to produce adequate slight changes that cumulatively alter the virus antigenic makeup more time (usually years). Second, pigs can play a exclusive role as an intermediary host to new flu types because pig respiratory cells can be unhygienic directly with bird, human, and other mammalian flu viruses. accordingly, pig respiratory cells are able to be infected with lots of types of flu and can function as a "mixing pot" for flu RNA segments (Figure 3)[11]. Bird flu viruses, which frequently infect the gastrointestinal cells of lots of bird species, are shed in bird faeces. Pigs can pick these viruses up from the atmosphere and seem to be the most important way that bird flu virus RNA segments enter the mammalian flu virus inhabitants. (McKinney WP et al, 1990)[12]



Fig 2. Shows Pathophysiology of Swine Flu (Heinen, P. (2003)


Transmission of Virus to Human:

Transmission of the virus from pigs to humans is not widespread and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If spread does cause human influenza, it is called zoonotic swine flu. People with regular exposure to pigs are at improved risk of swine flu infection. The meat of an infected animal poses no risk of infection when precisely cooked. [13]


Symptoms of swine flu infections include (Antonovics J, 2006):

1. Fever, which is typically high, but unlike seasonal flu, is occasionally absent.

2. Cough

3. Runny nose or stuffy nose

4. Sore throat

5. Body aches

6. Headache

7. Chills

8. Fatigue or tiredness, which can be extreme

9. Diarrhoea and vomiting, sometimes, but more commonly seen than with seasonal flu

10. Signs of a further serious swine flu infection might include pneumonia and respiratory failure.[14]


Serious Swine Flu Symptoms (Schmeck , Harold M. 1976):

Further serious symptoms that would indicate that a child with swine flu would need imperative medical attention include:

·         quick breathing or trouble breathing

·         Bluish or gray skin color

·         Not drinking enough fluids

·         Severe or persistent vomiting[15]

·         Not waking up or not interacting

·         Being so irritable that the child does not want to be detained

·         Flu-like symptoms improve but then return with fever and worse cough

·         Unusual tiredness

·         Headache

·         Runny nose

·         Sore throat [16]


Fig 1: Symptoms of swine



Influenza virus is present in respiratory secretions of infected persons. As a result, influenza virus can be transmitted through sneezing and coughing via large-particle droplets [13, 14]. Transmission via contact with surfaces that have been contaminated with respiratory droplets or by aerosolized small-particle droplets may also occur, although these modes of transmission have not been proven. In addition to respiratory secretions, certain other body fluids (e.g. diarrheal stool) should also be measured potentially infectious. [17]


How infectious is it?

Since this virus is new, people have no immunity to it so it will spread more rapidly and extensively than the seasonal flu. The virulent disease situation could mean lots of people become sick at the same time and this could have a big impact on our day-to-day lives and place substantial pressure on the health services. Infected person may be able to infect others start one day before symptoms develop and up to seven or more days after becoming sick.[18]



Transmission between pigs:

Influenza is quite ordinary between pigs, with about half of breeding pigs having been uncovered to the virus in the US. Antibodies to the virus are also frequent in pigs in other countries. The main route of transmission is through direct contact between infected and uninfected animals. These close contacts are predominantly frequent during animal transmit. Exhaustive farming may also enhance the risk of transmission as the pigs are raised in very close proximity to each other. The direct of the virus almost certainly occurs either by pigs touching noses, or through dried mucus. Airborne transmissions through the aerosols produced by pigs coughing or sneezing are also a significant means of infection. [19]


Mechanism of Viral Infection:

It can be represented by the diagram which is given below as:


The 469 amino acid long neuraminidase (NA) protein is essential for release of the viral particle from the outer membrane of infected cells by cleaving sialic acid from host glycoproteins that are renowned by the viral hemagglutinin. As a type II transmembrane protein, it is N-terminally attached to the membrane. It consists of a tiny cytoplasmic tail at the N-terminus (residues 1 to 6) followed by the transmembrane region (residues 7 to 34) that is also dependable for translocation of the protein. Subsequently, a most probably unstructured linker region (residues 35 to 82) connects the membrane anchor to the catalytic neuraminidase domain. Such unstructured linker regions are affluent in small and polar residues and often harbour sites for posttranslational modifications. [20] Probable posttranslational modification sites in the neuraminidase of the innovative strain are glycosylation motifs involving N88, N146 and N235, which correspond to residues that are also glycosylated in other subtype neuraminidases. However, the minimal and non-specific consensus motif of glycosylation sites (Nx [ST]) is found in total 8 times in the novel strain sequence with an apparent clustering (50%) in the unstructured linker region. entertainingly, another putative novel glycosylation site N386, which is limited to the novel strain, would be accessible on the surface, as seen in the structural models. Comparing among all strains, the sequence variation is biggest in the linker region, including huge deleted segments. Nevertheless, this region harbours a cysteine that can be aligned over multiple NA subtypes and is conserved in N1-N5 and N8, but not in N6, N7 and N9.[21] previous reports assume that, at least in related viruses, cysteines in the non-globular region could be concerned in intermolecular disulfide bridges. Otherwise, by similarity to other influenza proteins such as hem agglutinin and M2 protein, it cannot yet be excluded that cysteine C49 is palmitoylated and that the anchor localizes the protein to lipid rafts.


Figure 3: Viral infection cycle


Difference between Cold and Swine Flu



Swine flu


Fever is rare with cold

Fever is frequently present with the flu in up  to 80% of all swine flu. A temperature of 100f r higher for 3 to 4 days


A hacking productive (mucus producing) cough

A non productive cough is frequently present with the swine flu


Chills are uncommon

60% of the people who have swine flu experience chills


Tiredness is faily mild

Tiredness is restrained to severe


Slight body ache and pains can be part of cold

Severe aches and pains are ordinary


Headache is fairly uncommon

Headache is common and experienced by 80% of cases


Different System of Medicine:


Ayurveda promotes the concept that if one's immune system is strong, then even if the body is uncovered to viruses, one will not be exaggerated. During a pandemic or an epidemic, Ayurveda emphasizes on the immunity of people living in regions precious by viruses. This branch of medicine promotes the intake of particular herbs or decoctions to increase the immunity level of the people. Ayurvedic remedies comprise pure natural herbs which are efficient in preventing swine flu. Moreover, the herbs are used to relieve swine flu symptoms, and boost the immune system against the H1N1 virus. Ayurvedic treatment for swine flu involves This is done by prescribing a variety of digestive fire strengthening herbs such as Guduchi (licorice), Tulasi (Holy Basil), Sahadevi, Neem (Indian Margosa Tree), Shunthi (ginger), Pippali (pepper) etc. Once the digestive fire is corrected, medicines such as Triphala, Rasna, Eranda, Guggulu can be prescribed to relieve the symptoms. Ayurvedic treatment for swine flu involves: Basil, Ginger and Garlic, Gooseberry and AloeVera, Camphor and Eucalyptus Oil.[22]



Considering that the Swine Flu virus produces symptoms similar to the human influenza virus, the following homeopathy medicines may provide evidence useful in cases of swine influenza: Gelsemium, Baptisia, Eupatorium perfoliatum, Sabadilla, Arsenicum, Arsenicum iodide, Dulcamara, Bryonia

Phosphorus, Rhus toxicodendron.


Siddha System:

The conventional Siddha system has very efficient medicines for the prevention and treatment of swine flu exclusive of any side effects on the users a decoction made of Tulsi (Ocimum tenuiflorum), Karpooravalli (Plectranthus amboinicus), Black Pepper (Piper nigrum), Cloves (Eugenia aromaticum), Cardamom  (Elettaria cardamomum) and Honey (Apis mellifera) would be efficient for preventing the swine flu. The ingredients should be boiled in one llitre of waterand then filtered. An adult should take 150ml pf the filtered portion once in a day while a child could be given 75ml. It could be taken for abiut 7 to 10 days .[23] Other siddha pepration for treating an contaminated person includes crushing humdread gm each of Nilavembu, Seenthil, Adothoda, Vishnu Karanthai, Parpadhan to make into a powder. Take 50 grams of the powder and heat it adding 1litre of water. The infected adult should take 150ml while a child could be given 75 ml for 7 to 10 days.[24]



1. A rapid test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza A or B virus. Most of the tests can differentiate between A and B types. The test can be negative (no flu infection) or positive for type B, the flu is not likely to be swine flu (H1N1). If it is positive for type A, the person could have a predictable flu strain or swine flu (H1N1). However, the precision of these tests has been challenged, and the U.S. Centers For Disease Control and Preventation (CDC) has not completed their relative studies of these tests, however, a innovative test developed by the CDC and a commercial company supposedly can detect H1N1 reiably in about one hour; as of October 2009, the test is only available to the military. [25]


2. Swine flu (H1N1) is definitively diagnosed by identifying the particular antigens related with the virus type. In general, this test done in a particular laboratory and is not done by many doctor’s offices or hospital laboratories. However, doctor’s offices are able to send specimens to specialize laboratories if necessary. Because of the larger number of novel H1N1 swine flu cases (as of October 2009, the vast  majority of flu cases (about 99%) are due to novel H1N1 flu Viruses), the CDC recommends only hospitalizes patient’s flu virus strains be sent to reference labs to be identified.[26]


Future Aspects:

Computer-assisted vaccine design:

A innovative parameter has been defined to measure the antigenic distance between two H3N2 influenza strains. This parameter was used to measure antigenic distance between circulating H3N2 strains and the closest vaccine constituent of the influenza vaccine.[27] For the data between 1971 and 2004, the measure of antigenic distance correlated better with effectiveness in humans of the H3N2 influenza A annual vaccine than did current measures of antigenic distance such as phylogenetic sequence analysis or ferret antisera inhibition assays.[28] This measure of antigenic distance could be used to guide the design of the annual flu vaccine. The antigenic distance combined with a multiple-strain avian influenza transmission model was used to study the threat of instantaneous introduction of multiple avian influenza strains. Population at Risk (PaR) can be used to quantify the risk of a flu pandemic and to calculate the enhancement that a multiple vaccine offers[29].



The clusters of milder infections in the US propose the virus is spreading readily among people. The US Centers for Disease Control and Prevention (CDC) says this strain is so dissimilar from accessible human flu viruses that most people have no immunity to it. H1N1 influenza or swine flu is a communicable disease that is caused by the influenza virus. Infection with the H1N1 influenza virus can result in severe illness and life- threatening complications. Symptoms of H1N1 flu are similar to those of the frequent flu and scientists are vigorously studying the situation to better appreciate its range of symptoms and how it is spread. So through this article we tried to collect the brief information about this exacting disease. We can play most important role in the prevention of the transmission of this disease. All in all this situation is likely to get inferior in the subsequently couple of months and we should now focus our efforts on helping developing countries like India and also saving as many as we can, too carry on life if an extraordinary amount of people die.



Author are thankful to Gourishankar college of D pharma, Limb Satara for providing valuable help and authors are also Thankful Mr. Raje V.N, Principal, Gourishankar college of D pharma, Limb Satara for providing necessary guidance for this work



1.        Guo Y., Jin F., Wang P., Wang M., Zhu J.M. (1983). "Isolation of Influenza C Virus from Pigs and Experimental Infection of Pigs with Influenza C Virus". Journal of General Virology 64: 177–82.

2.        Kimura H, Abiko C, Peng G, et al. (1997). Interspecies transmission of influenza C virus between humans and pigs. Virus Research 48 (1): 71–9.

3.        Centers for Disease Control and Prevention, Update: Drug susceptibility of Swine Origin Influenza A (H1N1) viruses. Morb Mortal Wkly Rep 58, 2009, 433–435.

3.        Ma, W., A.L. Vincent, M.R. Gramer, C.B. Brockwell, K.M. Lager and B.H. Janke, 2007. Identification of H2N3 Influenza A Viruses from Swine in the United States. Proc. Nat. Acad. Sci., 104(52): 20949-20954.

4.        Grayson ML, Wessling S. Management of infectious disesases. MJA 2002; 176(5): 202-203.

5.        McKinney WP, Volkert P, Kaufman J (1990). Fatal swine influenza pneumonia during late pregnancy. Archives of Internal Medicine 150 (1): 213–5. doi:10.1001/archinte.150.1.213

6.        Ma W, Vincent AL, Gramer MR, Brockwell CB, Lager KM and Janke BH. Identification of h2n3 influenza a viruses from swine in United States. Proc. Nat. Acad. Sci. 2007; 104(52):20949-20954.

7.        Kilbourne E D 2006 Infl uenza pandemics of the 20th century; Emerg. Infect. Dis. 12 9–14

8.        Acharya Yadavji Trikamji. Sushruta Samhita Vol. I. Chaukhamba Sanskrit Sansthana. Varanasi. 1994. Su.Ni. 5/33- 34.

9.        Kothalawala, H., M.J. Toussaint and E. Gruys, 2006. An Overview of Swine Influenza. Vet. Q., 28(2): 46-53.

10.      Myers, KP, Olsen, CW, Gray, GC. Cases of swine influenza in humans: a review of the literature. Clin Infect Dis 2007; 44:1084.

11.      Schmeck, Harold M. (1976). Ford Urges Flu Campaign To Inoculate Entire U.S. The New York Times.

12.      Press release. Government Reviews Preparedness for Swine Flu. Ministry of Health and Family welfare. April 27, 2009

13.      Understanding the symptoms of the common cold and influenza". Lancet Infect Dis 5 (11): 718–25

14.      Tim P 2008 Spatial epidemiology of an H3N2 swine infl uenza outbreak; Can. Vet. J. 249 167–176

15.      Lynch, J.P. and E.E. Walsh, 2007. Influenza: Evolving Strategies in Treatment and Prevention. Semin. Respir. Crit. Care Med., 28(2): 144-158.

16.      Acharya Yadavji Trikamji. Sushrut Samhita Vol. II. Chaukhamba Sanskrit Sansthana. Varanasi.1994. Su. Uttara. 39/45.

17.      Antigenic and genetic characterization of influenza C viruses which caused two outbreaks in Yamagata City, Japan, in 1996 and 1998". J Clin Microbiol 40 (2): 422–9.

18.      Vana G, Westover KM (2008). "Origin of the 1918 Spanish influenza virus: a comparative genomic analysis. Molecular Phylogenetics and Evolution 47 (3): 1100–10.

19.      Kimura HC and Peng G. Interspecies Transmission of influenza C Virus between Humans and Pigs. Virus Res. 1997; 48(1): 71-79.

20.      Hospitalized Patients with Novel Influenza A (H1N1) Virus Infection-California, April-May, 2009. MMWR Morb Mortal Wkly Rep., 58: 536

21.      Ito T, Couceiro J N, Kelm S, Baum L G, Krauss S, Castrucci M R, Donatelli I, Kida H, Paulson J C, Webster R G and Kawaoka Y 1998 Molecular basis for the generation in pigs of infl uenza A viruses with pandemic potential; J. Virol. 72 7367–7373

22.      CHEN Min-jun,Wang Hui.China ICU Gram-negative bacteria resistance monitoring study for 7 years [J].Chinese Medical Journal, 2003,83:375 381.

23.      "Epidemiology and pathogenesis of influenza". J Antimicrob Chemother 44 Suppl B: 3–9.

24.      Bonin, E., Brehove, T., Kline, S., Misgen, M., Post, P., Strehlow, A., and Yungman, J. (2004). Health Care for the Homeless Clinicians’ Network, National Health Care for the Homeless Council, Retrieved September 29, 2007

25.      Fuyuno I, Tamiflu side effects come under scrutiny, Nature, 446, 2007, 358–359.

26.      "Swine influenza virus infections. Transmission from ill pigs to humans at a Wisconsin agricultural fair and subsequent probable person‐to‐person transmission". JAMA 265 (4): 478–81.

27.      Dawood, F.S., S. Jain and L. Finelli, 2009. Emergence of a Novel Swine-origin Influenza A (H1N1) Virus in Humans. N Engl. J. Med., 360: 2605.

28.      Myers KP, Olsen CW, Gray GC (2007). Cases of swine influenza in humans: a review of the literature. Clinical Infectious Diseases 44 (8): 1084–8.

29.      Bonin, E., Brehove, T., Kline, S., Misgen, M., Post, P., Strehlow, A., and Yungman, J. (2004). Health Care for the Homeless Clinicians’ Network, National Health Care for the Homeless Council, Retrieved September 29, 2007.







Received on 17.07.2019            Modified on 27.09.2019

Accepted on 25.10.2019            © A&V Publications All right reserved

Asian J. Res. Pharm. Sci. 2019; 9(4):282-287.

DOI: 10.5958/2231-5659.2019.00045.6