H1 n1 aftermath

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SWINE FLU-A REVIEW” SWINE FLU-A REVIEW” - By Shrutika J. Khobare

Transcript of H1 n1 aftermath

“ “SWINE FLU-A REVIEW”SWINE FLU-A REVIEW”

- By Shrutika J. Khobare

INTRODUCTION• Swine influenza H1N1 flu, swine flu, hog flu, and pig flu is an infection by any one of several types of

swine influenza virus. Swine influenza virus (SIV) is any strain of the influenza family of viruses that is endemic in pigs.

• the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2, and H2N3.Electron microscope image of the reasserted H1N1 influenza virus photographed at the CDC Influenza Laboratory. The viruses are 80–120 nanometers in diameter.

• Total Infections as on 17th August: Top 10 Cities

• A vaccine that will prove effective against the new H1N1 swine influenza virus is still awaited. In India, two more pharmaceutical companies; Bharat Biotech, and Panacea Biotech have also started working on developing the vaccine along with Serum Institute of India against the novel H1N1 virus and have also submitted their plans to launch the vaccine by March 2010.The issue of development of a suitable vaccine has been addressed aggressively by the sharing of updated information between different countries. The most urgent aspect required for preventing the spread of the virus is planning and coordination between various countries.

HISTORY• Swine influenza was first proposed to be a disease related to human influenza during the 1918 flu pandemic, when pigs became sick at the

same time as humans.• The H1N1 form of swine flu is one of the descendants of the strain that caused the 1918 flu pandemic

Table 3.1: human cases of influenza • In order to know the human cases of H1N1 influenza in the European region, one can look at the table 3. One can decipher from the table

that most of the human cases of influenza A (H1N1) were reported from Spain (57) and United Kingdom (27). Cases were found among people who have travelled to affected areas in the Americas. On 4 May 2009, WHO/Europe was informed of the first laboratory-confirmed case of influenza A (H1N1) in Portugal.

• The new strain of the virus has spread beyond Mexico and the US, with confirmed cases in eighteen countries and suspected cases in forty-two. Officials from World Health Organisation (WHO) and Centre for Disease Control and Prevention (CDC) believe that the outbreak may become pandemic. Prior to the swine flu outbreak, the WHO worldwide pandemic alert was set at Phase 3 due to H5N1 "avian flu", which spread widely in birds with occasional cases in humans. After the outbreak of "swine flu", WHO raised its alert level to Phase 5 out of 6 possible, which it defines as a "signal that a pandemic is imminent."

CLASSIFICATION

A.Influenza C:

Influenza C viruses infect both humans and pigs, but do not infect birds. Transmission between pigs and humans have occurred in the past. For example, influenza C caused small outbreaks of a mild form of influenza amongst children in Japan and California.

B.Influenza A:

Swine influenza is known to be caused by influenza A subtypes H1N1, H1N2,H2N3,H3N1,and H3N2. In pigs, three influenza a virus subtypes (H1N1, H1N2, and H3N2) are the most common strains worldwide.In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.

C.Surveillance:

Although there is no formal national surveillance system in the United States to determine what viruses are circulating in pigs, there is an informal surveillance network in the United States that is part of a world surveillance network. Veterinary, Tracey McNamara, set up a national disease surveillance system in zoos because the zoos do active disease surveillance and many of the exotic animals housed there have broad susceptibilities.

CLASSIFICATION:

PHATHOLOGY

• Influenza Virus:In 2009 new H1N1 influenza virus causes illness in people. This new virus was first detected in

people in the United States in April 2009. This virus is spreading from person-to-person worldwide, probably in much the same way that regular seasonal influenza viruses spread. On June 11, 2009, the World Health Organization (WHO) announced that a pandemic of 2009 H1N1 flu was underway. “Pandemic” means that an infectious disease, in this case Swine Flu, has spread all over the world in a very short period of time and is continuing to infect people. Pandemics due to influenza occur about 3-5 times per century, and are generally much more severe than routine “seasonal” flu. The worst pandemic in world history was caused by the “Spanish Flu” of 1918, which caused the deaths of 500,000 Americans and 50-100 million people throughout the world.

Fig: 5.1-Stucture of H1N1 virus

• Henipaviruses are pleomorphic (variably shaped), ranging in size from 40 to 600 nm in diameter.43 They possess a lipid membrane overlying a shell of viral matrix protein.

Fig : Structure of henipaviruses

Fig: The henipavirus genome and products of the P gene

• Hendra Virus:

• Emergence:

Hendra virus (originally Equine morbillivirus) was discovered in September 1994 when it caused the deaths of fourteen horses, and a trainer at a training complex in Hendra, a suburb of Brisbane in Queensland, Australia.

• Pathology:

Flying foxes are unaffected by Hendra virus infection. Symptoms of Hendra virus infection of humans may be respiratory, including haemorrhage and oedema of the lungs, or encephalitic resulting in meningitis.

• Virus Characteristics:

• Virus Origins:

On June 23, 2009 The New York Times reported that U.S. federal agriculture officials, "contrary to the popular assumption that the new swine flu pandemic arose on factory farms in Mexico," now believe that it "most likely emerged in pigs in Asia, but then traveled to North America in a human.

• Sources of contamination:

• Virulence:The virulence of swine flu virus is mild and the mortality rates are very low. In mid-2009 the US

Centers for Disease Control and Prevention (CDC) noted that most infections were mild, similar to seasonal flu, and that recovery tended to be fairly quick The number of deaths as of September 2009 is sometimes misleadingly said to be a tiny fraction of the annual number of deaths from seasonal flu.

• Mutation:On November 20, 2009 the Norwegian Institute of Public Health released a statement saying that they had

discovered a potentially significant mutation in the H1N1 influenza strain that could be responsible for causing the severest symptoms among those infected. In the statement they said "The mutation could be affecting the virus' ability to go deeper into the respiratory system, thus causing more serious illness".

• Resistance:As of December 2010, the World Health Organization (WHO) reported 314 samples of

2009 pandemic H1N1 flu tested worldwide have shown resistance to oseltamivir (Tami flu). This is not totally unexpected as 99.6% of the seasonal H1N1 flu strains tested have developed resistance to oseltamivir

• Species Affected:Humans:

Humans have been affected since early 2009. The November 27, 2009 worldwide update by the U.N.'s World Health Organization (WHO) states that "more than 207 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 7,820 deaths". The WHO has also tracked more than 622,482 laboratory-confirmed cases of H1N1.

• Nomenclature: Some authorities object to calling the flu outbreak "swine flu". U.S. Agriculture Secretary expressed concerns

that this would lead to the misconception that pork is unsafe for consumption. The CDC began referring to it as "Novel influenza A (H1N1)"; "A/H1N1" is sometimes used.

• Genetics:

Symptoms of Swine Flu in humans

INFECTION PERIOD

Fig: Virus Replication/Infection Time Period

DIAGNOSIS Step1: The first symptoms of swine flu include coughing, lack of

appetite and lethargy. Fever over 100 degrees Fahrenheit is typical. Step2: Watch for the advanced signs of Swine Flu. As the infection

advances, some people will experience sore throat, body aches, runny nose, vomiting, nausea and diarrhea.

o Bluish color of the skin o Troubled, Fast Breathing o Does not want to drink fluids o Fever and a rash o Refusing to be held because of irritability o Difficulty waking up or little interaction

DIAGNOSIS Ctd.. Urgent medical attention is required for adults who show signs of

Symptoms listed in Steps 1, 2 and any of the following:

(a)Sudden confusion or dizziness

(b)Shortness of breath or difficult breathing

(c)Persistent, severe vomiting

(d)Pressure or pain the abdomen or chest Step3: Call your Doctor. If you are experiencing many of the

symptoms listed in Steps 1 and 2, contact your doctor to discuss if influenza treatment or testing is recommended.

Step4: Final Diagnosis by a Doctor. Only a Doctor can diagnose swine flu by running tests. There are two tests that are conducted to aid in the confirmation of a diagnosis. Both tests require a sample of secretions from the nose and mouth (known as a nose and throat swab) and must be tested in the first 24-72 hours after the first symptoms appear.

TRANSMISSION OF VIRUS TO HUMAN

• Figure: Models for the role of pigs in interspecies transmission and adaptation of influenza viruses. Pigs serve as reservoirs of H1N1, H3N2 and H1N2 influenza viruses which can be transmitted to humans.

MECHANISM OF VIRAL INFECTION

MECHANISM OF VIRAL INFECTION Ctd…

• 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 glycoprotein that are recognized by the viral hemagglutinin.

• As a type II transmembrane protein, it is N-terminally attached to the membrane. It consists of a tiny cytoplasm tail at the N-terminus (residues 1 to 6) followed by the transmembrane region (residues 7 to 34) that is also responsible for translocation of the protein.

• Next, a presumably unstructured linker region (residues 35 to 82) connects the membrane anchor to the catalytic neuraminidase domain .Such unstructured linker regions are rich in small and polar residues and often harbour sites for posttranslational modifications.

• Probable posttranslational modification sites in the neuraminidase of the new 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 is found in total 8 times in the new strain sequence with an apparent clustering (50%) in the unstructured linker region.

PREVENTION OF TRANSMISSION TO HUMANS

• Transmission occurs mainly in swine farms where farmers are in close contact with live pigs. The use of vaccines on swine to prevent their infection is a major method of limiting swine to human transmission. Risk factors that may contribute to swine-to-human transmission include smoking and, especially, not wearing gloves when working with sick animals -- thereby increasing the likelihood of subsequent hand-to-eye, hand-to nose or hand-to-mouth transmission. Few precautions to be taken by humans so as to prevent transmission are given below as:

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 hand cleaners are also effective.

Avoid touching your eyes, nose or mouth. Germs spread this way. Try to avoid close contact with people having respiratory illness. If one gets sick with influenza, one must stay at home, away from work or

school and limit contact with others to keep from infecting them.

PREVENTIVE TREATMENT• VACCINATION:

– A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.

– Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).

• NASOVAC TM: (Serum Institute of India Ltd)

– Formulation: Inhalation

– About the vaccine: Live attenuated strains of weakened forms of H1N1 virus– Prescribing information: The single dose vaccine, fitted at the top of a syringe, is

just to be sniffed once in each nostril, making it a painless prevention. It is a single dose, does not need a booster dose. Age: Above 3 yrs

• VAXIFLU- S (Zydus Cadilla)

– Formulation: IM Injection

– Prescribing information: Vaxiflu-S comes as a single dose containing hemaglutining antigen of A/California/7/2009H1N1. Given as IM injection. Used in 18yrs and above only.

DRUG TREATMENT• The Government has in the designated hospitals stored medicines if

required. It is strongly advisable not to take medicines of your own, as it will lower your immunity. The different ways of its treatment are as follows:

• Neuraminidase inhibitor antiviral medications – These medications target the early phase of the infection. However, this

strain is resistant to adamantanes, such as amantadine and rimantadine– Example: Oseltamivir, Zanamivir

• Oseltamivir (Tami flu): Therapy Area influenza; influenza A Drug Class Antiviral Product Type Drug

• Possible herbal therapy – There are a lot of herbs have evaluated for the beneficial effects in swine

flu– Example: Elderberry, Japanese wasabi leaves, Tulsi etc.

CONTAINMENT

Figure Stage-wise evolution of a pandemic

ROLE OF PHARMACIST IN PREVENTION & TREATMENT OF H1N1 INFECTION

• Pharmacist can play a major role in prevention and treatment of H1N1 infection. In order to prevent spreading of virus across the world, the first basic steps need to be taken is to prevent the source of infection that is swine, by prevent transfer of infection among them, than give proper treatment to those swine which already suffer from infection and proper disposal of swine flu affected body which were die due to swine infection. The best method for it is incineration. Following steps one can take in order to prevent transmission of influenza among swine.

1) Prevention of pig to human transmission:

2) Prevention of human to human transmission : – Ways of human to human transmision

– Ways of prevention for human to human transmission

CONCLUSION• Influenza H1N1 virus is spreading rapidly through sustained human-

to-human transmission in multiple countries.

• Infected person may be able to infect others beginning one day before symptoms develop and up to seven or more days after becoming sick.

• However, with efficient human to human transmission established and more than 48 countries involved, so a series of actions need to be put in place to contain the outbreak.

• Few of the antiviral drugs are available in the market for treating this wide spread infecting disease but due to their immense side effects, scientists are now, turn their attention towards herbal therapy.

• So through this article we tried to collect the brief information about this particular disease.

• We can play main role in the prevention of the transmission of this disease by following the main factors enlisted in the review article.