Monday, May 13, 2019

Health-Influennza

Universal Immunization Programme
• Universal Immunization Programme was launched in 1985.
• The program now consists of vaccination for 12 diseases:
1) Tuberculosis
2) Diphtheria
3) Pertussis (whooping cough)
4) Tetanus
5) Poliomyelitis
6) Measles
7) Hepatitis b
8) Diarrhoea
9) Japanese encephalitis
10) Rubella
11) Pneumonia( Heamophilus Influenza Type B)
12) Pneumococcal diseases (Pneumococcal Pneumonia and Meningitis)
• The Indradhanush mission, launched in 2014, is to fast track the universal immunization programme.
• The mission aims at increasing the immunisation coverage to 90% by 2018.
5.2 Polio
• Polio is a highly infectious disease caused by a virus.
• It invades the nervous system and can cause total paralysis (Acute flaccid Paralysis) in a matter of hours.
• The virus is transmitted by person-to-person spread mainly through the faecal-oral route or, less frequently, by a common vehicle (for example, contaminated water or food) and multiplies in the intestine.
• Initial symptoms are fever, fatigue, headache, vomiting, stiffness of the neck and pain in the limbs.
• There is no cure for polio, it can only be prevented.
• Polio mainly affects children under 5 years of age. Polio vaccine, given multiple times, can protect a child for life.
• There are 3 strains of wild poliovirus (type 1, type 2, and type 3).
• P2 was eradicated globally in 1999. The last case due to type-2 wild poliovirus globally was reported from
Aligarh in India in 1999.
• India attained a polio-free status in 2014 after successfully eliminating the wild P1 and P3 strains.
• India eliminated the type-2 strain in 2016, and the type-2 containing poliovirus vaccine (ToPV) was phased out in April 2016.
• Thus, Children born after April 2016 in India have no immunity to type-2 polio virus.
• Recently, Traces of polio type-2 virus were found in some batches of oral polio vaccine (OPV) manufactured by a Ghaziabad-based pharmaceutical company.
• No case of type 3 has been found since the last reported case in Nigeria in November 2012.
• Today, only 3 countries in the world have never stopped transmission of polio (Pakistan, Afghanistan and Nigeria).
• The vaccine used by the World Health Organisation (WHO) in the global eradication effort is a trivalent preparation comprising all three serotypes.
5.3 Pulse Polio Campaign
• It is an immunisation campaign established by the GoI to eliminate poliomyelitis in India by vaccinating (Oral Polio Vaccine) all children under the age of five years.
• Vellore (Tamil Nadu) was the first Indian town to become polio-free through the pulse strategy, and rest of India adopted the strategy in 1995.
• Oral Polio Vaccine (OPV) contains weakened but live polio virus, which can cause paralytic polio.
• OPV reduced the outbreak caused by wild polio virus by 99.9% since 1988.
• The vaccine-virus is excreted by immunized children, it can move from one person to another.

Elimination and Eradication
• Elimination means stopping the transmission of a disease in a specific geographic area or country, but not worldwide.
• Disease eradication is the permanent reduction of a disease to zero cases through deliberate measures such as vaccines.
• Once a disease has been eradicated, intervention measures are no longer needed.

On the one hand, a vaccinated person protects unvaccinated people she comes in contact with by spreading immunity through faeces.
• But on the other, such circulation allows the virus to stick around and mutate to a more virulent form, raising the spectre of vaccine-derived poliovirus (VDPV).
• This makes OPV a double-edged sword.
• Vaccine Derived Polio Virus (VDPV), like imported wild polio, can cause outbreaks in under-immunised population.
• According to The Lancet, vaccination (using OPV) has become the main source of polio paralysis in the world.
• It is for this reason that the eradication of polio worldwide requires OPV to be stopped and replaced with the Inactivated Polio Vaccine (IPV).
• It consists of killed poliovirus strains of all three poliovirus types and it produces antibodies in the blood to all three types of poliovirus.
• In the event of infection, these antibodies prevent the spread of the virus to the central nervous system and protect against paralysis.
• It is administered alone or in combination with other vaccines including the OPV (oral polio vaccine).
• IPV does not cause VDPV but protects children equally well against polio.
• The two remaining viruses that are circulating in Pakistan and Afghanistan are WPV-1 and WPV-3.
• Once we stop these two viruses in their tracks, OPV will be phased out and replaced globally with IPV.
5.4 Tuberculosis
• TB is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs.
• It is curable and preventable.
• It is spread from person to person through the air.
• About 1/4th of the world's population has latent TB, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.
• It mostly affects adults in their most productive years. However, all age groups are at risk.
• People who are infected with HIV are 20 to 30 times more likely to develop active TB
• 8 countries accounted for two thirds of the new TB cases: India,China,Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh and South Africa.
• Multidrug-resistant tuberculosis (MDR-TB) is a form of TB caused by bacteria that do not respond to the most powerful first-line anti-TB drugs (isoniazid and rifampicin).
• MDR-TB is treatable and curable by using second-line drugs (bedquiline and delamanid).
• According to the WHO guidelines, all injectables are to be replaced with a fully oral regimen with Bedaquiline to treat MDR-TB patients.
• South Africa was the first country to scale up access to bedaquiline. It would replace the injectablesfor treating all MDR-TB patients.
• Extensively drug-resistant TB (XDR-TB) is a more serious form of MDR-TB caused by bacteria that do not respond to the most effective second-line anti-TB drugs, often leaving patients without any further treatment options.
• Worldwide, only 55% of MDR-TB patients are currently successfully treated.
5.5 Latent Tuberculosis Infection
• Persons with LTBI are those who harbor the TB-causing bacteria within, where it can lie dormant.
• In other words, it is a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens without evidence of clinically manifested active TB.
• The WHO lays emphasis on a specific strategy to tackle latent TB but only in high- and upper middle-income countries with a low incidence of the disease.

According to a WHO report, approximately 10% of people with LTBI will develop TB, with the majority of them getting it within the first five years of infection.
• LTBI can often be tackled by maintaining good health and observing coughing and sneezing etiquette.
5.6 Diphtheria
• Diphtheria is a highly contagious respiratory disease caused by the bacterium Corynebacterium diphtheria.
• It primarily infects the throat and upper airways and produces a toxin affecting other organs.
• The toxin causes a membrane of dead tissue to build up over the throat and tonsils, making breathing and swallowing difficult.
• The disease is spread through direct physical contact or from breathing in the coughs or sneezes of infected individuals.
• It can be fatal if left untreated but has become increasingly rare in recent decades due to high rates of vaccination.
• Government hospitals in Delhi has reported a dozen diphtheria deaths in children over two weeks.
5.7 Japanese Encephalitis
• It is a mosquito-borne viral infection of the brain.
• Japanese encephalitis virus (JEV) is a flavivirus related to dengue, yellow fever and West Nile viruses, and is spread by mosquitoes.
• There is no cure for the disease. Treatment is focused on relieving severe clinical signs and supporting the patient to overcome the infection.
• JEV is transmitted to humans through bites from infected mosquitoes of the Culex species.
• The virus exists in a transmission cycle between mosquitoes, pigs and/or water birds (enzootic cycle).
• Safe and effective JE vaccines are available to prevent disease and it is one of the vaccines given under Universal Immunisation Programme of India.
• India has confirmed recent cases of JE in Assam, Kerala, Madhya Pradesh, and Maharashtra.
5.8 Lymphatic filariasis
• Lymphatic filariasis is commonly known as elephantiasis.
• It is caused by infection with parasites classified as nematodes (roundworms), which are transmitted to humans through mosquitoes.
• Mosquitoes are infected with microfilariae by ingesting blood when biting an infected host.
• Infection is usually acquired in childhood causing hidden damage to the lymphatic system.
• Its visible manifestations may occur later in life, causing temporary or permanent disability.
5.9 Leprosy
• Leprosy, also known as Hansen’s disease, is a bacterial disease.
• It affects skin and nerves which can lead to physical deformity and disability if left untreated.
• It is not hereditary and completely curable, as opposite to general public views on leprosy.
• It is only mildly infectious (i.e) more than 85% of cases are non-infectious and over 95% of the population has a natural immunity to the disease.
• Leprosy colonies in the country still faces stigma and government’s attention towards it is also going down.
• This is mainly because of WHO declaration of the elimination of leprosy as a public-health concern in India in 2005.
• This has diluted the international funding and reduced attention and made life difficult for the people living in the colonies.

Hepatitis C
• WHO has listed viral hepatitis as a major public health problem throughout the world and particularly in India
• Hepatitis is an inflammation of the liver caused by blood borne Hepatitis Virus.
• There are 5 main hepatitis viruses, referred to as types A, B, C, D and E.
• It has the same mode of transmission as HIV, spreading through blood, injecting drugs, blood transfusion and sexual activity, and from mother to child during pregnancy.
• Hepatitis A is closely associated with unsafe water or food, inadequate sanitation and poor personal hygiene.
• Unlike hepatitis B and C, hepatitis A infection does not cause chronic liver disease and is rarely fatal.
• Hepatitis C virus (HCV) is mostly transmitted through exposure to infective blood and it can cause both acute and chronic hepatitis.
• Acute HCV infection is usually asymptomatic (persons do not exhibit symptoms)and is only very rarely associated with life-threatening disease.
• HCV can also be transmitted sexually and can be passed from an infected mother to her baby, but it is not spread through breast milk, food, water or by casual contact.
• Hepatitis A & E virus are responsible for sporadic infections and the epidemics of acute viral hepatitis.
• Hepatitis B & C virus predominantly spread through the parental route and are notorious for causing chronic hepatitis.
• According to WHO Hepatitis is preventable and treatable but remains an acute public health challenge globally and in the Southeast Asia region.
• Currently, there is no vaccine for hepatitis C; except Hepatitis C, all other hepatitis viruses have safe and effective vaccination to prevent them.
• Note: Hepatitis B is included in India’s Universal Immunisation Programme (UIP).
• HCV is an important public health issue in India.
• In Uttar Pradesh, Bijnor district, Pahuli village has emerged as a hotspot of hepatitis C infection.
• Union Health Ministry’s National Programme for Control of Viral Hepatitis for 2018-19, for the next three years, hopes to screen the vulnerable population and provide free treatment where needed.
• The National Hepatitis Policy will translate into better surveillance and detection of water and blood-borne hepatitis viral infections in various regions.
5.11 Typhoid
• Typhoid is an infection caused by the bacterium Salmonella typhimurium (S. typhi).
• The bacterium lives in the intestines and bloodstream of humans.
• S. typhi enters through the mouth and spends 1 to 3 weeks in the intestine. After this, it makes its way through the intestinal wall and into the bloodstream and finally spreads into other tissues and organs.
• It spreads between individuals by direct contact with the feces of an infected person.
• It infects humans due to contaminated food and beverages.
• Transmission is always human to human as no animal carry this disease.
• Increasing resistance to antibiotic treatment is increasingly making it easier for typhoid to spread.
• Overcrowded populations in cities and inadequate and/or flooded water and sanitation systems add to the cause
5.12 Scrub Typhus
• It is an acute illness in humans caused by a bacterium.
• It is transmitted by the bite of infected mite larva present in the soil.
• Gorakhpur in U.P is treated as a hub of Acute Encephalitis Syndrome (AES).

Number of patients affected by AES admitted in the Hospital has increased during Monsoon period.
• To find out the reason behind this, researchers has identified the role of scrub typhus.
• Almost, 65% of the AES patients got infected by Scrub Typhus.
• This finding is important, given that scrub typhus can be treated easily if detected early.
• The increase in infestation of rodents by mites during August-October explains why scrub typhus incidence peaks during monsoon.

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