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Other Viral Diseases
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02 Sep

Other Viral Diseases

Health and DiseasesBy abhishek levelupias0 Comments
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1) MEASLES

  • Measles is a highly contagious infectious disease caused by measles virus. It spreads through air when an infected person coughs or sneezes. It is an acute respiratory illness. Infection is characterized by a prodrome of fever (as high as 105 degree F) and malaise, cough, coryza, and conjunctivitis – the three “C”s, followed by maculopapular rash. The rash spreads from the head to the trunk to the lower extremities.
    • It can severely sicken young children, but is normally kept under check due to large-scale vaccination.
  • About the Virus:
    • It is a single stranded, enveloped RNA virus with 1 serotype. It is classified as a member of the genus Morbillivirus in the Paramyxoviridae family.
    • Humans are the only natural host of the measles virus.
  • Detection:
    • RT-PCR
    • Anti-body test
  • Vaccinations:
    • Measles can be prevented with Measles-containing vaccine, which is primarily administered as the combination of measles-mumps-rubella (MMR) vaccine.
    • It can be used for children aged 12 months through 12 years. One dose of MMR vaccine is approximately 93% effective and two doses are approximately 97% effective.
  • Rise of Cases in 2022:
    • This was primarily due to disruption of routine vaccination during 2020 and 2021 due to focus on COVID-19 and lockdown
  • WHO Report and India’s Response (Nov 2023)
    • A new report from the WHO and US Centre for Disease Control and Prevention (CDC) said measles cases in 2022 have increased by 18%, and deaths by 43% globally, compared to 2021.
      • Cases: 9 Million & Deaths – 1,36,000
    • The report also said that globally 22 million children and in India 1.1 million infants didn’t get the first dose of vaccine.
    • India has differed from this report:
      • MoH&FW says that just over 21,000 Indian children didn’t get the shot.

2) RUBELLA

  • Rubella is a contagious viral disease caused by a virus. Most people who get Rubella usually have a mild illness, with symptoms that can include a low grade fever, sore-throat, and a rash that starts on the face and spreads to the rest of the body. It can cause a miscarriage or serious birth defects in a developing baby if a woman is infected while she is pregnant.
  • The best protection against rubella is MMR (Measles,Mumps,Rubella) vaccine.

3) HUMAN IMMUNODEFICIENCY VIRUS (HIV) AND AIDS (ACQUIRED IMMUNODEFICIENCY SYNDROME)

  • Why in news?
    • Hopes dashed as last HIV vaccine trial in Africa for his decade ends in failure (Dec 2023: Source – DTE)
  • Introduction:
    • About virus:
      • HIV are two species of Lentivirus (genus) of Retroviridae family. The virus first emerged in 1920 in Kinshasa (then Leopoldville), Belgian Congo.
    • The Human Immunodeficiency Virus (HIV) targets the immune system and weakens people’s surveillance and defence systems against infections and some types of cancers.
      • As the virus destroys and impairs the function of the immune cells, infected individuals gradually become immunodeficient. Immune function is typically measured by CD4 cell count.
      • The most advanced for of HIV infection is acquired immunodeficiency syndrome (AIDS), which can take from 2 to 15 years to develop depending on individual. It is defined by developments of certain cancers, infections, or other severe chemical manifestations.
      • Note: CD4 cells are a type of white blood cells that play a major role in protecting your body from infection. They send a signal to activate your body’s immune response when they detect “intruders” like the viruses or bacteria.
  • Transmission
    • Exchange of a variety of body fluids – blood, breast milk, semen and vaginal secretion
    • Note: Individual can’t be infected through ordinary day to day contact such as kissing, hugging, shaking hands, sharing food or water etc.
  • Behaviours or conditions which can put individual on risk:
    • Unprotected sex (including anal)
    • Having other STDs like syphilis, herpes, chlamydia etc.
    • Use of contaminated needles, syringes etc. while injecting medicines or drugs.
    • Unsafe blood transfusion and medical procedures
    • Infected mother to unborn child.
  • Diagnosis
    • Three types of tests:
      • Antibody test: By detecting presence or absence of antibodies to HIV in blood; most commonly used test.
        • When someone is infected with HIV, the immune system produce proteins called anti-bodies, and they are directed against the unique proteins of HIV. Though, these antibodies are not able to eliminate the virus, but they serve as a marker to show that someone is infected with HIV.
      • RNA (viral load) test (RT-PCR)
      • A Combination test
        • It detects both antibodies and viral protein called p24 (antibody-antigen test, or HIV Ab-Ag test).
          • P24 forms part of the core of the virus (an antigen of the virus).
  • Prevention
    • Avoid risk behaviours (i.e. use condoms, test and counsel for HIV and STIs, Voluntary medical male circumcision, using only sterile injecting instruments)
    • Antiretroviral (ART) use for prevention.
      • ART as Prevention – If an HIV positive person adheres to an effective ART regimen, the risk of transmitting the virus to their uninfected sexual partner can be reduced by 96%.
      • Pre-exposure prophylaxis (PrEP) for HIV negative partner: Oral PrEP of HIV is the daily use of ARV drugs by HIV uninfected people to block the acquisition of HIV.
      • Post Exposure prophylaxis for HIV (PEP): PEP is the use of ARV drugs within 72 hours of exposure to HIV in order to prevent infection. PEP includes counselling, first aid care, HIV testing, and administering of a 28-day course of ARV drugs with follow up care.
    • Drug releasing Vaginal Ring Cap: To prevent HIV-AIDS in Women
      • The ring is made of flexible silicon matrix polymer. The woman inserts it into the vagina, where it, over the course of a month, releases the antiretroviral drug dapivirine. It has to be changed after 28 days.

 

A) STEM CELL THERAPY TO TREAT HIV HAVE SHOWN SUCCESS:

    • In 2022, a US patient was reported cured of HIV after stem cell transplant. By July 2023, six persons had been cured by this method.
    • In the first five cases, the treatment teams specifically looked for donors with CCR5 delta 32 mutation. It is associated with lower risk of HIV.
      • People who inherit CCR5 delta 32 mutation from both parents don’t from the receptors which are used by HIV virus to enter the cells. Those who inherit the mutation from one of the parents have fewer receptors and are less likely to get infection.
      • Only 1% of the people on earth carry 2 copies of CCR5-delta 32 mutation.
    • Why can’t stem cell transplant become routine treatment for HIV?
      • Finding matching donor for all 40 million patients would be impossible.
      • The CCR5 delta 32 mutation occurs mostly in Caucasians whereas most of the cases are in the African continent.
      • Further, stem cell transplant is a complex process and comes with its own risks.
    • SDG Goal 3.3: To achieve the end of AIDS by 2030 i.e. zero new infection by 2030.

 

B) GLOBAL SITUATION OF HIV:

    • Successes Achieved in HIV Response:
      • As per UNAIDS, in 2022, 39 million people globally were living with HIV, of whom 29.8 million were accessing ART.
        • Coverage of ART has becomes 4 times of the number in 2010.
      • New Cases: Around 1.3 million people got newly infected with HIV in 2022 – which is 59% lower from the peak in 1995.
      • It is possible to end AIDS by 2030: UNAIDS
  • WHO response
    • WHO is cosponsor of the United Nation Program on Aids (UNAIDS). Within UNAIDS, WHO leads activities on HIV treatment and care, HIV and tuberculosis co-infection, and jointly coordinate with UNICEF the work on the elimination of mother to child transmission of HIV.

 

C) VACCINATION EFFORTS:

    • Hopes Dashed as last HIV vaccine trial in Africa for this decade ends in failure (Dec 2023)
      • The study, known as PrEPVacc, was led by African researchers with support from European Scientists.
        • They were testing two different vaccine regimes on about 1500 volunteers in Uganda, Tanzania, and South Africa.
      • After, multiple other high-profile trails failed in the past, PrEPVacc researchers were quite optimistic and had described the latest study as the final trial of the decade.

 

D) HIV SITUATION IN INDIA

    • More than 2 million people in India live with HIV.
      • HIV Epidemic has an overall decreasing trend in the country with estimated annual new HIV infections declining by 37% between 2010 and 2019.
    • Success in controlling AIDS
      • 2015 HIV estimates results reaffirm the country’s success story in responding to HIV/AIDS epidemic. India has successfully achieved 6th Millennium Development Goal (MDG6) of halting and reversing the HIV epidemic.
    • Emergence of three north Eastern States as new HIV Hotspots: Mizoram (1.19%), Nagaland (0.82%), Meghalaya (0.73%), Tripura (0.56%) and Manipur (0.47%)
      • Reasons: Injecting Drug Users and Unsafe Sexual Practices.
  • Steps taken by government of India in recent times to Reduce HIV transmission
    • National Aids Control Program was launched in 1992 and its four phases have been completed so far. It is a central sector scheme.
      • It has been extended for five years (1st April 2021 to 31st March 2026)
      • It is a comprehensive program for prevention and control of HIV/AIDS in India.
      • Under this, ART Centres run by National AIDS Control Office (NACO) provide lifetime free medicines, diagnostic kits and other essentials for those in need.
    • National Aids Control Organization (NACO), under MoH&FW, provides leadership to HIV/AIDS program.
    • HIV & AIDS Prevention and Control Act 2017 provides a legal framework for protecting the rights of HIV positive people.
    • Implementation of 90:90:90 strategy adopted by UNAIDS
    • Other steps include – Multimedia campaigns; Red ribbon clubs in colleges; training and sensitization program for SHGs; etc;

4) POLIO

  • Basics:
    • Polio is a highly infectious disease caused by a virus. It invades the nervous system and can cause total paralysis in a matter of hours.
    • Transmission: The virus is transmitted by person to person and spread mainly through faecal-oral routes, or less frequently by, a common vehicle (e.g., contaminated water or food) and multiplies in the intestine.
    • Symptoms: Initial symptoms are fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs.
    • Affect: 1 in 200 infections leads to irreversible paralysis (usually in legs). Among those paralyzed, 5% to 10% die when their breathing muscles become immobilized.
    • People most at risk
      • Polio mainly affects children under five years of age
    • Prevention and Cure
      • There is no cure
      • It can only be prevented. Polio vaccine given multiple times can protect a child for life.
  • Three Different strains of Polio Virus
    • 3 strains of poliovirus (type 1, type 2, and type 3).
    • Wild polio virus type 2 was eradicated in 1999.
    • Wild Polio virus type 3 was eradicated in 2019.
      • WPV3 is the second strain of the polio virus to be wiped out, following the certification of the eradication of WPV2 in 2015.
      • The last case of WPV3 was detected in Northern Nigeria in 2012.

 

A) TWO TYPES OF VACCINES: OPV AND IPV

    • Oral Polio Vaccine (OPV) is taken orally as drops. It has served as the main preventive measure against polio and is easily administered not requiring very trained health workers. Further, the cost per dose of OPV is much less than IPV. It also leads to passive immunization.
      • Other Advantages
        • Passive immunization
      • Limitations
        • Virus may mutate and turn virulent Or;
        • Virus may multiply in intestine and spread through excreta and over the period mutate to become virulent.
    • Inactivated Polio Vaccine (IPV) is given through an injection by a trained health worker.
      • It is not a “live” vaccine (i.e. it is inactivated) and thus carries no risk of vaccine associated paralysis.
      • In countriesstill usingOPV,IPV hasn’t replaced OPVbut isused tostrengthen a child’simmune system and protect them from polio.

 

B) ISSUE OF VACCINE DERIVED POLIO VIRUS

    • How vaccines may lead to infection
      • Oral Polio Vaccine (OPV) contains an attenuated vaccine-virus. This weak form of the virus is used to activate an immune response in the body, which protects the child when challenged by WPV.
      • But when child is immunized with OPV, the virus replicates in the intestine and during this time the virus is excreted.
    • WHO recommendations
      • Use of OPV must eventually be stopped (starting with OPV containing Type-2 poliovirus) worldwide and at least one dose of IPV must be introduced, to protect against Type-2 Polio virus and to boost population immunity.
    • Why??
      • Since, wild Polio virus of type 2 was eradicated in 1999, the risk of paralytic disease due to OPV type 2 now outweighs its benefits.
      • A single dose of IPV before OPV protects against VAPP (Vaccine Associated Paralytic Poliomyelitis).
  • IPV is very safe vaccines in humans, whether used alone or in combination vaccines.
    • No serious adverse events have been reported, only minor side effects.
    • It doesn’t cause VAPP or cVDPV
  • Situation in India
    • India was declared Polio free in 2014, 3 years after the last case of Polio in 2011. But we still see cases of vaccine derived Polio.
    • Further, there have been cases of Non-Polio Acute Flaccid Paralysis (NPAFP) which are associated with OPV.
      • NPFAP is defined as a sudden onset of paralysis or weakness in any part of the body of a child less than 15 years of age.
      • All AFP cases in last six years (2012-2018) have been due to non-polio causes. But, NPAFP has shown high correlation with number of pulse polio round conducted.
      • According to a recent paper (Aug 2018) by NCBI, since India has been polio free for six years, we can reduce the cases of NPAFP by further reducing polio rounds.

5) EBOLA VIRUS DISEASE (EVD)

  • Introduction:
    • The Ebola virus causes an acute, serious illness which is often fatal if untreated.
    • Ebola Virus Disease first appeared in 1976 in two simultaneous outbreaks, one in Nzara, Sudan, and the other in Yambuku, Democratic Republic of Congo. The later occurred in a village near the Ebola River, from which the disease takes its name.
    • 2014-2016 outbreak: This outbreak in Wet Africa was the largest and most complex Ebola outbreak since the discovery of virus. It had mostly impacted Guinea, Sierra Leone and Liberia.
  • Virus: The virus family Filoviridae includes the Ebolavirus genus. This Ebolavirus Genus has 5 identified species so far: Zaire, Bundibugyo, Sudan, Reston and Tai Forest. The first three Zaire Ebola virus, Bundibugyo Ebolavirus, and Sudan Ebolavirus have been associated with large outbreaks in Africa. 2014 outbreak has been caused by Zaire Ebolavirus.
  • Transmission
    • Introduction in Human: It is believed that fruit bats of the Pteropodidae family are natural Ebola virus hosts.
    • Human to Human: Via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other fluids of infected people, and with surface and materials (e.g., bedding clothing) contaminated with these fluids.
  • Diagnosis
    • Difficult to distinguish EVD from other infectious diseases such as malaria, Typhoid fever and meningitis.
    • Confirmation tests: Electron Microscopy, ELISA, RT-PCR etc.
  • Treatment and Vaccine
    • Supportive care rehydration with oral or intravenous fluids – and treatment of specific symptoms, improves survival.
    • There is as yet no proven treatment available for EVD
    • However, a range of potential treatments including blood products, immune therapies and drug therapies are currently being evaluated
    • Vaccines has been developed and is being used in DRC.
      • Vaccine rVSV-ZEBOV (tradename “Ervebo”) was approved by US FDA in Dec 2019.
    • Monocolonal Anti-Bodies have also been found effective in treatment: WHO
  • Prevention and Control
    • Good outbreakcontrol relies on applyinga package of interventions, namely case management, surveillance and contact tracing, a good laboratory service, safe burials and social mobilization.

6) RABIES

  • About Rabies:
    • It is a vaccine preventable viral disease which occur in more than 150 countries in the world.
      • Dogs are the main source of human rabies deaths, contributing to 99% of all rabies transmission to humans.
        • It is spread when infected animal bites or scratches a human or other animal. Saliva from an infected animal can also transmit rabies if the Saliva comes into contact with the eyes, mouth, or nose.
      • Interrupting transmission is feasible through vaccination of dogs and prevention of dog bites.
      • Immediate, thorough wound washing with soap and water after contact with a suspected rabid animal is crucial and can save lives.
      • Rabies is virtually 100% fatal once the clinical symptoms appear. And it is also 100% vaccine preventable.
    • WHO is also leading a collective “United Against Rabies”to drive progress towards “Zero Human Deaths from dog mediated rabies by 2030”.
    • World Rabies Day is held on 28th September.
    • About the Virus:
      • It is caused by lyssaviruses, including the rabies virus and Australian bat lyssavirus.
      • The virus infects the central nervous system. If a person doesn’t receive the appropriate medical care after potential rabies exposure, the virus can cause disease in the brain, ultimately resulting in death.
  • Situation of Rabies in India
    • As per WHO India is endemic to rabies and suffers approx. 36% of the world’s human rabies deaths, transmitted by dogs.
  • Key Highlights about Efforts in India:
    • The ministers have urged all the States to make Rabies a notifiable Disease.
    • They launched ‘Joint Inter-Ministerial Declaration Support Statement’ for elimination of Dog Mediated Rabies from India by 2030 through One Health Approach.
    • IEC campaign should be launched to help people understand the difference between vaccine and medicines for rabies.
    • On the occasion of the World Rabies Day (28thSep), the MoH&FW and the Minister of Fisheries, Animal Husbandry and Dairying unveiled the National Action Plan for Dog mediated Rabies Elimination by 2030 (NAPRE).
      • Its approach for elimination of rabies is based on recommendations of several international agencies WHO and the Global Alliance of Rabies Control (GARC).
      • It was prepared on the basis of 5 major pillars– political will, intersectoral planning, sustained funding, community planning, coordination & review, and operational research.

7) HUMAN PAPILLOMA VIRUS (HPV)

  • What is HPV?
    • HPV is a group of 150 related viruses.
    • Cancer Causing: Some HPV can lead to cancer, especially cervical cancer.
    • There are more than 40 HPV that can infect genital areas of males and females.
  • How do people get HPV?
    • Transmitted through intimate skin to skin contact which can happen during vaginal, anal or oral sex with someone who has virus. Most common sexually transmitted disease. HPV is so common that nearly all sexually active men and women get it at some point in their lives. HPV can be passed even if the infected person has no signs or symptoms.
  • Does HPV Cause Health Problem?
    • In most cases, HPV goes away on its own and doesn’t cause any health problems. But when HPV doesn’t go away, it can cause health problems like genital warts and cancer.
      • Genital Warts usually appear as a small bump or group of bumps in the genital area.
      • Cancer: HPV can cause cervical cancer and other cancers including cancer of vulva, vagina, penis and anus. It can also cause cancer in the back of the throat, including the base of tongue and tonsils. The types of viruses that cause genital warts are not the same as types of HPV that cause cancers.
  • How can I avoid HPV and the health problems it can cause?
    • Get Vaccinated:
    • Get screened for cervical cancer: Routine scanning for women aged between 21 to 65 years old can prevent cervical cancer.
    • For Sexually Active people
      • Use latex condoms the right way every time you use them. This can lower your chances of getting HPV. But HPV can infect areas that are not covered by condoms – so condoms may not give full protection against getting HPV
      • Be in mutually monogamous relationship i.e., have sex only with someone who only has sex with you.
  • Can I be treated for HPV or health problems caused by HPV?
    • No treatment for virus itself, but there are treatments for health problems associated

8) CERVICAL CANCER

  • Why in news?
    • Nine out of 10 women who die of cervical cancer live in low and middle-income countries, according to WHO.
  • Details:
    • The low- and middle-income countries have low rate of vaccination against the HPV, which causes the cancer.
      • Most HPV vaccination consignments go to wealthier nations, driving a gap in access similar to the inequitable distribution of vaccines against the COVID-19.
      • Vaccines haven’t been introduced in 80 countries and these countries record 2/3rd the incidences of cervical cancer.
      • Globally, just 13% of girls between nine and fourteen years were vaccinated against HPV in 2020. This was a reduction from 15% girls in 2019.
  • 4th HPV Vaccine:
    • In Oct 2021, WHO has given approval to Ceolin, manufactured by Xiamen Innovax Biotech Co Ltd to bridge the gap

9) DENGUE

  • Dengue fever, also known as break bone fever, is a mosquito borne tropical disease caused by the dengue virus.
    • Dengue Virus (DENV) in one of the five serotypes is the cause of Dengue fever. It is a mosquito borne single positive stranded RNA virus of the family Flaviviridae; genus Flavivirus.
    • Dengue can affect anyone but tends to be more severe in people with compromised immune systems.
    • Dengue hemorrhagic Fever (DHF) is a specific syndrome that tends to affect children under 10 years of age. It causes abdominal pain, hemorrhage (bleeding), and circulatory collapse (shock).
  • Possible to get dengue multiple times
  • Symptoms
    • Severe joint and muscle pain, swollen lymph nodes, headache, fever, exhaustion, and rash. The presence of fever, rash, and headache (the dengue “triad“) is characteristics of dengue fever.
  • Geographical Regions
    • Prevalent throughout the tropics and subtropics.
  • Transmission
    • The virus is contracted from the bite of a striped Aedes aegypti mosquito that has previously bitten an infected person. The virus is not contagious and cannot spread from person to person directly. There must be person to mosquito to another person pathway.
  • Treatment
    • Symptomatic treatment)
  • Prevention
  • Vaccine:
    • Since there are around 5 serotypes of dengue virus known, vaccine making is difficult. It’s because different vaccine is needed against each serotype.
    • A vaccine against dengue, DENGVAXIA, from Sanofi Pasteur is approved in several countries and shows efficacies ranging from 42% to 78% against four serotypes of the virus.
    • In India, Zydus Cadilla has been developing a DNA vaccine against dengue

10) ZIKA FEVER / ZIKA DISEASE

  • About Zika Virus
    • Zika virus (ZIKV) is a member of the Flaviviridae virus family and the Flavivirus genus, transmitted by daytime active Aedes mosquitoes, such as A. aegypti, A. Africanus, A. furcifer etc. Virus can also get transferred during sexual contacts, across the placenta (affecting unborn child). A mother already infected with Zika virus near the time of delivery can pass on virus to the newborn around the time of birth but this is rare.
    • Zika virus is related to dengue, yellow fever, Japanese Encephalitis, and West Nile virus. The illness it causes is similar to mild form of dengue fever, is treated by rest, and cannot yet be prevented by drugs or vaccine.
  • Earliest discovery
    • Virus was first isolated in 1947 from a rhesus macaque monkey that had been placed in a cage in the Zika Forest of Uganda, near Lake Victoria, by the scientists of yellow fever research institute.
  • Spread among Humans:
    • For the first 60 years after detection, only 14 human cases has been reported from Tropical Africa and Asia (including India in 1952-53).
    • The first ever outbreak (185 cases) of Zika virus was reported in 2007 in the island of Yap (a federated state in Micronesia) in the Pacific.
    • In 2015 to Mexico, Central America, the Caribbean, and South Africa, where the Zika outbreak has reached pandemic levels.
      • The outbreak was associated with higher incidences of microcephaly as well as GB syndrome.
  • Symptoms and treatment
    • Common symptoms include mild headaches, maculopapular rash, fever, joint pains etc.
      • Thus far, Zika fever has been a relatively mild disease of limited scope, with only one in five persons developing symptoms, with no fatalities, but is true potential as a viral agent is unknown.
    • As of 2022, no WHO approved vaccine or preventing drug is available. Symptoms can be treated, with rest, fluids, and paracetamol, while aspirin and other non-steroidal anti-inflammatory drugs should be used only when dengue has been ruled out to reduce the risk of bleeding.
  • Zika’s link with Microcephaly and GB Syndrome
    • Microcephaly is a condition where a baby has a head size much smaller than other babies of the same age and sex. According to WHO this condition may be caused in newborn by mother to child Zika virus transmission.
    • GBS (Guillain-Barre Syndrome) is a rapid onset of muscle weakness as a result of damage to the peripheral nervous system. In a French Polynesian epidemic, 73 cases of GBS and other neurological conditions occurred in a population of 270,000, which may be complications of Zika virus.

11) JAPANESE ENCEPHALITIS

  • It’s a viral fever that affects the brain and is considered extremely dangerous for children, and it also has a high “mortality and morbidity rate“.
  • About JE Virus
    • Japanese Encephalitis virus (JEV) is a flavivirus belonging to same genus as dengue, yellow fever and west Nile viruses.
    • It is the main cause of viral encephalitis in many countries of Asia with an estimated 68,000 clinical cases every year.
  • Symptoms of JE includes sudden onset of fever, vomiting, headache, neck stiffness, and seizures.
  • Transmissions
    • The virus is maintained in a cycle between mosquitoes and vertebrate hosts, primary pigs, and wading birds. Humans are incidental ordead-end hosts because they don’t develop high enough concentration of JE virus in their bloodstream to infect feeding mosquitoes.
      • So It is not transmitted from human to human
    • JE virus transmission often occurs in primarily rural agricultural areas, often associated with rice production and flooding irrigation.
    • Transmitted by the bite of Culex tritaeniorhynchus, and Culex vishnui mosquitoes.
  • Management Control and Prevention
    • Vaccination: Safe and effective JE vaccines are available to prevent disease. WHO recommends having strong JE prevention and control system.
      • In the mission Indradhanush – JE vaccination was included in May 2016.
    • Controlling mosquitoes
    • Pigs act as a carrier for the virus – so it is also important to control mosquito population around the pig domestication areas.
    • Animal husbandry department plays an important role here.
  • Treatment
    • No specific treatments have been found to benefit patients with JE, but hospitalization for supportive care and close observation is generally required. Treatment is symptomatic.
      • Rest, fluids, and use of pain relievers and medication to reduce fever may relieve symptoms.

12) ACUTE ENCEPHALITIS SYNDROME (AES)

  • What is AES?
    • AES is a complex syndrome that affects central nervous system, mostly in children and young adults. It starts with fever, then hampers neurological functions causing mental disorientation, seizure, confusion, delirium, coma etc.
    • Causes:
      • It may be caused by virus, bacteria, fungi, and a range of agents. Japanese Encephalitis (JE) is the most common cause of AES in India. But the syndrome is also caused by scrub typhus, dengue, mumps, measles, even Nipah or Zika virus.
  • Relation between Hypoglycemia, children, and AES
    • Some researchers have claimed that there is an increasing correlation between death due to AES and hypoglycaemia. So, AES may affect undernourished children more.
  • Any relation between Litchi and AES
    • More research needs to be done in this aspect.
      • Some toxin/virus/bacteria found in Litchi may be responsible for AES.
      • Unripe fruit contains toxins hypoglycin A and methylenecycloprophyglycine (MCPG) which cause vomiting if ingested in large quantities
    • Note: AES is called “Chamki Bukhar” in Bihar
  • Prevention
    • Preventing Mosquito bite -> keeping surrounding clean to prevent mosquito breeding, wearing full sleeve clothes etc.
    • Drink plenty of water and ensuring proper nutrition flushes out toxins which may be causing AES from the body.
    • Properly washing fruits before consuming them properly.

13) WEST NILE VIRUS

  • About the Virus
    • It is a member of flavivirus genus and Flaviviridae family.
    • It was first isolated in a woman in the West Nile District of Uganda in 1937. It was also identified in birds (including crows) starting 1953 and have also been found to be pathogenic for them (birds).
    • The WNV Is commonly found in Africa, Europe, the Middle east, North America and West Asia.
  • Human Infection is most often the result of bites from infected mosquitoes. Mosquitoes get infected by feeding on infected birds, which circulate the virus in their blood for a few days. It may also be transmitted through contact with other infected animals, their bloods or other tissues. There are also reports about few transmissions through organ transplant, blood transfusion, mother to child etc.
  • Symptoms
    • Asymptomatic (80% of the cases)
    • West Nile Fever (in 20% of infections) -> Fever, headache, tiredness, body aches, nausea, vomiting, skin rash etc.
    • Severe West Nile Disease (also called neuro-invasive disease, west Nile encephalitis or meningitis, or West Nile Poliomyelitis) (less than 1% cases) -> Headache, severe fever, neck stiffness, stupor, coma, tremors, convulsions, and paralysis. People who are above 50 and under immuno-suppressants are under high risk
  • Vector and Animal Hosts
    • WNV is maintained in nature in a mosquito bird mosquito transmission cycle. Mosquitoes of the genus Culex are considered vectors of WNV, in particular Cx. Pipiens.
    • Birds are reservoir hosts in Europe, Africa, Asia and Middle east. But in America, the WNV is highly pathogenic for birds.
    • Horses like humans are dead-end hosts i.e., they get infected but don’t spread the virus.

14) CHIKUNGUNYA

  • Basics about Chikungunya:
    • Virus: Chikungunya is a viral disease caused by an RNA virus that belongs to the aphavirus genus of the Togaviridae family.
    • Vector: The virus is transmitted to humans through the bites of infected female mosquitoes, most commonly, Aedes Aegypti and Aedes Albopictus.
    • Symptoms: Fever, severe joint pain, muscle pain, nausea, fatigue and rash.
    • Shares clinical signs with dengue – They can be misdiagnosed with dengue.
    • Diagnosis: RT-PCR (testing serum or plasma for detection of virus or viral nucleic acid)>
    • Treatment: No cure available, treatment is mostly symptomatic.
    • People at risk: People living in the proximity of mosquito breeding sites.
    • Prevention and Control -> Prevent Mosquitoes and Mosquito bites
    • Less dangerous than dengue -> rarely leads to fatalities. However, it does affect patients severely, leaving them with pain in the joints and swelling.
  • India and Chikungunya:
    • A team from ICMR – National Institute of Virology, Pune have concluded that India has become an endemic reservoir for the virus with persistent global transmission from the country.
  • Vaccine Efforts:
    • BBV87:
      • A multi-country Phase-II/III clinical trial of a vaccine led by the International Vaccine Institute (IVI) in partnership with Bharat Biotech International Ltd (BBIL) began in Costa Rica in Aug 2021.
      • The vaccine is called BBV87. It is an inactivated whole virion vaccine based on a strain derived from an East, Central and South African genotype.
  • Vaccine: No
  • Treatment: Symptomatic
  • Prevention
    • Active animal health surveillance system to detect new cases in birds and horses. (Vaccine for horses)
    • Mosquito control

15) MOSQUITOES ARE EMERGING AS BIG ISSUE

  • Details
    • Aedes Aegypti is native to sub-Saharan Africa, and in its native environment it lives in tree holes and small pools of water and bites non-human primates. These mosquitoes may have first moved to nearby human settlements during droughts when the tree holes dried up. During trans-Atlantic slave trade, the mosquitoes moved out of Africa. The first case of Yellow fever reported outside Africa in Yucatan, Central America in 1648.
    • Aedes albopictus is native to tropical SE Asia, where it was originally a forest species that fed on wild animals. During 1980s it spread to islands in the Indian and Pacific Oceans and then during the 1980s extended its range across temperate regions in Europe, Africa and the Americas.
    • A modelling study published in Nature Communications on May 1, 2020, shows that the world became about 1.5% more suitable per decade for the development of A aegypti during 1950-2000.
    • Another study showed that by 2050, 49% of the World’s population will live in places where A aegypti and A albopictus are present if greenhouse gas emissions continue at the current rates.

 

 

  • Climate change is increasing vector population:
    • Mosquitoes are now able to breed throughout the year.
    • Breeding behaviours of mosquitoes have also changed over the years. Now, they can lay eggs in dirty waters too. There is evidence that Aedes mosquitoes can breed in brackish water too.
    • Artificial lights have increased the feeding period of Aedes mosquitoes.
  • Other factors
    • Aedes aegypti has also developed resistance to common insecticide permethrin.

16) WORLD MOSQUITOE PROGRAM (WMP)

  • Intro
    • WMP is a not-for profit initiative that works to protect the global community from mosquito-borne diseases such as Zika, Dengue, Chikungunya.
    • Pioneered by Australian researchers, the WMP uses safe and natural bacteria called Wolbachia to reduce the ability of mosquitoes to transmit these viruses.
    • WMP was first launched in Australia in 2011 and has expanded rapidly since then.
  • About Wolbachia
    • Wolbachia is a natural bacteria present in upto 60% of insect species, including some mosquitoes. It is one of the most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere.
    • However, they are naturally not found in Aedes aegypti mosquito, the primary species responsible for transmitting human viruses such as Zika, Dengue, Chikungunya, and yellow fever.
    • WMP research has shown that when introduced in Aedes aegypti mosquito, Wolbachia can help reduce the transmission of these virus in people. When introduced into this mosquito’s cells, this parasite competes successfully against other parasites such as the viruses that cause dengue, chikungunya, yellow fever, Zika etc. Thus, it can be used to fight life-threatening diseases.
  • How is it introduced:
    • Aedes mosquitoes, infected with Wolbachia in lab, are released in localities where the disease is prevalent. These lab infected mosquitoes quickly spread the bacterium to native Aedes mosquitoes. Various studies have shown that eventually the dengue cases start to decline in this region.

17) KYASANUR FOREST DISEASE (KFD) / MONKEY FEVER

  • Introduction
    • KFD is caused by KFDV, a member of virus family Flaviviridae. It was first identified in 1957 when it was isolated from a sick monkey in Kyasanur Forest in Karnataka state India.
    • Since then, about 400-500 cases are reported every year from the state.
  • Reservoirs for Virus
    • Hard Ticks (Hemaphysalis spinigera) are the reservoir of the KFD virus and once infected, remain so for life.
    • Monkeys, shrews, and Rodents are common hosts for KFDV after being bitten by an infected tick.
  • KFDV can cause epizootics with high fatality in primates.
  • Transmission
    • Infected tick bite or contact with an infected animal (monkey, shrew etc.). No person-to-person transmission has been known so far.
    • Transmission from other infected animals like goats, cows etc is extremely rare.
  • Symptoms
    • Chills, fever, headache, muscle pain, low platelet, low RBCs and WBCS.
  • Treatment
    • No specific treatment -> hospitalization and support therapy like hydration and usual precautions is important.
  • Vaccine: Yes
    • Used in endemic areas of India.
  • Distribution
    • Historically limited to western and central district of Kar, India. However, some samples have also been found from Tamil Nadu and Kerala.

18) INFLUENZA

 

A) INFLUENZA A VIRUS

There are four types of Influenza viruses: A, B, C, and D. Influenza A and B viruses cause seasonal epidemics of diseases.

Influenza A viruses are the only influenza viruses known to cause flu pandemics (i.e. global epidemics of flu diseases)

Influenza A virus is the only species of the genus Alphainfluenzavirus. It is an RNA virus.

Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N).
 There are 18 hemagglutinin subtypes (H1 - H18) and 11 different neuraminidase subtypes (N1 - N11)

More than 130 influenza A subtype combinations have been identified in nature, primarily from birds, there are potentially many more influenza A subtypes combinations given the propensity of virus "reassortment".

Reassortment is a process by which influenza viruses swap gene segments. It can occur when two influenza viruses infect a host at the same time and swap genetic information.
  • The influenza A virus subtypes that have been confirmed in humans, ordered by the number of known human pandemic deaths, are:
    • H1N1 caused Spanish Flu in 1918 and the 2009 swine flu pandemic.
      • A variant of H1N1 was responsible for the Spanish Flu pandemic that killed some 50 million to 100 million people worldwide in 1918 and 1919.
    • H2N2 caused “Asian Flu” in the late 1950s.
    • H3N2 caused Hongkong Flu” in the late 1960s.

 

B) SWINE FLU

    • Swine Flu is a respiratory disease caused by influenza A viruses that infects respiratory tract of pigs and result in barking cough, decreased appetite, nasal secretion, and restless behavior; the virus can be transmitted to human.
    • The first case of influenza A H1N1 was reported in Mexico in April 2009. Since then, this infection has affected almost all the countries of the world.
      • The Virus
        • Investigators decided to name it H1N1 flu since it was mainly found infecting people and exhibits two main surface antigens, H1 (hemagglutinin type 1) and N1 (neuraminidase type 1). The eight RNA strands from novel H1N1 flu have one strand derived from human flu strains, two from avian (bird) strains, and 5 from swine strains.
        • Most common virus causing swine flu is H1N1 but the flu virus can sometimes also come from other subtypes such as H1N2, H3N1, and H3N2. Since 2017, H3N2 is becoming a dominant strain.
      • Cross Species infections (swine to humans, humans to swine) etc. have mostly remained local and haven’t caused national or worldwide infections in either pig or humans.
      • Transmission to humans:
        • Most common way for humans to catch swine flu is through contact with an infected pig (not through properly cooked pork)
        • Swine flu is transmitted from person to person by inhalation or ingestion of droplets containing virus from people sneezing or coughing.
      • Symptoms
        • Similar to most influenza infections: – fever, cough, nasal secretion, fatigue and headache.
      • Prevention and cure
        • Vaccination is the best way to prevent or reduce the chances of becoming infected with influenza virus.
        • Two antiviral agents, zanamivir (Relenza) and oseltamivir (Tamiflu), have been reported to help prevent or reduce the effects of swine flu if taken within 48 hours of the onset of symptoms.

 

C) AVIAN INFLUENZA: BIRD FLU

    • Intro
      • Bird flu (Avian Influenza) is caused by influenza A viruses.
        • Only viruses of the H5 and H7 subtypes are known to cause the highly pathogenic form of the bird diseases.
          • Most avian influenza virus don’t infect humans; however, some such as A(H5N1) and A(H7N9), have caused serious infections in people.
        • Recently, China reported that H10N3 has also infected humans.
    • There are several subtypes of Avian Influenza
      • AH5N1 is the most common virus causing bird flu, or avian influenza. It is largely restricted to birds,andoftenfatal(high pathogenicity)tothem.it cansometimescrossovertootheranimals, as well as human.
        • According to WHO, the H5N1 was first discovered in humans in 1997 and has killed almost 60% of those infected. Though, it is not known to transmit easily among humans, the risk remains.
      • A-H7N9: It was reported in China in 2013. An outbreak of H7N9 strain killed around 300 people in 2016 and 2017.
    • Risk Factors for human infections
      • The primary risk factor for human infection appears to be direct or indirect exposure to infected live or dead poultry or contaminated environments, such as live bird markets.
    • Impacts
      • Outbreaks of AI in poultry may raise global public health concerns due to their effect on poultry population, their potential to cause serious disease in people and their pandemic potential.
      • Can impact local and global economies and international trade.
    • Note
      • There is no evidence to suggest that the virus can be transmitted to humans through properly prepared poultry or eggs.

 

D) NISHAD

    • The National Institute of High Security Animal Diseases (NISHAD) of ICAR is a premiere institute of India for research on exotic and emerging pathogens in animals.
      • It came into existence on 8th Aug 2014 as an independent institute under ICAR, from its original status as High Security Animal Disease Laboratory (HADSL), a regional station of Indian Veterinary Research Institute (IVRI).
    • Recent updates:
      • ‘Inactivated low pathogenic avian influenza (H9N2) vaccine for chickens’, developed by scientists of ICAR-NISHAD, Bhopal was transferred to various private companies. (Dec 2022)

 

E) THE EUROPEAN UNION IS EXPERIENCING THE LARGEST BIRD FLU OUTBREAK IN EUROPE: REPORT BY EUROPEAN FOOD SAFETY AUTHORITY (EFSA) (2022 AND 2023)

More than 50 million birds culled between Oct 2021 to Sep 2022

 

F) FIRST CASE OF AVIAN FLU FOUND IN ANTARCTIC REGION (OCT 2023 )

  • Avian flu has been detected for the first time in Antarctic region and has raised concerns for birds and mammals which feed on these bids.
  • Which type?
    • Highly Pathogenic Avian Influenza (HPAI) was detected in brown skua (a predatory seabird) populations on Bird Island, South Georgia, making it the first known case in the Antarctic region.
  • The ongoing pandemic of HPAI H5N1 was first reported in 2022 in northern hemisphere. In July 2022, outbreaks were reported in northern hemisphere’s wildlife, especially seabirds.
  • Later in 2022 and 2023, HPAI H5N1 spread rapidly in south America and eventually to Antarctic and sub-Antarctic region.
  • Risk Assessment:
    • Sea-Gulls and Skuas are the most threatened avian group. They are followed by bird’s prey such as hawks and carcasses, terns and shorebirds.

Among marine mammals, fur seals and sea lions are reportedly most vulnerable, followed by southern elephant seals and dolphins.

19) NIPAH

 

A) NIPAH

    • Why in news?
      • There has been an outbreak of the deadly Nipah virus in Kerala which have infected five people and killed two of them (Sep 2023)
    • Introduction
      • According to WHO Nipah Virus (NiV) infection is a newly emerging zoonosis (a disease that can be transmitted from animals to humans) that can infect both humans and animals.
        • It is classified as a “highly pathogenic paramyxovirus” and handling it requires the highest grade of facilities called BS-4.
      • The natural host of the virus are fruit bats of the Pteropodidae family, Pteropus genus. Humans are generally infected by fruit bat or pigs. Human to human transmission is also known including in the hospital setting.
    • First identification
      • First identified during the outbreak of disease that took place in Kampung Sungai Nipah, Malaysia in 1998. In this case pigs were intermediate hosts. Since, then there have been several outbreaks even without intermediate hosts.
      • In India it was first detected in Siliguri in 2001 and Nadia in 2007. This was a spillover of the outbreak in Bangladesh.
      • Later in 2018, 19, 21 and again in 2023 it appeared in Kerala.
        • Why?
          • Kerala has several fruit plantations that host several species of bats.
          • Better health facilities in Kerala may be leading to better detection, surveillance etc., whereas in other states the cases may go undetected.
        • Note: In 2018, 21 and 2023, the outbreak occurred in Kozhikode district and in 2019 the outbreak was in Ernakulam district.
        • Why only in these districts?
          • Not clear. A 2021 study have found that Nipah virus as found to be in circulation in fruit bats in “many districts” in Kerala.
          • An ongoing national survey in 14 states by NIV Pune found NIPAH virus anti-body in 9 states, including Kerala, and the UT of Puducherry.
    • Symptoms of NiV can be neurological, respiratory and pulmonary. They include:
      1. Encephalitis (brain swelling) due to Inflammation of the brain
      2. Confusion, disorientation and even persistent drowsiness
      3. Headache, fever, nausea and dizziness (flu like symptoms)
    • Fatality: Around 40-70% depending on the local capability for epidemiological surveillance and clinical management.
    • Prevention (Avoid date palm sap; avoid close contact with NiV Patient; avoid direct contact with pigs/bats in endemic area)
    • Treatment / Vaccine
      • Intensive Support care (no treatment or vaccine is available)

According to NCDC (National Centre for Disease Control), Ribavirin, an antiviral, may have a role in reducing mortality among patients with encephalitis caused by NIPAH virus disease.

 

B) WHY ZOONOTIC DISEASES ARE INFECTING HUMANS MORE AND MORE

  • Introduction
    • According to WHO, more than 300 zoonotic diseases have been observed over the past 70 years. It constitutes about 60% of all human diseases and 75% of all the Emerging Infectious diseases. The last decade has been worst and have caught the humans unprepared. Some recent examples are that of Ebola, Zika, Nipah, Kyasanur Forest disease etc.
  • Why increase in zoonotic diseases?
    • Dramatic increase in population and mobility -> Environmental changes, Deforestation etc. -> increase human contact with pathogens.
    • Increased demand for animal protein
      • Livestock production is moving closer to towns in the form of poultry farms etc.
    • Rise in intense and unsustainable farming
    • Increased use and exploitation of wildlife
    • Unsustainable utilization of natural resources
    • Many Indian villages are located within or around forests
      • Thus, significant number of people interact with forests in their day-to-day lives
    • Global Warming
      • Increases the population of insects like ticks that harbour and transfer the virus
    • Poor Preparation in terms of infra and human resource
      • Zoonotic diseases become more problematic in countries where health infrastructure is poor (e.g., Ebola in Africa, Zika in South America, Nipah in Asia etc.)
    • Lack of awareness especially in rural areas also

20) HEPATITIS

  • About Hepatitis
    • Hepatitis refers to inflammatory condition of liver. It’s commonly caused by viral infections, but there can be other causes too (e.g., auto-immune hepatitis that occurs as a secondary result of medication, drugs, toxins etc.)
  • 5 Types of Viral Hepatitis
    • Hepatitis A, B, C, D, and E.
      • A different virus is responsible for each of these types.
    • Hepatitis A by Hepatitis A Virus (HAV)
      • Transmitted by consuming food or water contaminated by faeces from a person infected with hepatitis A.
    • Hepatitis B (HBV) is transmitted through contact with infectious body fluids, such as blood, vaginal secretion, semen etc.
    • Hepatitis C (HCV) is transmitted through direct contact with infected blood fluids typically through injection drug use and sexual contact.
      • Injecting drug use is a major contributor to the number of people newly infected with Hepatitis C globally.
    • Hepatitis D (HDV), also called Delta Hepatitis is transmitted through direct contact with infected blood.
    • Hepatitis E (HEV), is mostly found in areas with poor sanitation and typically results from injecting fecal matter that contaminates the water supply.
  • Hepatitis B and C are responsible for more than 96% of cases.
    • Vaccine for Hepatitis B is available
    • Vaccine for Hepatitis C is not available
  • National Viral Hepatitis Control Program (launched in July 2018)
    • By MoH&FW
    • It is aimed at eliminating the deadly condition by 2030.
    • It has been launched in collaboration with WHO.
    • Under the program, government will be providing free drugs and diagnosis for Hepatitis B and C.
    • Key strategies under the program include – Preventive and promotive intervention through awareness generation; safe injection practices; sanitation and hygiene; safe drinking water; infection control and immunization; collaboration and coordination among different ministries; access to testing and management; building capacities at district, state, and national levels.
  • World Hepatitis Day – 28th July
    • Aims at raising awareness of hepatitis (A,B,C,D,E) and encourage prevention, diagnosis and treatment.
    • World Hepatitis Day is one of the 8 global public health campaigns marked by WHO, along with World Health Day (7th April), World Blood Donor Day (14th June), World Immunization Week (last week of April), World Tuberculosis Day (24th March), World No tobacco day (31st May), World Malaria Day (25th April), and World Aids Day (1st December)

21) NOROVIRUS

  • Norovirus:
    • Norovirus is thought to be the most common cause of acute gastroenteritis (diarrhea and vomiting illness) around the world. It spreads easily through food and drink and can have a big impact on people’s health.
    • Noroviruses also are sometimes called food poisoningbecause they can be transmitted through contaminated food. They aren’t always the result of food contamination.
  • Transmission of Norovirus:
    • Having direct contact with an infected person.
    • Consuming contaminated food or water or touching contaminated surface.
  • Symptoms: Diarrhea, Vomiting, Nausea, and Stomach Pain.
  • Prevention:
    • General Hygiene: Regular hand wash; rinse fruits and vegetables etc.
    • Treatment: Not available – generally goes away on its own within 1 to 3 days.

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September 2, 2024

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September 3, 2024

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