×

14 June, 2020

53 Min Read

Paper Topics Subject
GS-III India may have undercounted COVID-19 cases
COVID-19 taking an emotional toll on children
Hydroxychloroquine does not reduce mortality, RECOVERY trial finds
Persistent global transmission of chikungunya from India
Vector-borne diseases
PT Pointer Great Oxidation Event (GOE) Human Geography
Baby Dragons
GS-III :
India may have undercounted COVID-19 cases

India may have undercounted COVID-19 cases

  • The findings of a serological survey by the Indian Council of Medical Research (ICMR) from 69 districts across 21 States indicate that an estimated 7,00,000 people could have been infected by the SARS-CoV-2 virus in these districts even in early May.
  • The number indicated by the survey is twenty times higher than the 35,000 confirmed cases of COVID-19 reported as of early May in the entire country, suggesting that the actual COVID-19 count overall could be underestimated by a factor of at least 20.
  • Confirmed infections have since swelled to more than 3,08,000 as of Friday (June 12), with more than 8,900 people having died of the disease.

Tested for antibodies

  • The research paper published in May in the ICMR's in-house Indian Journal of Medical Research describing the methodology of the survey, blood samples of 24,000 adults were examined for antibodies produced specifically for SARS-CoV-2 via an ELISA test .
  • The survey revealed that 0.73% of the population showed evidence of IgG antibodies.
  • The survey began around May 12 and given that it takes an average of two weeks for IgG antibodies to be detected.
  • The adult population of these districts according to the 2011 census was 60% of the overall population (160 million) and this works out to around 96 million persons.
  • If the results of the survey are applied to the adult population of these districts, the total number of people likely to have infected by the virus adds up to 7,00,000; the numbers could be even higher if the growth of the population in the last nine years is factored in.

Indirect evidence

  • Antibodies produced in response to being infected by the virus confer immunity but are also evidence of being exposed to the infection.
  • Because they rely on blood samples and are only an indirect evidence of the presence of the virus, they aren’t as accurate as PCR tests.
  • Two values called sensitivity and specificity — that are a measure of the proportion of cases mis-identified or outright missed — determine the accuracy of the test.
  • Academic literature has suggested that there is a higher chance of “false positives” being reflected in serological surveys if there is a low prevalence of the disease.
  • The scientist that The Hindu spoke to said while the prevalence percentage accounted for the limitations of this test, 7,00,000 was an “accurate estimate” of the level of infection in these districts. The test has been developed and validated by the ICMR-National Institute of Virology and is said to be the most reliable so far.
  • Community transmission has been evident for long.

 

Source: TH

Print PDF

GS-III :
COVID-19 taking an emotional toll on children

COVID-19 taking an emotional toll on children

Context

  • The fear of losing loved ones to the coronavirus (COVID-19) infection is most apparent among children who dabble with immense anxiety and emotional stress brought by the ongoing pandemic and lockdown.
  • Doctors say that the toll on the mental health of the young ones is way more than the physical symptoms of COVID-19.

Stress and anxiety rise amid coronavirus pandemic

  • Every age group is processing the events in a different way,” said Dr. Soonu Udani from SRCC Children’s Hospital, that has treated over 45 minors with COVID-19 over the past weeks.
  • She said that children below 10 years don’t know much and are picking up tiny bits from the television and family conversations, while those above 10 years have more fear of death as they try to comprehend the severity of the infection.

Struggle to understand

  • As most children are asymptomatic or display mild symptoms, they also struggle to reason why they have to be hospitalised.
  • The hospital has started using play therapy, drawings and charts to tell children about the virus, and the importance of being in isolation or quarantine.

Parenting in a post-COVID world

  • Two to three-year olds, separated from their parents, show signs of anxiety through extreme clinginess after their parents return from quarantine.
  • “A mother told me that her child is not even letting her go to the bathroom. In slightly older children, three to six-year-olds, a common thought is ‘did I do something wrong that my parents went away’,” said Dr. Sengupta.
  • Teenagers are also facing a hard time with lack of social circle and no privacy at home.
  • It was important for parents and caregivers to not brush aside the queries of their children.

Psychosomatic symptoms

  • In some cases, children whose family members had COVID-19, reported abdominal pain, twisting of neck, headaches and myalgia or muscle pain, but as soon as their report returned negative, they start feeling better.
  • “We have seen four such cases of psychosomatic symptoms in children who were anxious due to a family member testing positive,” said Bengaluru-based child neurologist Dr. Minal Kekatpure.
  • The interaction with doctors and nurses clad in alien-looking PPE suits fascinates children but also frightens some of them.

Source: TH

Print PDF

GS-III :
Hydroxychloroquine does not reduce mortality, RECOVERY trial finds

Hydroxychloroquine does not reduce mortality, RECOVERY trial finds

Recovery trial

  • The RECOVERY trial, a large randomised controlled trial in the U.K. to test five drugs, including hydroxychloroquine, has found no clinical benefit from use of hydroxychloroquine in hospitalised patients with COVID-19.
  • The trial investigators found that there was no significant benefit in mortality reduction in the intervention group, which was the primary objective.
  • The RECOVERY trial began in March.
  • It is a dynamic trial assessing five candidate drugs and convalescent plasma therapy for treating COVID-19 in patients in U.K. hospitals. The trial has enrolled over 11,000 patients.
  • On June 4, following the retraction of The Lancet paper on use of hydroxychloroquine, the U.K. Medicines and Healthcare Products Regulatory Agency wanted the independent Data Monitoring Committee of the RECOVERY trial to carry out an additional review.
  • It also asked the investigators to look at the unblinded data in the hydroxychloroquine arm.

No beneficial effects

  • It then came to light that the drug did not have the desired beneficial effects
  • According to the release, a total of 1,542 patients were randomised to receive hydroxychloroquine for 10 days while 3,132 patients in the control arm received only standard care.
  • The researchers found that there was “no significant difference in the primary endpoint of 28-day mortality”.
  • While mortality was 25.7% in the intervention group (who were administered HCQ), the control group had 23.5% mortality, which is not statistically significant.

Outcomes measured

  • The primary outcome tested was reduction in all-cause mortality within 28 days of randomisation.
  • The secondary outcomes measured were to assess any reduction in duration of hospital stay and need for and duration of ventilator or ECMO within 28 days and up to six months after randomisation.

Huge speculation

  • Deputy Chief Investigator Martin Landray from the University of Oxford says: “There has been huge speculation and uncertainty about the role of hydroxychloroquine as a treatment for COVID-19, but an absence of reliable information from large randomised trials.
  • The preliminary results from the RECOVERY trial are quite clear — hydroxychloroquine does not reduce the risk of death among hospitalised patients with this new disease.”

Post-exposure prophylaxis

  • Another trial found that hydroxychloroquine drug was not effective even as a post-exposure prophylaxis in asymptomatic participants who have had high-risk exposure with a confirmed COVID-19 case.
  • Nearly 88% (719 of 821 participants) had such high-risk exposure.
  • The results of the trial published in The New England Journal of Medicine found that the incidence of COVID-19 illness was not statistically significant in the group that received the drug compared with the control group.
  • While 49 of 414 (11.8%) participants who received the drug developed illness, 58 of 407 (14.3%) participants who got the placebo fell ill.
  • Side-effects were more in the intervention group but no serious adverse events were reported.

Source: TH

Print PDF

GS-III :
Persistent global transmission of chikungunya from India

Persistent global transmission of chikungunya from India

Context

  • Studying the geographic distribution and evolution of the chikungunya virus over the period from 2005-2018, a team from ICMR-National Institute of Virology, Pune, has noted India as an endemic reservoir for the virus with persistent global transmissions from the country.
  • The paper published recently in Infection, Genetics and Evolution adds that “dispersal of the strains from India was noted to neighbouring and distant countries” such as Sri Lanka, Bangladesh and China.
  • The team studied newly sequenced chikungunya viruses isolated during outbreaks that happened between 2014 and 2018. During these years, the virus showed activity in India. Karnataka, Maharashtra and New Delhi accounted for a majority of the cases.

Indian Ocean lineage

  • The whole-genome sequencing study revealed that the isolates belonged to the Indian subcontinent sub-lineage of the Indian Ocean lineage.
  • The Indian Ocean lineage is a subgroup within the East Central South African genotype.
  • It was responsible for the resurgence in the epidemic on La Reunion island and other neighbouring islands in the Indian Ocean and in the Indian sub-continent during 2004-2005.
  • This study helped understand the overall evolution and epidemiology of the Indian Ocean lineage.
  • Analyses of about 207 whole genomes, including the eleven whole genomes of this study and 39 additional whole genomes from India, showed two separate clusters of Indian Ocean islands sub-lineage and Indian subcontinent sub-lineage.
  • It is already known that Kenya was the most likely ancestral location for both the sub-lineages, and the study further confirmed this.

Spread from clusters

  • Observations from the phylogeography study (Phylogeography is the study of the historical processes that may be responsible for the contemporary geographic distributions of individuals) based on the genome sequences over the period from 2005 to 2018, showed persistent global transmissions from India.
  • The strains from these clusters were noted to have spread to China, Sri Lanka, Bangladesh, and Southeast Asian countries including Indonesia, Malaysia, Singapore and Papua New Guinea beyond mid-2006.
  • Transmissions to Yemen, China, Japan, Hong Kong, Pakistan, Australia, Bangladesh and Italy were also noted later on.
  • Further studies of the chikungunya sequences revealed indigenous evolution in India at least at three time points over the period 2005-2018, with specific mutations that conferred viral fitness in the Aedes vector species.
  • There is a possibility of further diversification as this is an RNA virus and continues to acquire mutations.

 

Source: TH

Print PDF

GS-III :
Vector-borne diseases

Vector-borne diseases

Key facts

  1. Vector-borne diseases account for more than 17% of all infectious diseases, causing more than 700 000 deaths annually. They can be caused by either parasites, bacteria or viruses.
  2. Malaria is a parasitic infection transmitted by Anopheline mosquitoes. It causes an estimated 219 million cases globally, and results in more than 400,000 deaths every year. Most of the deaths occur in children under the age of 5 years.
  3. Dengue is the most prevalent viral infection transmitted by Aedes mosquitoes. More than 3.9 billion people in over 129 countries are at risk of contracting dengue, with an estimated 96 million symptomatic cases and an estimated 40,000 deaths every year.
  4. Other viral diseases transmitted by vectors include chikungunya fever, Zika virus fever, yellow fever, West Nile fever, Japanese encephalitis (all transmitted by mosquitoes), tick-borne encephalitis (transmitted by ticks).
  5. Other vector-borne diseases such as Chagas disease (transmitted by triatomine bugs), leishmaniasis (sandflies) and schistosomiasis (snails) affect hundreds of millions of people worldwide.
  6. Many of vector-borne diseases are preventable, through protective measures, and community mobilisation.

Vectors

  • Vectors are living organisms that can transmit infectious pathogens between humans, or from animals to humans.
  • Many of these vectors are bloodsucking insects, which ingest disease-producing microorganisms during a blood meal from an infected host (human or animal) and later transmit it into a new host, after the pathogen has replicated.
  • Often, once a vector becomes infectious, they are capable of transmitting the pathogen for the rest of their life during each subsequent bite/blood meal.

Vector-borne diseases

  • Vector-borne diseases are human illnesses caused by parasites, viruses and bacteria that are transmitted by vectors.
  • The burden of these diseases is highest in tropical and subtropical areas, and they disproportionately affect the poorest populations.
  • Since 2014, major outbreaks of dengue, malaria, chikungunya, yellow fever and Zika have afflicted populations, claimed lives, and overwhelmed health systems in many countries.
  • Other diseases such as Chikungunya, leishmaniasis and lymphatic filariasis cause chronic suffering, life-long morbidity, disability and occasional stigmatisation.

List of vector-borne diseases, according to their vector

The following table is a non-exhaustive list of vector-borne disease, ordered according to the vector by which it is transmitted. The list also illustrates the type of pathogen that causes the disease in humans. 

Vector

Disease caused

Type of pathogen

Mosquito

Aedes

Chikungunya

Dengue

Lymphatic filariasis

Rift Valley fever

Yellow Fever

Zika

Virus

Virus

Parasite

Virus

Virus

Virus

Anopheles

Lymphatic filariasis

Malaria

Parasite

Parasite

Culex

Japanese encephalitis

Lymphatic filariasis

West Nile fever

Virus

Parasite

Virus

Aquatic snails

Schistosomiasis (bilharziasis)

Parasite

Blackflies

Onchoceriasis (river blindness)

Parasite

Fleas

Plague (transmitted from rats to humans)

Tungiasis

Bacteria

Ecto parasite

Lice

Typhus

Louse-borne relapsing fever

Bacteria

Bacteria

Sandflies

Leishmaniasis

Sandfly fever (phlebotomus fever)

 

Bacteria

Virus

Ticks

Crimean-Congo haemorrhagic fever

Lyme disease

Relapsing fever (borreliosis)

Rickettsial diseases (eg: spotted fever and Q fever)

Tick-borne encephalitis

Tularaemia

Virus

Bacteria

Bacteria

Bacteria

Virus

Bacteria

Triatome bugs

Chagas disease (American trypanosomiasis)

Parasite

Tsetse flies

Sleeping sickness (African trypanosomiasis)

Parasite

 

WHO response

  • The "Global Vector Control Response (GVCR) 2017–2030" was approved by the World Health Assembly in 2017. It provides strategic guidance to countries and development partners for urgent strengthening of vector control as a fundamental approach to preventing disease and responding to outbreaks.
  • To achieve this a re-alignment of vector control programmes is required, supported by increased technical capacity, improved infrastructure, strengthened monitoring and surveillance systems, and greater community mobilization.

Specifically WHO responds to vector-borne diseases by:

  • providing evidence-based guidance for controlling vectors and protecting people against infection;
  • providing technical support to countries so that they can effectively manage cases and outbreaks;
  • supporting countries to improve their reporting systems and capture the true burden of the disease;
  • providing training (capacity building) on clinical management, diagnosis and vector control with support from some of its collaborating centres; and
  • supporting the development and evaluation of new tools, technologies and approaches for vector-borne diseases, including vector control and disease management technologies.

A crucial element in reducing the burden of vector-borne diseases is behavioural change. WHO works with partners to provide education and improve public awareness, so that people know how to protect themselves and their communities from mosquitoes, ticks, bugs, flies and other vectors.

Access to water and sanitation is a very important factor in disease control and elimination. WHO works together with many different government sectors to improve water storage, sanitation, thereby helping to control these diseases at the community level.

 

National Vector Borne Disease Control Programme

Launched in 2003-04 by merging National anti -malaria control programme ,National Filaria Control Programme and Kala Azar Control programmes .Japanese B Encephalitis and Dengue/DHF have also been included in this Program Directorate of NAMP is the nodal agency for prevention and control of major Vector Borne Diseases

List of Vector Borne Diseases Control Programme Legislations:

1)    National Anti - Malaria programme

2)    Kala - Azar Control Programme

3)    National Filaria Control Programme

4)    Japenese Encephilitis Control Programme

5)    Dengue and Dengue Hemorrhagic fever

 

1)    NATIONAL ANTI - MALARIA PROGRAMME

  • Malaria is one of the serious public health problems in India. At the time of independence malaria was contributing 75 million cases with 0.8 million deaths every year prior to the launching of National Malaria Control Programme in 1953. A countrywide comprehensive programme to control malaria was recommended in 1946 by the Bhore committee report that was endorsed by the Planning Commission in 1951. The national programme against malaria has a long history since that time. In April 1953, Govt. of India launched a National Malaria Control Programme (NMCP).

2)    KALA -AZAR CONTROL PROGRAMME

  • Kala-azar or visceral leishmaniasis (VL) is a chronic disease caused by an intracellular protozoan (Leishmania species) and transmitted to man by bite of female phlebotomus sand fly.Currently, it is a main problem in Bihar, Jharkhand, West Bengal and some parts of Uttar Pradesh. In view of the growing problem planned control measures were initiated to control kala-azar.

3)    NATIONAL FILARIA CONTROL PROGRAMME

  • Bancroftian filariasis caused by Wuchereria bancrofti, which is transmitted to man by the bites of infected mosquitoes - Culex, Anopheles, Mansonia and Aedes. Lymphatia filaria is prevalent in 18 states and union territories. Bancroftian filariasis is widely distributed while brugian filariasis caused by Brugia malayi is restricted to 7 states - UP, Bihar, Andhra Pradesh, Orissa, Tamil Nadu, Kerala, and Gujarat. The National Filaria Control Programme was launched in 1955. The activities were mainly confined to urban areas. However, the programme has been extended to rural areas since 1994.

4)    JAPANESE ENCEPHALITIS CONTROL PROGRAMME

  • Japanese encephalitis (JE) is a zoonotic disease and caused by an arbovirus, group B (Flavivirus) and transmitted by Culex mosquitoes. This disease has been reported from 26 states and UTs since 1978, only 15 states are reporting JE regularly. The case fatality in India is 35% which can be reduced by early detection, immediate referral to hospital and proper medical and nursing care. The total population at risk is estimated 160 million. The most disturbing feature of JE has been the regular occurrence of outbreak in different parts of the country.
  • Govt. of India has constituted a Task Force at National Level which is in operation and reviews the JE situations and its control strategies from time to time. Though Directorate of National Anti-Malaria Programme is monitoring JE situation in the country.

5)    DENGUE AND DENGUE HEMORRHAGIC FEVER

  • One of the most important resurgent tropical infectious disease is dengue. Dengue Fever and Dengue Hemorrhagic Fever (DHF) are acute fevers caused by four antigenically related but distinct dengue virus serotypes (DEN 1,2,3 and 4) transmitted by the infected mosquitoes, Aedes aegypti. Dengue outbreaks have been reported from urban areas from all states. All the four serotypes of dengue virus (1,2,3 and 4) exist in India. The Vector Aedes Aegypti breed in peridomestic fresh water collections and is found in both urban and rural areas.

Source: WHO

Print PDF

GS-I : Human Geography
Great Oxidation Event (GOE)

Great Oxidation Event (GOE)

  • The atmosphere of early Earth contained little molecular oxygen. A significant increase in oxygen occurred ca. 2.4–2.0 billion years ago in what is called the Great Oxidation Event (GOE).
  • A large positive excursion in carbon isotopic composition in sedimentary carbonates is known to have occurred 2.2–2.0 billion years ago (the Lomagundi-Jatuli event), which provides evidence for an enhanced rate of organic carbon burial, i.e., enhanced net production of oxygen.
  • The Proterozoic snowball Earth event (global glaciation) occurred 2.3–2.2 billion years ago, roughly coinciding with the GOE.
  • Thus, a causal relationship between the GOE and the snowball Earth event has been suggested.
  • The snowball Earth event could have been triggered by an increase in oxygen in the atmosphere because it would have resulted in a significant reduction of atmospheric methane level, thereby reducing the greenhouse effect of the atmosphere and causing global glaciation.
  • On the other hand, termination of the snowball Earth event may have triggered the production of a large amount of oxygen because the extremely hot climate (~60 °C) immediately after the termination of the snowball Earth event must have significantly increased the supply of phosphate to the oceans, resulting in large-scale blooms of cyanobacteria, which could have produced large amounts of oxygen.
  • The postglacial transition of atmospheric oxygen levels may have promoted an ecological shift and biological innovations for oxygen-dependent life.

Source: TH

Print PDF

GS-III :
Baby Dragons

Baby Dragons

  • 2 rare aquatic creatures officially called proteus or olms,  also known as baby dragons, are going on display in aquarium at Slovenia’s Postojna Cave.
  • The Olms have pale pink skin, no eyesight, a long thin body and 4 legs.
  • They live only in the waters of dark caves of the Southern European Karst region.

Source: TH

Print PDF

Newsletter Subscription
SMS Alerts
x
Nature
x
Nature