Emerging and Re-emerging Diseases - PowerPoint Presentation

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Emerging and Re-emerging Diseases

Dr.

Urfi

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COVID-19

Zika

AIDS

Avian InfluenzaEbolaMarburg CholeraRift Valley FeverTyphoidTuberculosisLeptospirosisMalaria ChikungunyaDengue, JEAntimicrobial resistance

UP

Guinea worm

Smallpox

Yaws Poliomyelitis Measles Leprosy Neonatal tetanus

DOWN

Infectious Diseases:

A World in Transition

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WHO Warns The Trends

WHO warned in its 2007 report that infectious diseases are emerging at a rate that has not been seen before

Since the 1970s, about 40 infectious diseases have been discovered, including

SARS, Ebola, Avian flu, and Swine flu

People traveling much more frequently and far greater distances than in the past, the potential for emerging infectious diseases to spread rapidly and cause global epidemics is a major concern3

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Direct economic impact of selected infectious disease outbreaks, 1990-2003

Heymann

DL. Emerging and re-emerging infections. In Oxford Textbook of Public Health, 5

th

ed, 2009, p1267Direct Economic Impact On Countries

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Emerging Diseases

“New diseases; new problem (New threats)”

Are those whose incidence in humans has increased during the last two decades or which threaten to increase in the near future

Also refers to

Newly appearing infectious diseasesDiseases that are spreading to new geographical areas

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Re-Emerging Diseases“Old diseases, new problem (New threats)”

Diseases which were previously easily controlled by chemotherapy and antibiotics, but now they have developed antimicrobial resistance and are often appearing in epidemic form

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Emerging & Re-Emerging Diseases

Red

-

Emerging

Blue-Re-emerging ds.

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Factors Contributing To Emergence & Re-Emergence Of DiseasesAGENT

Evolution of pathogenic infectious agents

(microbial adaptation & change)

Development of resistance to drugs

Resistance of vectors to pesticides

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Host FactorsHuman demographic change (inhabiting new areas)

Human

behaviour

(sexual & drug use)

Human susceptibility to infection (Immunosuppression)Poverty & social inequalityMethods of food preparation and storage in the home

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Environmental Factors

Climate & changing ecosystems:

Global warming- spread of Malaria, Dengue,

Leishmaniasis

, FilariasisEconomic development & Land use (urbanization, deforestation): Forces animals into closer human contact- increased possibility for agents to breach species barrier between animals & humansTechnology & industry (food processing & handling)Natural disasters: Malaria, Cholera

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CONTD.Migration of population

International travel & commerce

Breakdown of public health measure (war, unrest, overcrowding)

Deterioration in surveillance systems (lack of political will)

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Poverty, Neglect & Weakening of Health InfrastructurePoor populations: Major reservoir & source of continued transmission

Poverty- Malnutrition: Severe infectious disease cycle

Lack of funding, Poor prioritization of health funds, Misplaced in curative rather than preventive infrastructure, Failure to develop adequate health delivery systems

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Transmission of Infectious Agent from Animals to Humans

>2/3

rd

emerging infections originate from animals- Wild & domestic

Emerging Influenza infections associated with Geese, Chicken & PigsAnimal displacement in search of food after deforestation/ climate change (Lassa fever)Humans themselves penetrate/ modify unpopulated regions- come closer to animal reservoirs/ vectors (Yellow fever, Malaria)

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Human Behaviour

Unsafe sexual practices: HIV, Gonorrhea, Syphilis

Changes in agricultural & food production patterns: Food-borne infectious agents (E. coli)

Increased international travel (Influenza)

Outdoor activity

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Antimicrobial Drug ResistanceCauses:

Faulty prescription

Non-adherence by patients

Counterfeit drugs

Use of anti-infective drugs in animals & plants

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LEADS TO...Loss of effectiveness of drug

Community-acquired Infections: TB,

Pneumococcus

Hospital-acquired Infections:

Enterococcus, StaphylococcusProlonged hospital admissionsHigher death rate from infectionsRequires more expensive, more toxic drugsHigher health care costs

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Drug resistant strainsM.tuberculosis to ATT

Plasmodium parasites particularly of

falciparum

to anti-malarial

Enterococci to beta-lactams & aminoglycosidesStaphylococci to almost all drugsStreptococci, Pneumococci, H.influenzaeN.gonorrhoeae to penicillins & tetracyclinesShigella & Salmonella

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HUMAN

ANIMALS

ENVIRONMENT

VECTORS

Zoonosis

Population

Growth

Mega-cities

Migration

Exploitation

Pollution

Climate change

Vector

proliferation

Vector

resistance

Transmission

Antibiotics

Intensive

farming

Food

production

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Emerging Infectious DiseasesHepatitis C

First identified in 1989

In mid 1990s global prevalence 3%

Hepatitis B

Identified several decades earlierUpward trend in all countriesPrevalence >90% in high-risk populationAIDS (Acquired immune deficiency syndrome)

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COVID-19Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus

First case can be traced back to November, 2019 in China

Spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes

India has more than 9 lac cases at present (15.07.20)

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Zika virus diseaseMosquito (Aedes

)-borne

flavivirus

first identified in Uganda in 1947

The first large outbreak reported from the Island of Yap (Federated States of Micronesia) in 2007In July 2015 Brazil reported an association between Zika virus infection and Guillain-Barré syndrome In October 2015 Brazil reported an association between Zika virus infection and microcephaly

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Ebola Virus DiseaseEbola Hemorrhagic Fever

Ebola (5 species)

Sudan, Zaire, Tai, Reston,

Bundibugyo

First appearance in 1976 in Zaire & SudanSporadic outbreaks Recent epidemic in Guinea in 2013 & spread to South AfricaCase fatality can be as high as 70%Human to human transmission through or body fluids of an infected symptomatic person or through contaminated sharp

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HantavirusStarted in 1993 as Pulmonary syndrome in United States

Case fatality of over 50%

Also surfaced in Argentina & Brazil

Carried by rodents particularly deer mice

May cause haemmorhagic disease with renal failure

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InfluenzaThreat of new global pandemic

Major shift in influenza virus every 20 years

Epidemic strains originate from China

Carried by ducks, chicken & pigs

Highly Pathogenic Avian Influenza (H5N1) has pandemic potentialIn 2002 SARS was reported from China with rapid spread to Hongkong, Singapore, VietnamMore recently pandemic due to Influenza A (H1N1) from 2009

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MarburgVarying pathogenicity (mortality ranging from 21-80%)

Responsible for 1967 outbreak in Europe

Outbreaks in 2000 in Democratic Republic of the Congo and 2005 in Angola

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Re-Emerging Infectious Diseases

Diphtheria:

Early 1990s epidemic in Eastern Europe (1980-1% cases; 1994- 90% cases)

Cholera:

100% increase worldwide in 1998 (new strain Eltor, 0139)Human Plague: India (1994) after 15-30 years absence Dengue/ DHF: Over past 40 years, 20-fold increase to nearly 0.5 million (between 1990-98)

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Creutzfeldt-Jakob diseaseCJD is called a human form of mad cow disease (bovine spongiform encephalopathy or BSE)

British beef market severely affected

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Control of Emerging and Re-emerging Diseases

Diagnosis of the disease

Controlling the reservoir & Interrupting the transmission

Protecting the susceptible host

Encouraging research initiations for treatment regimens and diagnostics

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Cont…Encouraging research for new methods of control measures including vector control & prevention of epidemics

Strengthening of the disease surveillance system

Establishment of drug resistance surveillance

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GOARNGlobal Outbreak Alert & Response Network

Coordinated by WHO

Mechanism for combating international disease outbreaks

Ensure rapid deployment of technical assistance, contribute to long-term epidemic preparedness & capacity building

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What skills are needed?

Multiple expertise needed

!

Infectious diseases

Epidemio-

logy

Public Health

International field experience

Information management

Laboratory

Telecom. & Informatics

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Public health measures to prevent infectious diseases

Safe water & Proper Sewage treatment & disposal

Food safety

programme

Animal control programme Vaccination programmePublic health organization

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Thank you…