VIRUSES

1]Infecting CNS-Japanese encephalitis

2]Infecting RESPIRATORY SYSTEM

-SARS

-Pandemic influenza

History

Geographical distribution

Transmission

Clinical features

Diagnosis and Treatment

Prevention and Control

Genus Flavivirus

Name derived from

the Latin flavus meaning “yellow”

Single stranded, enveloped RNA virus

Morphology not well defined

Different genotypes with single serotype

Replication-Regional lymphnodes

Invasion of CNS-via-Blood

I.P-5 to 15 days

1940 to 1978

› Disease spread with epidemics in China,

Korea, and India [Tamilnadu-1955]

Endemic in

temperate and

tropical regions of

Asia

Disease control by

vaccination

Japan

China

Korea

Indonesia

India Philippines

The three southern states of Tamil Nadu (TN), Andra Pradesh, Karnataka were reporting higher incidence.

JE is emerging as a public health problem in Kerala

In a few villages of Cuddalore district of Tamil Nadu, a known JE-endemic area (Chidambaram, Virudhachalam, Thittakudi)

Vector-borne

Enzootic cycle

› Mosquitoes: Culex species

Culex tritaeniorhynchus

› Reservoir/amplifying hosts

Pigs, bats, Ardeid (wading) birds

Possibly reptiles and amphibians

› Incidental hosts

Horses, humans, others

Center for Food Security and Public Health, Iowa State University, 2011

35,000-50,000 cases annually

Most asymptomatic or mild signs

Children and elderly

› Highest risk for severe disease

Center for Food Security and Public Health, Iowa State University, 2011

Prodromal stage: 1-6 days

Acute encephalitis

› Headache, high fever, stiff neck, stupor

› May progress to paralysis, seizures,

convulsions, coma, and death

Neuropsychiatric sequelae

› 45 to 70% of survivors

In utero infection possible

› Abortion of fetus

Laboratory diagnosis required

Tentative diagnosis

› Antibody titer: HI, IFA, CF, ELISA

› JE-specific IgM in serum or CSF

Definitive diagnosis

› Virus isolation: CSF, brain

No specific treatment

› Supportive care

Vector control

› Eliminate mosquito breeding areas

› Adult and larvae control

Vaccination

› Equine, swine, humans

Personal protective measures

› Avoid prime mosquito hours

› Use of repellants containing DEET

Center for Food Security and Public Health, Iowa State University, 2011

o Caused By- Varient of corona virus

o Emerging disease-2002-03

o Rapid spread in asian countries

o WHO-8422 cases

-916 deaths from 30 countries

o MOT-Respiratory dropletso -Direct contact

-Possible fecal tranmission

o I.P-2 to 7 days

High fever

Virus isolation: inoculate suitable cell culture with patient specimens

When infected by SARS-CoV antibodies

(e.g. IgM and IgG) are produced /

change in level

Enzyme-linked immunosorbent assay

(ELISA)

Immunofluorescence assay (IFA):

Clinical history & observation

Chest radiography: important role

› 70-80% patients have abnormal chest

radiographs

o Immunomodulatory therapy

-Corticosteroido Antiviral Agents

-Ribavirin

oProtease inhibitor -Lopinavir-ritonavir co-formulation

Principle: to break the chain of transmission from infected to healthy person

3-step protocol of disease confinement› Case detection

› Prompt isolation

› Contract tracing Daily health check

Voluntary home isolation

Creation of emergency operating center

Institutional support

› Efficient quarantine measures

› Legislation

International collaboration—WHO

› Travel alerts and restrictions

› Coordination for research

› Agreement of countries on containment

protocol

Seasonal Influenza

› A public health problem each year

› Usually some immunity built up from previous exposures to the same subtype

› Infants and elderly most at risk

Influenza Pandemics

› Appear in the human population rarely and unpredictably

› Human population lacks any immunity

› All age groups, including healthy young adults

Seasonal Epidemics vs. Pandemics

1920 1940 1960 1980 2000

H1N1

H2N2

H3N2

1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu”

20-40 million deaths 1-4 million deaths 1-4 million deaths

The new virus must be efficiently transmitted from one human to another

A new influenza virus emerges to

which the general population has

little/no immunity

The new virus must be able to replicate

in humans and cause disease

Viral Re-assortment

Reassortment in pigs

Reassortment in

humans

Pandemic Influenza

Virus

Human Influenza

Type of infection Upper and lower respiratory

Fever Yes

Headache Yes

Cough Yes

Respiratory symptoms Varies; sore throat to difficulty

breathing

Gastrointestinal

symptoms

Uncommon, except children,

elderly

Recovery 2-7 days

Isolation Precautions

Source: Rosie Sokas, MD MOH UIL at

Chicago

Droplet precautions:

Surgical Masks

Personal Protective Equipment

(PPE)

Thank you