ZOONOTIC AND CHILDHOOD VIRUSES

FLAVIVIRIDAE

SIZE: 40-50mm

STRUCTURE:

Positive-sense RNA

Icosahedral viruses

Nonsegmented

Enveloped

Single-stranded RNA

FLAVUS

Origins of name from Latin word____meaning “yellow”

Yellow fever, causing yellow jaundice in

humans

1ST IDENTIFIED DISEASE OF FLAVUS:

Arbovirus

TRANSMISSION OF FLAVIRIDAE: transmitted primarily via

mosquitoes.

zika fever, yellow fever, dengue, west

nile viral encephalitis, japanese

encephalitis, st. Louis encephalitis

FLAVIRIDAE diseases

HCV

EXCEPTION: it is a flavivirus but not an arbovirus

Monkey’s and Humans

YELLOW FEVER RESERVOIRS

Mosquito (Aedes aegypti, Haemagogus and Sabethes spp.)

YELLOW FEVER VECTORS

liver cells

YELLOW FEVER VIRUS TARGET

Fever, hemorrhage, jaundice

YELLOW FEVER PRIMARY SYMPTOMS

3-6 days after mosquito bite.

YELLOW FEVER Incubation period

 Nausea, vomiting, dusky pallor, facial

edema, swollen bleeding gums,

hemorrhagic tendencies (black vomit, melena, ecchymoses)

YELLOW FEVER PROGRESSION

Rapid deterioration w symptoms includes

5% to 50%

YELLOW FEVER PROGRESSION

Mortality Rate:

death usually withing 6 to 7 days post-onset;

rarely beyond 10 days.

YELLOW FEVER CRITICAL TIMEFRAME

Yellow Jaundice

YELLOW FEVER Characteristics symptoms in recovery

DENGUE

Prevalence

- Most prevalent arbovirus globally

- Leading cause of illness and death in the tropics and subtropical

countries.

- Primary resevoirs: Humans

- Transmission method:Mosquito Vector (Aedes aegypti)

DENGUE TRANSMISSION

DENGUE CONTROL METHODS

- Vector control (mosquito control)

- Early detection & access to medical care(reduces fatality rates to

below 1%).

Four serotypes

CLINICAL MANIFESTATIONS OF DENGUE

how many Serotypes

immunity only to that

specific serotype.

Infection with one serotype provides

immuneenhanced

disease (e.g., severe hemorrhagic fever or dengue shock

syndrome)

Subsequent infection with another serotype can cause

fever, arthritis, rash

DENGUE CLINICAL PRESENTATIONS FOR NONLETHAL

Hemorrhagic fever, dengue shock syndrome

CLINICAL PRESENTATIONS OF DENGUE

Severe:

DENGUE SYMPTOMS & PROGRESSION

Initial symptoms:

- Sudden fever, severe headache, general myalgia, chills.

- Macropapular rash often appears on the trunk, spreading to the

face and extremities.

NO available vaccine.

DENGUE VACCINE STATUS

Virus-specific IgM antibody presence

- Fourfold rise in specific IgG antibody

DENGUE LABORATORY TESTING

WEST NILE VIRUS

First isolated in the West Nile District of Uganda.

Bird-Mosquito cycle

Virus amplification during warm months

Birds

WEST NILD VIRUS NATURAL RESERVOIRS

Bridge Mosquitos

WEST NILE VIRUS TRANSMISSION

1. Blood transfusion

2. Human breast milk

3. Human transplantation

WEST NILE VIRUS HUMAN TRANSMISSION

Rhabdoviridae

RHABDOVIRIDAE FAMILY

Infects fish, arthropods, mammals,

and plants.

RHABDOVIRIDAE HOST

RHABDOVIRIDAE STRUCTURE

Bullet-shaped virion

Single-stranded RNA with a helical

nucleocapsid

Lipid bilayer envelope with spikelike

projections.

RABIES LYSSAVIRUS (RABV)

NEUROTROPIC VIRUS infecting all mammals.

Nearly always fatal upon infection, with rare exceptions

in musculoskeletal tissue or direct invasion

of peripheral nerves/nerve endings

RABV PATHOGENESIS

Initial multiplication

retrograde

axoplasmic flow.

RABV CNS INFECTION Progresses centripetally transneuronally via___________

second-order neurons

(mainly in brain & spinal cord)

RABV CNS INFECTION Spreads from first-order neurons to__________

non-nervous

tissue(eg., salivary glands)

RABV CNS INFECTION Eventually spreads to peripheral nerves and ___________

Prodromal Phase

RABV CLINICAL PRESENTATION

- Malaise, fever, fatigue, anorexia,

headache

- Pain or tingling

Progression

RABV CLINICAL PRESENTION

- Behavioral changes

- Coma and death.

NO definitive treatment

in RABV,_________once clinical symptoms appear

Prophylaxis

RABV Vaccines AVAILABLE- post exposure_________available

ANIMAL RABIES

Symptoms similar to Human Rabies: increased excitation.

1) Aggression, agitation 2) Lethargy, paralysis.

ANIMAL RABIES

Clinical Types

Filoviridae

Example of these viruses are Ebola virus & Marburg virus

Ebola virus & Marburg virus

most pathogenic and virulent Filoviridae

FILOVIRIDAE STRUCTURE

Pleomorphic

Rod-like

Enveloped

Nonsegmented

Negative-sense RNA

Single-stranded

FILOVIRIDAE MORPHOLOGY

Filamentous w various shapes(number 6, U or

circular.

Multisystem syndrome

FILOVIRIDAE VIRAL HEMORRHAGIC FEVER:

- conjunctivitis

- vomiting

- abdominal pain

- myalgia

- pharyngitis

- proteiniuria,

- severe hemorrhage.

VIRAL HEMORRHAGIC FEVER SYMPTOMS

Africa

RABV CLINICAL PRESENTATION ENDEMIC:

Ebola river in Zaire

Ebola Virus Origin:

Fruit Bats

Ebola virus natural reservoir:

Human and nonhuman primates (chimpanzees,

gorillas, monkeys)

Ebola Virus other reservoirs:

Bat excreta or bush meat

Ebola Virus transmission zoonotic

Contact with infectious body fluids

Ebolavirus Transmission Peron to Person

2-21 days post exposure

Ebola virus incubation period

Nonspecific febrile illness

Ebola virus initial symptoms

Severe GI symptoms, shock, hemorrhage, multiorgan

failure.

Ebola virus Progression

- NAAT (Nucleic acid amplification test)

- Rapid Antigen Detection Tests

EBOLA VIRUS TESTING METHODS

RT-PCR performed at the CDC

EBOLA VIRUS CONFIRMATORY TESTING

Available

Ebola virus vaccine is________

MARBURG VIRUS

Characteristic Morphology: “Shepered’s hook”

African fruit bat

Marburg Primary reservoir

- Zoonotic

- Person to person: Infected body fluids*

Marburg transmission

RT-CPR avail at CDC

MARBURG DIAGNOSIS

Paramyxoviridae

Often identified in young children: measles, mumps, nipah

virus andparainfluenza viruses.*

Cause respiratory disease*

Paramyxoviridae characteristics

Pleomorphic

Unsegmented genome

No antigenic shift*

Negative-sense RNA

Enveloped

Large (15-350nm)

Single-stranded RNA viruses

Sperical or filamentous*

MUMPS VIRUS

Acute, self-limiting disease.

Symptoms

- Fever, Fatigue, Parotitis

- Droplets and contaminated

fomites

Mumps Virus transmission

HUMANS

Mumps virus reservoir

Mump Virus epidemiology

- Vaccine AVAILABLE(current reformulation may be necessary)

- New circulating strains

16-18 days

Mump virus incubation:

Elevated temperature

- Enlargement of one or both parotid glands

- Nonspecific respiratory symptoms

Mumps virus symptoms

- Menigoencephalitis

- Orchitis, oophortis

- Polyarthritis, pancreatits.

Mumps Virus Progressions

Saliva, CSF, Oral fluid,

Urine or Throat*

Mumps virus samples

NAAT

Mumps vorus more sensitive diagnosis

CPE

Mumps virus Cell culture

Rounded & multinucleated

giant cells*

Previous vaccination

In Mumps,__________may reduce the

chances of virus isolation in culture

MEASLES VIRUS

- acute, generalized infection often accompanied by a rash.

Measles Virus Characteristics

- Pleomorphic

- Enveloped

- Nonsegmented

- Negative-sense RNA viruses

- Single-stranded

“Koplik spots”

In Measles,

Bluish white spots w red halo

- Buccal or labial mucosa)

EXANTHEMATOUS

Measles is one of six classic childhood

diseases that cause rash or skin eruption and is also a_______

- Rubella(German measles)

- Roseola

- Erythema infectiosum

- Scarlet fever

Other exanthems

1. Cough, Coryza, Conjunctivitis, Fever

2. Koplik spots

3. Erythematous rash

Measle Virus Clinical manifestations

live attenuated trivalent vaccine (MMR)

In Measles Epidemiology, Introduction of- decreases case

Serlogic assays

NAAT

Measles virus laboratory testing

Blood, Respiratory, Oropharynx, or Conjunctiva

- May also shed in urine.

Measles culture samples

TOGAVIRIDAE

Example of this is Rubella virus

RUBELLA (German Measles) VIRUS

mild febrile rash illness

- Direct or droplet contact

- Risks for nonimmune pregnant mothers

1. Vertical transmission

2. Congenital rubella syndrome(CRS)

Rubella Virus Transmission

Rash, Fever

Rubella symptoms

part of MMR(Measles. Mumps, Rubella)-live attenuated vaccine

Rubella Vaccination:

Serologic assays

NAATs

Rubella Laboratory Diagnosis

Herpesviridae

Example is Varicella-Zoster Virus, Epstein-Barr Virus, Cytomegalovirus

VARICELLA-ZOSTER VIRUS (VZV)

- causes chickenpox

(classic childhood disease w a maculopapular rash)*

Transmission: Respiratory secretions*

VZV Pathogenesis

- Infects conjunctiva or upper respiratory tract mucosa

- spreads to lymph nodes

Primary viremia>T cells enter bloodstream

in VZV

- 4 to 6 days post infection:

Secondary viremia

in VZV

14 days post-infection>skin

infection>vesicular rash

Fever, Malaise

- Maculopapular rash: trunk and scalp

- Lesions:

VZV Symptoms