viral infection of RBCs Flashcards
(23 cards)
illustrate Pathogenesis of VHFs (viral hemorrhagic fever)
- Virus at site of entry → local LNs → multiplies → blood → viremia → liver, spleen, kidney, BM, LNs
- vascular permeability
- DIC
- Hepatic involvement
- Hypotension
- Multisystem organ failure
- Shock, circulatory collapse & death.
African Hemorrhagic Fevers =…………&………….
Marburg & Ebola HFs
what’s African Hemorrhagic Fevers?
Severe & highly fatal diseases caused by viruses, from the Filoviridae family
ss RNA, enveloped, -ve sense.
about MARBURG & EBOLA HFs
1. Among the ………….pathogens known to infect humans
2. Both are clinically almost …………
3. are, but may cause dramatic outbreaks with high …….
- most virulent
- indistinguishable
- fatality
about Reservoir & MOT of MARBURG & EBOLA HFs :
- Highly ………..
- Transmitted to man ………..
- ………… may be the reservoir
- ………… are susceptible to infection but are Not considered viable reservoir hosts
- MOT: ………………
mainly by: ……………. - Fatality:
* Ebola up to……… & Marburg up to…..
- communicable
- accidentally
- Bats
- Monkeys
- Person to Person transmission
by: intimate contact
(Direct contact with infected blood, secretions, organs or other body fluids of infected persons) - Ebola up to 50% & Marburg up to 25%
what’s the laboratory diagnosis of MARBURG & EBOLA HFs ?
Laboratory Diagnosis
* Based on Symptoms
* Demonstration of filoviruses in blood:
ELISA & PCR
illustrate both treatment &prevention of MARBURG & EBOLA HFs
Treatment
* Supportive care involves fluid & electrolytes, sometimes anticoagulants
* No antiviral drug
Prevention
* Vaccine have been developed that protect monkeys
enumerate other viruses that may be presented by hemorrhage
- Flaviviruses:
Yellow Fever & Dengue Fever - Bunya viruses:
Rift Valley Fever & Hantavirus associated syndromes. - Arenaviruses:
The most significant is Lassa Fever virus
enumerate other viruses that may be presented by hemorrhage
- Flaviviruses:
Yellow Fever & Dengue Fever - Bunya viruses:
Rift Valley Fever & Hantavirus associated syndromes. - Arenaviruses:
The most significant is Lassa Fever virus
about Yellow Fever
1. It is an acute, febrile, mosquito-borne illness that occurs in Africa & USA
* It is caused by………………
- Yellow fever virus.
(About yellow fever)
-Reservoir & MOT:
Two major epidemiologic cycles of
transmission of yellow fever:
1……
2……
1.Jungle YF
2.Urban YF
according to Jungle YF:
1. Primarily a disease of …………
2. Monkey-to-monkey by……….
3.Man is ………. on visiting the jungle
- monkeys
- forest Aedes mosquito
- accidentally infected
according to Urban YF:
1. Person-to-person by ………
2. When an infected person from the …… returns to …….
1.domestic Aedes mosquito
(Aedes aegypti)
2. jungle/urban areas
illustrate Clinical manifestations of yellow fever
- Mild or so severe & fatal.
- Fever, headache, dizziness, myalgia &
backache followed by recovery or may develop jaundice (hence yellow fever) & renal dysfunction. - In severe cases, hemorrhagic manifestations appear. Patients have black vomitus with high mortality rate (20% or more).
illustrate Lab diagnosis of yellow fever.
Detection of:
* viral antigens in the blood by ELISA
* Viral nucleic acid detection by PCR
illustrate Treatment & prevention of yellow fever
-Treatment
* Supportive, depends on system affected.
- Prevention
1.Mosquito control .
2.Vaccine (17D vaccine) : - live attenuated.
- to travelers & residents of endemic areas.
- Single SC dose → immunity for 10 years
about Dengue fever
1.DF & DHF are caused by one of …. closely related, but………….., DF virus serotypes …………..
- Infection with one serotype provides
immunity to ……….
3.so persons living in a dengue endemic area can have……… during their lifetime
- ………. is the reservoir host.
- Person-to-person transmission
occurs by ……….
1.
- four
- antigenically distinct
- (DEN-1, 2, 3 & 4)
- only that serotype for life
- more than one dengue infection
- Man
- domestic Aedes mosquito
(Aedes aegypti)
discuss the clinical manifestations of dengue fever
- Classical DF:
-high fever, headache, sever myalgia & arthralgia
- maculopapular rash - Dengue HF:
- A potentially deadly complication of dengue.
- It appears to be an immuno-pathological consequence (?) 2ry infection with a different virus serotype - Dengue shock syndrome DSS:
- Skin hemorrhages such as petechiae & purpura.
- Most patients develop thrombocytopenia & hemoconcentration.
- If not immediately corrected → profound shock
& death
discuss the following with dengue fever:
1.Diagnosis
2.Prevention
3.Treatment
1.Diagnosis
* Antigen detection in blood
2.Prevention
* Mosquito control is the most important strategy
3.Treatment
No specific treatment is available
Bunya viruses
- Rift Valley Fever (RVF) is …………..
A mosquito-borne zoonotic disease
illustrate Reservoir & MOT of rift valley fever
- Pathogenic 1rly for sheep, cattle, buffaloes, goats & camels → hepatitis, abortion & death
- Humans are 2ndly infected during the course of epizootics in domestic animals by bite of an infected mosquito
- exposure to blood or other body fluids of infected animals
illustrate Clinical Pathology of RVF
- Mostly asymptomatic or flu-like illness
with complete recovery. - A small proportion of patients may develop:
-retinitis with visual loss
-meningoencephalitis - hemorrhagic fever.
discuss Prevention of RVF
sustained program of animal vaccination
(Live attenuated & killed)
