Any of a group of infectious diseases that interfere with the blood's ability to clot. Hemorrhagic fevers are spread by contact with infected animals, people, or insects. Examples include Ebola and yellow fever. Avoiding mosquitoes and rodents can help prevent infection.

1. Viral Haemorrhagic Fevers
Viruses in Sudan:
@ Yellow fever virus
@ Dengue fever virus
@ Rift Valley fever virus
@ Ebola fever virus
@ Lassa fever virus

2. Ebola Fever Virus
Symptoms:
@ Fever, headache, skin rash
@ Haemorrhage, vomiting, diarrhoea
@ Hepatitis, pharyngitis
@ 50% fatal.
@ Spreads directly from case to case
@ Host of Ebola virus is unknown.

3. Properties:
@ Family Filovirus: RNA viruses
@ Long filamentous with hooked ends.
@ Enveloped, with surface projections
@ Helical capsid, single stranded RNA
@ No antiviral therapy & no vaccination

4. Lab. Diagnosis:
@ Specimen: blood.
@ Inoculate guinea pigs or cell cultures.
@ Look for signs of illness in guinea pigs
@ In cell cultures look for inclusion
bodies by immunofluorescence.
@ Serology by immunofluorescence.

5. Lassa Fever Virus
Symptoms:
@ Fever, sore throat, vomiting, cough.
@ Weakness, ulcers in mouth
@ Facial oedema, diarrhoea
@ Haemorrhage, shock, deafness
@ Symptomless: among rural populations.
@ Infection is by inhalation or ingestion
of contaminated food or by contact
with cases.

6. Properties:
@ Arenavirus family: RNA virus
@ Enveloped, helical, with surface spikes.
@ Single stranded, circular RNA
@ Natural host: small rodents

7. Lab. Diagnosis:
@ Isolation of the virus in cell culture
@ Serology: Antibody detection by
immunofluorescence and ELISA
@ Treatment: By ribavirin .
@ No vaccine is available