Zoonoses 4th year 5-3-2017 Dr.Osama muwafg
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Argentine Hemorrhagic Fever (AHF)
Agent
Junin virus; RNA virus, genus Arenavirus, family Arenaviridae
RECOGNITION
Syndrome:
Human:
1. Gradual onset of fever, malaise, headache,
2. muscular and back aches,
3. retro-orbital pain
4. conjunctival congestion
5. gastrointestinal signs.
6. Petechiae appear on the skin and palate, and axillary and
inguinal lymphadenopathies develop.
7. CNS signs, hypotension, and bradycardia develop on about
day 4,
8. hemorrhagic manifestations appear several days later.
9. Bleeding gums and epistaxis are most common, although in
severe cases hematemesis, melena, hemoptysis, or hematuria
may occur.
10. Usually, rapid improvement occurs after the second week and
recovery is complete in 1-3 months.
11. However, profuse hemorrhages, pronounced neurologic
signs, and shock may appear 8-12 days after onset of fever,
and most of these cases are fatal.
12. Superimposed bacterial infections also contribute to
mortality.
Zoonoses 4th year 5-3-2017 Dr.Osama muwafg
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Animal:
Field rodents with subclinical infections are reservoirs.
Incubation period: 6-16 days.
Case fatality rate: 10%-30%.
Confirmatory tests:
1. Virus isolation requires several weeks.
2. Immunohistochemical techniques (e.g., immunoperoxidase
staining of cell culture) can detect viral antigen within a few
days.
3. Serologic tests are CF, SN, IFA, and ELISA.
Occurrence:
Widespread throughout the Argentine pampas, with most cases
occurring in a large area west-southwest of Uruguay.
Outbreaks occur annually, and the area where they are recognized
is expanding.
Male agricultural workers are most often affected.
Transmission:
1. Virus in excreta from rodents
2. most likely transmitted to humans via aerosols, contaminated
food or water, or directly inoculated into broken skin.
3. Although interhuman transmission may occur, it is not
regarded as contagious
Control And Prevention
Zoonoses 4th year 5-3-2017 Dr.Osama muwafg
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1. Individual/herd: Immune plasma is effective in treating
severe cases.
2. A live attenuated vaccine is available.
3. When caring for patients, general hygienic precautions are
sufficient to prevent inter human transmission.
Local/community:
None Field rodent hosts do not frequent human habitation.
National/international: None.
Crimean-Congo Hemorrhagic Fever (CCHF)
Agent
RNA virus, genus Nuirovirus (group CON), family Bunyaviridae
RECOGNITION
Syndrome:
Human:
1. Typically, sudden onset, with high fever and chills,
headache,
dizziness, and myalgia.
2. Gastrointestinal signs, such as abdominal pain, nausea,
vomiting, and diarrhea, are commonly seen, as is
bradycardia.
3. The face and neck may be flushed, and the conjunctivae
congested.
4. Fever lasts 5-12 days, with hemorrhage beginning about day
4.
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5. Bleeding from the nose, gums, kidneys, and gastric mucosa
are the most frequent manifestations, and petechiae in the
mouth and skin may also be seen.
6. Death usually results from hock caused by blood loss, or
from neurologic complications or pulmonary hemorrhage.
7. The hemorrhagic phase continues for some 10-15 days.
8. Patients who survive experience extreme weakness,
sweating, headache, and malaise; vision and hearing
impairment, loss of memory, and respiratory dysfunction
may also occur.
9. Sequelae are not permanent, but may persist for a year or
more.
10. Less severe illnesses, with only mild fever and no
hemorrhaging, may outnumber the hemorrhagic cases, and
subclinical infections occur.
Animal: Subclinical viremia in cattle and sheep
Incubation period: 3-7 days.
Case fatality rate: 2%-50%.
Confirmatory tests:
1. Virus isolation from acutely ill patients or from autopsy
specimens,
2. various serologic tests (e.g., ELISA).
Occurrence:
1. Usually sporadic cases scattered throughout Eurasia and
Africa,
2. generally from June to September, the period of maximal
vector activity.
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3. The virus has been isolated from southern Europe, central
Asia, the Middle East, and much of Africa,
4. but antibodies in humans and animals indicate an even wider
distribution.
5. Most human cases occur in rural areas among farmers or
livestock handlers, or among medical personnel
Transmission:
1. Tickborne. Hares, hedgehogs, bats, and birds are the probable
vertebrate reservoirs;
2. ticks of the genus Hyalomma are arthropod reservoirs
CONTROL AND PREVENTION
Individual/herd :
1. An inactivated vaccine is available
2. Avoid tick-infested areas whenever possible
3. When necessary to enter areas known to harbor ticks,
protective clothing should be worn and chemical repellents
used, and the body should be inspected every 3-4 hours.
4. Any material contaminated with blood should be handled
very carefully and disposed of by incineration or sterilized
before washing
Local/community:
1. Although vector populations may be reduced by use of
acaricides and host management, these means may be
impractical.
2. Public education regarding hazards of tick bite and means
of personal protection.