|
SECTION I - INFECTIOUS AGENT
NAME: Colorado tick fever virus
SYNONYM OR CROSS REFERENCE: Tick-borne fever, arbovirus
CHARACTERISTICS: Reoviridae, coltivirus, 65-70mn diameter, ds RNA (Note change from single to double strand
RNA)
SECTION II - HEALTH HAZARD
PATHOGENICITY: Acute febrile, often diphasic, dengue-like disease with infrequent rash; brief remission
followed by second bout of fever lasting 2-3 days; neutropenia, thrombocytopenia; occasional encephalitis, myocarditis,
or tendency to bleed; deaths are rare.
EPIDEMIOLOGY: Western North America; most frequent in adult males, but also affects children and women;
seasonal incidence parallels the period of greatest tick activity; endemic in occurrence and common in affected
area.
HOST RANGE: Humans, small mammals.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: By bite of an infective vector tick; immature ticks acquire infection by feeding on
infected viremic animals; ticks remain infected through the various molts and transmit virus to man by feeding
as adult ticks.
INCUBATION PERIOD: Usually 4-5 days.
COMMUNICABILITY: Not directly transmitted from person to person, except by transfusion; ticks remain infective
for life; virus is present in humans during the course of fever, from 2-16 weeks or more after onset.
SECTION III - DISSEMINATION
RESERVOIR: Small mammals, ground squirrels, chipmunk, porcupine.
ZOONOSIS: Yes, through bite of an infected tick.
VECTORS: Tick - Dermacentor andersoni.
SECTION IV - VIABILITY
DRUG SUSCEPTIBILITY: N/A
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite (20% commercial beach), 70% ethanol,
glutaraldehyde, formaldehyde.
PHYSICAL INACTIVATION: Inactivated by heat (50-60o C for at least 30 min.).
SURVIVAL OUTSIDE HOST: Does not survive out of host.
SECTION V - MEDICAL
SURVEILLANCE: Serological studies or isolation of virus from blood.
FIRST AID/TREATMENT: No specific treatment.
IMMUNIZATION: None available.
PROPHYLAXIS: None available.
SECTION VI - LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: 16 reported laboratory acquired infections.
SOURCES/SPECIMENS: Blood, CSF, other tissues; arthropods, depending on the stage of infection.
PRIMARY HAZARDS: Accidental parenteral inoculation, contact of the virus with broken skin or mucous membranes,
bites of infected laboratory rodents or arthropods; infectious aerosols may also be a potential source of infection.
SPECIAL HAZARDS: None
SECTION VII - RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices, safety equipment and facilities are recommended
for activities with potentially infectious clinical materials and arthropods and for manipulations of infected
tissue cultures, embryonated eggs, and rodents.
PROTECTIVE CLOTHING: Laboratory coat; gloves and gown when working with infectious materials.
OTHER PRECAUTIONS: None
SECTION VIII - HANDLING INFORMATION
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towel and
apply 1% sodium hypochlorite (20% commercial bleach), starting at perimeter and working towards the center- allow
sufficient contact time before clean up (30 min).
DISPOSAL: Decontaminate before disposal; steam sterilization, incineration.
STORAGE: In sealed containers that are appropriately labeled.
Date prepared: September 1996 Prepared by: Canadian Office of Biosafety.
Information edited by the Colorado State University Office of Biosafety; June 16, 1998.
|