Zoonotic agents Flashcards
BSE – bovine spongiform encephalopathy
General
BSE transmission to humans is not efficient
BSE – bovine spongiform encephalopathy
Natural host
cattle
Rocky Mountain Spotted fever ( Rickettsia ricketsii)
General
a
a
a
West Nile virus
General
Family Flaviviridae and the genus Flavivirus
First isolated from a febrile adult woman in the West Nile District of Uganda in 1937.
West Nile virus
Laboratory Safety and Containment Recommendations
May be present in blood, serum, tissues, and CSF of infected humans, birds, mammals, and reptiles. The virus has been found in oral fluids and feces
of birds. Parenteral inoculation with contaminated materials poses the greatest hazard; contact exposure of broken skin is a possible risk. Sharps precautions should be strictly adhered to when handling potentially infectious materials. Workers performing necropsies on infected animals may be at higher risk of infection.
BSL-2 practices, containment equipment, and facilities are recommended
for activities with human diagnostic specimens, although it is unusual to recover virus from specimens obtained from clinically ill patients. BSL-2 is recommended for processing field collected mosquito pools whereas BSL-3 and ABSL-3 practices, containment equipment, and facilities are recommended for all manipulations of WNV cultures and for experimental animal and vector studies, respectively.
Dissection of field collected dead birds for histopathology and culture is recommended at BSL-3 containment due to the potentially high levels of virus found in such samples. Non-invasive procedures performed on dead birds (such as oropharyngeal or cloacal swabs) can be conducted at BSL-2.
Toxoplasma gondii
General
a
a
a
Salmonella spp.
a
a
a
Leishmania spp
a
a
a
Giardia
Intestinal protozoal parasite
a
a
Lyme disease (Borrelia burgdorferi)
a
a
a
Campylobacter spp
a
a
a
Cat scratch fever
Bartonella henelae
a
a
a
E coli O157:H7
a
a
a
Hantavirus
a
a
a
Lymphocytic choriomeningitis
virus (LCVM)
General
Rodent-borne viral infectious disease that presents as aseptic meningitis, encephalitis, or meningoencephalitis.
The virus is the protypical member of the family Arenaviridae.
Lymphocytic choriomeningitis
virus (LCVM)
OCCUPATIONAL INFECTIONS
Most infections occur when chronic viral infection exists in laboratory rodents, especially mice, hamsters and guinea pigs.
Nude and severe combined immune deficient (SCID) mice may pose a special risk of harboring silent chronic infections.
Inadvertently infected cell cultures also represent a potential source of infection
Rabies Virus (and related lyssaviruses) General
Rabies is an acute, progressive, fatal encephalitis caused by negative-stranded RNA viruses in the genus Lyssavirus, family Rhabdoviridae.
Rabies virus is the representative member (type species) of the genus. Members of the group include Australian bat lyssavirus, Duvenhage virus, European bat lyssavirus 1, European bat lyssavirus 2, Lagos bat virus, and Mokola virus.
Rabies Virus (and related lyssaviruses) OCCUPATIONAL INFECTIONS
LAI are extremely rare
Two have been documented. Both resulted from presumed exposure to high concentrations of infectious aerosols, one generated in a vaccine production facility.
Naturally or experimentally infected animals, their tissues, and their excretions are a potential source of exposure for laboratory and animal care personnel.
Histoplasma spp
a
a
a
Cryptosporidium spp
Intestinal protozoal parasite
a
a
Cryptococcus spp
a
a
a
Leptospira spp
a
a
a
Herpesvirus simiae (Cerocopithecine herpesvirus I, herpes B virus) General
Alphaherpesvirus genus (simplexvirus) in the family Herpesviridae.
Macaques may have primary, recurrent, or latent infections often with no apparent symptoms or lesions.
Human infections in at least 50 instances, with approximately 80% mortality when untreated. There remains an approximate 20% mortality in the absence of timely treatment with antiviral agents.
No reported cases in situations where prompt first aid with wound or exposure site cleansing was performed.
Invasion of the central nervous system, resulting in ascending paralysis
Herpesvirus simiae (Cerocopithecine herpesvirus I, herpes B virus)
Occupational infections
Mucosal secretions (saliva, genital secretions, and conjunctival secretions) are the primary body fluids associated with risk of B virus transmission.
Zoonoses have been reported following virus transmission through a bite, scratch, or splash accident.
Cases of B virus have also been reported after exposure to monkey cell cultures and to central nervous system tissue.
Herpesvirus simiae (Cerocopithecine herpesvirus I, herpes B virus) Lab Safety
Virus can be transmitted through bites, scratches, or splashes only when the animal is shedding
Fomites should always be considered sources
Containment Recommendations
BSL-2 practices and facilities are suitable for all activities involving the use or manipulation of tissues, cells, blood, or serum.
BSL-3 practices for handling materials from which B virus is being cultured
BSL-4 facilities are recommended for propagation of virus obtained from diagnostic samples or stocks. Experimental infections of macaques as well as small animal models with B virus are recommended to be restricted to BSL-4 containment.
Barrier is required to prevent droplet splashes
Herpesvirus simiae (Cerocopithecine herpesvirus I, herpes B virus)
NATURAL MODES OF INFECTION
10% of newly caught rhesus monkeys have antibodies
Frequently present in kidney cell cultures.
Vesicular lesions on the tongue and lips, and sometimes of the skin.
Increase when macaques reach sexual maturity.
Herpesvirus simiae (Cerocopithecine herpesvirus I, herpes B virus)
Reservoir species
Macaca mulatta, M. fascicularis, M.fusata, M. arctoides, M.cyclopsis and M. radiata.
West Nile virus
Natural Modes of Infections
Culex genus mosquitoes transmit WNV.
Virus amplification during periods of adult mosquito blood-feeding by continuous transmission between mosquito vectors and bird reservoir hosts.
West Nile virus
Occupational Infections
SALS reported 15 human infections from laboratory accidents in 1980.
One attributed to aerosol exposure. Two parenteral inoculations during work with animals.
Japanese encephalitis virus antigenic complex
examples
The complex currently includes Alfuy, Cacipacore, Japanese encephalitis, Koutango, Kunjin, Murray Valley encephalitis, St. Louis encephalitis, Rocio, Stratford, Usutu, West Nile, and Yaounde viruses.
Bovine spongiform encephalopathy
MECHANISM OF PATHOGENESIS
Infection with prion-contaminated feedstuffs
BSE – bovine spongiform encephalopathy
Lab Safety
Minimum in a BSL-2 facility.
Necropsies on large animals if opportunity that the worker may be accidentally splashed or have contact with high-risk materials (e.g., spinal column, brain, etc.) should wear full body coverage PPE (e.g., gloves, rear closing gown and face shield).
Disposable plasticware, which can be discarded as a dry regulated medical waste, is highly recommended.
Because the paraformaldehyde vaporization procedure does not diminish prion titers, BSCs must be decontaminated with 1N NaOH and rinsed with water.
Although there is no evidence to suggest that aerosol transmission occurs in the natural disease, it is prudent to avoid the generation of aerosols or droplets during the manipulation of tissues or fluids and during the necropsy of experimental animals. Impervious gloves worn for activities that provide the opportunity for skin contact with infectious tissues and fluids.
Animal carcasses and other tissue waste can be disposed by incineration with a minimum secondary temperature of 1000oC (1832oF). Pathological incinerators should maintain a primary chamber temperature in compliance with design and applicable state regulations, and employ good combustion practices.
The alkaline hydrolysis process, using a pressurized vessel that exposes the carcass or tissues to 1 N NaOH or KOH heated to 150oC, can be used as an alternative to incineration for the disposal of carcasses and tissue.
The process has been shown to completely inactive TSEs (301v agent used) when used for the recommended period of time.
Rabies Virus (and related lyssaviruses) NATURAL MODES OF INFECTION
The natural hosts of rabies are many bat species and terrestrial carnivores, but most mammals can be infected.
The saliva of infected animals is highly infectious, and bites are the usual means of transmission, although infection through superficial skin lesions or mucosa is possible.
Rabies Virus (and related lyssaviruses) LABORATORY SAFETY (not containment)
Highest viral concentrations are present in (CNS) tissue, salivary glands, and saliva.
Accidental parenteral inoculation, bites by infected animals, and exposure of mucous membranes or broken skin, are the most likely sources for exposure.
Rabies Virus (and related lyssaviruses) Containment Recommendations
BSL-2 and/or ABSL-2 practices
Pre-exposure rabies vaccination
Prompt administration of postexposure booster vaccinations.
Additional primary containment and personnel precautions, such as those described for BSL-3, are indicated for activities with a high potential for droplet or aerosol production, and for activities involving large production quantities or high concentrations of infectious materials.
What is the most prevalent pulmonary mycotic infection in man?
Histoplasma capsulatum
Lymphocytic choriomeningitis
virus (LCVM)
Seroprevalence
LCM and milder LCMV infections have been reported in Europe, the Americas, Australia, and Japan, and may occur wherever infected rodent hosts of the virus are found. Several serologic studies conducted in urban areas have shown that the prevalence of LCMV infection among humans ranges from 2% to 10%. Seroprevalence of 37.5% has been reported in humans in the Slovak Republic.
Lymphocytic choriomeningitis
virus (LCVM)
LABORATORY SAFETY
Parenteral inoculation, inhalation, contamination of mucous membranes or broken skin with infectious tissues or fluids from infected animals are common hazards.
Aerosol transmission is well documented.
Tumors may acquire LCMV as an adventitious virus.
Virus may survive freezing and storage in liquid nitrogen for long periods.
Lymphocytic choriomeningitis
virus (LCVM)
pregnant women
Pregnant women infected with LCMV have transmitted the virus to their fetus with death or serious central nervous system malformation as a
consequence.
Lymphocytic choriomeningitis
virus (LCVM)
where is it in infected animals?
May be present in blood, CSF, urine, secretions of the nasopharynx, feces and tissues of infected animal hosts and humans.
Lymphocytic choriomeningitis
virus (LCVM)
Containment Recommendations
BSL-2 is suitable for activities utilizing known or potentially infectious body fluids, and for cell culture passage of laboratory-adapted strains.
BSL-3 is required for activities with high potential for aerosol production, work with production quantities or high concentrations of infectious materials, and for manipulation of infected transplantable tumors, field isolates and clinical materials from human cases. Strains of LCMV that are shown to be lethal in non¬human primates should be handled at BSL-3.
ABSL-2 for studies in mice with strains requiring BSL-2
Work with infected hamsters should be done at ABSL-3.
