A. Bites and Scratches
Bites and scratches represent a significant portion of laboratory animal associated hazards. These injuries are readily preventable through proper animal handling technique and the use of proper PPE. You should always wear a long sleeve lab coat or use other sleeve protection (e.g., Tyvek® sleeves) when handling rabbits or larger animals to avoid scratch injury, and in some cases special gloves (e.g., stainless steel mesh or heavy leather gauntlets) to prevent bites. Prior to animal handling, eliminate unusual noises, defective equipment, slippery surfaces and conditions conducive to entrapment or distraction of the animal handler. Inappropriate animal handling may induce discomfort, pain, and distress in the animal. This can provoke a fractious response, introduce undesirable experimental variables, and provide an opportunity for the animal to inflict injury upon the handler. OACU Training and Compliance personnel can provide supervised instruction for those undertaking new animal-handling procedures in addition to their regularly scheduled training courses.
Special attention and training is necessary if you are involved in the handling and restraint of large animals, especially non-human primates. In addition to posing a bite and scratch hazard, non-human primates can be challenging and difficult to handle safely because of their remarkable strength, dexterity, intelligence, and tenacity. Non-human primates have caused injuries when they have grabbed and pulled neckties, loose-fitting lab coats, or long hair of unsuspecting personnel. When compatible with the experimental conditions of animal use and/or the clinical condition of the animal, consider chemical immobilization of many non-human primate species to enable safe animal handling and to reduce the risk of injury.
DLAM posts specific PPE requirements in the housing areas for working with macaque monkeys. These requirements include the DLAM outerwear mentioned earlier, plus safety (splash) goggles; a face shield is also required for close contact with conscious animals. During the quarantine period, before the monkeys are known to be free from tuberculosis, you must use a NIOSH certified, fitted N95 respirator at a minimum. Refer to Chapter 5 for more details about respiratory protection.
Animal bites continue to be a common occurrence among research personnel, and you should take them seriously even when there is little tissue damage. If a laboratory animal bites you, seek prompt medical review of the wound and tetanus immunization status by UEOHC. Complete the employee accident form, Form 19, and supervisor form. If warranted, the animal will receive a veterinary evaluation.
Animal bites also prompt a veterinary review of the animal handling circumstances to ensure that you used proper animal handling techniques. A specific, detailed protocol is in effect for bites, scratches, or mucous membrane exposures involving some monkey species due to the Herpes B virus, an agent that can cause fatal infection. Other specific viral agents that can be involved as wound contaminants include rabies virus (all mammals), Hantavirus (rodents), lymphocytic choriomeningitis virus (rodents) and orf virus (sheep and goats). Numerous bacterial agents and at least one fungal agent have also been recorded as wound contaminants resulting in serious localized or systemic infections.
B. Animal Associated Allergy
An estimated 10 to 30 percent of individuals who work with laboratory animals may eventually develop an allergy to laboratory animals, which is manifested by reddened, itchy eyes, nasal symptoms, and skin rashes. Individuals with pre-existing allergy to other agents have a predisposition to develop an additional sensitivity to animal allergens. Asthma, characterized by cough, wheezing, chest tightness and shortness of breath, develops as a further complication in approximately ten percent (10%) of individuals with animal-associated allergy. Anaphylaxis, a generalized allergic reaction presenting as diffuse itching, hives, and facial and oral swelling, can develop. Anaphylaxis can produce life-threatening consequences from laryngeal edema, airway obstruction, and shock in certain individuals with massive allergen exposure, often through saliva.
Although rodents, rabbits, and cats are most often incriminated in cases of laboratory animal-associated allergy, other mammals and birds also can be involved. Work practices that minimize contact with animal proteins reduce risk for development of allergy. For example, various levels of PPE are available for personnel working with laboratory animals to reduce exposure to allergen. You should wear long sleeve outer garments (e.g., lab coat or disposable coverall) to reduce the exposure of skin to urine, dander, and other allergens. Filtering facepiece respirators may help reduce the exposure of the respiratory tract to allergen; however, personnel with known inhalant allergy should consider the use of a full-face respirator or a powered-air purifying respirator (PAPR), both of which provide ocular as well as respiratory protection.
Allergy history is an important element of the health review conducted by UEOHC for personnel involved with laboratory animal care and use. If you have or suspect that you are developing an animal-associated allergy, consult with the UEOHC to determine the optimal allergy management strategy. Training is available on the EHS website that outlines Lab Animal Allergies.
Zoonoses are diseases that are transmissible from animals to humans. Laboratory animal species potentially harbor numerous zoonotic agents, including viruses, bacteria, fungi, protozoa and internal and external parasites, but the reported cases of zoonotic transmission to individuals with laboratory animal contact have been infrequent and sporadic. However, many zoonotic disease episodes likely have remained unreported, and those reported involved serious disease and even fatalities. For these reasons, individuals with laboratory animal contact should be aware of these diseases and take appropriate precautionary measures. Training is available on the EHS website that outlines Zoonoses. The likelihood of encountering zoonoses varies with the species of laboratory animal, its source, and history of veterinary care. Consult with the UEOHC staff if you become ill and/or feel you have contracted a disease from a laboratory animal. The following pages give examples of major zoonoses.
1. Rodents and Rabbits
The modern conditions of production and care for most laboratory rodents and rabbits have led to the eradication of zoonoses in most of these species. Although contamination of these animals through environmental sources, contact with wild rodents or other infected animals, or through tumors, cell lines, or other biologics used experimentally happens, it is rare. In most circumstances, only wild-caught, laboratory maintained rodents are a high risk for the transmission of zoonotic diseases. Be familiar with several zoonoses associated with rodents and rabbits.
Two serious systemic viral zoonoses have been associated with the use of laboratory rodents. Lymphocytic choriomeningitis virus causes a flu-like disease with neurological complications, and Hantavirus infection produces a disease marked by renal failure and respiratory complications. Other than the bite-associated bacterial infections from rodents (e.g., rat-bite fever) there are few bacterial zoonoses in these species. The rabbit is a potential source for human bacterial pathogens, especially those that cause human diarrheal disease such as salmonellosis.
Rodents and rabbits are also a source for human ringworm infection, usually recognized as a reddened, annular lesion of the skin of the affected individual. A similar focal dermatitis results from infestation with rabbit fur mite and, rarely, other mite species of rodents. The dwarf tapeworm infestation of rodents also is capable of infecting man. The complete absence or extremely low incidence of these agents in laboratory animal populations has obviated our need to adopt intensive health surveillance measures for individuals who work with these species. However, all personnel should use appropriate PPE when working with these species and report unusual illnesses or conditions possibly related to animal contact. The minimal personnel protective equipment recommended for working with small rodents includes particle facemask, latex (or nitrile or other) disposable gloves, safety glasses and a clean lab coat.
2. Dogs and Cats
Source control and sound programs of veterinary care at the vendors’ facilities and at UNC-CH ensure the eradication of most zoonotic infections in these animal species prior to their experimental utilization. Due to financial limitations, it is not practical to rule out all potential zoonoses. In some cases, subclinical infections may go undetected and untreated, posing a risk for the personnel who work with these animals. These can include intestinal bacterial infections (salmonellosis, yersiniosis, and campylobacterosis), systemic bacterial infections (brucellosis, cat-scratch fever, leptospirosis and Q-fever) and intestinal parasitic infections (giardiasis and toxoplasmosis). The dog and cat can also harbor dermatophytes that cause human ringworm and other external parasites capable of infesting humans.
Proper use of PPE can minimize exposure to these zoonotic hazards, and should include long pants (or similar leg protection), lab coat or coverall, facemask, safety glasses and disposable gloves. If you work with laboratory cats not specifically bred for research purposes, consider participation in the rabies vaccination program available through UEOHC.
3. Non-human Primates
The list of zoonotic diseases in non-human primates is long and includes numerous viral (e.g., Herpes B virus, hepatitis A and B, measles and SIV), bacterial (e.g., tuberculosis, salmonellosis, and shigellosis) and protozoal (e.g., giardiasis and amebiasis) diseases, and there are many documented cases of zoonotic transmission. Consequently, non-human primates must undergo an extensive quarantine period to preclude the presence of many of these zoonoses before experimental work with these animals can proceed. Even after release from quarantine, rigorous disease surveillance continues for some agents such as tuberculosis. Personnel must participate in periodic tuberculin testing through UEOHC if they have any non-human primate contact. Personnel who work with macaques must undergo special training concerning the prevention and management of potential exposure to B virus, an agent that has caused many fatalities among laboratory personnel.
University policies expect strict adherence in the use of PPE by all personnel with non-human primate contact. Personnel handling non-macaque monkey species must wear a lab coat (or equivalent), particle face mask, eye protection, disposable gloves and shoe covers when entering housing areas. The more stringent PPE requirements for personnel using macaque monkeys are in the section on Bites and Scratches.
4. Birds and Livestock
Q fever has proven to be an important zoonosis associated with livestock in laboratory animal facilities. Although all ruminants and many other animals are potential carriers, infection of laboratory personnel has most often been associated with pregnant sheep that copiously shed the organisms. The disease causes a flu-like illness, which can progress to a serious systemic infection with heart involvement. Orf, a pox viral disease of sheep and goats, can also infect humans through contaminated wounds producing firm, nodular lesions. Livestock and birds can harbor bacterial zoonoses causing diarrhea in humans. Birds also can shed the agent psittacosis (Chlamydia psittaci), a serious respiratory and systemic disease of humans. Proper use of PPE is essential to minimize exposure to these potential zoonotic hazards. Use respiratory protection compatible with that described for the prevention of tuberculosis when working with pregnant ruminants (Q fever) or birds harboring Chlamydia psittaci.
A more recent, emerging concern is avian influenza virus, with H5:N1 virus receiving the most attention. H5:N1 virus is an influenza A virus subtype that occurs mainly in poultry and wild birds, is highly contagious among birds, and can be deadly to them. H5:N1 does not usually infect people, but infections with these viruses have occurred in humans. Most of these cases have not resulted from person-to-person contact, but instead resulted from people having direct or close contact with H5:N1-infected poultry or H5:N1-contaminated surfaces. Therefore, proper handling, sanitation, and use of PPE can prevent transmission of virus from bird to human.