Animal infection testing of pathogenic microorganisms are an important risk prevention point for biological safety accidents. Pathogens carried by infected animals can infect experimental workers through air aerosols, secretions, and excrement during the operation.
The operation of animal infection involves animal anesthesia, drug administration, sample collection, euthanasia, and necropsy. The chicken embryo experiment can also be attributed to the operation of infected animals, which can cause various accidents. This article will explain the types of accidents, emergency plans, accident site operations and accident prevention one by one.
1. Types of accidents in animal Lab
1.1 Stabbing or cutting wounds Stabbing wounds often occur in the process of anesthesia, drug administration, sampling, and chicken embryo inoculation. Incision injuries often occur during surgery, anatomy, etc.
1.2 Scratch bites Scratch bites often occur during the process of litter replacement, anesthesia, temperature measurement, etc.
1.3 Animal escape often occurs during anesthesia and litter replacement.
1.4 Overdose of anesthesia Overdose of anesthesia in medium and large animals is considered an accident.
1.5 Unexpected chicken embryo experiment
· Stabbing when inoculating chicken embryos
· Spills when collecting viruses
· Dropping while transporting chicken embryos
2. Emergency plan for accidents in animal lab
2.1 In response to possible infectious animal experiment accidents, in order to ensure the safe and stable operation of the biosafety laboratory, an effective accident handling plan should be formulated.
2.2 The principle of the disposal procedure in the event of an accident is to protect the health and safety of the staff and minimize the pollution of the laboratory environment and the external environment.
2.3 The principle of taking measures is to control proliferation, control the source of infection, and safely dispose of contaminated materials and contaminated places.
2.4 The emergency plan should include (not limited to): person in charge, organization, emergency communications, report content, personal protection and response procedures, emergency equipment, evacuation plans and routes, isolation and disinfection of pollution sources, personnel isolation and treatment, on-site isolation and Control, risk communication, etc.
2.5 The laboratory should train all personnel (including visitors) to be familiar with emergency procedures, evacuation routes and evacuation assembly locations; conduct at least one drill per year
3.Key points of on-site handling of accidents in animal Lab
When an animal accident occurs in the laboratory, on-site disposal is very important, and detailed handling will greatly reduce the risk of laboratory contamination and personnel infection. At the same time, it is equipped with necessary first-aid equipment and equipment for on-site treatment and use. The location of the first-aid kit: should be placed in the protective area. Composition (including but not limited to): 75% ethanol, iodophor, band-aid, gauze, bandage, scissors/ Tweezers, medical tape, etc.
01) On-site treatment of needle stick injuries/cutting injuries and scratches and bites
① Stop the experiment immediately and place the experimental animals in a sealed cage.
② Another experimenter sprayed 75% ethanol on the injured person and took off his gloves (in the biological safety cabinet)
③ Squeeze the part with your hands to make the blood flow out, and wash the wound with clean water or water from an eyewash.
④ Take out the first aid kit and wipe the contaminated skin and wound with iodophor or appropriate disinfectant several times.
⑤ Dress up the wound properly, wear clean gloves, and evacuate and exit the laboratory according to the prescribed route
⑥ Accident report
⑦ Medical evaluation/designated hospital treatment/isolation, etc.
The focus of on-site handling of this type of accident:
① Control animals
② Clean up the wound
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02) On-site treatment of animal escape
① Stop the experiment immediately and carry out hunting. In principle, personnel shall not leave the animal laboratory before catching the escaped animal.
② If a small rodent escapes to the laboratory, immediately use long-handled tweezers to quickly and firmly clamp the root of the tail to grab the animal and place it in the cage. If the animal escapes quickly and is not easy to grasp with tweezers, use a special net bag to grasp it. If the animal escapes to a place under the equipment that is not easy to grasp, use the net bag handle (the net bag can be split into a handle and a net bag) to carefully drive the animal out of the equipment before grabbing.
③ Increase the frequency of indoor ventilation, cover the escape route of the animal and the blood and secretions splashed by the animal with a wet disinfectant cloth or paper towel for 30 minutes, then place it in the specified container for autoclaving; and report to the person on duty Organize a second decontamination.
The focus of on-site handling of this type of accident:
① Escape of rodents occurs more often, and the capture should be confined to the laboratory. Don’t panic and grab multiple times. Minimize irritation to animals.
② In principle, escaping animals must not leave the laboratory before being culled, so as to prevent the animals from escaping from the laboratory into the public area and causing greater public health incidents.
03) On-site treatment of anesthesia overdose
Signs of anesthesia overdose
Mild: Refers to experimental animals that have significantly slowed down their breathing rate and have mild hypoxia, such as their tongue turning from bright red to dark, but they still breathe regularly. The breathing depth is normal, and the circulatory system has no obvious obstacles. Blood pressure and heartbeat are normal.
Severe: Respiratory frequency drops drastically and irregularly, sometimes not, and suddenly deep and shallow, obvious hypoxia, such as a purple tongue, the oxygen partial pressure and oxygen saturation in the blood test are significantly reduced, and the circulatory system is affected , If the heartbeat slows down, blood pressure drops. However, corneal reflexes exist.
Critical: respiratory arrest, slow and irregular heartbeat, drop in blood pressure, or cardiac arrest.
Approach
① When breathing is extremely slow and irregular, but the heartbeat is normal: give artificial respiration-chest compression, and give appropriate rejuvenation agents.
② When breathing is stopped and there is still heartbeat: ① Perform artificial respiration, use artificial ventilator or oxygen if necessary (inhalation of O2 accounts for 95%, CO2 accounts for 5%); ② Inject 50% glucose solution; ③ Give adrenaline and Rejuvenating agent. Use 5% sodium bicarbonate intravenously to correct acidosis.
③ When breathing and heartbeat stop: Intracardiac injection of 1:10000 adrenaline solution. The respiratory stimulant 25% Nixamir is injected intravenously or intracardiac. An injection of 20 mg/mL dopamine increases blood pressure. Use 5% sodium bicarbonate intravenously to correct acidosis.
The focus of on-site handling of this type of accident:
① Medium and large animals are prone to anesthesia overdose.
② Prevent scratches and bites during first aid during anesthesia overdose.
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04) Handling of accidents in chicken embryo experiment
Stabbing during inoculation of chicken embryos-the treatment is the same as 1 “stab wound treatment”
Spills during virus collection-treatment is the same as “spills of infectious substances”
Handling of dropping when transporting chicken embryos
① Cover the drop area with absorbent paper, pour the disinfectant containing 1% available chlorine from the outside to the inside, wrap the eggshell and egg yolk and other solids, collect them with tweezers and place them in the specified container for autoclaving; and report to the person on duty Organize a second decontamination.
② Pour with disinfectant within 1 meter radius of the falling area and act for 30 minutes.
③ After spraying disinfectant all over, the experimenter exits according to the prescribed route
④ Report the on-duty personnel to clean up the laboratory a second time.
The focus of on-site handling of this type of accident:
① The egg yolk is classified as a solid substance and needs to be collected under high pressure
② Allantoic fluid is viscous and it takes longer to disinfect than normal fluids.
③ The choice of disinfectant depends on the pathogen being operated. Chlorine disinfectant is a general disinfectant.
4. Prevention of accidents in animal Lab
01) Needle sticks, cuts, scratches and bites
① Wear protective gloves: anti-bite gloves/anti-cut gloves
② Use a suitable holder
③ Operate after the animal is fully anesthetized.
02) Animal escape
① Operate after the animal is fully anesthetized
② Participate in animal Baoding technical training
③ Operation in the biological safety cabinet
④ Make sure that the cage is covered and put it back into the cage holder; primates need to be equipped with appropriate cage locks.
03) Anesthesia overdose
① Use anesthetics
② Small amount of divided administration
a) The animal’s body temperature is easy to drop during the anesthesia period, and insulation measures should be taken.
b) The intravenous injection must be slow. At the same time, observe the muscle tension, corneal reflex and response to skin pinching. When these activities are significantly weakened or disappeared, the injection should be stopped immediately. When doing chronic experiments, in the cold winter, the anesthetic should be heated to the animal’s body temperature before injection.
③ Equipped with anesthetic first aid: cardiotonic, respiratory stimulant, sodium bicarbonate (used to correct acidosis), hypertonic glucose (used to raise blood pressure), etc.
04) Chicken embryo experiment
The embryo transfer uses a shipping container. Chicken embryos inoculated with microorganisms should be transported in the laboratory with double-layer hard, unbreakable, high-pressure resistant packaging to prevent splashing and spilling when falling, and to confine the pathogenic microorganisms in the packaging container for subsequent disinfection and sterilization.