Laboratory Animal Diseases and Research Methods

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Questions and Answers

What is the primary cause of ischemic necrosis in tissue, leading to an infarct?

Blockage of blood flow either through arteries or veins.

Define the three zones of infarction mentioned in the text.

Anemia, hemorrhage, and inflammation.

What are the primary purposes of using laboratory animals in research?

Research, education, quality control, and vaccine production.

What types of infectious agents can be associated with the diseases of laboratory animals?

Parasites, bacteria, viruses, and neoplastic agents. Signup and view all the answers

Explain the significance of monitoring health in laboratory animal colonies.

It ensures the accuracy of research data and animal welfare. Signup and view all the answers

What methods are utilized for health monitoring in laboratory settings?

Necropsy, serology, microbiology, and parasitology. Signup and view all the answers

Identify one viral infection that can lead to liver swelling in laboratory animals.

Murine hepatitis virus (MHV). Signup and view all the answers

What type of infection is associated with the presence of Taenia taeniaeformis in laboratory animals?

Cestode infection (tapeworm). Signup and view all the answers

What are the primary symptoms observed in Murine Respiratory Mycoplasmosis (MRM) in mice?

Primary symptoms include torticollis, chronic respiratory infection, purulent rhinitis, otitis, and bronchopneumonia. Signup and view all the answers

Explain the modes of transmission for MRM and their implications for disease spread.

MRM can be transmitted via aerosol, in utero, and sexually, allowing for both direct and indirect spread among murine populations. Signup and view all the answers

Describe the macroscopic features that characterize the lungs of a mouse affected by MRM.

Macroscopic features include purulent exudate in the trachea and bronchi, yellow foci of bronchiectasis, and areas of consolidation ranging from red to grey. Signup and view all the answers

What histological change is observed in mice with MRM, and how does it differ from normal lung tissue?

Histologically, there is peribronchiolar lymphoid hyperplasia, which differs from the normal bronchus-associated lymphoid tissue (BALT) typically found in mouse lungs. Signup and view all the answers

Identify the key diagnostic methods used for identifying infections caused by Corynebacterium kutscheri.

Diagnosis involves culture methods and Gram staining from lesions, revealing Gram-positive organisms. Signup and view all the answers

What are the primary clinical manifestations of hydropic swelling in the intestinal villi?

Hydropic swelling causes malabsorption, diarrhea, and growth disturbances. Signup and view all the answers

How is the diagnosis of Reovirus infections typically confirmed?

Diagnosis is confirmed through serology. Signup and view all the answers

What are the symptoms associated with Eimeria spp. infections in mice?

Symptoms include enteritis, typhlitis, colitis, and diarrhea that may contain blood. Signup and view all the answers

What is the role of Cysticercus fasciolaris in the life cycle of Taenia taeniaeformis?

Cysticercus fasciolaris acts as an intermediate host for the development of Taenia taeniaeformis. Signup and view all the answers

What treatment is recommended for Myocoptes musculinus infestation in laboratory mice?

Ivermectin is administered at 8 mg/L in drinking water once weekly for three weeks. Signup and view all the answers

What key factors should be considered before collecting samples from wildlife species?

Important factors include the health status of the animal, the need for personal protective equipment (PPE), and the potential for zoonotic diseases. Signup and view all the answers

List at least three zoonotic diseases mentioned that could be of concern when collecting samples from sick or dead animals.

Rabies, Mycobacterium, and West Nile virus. Signup and view all the answers

Identify the five key considerations for sample shipment outlined in the content.

Avoid cross-contamination, prevent sample decay, prevent leakage, ensure proper identification, and label each container appropriately. Signup and view all the answers

Differentiate between macroscopic and microscopic features of fatty degeneration in tissues.

Macroscopically it presents as yellow, brittle, and shiny organs, while microscopically it shows clear-bordered vacuoles with nuclei displaced to the periphery in severe cases. Signup and view all the answers

What are the distinct microscopic characteristics of hydropic degeneration?

Hydropic degeneration presents with vacuoles near the nucleus that lack clear boundaries. Signup and view all the answers

Explain the difference between degeneration and necrosis in terms of cellular reversibility.

Degeneration is reversible, while necrosis is irreversible. Signup and view all the answers

What is the physiological significance of necrobiosis/apoptosis as a form of cell death?

Necrobiosis/apoptosis represents normal, physiological cell death essential for maintaining healthy tissue turnover. Signup and view all the answers

Describe the implications of identifying clear-bordered vacuoles in tissue samples.

The presence of clear-bordered vacuoles may indicate severe fatty degeneration of tissues. Signup and view all the answers

What role do oxidizing agents such as osmium tetroxide play in the preservation of tissue structure?

Oxidizing agents react with protein side chains to form crosslinks, stabilizing tissue structure. Signup and view all the answers

Why is formaldehyde not preferred for electron microscopy preparations?

Formaldehyde is avoided because the methanol added denatures tissue components. Signup and view all the answers

Explain the primary action mechanism of precipitating fixatives like ethanol and methanol.

Precipitating fixatives reduce the solubility of proteins and disrupt hydrophobic interactions, leading to protein aggregation. Signup and view all the answers

What is the effect of combining acetic acid with alcohols during tissue fixation?

Combining acetic acid with alcohols may result in better preservation of tissue morphology by counteracting the shrinkage caused by alcohols. Signup and view all the answers

How does glutaraldehyde's effects on tissue morphology compare to those of osmium tetroxide during fixation?

Glutaraldehyde causes nuclear and cytoplasmic shrinkage, while osmium tetroxide induces swelling, balancing the overall effect. Signup and view all the answers

What labeling materials are recommended for marking vials used in sample transportation?

Color stickers, a pencil, or a histology grade permanent marker are recommended. Signup and view all the answers

How soon should a necropsy be performed after an animal's death to prevent autolysis?

A necropsy should be performed within 6-8 hours after the animal's death. Signup and view all the answers

Define a wild animal according to OIE standards.

A wild animal is defined as one that has a phenotype unaffected by human selection and lives independently of human supervision. Signup and view all the answers

What is the primary purpose of conducting a necropsy?

The primary purpose of a necropsy is to observe macroscopic changes in tissues and organs and to collect samples for further analyses. Signup and view all the answers

Why are wildlife species considered as 'savages' even if they have been tamed?

Wildlife species are considered 'savages' because the taming characteristic is not passed on to the next generation. Signup and view all the answers

Study Notes

Necropsy Procedure and Methods

Procedures for necropsy of wild animals are similar to those for domestic animals
Wild ruminants, deer, antelope, camels, and llamas follow the same procedure as domestic cattle, sheep, and goats
Wild horses, asses, zebras, elephants, hippopotamuses, and rhinoceroses are similar to domestic horses
Swine procedures are similar to domestic swine
Wild birds, wild carnivores (wolves, coyotes, bears, lions), and rodents are similar to domestic chickens, turkeys, ducklings, geese, cats, and dogs, respectively

External Examination

Skin condition is examined
Extremities are checked
Ectoparasites are noted
Muscle condition is observed
Eyes are inspected
Oral cavity is assessed
Skeletal structure is evaluated

Reptiles Dissection and Internal Examination

Lizards and snakes are placed flat on their backs for dissection
An initial incision is made along the ventral midline
On laterally compressed animals like chameleons, the necropsy is performed with the animal on its side
Limbs are dislocated to access the internal organs
An incision is made along the ventral midline from the cloaca to the forelimbs and the shoulder blade
The fat pads of P. molurus bivittatus and T. merianae are located throughout the body cavity and around the heart for one species and near the pelvis for the other
The heart of T. merianae is located under the rib cage, the heart of P. molurus bivittatus is also located under rib cage

Recommended Methods of Euthanasia

Chemical methods involve overdoses of injectable anesthetic agents (including barbiturates and potassium chloride)
Inhaled anesthetics, carbon dioxide, carbon monoxide, and other inert gases are acceptable for small avian and mammalian species when other methods are not available
Firearms are acceptable for free-ranging, captured, or confined wildlife when the bullet is placed in the head to target the brain
Exsanguination may be applied as an adjunct or first step after the animal is anesthetized
Cervical dislocation or decapitation is useful for small mammals and birds
Thoracic compression should only be applied to animals that are deeply anesthetized or unconscious as a final method to confirm death

Data Recording

Case identification data (reference code, date, time, location, client information) are recorded
Information about the person in charge, the person conducting the necropsy, and who sends the sample is included
Anamneses, clinical history of the group of animals or specimens (including previous diagnoses or mortalities) are recorded
A summary of the situation at the time of the inspection or visit is documented
Detailed records of observations and findings during the necropsy are kept
Information about the type and number of samples obtained for laboratory analysis is documented

Specimen Reception

Specimen is received and logged
Containers are typically labelled for ease of identification.

Specimen Unpacking

A technician unpacks the specimen

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Description

This quiz covers key topics related to laboratory animal health and infectious diseases. It addresses the causes and zones of infarction, the role of laboratory animals in research, and specific diseases affecting them. Participants will also review health monitoring techniques and the pathological features seen in affected animals.