Veterinary Medicine Notes

Physical Exams and Weight Importance

Weight is a critical indicator of an animal's health, especially in chronic conditions, often noticeable before other symptoms.
Temperature can be affected by stress, particularly in cats. Allow the animal to relax before taking their temperature to get an accurate reading.
Consider the animal's hair coat and general appearance for signs of underlying issues like hair loss (alopecia).
Note the animal's behavior, as changes can indicate illness or discomfort. Veterinarians need to understand normal animal behaviors to recognize deviations.

The body has nonspecific defenses (urine, tears, skin) and internal responses to combat infectious agents.
A specific immune response involves antibodies reacting to antigens (bacteria, viruses). Vaccines introduce a weakened form of the antigen to stimulate antibody production.
Vaccines do not contain the actual disease but prime the body to respond quickly upon exposure to the real pathogen, reducing or eliminating lag time.
Not all vaccines prevent the disease entirely; some mitigate clinical signs and reduce shedding of the pathogen.

Killed Vaccines:
- Contain a killed form of the bacteria or virus.
- Do not replicate in the body, leading to a potentially weaker immune response.
- Adjuvants are added to stimulate a stronger immune response by attracting immune cells to the injection site.
- Adjuvants can cause fibrosarcomas (vaccine-induced sarcomas) in genetically predisposed cats, particularly with rabies and feline leukemia vaccines. Non-adjuvant rabies vaccines exist.
Modified Live Vaccines:
- The agent is passed through cell lines to reduce its ability to cause disease.
- Offer a stronger immune response due to replication within the body.
- Rabies vaccines are never modified live due to the high risk of reversion to an infectious state.
mRNA Vaccines:
- Rarely used in animals.
Subunit Vaccines:
- Use a subunit of the antigen to stimulate an immune response.
Recombinant Vaccines:
- Replicate in another organism and are administered via injection or nasal drops.
Oral Vaccines:

Maternal Antibody Interference:
- Puppies and kittens receive maternal antibodies via the placenta, providing initial protection.
- Maternal antibodies wane over time (typically by 16 weeks).
- The offspring's immune system matures over time, becoming fully competent around 16 weeks.
- Maternal antibodies can neutralize vaccine antigens, reducing the vaccine's effectiveness (maternal interference).
- Vaccination protocols involve multiple vaccinations to overcome maternal interference, but protection levels remain uncertain.
- Even with vaccinated mothers and multiple vaccinations, susceptibility to diseases like parvo remains a concern.
Improper Handling and Storage:
- Vaccines must be refrigerated and protected from heat exposure, which can compromise their efficacy.
Individual Animal Factors:
- Some animals (e.g., Dobermans, Pitties, German Shepherds, Rottweilers) have a genetically reduced ability to mount an adequate vaccine response, especially to parvo.
- Severely debilitated animals may also have a reduced response.

Every puppy and kitten is presumed to have roundworms due to their effective biological cycle.
Roundworms have a complex life cycle:
- Adult roundworms in the GI tract reproduce sexually and release eggs into the feces.
- Eggs are ingested and hatch, with larvae migrating through the intestinal mucosa to various body parts (liver, muscle), forming cysts.
- In pregnant queens, hormonal changes activate these cysts, releasing larvae.
- Larvae travel to the lungs, are coughed up, swallowed, and mature in the intestine to restart the cycle.
Fecal-oral transmission is not direct; eggs require 24-48 hours to become infectious in the environment.
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