Specific-pathogen-free (SPF) is a term used for
laboratory animals that are guaranteed free of particular
pathogens. Use of SPF animals ensures that specified diseases do not interfere with an experiment. For example, absence of respiratory pathogens such as
influenza
Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms ...
is desirable when investigating a drug's effect on
lung
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
function.
Practical
Completely germ-free
The animals can be born through a
caesarian section then special care taken so the newborn does not acquire infections, such as use of sterile isolation units with a
positive pressure differential to keep all outside air and pathogens from entering. Everything that needs to be inserted into the isolator, such as food, water and equipment needs to be completely sterilized and disinfected, and inserted through an airlock that can be disinfected before opening from the inside.
A disadvantage is that any contact with
pathogens may be fatal. This is because the animals have no protective
bacterial microbiota on the
skin or in the
intestine
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...
or
respiratory tract
The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa.
Air is breathed in through the nose to th ...
, and because they have no natural
immunity to common infections as they have never been exposed to them.
Specific-pathogen-free
To certify SPF, the population is checked for presence of (
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
against) the specified pathogens.
For SPF eggs the specific pathogens are:
Avian Adenovirus Group I,
Avian Adenovirus Group II (HEV),
Avian Adenovirus Group III (EDS),
Avian Encephalomyelitis,
Avian Influenza (Type A),
Avian Nephritis Virus,
Avian Paramyxovirus Type 2,
Avian Reovirus S 1133,
Avian Rhinotracheitis Virus;
Avian Rotavirus;
Avian Tuberculosis M. avium;
Chicken Anemia Virus;
Endogenous GS Antigen;
Fowl Pox;
Hemophilus paragallinarum Serovars A,B,C;
Infectious Bronchitis - Ark;
Infectious Bronchitis - Conn;
Infectious Bronchitis - JMK;
Infectious Bronchitis - Mass;
Infectious Bursal Disease Type 1;
Infectious Bursal Disease Type 2;
Infectious Laryngotracheitis;
Lymphoid Leukosis A, B;
Avian Lymphoid Leukosis Virus;
Lymphoid Leukosis Viruses A,B,C,D,E,J;
Marek's Disease (Serotypes 1,2, 3);
Mycoplasma gallisepticum;
Mycoplasma synoviae;
Newcastle Disease LaSota;
Reticuloendotheliosis Virus;
Salmonella pullorum-gallinarum ;
Salmonella species;
Minimal disease status
When by accident some infection does occur, the population is said to have minimal disease status.
Monitoring
The population is regularly checked to ensure the status still holds.
Applications
SPF eggs can be used to make
vaccines.
Mice raised under SPF conditions (no ''Helicobacter pylori'') were shown to develop
colitis rather than
enterocolitis.
See also
*
Filtered Air Positive Pressure
*
Gnotobiotic animal
References
{{Reflist
Animal testing
Animal models