Specific-pathogen-free (SPF) is a term used for

laboratory animal Animal testing, also known as animal experimentation, animal research, and ''in vivo'' testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study. This ...

s that are guaranteed free of particular

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s. 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 Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or mo ...

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 Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

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 ...

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 Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity desc ...

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 A vaccine is a biological preparation that provides active acquired immunity The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and pro ...

. Mice raised under SPF conditions (no ''Helicobacter pylori'') were shown to develop colitis rather than

enterocolitis Enterocolitis is an inflammation of the digestive tract, involving enteritis of the small intestine and colitis of the colon. It may be caused by various infections, with bacteria, viruses, fungi, parasites, or other causes. Common clinical manif ...

References

{{Reflist Animal testing Animal models