Secretions, Excretions and Other Specimens

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Secretions, Excretions and Other Specimens

Part from tissue and blood which are the most commonly used samples, a number of other specimens can be submitted for laboratory diagnosis.

Faeces

Faeces can be sent for parasitology exmination, bacteriology or virology.

5 to 10g of faeces should be collected from the rectum (or cloaca) or collected as voided. Faeces are placed in labeled a sterile container, and submission form is filled. Transport medium may be required for some examination and the laboratory should be contacted first. For parasitology, fecal material should fill the recipient or be completed with sterile water as air accelerates hatching of the eggs. 

Faeces are best stored and transported at 4°C.

Urine

Although there are not widely used, urine samples can be used for the identification of pathogen, specially using PCR techniques. Urine samples should be collected in screw cap tubes, in amounts of 5-10 ml and kept refrigerated.

Skin

Skin specimen can be sent for bacteriology and virology. In diseases producing vesicular rashes or where lesions are exclusively in the skin, samples are taken from the lesions themselves.  

Scrapings of the lesion may be taken; 2 g of affected epithelial tissue is taken as aseptically as possible and placed in 5 ml phosphate buffered glycerin virus transport medium at pH 7.6. Additionally, the vesicular fluid should be sampled where unruptured vesicles are present; if possible, vesicular fluid should be aspirated with a syringe and placed in a separate sterile tube. 

Pus from abscess can be collected with a sterile swab and kept in a sterile universal. Material is preferably not colected from the center of the lesion. Approximately 3ml is required for bacteriology Material from recently formed abscesses is preferred.

Plucked hair or wool samples may be useful and, in birds, feather follicle skin can be taken for culture for Marek’s disease.

Eye

Eyes swabs can be submitted for bacteriology and virology. A swab of the surface of the conjunctiva may be taken gently, holding the palpebra apart. The swab is then broken off into transport medium. Scrapings may also be taken on to a microscope slide. The handles of metal-handled swabs are useful for this, to ensure that sufficient cells are removed for microscopic examination.

Nasal discharge (saliva, tears)

Samples may be taken with dacron, cotton or gauze swabs, preferably on wire handles as wood is inflexible and may snap. It may be helpful if they are first wetted with transport medium. They should be allowed to remain in contact with the secretions for up to 1 minute, then placed in transport medium and sent to the laboratory without delay at 4°C.

Genital tract and semen

Genital tract and semen can be submitted for bacteriology and virology. 

Samples may be taken by vaginal or preputial washing, or by the use of suitable swabs. To minimise contamination from the perineal/vulval area, insert the swab through a vaginal speculum. The outer plastic case of a disposable syringe may be adapted for this purpose. Alternatively a guarded swab may be used. Sometimes the cervix or urethra are also sampled by swabbing. 

Samples of semen are best obtained using an artificial vagina or by artificial stimulation. The sperm-rich fraction should be present in the sample and contamination by antiseptic washing solutions must be avoided.

Samples should be sent at 4°C

Milk

Samples of milk can be used for serological tests, bacteriology and virology. They should be collected after cleansing and drying the tip of the teat. The initial stream of milk should be discarded. Milk samples should be submitted in screw top tubes frozen or placed on ice packs. Less than 1 ml is required, and larger volumes are undesirable, especially if the samples are frozen. When serology is planed, samples should not be frozen. 

If there is not enough milk, samples can be taken alternatively from the tank.

Honey bees

Adult bees, either dead or moribund, may be collected in the vicinity of the colonies. Live bees should be killed by freezing. Brood samples are taken by removing a piece of brood comb that shows abnormalities. This should be wrapped in paper and placed in a box for transport to the laboratory.

Other arthropods

Parasitic arthropods can be sent for identification, they should be collected in sampling boxes with minimal damage to the body and conserved either by freezing or in 10% formalin.

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