VPA 221: Veterinary Entomology and Acarology (1+1)

Identification

IDENTIFICATION OF ECTOPARASITES

• Mouth parts of flies, lice, bugs, fleas and ticks be subjected to boiling with 10% NaOH or KOH solution to render the non-chitinous portions transparent
• Such alkali treated materials should be thoroughly washed in water, dehydrated in ascending grades of alcohol and cleared in phenol, when the chitinous structures which help in specific identification are brought into relief
• Permanent slides are made by mounting these cleared specimens in Canada balsam
• For quick and easy identification, treatment with a drop or two of Berlese fluid, is followed.  This is mostly used in identification of members of the class Insecta and especially order Diptera
• Berlese Fluid
              Chloral hydras  - 160 gms
              Gum Arabic   - 15 gms
              Glucose   - 10 gms
              Glacial acetic acid  - 5 c.c  
              Water    - 20 c.c
• Mites can be identified by examination of the skin scraping
  • Take the sample of skin scrapings in a test tube, Add 5 c.c of 10% NaOH or KOH solution and boil till a homogeneous suspension is got
  • Pour this into a test tube and centrifuge the fluid for two minutes at 1000 RPM.  Examine a drop of the sediment under a microscope for the presence of mites.
• Most of the dipterous larvae have characteristic behaviour and microscope structures while a few like the muscids can be identified by examining the posterior spiracles under a microscope.  This is done by snipping off the posterior end of the larvae and boiling them in 10% NaOH or KOH solution
• While forwarding insects for identification they should be killed and properly pinned or preserved 
• Ticks need not be killed, but sent alive in a tube along with a small quantity of moist sand or paper