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Hematological methods in Parasitology. Virtual Lab

Trypanosoma in blood

The detection and identification of parasites is the ultimate test of a parasitic disease. A microscopic analysis of blood is essential to identify the parasites that may exist in it. When these are in the blood or other body fluids, they must be analyzed for their presence or not. There are also concentration techniques, such as in coprological analysis.

Many of the techniques used are the usual ones for the microscopic analysis of fluids, others are more specific and require microscopic techniques of fixing and staining. The very specific techniques are performed according to the symptoms of illness that the person or the animal has, at the request of the medical or veterinary doctor.

There are two common techniques in examining blood samples for detection of parasites, smears and concentration. Giemsa staining is widely used for parasitic protozoans, using acid (eosin) and basic (methylene blue) dyes, Wright's differs from the former by the use of methanol in its composition, thus saving the previous step before staining the sample.

In addition to direct techniques, there are other indirect techniques, such as immunodiagnosis. The use of laboratory animals is another technique used through inoculation, usually in rats, mice or hamsters.


- Reading: Veterinary Parasitology. Blood Parasite Examination
- Reading: Wikipedia. Giemsa stain
- Reading: Wikipedia. Wright' stain


The lab experiment consists of an introduction to the techniques used for the detection of parasites in blood samples.

Preparing and staining blood film

- Reading: DPDX. Preparation of blood smears 

Examination the blood film of parasites

- Reading. WHO. Microscopic examination of thick and thin blood films for identification of malaria parasites

Wright and Giemsa stain

- Reading: Wikipedia. Wright's stain
- Reading: Wikipedia. Giemsa stain

Ways to perform the experiment

1. In Laboratory

The laboratory that performs experiments of parasitic hematology, must have a supply of samples, adequate instruments and staff training. Although the cost of the instruments is not very high, the problem is the supply of samples, although the practice can be performed  with clean blood of parasites.

2. In Home Lab

There are possibilities for setting up a low cost home microscopy lab (in spanish). You should do the practice with blood that are known to safely not have parasites, in order to practice the techniques.

Organizations that can provide samples for teaching, with adequate safety and hygiene measures are hospitals, university teaching centers (usually those that teach Medicine, Veterinary or Pharmacy), animal health centers, qualified herds, centers of analysis and research in human or animal health, veterinary clinics, etc.

In case there is a possibility, even remote, that the samples of blood are suspected of propagating bacteriological or other diseases (such as livestock or sick pets), and they want to learn the techniques exclusively for livestock or zootechnical interest, should not be practiced in a home and should be extended hygiene and safety measures. They should not be manipulated in any way, as this must be done by the health professionals.

In short, this practice should only be done in a home laboratory with clean blood of parasites and diseases. Blood sampling will be done under safety and asepsis conditions.

3. Virtually

For this purpose, can be done in this same post, watching carefully the videos of the procedure of the experiment.

Questions and activities

1.- Establish in a diagram the phases of a blood parasite analysis.

2.- What parasites and parasitic forms could we observe in a blood analysis?

3.- Going to the virtual lab Identification of protozoan parasites, of the protozoa that appear, What could we observe in the blood?

4.- What are the advantages of Giemsa and Wright's stains on non-staining observations?

5.- Search the Internet and bibliography techniques and recommendations in parasitic hematology.

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