Detection of Leishmania in samples from dogs as a preventive measure

Canine Leishmaniasis is a zoonotic disease caused by Leishmania infantum, whose most frequent signs in dogs are weight loss, skin lesions, lymphadenomegaly, muscle atrophy, vomiting and diarrhea. In addition to dogs, around 70 species of mammals, including humans, are optimal hosts for Leishmania.

How is the disease transmitted from dogs to humans?

Transmission of Leishmaniasis between dogs and humans occurs when a mosquito that has fed on the blood of an infected dog bites a human. When this happens, the blood of the mosquito that contains the Leishmania mixes with ours, and the Leishmania invades the phagocytic cells of different tissues of our body, which it uses to replicate. 

As a result of this replication, many Leishmania “offspring” are formed, eventually breaking through the cell membrane and re-entering the bloodstream. Thus, when a new mosquito feeds on our blood, it will be transmitted again, perpetuating its life cycle.

In humans, the usual clinical manifestations of Leishmania infection are fever, anemia, fatigue, hepatosplenomegaly, and suppression of immunity, leading to death in the most extreme cases. 

Due to the severity of symptoms in humans, as well as the high level of exposure to infection around the world (around 350 million people exposed), it is advisable to go to the veterinarian when any of the signs described above are noticed, and thus prevent the spread of the disease, both to other animals and humans.

Protocol for the detection of Leishmania

There are different tests for the diagnosis of Leishmaniasis in dogs, the most common, due to its convenience, being the rapid test in serum, which detects seroconversion. To perform this test, a sample of approximately 1-1.5 ml of blood from the dog must be taken in a 5 ml tube with heparin. The sample is then centrifuged at 2,500-3,000 rpm for 5-10 minutes. 

After centrifugation, the sample is divided into two fractions. The upper fraction, with a clear and transparent appearance, corresponds to blood plasma, which is transferred to another tube. Finally, a drop of the plasma is taken and placed on a strip provided by the test. The reagent, also provided by the test, is added and the result is revealed.

Leishmaniasis is a zoonotic disease, easily transmitted from dogs to humans. One of the preventive measures is analysing seroconversion for Leishmania in plasma samples originated from dogs suspected of infection, for which it is necessary to extract the plasma from whole blood through a simple centrifugation step, which will be done with an equipment like the Microcen 24 centrifuge.

This equipment has a rotor to run up to 8 blood tubes, easily programmable in speed and time. Its small size makes it the right choice for clinics and small veterinary laboratories.