Babesia gibsoni - Microscopic exam; Molecular diagnosis (PCR)

Babesia gibsoni is a protozoan parasite of dogs, genus Babesia, family Babesiidae, causing canine babesiosis, although they have also recorded isolated cases in humans. The disease is considered endemic in Europe, South Africa, Asia and America.

The life cycle of this organism involves an intermediate host where mature, usually infected ticks, which transmit the infection during feeding releasing sporozoites into the bloodstream of the dog. This transmission requires two to three days. Known vectors include Rhipicephalus sanguineus, Haemaphysalis bispinosa and H. longicornis. However, the disease can be transmitted through the use of vaccination needles, surgical equipment, blood direct contamination or through injuries in dog fighting. In some instances, Babesia gibsoni has been detected in newborn puppies, so it is also considered as transplacental transmission route of infection.

Babesia gibsoni develops in erythrocytes of the host, which can be visualized as round or oval shaped bodies or ring with a length of 1 to 2.5 microns. Inside red blood cells, Babesia gibsoni begins to divide, becoming a new form called merozoite that could be taken with erythrocytes by a new tick for food. After ingestion by ticks, Babesia gibsoni sexual reproduction begins (gamogony), which after the formation of the zygote and the oocyst, resulting in numerous sporozoites that accumulate in the salivary glands of ticks.

Clinical signs include lethargy, weakness, vomiting, fever, pale mucous membranes and dark colored urine. In addition, the disease can cause severe hemolytic anemia and thrombocytopenia between 1 and 3 weeks of infection that can compromise the lives of young dogs occur. Also, other symptoms including neurological and respiratory signs may occur. In some dogs, the parasitemia persists for 3 or 4 weeks thereafter becoming chronic carriers of the infection. Although acute infection is associated with severe anemia and thrombocytopenia, many dogs survive the acute phase and become chronic carriers.