Morphology protozoa in thick drop
The study should take into account, that in the middle, thicker part droplet detection probability parasites large, however, they are less colored, than the edge. The thinner part droplets form better preserved parasites.
In the large drop P. vivax It differs from other agents of significant size and polymorphism. Annular trophozoites rarely retain their shape, more often they are broken, while a small piece of the core adjacent cytoplasm round, an elongated triangular shape or (when the elongated shape of the cytoplasm to the nucleus resembles an exclamation mark). If the break occurred against the cytoplasm of the nucleus, then its two halves are arranged on both sides of the core, whereby a figure, reminiscent of the swallow.
Usually found and mature schizonts, cytoplasm are often broken, and near the nucleus are several different sized lumps of cytoplasm. Some schizonts indistinguishable from gametocytes, as the distinctive features in the large drop erased. Morula in a thick drop easily recognized, as the merozoites they gathered around a handful of dark brown pigment.
In a well-painted thick drop of the red blood cells is stored in the form of delicate pinkish discs with grit Schuffner's, lie in the background of their parasites. This feature is very important, because there is no other species of Plasmodium (it should be understood, that in some cases the affected red blood cells completely leached). Remains of parasitized erythrocytes in the large drop and saved P. oval.
Annular trophozoites P. malariae a thick drop do not differ from the rings P. vivax. Schizonts look like a well-defined, round or oval lumps, without vacuoles. Immature schizonts less mature. Morula well preserved, 6-12 Merozoites arranged around a handful of pigment. Parasites are available outside the cells, parasitized erythrocytes completely leached.
Small ring P. sickles often retain their shape, and large deformed. Gametocytes easily identified by their characteristic shape. Infected erythrocytes are completely leached.
When difficulties in diagnosis should be a re-examination of blood. In the case of a three-day (a day) and a four- (two days) malaria during the second study, the patient's blood found amoeboid trophozoites, and in the tropical - only annular.
Well distinguishable morula: nondecomposed sea P. vivax It consists of 12-18 merozoites, a cluster of dark- brown pigment is nearer its periphery; morula P. malariae It includes 8-12 merozoites, collected in a rosette around golden yellow pigment; morula P. sickles It consists of 12-24 merozoites, closer to the periphery of a handful of black pigment is almost.
In the study of thick film should pay attention to polihromaziyu, because, more parasites patient, the greater the number of red blood cells are destroyed, especially pronounced in the large drop polihromaziya (a result of increased revenues in the blood of young, immature erythrocytes).
It is necessary to take into account the, what under the influence of chemotherapy drugs malaria parasites change: their nuclei can become leaner, intensely colored or have looser, hypochromic. The cytoplasm may acquire a glassy tone, vacuolated and decay. Under the action of quinacrine pigment is pushed out of the parasite, making it difficult to, and sometimes it makes it impossible to recognize the malaria parasite in a thick drop.
