Molecular diagnosis of hemoplasma infection in cats and sheep with hematological studies.

Background: Diagnosis of hemoplasma infections is currently based on microscopical examination of blood smears, together with the results of specific polymerase chain reaction (PCR) assays.

Aim: In the present study, molecular detection using 16S rRNA was used as a diagnostic approach for detection and genetic characterization of the hemoplasma in cats and sheep. However, hematological studies were applied to sheep showing emaciation.

Methods: In the present study, blood smears examination, hemogram, blood cells count, and molecular detection using 16S rRNA were used as a diagnostic approach for the detection and genetic characterization of the hemoplasma in cats and sheep.

Results: We found that hemoplasma incidence in cats in the examined samples was 8%, and Candidatus M. haemominutum was detected at 202 bp band size by 16SrRNA and Candidatus M. haemovis in sheep. The infection rate in the examined sheep was 4% (2/50) by nested PCR giving specific bands at 1,060 and 506 bp. Giemsa-stained blood smear from an affected sheep with hemoplasma showed a small oval to ring-shaped organism noticed on the surface of erythrocytes. The organisms have other variable shape (cocci, small rods are arranged in short chains) with the presence of free organisms in the background of blood smear. Haemovis are epicellular parasites which attached in the indentation and invagination of the erythrocyte surface causing the direct injury of red blood cells. Poikilocytosis was very obvious. Abnormal features of red corpuscles were noticed as pointy or thorn-like projections. Destruction of erythrocytes causes anemia; these features led to a significant decrease in total erythrocyte count, and polychromasia was noticed. Moreover; neutrophils with foamy and opaque cytoplasm were observed. The leucogram showed leucopenia due to lymphocytopenia while, neutrophils rose, monocytes, and eosinophils showed an elevation level.

Conclusion: This is the first microscopical and molecular identification of haemovis in sheep in Giza, Egypt. Further investigation is recommended for epidemiology and control measures of haemotropic mycoplasma.