Hematologic values in domestic pigeons naturally infected with Mycobacterium avium subsp. avium

Avian mycobacteriosis is an important disease of birds and is most often caused by Mycobacterium avium or Mycobacterium genavense. However, little information on the hematologic changes associated with this infectious disease in pigeons has been published. The aim of this investigation was to compare the hematologic parameters of domestic pigeons (Columba livia var. domestica) naturally infected with M avium subsp. avium (MAA) with clinically healthy pigeons. Blood samples were collected from 12 pigeons with suspected mycobacteriosis and 12 clinically healthy pigeons. All the birds with suspect infections were necropsied, and affected organs were cultured and examined on histopathology for mycobacteriosis. Total leukocyte and erythrocyte counts were performed on each blood sample with the Natt and Herrick method using a Neubauer hemocytometer. White blood cell (WBC) differential counts were performed on Giemsa-stained blood smears. Packed cell volumes (PCVs) were measured using the microhematocrit technique. Hemoglobin concentrations were measured with a spectrophotometer using the cyanomethemoglubin method. Mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentrations (MCHCs), and mean cell volumes (MCVs) were calculated manually. All of the infected birds had typical histopathologic findings of avian mycobacteriosis, which were confirmed using microbiologic and molecular methods to detect MAA. The hematologic data from the two groups were compared. The total WBC, heterophil, lymphocyte, and monocyte counts were significantly higher, and the PCV, HGB, MCH, and MCHC values were significantly lower in the infected birds compared with the clinically healthy pigeons.