Visceral leishmaniasis is a potentially deadly human disease with an estimated occurrence of 0.2 to 0.4 million cases worldwide, causing 20,000-40,000 deaths annually [2]. In the current study, the main clinical symptoms and signs of VL patients were splenomegaly ,hepatomegaly ,fever ,weight loss ,jaundice ,skin mucosal pallor ,diarrhea ,anorexia ,abdominal pain ,general weakness and bleeding , similar to studies conducted Nepal [9] ,India [10],Yemen [7],Pakistan [11],Kuman [8],Iran [12, 13].
The present study showed that anemia, leucopenia, neutropenia, lymphopenia, thrombocytopenia, and pancytopenia were the most common hematological problem present in VL patients. These findings are in line with studies reported from Yemen [14], Nepal [9], India [15], Iran [12, 13], Sudan [16, 17], Gonder, Ethiopia [18].
In present study significantly decreased mean Hgb, RBC, HCT and RBC indices values was reported in VL patients compared to control groups, similar to report in Sudan [17]. The 96% anemia observed in VL patients in this study, is consistent with studies done in Iran (97.1%) [12] ,Yemen (100%) [14] India (100%) [7], Sudan (100%) [16],and Gondar, Ethiopia (94.4%) [18]. However, the prevalence of anemia in this study was higher than other studies done in Nepal (90%) [9] and Iran (87.3%) [13]. The cause of anemia in these VL patients may be multifactorial: sequestration and destruction of red blood cells (RBC) in enlarged spleen, immune mechanism and alterations in RBC membrane permeability, plasma volume expansion. Moreover, hypersplenism, nutritional deficiencies of iron, folate and vitamin B12 may also have some additional role. Other suggested causes include increased sensitivity to complement, inhibition of erythrocyte enzymes, production of hemolysin by the parasites and presence of cold agglutinins [1, 4].
Most of the RBC morphology of VL in this study showed that normocytic normochromic cells followed by microcytic hypochromic cells similar to studies conducted in Nepal [9],India [1, 4].The finding of this study is in contrast with previous studies conducted in India [10], Yemen [19] and Kumaon [8] , which showed that microcytic hypochromic cells was the predominant blood cell morphology followed by normocytic normochromic cells.
Total white blood cell count and neutrophil count of VL patients significantly decreased compared to controls , similar with the study conducted in Sudan [17].The prevalence of leucopenia in this study was 95% which is similar with a study done in Gonder, Ethiopia (95.4%) [18]. The prevalence of leucopenia in this study was higher than studies done in Yemen (87%) [14], Nepal (67.5%) [9], India (83.3%) [7], Iran (67.6%) [13].The cause of leucopenia is may be due to delayed presentation to hospital which was attributing to hypersplenism causing leucopenia. Neutropenia was the most common abnormality seen in 92% in this study, which was similar with a study done in Gonder (90.1%) [18], but which was higher than studies in Yemen (73.5%) [20] and Sudan (88%) [16].This increases of neutropenia may be due to destroyed premature white blood cell (especially Neutrophils) by the parasite [4].
Similarly the prevalence of Lymphopenia in this study was 73%, which was higher than in studies done in Yemen (53.2%) [14] and Gonder ,Ethiopia (37.9%) [18].The prevalence of Lymphopenia in this study was lower than study done in Sudan (94%) [16]. Also eosinopenia was observed in VL patients in this study. The result of this study is in line with pervious study conducted in India [4, 10], Yemen [14], and Sudan [16].The suggested mechanism for development of this leucopenia is due to hypersplenism [1].
Platlate count of VL patients in this study is significantly decreased compared to control groups. The result of this study is consistent with a study conducted in Sudan [17]. The prevalence of thrombocytopenia in this study was 97%, which is consistent with studies done in Yemen (94%) [14], Sudan (100%) [16] and Gonder ,Ethiopia (90.1%) [18]. However this study showed slightly higher prevalence than studies done Nepal (72.5%) [9], India (83.3%) [15], Kumaon (85%) [8], Iran (91.2 %) [12]. Splenic sequestration and immune mediated mechanisms are mainly thought to be responsible for development of thrombocytopenia [4]. Pancytopenia is the most common hematological abnormality seen in 89% VL patients in this study, similar to a studies conducted in India [7, 15], Pakistan [21], Yemen [19], Iran [13]. The reason for pancytopenia could be due to long duration of symptoms and splenomegaly before presentation leading to increased peripheral destruction of blood cells [1].