A study on immunological response of leukocytes to ticks in cattle reared in sub-tropical region of Khyber Pakhtunkhwa Pakistan

Parasitic infestation in cattle is a common phenomenon in sub tropical conditions of Khyber Pakhtoonkhwa. The present study was designed to investigate the immune response of differential leukocytes count (lymphocytes, monocytes, eosinophils, basophils and neutrophils) against ticks in cattle under sub tropical conditions in the hilly areas of northern Khyber Pakhtunkhwa, Pakistan. A total of 40 tick infested cattle were divided into four age groups having 10 animals in each group i.e. G1 (3 years), G2 (4 years), G3 (5years) and G4 (6 years) were evaluated on the basis of different leukocyte count. The overall means counted in the present study were 3144.97±736.62 mm, 543.03±93.28/mm, 610.37±154.60/mm, 51.4±7.38mm and 32069.175±273.18/mm for total lymphocytes, monocytes, eosinophils, basophils and neutrophils respectively. There was non-significant association was recorded among different age groups on differential leukocytes count in tick infested cattle except on eosinophils count. As a result it was concluded that there is poor immune response of leukocytes to ticks except eosinophils in cattle.


Introduction
Ticks are the blood feeding ecto-parasites having immense importance in animal health. They are different types of ticks i.e. hard and soft ticks. Both are acting a great threat to farmer community, particularly to cattle owner by transmitting different types of tick borne diseases such as babesioses, theileriosis etc. The neutrophils ratio is mostly lower than the lymphocytes ratio (N:L) in case of cattle and sheep as compare to the other domestic species of the animals [1]. Goats older than three year of age have higher ratio of neutrophils & lymphocytes ratio than cattle and sheep but the goats having age less than three years have the same neutrophils and lymphocytes ratio as cattle and sheep [2]. In case of mild moderate inflammation in ruminants, there is frequent neutrophilia while normal neutrophils are seen in chronic stage of inflammation [3]. Neutrophilia associated with inflammation may or may not include a left shift, toxic changes, and hyperfibrinogenemia. In most of the cases the inflammatory neutrophilia has been observed in bacterial, viral, fungal, protozoal and parasitic infections affecting mammary gland, respiratory tract, gastrointestinal tract, liver, heart, urinary tract and central nervous system in goats, sheep and cattle [4]. Eosinophils are the most important leukocyte cells playing an important role in allergic reactions and parasitic infections. The eosinophilia has been recorded in different endoparasitic infections in goats [5], cattle and sheep [6]. However, it is not important that every parasitic infection must have the eosinophilia [7] although it showed that there was no increase in the peripheral eosinophils numbers when compared with controls to tick infested cattle. Different studies showed that basophils also react like eosinophils (increase in number) with response to any allergic reactions and parasitic infestation i.e. cattle infested with ticks as reported by [7] and in goats experimentally infected with nematodes [8]. Cattle infected with flukes showed no increase in basophil numbers and sheep appear to be less likely to display basophilia than some other species [9]. Lymphocytes are also not common in case of large and small ruminants but some time it occurs in viral infection and in chronic inflammatory conditions. The most frequent cause of lymphopenia in ruminants is the corticosteroid induced stress response. Infection with bacteria, septicemia and other acute viral infection is also responsible for lymphopenia [10] Stress, endotoxemia, acute and per acute inflammatory conditions due to any reasons are responsible for monocytosis [11]. Therefore the present study was conducted to determine the the immune response of different differential leukocytes count to ticks in cattle.

Materials and methods Study location
A total of 40 tick infested cattle having age of three to six years were selected randomly for this study. These animals were than divided into four groups on the basis of their age i.e. G1 (3 years), G2 (4 years), G3 (5 years) and G4 (6 years) such as each group containing10 animals.

Sample collection
The blood samples were collected from 40 animals and further experiments were carried out in Veterinary Research and Diagnostic Laboratory Balogram Swat. The tests for differential leukocytes (DLC) were carried out through slide method. Statistical Analysis: After collection of data, it was subjected to statistical method of analysis of variance as suggested by [12].

Lymphocytic count
The overall lymphocyte count in tick infested cattle has been presented in (Table  1) where the overall means of lymphocytes were 3144.97±736.62/mm 3

Monocytes count
In the present study the overall mean of monocytes were also recorded (492.025±93.39/mm 3 ) as presented by ( Table 2). The current Study on monocytes indicates that the animals in Group 1 have been higher monocytes counts (559.50±178.0 mm 3 ) while cattle in Group 3 have been lower monocytes counts (425.00±50.0 mm 3 ). However, the mean monocytes count in G2 and G4 were 439.00±35.17 and 544.60±109.50/mm 3 , respectively. Analysis of variance showed that there was non-significant difference in monocytes count among different animal groups.

Eosinophils count
The overall eosinophils counts of tick infested cattle under experiment are shown in (Table 3). The overall mean of eosinophils count was 623.20.±154.46/mm s recorded. The animals in Group 4 had been higher eosinophils count 678.00±144.35/mm 3 than cattle in Group 2 where it was 564.00±109.64/mm 3 whereas, the mean eosinophils count of G1 and G3 were 646.80±224.38 and 604.00±139.48mm 3 , respectively. Analysis of variance showed that there was highly significant difference in eosinophils count among different groups.

Neutrophils count
The overall mean of neutrophils count was 2069.18±273.18/mm 3 ( Table 5). The animals in Group1 had been higher neutrophils count 2110.20±652.2/mm 3 than cattle in Group 2 where it was 2010.00±39.01/mm 3 . The mean neutrophil count of G3 and G4 were 2050.00±32.04 and 2106.50±369.50/mm 3 respectively. Analysis of variance showed that there was no significant difference in neutrophils count among different age groups.