Haemato-biochemical and oxidative status of buffaloes naturally infected with Trypanosoma evansi

Highlights

• Trypanosoma affected animals revealed significant reduction in haemoglobin and PCV.

• Infected animals showed rise in lipid peroxidation, super oxide dismutase catalase.

• Rise in aspartate transaminase was observed in infected animals.

• Other haemato-biochemical indices did not show variations in experimental animals.

Abstract

Blood samples were collected from 05 clinically healthy and 10 adult female water buffaloes naturally infected with Trypanosoma evansi. Confirmation of disease free and infected status of buffaloes was made on clinical signs, observation of T. evansi parasites in the blood smear and duplex PCR based assay. Blood samples were evaluated for levels of haemoglobin (Hb), packed cell volume (PCV), differential leucocytes count (DLC), lipid peroxidation (LPO), calcium, phosphorous, magnesium sodium and potassium and activities of superoxide dismutase (SOD), catalase (CAT), aspartate transaminase (AST), lactate dehydogenase (LDH) and alkaline phosphatase (ALP). The results of the study revealed substantial decrease in levels of Hb, PCV and increase in LPO, SOD, CAT and AST in infected animals compared to healthy animals. However other haematological and biochemical indices did not show significant variations in infected and healthy buffaloes. The enhanced erythrocytic oxidation and reduction of hematological indices, suggests that the enhanced oxidation of the erythrocytes may be a contributory factor in erythrocytic destruction and progression of the anaemia in T. evansi infection in water buffaloes.

Introduction

Trypanosomiosis, popularly known as ‘surra’ is widely prevalent in domestic animals throughout India with Trypanosoma evansi being the causative agent in most of the clinical cases (Pathak and Chhabra 2011). This parasite is mechanically transmitted by biting flies of the genus: Tabanus (Singh and Tewari, 2012). The disease can be acute in young animals and pregnant females, which die within a few weeks, but the usual form in endemic areas is a chronic one that lasts for years and ultimately leads to cachexia and death (Maudlin et al., 2004). In buffaloes, it is an asymptomatic carrier state with occasional acute or peracute infection that may lead to death within a few weeks. The acute form of disease is noticed with intermittent fever, anemia, emaciation and production losses and a slower course of disease shows, dullness with recumbency or staggering gait, labored breathing, lacrymation, bellowing, profuse salivation, twitching of muscles often terminating in convulsions and death (Pathak and Chhabra 2011). The chronic form lasts for years and is characterized by dullness, anemia, emaciation, recurrent fever, edema in dependent part of body, conjunctivitis, lacrymation, enlargement of the superficial lymph nodes, abortions, infertility, reduced milk yield, progressive emaciation and lowered work output (Gutierrez et al., 2005, Jaiswal et al., 2015). Many investigators revealed alterations in blood constituents and tissue lesions in trypanosomiosis affected animals of different species (Hilali et al., 2006, Saleh et al., 2009, Ohaeri and Eluwa, 2011, Singh et al., 2012). Furthermore some reports have shown important role of free radical induced oxidative stress in pathogenesis of trypanosomiosis (Ogunsanmi and Taiwo, 2007, Umar et al., 2007, Akanji et al., 2009). The infection of trypanosomes results in production of large amounts of reactive oxygen species (ROS) and free radicals (FR) which act as cytotoxic agents (Gutteridge, 1995) damaging vital components of the cell, including proteins and lipids (Murray et al., 2003). The erythrocyte, due its role as O₂ and CO₂ transporter, is under constant exposure of free radicals (Harvey, 1997). Thus, the evaluation of oxidative and haemato-biochemical indices helps to determine degree of damage to hosts tissues caused by the infection (Otesile et al., 1991) and the health status of the infected animals (Coles, 1986).

Keeping these in mind the present study was designed to assess the haemato-biochemical and oxidative status as indicators of oxidative damage of the erythrocytes and their contributory role as factors causing cell lyses and anaemia in buffaloes naturally infected with trypanosomiosis.