Status of oxidative stress, trace elements, sialic acid and cholinesterase activity in cattle naturally infected with Babesia bigemina

Host oxidative stress in piroplasmosis: A review in domestic animals

Piroplasmida is an order of economically important blood parasites, including Babesia, Theileria, and Cytauxzoon, transmitted to mammals by ticks. Oxidative stress is a state in which the balance between oxidants and antioxidants is disturbed so that antioxidants cannot compensate for the harmful effects of oxidants. Due to the high concentration of oxygen and hemoglobin in red blood cells (RBCs), these are among the first cells exposed to oxidative damage. When RBCs are exposed to oxidative stress, their hemoglobin is oxidized, and lipid peroxidation leads to membrane instability, deformation, hemolysis, and anemia. Oxidative stress has a fundamental role in the pathogenesis of these parasites. In the present review article, we collected studies on the oxidative stress caused by Piroplasmida in domestic animals. What is obtained from the total review of studies conducted on piroplasmosis revealed that in these infections, the host faces oxidative stress, and the resultant oxidative injury plays a fundamental role in their pathogenicity. Further studies are needed to be carried out on the more precise role of oxidative stress, the use of more sensitive diagnostic biomarkers, and the possible therapeutic role of antioxidant agents in piroplasmosis.

Virulence of Babesia bigemina in infected cattle (Bos taurus): Molecular and immunological studies

This study examined 400 tick-infested cattle from the following four governorates in Egypt: Faiyum, Beni Suef, Giza, and Minya. These cattle were examined for blood parasites between January 2021 and April 2022. The infected cattle were classified into four groups based on tick infestations and clinical signs. Blood was drawn for assessing oxidative stress markers as well as for parasitological examination and molecular analysis of the 18S rRNA gene of Babesia bigemina (B. bigemina). We performed a comparison of the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) between B. bigemina-infected blood samples and non-infected blood samples used as negative controls. Babesia spp. infection increases hemolysis, which in turn increases oxidative stress marker levels and cell-mediated immune response.

Integration of DNA Repair, Antigenic Variation, Cytoadhesion, and Chance in Babesia Survival: A Perspective

Apicomplexan parasites live in hostile environments in which they are challenged chemically and their hosts attempt in many ways to kill them. In response, the parasites have evolved multiple mechanisms that take advantage of these challenges to enhance their survival. Perhaps the most impressive example is the evolutionary co-option of DNA repair mechanisms by the parasites as a means to rapidly manipulate the structure, antigenicity, and expression of the products of specific multigene families. The purpose of variant proteins that mediate cytoadhesion has long been thought to be primarily the avoidance of splenic clearance. Based upon known biology, I present an alternative perspective in which it is survival of the oxidative environment within which Babesia spp. parasites live that has driven integration of DNA repair, antigenic variation, and cytoadhesion, and speculate on how genome organization affects that integration. This perspective has ramifications for the development of parasite control strategies.

Evaluation of cardiovascular biomarkers and histopathological alterations in cattle naturally infected by Babesia bigemina

Hemolytic anemia and secondary hypoxia are characteristics of naturally occurring Babesia bigemina infection in cattle. The anemic phase comes with cardiovascular insufficiency due to hypoxia-induced system dysfunction; but to date there is no description of cardiac damage in the infected animals. Therefore, this study was undertaken to investigate hematological parameters, biomarkers of cardiac function and D-dimer in 13 cattle infected with B. bigemina which were unresponsive to standard treatment. The animals were necropsied and the cardiac tissue was examined for histopathologic alterations. A significant parasitemia burden-dependent increase in the cardiac biomarkers and D-dimer level were recorded in the infected cattle compared to the control animals. Thrombocytes count was also significantly lower in the infected animals than the control. Both macroscopic and microscopic hemorrhage, mononuclear infiltrates, and myocardial necrosis were the evident histopathologic findings. These findings suggest that B. bigemina infection can potentially induce cardiac dysfunction in cattle. Furthermore, mechanistic studies should be conducted to understand the mechanisms beyond cardiac complications.

Assessment of hepatic oxidative damage, paraoxonase-1 activity, and lipid profile in cattle naturally infected with Ba7besia bigemina

Naturally occurring Babesia bigemina infection in cattle is associated with changes in the status of oxidative stress, trace elements, sialic acid, and cholinesterase activity in blood. However, to date there is no description of hepatic damage in the infected animals. More importantly, the majority of the above-mentioned causative factors are synthesized or stored in the liver. Therefore, this study was undertaken to evaluate biomarkers of hepatic function, paraoxonase-1 activity, and lipid profile in 13 cattle infected with B. bigemina which did not respond to standard treatment. The animals were necropsied and the histopathology of the liver and DNA damage of hepatocytes were examined. Blood analysis revealed a significant parasitemia burden-dependent increase in the activities of hepatic enzymes and total bilirubin and a decrease in albumin concentrations in the infected cattle compared to the control ones. Paraoxonase-1 activity was remarkably lower in the infected animals than the control. A significant decrease in the blood concentrations of total cholesterol, low density lipoprotein, and high density lipoprotein and a significant increase in the triglyceride concentration were observed in the infected animals. Severe oxidative damages were also recorded in the haptic tissue evidenced by significant alterations in the activities of antioxidant enzymes, suppression of total antioxidant capacity, and oxidation of biomolecules. Congestion of blood vessels, bile duct hyperplasia, and hepatocyte necrosis were the evident histopathologic findings. Our results revealed significant changes in the indices of liver function in the diseased cattle, leading to the conclusion that the parasite can potentially cause liver dysfunction.

Evaluation of some acute phase proteins in cattle naturally infected with Babesia bigemina

Bovine babesiosis due to Babesia bigemina infection induces systemic inflammation, evidenced by increased sialic acid (SA) levels and declined cholinesterase activity. The current study was undertaken to assess further indicators of the systemic inflammation in the naturally infected cattle. To this end, serum levels of some selected acute phase-proteins (APPs) including serum amyloid A (SAA), haptoglobin (Hp), ceruloplasmin (Cp), and fibrinogen were measured. Additionally, sensitivity and specificity of the APPs were calculated by receiver operating characteristic curve. The correlation among APPs, SA and cholinesterase activity were also assessed. Our previous blood specimens were used to measure APPs. Briefly, the diseased animals were divided into two groups according to the parasitemia: 12 mildly (20 % <) and 8 severely (20 %>) infected animals. Moreover, 10 healthy animals as the control were included. The levels of all APPs were measured to be significantly elevated in a parasitemia burden-dependent fashion as compared to the control. Furthermore, all the APPs showed 100 % specificity, but only SAA and Cp had 100 % sensitivity. A strong and positive correlation was calculated between the APPs and SA; however, cholinesterase activity was inversely correlated with AAPs and SA. In conclusion, inflammatory reactions play a pivotal role in the pathogenesis of bovine babesiosis and APPs can be considered as the potential indicators of inflammation.

Elevated serum manganese concentration in dogs as a possible predisposing factor of cerebral babesiosis in dogs

The aim of this study was to demonstrate a relationship between the occurrence of clinical signs of brain involvement in dogs with babesiosis and the concentration of manganese (Mn) in their serum. The study included seven dogs with early babesiosis (Group 1), seven dogs with cerebral babesiosis (Group 2) and seven healthy dogs (Group 3). Haematological and biochemical blood tests were performed in all dogs, and the results were analysed statistically. The Mann-Whitney rank test was used to demonstrate the differences in Mn concentrations, as well as other haematological and biochemical parameters between groups. In dogs in Group 2 with cerebral babesiosis, as compared to dogs in Groups 1 and 3, a statistically significant increase in serum Mn concentration was shown (P = 0.002 and P = 0.029) that may have been associated with the development of anaemia and/or impairment of liver function. Given the well-established neurotoxic effects of Mn in humans, experimental rodents and primates, additional studies on the role of Mn in the pathogenesis of the cerebral form of canine babesiosis are warranted.