Natural Besnoitia besnoiti infections in cattle: hematological alterations and changes in serum chemistry and enzyme activities

Abstract

BackgroundThe emerging disease bovine besnoitiosis is caused by the apicomplexan parasite Besnoitia besnoiti. Clinical signs of acute besnoitiosis are pyrexia, anorexia and subcutaneous edema. In subacute and chronic besnoitiosis parasitic cysts arise in a variety of tissues and affected cattle display skin lesions and weight loss. In all stages of bovine besnoitiosis, lesions can be found in many organ systems and therefore presumably alter a variety of laboratory parameters. In this study, the impact of naturally acquired acute, subacute and chronic bovine besnoitiosis on hematologic parameters, serum chemistry, and enzyme activities was investigated. Laboratory parameters of two Simmental heifers and two Limousin cows were monitored during acute, subacute and chronic besnoitiosis and in another Simmental heifer during subclinical besnoitiosis. To determine aberrations of laboratory parameters, values were compared with reference ranges obtained from B. besnoiti negative Simmentals (224 samples of nine animals) and Limousins (41 animals). Further, laboratory parameters of B. besnoiti seropositive Limousin cows (54 animals; 32 of these showing clinical signs) and healthy B. besnoiti seronegative Limousin cows (41 animals) were compared.ResultsDuring acute and subacute besnoitiosis, a reduction of leukocyte and erythrocyte concentrations, hematocrit, serum albumin, urea, magnesium, and calcium concentrations were observed. Serum total protein, globulin, total bilirubin and creatinine concentrations were increased and aspartate transaminase (AST) and creatine kinase (CK) activities were elevated. In chronic besnoitiosis, erythrocyte parameters were statistically significantly lower, and total protein and globulin concentrations were significantly higher in B. besnoiti seropositive compared with B. besnoiti seronegative Limousin cows.ConclusionsIn this study, altered laboratory parameters during the course of naturally acquired acute, subacute and chronic bovine besnoitiosis are described for the first time. Only a few animals were examined in acute and subacute besnoitiosis, however the alterations of laboratory parameters during these stages reflected i) the acute inflammatory state (e.g. high levels of serum globulin fractions), ii) clinical findings such as disturbed condition (e.g. bilirubin concentrations), and iii) lesions such as muscle necroses described in the literature (e.g. AST or CK activities). Chronic besnoitiosis led to typical alterations of chronic inflammatory diseases like hyper-(gamma)-globulinemia or reduced erythrocyte concentrations.

Effect of parasite dose and host age on the infection with Besnoitia besnoiti tachyzoites in cattle

“…Despite being a non‐specific lesion, target locations where vasculitis was found suggested that this might be a consequence of endothelial damage produced by the parasite during the acute phase. Similar lesions have been described under natural infection (Langenmayer et al., ). Focal degenerative lesions in testicle of the calves were observed only in relation to vasculitis that probably contributed to mild degenerative changes in the germinal epithelium.…”

“…However, the lesions observed in the reproductive tract were compatible with normal testicular function. Remarkably, in this study, a tissue cyst was located at the reticular dermis of the carpus region, a less frequent location than the papillary dermis (Langenmayer et al., ). As expected, a higher parasite intra‐organic distribution was found by PCR compared with histopathological results.…”

“…We only observed an increase in serum globulin fractions that was correlated with seroconversion in infected animals. There is only one previous study where haematological and biochemical alterations in sera were studied in B. besnoiti ‐seropositive cows during disease progression of naturally acquired bovine besnoitiosis (Langenmayer et al., ). Disturbances in Aspartate Aminotransferase or Creatine Kinase activities, and typical alterations of chronic inflammatory diseases such as hyper‐(gamma)‐globulinemia or reduced erythrocyte were described by these authors.…”

“…Biochemical and haematological analyses were performed according to procedures previously described (Langenmayer, Scharr, Sauter‐Louis, Schares, & Gollnick, ). They were analysed by comparing values from infected animals with bovine reference values, taking into account that values may vary due to age and environmental factors (George, Snipes, & Lane, ).…”

Naturally acquired bovine besnoitiosis: Disease frequency, risk and outcome in an endemically infected beef herd

“…Of 33 new clinical and 12 new serological cases, only 6.7% (3/45) were observed by the owner with clinical signs consistent with acute bovine besnoitiosis (separation from the herd, nasal/ocular discharge). Two of these cases were included in a separate cohabitation trial (as Study animals 20 and 22), details of disease course were described elsewhere (Langenmayer, Scharr, Sauter‐Louis, Schares, & Gollnick, ). The remaining animal separated from the herd in summer 2009 (between HC2 and HC3), showed nasal and ocular discharge and seroconverted shortly after clinical signs receded.…”