Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review.

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Pathogenesis of Anemia in Canine Babesiosis: Possible Contribution of Pro-Inflammatory Cytokines and Chemokines-A Review.

Canine babesiosis is a tick-borne protozoan disease caused by intraerythrocytic parasites of the genus Babesia. The infection may lead to anemia in infected dogs. However, anemia is not directly caused by the pathogen. The parasite's developmental stages only have a marginal role in contributing to a decreased red blood cell (RBC) count. The main cause of anemia in affected dogs is the immune response to the infection. This response includes antibody production, erythrophagocytosis, oxidative damage of RBCs, complement activation, and antibody-dependent cellular cytotoxicity. Moreover, both infected and uninfected erythrocytes are retained in the spleen and sequestered in micro-vessels. All these actions are driven by pro-inflammatory cytokines and chemokines, especially IFN-γ, TNF-α, IL-6, and IL-8. Additionally, imbalance between the actions of pro- and anti-inflammatory cytokines plays a role in patho-mechanisms leading to anemia in canine babesiosis. This article is a review of the studies on the pathogenesis of anemia in canine babesiosis and related diseases, such as bovine or murine babesiosis and human or murine malaria, and the role of pro-inflammatory cytokines and chemokines in the mechanisms leading to anemia in infected dogs.

Association between Increased the De Ritis Quotient and Renal Azotaemia in Canine Babesiosis.

Previous studies of azotaemia in canine babesiosis revealed pre-renal and renal azotaemia in infected dogs, and an association between an increased de Ritis quotient (aspartate aminotransferase to alanine aminotransferase activity; AST/ALT ratio) and azotaemia in affected animals. Serum activities of AST and ALT, and AST/ALT ratio were compared between azotaemic and non-azotaemic dogs infected with Babesia canis, and between affected dogs with pre-renal and renal azotaemia. Statistical analyses revealed higher AST activity and an increased AST/ALT ratio in azotaemic dogs, and an increase of these two parameters in infected dogs with renal azotaemia in comparison to dogs with pre-renal azotaemia. Moreover, AST activity and AST/ALT ratio were correlated with renal indices such as renal failure index, sodium fractional excretion, and urinary creatinine to serum creatinine ratio. The study also revealed a lack of correlation between AST and ALT activities in azotaemic dogs, although a correlation was observed when including all dogs in this study (azotaemic and non-azotaemic dogs treated as one group). The results of this study indicate that increased serum AST activity in azotaemic dogs infected with B. canis may have a renal origin, and the AST/ALT ratio could be considered as a simple and convenient renal index that is useful in the recognition of renal azotaemia in canine babesiosis.

Disorders in Blood Circulation As a Probable Cause of Death in Dogs Infected with Babesia Canis.

INTRODUCTION: The purpose of the study was to investigate post-mortem changes in dogs infected with Babesia canis and to establish the probable cause of death of the affected animals. MATERIAL AND METHODS: Cadavers of six dogs that did not survive babesiosis were collected. Necropsies were performed and samples of various organs were collected for histological examination. RESULTS: Necropsies and histological examinations revealed congestion and oedemata in various organs. Most of the dogs had ascites, hydrothorax or hydropericardium, pulmonary oedema, pulmonary, renal, hepatic, and cerebral congestion, and necrosis of cardiomyocytes. CONCLUSION: These results suggested disorders in blood circulation as the most probable cause of death. However, the pulmonary inflammatory response and cerebral babesiosis observed in some of these dogs could also be considered possible causes of death. This study also showed a possible role for renal congestion in the development of renal hypoxia and azotaemia in canine babesiosis.

Hyponatraemia and Syndrome of Inappropriate Antidiuretic Hormone Secretion in Non-azotaemic Dogs with Babesiosis Associated with Decreased Arterial Blood Pressure.

INTRODUCTION: A previous study on canine babesiosis showed low serum tonicity in affected dogs, which may result from syndrome of inappropriate antidiuretic hormone secretion (SIADH). This endocrine disorder was recognised in human malaria which is considered a disease with similar pathogenesis to canine babesiosis. The aim of this study was to investigate the occurrence of SIADH in babesiosis-afflicted dogs. MATERIAL AND METHODS: Serum and urinary sodium and urine specific gravity (USG) were determined in dogs with babesiosis. Mean arterial pressure (MAP) was measured at the beginning of the clinical examination. Serum tonicity and osmolality were calculated. Correlations were calculated between MAP and serum and urinary sodium concentrations, USG, serum tonicity, and calculated serum osmolality. RESULTS: Statistically significant correlations were observed between MAP and tonicity, calculated osmolality, USG, and serum and urinary sodium concentrations in non-azotaemic dogs. In three non-azotaemic dogs SIADH was recognised. CONCLUSION: SIADH develops in non-azotaemic dogs with babesiosis. It is probably associated with decreased blood pressure in infected dogs. Thus, it seems that in fact it may be appropriate vasopressin secretion in canine babesiosis as a protective mechanism in hypotension which leads to hypoxia and renal failure in affected dogs.

The first case of Leporacarus gibbus infestation in a rabbit from Poland.

This case report presents asymptomatic infestation with Leporacarus gibbus (formerly Listrophorus gibbus) in a pet rabbit. This is the first report of L. gibbus infestation in a pet rabbit from Poland. Previously, infestation in Poland had been detected only in hares.

Low T3 syndrome in canine babesiosis associated with increased serum IL-6 concentration and azotaemia.

Low triiodothyronine (T3) syndrome, also named euthyroid sick syndrome or non-thyroidal illness syndrome, has been recognized in canine babesiosis caused by Babesia rossi, where it manifested by lowering of the serum thyrotropin (TSH), total thyroxin (TT4) and free thyroxin (FT4) concentrations. This syndrome has also been observed in critical diseases in humans and animals, and the severity of the disease is considered an important factor in lowering of thyroid hormone concentrations. Interleukin-6 (IL-6) plays a role in the development of low T3 syndrome by causing a decrease in deiodinases 1 and 2 activity and increased activity of deiodinase 3, enzymes involved in the conversion of thyroxin (T4) to T3. The purpose of this study was to compare the concentrations of serum thyroid hormones and TSH between healthy dogs and dogs with babesiosis, and to determine correlations between serum IL-6 concentration and serum total T3 (TT3), TT4, FT4, and TSH concentrations, and the level of azotaemia in dogs with babesiosis. The concentrations of IL-6, TT3, TT4, FT4, TSH, urea and creatinine were determined in 13 dogs with canine babesiosis caused by Babesia canis and in 10 healthy dogs. The results of this study showed decreases in TT3, TT4, FT4, and TSH and increases in IL-6, urea and creatinine concentrations in affected dogs in comparison to healthy dogs. The concentration of IL-6 was negatively correlated with TT3 and TSH concentrations and the TT3 concentration was negatively correlated with serum urea and creatinine concentrations. This study showed low T3 syndrome in canine babesiosis, which was confirmed by the determination of the T3 concentration, and demonstrates that in canine babesiosis the T3 concentration is associated with IL-6 concentration.

Hyperaldosteronism and its association with hypotension and azotaemia in canine babesiosis.

BACKGROUND: The previous work on canine babesiosis revealed hypokalaemia and increased fractional excretion of potassium in infected dogs suggesting a role for aldosterone in the loss of potassium via the kidneys in affected dogs. Moreover, hypotension, which is one of the complications of canine babesiosis leading to renal failure, may induce secondary hyperaldosteronism. ANIMALS AND METHODS: In this study, the serum aldosterone concentration was determined in 14 dogs infected with Babesia canis. The Mann-Whitney U test was used to compare serum aldosterone concentration and blood pressure between these dogs and 10 healthy dogs. Spearman's rank correlations between serum aldosterone concentration and blood pressure and between serum aldosterone and urea and creatinine concentrations were calculated. RESULTS: Increased concentrations of aldosterone above reference intervals were observed in only 4 out of the 14 dogs. The results showed significantly (p < 0.05) higher serum aldosterone concentrations and lower blood pressures in infected dogs in comparison to healthy dogs, and significantly negative correlations between aldosterone concentration and systolic arterial pressure (r = -0.63), diastolic arterial pressure (r = -0.67) and mean arterial pressure (r = -0.65). Serum aldosterone concentration was also significantly correlated with serum urea concentration (r = 0.72), serum creatinine concentration (r = 0.69) and serum potassium concentration (r = -0.57). CONCLUSION: The results of this study show hyperaldosteronism in some cases of canine babesiosis as a possible response to hypotension. However, both the hypotension and severe azotaemia observed in dogs infected with B. canis and associated hyperaldosteronaemia suggest that this response is insufficient.

Increased serum urea to creatinine ratio and its negative correlation with arterial pressure in canine babesiosis.

The increase of the serum urea to creatinine ratio (UCR) was observed in dogs infected with Babesia canis. Previous studies have suggested that decrease of blood pressure can be one of the reasons for this phenomenon. In this work statistically significant increase of the UCR was observed in dogs with babesiosis. Comparison of the UCR between 23 azotaemic dogs and 25 non-azotaemic dogs infected with Babesia canis showed statistically significantly higher mean of the UCR in azotaemic dogs. Correlations between UCR and systolic, diastolic and mean arterial pressure (SAP, DAP and MAP) in 48 dogs infected with B. canis were negative (UCR and SAP: r = -0.3909; UCR and DAP: r = -0.3182; UCR and MAP: r = -0.3682) and statistically significant (p < 0.05). This result may indicate contribution of hypotension in the increase of the UCR in canine babesiosis. However, the correlations were not high, and there was no statistically significant correlation between UCR and arterial pressures in azotaemic dogs. Thus, it seems that decrease of blood pressure in dogs with babesiosis explains only partially the cause of increased UCR in infected dogs. The other authors suggested hyperureagenesis and myocardial injury as a potential reason for the increased UCR in canine babesiosis. Thus, further studies are needed to determine causes of increased UCR in dogs with babesiosis, especially on the connection between UCR changes and the concentrations of plasma cardiac troponins and ammonia, and the occurrence of occult blood on fecal examination.

Increased concentration of serum TNF alpha and its correlations with arterial blood pressure and indices of renal damage in dogs infected with Babesia canis.

Canine babesiosis is a tick-borne disease caused by parasites of the genus Babesia. Tumour necrosis factor alpha (TNF-α) is a cytokine that plays a role in the pathogenesis of canine babesiosis. In this study, the authors determined the concentration of serum TNF-α in 11 dogs infected with Babesia canis and calculated Spearman's rank correlations between the concentration of TNF-α and blood pressure, and between TNF-α and indices of renal damage such as: fractional excretion of sodium (FE(Na(+))), urinary creatinine to serum creatinine ratio (UCr/SCr), renal failure index (RFI), urine specific gravity (USG) and urinary protein to urinary creatinine ratio (UPC). The results demonstrated statistically significant strong negative correlations between TNF-α and systolic arterial pressure (r = -0.7246), diastolic arterial pressure (r = -0.6642) and mean arterial pressure (r = -0.7151). Serum TNF-α concentration was also statistically significantly correlated with FE(Na(+)) (r = 0.7056), UCr/SCr (r = -0.8199), USG (r = -0.8075) and duration of the disease (r = 0.6767). The results of this study show there is an increase of serum TNF-α concentration during canine babesiosis, and the increased TNF-α concentration has an influence on the development of hypotension and renal failure in canine babesiosis. This probably results from the fact that TNF-α is involved in the production of nitric oxide and induction of vasodilation and hypotension, which may cause renal ischaemia and hypoxia, and finally acute tubular necrosis and renal failure.

Urinary creatinine to serum creatinine ratio and renal failure index in dogs infected with Babesia canis.

Urinary creatinine to serum creatinine (UCr/SCr) ratio and renal failure index (RFI) are useful indices of renal damage. Both UCr/SCr ratio and RFI are used in differentiation between prerenal azotaemia and acute tubular necrosis. In this work the authors calculated the UCr/SCr ratio and RFI in dogs infected with Babesia canis and the values of these indices in azotaemic dogs infected with the parasite. The results of this study showed significantly lower UCr/SCr ratio in dogs infected with B. canis than in healthy dogs. Moreover, in azotaemic dogs infected with B. canis the UCr/SCr ratio was significantly lower and the RFI was significantly higher than in non-azotaemic dogs infected with B. canis. The calculated correlation between RFI and duration of the disease before diagnosis and treatment was high, positive and statistically significant (r = 0.89, p < 0.001). The results of this study showed that during the course of canine babesiosis caused by B. canis in Poland acute tubular necrosis may develop.

Functioning unilateral adrenocortical carcinoma in a dog.

An 11-year-old, 24-kg, intact female Siberian husky dog in anestrus had a 2-month history of polyuria and polydipsia. The dog had signs of mineralocorticoid excess such as hypertension and hypokalemia refractory to potassium supplementation. Abdominal ultrasound revealed an irregular mass in the left adrenal gland. The ACTH stimulation test for aldosterone concentration did not reveal hyperaldosteronism. Unilateral adrenalectomy was performed and histopathology identified adrenal cortical carcinoma. All clinical signs of mineralocorticoid excess ceased after surgery.

Strong monovalent electrolyte imbalances in serum of dogs infected with Babesia canis.

Canine babesiosis is a systemic tick-borne protozoan disease caused by infection with parasites of the genus Babesia. Acid-base disorders and ion imbalances have been described in dogs infected with Babesia rossi in South Africa. In this paper, the authors describe changes to monovalent ion concentrations and calculated parameters of monovalent ions in 70 dogs naturally infected with B. canis, a species occurring in Europe. Hyponatraemia, hypokalaemia, hyperchloraemia, decrease of chloride gap, strong ion gap, difference between sodium and chloride concentrations, and an increase of chloride-to-sodium and sodium-to-potassium ratios were the most prevalent changes. Hyponatraemia, hypokalaemia and hyperchloraemia were detected less frequently than in dogs infected with B. rossi, but the severity of these changes were similar. Comparison of monovalent ion concentrations in azotaemic and non-azotaemic, and anaemic and non-anaemic dogs infected with B. canis showed that azotaemic dogs had significantly lower sodium concentrations. The results of this study indicate a possible development of hyperchloraemic acidosis and the probable contribution of aldosterone in the development of hypokalaemia. However, further study on blood gas, aldosterone, and antidiuretic hormone in dogs infected with B. canis is needed.