Canine babesiosis in South Africa: more than one disease. Does this serve as a model for falciparum malaria

Abstract

South African canine babesiosis is caused by the virulent Babesia canis rossi. In recent years, this common disease has been detected in 12% of dogs presented at the outpatients' division of the University of Pretoria's (Onderstepoort) Veterinary Academic Hospital, and 31% of the affected dogs have been hospitalized as seriously ill. Of these hospitalized cases, 50% had severe anaemia at presentation, 32% had moderate anaemia and 18% were non-anaemic (often polycythaemic), frequently with central-nervous-system signs or multiple organ failure. A retrospective survey of 662 hospitalized cases revealed that the haematology, clinical biochemistry and patient profile (signalment) of the severely anaemic dogs were distinct from those of the non-anaemic, indicating that the babesiosis in these two groups of dogs should be viewed as two different disease in terms of the postulated, underlying, 'pathomechanisms'. The severely anaemic dogs exhibited hypoxic hepatic disease and an increase in serum urea (without a concomitant increase in creatinine), seldom had profound electrolyte imbalances and tended to have a much more profound leucocytosis, consisting of a left-shifted inflammatory leucogram, with higher numbers of circulating metamyelocytes, lymphocytosis and monocytosis. In contrast, the non-anaemic dogs exhibited severe azotaemia (which could be of renal or pre-renal origin) and often showed a marked electrolyte disturbance (reflecting acid-base abnormalities) and a very mild leucocyte response; such dogs often presented as leucopenic, many being lymphocytopenic. These results indicate that the severely anaemic dogs had developed haemolytic disease (possibly immune-mediated), whereas the non-anaemic dogs had developed an acute and overwhelming inflammatory response. The mean age of the non-anaemic dogs (2.66 years) was less than the dogs in the 'severe anaemia group' (0.83 years). Dogs belonging to the traditional fighting breeds (bull terriers, pit bull terriers and Staffordshire bull terriers) were noticeably over-represented in the non-survivors of the acute inflammatory response, possibly indicating an underlying genetic basis for the different presentations. It is evident that the inflammatory-response disease presentation, which is similar to complicated falciparum malaria in humans, amy serve as an animal model for the disease.

Identification of serum biomarkers in dogs naturally infected with Babesia canis canis using a proteomic approach

“…Our findings confirmed two dominant pathogenic mechanisms of babesiosis, haemolysis and acute phase response [52,53]. The role of haemolysis in the course of babesiosis was demonstrated by haptoglobin, hemopexin and serotransferrin expression changes.…”

Serum canine pancreatic-specific lipase concentrations in dogs with naturally occurring <i>Babesia rossi</i> infection

“…A study examining serum cPL concentration in dogs with ehrlichiosis found 20% of dogs with natural infection had results consistent with the diagnosis of acute pancreatitis; however, none of the dogs displayed specific gastrointestinal signs, only nonspecific clinical signs, including anorexia and depression (Mylonakis et al 2014 ). The virulent form of canine babesiosis shares many similarities with human malaria caused by Plasmodium falciparum and therefore the naturally acquired infection in dogs has been proposed as an animal model for this disease (Reyers et al 1998 ). A number of case reports describe acute pancreatitis as a complication of this type of malaria in humans (Johnson, DeFord & Carlton 1977 ; Kumar, Jain & Vikas 2010 ; Mandal et al 2011 ; Mohapatra & Gupta 2011 ; Sarma & Kumar 1998 ; Seshadri et al 2008 ; Thapa, Mallick & Biswas 2010 ; Trowers et al 1992 ).…”

“…The virulent form of canine babesiosis, caused by Babesia rossi , is associated with various complications, including acute kidney injury, cerebral babesiosis, disseminated intravascular coagulation, hepatopathy, immune-mediated haemolytic anaemia, acute respiratory distress syndrome (ARDS), haemoconcentration, shock and pancreatitis (Defauw et al 2012 ; Jacobson & Clark 1994 ; Lobetti & Jacobson 2001 ; Mohr, Lobetti & Van der Lugt 2000 ; Köster et al 2009 ; Reyers et al 1998 ; Schoeman 2009 ; Welzl et al 2001 ).These complications are proposed to be the result of SIRS that is present in most cases of canine babesiosis, which could progress to multiple organ dysfunction syndrome (Welzl et al 2001 ). The development of SIRS in dogs with a variety of diseases is associated with significantly higher mortality (18.8% versus 5.3%) (Okano et al 2002 ).…”

The Effect ofBabesia divergensInfection on the Spleen of Mongolian Gerbils

“…This early change was hypothesized to be caused by hemodilution, splenomegaly, and sequestration in the spleen [28]. This mechanism may include autoimmune haemolysis [29], reduced red cell deformability [30], and increased oxidative damage [27, 31]. Also, numerous studies have demonstrated that a variety of inflammatory cells are induced or activated by various oxidant-generating enzymes to kill intracellular and extracellular parasites [26].…”