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BACKGROUND CASE PRESENTATION Canine Hepatozoonosis is a tickborne disease caused by Five dogs aged between five months to seven years apicomplexan haemoprotozoan parasites of the Genus recently diagnosed with different disease conditions Hepatozoon. Two species of hepatozoons, namely presented to Veterinary Teaching Hospital, Peradeniya Hepatozoon canis (H. canis) and Hepatozoon with paresis, chronic emaciation, muscular pain, had americanum (H. amaricanum) are known to infect dogs Hepatozoon like gamonts (4-12%) in the peripheral (Baneth et al., 2003). Of these two species, H.canis circulation. Though H.canis is commonly known to cause transmitted by the brown dog tick Rhipicephalus clinically inapparent infection, the clinical sanguineus is reported in Asian countries whereas H. manifestations, haematological parameters, serum amaricanum transmitted by Amblyomma maculatum is alkaline phosphate (ALP) levels and response to treatment limited to Southern United States. Comparatively, latter is of those five patients were evaluated to identify the factors known to cause severe infection characterized by which complicated the clinical presentation. exostosis and myositis (Vincent-Johnson et al. 1997). Signalements, clinical manifestations and the medical history of the five patients are given in Table 1. When first recognized in India in 1905, it was believed that H. canis only cause a milder disease resulting in Two of the five patients (patient 1 and 2) had been anaemia and lethargy (Vincent-Johnson et al. 1997). recently treated with immunosuppressive doses of However, it was later found out that certain factors corticosteroids. Third patient was on long-term including immunosuppression and co-infections can lead antimicrobial therapy (over five months) and the fourth to severe clinical manifestations due to Hepatozoonosis. A patient was on long term pancreatin. More than 4% (4n u m b e r o f n o n s p e c i f i c h a e m a t o l o g i c a l a n d 12%) of the neutrophils in peripheral blood contained haemochemical changes including non-regenerative capsule like gamonts (Figure 1). Multiplex polymerase a n a e m i a , t h r o m b o c y t o p e n i a , n e u t r o p h i l i a , chain reaction (PCR) was performed as described in hyperproteinaemia, hypoalbuminaemia, polyclonal Kledmanee et al. (2009) in order to determine whether the gammopathy, and elevated serum creatine kinase (CK) clinical complications were due to concurrent infection and alkaline phosphatase (ALP) have been seen in dogs with Ehrlichia canis or Babesia species. Electrophoresis infected with H. canis (O'Dwye et al., 2006). The of PCR amplicons confirmed Hepatozoon canis as the detection of capsule-like gammonts in the cytoplasm of Hepatozoon species observed in peripheral blood and the the neutrophils in blood smears is routinely used to dogs were not concurrently infected with E. canis or diagnose hepatozoonosis. Molecular diagnostic Babesia (Figure 2). techniques, such as polymerase chain reaction (PCR) and sequencing are important for species ...

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INTRODUCTION (Gershwin et al., 1995). A deficiency or a malfunction at any stage of neutrophil function can impair the ability of The Innate immunity is the first line of defense in the an animal to overcome an infection (Gershwin et al., body which includes physical and chemical barriers; 1995). Severe sepsis in diseases may alter innate circulating effector cells [phagocytes and natural killer imm une def ens es, dis rup t mic rob ial cle ara nce cells (NK)], complement proteins and cytokines (Abba, mechanisms, and complicate the pathophysiology of 2007). Intact skin and its secretions are impermeable to sepsis. Septic shock itself has significant effects upon most infectious agents and act as major physical barriers the innate and adaptive host immune responses ge ne ra ti ng th e fi rs t li ne of de fe ns e. T ho se contributing to a state of sepsis-induced immune microorganisms that evade the epithelial barrier get dysregulation (Opal and Cross, 2005). Although killed by natural antimicrobial peptides, but many get congenital or inherited immunodeficiency disorders are engulfed and killed by phagocytes (Tizard, 2009; Roitt, uncommon in the dog, immunodeficiency secondary to 1988). Phagocytosis is an active process in phagocytic a wide range of causes (e.g., age, drug therapy, and le uk oc yt es , na me ly, ne ut ro ph il s, eo si no ph il s, chronic neoplastic or infectious disease) is relatively monocytes, and macrophages. Neutrophils are the first comm on in adul t dogs. Most cani ne immu ne resp onde rs th at ph agoc ytiz e and kill inva ding deficiencies are breed-related. Aged Beagle dogs have pathogens (Abba, 2007). Phagocytosis of cytokine decreased neutrophil phagocytosis and neutrophilactivated neutrophils and their microbicidal activities related gene expression compared to younger dogs are the first line of cellular defense against invading (Hall et al., 2010) pathogens, and are a major part of innate immunity Neutrophil phagocytosis can be measured by several (Silva et al. 1988). methods by allowing bacteria, yeast, or other particles Phagocytic activity is a continuous process involving and neutrophils to interact, and then to measure the discrete stages occurring in a sequential manner, number of neutrophils that have ingested particles, as namely, cell activation, chemotaxis, adherence, well as the phagocytic index determined by the average ingestion, and destruction (Tizard, 2009). The factors number of organisms within a phagocyte (Kaneko and influencing phagocytic properties of cells include cell Harvey, 1997; Gershwin et al., 1995). A phagocytosis age, energy (ATP), and integrity of cellular skeleton assay of canine blood neutrophils for bacteria is a long such as microfilaments and microtubules (Jain, 1986). felt need to identify immune compromised dogs. The The important properties of bacteria influencing objective of this research was to establish an in vitro ph ag oc yt os is ar e su rf ac e ch ar ge s, ce ll wa ll phagocytic assay for blood neutrophils isolated from composition, capsu...

Canine parvovirus (CPV) is the main cause of gastroenteritis and mortalities in young dogs worldwide. Despite vaccination, the outbreaks of canine parvovirus infection occur in many countries including Sri Lanka. Interference caused by maternally derived antibodies (MDA) is a main reason for vaccination failure. Present study assessed the level of CPV specific MDA in puppies prior to vaccination, the effect of MDA on the efficacy of different preparations of CPV vaccines and, evaluated the immunogenicity of selected CPV vaccines available commercially. Analysis of MDA in puppies born to vaccinated or unvaccinated mothers using commercially available point of care ELISA based test revealed the presence of protective levels of MDA titres at 8 weeks of age which can affect the immunogenicity of the vaccines containing inactivated virus or low viral titre (1000 HAU). 3-5The vaccines containing CCID 50 of ≥10 were able to induce antibody titres higher than protective level. Analysis of CPV-2 specific antibody titres, two weeks after completing the primary CPV vaccination (16-18 weeks of age) revealed that the dogs who received the 5 vaccines containing CPV-2 or CPV-2b strain with >10 CCID 50 induced significantly high levels of mean antibody titre (vaccine "B"-p value = 0.004; vaccine "D" -p value = 0.022; vaccine "F"-p value = 0.032) when compared to the vaccine containing 1000 HAU. In conclusion, it was evident that the interference of MDA on CPV vaccines could be circumvented by using a live attenuated CPV vaccine having a high viral dose of CPV. Low viral dose vaccines and inactivated vaccines are not suitable for primary vaccination as those could be interfered by maternal immunity