Chippiparai is an indigenous hound dog breed of Southern Tamil Nadu with solid single coloured version used mainly for hunting purpose. It is generally sturdy to cope up the diseases, but under immune suppression due to tumor, even mongrels too vulnerable to haemoparasitic diseases. In tropical and sub-tropical regions, tick borne haemoprotozoan diseases were more common. The hot and humid environmental temperature favours the growth, development and multiplication of ticks. The brown dog tick
Rhipicephalus sanguineus is the common vector for both
H. canis and
B. canis (
Shyma et al., 2019)
. Canine hepatozoonosis is a blood protozoan disease caused by the ingestion of the infected
Rhipicephalus sanguineus tick not by the biting of the ticks because the infective stages don’t reach salivary glands of the vectors
(Baneth et al., 2001). Babesia species often referred to as piroplasms comprises two main species,
B. canis and
B. gibsoni, based on their size.
B. canis is a large piroplasm (4-5 5µm), which usually occurs as a single pear-shaped piroplasm or in pairs of merozoites divided by binary fission within the erythrocyte. The clinical signs of
Babesia canis can be subacute to acute and maybe fatal with pyrexia, splenomegaly, haemolytic anaemia and thrombocytopaenia are typical clinical findings (
Irwin, 2009).
The diagnosis of canine babesiosis is routinely done through direct microscopic examination of the Giemsa stained blood smear. It is the most commonly used method as this is conclusive, feasible and cost effective diagnostic method but not necessarily detects parasites in dogs with inapparent or chronic infections since the level of parasitemia is very low.
B. canis infections are common in Chennai, either individually or as concurrently with
E. canis or
H. canis (Harikrishnan et al., 2008).
Transmissible venereal tumor (TVT) is a reticuloendothelial tumor in dogs that mainly affects the external and internal genitalia as well as extragenital form also recorded. TVT was well diagnosed in the impression cytology
(Ganguly et al., 2013). The possible extent of co-infection could be due to myeloperoxidase deficiency in
H. canis infected neutrophils or due to immunologic alterations because of mixed infection
(Ibrahim et al., 1989). The objective of this work is to describe in detail about the clinico-pathological diagnosis of TVT with
H.
canis and
B. canis in a Chippiparai dog.
A male Chippiparai of 4.5 years old was brought to Veterinary Clinical Complex, Veterinary College and Research Institute, Tirunelveli during the April 2019, withthe history of swelling at the tip of the penis with continuous dribbling of blood, weakness, dullness and depression. On thorough clinical examination, the animal had pedunculated mass at the tip and base of the penis along with presence of ticks on the body. The touch impression cytology was taken from the penile mass. Blood samples were collected in K
3 EDTA vials and Clot activator for the haematology and biochemical analysis respectively. The whole blood was analysed by auto haematology analyzer (3 part celenium junior, Trivitron) and serum in semi-automated biochemical analyzer (Lab mate) by spectrophometerically using standard diagnostic kits. The tissue impression smears were stained with Leishman stain and the blood smear was stained with Leishman-Giemsa combination for better viewing of cellular details and for the parasitic examination. After confirming TVT with impression cytology, the animal underwent chemotherapy for the TVT with the standard protocol of Vincristine treatment and standard therapeutic protocol for the haemoprotozoan parasites of dogs.
On gross examination, the tumor was cauliflower like, pedunculated mass at the base of the penis region of the dog, which was in accordance with the observation of
Ganguly et al., 2013. The TVT in dogs are not only transmitted by coitus, but also by licking, sniffing and biting of the tumor area or through the damaged skin and mucosa. In a study by
Shiju simon et al., 2016, recorded the incidence of genital TVT was about 97.13 percent and Extra genital TVT as 21.58 percent in Chippiparai breeds of dogs. The cytological findings of the impression smear from the penile mass were suggestive of transmissible venereal tumor. The cytology revealed the presence of uniform sheets of discrete round cells with large round eccentric nuclei showing granular chromatin pattern and prominent nucleolus (Fig 1). The neoplastic cells have clear, distinct round cell borders with multiple punctuate vacuolation in the moderately blue staining cytoplasm (
Valenciano and Cowell, 2014). Mitotic figures in various stages, numerous neutrophils and moderate amount of RBCs were seen
(Cingi et al., 2020).
The Hematological and serum biochemical values are given in the Table 1. Hematological examination showed marked reduction in hemoglobin, packed cell volume, red blood cell count, platelet count and increase in total whiteblood cell count. The blood picture revealed the presence of neutrophilia, codocytes and hypochromasia. Further the blood smear revealed concurrent presence of
Hepatozoon canis (++++) gamont in neutrophils and
Babesia canis (+++) piroplasms in red blood cells (Fig 2). In this study, completeblood count revealed normocytic and hypochromic anaemia with neutrophillia as observed by
Balachandran et al., 2010 and
Paramjit et al., 2012 except the comorbid infection
H. canis and
B. canis. The presence of combined infection may be due to sharing of the brown dog tick
Rhiphicephalus sanguineus as a common vector. In general,
H.canis infection affects the spleen, lymph nodes and bone marrow with the clinical signs of asymptomatic, mild or severe anaemia and lethargy depending upon the parasitemia and the immune status of animal.
H. canis is often found in association with other infections including blood parasites
(Harikrishnan et al., 2008).
The reduction in the hematological values might due to the proliferation of piroplasms in RBCs and continuous blood loss from the genital TVT. The reduction in platelet count was described by
Brown et al., (2006), that thrombocytopenia in concurrent infection could be due to increased platelet consumption in blood vessel endothelium, increased splenic sequestration of platelets and immunologic destruction or injury with a decreased platelet life span. The anaemic blood picture like leucocytosis, neutrophilia, hypochromasia, anisocytosis and codocytes were recorded. It occurs in most of the inflammatory condition and in tumors due to interaction of fibrinogen with sialic acid on the surface of RBCS
(Senthil et al., 2015).
The serum biochemical values showed the elevation of alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen, creatinine and reduction of total protein, albumin. The increase in ALT and ALP might be due to liver damage by the
Babesia canis and progression of schizogony of
Hepatozoon canis in bone marrow and spleen respectively
(Sarma et al., 2012). Hypoproteinemia with hypoalbuminemia could be due to peripheral loss fluids in inflammatory condition as a result of increased vascular permeability, blood loss or decreased plasma production due to concurrent hepatopathy that occurred with the disease
(Harrus et al., 1997). The increase in BUN and Creatinine value due to infiltration of parasites in glomeruli of kidney causing glomerulonephritis
(Harikrishnan et al., 2008).
Several treatments including surgical excision, radiotherapy, immunotherapy and chemotherapy have been used to treat the TVT but chemotherapy has been shown to be the most effective and easily available practical therapy. The chemotherapeutic agents such as vincristine, vinblastine, doxorubicin and cyclophosphamide have been used
(Otter et al., 2015). In this case, vincristine sulphate was administered intravenously (0.025 mg/kg BWT) at weekly intervals for 5 weeks along with specific treatment for the
H. canis and
B. canis was followed as per
Varshney et al., 2009. The size of the tumor were reduced markedly after the fourth cycle of treatment in the first week of May’ 2019 and the blood smear examination also revealed the absence of
H. canis gamont and
B. canis piroplasms.
