A Case of Parasitic Fibrino-necrotic Enteritis in A Rottweiler Dog

Diseases related primarily to gastrointestinal disturbances are common in small animal practice. Gastrointestinal diseases manifested by diarrhoea and/or vomition in dogs rank second after skin diseases (Bonagura and Twedt, 2008). Gastroenteritis/enteritis are the major inflammatory conditions of gastrointestinal tract and have wide variety of etiological origin mostly due to variety of infectious agents such as bacteria (Choudhary et al., 1985; Prada et al., 1991; Turk et al., 1992), viruses like parvo virus (Toma and Moraillon, 1980; Barrios et al., 1989; Mohan et al., 1993; Hoskins, 1997), endoparasites like Dipylidium caninum, Ancylostoma caninum (Ndiritu and Sadi, 1977; Kumar et al., 2001), ingestion of toxic herbicides, pesticides and fertilizers and irritant drugs (Paul and William, 1973; Cornelius and Wingfield, 1980).
       
Enteritis of hookworm origin in the dogs is of public health importance because of the danger of developing cutaneous larvae migrans in associated human population. Parasitism is the most encountered disease in dogs all over the world (Zelon, 2003) and dog can have internal parasites even though the fecal sample is negative. Gastrointestinal helminths of dogs pose serious impact both on the host and human beings.
       
Successful rearing of dogs is impeded by these parasites as they can lead to lower immunity and make the dogs prone to other infectious diseases, retarded growth, reduced work and feed efficiency and general ill health (Soulsby, 1982). Severe cases can lead eventually to death of the animals (Barutzki and Schaper, 2003). The present pathological and parasitological work elucidates the presence of parasitic fibrino-necrotic enteritis in a Rottweiler dog due to presence of Dipylidium caninum and Toxacara canis.

A carcass of Rottweiler breed male dog of around 7 years age was received in the post mortem hall of the Department of Veterinary Pathology, LUVAS, Hisar, Haryana (India) from Department of Veterinary Clinical Complex, LUVAS, Hisar in the month of September, 2017. After collection of the samples, laboratory work was undertaken in the laboratories of Department of Veterinary Pathology and Veterinary Parasitology, LUVAS, Hisar, Haryana (India) in the year 2018-2019.
 
Clinical history
 
Clinical history was recorded from the OPD farm which includes clinical signs, course of illness, treatment given etc. of the clinically affected dog.
 
Pathological studies
 
Thorough postmortem examination was conducted for examination of gross pathological lesions in different organs. All the organs and tissues of the dog were examined critically and the lesions observed were recorded. The parasitic worms observed the intestinal lumen were sent to the Department of Veterinary Parasitology for further detailed identification study. Representative and appropriate tissue samples from organs showing lesions like liver, lungs, heart, intestine, kidney and spleen were collected in 10% buffered formalin for histopathological studies. The formalin fixed tissues were processed for paraffin embedding technique. The section were cut at the thickness of 3-4 µ and stained with H & E stain (Luna, 1968).
 
Parasitological examination
 
The parasites received were washed with normal saline solution and preserved in 10% formalin for two days. Later the worms were washed under running tap water and stained (with H & E stain) for morphological characters and identification.

History revealed that the dog was suffering from illness since seven-eight days showing inappetance, pyrexia, diarrhoea and nasal discharge. External examination of the carcass revealed anaemic mucous membranes, pale conjunctiva of the eyes. Grossly, there was hydrothorax and hydroperitoneum, lungs and heart appeared congested. Intestinal lumen was empty and jejunum contained 4-5 cm long and 2-3 mm broad white nematodes (Fig 1) as well as 15 to 20 cm long creamy cestodes (Fig 2) with cucumber seed shaped segments, being broadest at middle. Mucosa of large intestine was found congested (Fig 3). Liver revealed areas of hypostatic congestion along with blackish discolouration (Fig 4). Gall bladder was fully distended. Intestine revealed congested and thickened mucous membrane. Kidneys were soft in consistency and urinary bladder was found distended.
 

 

 

 

       
Histopathologically, liver revealed presence of congestion, haemorrhage and telengiectiasis along with atrophy of hepatic chords, infiltration of mono nuclear cells and areas of necrotic hepatitis (Fig 5, 6). Lungs showed pneumonic lesions with red hepatization characterized by congested and hemorrhagic pulmonary blood vessels, infiltration of mononuclear cells in parenchyma, emphysematous alveolar changes and anthracosis (Fig 7). Heart showed mild degenerative changes of myocardial fibers only. Intestine revealed presence of severe fibrinous necrotic enteritis characterized by degeneration and desquamation of microvilli, congested mucosal and sub mucosal blood vessels along with haemorrhages and infiltration of mono nuclear cells (Fig 8). The necrotic areas of intestine contained fibrin mixed with cellular debris adherent to intestinal mucosa (Fig 9). Spleen revealed acute splenitis characterized by presence of severe hemorrhages along with necrosis of lymphocytes in white pulp and neutrophilic cell infiltration in parenchyma and haemosiderosis (Fig 10). Parasitological examination, the anterior portion of nematode revealed large cervical alae giving an arrow headed appearance. There were three lips on anterior side and oesophagus also had distinct posterior muscular ventriculus. The cestode had segments which were broader at the middle giving cucumber seed shaped appearance and had genital opening on both the sides. The stained gravid segment revealed many egg capsules each with 4-20 globular eggs all having hexacanth embryo. The studies confirms the recovered worms to be Toxacara canis (a nematode) and Dipylidium caninum (a cestode) indicating mixed parasitic disease condition.
 

 

 

 

 

 

      
Similar to our results, Dubey et al., (1998) reported T. canis ova in the faeces of a 10 month old German shepherd dog which was presented with an acute onset of lethargy, anorexia, vomiting and diarrhoea. In the present study infection with more than one helminthic parasite (polyparasitism) was found. Higher incidences of concurrent infections with more than one species of helminths (75.6%) were also reported by other researchers from Ethiopia (Reshid, 1988, Shimelis, 1994). Clinically the dog revealed anaemia, inappetance and diarrhea. Anaemia in parasitic conditions develops because parasites are totally dependent on host for food and thus they suck blood leading to chronic blood loss which leads to decrease in PCV and haemoglobin. Similarly, Sandhu et al., (1997) reported decline in the levels of haemoglobin and PCV as a result of A. caninum. Rao and Suryanarayana (1995) also reported decrease in the values of PCV and hemoglobin levels in toxocariasis in dogs. Kleinschmidt et al., (2006) carried out a survey on histological findings in full-thickness biopsies from the gastrointestinal tract (GIT) in 64 dogs showing symptoms of chronic diarrhoea. Out of 64 dogs, 2 dogs (3.12%) had fibrotic enteritis. Savilla (2009) reported the prevalence of parasitic infection in dogs from West Virginia and revealed that out of the 231 dogs surveyed, 23% had  Ancylostoma caninum, 8% had Trichuris vulpis and 7% had Toxocara canis infection. Similar to histopathological findings in our study, William et al., (1964) reported that extensive hemorrhagic necrosis of the bowel mucosa is a characteristic feature of dogs dying of parasitic shock. Grossly they revealed abnormally thickened mucosa like yellow brownish diphtheritic membrane, varying degrees of haemorrhages, ballooning of the intestine and expulsion of foul smelling gas after opening. Histopathologically they found severe necrosis of enteroepithelial cells with marked desquamation, increased cellular infiltration in lamina propria, fibrin mixed with cellular debris adherent to intestinal mucosa. Nho et al., (1997) reported cases of necrotic enteritis in 25 dogs and microscopically they found that in 3 of 25 dogs (dogs 23-25), ileal mucosa showed presence of mild epithelial cell necrosis accompanied by invasion of the lamina propria by moderate numbers of neutrophils and lymphocytes. Hayden and Kruiningen (1975) super infected eight dogs orally for 1 month with 50,000 embryonated T. canis ova and microscopically revealed the presence of focal eosinophilic gastroenteritis characterized by eosinophilic infiltration and granulomatous lesions. Lloyd et al., (1991) examined the tissue sections of small intestines from Beagle puppies infected with either a moderate or a low burden of T. canis and noticed a significant reduction in villous height that was inversely related to the extent of the infection. Villous goblet cell numbers, particularly those in the luminal third of the villus, were lowest and crypt goblet cell numbers were highest in heavily infected puppies. Savilla (2009) reported that mucosal layer was thickened and edematous and the adult Dipylidum worms were found attached to the mucosa of intestine. Microscopically, there was necrosis of the villi and marked infiltration of lymphocytes, plasma cells and few macrophages in the lamina propria. Eosinophilic homogenous necrotic areas and haemorrhages of variable size were also present in the submucosa. Traub et al., (2002) reported gastrointestinal parasitic prevalence in dogs in India and examined histopathologically a case of Dipylidium. Microscopically, adult worm were found adhering to mucosa and the mucosal surface was thickened due to infiltration of mononuclear cells and few plasma cells.

Present study concludes that in the mixed parasitic infestations like Toxocara canis and Dipylidium caninum severe fibrinous necrotic type enteritis is the main pathological conditions causing diarrhoea, malabsorption, dehydration and hypovolumic shock which if not treated in time may lead to death.

The authors are highly thankful to Dean, COVSc, LUVAS and Heads of the Department of Veterinary Pathology and Department of Veterinary Parasitology, COVSc., LUVAS, Hisar for providing the necessary facilities.