Clinico-therapeutic studies on canine microfilariasis
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Date
2009
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Department of Clinical Veterinary Medicine, College of Veterinary and Animal Sciences, Mannuthy
Abstract
etc. A study on canine microfilariosis was conducted in the Department of Clinical Veterinary Medicine, College of Veterinary and Animal Sciences, Mannuthy during the period of 2007-2009. Hundred dogs of both sexes belonging to various breeds and above 6 months of age presented to Veterinary College Hospital, Mannuthy and University Veterinary Hospital, Kokkala from different parts of Kerala with clinical signs suggestive of microfilariosis were screened for microfilaria by wet film examination. Wet film examination revealed that 80% of dogs were positive for microfilaria. Staining of blood smear with giemsa (1:10) demonstrated that 16 out of 80 dogs were positive for sheathed microfilaria and remaining were nonsheathed. Out of these 50 (nonsheathed) microfilaremic dogs were selected and treated at random with five schedules of treatment so that each schedule consisted of ten animals each (Group I, II, III, IV and V). Sheathed microfilaraemic animals were considered as a separate group for treatment trial. All these animals were subjected to periodic wet film examination on 2nd, 4th and 7th day of treatment to assess the treatment response.
High infestation rates were recorded in male dogs of 2-4 years of age than females irrespective of the type of microfilariae. High incidence of microfilariosis with non sheathed and sheathed microfilariae was observed in GSD and Labrador breeds respectively.
Diagnosis was made by parasitological studies, immunological and molecular techniques, clinical investigations and haematobiochemical analysis.
In wet film examination distinct patterns of motility was observed with the type of microfilariae present. The speciation of microfilariae were done based on morphological characteristics in giemsa stained smears, acid phosphatase enzyme activity, immunospot test and PCR analysis and sequencing of amplicon. The different species of microfilariae identified were that of Dirofilaria repens, Dipetalonema reconditum, Brugia malayi and Brugia pahangi. Of which Brugia malayi and Brugia pahangi were sheathed. Results of micrometry, staining, immunospot test and molecular studies revealed that the newly identified parasite were similar to that of Brugia malayi in human beings. This is the first report of detection of Brugia malayi in dogs for which no previous reports were available in pubmed or other literature data bases. Infact this is also the first report of Brugia pahangi in a dog from India and Dipetalonema reconditum from dogs of Kerala.
Detailed clinical investigations included ECG, ultrasonography and radiography were conducted to visualize the abnormalities encountered with vital organs.
Haematobiochemical studies of dogs affected with both non sheathed and sheathed microfilariae revealed mild anaemia with severe leucocytosis, neutropenia, lymphocytosis, eosinophilia, elevated ESR and severe thrombocytopaenia, hyperproteinemia with hyperglobulinaemia and non significant reduction in AG ratio, increased serum ALT, AST, ALP , BUN and creatinine values could be observed when compared to healthy controls. Qualitative urinalysis revealed proteinuria with reduced specific gravity. Quantitative analysis of urinary markers revealed elevation of NAG, UPC, γGT and ALP in microfilaraemic dogs.
The elevated levels of serum total protein, globulin, serum enzymes like ALT and ALP and nonsignificant reduction in AG ratio suggestive of liver pathology in microfilaraemic dogs. Elevated levels of BUN, creatinine, urine protein creatinine ratio, NAG, ALP, proteinuria with low specific gravity confirmed the renal involvement in microfilaraemic dogs irrespective of the type of microfilaria involved in the disease process. This multiorgan pathology in canine microfilariosis suggested the involvement of toxic and immunological effects of these parasite in the pathogenesis of the disease.
The treatment response was evaluated by the periodic clearance of microfilariae on wet blood film examination, remission of clinical signs and the improvement in haematobiochemical alterations. Single oral dose of ivermectin @ 100 µg/kg body weight can be selected as a treatment modality for microfilariosis due to Dirofilaria repens and Dipetalonema reconditum in dogs. Levamisole hydrochloride @ 10 mg/kg body weight for seven days was the only effective treatment for microfilariosis due to Brugia malayi in dogs. Result of post treatment values of hepatic and renal function test revealed that many of the parameters like ALT, ALP and BUN were still in elevated level.
Two animals died during the course of treatment were subjected to post mortem examination. The gross and hispathological examination revealed lesions in heart, lungs, liver and kidneys in microfilaraemic dogs. Myofibrillar fragmentation, atlectasis, thromboemboli formation, portal hepatitis and chronic interstitial nephritis were the major lesions observed.
Based on above studies it concluded that follow-up evaluation of these parameters could be a relevant approach to find out the therapeutic effectiveness. A therapeutic plan should consists of both specific and clinically supportive treatments to improve hepatic and renal function.
A study on canine microfilariosis was conducted in the Department of Clinical Veterinary Medicine, College of Veterinary and Animal Sciences, Mannuthy during the period of 2007-2009. Hundred dogs of both sexes belonging to various breeds and above 6 months of age presented to Veterinary College Hospital, Mannuthy and University Veterinary Hospital, Kokkala from different parts of Kerala with clinical signs suggestive of microfilariosis were screened for microfilaria by wet film examination. Wet film examination revealed that 80% of dogs were positive for microfilaria. Staining of blood smear with giemsa (1:10) demonstrated that 16 out of 80 dogs were positive for sheathed microfilaria and remaining were nonsheathed. Out of these 50 (nonsheathed) microfilaremic dogs were selected and treated at random with five schedules of treatment so that each schedule consisted of ten animals each (Group I, II, III, IV and V). Sheathed microfilaraemic animals were considered as a separate group for treatment trial. All these animals were subjected to periodic wet film examination on 2nd, 4th and 7th day of treatment to assess the treatment response.
High infestation rates were recorded in male dogs of 2-4 years of age than females irrespective of the type of microfilariae. High incidence of microfilariosis with non sheathed and sheathed microfilariae was observed in GSD and Labrador breeds respectively.
Diagnosis was made by parasitological studies, immunological and molecular techniques, clinical investigations and haematobiochemical analysis.
In wet film examination distinct patterns of motility was observed with the type of microfilariae present. The speciation of microfilariae were done based on morphological characteristics in giemsa stained smears, acid phosphatase enzyme activity, immunospot test and PCR analysis and sequencing of amplicon. The different species of microfilariae identified were that of Dirofilaria repens, Dipetalonema reconditum, Brugia malayi and Brugia pahangi. Of which Brugia malayi and Brugia pahangi were sheathed. Results of micrometry, staining, immunospot test and molecular studies revealed that the newly identified parasite were similar to that of Brugia malayi in human beings. This is the first report of detection of Brugia malayi in dogs for which no previous reports were available in pubmed or other literature data bases. Infact this is also the first report of Brugia pahangi in a dog from India and Dipetalonema reconditum from dogs of Kerala.
Detailed clinical investigations included ECG, ultrasonography and radiography were conducted to visualize the abnormalities encountered with vital organs.
Haematobiochemical studies of dogs affected with both non sheathed and sheathed microfilariae revealed mild anaemia with severe leucocytosis, neutropenia, lymphocytosis, eosinophilia, elevated ESR and severe thrombocytopaenia, hyperproteinemia with hyperglobulinaemia and non significant reduction in AG ratio, increased serum ALT, AST, ALP , BUN and creatinine values could be observed when compared to healthy controls. Qualitative urinalysis revealed proteinuria with reduced specific gravity. Quantitative analysis of urinary markers revealed elevation of NAG, UPC, γGT and ALP in microfilaraemic dogs.
The elevated levels of serum total protein, globulin, serum enzymes like ALT and ALP and nonsignificant reduction in AG ratio suggestive of liver pathology in microfilaraemic dogs. Elevated levels of BUN, creatinine, urine protein creatinine ratio, NAG, ALP, proteinuria with low specific gravity confirmed the renal involvement in microfilaraemic dogs irrespective of the type of microfilaria involved in the disease process. This multiorgan pathology in canine microfilariosis suggested the involvement of toxic and immunological effects of these parasite in the pathogenesis of the disease.
The treatment response was evaluated by the periodic clearance of microfilariae on wet blood film examination, remission of clinical signs and the improvement in haematobiochemical alterations. Single oral dose of ivermectin @ 100 µg/kg body weight can be selected as a treatment modality for microfilariosis due to Dirofilaria repens and Dipetalonema reconditum in dogs. Levamisole hydrochloride @ 10 mg/kg body weight for seven days was the only effective treatment for microfilariosis due to Brugia malayi in dogs. Result of post treatment values of hepatic and renal function test revealed that many of the parameters like ALT, ALP and BUN were still in elevated level.
Two animals died during the course of treatment were subjected to post mortem examination. The gross and hispathological examination revealed lesions in heart, lungs, liver and kidneys in microfilaraemic dogs. Myofibrillar fragmentation, atlectasis, thromboemboli formation, portal hepatitis and chronic interstitial nephritis were the major lesions observed.
Based on above studies it concluded that follow-up evaluation of these parameters could be a relevant approach to find out the therapeutic effectiveness. A therapeutic plan should consists of both specific and clinically supportive treatments to improve hepatic and renal function.
Further studies are warranted to elucidate the possible role of dogs in the transmission of human filariasis and to develop a suitable therapeutic approach to treat canine microfilariosis in the increasing ewe of chronic renal diseases in dogs.
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