Browsing by Author "Subramanian, H"

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Effect of certain biopesticides and irradiation on the developmental stages of myiasis producing flies
(Department of Parasitology, College of Veterinary and Animal Sciences,Mannuthy, 1998) Subramanian, H; Rajamohanan, K
A study was undertaken on the prevalence of cutaneous myiasis in domestic animals and its control using bio-pesticides and gamma irradiation. The prevalence of cutaneous myiasis in domestic animals was found to be 205 (2.08 per cent) among .the 9861 animals screened. The peak of infestation was noted in the month of January. In host-wise and parasite-wise the highest incidence was noted in cattle (63.41 per cent) and the majority of infestation was produced by Chrysomya bezziana larvae (90.73 per cent). Methoprene at 1 to 50 ppm concentration caused only moderate mortality on larvae but significantly increased the mortality rate on eggs, prolonged the larval phase, increased the formation of larval pupal intermediaries and adult deformities and reduced the adult emergence. Diflubenzuron at 0.5 to 5 ppm caused 55 to 100 per cent larvicidal effect due to lowered chitin content of 18.42 to 52.11 per cent in larval cuticle. Bacillus thuringiensis var israelensis produced only moderate larval mortality at 160 to 800 ppm in myiasis producing flies. Azadirachtin at 10.5 to 15 ppm produced 100 per cent mortality in eggs and larvae. Significant antifeedant, ovipositional deterrent and repellant effects were also produced by Azadirachtin. Among the extracts of Acarus calamus, studied, petroleum ether extract at 2.5 per cent concentration gave 82.5 to 100 per cent mortality of the larvae. Moderate antifeedant, ovipositional deterrent and repellant effects were also noticed. The petroleum ether extract produced 100 per cent sterility at 0.1 to 1 per cent concentration by preventing the development of ovarian follicles. Three day old pupae of myiasis producing flies exposed to r-rays gave excellent sterility effect at 2000 to 4000 rads radiation exposure without any other deleterious effect in the flies. Diflubenzuron at 5 ppm concentration showed the highest larvicidal effect (88.5 per cent) in natural cases of cutaneous myiasis.
Effect of certain newer generation insecticides on the developmental stages of mosquitoes
(Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Mannuthy, 2005) Lucy Sabu; Subramanian, H
Mosquitoes collected from five cattle sheds and human dwellings in and around Thrissur were identified into 27 species coming under seven genera in three subfamilies. Only one genus each could be found in the subfamilies of Toxorhynchitinae and Anophelinae, while there were five genera in the subfamily Culicinae. The genus Culex constituted 67.1 per cent of the total collection. Culex tritaeniorhynchus was identified as the most prevalent species in cattle sheds while in human dwellings it was Cx. quinquefasciatus. Culex tritaeniorhynchus was successfully colonized in the laboratory. The development of adults from eggs took 7-18 days under laboratory conditions. The average number of eggs laid by a female was 42. The average survival time was 45 days. The male mosquitoes always emerged first from the pupae. Dissection of 1001 mosquitoes collected from cattle sheds did not reveal any helminth larvae. Meanwhile, 1019 mosquitoes collected from human dwellings in the vicinity of dog houses when dissected revealed helminth larvae in two mosquitoes. The larvae were identified as those of Dirofilaria repens based on morphology. Six different insecticides namely, diflubenzuron, methoprene, Bti, azadirachtin, ethofenprox and deltamethrin were evaluated for their effect on the eggs, 4th stage larvae and pupae of Cx. tritaeniorhynchus. The 4th stage larvae were more susceptible to all the insecticides with the least concentration of LC50 and LC90. The IGRs used in the study were most efficient. In terms of LC50 concentration on larvae, the various insecticides in the order of efficacy were diflubenzuron (0.0002288 ppm), methoprene (0.0006738), deltamethrin (0.0020853) ethofenprox (0.0082146), azadirachtin (4.6867982) and Bti (6.6076021). The IGRs -diflubenzuron and methoprene- are recommended for use in mosquito larval control as only minimum concentration need to be used. Methoprene had no effect on the eggs whereas several multiples of the other insecticides were needed to produce the same effect on eggs or pupae. In case of azadirachtin, the LC50 on larvae and pupae were almost same. When MRP alone was considered, ethofenprox was found to be the cheapest insecticide, costing Rs.0.03/- per one lakh litres of water followed by deltamethrin (Rs. 0.51/-). The most expensive one was Bti (Rs. 2179/-) followed by azadirachtin (Rs. 1630/-). Among the IGRs diflubenzuron was much cheaper (Rs. 1.38/-) than methoprene (Rs. 13.87). To avoid selection pressure on immature stages of mosquitoes, deltamethrin and ethofenprox should not be used for larval mosquito control as they are invaluable adulticides.
Immunodiagnosis of canine dirofilariosis using microfilarial antigen
(Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Mannuthy, 2003) Priya, M N; Subramanian, H
A detailed study was conducted on the prevalence on canine dirofilariosis in Thrissur from June 2002 to May 2003, feasibility of microfilarial antibody detection by ELISA and comparison of sensitivity of Indirect ELISA and dot- ELISA in the detection of dirofilariosis. Microfilariae encountered were identified as those of Dirofilaria repens. Out of the total number of2435 blood samples from dogs screened by wet film examination 172 (7.06 per cent) dogs were found positive for microfilariae. It has been found that canine dirofilariosis was prevalent throughout the year with more incidence during summer. An Indirect ELISA and dot-ELISA were also conducted in three groups of animals using microfilarial antigen prepared from known microfilaria positive serum samples. Out of the total number of 50 samples of known microfilaria positive dogs 49 (98 per cent) and 47 (94 per cent) were found positive by Indirect ELISA and dot-ELISA respectively. The corresponding figures in 36 dogs with other helminths were 15 (41.67 per cent) and 19 (52.77 per cent) and that of32 totally helminth free dogs were 10 (31.25 per cent) and 12 (37.5 per cent) respectively. The results indicate that both Indirect ELISA and dot-ELISA are feasible for the detection of the microfilarial antibodies though they are less specific.
Immunoprophylaxis against common dog tick using gut antigen
(Department of Veterinary Parasitology,College of Veterinary and Animal Science,Mannuthy, 2005) Ajithkumar, K G; Subramanian, H
The occurrence of tick infestation in dogs in the Corporation of Thrissur, Kerala, India, was studied in 1200 dogs during a period of one year from July 2004 to June 2005. Four hard tick species viz Rhipicephalus sanguineus, R. haemaphysaloides, Haemaphysalis bispinosa, H. bispinosa var. intermedia were identified. Significant difference in species wise prevalence was found on 124 tick positive dogs. The most prevalent species of tick infesting dogs was found to be R. sanguineus (8.58 per cent) followed by H. bispinosa (1.33 per cent), R. haemaphysaloides (0.33 per cent) and H. bispinosa var. intermedia (0.08 per cent). Three species of ticks namely R. haemaphysaloides, H. bispinosa, and H. bispinosa var. intermedia have been recorded in dogs for the first time from Kerala. The influence of month, season, age, gender and breed on the prevalence rate were observed. Prevalence rates were calculated by month, season, age, gender and breed. No significant difference (P>0.05) of tick infestation during different months was observed due to temperature, relative humidity, and rainfall. No clear pattern of seasonality was observed for R. sanguineus, which was present throughout the year. The different variables considered in the present study such as age and gender were not significantly associated with the presence of tick infestation in dogs. There was a highly significant (P<0.01) association between breed and the intensity of infestation with maximum intensity of infestation in German shepherd dogs. Sites of attachment of ticks were ear, neck, interdigital space, dorsum of the body, eyelids, perianal region, withers, thorax and hind limbs. Highly significant variation (P<0.01) was observed between attachment sites with maximum on ear (84.68 per cent) followed by neck and interdigital space. Tick-bite naive guinea pigs inoculated with gut extracts and Freund’s adjuvant revealed induced immunity against R. sanguineus expressed by altered feeding and fertility parameters consisting of the prolonged engorgement period, reduced engorged female weight and feeding efficiency index, prolonged pre oviposition period, reduced oviposition period, egg mass weight, egg rate conversion efficiency and larval mass. Except the incubation period all the reproductive and feeding parameters differed significantly compared to the control. Inradermal test done on immunised guinea pigs to assess cell mediated immunity revealed both immediate and delayed hypersensitivity reaction. Humoral immune response assessed by agar gel immunodiffusion (AGID) and passive haemagglutination (PHA) revealed that the former was less sensitive compared to the latter. Passive haemagglutination test detected anti tick antibodies as early as 14th day post immunisation. Peak titre 1:128 reached on the 35th day post immunisation.
Prevalence clinical pathology and treatment of microfilariasis in dogs in Thrissur
(Department of Parasitology, College of Veterinary and Animal Sciences, Mannuthy, 1997) Radhika, R; Subramanian, H
Prevalence, Immune response and control of Stomoxys spp. of flies
(Department of Veterinary Parasitology, College of Veterinary and Animal Science, Mannuthy, 2000) Basker, N; Subramanian, H
A detailed study on the prevalence, biology, immune response and control of Stomoxys spp. of flies was conducted. The prevalence study on Stomoxys fly infestation on cattle of Thrissur, during June 1999 to May 2000 showed a higher incidence (>90 per cent) during the months of June, July, August and September than in other months. The prevalence increased as temperature decreased and humidity and rainfall increased. The fly infesting cattle was identified. as Stomoxys calcitrans. The biology of the fly was studied in laboratory and were fed with citrated bovine blood. The use of horse dung as oviposition and larval development medium was found to be satisfactory. The life cycle parameters of the fly were also noted. The thoracic muscle antigen prepared from pharate adult fly was used for immunization. Agar gel precipitation test and counter immuno electrophoresis revealed a single clear precipitation line. The passive haemagglutination assay revealed an antibody titre of 1024, on days 21 st and 28th of immunization. Feeding the normal flies with blood from immunized rabbit produced a cumulative mortality of 100 per cent on day 20 against 66.7 per cent mortality in flies fed with control rabbit blood. Abnormal effects like wing paralysis was noted in test group. The insecticidal property of Deltamethrin, Diazinon, Carbaryl and Ethofenprox were evaluated against stable fly infestation and was found that Deltamethrin (0.0025 per cent) was highly effective in controlling flies. At 0.005 per cent concentration Deltamethrin gave better protection. Diazinon (0.3 per cent) and Carbaryl (0.1 per cent) failed to provide good protection after one day post treatment. Ethofenprox (0.002 per cent) was found to be least effective.
Prevalence, immune response and treatment of mite infestation in rabbits
(Department of Parasitology, College of Veterinary and Animal Sciences, Mannuthy, 1998) Regu Ravindran; Subramanian, H
Studies on the flies producing cutaneous myiasis in domestic animals in Trichur
(Department of Parasitology, College of Veterinary and Animal Sciences, 1978) Subramanian, H; Raja Mohanan, K
A detailed study on the incidence of cutaneous myiasis among domestic animals in Trichur, the morphology and biology of the causative flies and the efficacy of indigenous oils and chemicals as repellents against these flies were undertaken. Cutaneous myiasis was found common among domestic animals in Trichur during the months of October to May, the maximum number being, during January to March. The cases were observed in cattle, buffaloes, goats and dogs. The most common causative fly was Chrysomyia bezziana, but other flies such as Chrysomyia megacephala, Chrysomyia rufifacies and Lucilia cuprina were also observed. In cattle and buffaloes, the lesions were noted mostly in vulval lips and nasal septa where as in goats and dogs the cases were observed on the body skin. The flies of Chrysomyia megacephala, Chrysomyia rufifacies, Chrysomyia nigripes, Lucilia cuprina and Sarcophaga ruficornis were reared in the laboratory to study their morphology and biology. The larvae of Lucilia cuprina and Sarcophaga ruficornis were smooth. Chrysomyia bezziana, Chrysomyia megacephala and Chrysomyia nigripes were spiny and Chrysomyia rufifacies hairy. Chrysomyia rufifacies had the shortest life cycle period of 16 days and Sarcophaga ruficornis had the longest of 26 days. Lucilia cuprina could be reared in the laboratory for 71 days. The invitro development of the larvae, the development of the pupae and the process of fly emergence of Chrysomyia megacephala and Sarcophaga ruficornis were studied in detail. Among the fly repellents tested, lemongrass oil proved to be the best one in possessing fly repellent potentially followed by camphor in oil and Eucalyptus oil against blowflies and Sarcophaga species. Kerosine oil and Turpentine oil possessed the maximum larvicidal action on the larvae of Chrysomyia megacephala and Sarcophaga ruficornis. Turpentine oil and pine oil possessed excellent ovicidal action on Lucilia cuprina eggs even on smearing.