The first case of schistosomiasis was reported from a boy by Hatch in 1878 from India. Since then many cases of human schistosomiasis were reported from different parts of the country but raising controversies mainly because of absence of related snail species. Not withstanding this fact, an endemic focus of human schistosomiasis was identified in Gimvi village of Ratnagiri district where a new snail species ( Ferrissia tenuis) was claimed as its new intermediate host. This raised many questions , most of them remained unanswered. Further , eggs of a native blood –fluke species (Schistosoma incognitum) were detected in two human stools suggesting it as new human schistosomes species. When its adults were recovered frm pigs, the original finding came under controversy. Thus India or for that matter whole South Asia is a fascinating place which has many answers for the global problem of schistosomiasis. Nevertheless, Indian scientists are working on schistosomiasis in isolation since international organizations have completely neglected the whole geographical area.
Jabalpur, within Madhya Pradesh, India, is the place where fossils of Dinouser’s eggs have been recovered. This is the place where atleast six mammalian schistosome species ( Schistosoma spindale,S.indicum, S.nasale, S.incognitum,Orientobilharzia dattai, Bivitellobilharzia nairi) do occur in animals.India is the place from where six schistosome species ( S.indicum,S.incognitum,S.spindale,S.nasale,O.dattai, B.nairi ) have originated.
There are many questions to be solved by the scientific community. What is the interplay between these species in intermediate and final hosts? Why Indian schistosomes are poor egg producers? What are the chances of cross-fertilization and formation of new hybrids ?Why Indian schistosomes are responding differently to well known schistosomicides ? Is there any co-relation between infertility or low milk production in bovines to latent schistosome infections ? How many schistosomes species have remained unidentified ? Why Indian schistosomes have not evolved through river routes ? How the fluke behaves in immunologically compromised man ? What is the fate of schistosome species in human cases of cercarial dermatitis ?
We consider African schistosomes as the predecessors of all the schistosomes including those of India . But Indian schistosomes are apparently well tolerated or well adapted to their final hosts causing comparatively less injury. Who has, then, originated first ?
I ,as Indian Veterinary Parasitologist has devoted my whole academic life to understand schistosomes and schistosomiasis in India. In my latest work as Emeritus Scientist,ICAR , we conclusively proved efficacy of triclabendazole in treating schistosomiasis including nasal schistosomiasis.I am still interested to spread knowledge on schistosomiasis to other countries and willing to participate in any such program. Any interested institute/organization/scientist may contact me.
Thursday, May 22, 2008
SCHISTOSOMES AND SCHISTOSOMIASIS IN INDIA:
Work has been initiated on schistosomes and schistosomiasis in India by imminent Parasitologists like Montgomery, Chandler, Rao, Soparker, Gadgil, Srivastava, Anantaraman, Alwar, Dutt etc. Indeed, Schistosoma indicum, S.spindale, S.incognitum, S.nasale, Orientobilharzia.dattai were discovered and christened in India only. There have been several I.C.A.R., I.C.M.R. research projects, presidential addresses in different scientific congresses on Schistosomes and schistosomiasis. Despite these efforts, there is much to be done to understand schistosomiasis in India and other south Asian countries because of its many peculiarities.There is also need to compare the biology of Indian schistosomes with other schistosomes as such studies will enhance our knowledge on the blood fluke. We may provide consultancy on this subject.
Infection and Recovery of Blood Flukes. There is a great difficulty of infecting animals with schistosome cercariae as their normal rout of infection is percutaneous. The previous workers either used per os method resulting inconsistent recoveries or very tedious methods with doubtful efficacy.
The percutaneous method of infecting guinea pigs and rabbits with schistosome cercariae requires proper restraining of the animals and may lead to loss of the cercariae if proper control is not maintained. This difficulty is solved by putting the schistosome cercariae in a polythene bag and fastening the same either in the paw or tail . Later it is used in goats using ear-pinnah of the animal hence now the simple method may be used in any size of the animal.
Earlier, schistosomes were recovered in India by chopping the organs in saline and searching the flukes afterwards .This is not an accurate method of blood-fluke recovery hence we modified and adapted a perfusion technique which is quite effective in recovering the flukes from experimental animals This technique is followed later by other Indian workers .
The perfusion technique is further been improved by replacing automatic pippeting machine with a vertical water pump (tullu Vijay) commonly used in the desert coolers . This has not only reduced cost of the equipment from Rs 40,000/ to only Rs 600/ (Rs Six hundred only) but enabled perfusion of different sized animals effectively. Now with this technique , any size of the animal may be perfused for recovery of the blood flukes.
Maintetance of Fresh Water Snails. The fresh water snails ( Indoplanorbis exustus and Lymnaea luteola ) were maintained and bred in small numbers in the laboratory by keeping them in earthen pots, glass jars etc ,and changing water daily. This caused heavy mortality of the snails making the whole work tiresome, and non workable. Moreover, there was no effective way to follow up individual snail for any biological activity.
A new method of keeping fresh water snails (Lymnaea luteola and Indoplanorbis exustus )in the polythene bags with addition of mulberry leaves and stored water at the rate of 50 ml/snail is developed which facilitates easy transport of the snails ,individual snail observation, no need of daily change of water and reduced mortality .
In another technique ,a cement tank of 8 feet diameter and 14 inch depth was constructed with an water inlet in the center and filled with mud ,water ,aquatic weeds including lotus and wild snails. The tank was able to sustain life of both the snails with their breeding .The method was used to infect L.luteola with positive pig faeces and recovering Schistosoma incognitum cercariae in large number after about 30 days .Our method is of great assistance for survey work and to search snail hosts for specific trematodes.
Egg and Granuloma Count. When work on schistosome immunity was initiated in India, fluke recovery and their size were the only criteria used for judging immune response. Two additional criteria viz. egg and granuloma count were added by us.For this , a very simple technique is developed . The egg and granuloma count not only judged effectively the immune response but also assessed tissue damage of the host. These methods may also be used for assessing effect of the drug on schistosomiasis.
Patent Schistosome Infection in Mouse. Though albino mouse is a good host for development of Schistosoma incognitum . However ,our predecessors (Sinha & Srivastava, 1965, Ahluwalia, 1972, Nikhale, 1972) failed to demonstrate S.incognitum eggs in mouse faeces and have postulated a hypothesis for the same. Fresh attempts were made by us by examining mice faeces but by acid-ether and hatching method. We proved that mice do pass S.incognitum eggs in their faeces Thus S.incognitum - mouse model became an ideal one for chemotherapeutic and immunological studies.
Zoonotic Potentials. Though animal schistosomiasis is a well documented entity in India and South Asia, there is a controversy over existence of human schistosomiasis in these countries.. It’s a general view that human schistosomiasis was reported only from Gimvi village of Ratnagiri district ;now it is non-existing in India. This view is far from the truth. It may be recalled that eggs of S.incognitum were first detected in two human stools suggesting possibility of human schistosomiasis in Indian peninsula by a native blood-fluke. We have substantiated the possibility of human sufferings by experimentally infecting rhesus monkeys with S.incognitum and studying liver damage histochemically, histopathologically and biochemically by immature blood flukes. Therefore, man can not escape the pathology even if he develops the fluke only upto a particular stage. Large number of mammalian and avian schistosomes are existing for which man has graded susceptibilities. Moreover, Cercarial dermatitis is wide spread in rural India and no work has been undertaken to follow up these cases- at what stage the schistosomula die or under what conditions it may grow further . Recently, urine of the persons, with the history of cercarial dermatitis was tested for circulating antigens by employing a single step test kit ,developed in Netherland .Out of 30 cases tested, four turned positive suggesting excretion of schistosome antigens in the urine Therefore, it is a complacent view to consider absence of human schistosomiasis from Indian continent.
Diagnosis of Schistosomiasis. We have compared various parasitological diagnostic methods vis a vis serological methods (CHR, COP, MIT, IHA, RPT, ELISA ) and highlighted ineffectiveness of former methods in assessing schistosomiasis in our animals. By faecal egg detection methods , the prevalence of bovine schistosomiasis worked out to be 5-10%, by hatching to 20% and by serological methods it proved to be 80-90% .The coprological method of examining animals for parasitic infections has further been simplified by using LDPE polythene bags in place of microslide and cover slip which has not only reduced the cost of faecal examination but enabled to dispatch the specimen at any place for seeking experts opinion .Serological tests like MIT, CHR & ring precipitation were 80-90% sensitive and specific in diagnosing schistosomiasis. However, use of J-index showed change in sensitivity and specificity of serological tests as per efficacy of the parasitological test employed as reference test .Mesentery examination is effective in detecting schistosomiasis (raising infection to 80-90% in bovines, 48% in goats ) . Nevertheless, intestinal scraping proved more simple and effective, in comparison to mesentery examination but by employing large intestine. We have developed Dot-ELISA method for diagnosing schistosomiasis that may be employed under field conditions .
Chemotherapy. Lithium antimony thiomalate (Anthiomaline) is the most common drug being used in the field for treating nasal schistosomiasis albeit relapses of the cases within 1-3 month of the treatment. Our experimental work in guinea pigs, infected with S.spindale revealed the ability of anthiomaline to kill the blood flukes only at the level of 10-39% even with a higher dose .Praziquantel , a more costly drug, could cause only shift of S.incognitum flukes to the lungs of rats without killing them significantly . Among refoxanide, CDRI 81/470, oxyclozanide, closantel, triclabendazole, the last drug was comparatively more effective in killing S.incognitum in mouse model but none could cause a significant blood fluke reduction . We tested triclabendazole, praziquantel, rafoxanide and anthiomaline in clinical cases of nasal schistosomiasis at Balaghat district of M P. There was no effect of rafoxanide while anthiomaline caused recovery but with relapses of the symptoms. In contrast, triclabendazole and praziquantel were able to cure the cases clinically. There is a need to explore triclabendazole as a chemotherapeutic agent for schistosomiasis as it is also used against fascioliasis in cattle but with lower doses..
Nasal Schistosomiasis. Nasal schistosomiasis or snoring disease was considered to be absent from Jabalpur since local cattle did not exhibit symptoms of the disease. Our epizootiological studies supported this view as neither symptoms nor eggs of the fluke could be observed in the local cattle. Nonetheless, the parasite was shown to exist in Jabalpur in native buffaloes and cross-bred cattle with the clinical signs in later cases The epizootiology of nasal schistosomiasis is different from that of hepatic schistosomiasis.
Though there have been lot of research papers, presidential addresses, few review articles and chapters on South Asian schistosomes and schistosomiasis since last hundred years , yet there was no book which could deal the subject in a comprehensive way.To fill up this gap, I have written book "Schistosomes and schistosomiasis in South Asia" which has been published in Springers India Pvt Ltd in June ,2012 and may be viewed by any one on the website www.springer.com The book comprises 12 chapters and even single chapter may be taken from the publisher.
I will be glad to correspond with any person/trust/organization who is interested to control schistosomiasis and other parasitological infections in our animals including dealing with zoonotic diseases.
Infection and Recovery of Blood Flukes. There is a great difficulty of infecting animals with schistosome cercariae as their normal rout of infection is percutaneous. The previous workers either used per os method resulting inconsistent recoveries or very tedious methods with doubtful efficacy.
The percutaneous method of infecting guinea pigs and rabbits with schistosome cercariae requires proper restraining of the animals and may lead to loss of the cercariae if proper control is not maintained. This difficulty is solved by putting the schistosome cercariae in a polythene bag and fastening the same either in the paw or tail . Later it is used in goats using ear-pinnah of the animal hence now the simple method may be used in any size of the animal.
Earlier, schistosomes were recovered in India by chopping the organs in saline and searching the flukes afterwards .This is not an accurate method of blood-fluke recovery hence we modified and adapted a perfusion technique which is quite effective in recovering the flukes from experimental animals This technique is followed later by other Indian workers .
The perfusion technique is further been improved by replacing automatic pippeting machine with a vertical water pump (tullu Vijay) commonly used in the desert coolers . This has not only reduced cost of the equipment from Rs 40,000/ to only Rs 600/ (Rs Six hundred only) but enabled perfusion of different sized animals effectively. Now with this technique , any size of the animal may be perfused for recovery of the blood flukes.
Maintetance of Fresh Water Snails. The fresh water snails ( Indoplanorbis exustus and Lymnaea luteola ) were maintained and bred in small numbers in the laboratory by keeping them in earthen pots, glass jars etc ,and changing water daily. This caused heavy mortality of the snails making the whole work tiresome, and non workable. Moreover, there was no effective way to follow up individual snail for any biological activity.
A new method of keeping fresh water snails (Lymnaea luteola and Indoplanorbis exustus )in the polythene bags with addition of mulberry leaves and stored water at the rate of 50 ml/snail is developed which facilitates easy transport of the snails ,individual snail observation, no need of daily change of water and reduced mortality .
In another technique ,a cement tank of 8 feet diameter and 14 inch depth was constructed with an water inlet in the center and filled with mud ,water ,aquatic weeds including lotus and wild snails. The tank was able to sustain life of both the snails with their breeding .The method was used to infect L.luteola with positive pig faeces and recovering Schistosoma incognitum cercariae in large number after about 30 days .Our method is of great assistance for survey work and to search snail hosts for specific trematodes.
Egg and Granuloma Count. When work on schistosome immunity was initiated in India, fluke recovery and their size were the only criteria used for judging immune response. Two additional criteria viz. egg and granuloma count were added by us.For this , a very simple technique is developed . The egg and granuloma count not only judged effectively the immune response but also assessed tissue damage of the host. These methods may also be used for assessing effect of the drug on schistosomiasis.
Patent Schistosome Infection in Mouse. Though albino mouse is a good host for development of Schistosoma incognitum . However ,our predecessors (Sinha & Srivastava, 1965, Ahluwalia, 1972, Nikhale, 1972) failed to demonstrate S.incognitum eggs in mouse faeces and have postulated a hypothesis for the same. Fresh attempts were made by us by examining mice faeces but by acid-ether and hatching method. We proved that mice do pass S.incognitum eggs in their faeces Thus S.incognitum - mouse model became an ideal one for chemotherapeutic and immunological studies.
Zoonotic Potentials. Though animal schistosomiasis is a well documented entity in India and South Asia, there is a controversy over existence of human schistosomiasis in these countries.. It’s a general view that human schistosomiasis was reported only from Gimvi village of Ratnagiri district ;now it is non-existing in India. This view is far from the truth. It may be recalled that eggs of S.incognitum were first detected in two human stools suggesting possibility of human schistosomiasis in Indian peninsula by a native blood-fluke. We have substantiated the possibility of human sufferings by experimentally infecting rhesus monkeys with S.incognitum and studying liver damage histochemically, histopathologically and biochemically by immature blood flukes. Therefore, man can not escape the pathology even if he develops the fluke only upto a particular stage. Large number of mammalian and avian schistosomes are existing for which man has graded susceptibilities. Moreover, Cercarial dermatitis is wide spread in rural India and no work has been undertaken to follow up these cases- at what stage the schistosomula die or under what conditions it may grow further . Recently, urine of the persons, with the history of cercarial dermatitis was tested for circulating antigens by employing a single step test kit ,developed in Netherland .Out of 30 cases tested, four turned positive suggesting excretion of schistosome antigens in the urine Therefore, it is a complacent view to consider absence of human schistosomiasis from Indian continent.
Diagnosis of Schistosomiasis. We have compared various parasitological diagnostic methods vis a vis serological methods (CHR, COP, MIT, IHA, RPT, ELISA ) and highlighted ineffectiveness of former methods in assessing schistosomiasis in our animals. By faecal egg detection methods , the prevalence of bovine schistosomiasis worked out to be 5-10%, by hatching to 20% and by serological methods it proved to be 80-90% .The coprological method of examining animals for parasitic infections has further been simplified by using LDPE polythene bags in place of microslide and cover slip which has not only reduced the cost of faecal examination but enabled to dispatch the specimen at any place for seeking experts opinion .Serological tests like MIT, CHR & ring precipitation were 80-90% sensitive and specific in diagnosing schistosomiasis. However, use of J-index showed change in sensitivity and specificity of serological tests as per efficacy of the parasitological test employed as reference test .Mesentery examination is effective in detecting schistosomiasis (raising infection to 80-90% in bovines, 48% in goats ) . Nevertheless, intestinal scraping proved more simple and effective, in comparison to mesentery examination but by employing large intestine. We have developed Dot-ELISA method for diagnosing schistosomiasis that may be employed under field conditions .
Chemotherapy. Lithium antimony thiomalate (Anthiomaline) is the most common drug being used in the field for treating nasal schistosomiasis albeit relapses of the cases within 1-3 month of the treatment. Our experimental work in guinea pigs, infected with S.spindale revealed the ability of anthiomaline to kill the blood flukes only at the level of 10-39% even with a higher dose .Praziquantel , a more costly drug, could cause only shift of S.incognitum flukes to the lungs of rats without killing them significantly . Among refoxanide, CDRI 81/470, oxyclozanide, closantel, triclabendazole, the last drug was comparatively more effective in killing S.incognitum in mouse model but none could cause a significant blood fluke reduction . We tested triclabendazole, praziquantel, rafoxanide and anthiomaline in clinical cases of nasal schistosomiasis at Balaghat district of M P. There was no effect of rafoxanide while anthiomaline caused recovery but with relapses of the symptoms. In contrast, triclabendazole and praziquantel were able to cure the cases clinically. There is a need to explore triclabendazole as a chemotherapeutic agent for schistosomiasis as it is also used against fascioliasis in cattle but with lower doses..
Nasal Schistosomiasis. Nasal schistosomiasis or snoring disease was considered to be absent from Jabalpur since local cattle did not exhibit symptoms of the disease. Our epizootiological studies supported this view as neither symptoms nor eggs of the fluke could be observed in the local cattle. Nonetheless, the parasite was shown to exist in Jabalpur in native buffaloes and cross-bred cattle with the clinical signs in later cases The epizootiology of nasal schistosomiasis is different from that of hepatic schistosomiasis.
Though there have been lot of research papers, presidential addresses, few review articles and chapters on South Asian schistosomes and schistosomiasis since last hundred years , yet there was no book which could deal the subject in a comprehensive way.To fill up this gap, I have written book "Schistosomes and schistosomiasis in South Asia" which has been published in Springers India Pvt Ltd in June ,2012 and may be viewed by any one on the website www.springer.com The book comprises 12 chapters and even single chapter may be taken from the publisher.
I will be glad to correspond with any person/trust/organization who is interested to control schistosomiasis and other parasitological infections in our animals including dealing with zoonotic diseases.
Laboratory Work
Models. S.spindale is wide spread and causing great damage to livestock industry. Still it is less studied blood-fluke probably because of absence of a suitable laboratory model till recent time. Under an ICMR Project, compatibility of mice, rats, rabbits and guinea-pigs for S.spindale was studied taking parameters like percentage fluke recovery, sex ratio, egg load, viability of eggs. In contrast to earlier findings, guinea-pigs proved best suited for maintaining S.spindale in the laboratory followed by rabbits, mice and rats .
We have been able to develop Schistosoma nasale in the rabbit to adulthood with production of eggs and granuloma in its liver Thus, a good laboratory model has been developed which may be used for studying chemotherapy, immunology and pathology of Schistosoma nasale
Cercarial Identificartion. We demonstrated existence of five mammalian schistosome species at Jabalpur . However, the greatest impediment in epidemiological studies in such cases is the difficulty in identifying schistosome cercariae on morphological grounds alone. On the other hand, animal inoculation is not only time consuming but also expensive and laborious way of cercarial identification. Therefore, we examined various methods for differentiating S.incognitum, S.indicum, S.spindale and O.dattai cercarial species. We are successful in our endeavour as certain simple techniques led to identification of cercarial species with considerable accuracy. Amongst these, mention may be made of a staining technique for furcal rami which proved quite simple and most effective methodology. We may provide consultancy on this subject.
We have been able to develop Schistosoma nasale in the rabbit to adulthood with production of eggs and granuloma in its liver Thus, a good laboratory model has been developed which may be used for studying chemotherapy, immunology and pathology of Schistosoma nasale
Cercarial Identificartion. We demonstrated existence of five mammalian schistosome species at Jabalpur . However, the greatest impediment in epidemiological studies in such cases is the difficulty in identifying schistosome cercariae on morphological grounds alone. On the other hand, animal inoculation is not only time consuming but also expensive and laborious way of cercarial identification. Therefore, we examined various methods for differentiating S.incognitum, S.indicum, S.spindale and O.dattai cercarial species. We are successful in our endeavour as certain simple techniques led to identification of cercarial species with considerable accuracy. Amongst these, mention may be made of a staining technique for furcal rami which proved quite simple and most effective methodology. We may provide consultancy on this subject.
Technologies Developed
1. Infecting large animal. Infecting large animals by percutaneous method (Rabbit, Sheep, Goat, Pig, Cattle etc.) with schistosome cercariae for experimental work on chemotherapy, pathology, immunology or any other purpose has always been difficult. It required control of the animals with the use of sedatives and was much time consuming as individual animal has to be handled else there were chances of spoilage of the cercariae.
We have observed that the schistosome cercariae survive in the water with full biological activities even if kept in a polythene bag. This prompted us to put counted number of cercariae in polythene bag and tie it in paw of the Guinea pigs. To our surprise, all the cercariae penetrated the paw skin and the guinea pigs developed the infection. We repeated this technique by using ear pinna of the rabbit, tail of the pigs , and ear pinna of the goats. In all these animals, the schistosome infection developed with recovery of blood flukes which was not different from that of traditional method
2. Perfusion of animal. Recovery of the Schistosomes from killed animals is important either for confirming diagnosis or assessing chemotherapy, immunology or any other parameter on schistosomiasis. For accurate fluke recovery, a perfusion technique is always recommended which is being carried out by a peristaltic pump or any other such device.
In India we have used first time perfusion technique for recovery of the blood flukes . In the technique one automatic pipetting machine was used for perfusing the animals.This was suitable only for small animals and resulted in breaking of glass syringes due to neglect. Therefore, it is felt if automatic pipetting machine can be replaced by any other simple device or equipment. The trials with horizontal water pump commonly used in desert water coolers proved successful. Thus the technique showed two clear cut advantages over automatic pipetting machine.
(a) While automatic pipetting machine was useful only in rat & mice, the new technique with water pump was useful in all the animals of all sizes.
(b) The cost of horizontal water pump is only Rs. 600/- while that of automatic pipetting machine or peristaltic pump is 30,000=00 to 80,000/-.
3. Use of polythene bag. All over the world ,all the medical & veterinary Diagnostic laboratories are examining faecal samples for parasitic infections by using micro slide & cover slip. This traditional technique inherits following disadvantages.
(a) The slide dries up within one hour and it is important to check the sample within stipulated period.
(b) The slide cannot be kept as reference material as it spoils within a day or so. The slide cannot be dispatched outside the city by ordinary mail for taking second opinion of another expert. The cost of slide & cover slips is more than Rs. 1.5 /-
(c) We thought to device some simple technique which may rectify the above problems.
At last we were successful when processed faecal material was kept in small LDPE polythene bag whose opening end was sealed with an electric rod. We can observe all the helminthic eggs as well as protozoan cysts under microscope using 100, 400 magnification. The polythene bags may be stored for about a month and may be transported to any place by ordinary post. Additionally the cost of the polythene bags is not more than 25 paise.
4. Biological Control of fresh water Snails. Fresh water snails (Indoplanorbis exustus, & L.luteola and L. accuminata) are responsible for transmitting almost all fluke infections in India.Therefore, it is important to search out any biological control agent for these fresh water snails.
During our work, we developed a simple technique of keeping fresh water snails in the artificial pond.The conditions were simulating to natural conditions. The methodology was quiet well for 2 years. But after wards we observed diminishing number of snails and no new snails were coming up. A thorough investigation to the problem for about a year , revealed that one wingless aquatic insect was responsible for eating young snails.
The insects were carnivorous and feeding on snails under natural conditions. These were identified as nymphs of the dragon fly. Our repeated work have shown that these nymphets breed & develop favorably in the aquatic environment which is also favourable for the fresh water snails. Since both the organisms are surviving in the same environment ,it will be more feasible & appropriate to develop nymphets as biological control agent for the fresh water snails. These nymphets are known to feed on mosquito larvae/ pupae ( we have confirmed the same) and other insects. However, feeding on fresh water snails appears our original observation. The work may be explored further for control of fluke infections. We may provide consultancy on this subject.
Other Parasites
EAR-SORE IN INDIA.
Stephanofilariasis is mainly caused by two species. Stephanofilaria assamensis causes hump –sore in cattle and occurs mainly in Assam,West Bengal, Orissa and Andaman islands. On the otherhand, S.zaheeri causes ear-sore in buffaloes and more widespread in India .
Ear-sore ,caused by Stephanofilaria zaheeri , is found in proportion to age of the buffaloes reaching to 90-100% in old animals. Apparently healthy buffalo skins also possess adult males. It is futile to conduct skin biopsy for judging drug efficacy because of a lower filarial concentration even in clinical cases. In.vitro testing showed malathion to possess anti filarial activity too. Interestingly, all the cattle examined grossly or histopathologically were non compatible to S.zaheeri. These findings and our knowledge on Stephanofilaria have been discussed in our review on Stephnofilarial dermatitis in India (Vet. Res. Comm, 8:93. 1984).
SARCOCYSTOSIS IN INDIA.
Sarcocystosis has been demonstrated to occur in almost all domestic animals in India where dog or cat is acting as final host of the parasite. Though mature sarcocysts have been shown In almost every animal species in nature, its pathogenesis leading to death or abortion either in sheep goat or cattle has not been proved in natural cases.
We developed a method for detecting developing sarcocysts in experimentally infected goats and a method for collecting large number of sporocysts from experimentally infected dogs. The transmission potential of dogs was assessed The life cycle and associated pathogenesis of Sarcocystis capracanis has been studied in India.
Importantly , Sarcocysts of Sarcocystis spp. were reported by us from albino rats from India, which may be tried to develop as a laboratory model for studying sarcocystosis
WILD LIFE PARASITES.
A survey of wild animals of Kanha National Park, Kanha, Madhya Pradesh was undertaken for parasitic infections. The survey revealed presence of Toxocara, Ascaris, Hookworms, Taenia, amphistomes, and Fasciola in wild animals which included swamp deer, spotted dear, elephants, tigers and caniids. Interestingly, the tigers and a wild cat were excreting Paragonimus eggs in their faeces beside other eggs. A deer-ked bite in man at Kanha was also reported by us .Recently we have observed Bivitellobilharzia nairi infection in 8 out of 25 elephants stationed at Kanha national Park suggesting establishment of the focus in the area which is not a natural habitat of the elephants .
Stephanofilariasis is mainly caused by two species. Stephanofilaria assamensis causes hump –sore in cattle and occurs mainly in Assam,West Bengal, Orissa and Andaman islands. On the otherhand, S.zaheeri causes ear-sore in buffaloes and more widespread in India .
Ear-sore ,caused by Stephanofilaria zaheeri , is found in proportion to age of the buffaloes reaching to 90-100% in old animals. Apparently healthy buffalo skins also possess adult males. It is futile to conduct skin biopsy for judging drug efficacy because of a lower filarial concentration even in clinical cases. In.vitro testing showed malathion to possess anti filarial activity too. Interestingly, all the cattle examined grossly or histopathologically were non compatible to S.zaheeri. These findings and our knowledge on Stephanofilaria have been discussed in our review on Stephnofilarial dermatitis in India (Vet. Res. Comm, 8:93. 1984).
SARCOCYSTOSIS IN INDIA.
Sarcocystosis has been demonstrated to occur in almost all domestic animals in India where dog or cat is acting as final host of the parasite. Though mature sarcocysts have been shown In almost every animal species in nature, its pathogenesis leading to death or abortion either in sheep goat or cattle has not been proved in natural cases.
We developed a method for detecting developing sarcocysts in experimentally infected goats and a method for collecting large number of sporocysts from experimentally infected dogs. The transmission potential of dogs was assessed The life cycle and associated pathogenesis of Sarcocystis capracanis has been studied in India.
Importantly , Sarcocysts of Sarcocystis spp. were reported by us from albino rats from India, which may be tried to develop as a laboratory model for studying sarcocystosis
WILD LIFE PARASITES.
A survey of wild animals of Kanha National Park, Kanha, Madhya Pradesh was undertaken for parasitic infections. The survey revealed presence of Toxocara, Ascaris, Hookworms, Taenia, amphistomes, and Fasciola in wild animals which included swamp deer, spotted dear, elephants, tigers and caniids. Interestingly, the tigers and a wild cat were excreting Paragonimus eggs in their faeces beside other eggs. A deer-ked bite in man at Kanha was also reported by us .Recently we have observed Bivitellobilharzia nairi infection in 8 out of 25 elephants stationed at Kanha national Park suggesting establishment of the focus in the area which is not a natural habitat of the elephants .
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