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.
3 comments:
Great field work, on the next great advancement in medicine since hygiene, antibiotics and common sence in medicine.
sir can you tell me what are the genes present in this diease.
sir it will be helpful to do futher research in this water born diease even i am looking forward to research in this.so sir can you help me,what are the genes present in this diease.
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