162 TRANSACTIONSOF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE,- VOL. 70. No. 2, 1976.
Corresponde’nce To the Editor
Care for overseas patients The Rt. Hon. Mrs. Barbara Castle, M.P., Secretary of State for Social Services, Department of Health and Social Security, Alexander Fleming House, Elephant and Castle, London, SE1
Dear Mrs. Castle, I have had several discussions with my colleagues concerning your letter to me dated 20th February and we all greatly appreciate your willingness to ensure that expertise within academic units at the Hospital for Tropical Diseases, London, and the Tropical Unit, the Royal Victoria Infirmary, Liverpool, will continue to be available to those from overseas seeking medical help. I would also like to mention that medical research and teaching are greatly strengthened by the admission to hospitals, such as these, of persons who in the first instance have been seen by one of my collegues having a part-time consultant contract and who, when admitted to the hospital, come in as private patients. I sincerely hope that it will be possible for you to ensure in the negotiations ahead that this source of strength is maintained. Yours sincerely, A. W. WOODRUFF Medical Unit, Hospital for Tropical Diseases, London, NW1 25th June 1975
Dear Professor Woodruff, ’ Thank you for your letter of 25th June, about the position of patients from overseas seeking specialised treatment in academic units after pay beds are phased out of NHS hospitals. Although the Government’s policy is the separation of private practice from NHS hospitals, as I told the House on 5th May it is our intention to make special arrangements under which overseas patients will continue to be able, in certain circumstances, to come to this country for specialised treatment in NHS hospitals on payment of the full cost. We are still considering details of future arrangements for the treatment of such overseas patients, and will bear in mind the particular problems of specialist units for the treatment of tropical diseases in our deliberations. Sincerely, BARBARA CASTLE Department of Health and Social Security, London, SE1 15th July 1975
Dear Mrs. Castle, Thank you very much for your letter of the 15th July. I know that all members of the medical staff of this
hospital will be greatly reassured by the kind consideration which you have given this matter. Yours sincerely, A. W. WOODRUFF Medical Unit, Hospital for Tropical Diseases, London, N Wl 23rd July 1975
Observations concerning the parasitic load, duration of infection and clinical manifestations in strongyloidiasis ‘SIR-In a previous paper (DANCESCU,1968) I described a method for evaluating parasitic intensity in strongyloidiasis by means of cultures on coal in closed boxes. Larvae being unequally distributed in faeces (TANAKA, 1966), the accuracy of the method is not complete, but the method has given very consistent results on examinations repeated three to 12 times in the course of a year. In cultures of the Romania strain of Strongyloides stercoralis, the rhabditiform larvae develop mainly into filariform larvae and very rarely into freeliving adults (heterogeneous generation): therefore there is no multiplication in the coal culture. This contrasts with the behaviour of the tropical strain. In native Romanian strongyloidiasis it may be assumed, therefore, that there is a relation between the worm burden (number of adults harboured by an individual) and the parasitic intensity (number of larvae in a unit weight of faeces, as judged from coal culture). In our investigations on S. stercoralis carriers, we studied the parasitic intensity in relation to other factors such as the age of patients and clinical manifestations. Most of the individuals who show a high parasitic intensity are children and young persons. Thus more than 73 % of the parasite carriers who were between five and 12 years old had several hundred to over a thousand larvae in standard culture preparations on coal. Only 32 % of the individuals aged between 20 and 78 years had a high parasitic intensity, and, these never more than several hundreds. In young persons asymptomatic and oligosymptomatic forms are more frequent. Such clinical forms diminish as the parasite carriers advance in age. The clinical picture varies also according to the age factor. Thus in young people the clinical forms with digestive symptoms predominated, while in the aged neuropsychic manifestations were commoner. We assumed that, in most cases, the duration of the parasitosis can be considered as dependent upon the age. Therefore it seems that the equilibrium between the reaction and the tolerance of the organism against S. stercoralis varies in relation with the age of infected
CORRESPONDENCE
individuals and the duration of the disease. The more longstanding the parasitosis, the more diminished is the parasitic intensity, while the clinical manifestations are more systematized and more abundant, the extradigestive ones predominating. This phenomenon is known in general parasitology, but I have the impression that it has not been pointed out in connexion with strongyloidiasis previously, perhaps because most of the studies of this disease have been made in warm countries, where the abundance of heterogenetic generations and the consequent multiplication of the parasites, prevents the evaluation of parasitic intensity. I am, etc., PAULDANCESCU
Faculty of Medicine, Bd. Dr. P. Gvoxa 8, Bucharest 35, Romania 25th April, 1975 References Dancescu, P. (1968). Investigations on the intensity of the infection in a strongyloidiasis focus: the coal culture method. Transactions of the Royal Society of Tropical Medicine and Hygiene, 62, 490495. Tanaka, H. (1966). Genus Strongyloides. Progressive Medicine and Ptirasitology, Japan, 3, 592-
Trypanosomiasis cruzi in mice with trichinosis St&-In a previous letter in this journal it was reported that trichinosis in rats suppressed the parasitaemia of superimposed Trypanosoma equiperdum or T. lewisi infections (MEEROVITCH and ACKERMAN, 1974). We have attempted to extend this finding by determining whether Tvichinella infections would enhance the survival of mice infected with the human pathogen T. cruzi. In one experiment, trichinous mice (inoculated 31 days earlier with 200 T. spiralis larvae each) and non-trichinous mice were inoculated subcutaneously with a Brazilian strain of T. cruzi. The mice used were CFl females weighing approximately 20 g. They had been randomly assigned to groups of five mice each at the beginning of the experiment, and were held under comparable conditions throughout. Among mice given 1,000 T. cruzi each, the mortality rate over a 60-day observation period was 35 ‘A for 20 trichinous mice and 60 % for 20 nontrichinous mice. Among the same numbers of mice given 10,000 T. cruzi each, the mortality rate was 70% for trichinous mice and 90% for non-tricbinous. Although the mortality rate was lower in trichinous mice, the difference is not statistically significant (Mann-Whitney U test) and those trichinous mice that died had a mean survival time (26.1 days and 22.6 days for 1,000 and 10,000 T. cuuzi, respectively) that was not different from the survival time of non-trichinous mice (26.3 days and 22.3 days). Examination of wet mounts of tail blood of each mouse on day 11 or 14 of infection, revealed at least as many trypanosomes per microscope field in the case of trichinous mice as in non-trichinous. In a second experiment, trichinous mice (inoculated 28 days earlier with 250 Trichinella larvae each) and nontrichinous mice were inoculated subcutaneously with 50,000 organisms of the same strain of T. cruzi. All of the mice died within three weeks. The mean survival time of the trichinous mice (15.2k2.5 days) was not signifi-
163
cantly different from that of the non-trichinous mice (16,2i-2.3 days). Both of the above experiments included mice infected with Trichinella alone and no deaths were recorded in those groups. In the first experiment the Trichinellainfected mice weighed 15 ‘A less than the non-trichinous mice at the time of T. cvuzi inoculation, and in the second experiment they weighed 27 % less than the non-trichinous mice (an expected result of the Trichinella infection). At the termination of the first experiment, digestion of each surviving Trichinella-inoculated mouse confirmed the infection in all cases, and yielded a mean of 43,600*4,600 larvae per mouse in the Trichinella-only group. It is possible that the relatively lower weight of the trichinous mice made them significantly more susceptible to the lethal effect of T. cruzi infection and thereby masked a protective effect that would otherwise have been evident. Further, the small groups of mice used in the expectation of a strong degree of protection do not permit us to rule out the occurrence of a modest degree of protection. Nevertheless, it is clear that within the limitations of the experimental circumstances, trichinosis failed to provide significant protection against the lethal effect of T. cruzi in mice. We are, etc., WILLIAM C. CAMPBELL CHRISTINE M. MALANGA JOYCE A. CONROY Merck Institute for Therapeutic Research, Rahway, New Jersey 07065 23rd May 1975 Reference Meerovitch, E. & Ackerman, S. J. (1974). Trypanosomiasis in rats with trichinosis. Transactions of the Royal Society of Tropical Medicine and Hygiene, 68, 417.
The treatment of congenital trypanosomiasis SIR-In a recent paper a case of congenital trypanosomiasis was reported from Nigeria. The case ended fatally, although suramin therapy was attempted. The author (OLOWE, 1975) commented on an apparent lack of information concerning the treatment of this condition. In Zambia, a transplacentally infected premature baby, weighing I.7 kg, was successfully treated (BUYST, 1973). The child was born in an endemo-epidemic area of Trypanosoma rhodesiensesleeping sickness on the northern edge of the Luangwa flybelt (BUYST, 1974), and was collected at the village when he was only two days old. During the 72 km journey to hospital the general condition of the child was very poor and death seemed imminent. A blood smear taken on admission was positive for trypanosomes and the next day (day four) the cerebrospinal fluid revealed trypanosomes and 44 leucocytes per mm3 (92 % lymphocytes, 8 % neutrophils). The child was lethargic, slightly jaundiced and anaemic (Hb: 7.3 g %), and showed signs of prematurity and eye infection. The mother also had a positive blood smear and her cerebrospinal fluid contained trypanosomes and 67 leucocytes per mm3 (88 % lymphocytes, 12 % neutrophils). Her blood group was A Rhesus positive. The child received penicillin, chloroquine, parenteral
Corresponde’nce To the Editor
Care for overseas patients The Rt. Hon. Mrs. Barbara Castle, M.P., Secretary of State for Social Services, Department of Health and Social Security, Alexander Fleming House, Elephant and Castle, London, SE1
Dear Mrs. Castle, I have had several discussions with my colleagues concerning your letter to me dated 20th February and we all greatly appreciate your willingness to ensure that expertise within academic units at the Hospital for Tropical Diseases, London, and the Tropical Unit, the Royal Victoria Infirmary, Liverpool, will continue to be available to those from overseas seeking medical help. I would also like to mention that medical research and teaching are greatly strengthened by the admission to hospitals, such as these, of persons who in the first instance have been seen by one of my collegues having a part-time consultant contract and who, when admitted to the hospital, come in as private patients. I sincerely hope that it will be possible for you to ensure in the negotiations ahead that this source of strength is maintained. Yours sincerely, A. W. WOODRUFF Medical Unit, Hospital for Tropical Diseases, London, NW1 25th June 1975
Dear Professor Woodruff, ’ Thank you for your letter of 25th June, about the position of patients from overseas seeking specialised treatment in academic units after pay beds are phased out of NHS hospitals. Although the Government’s policy is the separation of private practice from NHS hospitals, as I told the House on 5th May it is our intention to make special arrangements under which overseas patients will continue to be able, in certain circumstances, to come to this country for specialised treatment in NHS hospitals on payment of the full cost. We are still considering details of future arrangements for the treatment of such overseas patients, and will bear in mind the particular problems of specialist units for the treatment of tropical diseases in our deliberations. Sincerely, BARBARA CASTLE Department of Health and Social Security, London, SE1 15th July 1975
Dear Mrs. Castle, Thank you very much for your letter of the 15th July. I know that all members of the medical staff of this
hospital will be greatly reassured by the kind consideration which you have given this matter. Yours sincerely, A. W. WOODRUFF Medical Unit, Hospital for Tropical Diseases, London, N Wl 23rd July 1975
Observations concerning the parasitic load, duration of infection and clinical manifestations in strongyloidiasis ‘SIR-In a previous paper (DANCESCU,1968) I described a method for evaluating parasitic intensity in strongyloidiasis by means of cultures on coal in closed boxes. Larvae being unequally distributed in faeces (TANAKA, 1966), the accuracy of the method is not complete, but the method has given very consistent results on examinations repeated three to 12 times in the course of a year. In cultures of the Romania strain of Strongyloides stercoralis, the rhabditiform larvae develop mainly into filariform larvae and very rarely into freeliving adults (heterogeneous generation): therefore there is no multiplication in the coal culture. This contrasts with the behaviour of the tropical strain. In native Romanian strongyloidiasis it may be assumed, therefore, that there is a relation between the worm burden (number of adults harboured by an individual) and the parasitic intensity (number of larvae in a unit weight of faeces, as judged from coal culture). In our investigations on S. stercoralis carriers, we studied the parasitic intensity in relation to other factors such as the age of patients and clinical manifestations. Most of the individuals who show a high parasitic intensity are children and young persons. Thus more than 73 % of the parasite carriers who were between five and 12 years old had several hundred to over a thousand larvae in standard culture preparations on coal. Only 32 % of the individuals aged between 20 and 78 years had a high parasitic intensity, and, these never more than several hundreds. In young persons asymptomatic and oligosymptomatic forms are more frequent. Such clinical forms diminish as the parasite carriers advance in age. The clinical picture varies also according to the age factor. Thus in young people the clinical forms with digestive symptoms predominated, while in the aged neuropsychic manifestations were commoner. We assumed that, in most cases, the duration of the parasitosis can be considered as dependent upon the age. Therefore it seems that the equilibrium between the reaction and the tolerance of the organism against S. stercoralis varies in relation with the age of infected
CORRESPONDENCE
individuals and the duration of the disease. The more longstanding the parasitosis, the more diminished is the parasitic intensity, while the clinical manifestations are more systematized and more abundant, the extradigestive ones predominating. This phenomenon is known in general parasitology, but I have the impression that it has not been pointed out in connexion with strongyloidiasis previously, perhaps because most of the studies of this disease have been made in warm countries, where the abundance of heterogenetic generations and the consequent multiplication of the parasites, prevents the evaluation of parasitic intensity. I am, etc., PAULDANCESCU
Faculty of Medicine, Bd. Dr. P. Gvoxa 8, Bucharest 35, Romania 25th April, 1975 References Dancescu, P. (1968). Investigations on the intensity of the infection in a strongyloidiasis focus: the coal culture method. Transactions of the Royal Society of Tropical Medicine and Hygiene, 62, 490495. Tanaka, H. (1966). Genus Strongyloides. Progressive Medicine and Ptirasitology, Japan, 3, 592-
Trypanosomiasis cruzi in mice with trichinosis St&-In a previous letter in this journal it was reported that trichinosis in rats suppressed the parasitaemia of superimposed Trypanosoma equiperdum or T. lewisi infections (MEEROVITCH and ACKERMAN, 1974). We have attempted to extend this finding by determining whether Tvichinella infections would enhance the survival of mice infected with the human pathogen T. cruzi. In one experiment, trichinous mice (inoculated 31 days earlier with 200 T. spiralis larvae each) and non-trichinous mice were inoculated subcutaneously with a Brazilian strain of T. cruzi. The mice used were CFl females weighing approximately 20 g. They had been randomly assigned to groups of five mice each at the beginning of the experiment, and were held under comparable conditions throughout. Among mice given 1,000 T. cruzi each, the mortality rate over a 60-day observation period was 35 ‘A for 20 trichinous mice and 60 % for 20 nontrichinous mice. Among the same numbers of mice given 10,000 T. cruzi each, the mortality rate was 70% for trichinous mice and 90% for non-tricbinous. Although the mortality rate was lower in trichinous mice, the difference is not statistically significant (Mann-Whitney U test) and those trichinous mice that died had a mean survival time (26.1 days and 22.6 days for 1,000 and 10,000 T. cuuzi, respectively) that was not different from the survival time of non-trichinous mice (26.3 days and 22.3 days). Examination of wet mounts of tail blood of each mouse on day 11 or 14 of infection, revealed at least as many trypanosomes per microscope field in the case of trichinous mice as in non-trichinous. In a second experiment, trichinous mice (inoculated 28 days earlier with 250 Trichinella larvae each) and nontrichinous mice were inoculated subcutaneously with 50,000 organisms of the same strain of T. cruzi. All of the mice died within three weeks. The mean survival time of the trichinous mice (15.2k2.5 days) was not signifi-
163
cantly different from that of the non-trichinous mice (16,2i-2.3 days). Both of the above experiments included mice infected with Trichinella alone and no deaths were recorded in those groups. In the first experiment the Trichinellainfected mice weighed 15 ‘A less than the non-trichinous mice at the time of T. cvuzi inoculation, and in the second experiment they weighed 27 % less than the non-trichinous mice (an expected result of the Trichinella infection). At the termination of the first experiment, digestion of each surviving Trichinella-inoculated mouse confirmed the infection in all cases, and yielded a mean of 43,600*4,600 larvae per mouse in the Trichinella-only group. It is possible that the relatively lower weight of the trichinous mice made them significantly more susceptible to the lethal effect of T. cruzi infection and thereby masked a protective effect that would otherwise have been evident. Further, the small groups of mice used in the expectation of a strong degree of protection do not permit us to rule out the occurrence of a modest degree of protection. Nevertheless, it is clear that within the limitations of the experimental circumstances, trichinosis failed to provide significant protection against the lethal effect of T. cruzi in mice. We are, etc., WILLIAM C. CAMPBELL CHRISTINE M. MALANGA JOYCE A. CONROY Merck Institute for Therapeutic Research, Rahway, New Jersey 07065 23rd May 1975 Reference Meerovitch, E. & Ackerman, S. J. (1974). Trypanosomiasis in rats with trichinosis. Transactions of the Royal Society of Tropical Medicine and Hygiene, 68, 417.
The treatment of congenital trypanosomiasis SIR-In a recent paper a case of congenital trypanosomiasis was reported from Nigeria. The case ended fatally, although suramin therapy was attempted. The author (OLOWE, 1975) commented on an apparent lack of information concerning the treatment of this condition. In Zambia, a transplacentally infected premature baby, weighing I.7 kg, was successfully treated (BUYST, 1973). The child was born in an endemo-epidemic area of Trypanosoma rhodesiensesleeping sickness on the northern edge of the Luangwa flybelt (BUYST, 1974), and was collected at the village when he was only two days old. During the 72 km journey to hospital the general condition of the child was very poor and death seemed imminent. A blood smear taken on admission was positive for trypanosomes and the next day (day four) the cerebrospinal fluid revealed trypanosomes and 44 leucocytes per mm3 (92 % lymphocytes, 8 % neutrophils). The child was lethargic, slightly jaundiced and anaemic (Hb: 7.3 g %), and showed signs of prematurity and eye infection. The mother also had a positive blood smear and her cerebrospinal fluid contained trypanosomes and 67 leucocytes per mm3 (88 % lymphocytes, 12 % neutrophils). Her blood group was A Rhesus positive. The child received penicillin, chloroquine, parenteral
