Showing papers in "Transactions of The Royal Society of Tropical Medicine and Hygiene in 1967"
TL;DR: It is concluded that the main stimulus in this host-parasite system is from antigens associated with the living adult worm, but not associated with egg production, and it is unlikely that the egg plays an important role in inducing resistance.
Abstract: It has been established that a single exposure to as few as 25 normal cercariae of Schistosoma mansoni was sufficient to induce a good resistance in each of 2 rhesus monkeys when they were challenged 17 weeks later. Since a single exposure to 20,000 cercariae irradiated at 2000 r failed to do so, it seems likely that the migratory stages contribute little to the development of resistance, and that the main stimulus is associated with the adult worm. This idea has been confirmed by transferring established adult worms directly into the hepatic portal system of normal monkeys. On subsequent challenge 8–14 weeks later, several monkeys were almost completely resistant, and all monkeys had received living worms suffered less severely than the controls. Worms from monkey, hamster and mouse donors all induced resistance. Worms cut in two immediately before transfer induced resistance, but worms killed by freezing did not. The “half-worms” from mouse donors were found to survive for at least 10 weeks; only the anterior portions survived but these rounded off and in a small proportion of females egg production recommenced. There was no correlation between the egg production of the transferred worms and the degree of resistance induced. This, together with the failure to induce resistance by injecting approximately 500,000 live eggs into the mesenteric veins, makes it unlikely that the egg plays an important role in inducing resistance. It must be concluded that the main stimulus in this host-parasite system is from antigens associated with the living adult worm, but not associated with egg production. The fate of the transferred worms seems to depend upon the species of the donor. Worms transferred from monkeys to monkeys survive well and continue to produce eggs; worms from hamsters survive poorly although they are still able to induce resistance. Worms transferred from mice suffer an initial check in egg production but later recover fully. Apparently the worms become adapted to their original host species. On transfer, the environment is changed for the worms from the mice and hamsters. The worms from mice eventually adapt to the new environment; the worms from hamsters fail to do so.
156 citations
TL;DR: The absence of severe or diffuse fibrosis of the intestinal submucosa and the decreasing incidence of infection with increasing age in cases, diagnosed by tissue examination, indicate that increased egg retention with decreased excretion of eggs in the faeces is an unlikely explanation for decreased egg excretion noted in older persons.
Abstract: The pathological lesions associated with schistosome infection in Bahia, Brazil, were reviewed in an attempt to clarify the nature and prevalence of the lesions caused by S. mansoni , and to define better our material for comparison with that from other centres. The prevalence of various lesions possibly caused by schistosome infection was determined in cadavers with and without S. mansoni infection. The records of 1435 consecutive autopsies were reviewed, 502 of which showed the infection. In 105 of these, Symmers's clay-pipe-stem fibrosis of the liver was present. All cases of portal hypertension attributed to schistosomiasis had Symmers's fibrosis, and nearly all cases of Symmers's fibrosis had symptoms and signs of marked portal hypertension. Schistosomal pulmonary arteritis and cor pulmonale were frequent in cases of Symmers's fibrosis, but in those without Symmers's fibrosis no unequivocal cases of cor pulmonale caused by schistosomiasis were identified. Another positive finding was segmental fibrous thickening of the colonic serosa and of the mesocolon, lesions most frequently seen in cases with Symmers's fibrosis. Fibrosis of the intestinal submucosa was rare. The absence of severe or diffuse fibrosis of the intestinal submucosa and the decreasing incidence of infection with increasing age in our cases, diagnosed by tissue examination, indicate that increased egg retention with decreased excretion of eggs in the faeces is, by itself, an unlikely explanation for decreased egg excretion noted in older persons. Death of worms or a decrease in egg production are hypotheses more consistent with the present observations. A number of other lesions showed no positive correlation with schistosome infection. These included cirrhosis, hepatoma, ulcerative intestinal lesions and clinically significant colonic polyposis. Thus Symmers's fibrosis was the most significant lesion caused by schistosome infection were found almost exclusively in the cases also having Symmers's fibrosis. Compared with subjects with cirrhosis, more of those with Symmers's fibrosis died from rupture of oesophago-gastric varices and showed lower indices of hepatic coma, jaundice, oedema and ascites. Liver and spleen sizes were larger in subjects with Symmers's fibrosis than in those with cirrhosis. Portal vein thrombosis was more frequent in cases with. Symmers's fibrosis, and was very frequent in patients who had been subjected to surgery.
130 citations
TL;DR: Basic causal mechanisms underlying some features of filarial disease are discussed in relation to the filarial life cycle, the lesions produced by worms and their products, the pattern of lymphatic drainage, and the functional physiology of the lymphatic system.
Abstract: Brugia pahangi infections in the lymph nodes of cats have been studied in serial sections stained with H & E at intervals of from 3 days to 16 1 2 months; material from a few dogs was also examined. The pathological changes are described and discussed in relation to the life cycle of the agent. Reactions were found to: living and dead larvae (third and fourth stage); moulting fluids and moulted cuticles of the third and fourth moults; uterine secretions, infertile eggs and microfilariae; and finally to living and dead adult worms. Pathological changes in dogs are strikingly more rapid and extreme than in cats. Basic causal mechanisms underlying some features of filarial disease are discussed in relation to the filarial life cycle, the lesions produced by worms and their products, the pattern of lymphatic drainage, and the functional physiology of the lymphatic system.
77 citations
TL;DR: The idea that Toxoplasma gondii can be transmitted within Toxocara cati ova is supported by the fact that the toxoplasm infections can be filtered from a positive inoculum by using a sieve whose mesh size is small enough to retain the nematode ova.
Abstract: A cat infected with the nematode, Toxocara cati, and another which was nematode-negative, were both fed with the cystic forms of Toxoplasma gondii. The cat infected with Toxocara cati produced faeces capable of infecting mice with Toxoplasma; the Toxocara-negative cat did not. The Toxocara-negative cat was then infected with this nematode and the positive cat was treated with an anthelmintic to remove the worms. Both cats were again fed with Toxoplasma cysts; once again, the faeces containing the Toxocara cati ova infected mice with Toxoplasma, while those negative for Toxocara did not. These experiments support the idea that Toxoplasma gondii can be transmitted within Toxocara cati ova. Additional support has been provided by the fact that the toxoplasm infections can be filtered from a positive inoculum by using a sieve whose mesh size is small enough to retain the nematode ova. Evidence is given that this transmission mechanism could be responsible for avian infections.
62 citations
TL;DR: Exflagellating microgametocytes and microGametes of Plasmodium berghei, P. cynomolgi, Hepatocystis kochi and Leucocytozoon marchouxi were examined in the electron microscope and revealed the presence of an internal flagellar axial filament complex, an elongated nucleus and a pellicle.
Abstract: Exflagellating microgametocytes and microgametes of Plasmodium berghei, P. cynomolgi, Hepatocystis kochi and Leucocytozoon marchouxi were examined in the electron microscope. The morphology was similar in all species.
Sections through the exflagellating gametocytes revealed 3 zones: (a) a light outermost envelope (not always present) representing the degenerating erythrocyte; (b) a dense region corresponding to the cytoplasm of the parasite and containing Golgi apparatus, endoplasmic reticulum, mitochondria, pigment and developing flagella; and (c) the nucleus undergoing endomitotic division, the 8 daughter nuclei eventually moving to the point of emergence of the gametes.
Shadow-cast replicas of microgametes showed elongated bodies without free flagella.
Sections of microgametes revealed the presence of an internal flagellar axial filament complex extending throughout their length, an elongated nucleus and a pellicle. The complex was made up of the typical 9 + 2 filaments with 9 radial spokes.
The fundamental difference between the (short) microgamete of the Eimeriidea with 2 free flagella and the (long) microgamete of malaria parasites with no free flagellum is pointed out. A diagrammatic scheme of development of the latter is given.
56 citations
TL;DR: An elaborate follow-up procedure must be adopted before a new drug discovered by screening can be prepared and passed for clinical trial, and the “Quinine Index” should be replaced by a “Chloroquine Index".
Abstract: Largely because of the emergence of P. falciparum strains resistant to modern antimalarial drugs such as chloroquine, there is a new surge of interest in malaria chemotherapy. Various in vitro systems for drug screening are reviewed. There is some hope that automated techniques may be of value in the future. Drug screening in the mosquito vectors can give useful leads to compounds with sporontocidal action, and is relatively cheap and easy. P. berghei in the albino mouse is replacing older laboratory models with various avian malarias for in vivo screening. Drug resistant as well as sensitive lines of P. berghei are available for drug screening, and resulting data may readily be interpolated in terms of chemotherapy of P. falciparum infection in man. Standardized techniques which must be adopted with the P. berghei test are discussed. The “Quinine Index” should be replaced by a “Chloroquine Index.” An elaborate follow-up procedure must be adopted before a new drug discovered by screening can be prepared and passed for clinical trial.
52 citations
TL;DR: Successful agglutination tests could be performed consistently with any of these particles provided formalin treatment was omitted, and prior treatment with formalin rendered erythrocytes difficult to sensitize.
Abstract: Naked sheep erythrocytes, tanned sheep erythrocytes, tanned human erythrocytes of Group O, tanned and formolized sheep erythrocytes and latex particles were sensitized with antigens derived from 8 strains of Leishmania spp. and used in agglutination tests with various antisera and immune sera. Sensitized erythrocytes were formolized and also used in agglutination tests. Successful agglutination tests could be performed consistently with any of these particles provided formalin treatment was omitted. Prior treatment with formalin rendered erythrocytes difficult to sensitize. Formalin treatment of sensitized erythrocytes caused auto-agglutination. The tests with various sera and various absorbed sera revealed serological differences between the strains used. A strain of Leishmania from Panama was shown to be quite distinct from L. mexicana of British Honduras and L. braziliensis of Brazil, and also to be distinct from 2 strains of Leishmania from Costa Rica. The two Costa Rican strains also represented distinct serotypes. Serological differences were detected between L. donovani from India and L. donovani from Kenya. With these tests no serological difference was detected between L. donovani (post-kala-azar dermal leishmanoid) from India and L. tropica from Israel, or between L. braziliensis of Brazil and one strain of so-called L. pifanoi from Brazil.
49 citations
TL;DR: There is some evidence that biochemical identification of salmonellae and routine Widal agglutination tests were not suitable laboratory procedures for definite identification, and the patients showed dramatic and convincing clinical response to chloromycetin, without relapses.
Abstract: 35 cases of prolonged septicaemic salmonellosis have been described in the State of Minas Gerais, Brazil, in recent years. The following points are emphasized:
1.
1. This salmonellosis does not represent a prolonged course of classical typhoid fever, but exhibits a clinical picture of a reticulo-endotheliosis closely related to that of kala-azar.
2.
2. Prolonged septicaemia is one of the most constant characteristics of the disease, and differs from those severe and lethal, as well as from the benign ambulatory, types observed in typhoid fever.
3.
3. Through serological typing of blood cultures, the following salmonellae were implicated in the infections: S. typhi, S. newport, S. panama, S. dublin, S. anatum, S. paratyphi A, S. paratyphi C, S. cholerae-suis, S. cholerae-suis var. kunzendorf, S. derby and S. montevideo.
4.
4. There is some evidence that biochemical identification of salmonellae and routine Widal agglutination tests were not suitable laboratory procedures for definite identification.
5.
5. The patients showed dramatic and convincing clinical response to chloromycetin, without relapses.
6.
6. Schistosoma mansoni infection was constant in these cases, but there is no convincing proof to evaluate the role it plays in the pathogenesis of septicaemic salmonellosis of protracted course.
44 citations
TL;DR: 4 geographical strains of Schistosoma mansoni, Puerto Rican, Brazilian, Egyptian and Tanzanian, each maintained in its local snail host, were studied in mice, finding the Puerto Rican strain to be most virulent in this regard.
Abstract: 4 geographical strains of Schistosoma mansoni, Puerto Rican, Brazilian, Egyptian and Tanzanian, each maintained in its local snail host, were studied in mice. On exposure to a given number of cercariae the animals infected with the Puerto Rican strain developed the largest number of worms, followed by the Egyptian strain and then by the Tanzanian and Brazilian strains. The production of liver disease was studied in mice each harbouring only one pair of worms. The Brazilian and Puerto Rican strains appeared to be most virulent in this regard, the Egyptian strain causing the least severe liver reaction and the Tanzanian strain producing the fewest eggs.
43 citations
TL;DR: Evidence of the effects of the state of maturity of the intra-molluscan phases of the infection on success of the cercariae is presented, and the quantitative distribution of parasite eggs in the host tissues is described.
Abstract: Some of the characteristics of a strain of Schistosoma haematobium from Natal in experimental infections in hamsters are described. Evidence of the effects of the state of maturity of the intra-molluscan phases of the infection on success of the cercariae is presented. Growth curves for the adult worms from the 90th day of infection to the 170th are given, and the retarded growth of unpaired males in the liver is discussed. The quantitative distribution of parasite eggs in the host tissues is described. An approximate figure for the daily egg output of individual female worms has been calculated. The importance of the influence of individual hosts, both on growth rates and egg production of their parasites, is stressed.
43 citations
TL;DR: An investigation of a possible relationship between Diphyllobothrium (fish tapeworm) infection and microcytic anaemia among Eskimos was carried out during 1957–1958 at the village of Hooper Bay in western Alaska, and infections did not contribute to anaemia in residents of this region.
Abstract: An investigation of a possible relationship between Diphyllobothrium (fish tapeworm) infection and microcytic anaemia among Eskimos was carried out during 1957–1958 at the village of Hooper Bay in western Alaska. Such infections did not contribute to anaemia in residents of this region, a finding in agreement with those of Totterman 1947 in Finland. Species of diphyllobothriid cestodes recorded from the lower Kuskokwim River region are listed, and other helminths recorded from man in this area are briefly discussed. Schistocephalus solidus (Mueller 1776) is reported from man, apparently for the first time.
TL;DR: It is suggested that the extremely virulent nature of T. brucei in the chimpanzee may be a means of distinguishing this species from T. rhodesiense, but more evidence is needed concerning other strains, host variations and the effect of intercurrent disease.
Abstract: Trypanosoma brucei, T. rhodesiense and T. gambiense were transmitted by Glossina palpalis to 3 chimpanzees; the strain of T. brucei was shown to be non-infective to man. High parasitaemias developed in the chimpanzee infected with T. brucei , and 14 days after the infective fly had fed trypanosomes were seen in the central nervous system. At this stage the animal was acutely ill and the erythrocyte sedimentation rate had increased; there was only a slight fall in the haemoglobin value. The chimpanzee appeared to be about to die but was cured by treatment with melarsen-oxide- bal . The infection with T. rhodesiense showed a fluctuating parasitaemia and had no apparent ill effect upon the chimpanzee for about one month after the infective feed. The general condition of the animal then deteriorated, and 44 days after infection the erythrocyte sedimentation rate had increased considerably and there was a marked anaemia; trypanosomes had invaded the central nervous system. The chimpanzee died while being anaesthetized. Large quantities of fluid containing trypanosomes were found post mortem in the pericardial sac and the thoracic cavity. The course of the infection with T. gambiense was mild, long lasting and did not appear to affect the chimpanzee unduly. The only noticeable change was an increase in the erythrocyte sedimentation rate. Trypanosomes were demonstrated in the cerebro-spinal fluid on two occasions. The development of primary chancres and the invasion of the central nervous system by T. rhodesiense and T. gambiense emphasize the potential role of the chimpanzee in experimental studies on African trypanosomiasis. It is also suggested that the extremely virulent nature of T. brucei in the chimpanzee may be a means of distinguishing this species from T. rhodesiense , but more evidence is needed concerning other strains, host variations and the effect of intercurrent disease.
TL;DR: A further factor that appears to be restraining any overall increase in malaria parasite rates, despite a recent rise in malaria risk, is the increased popularity of modern antimalarial drugs for the treatment of fever.
Abstract: Malarious communities in South Pare, in northern Tanzania, were protected during a 3-year experimental programme of residual insecticide spraying which ended early in 1959. On the conclusion of the spraying programme a simple treatment organization was set up to soften the clinical impact of the inevitable resurgence of malaria. The results obtained by this organization are briefly reviewed. In addition, regular malaria parasite surveys have been carried out in an attempt to follow the course of malaria transmission in South Pare since 1959. Although much of the area was very malarious in former times, the resumption of intense malaria transmission there has been unexpectedly delayed. This delay has been attributed largely to changes brought about in the original vector mosquito populations, changes originating during the residual spraying campaign but persisting well beyond the interval during which the mosquitoes were exposed to the direct activity of the residual insecticide. For instance, the once important local vector, A. funestus , had failed to re-establish itself completely in the area as recently as mid-1966; furthermore, it now seems probable that the South Pare A. gambiae underwent selection during the residual spraying campaign, resulting in the ascendancy of a relatively exophilic population of the species which lingered for several years after selection pressure was lifted. A further factor that appears to be restraining any overall increase in malaria parasite rates, despite a recent rise in malaria risk, is the increased popularity of modern antimalarial drugs for the treatment of fever. In addition, there is a general public awareness of the value of these remedies in coping with the current seasonal epidemic waves of malaria transmission. This report covers a period of 7 years since the final round of residual insecticide spraying. As the epidemiological situation in South Pare is not yet stable, it is considered that further regular surveys there should prove worth while.
TL;DR: The relationship between the state of maturity of the intra-molluscan phases of the larvae and subsequent success of the cercariae is discussed and the quantitative distribution of parasite eggs in the host tissues is described.
Abstract: Some of the characteristics of a strain of S. haematobium from South Arabia in experimental infections in hamsters are described. The relationship between the state of maturity of the intra-molluscan phases of the larvae and subsequent success of the cercariae is discussed. Growth curves for the adult worms and changes in uterine egg count with age are illustrated. The quantitative distribution of parasite eggs in the host tissues is described and approximate figures for the daily egg output of individual worms are given. The effects of host sex on worm burden and parasite sex ratio are discussed. The characteristics of this strain are compared with those of a strain from South Africa.
TL;DR: A relatively heavy (20 larvae) infection from a single mosquito was observed in one instance; however, in approximately one half of the mice exposed to mosquitoes harbouring infective larvae, no larvae were transmitted to the tissues of the mouse.
Abstract: A method is described whereby the fate of infective filarial larvae after feeding by vector mosquitoes may be estimated. In this investigation, Aedes togoi with a 77% rate of infection and an average of 7·5 infective Brugia pahangi larvae per mosquito, were permitted to feed on mice. The following observations were made: 1. 1. 22·3% of the expected number of infective larvae were transmitted to the tissues of mice. 2. 2. 32·3% of larvae remained in the mosquito. 3. 3. 45·4% of larvae were estimated to have been lost on the surface of the skin. 4. 4. A relatively heavy (20 larvae) infection from a single mosquito was observed in one instance; however, in approximately one half of the mice exposed to mosquitoes harbouring infective larvae, no larvae were transmitted to the tissues of the mice.
TL;DR: Electron micrograph morphology of the Leishman-Donovan body occurring in a nodular lesion of dermal leishmanoid has been described and the possible functional, cytochemical and morphogenetic implications of the structural pattern have been considered.
Abstract: Electron micrograph morphology of the Leishman-Donovan body occurring in a nodular lesion of dermal leishmanoid has been described. The size is similar to that of L. donovani as demonstrated by light microscopy. The leishmania shows a double-layered pellicle with a clear zone in between. A layer of subpellicular hollow fibrils numbering 80–120 is present. The nucleus has a double membrane with electron-dense material about 0·1μ thick on its inner aspect, and a karyosome. The distribution of this material corresponds to that of DNA as determined by the Feulgen reaction. The kinetoplast is seen as a series of electron-dense fibrils in a dilated area of a large mitochondrion; the fibrils correspond to the localization of Feulgen-positive kinetoplast in light microscopy. The rhizoplast is a complex structure with the usual 9 + 1 set of fibrils. It invaginates through a sac-like structure, the wall of which covers the fibrils and lines the vacuole around the fibrils. A funnel-shaped invagination of the pellicle extends to the neck of the rhizoplast, the distal end of which passes on to the surface of the parasite through the pit formed by the pellicular invagination. Other cytoplasmic structures have been described, viz ., the Golgi apparatus, the endoplasmic reticulum, the ribosomes, etc. The possible functional, cytochemical and morphogenetic implications of the structural pattern have been considered.
TL;DR: The “oasis scrub typhus” theory would explain the isolation of R. tsutsugamushi from Apodemus at Gupis, Gilgit Agency and the major elements of the flora and fauna are same as those in the Kaghan Valley.
Abstract: The presence of scrub typhus infection in rodents or trombiculid mites in the following unusual habitats and geographical areas in West Pakistan is discussed: (1) in alpine terrain at 10,500 ft. elevation in the Kaghan Valley of the Himalayas, where the snow remains on the ground 9 or 10 months of the year; (2) in the mountain deserts of Gilgit Agency, 36°N latitude; (3) in the semi-desert of Multan; and (4) in the plains of Lahore District. In these areas, unlike Sialkot District where Leptotrombidium ( Leptotrombidium ) deliense (Walch 1922) is abundant, known vectors of scrub typhus have not been collected, but related forms of the subgenus Leptotrombidium occur, and several of these are new to science. Natural infection with Rickettsia tsutsugamushi was demonstrated in almost all the habitats, virtually all from tissues of rodents. The highest rate of such positive isolations was from the temperate, coniferous forest zones of the Kaghan Valley (29 of 119, or 24%), primarily from indigenous mice, such as Apodemus, Alticola and Hyperacrius . Notes are included on the possible role in R. tsutsugamushi infection of the following rodents: Alticola roylei, Hyperacrius fertilis, H. wynnei, Millardia meltada, Nesokia indica and Tatera indica . Of the 3 strains recovered from the trombiculid mites (chiggers) 1 was from the endemic area at Sialkot; the others from chiggers from Alticola voles at 8,000 ft. in the Kaghan Valley. In the midst of the desolate mountain deserts of Gilgit occur “ecological islands” atop of peaks or in sheltered valleys watered by glacial streams, where the major elements of the flora and fauna are the same as those in the Kaghan Valley. Many of the species of small mammals and ectoparasites are probably relicts of aeons when the whole area was forested, and hence the infections associated with the fauna of the earlier period may also be present. The “oasis scrub typhus” theory would explain the isolation of R. tsutsugamushi from Apodemus at Gupis, Gilgit Agency.
TL;DR: Evidence is presented to show that the puncture wound made by the mosquito is the usual route of entrance and that this penetration of infective larvae takes place after the mouthparts of the mosquito have been withdrawn from the skin.
Abstract: Experiments were designed to determine the normal route of infection in mosquito-transmitted filariae. Evidence is presented to show that the puncture wound made by the mosquito is the usual route of entrance and that this penetration of infective larvae takes place after the mouthparts of the mosquito have been withdrawn from the skin.
TL;DR: Limited observations on infective mosquitoes probing several times in rapid succession for short periods, suggest that transmission and loss of larvae on the skin surface are very similar in mosquitoes feeding for a longer period.
Abstract: Observations were made on experimental transmission of infective Brugia pahangi larvae by Aedes togoi requiring varying periods of time for feeding and ingesting varying amounts of blood. Significantly more larvae were transmitted by mosquitoes which fed to repletion and required a longer feeding period than by those which failed to ingest any blood on short feeding attempts. This difference is attributed to the difference in probing time rather than lack of engorgement. No significant difference in transmission was found between mosquitoes which had fed to repletion and those which were partially engorged. Limited observations on infective mosquitoes probing several times in rapid succession for short periods, suggest that transmission and loss of larvae on the skin surface are very similar in mosquitoes feeding for a longer period.
TL;DR: It appears that the lower primates are less susceptible to infection with S. mansoni than the higher primates.
Abstract: After exposure to cercariae of Schistosoma mansoni it was found that a New World monkey (Saimiri sciurea—the squirrel monkey) was susceptible to infection, a prosimian primate (Nycticebus coucang—the slow loris) was relatively resistant, and a “pre-primate” (Tupaia glis—the tree shrew) was virtually insusceptible to infection. On the basis of this and other studies with primates, it appears that the lower primates are less susceptible to infection with S. mansoni than the higher primates.
TL;DR: Two patients with proved visceral leishmaniasis were studied with radio-iron 59Fe and radio-chromium 51Cr respectively, in an attempt to elucidate some of the mechanisms producing anaemia in this disease.
Abstract: Two patients with proved visceral leishmaniasis were studied with radio-iron 59Fe and radio-chromium 51Cr respectively, in an attempt to elucidate some of the mechanisms producing anaemia in this disease. The red cell life span was shown to be greatly reduced, with sequestration and probable haemolysis occurring in the spleen. The ferrokinetic studies suggested a mild degree of ineffective erythropoiesis. Blood volume determinations were normal.
TL;DR: In spite of continued blood loss, 3 patients with severe iron deficiency anaemia responded rapidly, clinically and haematogically, to oral iron treatment.
Abstract: The mean daily blood and iron losses in 7 patients with proved bilharzial colonic and rectal polypi were measured by the 51Cr-tagged red cell technique. The daily blood loss ranged from 7·5 to 25·9 ml. (mean 12·5 ml.) and the daily iron loss ranged from 0·6 to 6·7 mg. (mean 3·3 mg.). Surgical removal of a large polyp in one patient resulted in cessation of blood loss. In spite of continued blood loss, 3 patients with severe iron deficiency anaemia responded rapidly, clinically and haematogically, to oral iron treatment.
TL;DR: In many of the cases with severe haemorrhagic manifestations or shock, dengue virusAetiology could be established, and in some, chikungunya aetiology without any evidence of simultaneous denge infection could be shown.
Abstract: A new type of fever characterized by haemorrhagic manifestations or shock or both broke out in Calcutta as a double-peak epidemic in 1963. The epidemic was almost as severe in 1964 as in 1963, but in 1965 the morbidity was much less. 302 cases diagnosed clinically as haemorrhagic fever were virologically and serologically investigated during this period. 55% had arthralgia, 18% had skin rash, 14% had lymphadenitis and 28% had frank haemorrhage. Chikungunya virus, apparently a new one in India, was isolated from 64 patients and dengue virus (3 type 2, 2 type 4, and one probably type 1) from 6. In addition to those, a number of cases were diagnosed serologically as either chikungunya or Group B arbovirus (probably dengue) infection. In many of the cases with severe haemorrhagic manifestations or shock, dengue virus aetiology could be established, and in some, chikungunya aetiology without any evidence of simultaneous dengue infection could be shown. 10 of the 302 patients died. 18·8% of 439 human sera collected in 1964 and 32·3% of 537 sera collected in 1965 were positive against chikungunya antigen by the HI test. 14% of sera collected in Calcutta during 1960 were also positive by this test, indicating that chikungunya or a similar virus was present in the country before the outbreak of haemorrhagic fever in 1963. Chikungunya virus was isolated from 2 of 15 pools of Aedes aegypti (total 464). Laboratory-bred Aedes aegypti fed on acute chikungunya fever cases were found capable of transmitting the infection to infant mice.
TL;DR: A study of merozoite formation in the rodent malaria parasite Plasmodium vinckei, with both light and electron microscopes, has indicated that the cycle in the red cell has 3 successive phases.
Abstract: A study of merozoite formation in the rodent malaria parasite Plasmodium vinckei, with both light and electron microscopes, has indicated that the cycle in the red cell has 3 successive phases: 1. 1. Several nuclear divisions (usually 3), without cytoplasmic cleavage to produce a true “plasmodium” or syncytium with 8 nuclei. 2. 2. The formation of cytoplasmic protrusions by the plasmodium: each nucleus of the plasmodoum then migrates into one of these protrusions. 3. 3. The nucleated protrusions become detached as merozoites leaving a residual body in which pigment granules are segregated.