Showing papers in "Tropenmedizin und Parasitologie in 1982"

Epidemiological studies on the animal reservoir of Gambiense sleeping sickness. Part III. Characterization of trypanozoon stocks by isoenzymes and sensitivity to human serum.

Abstract: Polymorphism in 12 enzymes, as shown by electrophoresis on thin-layer starch-gel, was examined in 88 stocks of trypanosomes of the subgenus Trypanozoon isolated from man and animals in the Ivory Coast and Upper Volta Three of the enzyme profiles seen in trypanosomes from man in the Ivory Coast were exactly the same as in trypanosomes from local domestic pigs and from various game animals and a bovine in the Upper volta, thus confirming previous evidence that human trypanosomiasis is a zoonosis in West Africa Altogether 9 zymodemes were found in man; one was exactly the same as another from the Congo while a further one was identical to a Ugandan zymodeme Thirty-one zymodemes were found only in animals, and 6 were exactly the same as others from elsewhere in Africa, including the eastern part All zymodemes resembled each other by possessing common electrophoretic patterns in 5 enzymes In most zymodemes, the variants of two other enzymes were characteristically West African, although an East African influence was apparent, together with further evidence of hybridization Many zymodemes differed from others only to a minor extent in a few isoenzyme bands A group of closely related minor zymodemes constituted another trypanosome population ineffective to man in West Africa which had a variable sensitivity to normal human serum; enzymatically it was clearly separated from the major zymodeme previously described in West Africa, which was consistently resistant to normal human serum and had been previously associated with chronic gambiense sleeping sickness

Field studies of a reusable polyamide filter for detection of Schistosoma haematobium eggs by urine filtration.

Abstract: A reusable monofilament polyamide (Nytrel) filter and ninhydrin stained paper filter were compared in syringe filtration of urine to detect Schistosoma haematobium eggs in the urine under field conditions. The sensitivity of the technique using the Nytrel filter was similar to that of ninhydrin stained paper filters. The quantitative geometric mean S. haematobium egg counts obtained with the Nytrel filter were similar to those obtained with the paper filter.

Clinical, parasitological and serological studies on onchocerciasis in the Yemen Arab Republic.

Abstract: Dermatological symptoms of onchocerciasis and microfilaria densities in the skin were studied in 108 infected persons in the Governorate of Taizz, and the levels of antifilarial antibodies and IgA, IgE, IgG, and IgM were determined in 75 of them. Predominantly in old men the generalized form of the disease was observed, which is characterized by symmetrical, mostly atrophic skin lesions, rather high microfilaria densities at various sites of the body and the presence of diagnostically unequivocal levels of antifilarial antibodies. In younger men, children and women of various age groups a localized form was observed, of which the typical features are: an intensely itching, mostly asymmetrical, well circumscribed onchodermatitis with or without oedema, pachydermia and darkening of the skin; considerable enlargement of several local lymph nodes; very or extremely low microfilaria density; the microfilariae are mostly restricted to the area of the skin lesion; manifestation of the microfilariae by a clear papular Mazzotti reaction after the application of microfilaricidal drugs; and diagnostically utilizable levels of antifilarial antibodies. The localized form can develop into the generalized form during later years. Intermediate and so far undefined forms, among which indeterminate forms may exist, are also seen. Patients with severe localized onchocerciasis demonstrated significantly higher antifilarial antibody levels than other infected persons. As a characteristic feature of onchocerciasis in the Yemen, onchocercomata were frequently found over the muscles of the calf, thigh and forearm distant from prominent bones. Onchocerciasis is endemic in all major wadis with permanent, westward flowing streams at altitudes of 300-1200 m between the southern Wadi Ghail and Wadi Surdud in the north and in some of their tributaries.

Administration of praziquantel in neurocysticercosis

Abstract: Report of the observations of 40 patients suffering from neurocysticercosis, submitted to treatment by praziquantel, administered per os. Dexamethasone was associated to praziquantel in 20 patients. Side effects observed had a transient character. Transient exacerbation or reappearance of the cerebrospinal fluid neurocysticercosis syndrome, both related to the periods of treatment, can be considered an indirect rating of praziquantel action on cysticerci. This episode was observed in 31 patients. Dexamethasone proved sufficient to reduce the intensity of these episodes and of the effects. Evaluation of the 20 patients suffering from forms of the disease characterized by intracranial hypertension, and who had a follow-up of more than 3 months (up to 19 months) showed: disappearance of corticoid-dependence (5/5); disappearance of ventricular dilatation (4/6) appearance or increase inthe number of nodular calcifications (3/6); non-occurrence of new outbreaks of intracranial hypertension in 15 of the 20 cases. Repetitive characteristics of the clinical symptomatology, call for a longer-period observation of patients to allow for conclusion as to the effectiveness of the drug in the treatment of neurocysticercosis.

Vaccination of Jirds, Meriones unguiculatus, against Litomosoides carinii and Brugia pahangi using irradiate larvae of L. carinii.

Abstract: This study has shown tht exposure of jirds to radiation-attenuated larvae of one filarial species confers resistance to another species and thus indicates the potential for developing zooprophylactic regimens for the control of human filariasis. 13 and 8 Meriones unguiculatus were vaccinated with infective 3rd stage larvae of Litomosoides carinii attenuated by 40 krad Cobalt 60 irradiation and challenged with either L. carinii or Brugia pahangi respectively. Vaccinated jirds showed a 98% reduction in the expected challenge of L. carinii and a 71% reduction in the expected challenge of B. pahangi when compared to infectious in non-vaccinated controls.

Ultrastructural evidence for eosinophil-parasite adherence (EPA) reaction in human onchocercal lymphadenitis in the early period following diethylcarbamazine treatment.

Abstract: Specimens of lymph nodes from eight patients with onchocerciasis after treatment with diethylcarbamazine (DEC) were studied by electron microscopy. The sequence of events during the eosinophil-parasite adherence (EPA) reaction in human onchocercal lymphadenitis was similar to that in EPA reaction described in in vitro models. The majority of microfilariae showed severe degeneration. Eosinophils adhered to the microfilariae forming an exact template of their surface. Not seldom, the surface of microfilariae or part of it was covered with electron dense material containing several well preserved cores of eosinophil granules. Large vacuoles containing eosinophil granules developed also in vivo. Some vacuoles disclosed granules with preserved morphology, others revealed altered granules. In addition to the mature granules in the vacuoles also small type eosinophilic granules were observed. The intracytoplasmic granules showed a variety of morphologic alterations too (partial solubilization of granule content with preserved crystalloid; crystalloid material was dissolved within the matrix, etc.). Sometimes, around the granules tubulo-vesicular structures were observed. This study suggested that, in contrast to in vitro experiments, immunologically mediated necrosis of eosinophils with subsequent release of granules was the most important way of eosinophil-mediated cytotoxicity in vivo.

Trypanosoma brucei rhodesiense infection in vervet monkeys. II. Provocation of the encephalitic late phase by treatment of infected monkeys.

Abstract: Four out of 8 monkeys infected with Trypanosoma rhodesiense and treated with trypanocidal drugs at various intervals after infection (days 55-58, days 62-65, day 68) developed encephalitis. In 2 of these animals, killed 2 weeks after treatment, the encephalitis presenting was incipient; the other 2 monkeys died as a result of severe encephalitis a little more than 2 and 3 months after treatment, respectively. At the time of treatment, the animals revealed a parasitization of the CSF, but there were no clinical or neurological signs of any involvement of the central nervous system. The observations confirm observations made in human trypanosomiasis, and in experiments on rodents, which indicate that the encephalitic late phase may result from inadequate treatment. These observations may indicate that the encephalitis of the late phase may be methodologically provoked by infection and subliminal treatment after parasitization of the CSF, and that this procedure may be more promising of success than the method of infection only, as a method for the production of an animal model of the encephalitic late phase.

Light and electron microscopic studies on Schistosoma mansoni Granulomas of mouse livers following treatment with praziquantel.

Abstract: The disintegration of Schistosoma mansoni and their eggs was studied in the liver of mice after termination of the infection by praziquantel. Egg granulomas, which were already present at the time of treatment, attained their maximal diameter of 380 microns after 2-3 weeks. Within the following 5 weeks, granulomas very rapidly regressed in size to only 165 microns. Directly after treatment, worms were trapped in the liver where they were quickly invaded by granulocytes and subsequently phagocytosed within 3 weeks. Worm granulomas measured 700 and 900 microns after 3 and 8 weeks, respectively, but then regressed rapidly to only 550 microns after 12 weeks. Liver lesions appeared to regress more rapidly after praziquantel than after treatment with other schistosomicidal drugs.

Drug synergy in experimental African trypanosomiasis.

Abstract: The possibilities of trypanocidal drug synergy have been examined in vitro and in vivo using a monomorphic laboratory strain of Trypanosoma rhodesiense. Twenty-seven different drug pair combinations were chosen from among 12 representative trypanocides on the basis of surmized or reported synergy, evidence of collateral sensitivity in resistant strains, and known differences in modes of action or in field use. In vitro synergy test were made with a transfer plate technique which allows direct isobol determination by microtest tray superimposition. All pairs showing synergy in vitro were tested further in mice. Statistically significant synergy was shown only by suramin and tryparsamide, suramin and Puromycin, and suramin and Berenil. Although six other pairs, of which three contained suramin, showed higher than addictive cure rates, these rates fell short of statistical significance.

Large river treatment with Bacillus thuringiensis (H-14) for the control of Simulium damnosum s.l. in the Onchocerciasis Control Programme.

Abstract: Complete mortality of Simulium damnosum Theobald s.l. larvae was obtained along a 19 km stretch of the Marahoue River including and downstream of the Danangoro rapids complex in the Bandama Basin of Ivory Coast after treatment with 1.5 ppm/10 min of the Sandoz 402-1-WDC formulation of Bacillus thuringiensis Berliner serotype H-14. Partial control was observed for an additional 15 km. The level of control was especially encouraging considering the low concentration (.8%) of active ingredient in the Sandoz formulation. Additionally, the treated population has demonstrated resistance to temephos (Abate), the larvicide currently utilized in the Onchocerciasis Control Programme. Other species of Simulium were somewhat less affected by the treatment; living larvae were found 4 km downstream of the treatment point. Reinvasion of the Danangoro complex, ostensibly by drifting larvae of Simulium spp., was detected the day after treatment. Non-target organisms, including Ephemeroptera and Chironomid midges, were observed before and after treatment and were apparently not affected. In a second test, 0.8 ppm/10 min of the Sandoz formulation was tested, 0.8 pm/10 min of the Sandoz formulation was tested against S. damnosum s.l. and three other Simulium species in the N'Zi River in Ivory coast utilizing a gutter bioassay apparatus. Six hours after treatment 91% of the S. damnosum s.l. larvae had died. The other species responded with 91--100% mortality.

Trypanosoma brucei rhodesiense infection in vervet monkeys. I. Parasitologic, hematologic, immunologic and histologic results.

Abstract: Twenty vervet monkeys infected with T. rhodesiense (Eatro 1989) developed chronic disease with an average duration of 65 days (variation 35-107 days). With respect to the course of the disease, and to the hematologic, immunologic and histological findings, the disease faithfully mirrored human T. rhodesiense infection. In all animals, parasitization of the CSF occurred only a few weeks after infection, and was accompanied by an increase in the cell count and the appearance of IgM in the CSF. The main histopathological feature was severe pancarditis which was responsible for death in almost all animals. Chronic leptomeningitis resulted as histological substrate of the early parasitosis of the CSF. In most animals meningitis was accompanied by a mitigated encephalitic early reaction characterized by sparse lymphoplasmocytic infiltrates, exclusively of the cerebral vessels, with a predilection for the base of the brainstem and the neighbourhood of the ventricles. Autonomous meningoencephalitis with parasites in the brain tissue was found in only one animal (with the longest survival period of 107 days). In view of the regular parasitosis of the CSF, T. rhodesiense infection of the vervet monkey may be considered a suitable animal model for the assessment of the liquor "uptake" of trypanocidal drugs.

The identification of some Onchocerca spp of cattle by isoenzyme analysis.

Abstract: The isoenzyme patterns of LDH, MDH, PEP, PGM, MPI, GPI and GAPDH were compared for 3 species of cattle parasites Onchocerca gutturosa, O. gibsoni and O. lienalis from England, Australia and Mexico. LDH and GAPDH had identical patterns in each species but the other enzymes clearly distinguished between the species. PGM was the same in O. lienalis and O. gibsoni, but separated them from O. gutturosa. MPI and GPI had similar isoenzymes in O. gutturosa and O. gibsoni, but distinguished them from O. lienalis. Different isoenzyme patterns for all 3 species were obtained with MDH and PEP. The potential use of these techniques towards a better understanding of the epidemiology of human onchocerciasis is discussed.

The identification of two main-groups of Trypanosoma cruzi stocks from Brazil by their isoenzyme patterns of isoelectrofocusing.

Abstract: The isoelectrofocusing of seven enzymes was studied using extracts of 40 Brazilian stocks of T cruzi culture forms Four enzymes showed intraspecific variation in enzyme profiles and were selected for characterization of T cruzi These enzymes are: nonspecific esterase (EC311), phosphoglucomutase (EC 2751), glucose-6-phosphate dehydrogenase (EC 11149) and glucosephosphate isomerase (EC 5319) The parasite stocks were isolated from endemic areas in the States: Rio Grande do Sul, Sao Paulo, Espirito Santo, Minas Gerais and Bahia By combining the electrophoretic patterns of the four enzymes concerned the stocks have been classified into two main-groups Stocks of group I were exclusively isolated from wild animal reservoirs, whereas group II was mainly composed of stocks from human cases and domestic hosts Only three "sylvatic" stocks have been found in group II The enzymes glucose-6-phosphate dehydrogenase and glucosephosphate isomerase showed further subtypes within both groups I and II; their significance is not yet clear The results are in support of the existence of a domestic and a sylvatic transmission cycles in Brazil which are either clearly distinct or overlapping in some areas

The use of isoelectrofocusing in thin layer polyacrylamide and agarose gels as a method for the characterization of Venezuelan Trypanosoma cruzi stocks.

Abstract: The technique of isoelectrofocusing has been used to compare culture forms of 12 stocks of T. cruzi isolated in different regions of Venezuela. The following seven enzymes have been used for the characterization: unspecific esterase (E.C.3.1.1), malate dehydrogenase (E.C.1.1.1.37), "malic enzyme" (E.C.1.1.1.40), hexokinase (E.C.2.7.1.1), phosphoglucomutase (E.C.2.7.5.1), glucosephosphate isomerase (E.C.5.3.1.9) and glucose-6-phosphate dehydrogenase (E.C.1.1.1.49). The isoelectrofocusing method allows to determine reproducible enzyme patterns of high selectivity and with a number of bands. This permits to recognize possible differences within the T. cruzi-complex much easier than previous methods. The Venezuelan T. cruzi stocks showed a remarkable homogenous behaviour concerning the enzyme profiles. Most of them were identical. Different types seen for "malic enzyme", phosphoglucomutase, and glucose-6-phosphate dehydrogenase were observed in only three stocks, It was not possible to find a clear relationship between the types and the histories of stocks.

Differentiation between Trypanosoma cruzi and T. rangeli by their different complement sensitivity.

Abstract: Four-day-old culture forms of T. cruzi strains (Col-83, Y, OPS-31, OPS-32, PF, V, P-60), T. cruzi-like strains (WA-301, CL, FL, MR, Castro Alves, Tehuantepec, P), T. rangeli strain V and T. rangeli-like strain DA 3412 were tested with the following sera: mouse, NMRI-HAN, germ-free; rat, Wistar HAN, germ-free; guinea-pig, PBW:HAN, SPF; normal fresh guinea-pig, hen, rabbit and human sera, heat inactivated guinea-pig serum and normal fresh guinea-pig serum plus EDTA. Incubation of normal fresh guinea-pig, rabbit, rat and human sera lysed the epimastigote forms of T. cruzi and T. cruzi-like strains but not the culture forms of the T. rangeli and T. rangeli-like strains. Mouse serum did not lyse the culture forms of both trypanosome species while the hen serum lysed all culture forms of T. cruzi, T. cruzi-like as well as T. rangeli and T. rangeli-like. Using DEAE 52 cellulose it was possible to separate the metacyclic forms of T. cruzi and T. cruzi-like from the lysed epimastigote stages. A small number of epimastigote forms of T. cruzi and T. cruzi-like are lysis-resistant against normal fresh guinea-pig serum. Fresh normal guinea-pig, rat, rabbit and human sera can be used for the distinction between T. cruzi, T. cruzi-like and T. rangeli, T. rangeli-like.

Filariasis in Amerindians of western Guyana with observations on transmission of Mansonella ozzardi by a Simulium species of the amazonicum group.

Abstract: In order to conduct experimental infection studies of Mansonella ozzardi in local haematophagous Diptera, volunteers infected with this parasite were identified during a microfilaria survey in four Amerindian villages in the Pakaraima Mountains of western Guyana, near the Brazilian border. M. ozzardi microfilariae were detected in thick blood smears from 8-21% of persons examined. They were also found in skin snips from 8/73 persons all of whom were positive by blood smear examination. No Onchocerca volvulus microfilariae were detected. Dipetalonema perstans infections were found in three of the four villages but prevalence rates were only 1-8%. Manbaited catches of haematophagous Diptera made at the onset of the dry season in one of the villages yielded only three Simulium species. After flies were engorged on infected volunteers, M. ozzardi larvae developed to the infective stage in 6-7 days in the most abundant species, a member of the Simulium amazonicum group. Man-biting rates of up to 156 per 15-minute period were recorded for this species in midday collections along river banks near one of the villages. Developing filariae, including infective larvae of M. ozzardi, were also found in wild-caught flies. It was concluded that this Simulium species is a vector of M. ozzardi in the study area.

Anthropophily of Simulium damnosum s.l. and its rôle as a vector of human onchocerciasis in the Yemen Arab Republic.

Abstract: Immature stages of Simulium damnosum s.l. were collected in four of the main wadis (Surdud, Zabid, Rasyan, Ghayl) which drain westward to the Red Sea. The species was absent from the Wadi Tuban which flows to the south-east, but other black-fly species were found herein. For the first time it was shown that S. damnosum s.l. in the Yemen bites man, may ingest microfilariae of Onchocerca volvulus and can harbour filarial infections. Out of 303 flies which were caught on human bait in the Wadi Rasyan 33% were parous, four contained developing and three third-stage larvae (two of the flies had larvae in the head) indistinguishable from those of Onchocerca volvulus. The significance of these findings for the epidemiology of onchocerciasis and the possibility of vector control measures are discussed.

Human paragonimiasis caused by Paragonimus uterobilateralis in Liberia and Guinea, West Africa.

Abstract: In the children from Liberia and one woman from Guinea an infection with the lung fluke Paragonimus uterobilateralis was diagnosed, being the first cases of human paragonimiasis recorded in these two West African countries. Species determination was based on measurements and morphological structure of the parasite ova isolated from sputum and stool of the patients, and supported by biological and epidemiological evidence of the occurrence of this parasite species in natural animal hosts and P. uterobilateralis--metacercariae in freshwater crab populations in various parts of Liberia.

L'utilisation des écrans dans la lutte anti-tsétsé en zone forestière

Abstract: After preliminary studies on the ecodistribution of Glossina palpalis s.l. in the sleeping sickness focus of Vavoua (Ivory Coast) trials with screens impregnated with decamethrine were carried out. Artificial supports for insecticide present several advantages: less pollution, less costly, simplicity, facility of use by local personnel, possibility of re-use, integration with other methods. On the other hand, its action based on the attraction of flies which come into contact with the screen is relatively slow, particularly in obtaining a complete interruption of reproduction. The technique is compared with other control methods as the use of biconical traps and selective spraying along borders. Its action can be improved by the addition of attractive host odours or sex pheromones.

A diffusion chamber technique for detecting compounds with clinical prophylactic activity against Brugia pahangi.

Abstract: A new technique for examining the clinical prophylactic activity of antifilarial agents against Brugia pahangi is described. Third stage larvae were confined within diffusion chambers before intraperitoneal implantation into jirds. Such larvae developed normally within the chambers for 14 days when compared with infections in which larvae were allowed to grow freely within the peritoneal cavity. After this time conditions inside the chambers deteriorated and larval growth was inhibited. Larval recoveries from diffusion chambers after 14 days were higher and more reproducible than from intraperitoneal infections. The activities of known antifilarial agents against larvae confined within chambers implanted into jirds were examined. The benzimidazoles were found to be extremely effective Flubendazole killed almost all larvae when administered at 5 x 25 mg/kg sc by day 9 after the final treatment. It is suggested that the test described has potential as a screen for detecting clinical prophylactic activity because of its reproducibility, low parasite requirement, ease of parasite recovery and relatively short result acquisition time.

In vitro phagocytic activity of neutrophils of various cattle breeds with and without Trypanosoma congolense infection.

Abstract: A simple in vitro-technique using latex beads was used for the investigation of the phagocytic activity of neutrophils in bovines of different breeds, infected and non-infected with T. congolense. It was found that the N'Dama, assumed to be trypanotolerant, have a significantly higher number of neutrophils and neutrophils with phagocytic activity per mm3 blood, compared to the more susceptible Zebu, the Baoule and the crossbreed M75, ranging between these two breeds. The first appearance of T. congolense in the blood was accompanied by a significant increase of phagocytizing neutrophils in 21 bulls of different breeds and 12 N'Dama cows in comparison to the pre-infection levels or to the animals which remained free of trypanosomes. A possible involvement of the neutrophils in the defence against trypanosomes by phagocytosis is discussed.

Antigen sharing between Fasciola hepatica and human erythrocytes.

Abstract: Several lyophilized bovine and ovine liver flukes (Fasciola hepatica) extracts were examined for the presence of blood group like antigens using an automated haemagglutination inhibition procedure. This sensitive method allowed the detection of A, B, H. Lea, Leb, P1, and Pk group specific substances. Their immunogenicity was confirmed in anti-Fasciola hyperimmunized rabbits. Immunofluorescent probes showed that these substances are located on cell membranes of the tegumental syncytium and caeca epithelium cells of the fluke. These data were discussed along with current concepts concerning, the origin, the consequences ant the biological significance of the occurrence of blood group like substances in parasites.

The fine structure of adult Onchocerca volvulus. I. The cuticle, the hypodermis and the muscle cell of the male worm.

Abstract: The fine structure of the cuticle, the hypodermis and the muscle cells of five male worms from Liberia and of two male worms, at least five years old, from Upper Volta is described. The cuticle in the lateral regions is thicker and consists of more layers than in the dorsal and ventral regions. The innermost zone of the hypodermis contains a wide labyrinth of extracellular clefts. The muscle cells are of the shallow coelomyarian type. Bacteria were found in the hypodermis of worms from Liberia and Upper Volta. The hypodermis and the muscle cells contained various other inclusions and particles. Some of them were formed by aggregations of regularly arranged membranes and lamellae. Although all the worms had been alive at the moment of fixation, severe degenerative alterations of the hypodermis and the muscle cells could be observed. Only the cuticular morphology was more or less constant in all seven worms.

Single dose treatment with praziquantel (Cesol R, EmBay 8440) of human cestodiasis caused by Diphyllobothrium pacificum.

Abstract: Diphyllobothrium pacificum, a large tapeworm of seals, is often found as an accidental parasite of man in Peru. The main symptoms is causes are abdominal pain, meteorismus and flatulence, and diarrhea. We report the results of 32 single-dose (10 mg/kg weight) treatments with Praziquantel (Cesol R, EmBay 8440) in 31 patients. One of these patients was shown to be cured but presented a reinfection 270 days later, and required retreatment. Praziquantel was effective in all cases. All patients were clinically cured. No ova were found in stool examinations at 30, 60, and 90 days after treatment, while pretreatment stools were positive for ova with all the techniques used. The antiparasitic effect was evident in 11 cases which segments of the tapeworm were eliminated within the first 3 days of treatment: the fragments were all partially digested or autolysed. A treatment scheme incorporating a purge may be best, to recover the parasite in its entirety and thus ascertain cure with no repeated controls.

Scanning electron microscope study of adult Brugia malayi.

Abstract: The fine structures of the surface of Brugia malayi obtained from Mastomys natalensis are demonstrated by scanning electron microscopy. The head of the parasite is bulbous in shape. The amphidial openings lie beside small elevations. The surface structure of the inner papillae is smooth with a small elevation in the middle. The outer papillae are grooved. the cuticular annulation in the midbody region of the female worm is narrower than that of the male cuticle. In the posterior region of the female worm there are tubercles and in one worm a lateral papilla was found near the anus. In both sexes the inconspicuous phasmidial openings are situated in a lateral position close to the caudal tip. In the posterior region of the male worm there is an area with tubercles, the area rugosa and numerous perianal and caudal papillae, which vary in their number and distribution. The surface structures are very similar to those of Brugia pahangi.

Effects of some African game animal sera on Trypanosoma brucei rhodesiense and T.b. brucei clones.

Abstract: The effects of different African game sera on Trypanosoma brucei rhodesiense and T.b. brucei clones have been studied in vitro and in vivo, for the first time, using a modified version of the blood incubation infectivity test (BIIT). Trypanosomes were incubated in vitro with serum samples from a number of different game animal species and their subsequent infectivity for proven susceptible rats then examined after one hour and 8 hours of serum incubation. Sera from eland, waterbuck and, to a lesser extent, spotted hyaena and hippopotamus, were trypanolytic in vitro and destroyed normal infectivity of the trypanosomes to laboratory rodents. Fluorescent antibody testing showed that some of the game sera had highly antibody titres to T. brucei antigen.

Curative effect of alpha-difluoromethylornithine on fatal Trypanosoma congolense infection in mice.

Abstract: The curative effect of alpha-difluoromethylornithine (DFMO) on fatal T. congolense infection in mice was investigated using various concentrations administered orally in drinking water. Permanent cure was achieved in mice receiving 4% for 3 days or 2% for 5 days. Mice receiving less became parasitemic again but then, without any further treatment, resisted death due to trypanosomes for an average of 34.5 days, while untreated controls were dead within 8 days after trypanosomes were first seen in their blood.

A new simple technique for rearing F1 progeny from females of the Simulium damnosum Theobald complex.

Abstract: Laboratory rearing of Simulium damnosum complex species enables female adults to be indirectly identified from their larval progeny. A simple, readily transportable rearing apparatus was developed for investigations by the Onchocerciasis Control programme by using unbreakable, easily packed and reassembled parts and by feeding the larvae at least partly with living green algae (Chlorophyceae) cultured in the laboratory. Although the larvae are sensitive to excess nitrogen compounds, the use of algae and a large volume of water obviated the need for a separate purification system in which water was circulated by an A/C electrical centrifugal pump between a container and an inclined trough in which most of the larvae developed. The rate of development was rapid giving rise to full size larvae (suitable for cytotaxonomic determination), pupae and adults. The adults were attracted into a collecting device by light. Developments to protect the larvae during electrical power failures included a slow-drying wooden rearing trough and an automatic switch to an alternative D/C power supply and pump. This technique has been in general use in O.C.P. laboratories in Benin, Ghana, Ivory Coast and Upper Volta and many thousands of larvae have been reared.

Serodiagnosis of opisthorchis viverrini infestation by an enzyme immuno-assay.

Abstract: The application of an enzyme immuno-assay is evaluated with regard to antibody reactivity to Opisthorchis viverrini antigen in 20 Laotian patients and control groups including patients with other helminthic infections as well as persons without parasitic infestation. It is concluded that the enzyme immuno-assay indicates infection by O. viverrini. In certain circumstances, which are discussed, the test may serve for valuation of treatment.

The response of Bos taurus and Bos indicus cattle types to inoculation of lymphoblastoid cell lines infected with Theileria parva schizonts.

Abstract: In a preliminary experiment eight Bos indicus type cattle were inoculated with 10(9) cells of a Bos taurus lymphoblastoid cell line infected with Theileria parva schizonts. Four cattle showed patent infections and one died of theileriosis. On challenge of the surviving cattle with a tick derived stabilate of the same stock of T. parva no animal died of theileriosis. To test the susceptibility of Bos taurus and Bos indicus cattle to cell lines of both cattle types infected with T. parva of the same stock, 10(9) cells of each cattle type were inoculated into five cattle of each type. Bos taurus cattle had a higher susceptibility to infection regardless of the origin of the donor cells. Two Bos taurus type cattle receiving Bos taurus cells died of theileriosis while none receiving Bos indicus cattle died. Both cattle types were more susceptible to infection with cells derived from their own cattle type. All surviving Bos indicus and Bos taurus cattle were immune to lethal stabilate challenge. The possibility that the histocompatibility type of the donor cells influences the success of the immunization is discussed.