Showing papers in "Annals of Tropical Medicine and Parasitology in 1989"

The chemotherapy of rodent malaria. XLIV. Studies on the mode of action of CM 6606, an indolo (3,2-c) quinoline N-oxide.

Abstract: CM 6606 differs in its mode of action from chloroquine but studies on its activity against parasites resistant to other antimalarials suggest that it may have some features in common with aminoalcohols. Similarities in drug-induced pigment changes are especially striking. Only halofantrine shows a reduced activity, however, against parasites that are highly resistant to CM 6606, while such parasites are slightly hypersensitive to sulfadoxine and clindamycin. Evidence suggesting that CM 6606 may function through an active metabolite, possibly CM 6609 in which the N-oxide is reduced, is discussed.

Thiabendazole vs. albendazole in treatment of toxocariasis: a clinical trial.

Abstract: Between 1986 and 1988, 34 patients (age range six to 83 years) with visceral or ocular larva migrans were randomly assigned to a five-day treatment with thiabendazole 2 x 25 mg kg-1 day-1 (15 patients) or albendazole 2 x 5 mg kg-1 day-1 (19 patients). On the fifth treatment day, six patients (40%) in the thiabendazole group and 11 patients (58%) in the albendazole group showed excellent or good drug tolerability. Efficacy of treatment was assessed after 30 weeks (range six to 56 weeks). In the thiabendazole group, median eosinophilia remained at 14% and four patients (27%) were clinically cured. In the albendazole group, the median eosinophilia decreased from 10 to 3.5% and six patients (32%) were clinically cured. We recommend albendazole for treatment of visceral and ocular larva migrans with a minimum dose of 10 mg kg-1 daily for five days.

Capture-recapture studies with the South American malaria vector Anopheles darlingi, Root.

Abstract: A capture-recapture experiment was undertaken in October 1987, in the Jaru district of Rondonia, Brazil, with the malaria vector Anopheles darlingi. On two consecutive nights, 160 blood-fed, 78 unfed biting and 81 unfed resting mosquitoes were released. Recapture rates of 12–19% and survival rates of 0·59–0·57 per oviposition cycle were obtained for all releases, indicating that blood-feeding was not an obstacle for this population, which had a high vectorial capacity. Two A. darlingi were collected 7·2 km from the release site nine days after release. In contrast, recapture rates for 259 anophelines of nine other species released were only 2·3%. These other species also had a limited flight time and range in comparison with A. darlingi, which indicates that the latter is the only malaria vector of importance in this part of Brazil.

The aetiology of severe anaemia in pregnancy in Ndola, Zambia

Abstract: The aetiology of severe anaemia (haemoglobin less than 7.0 g dl-1) has been studied in 37 pregnant Zambians. Aetiology was usually multiple; 31 (84%) had Plasmodium falciparum malaria, 23 (62%) were folate deficient, 13 (35%) were iron deficient, one had sickle-cell anaemia and one had the acquired immunodeficiency syndrome (AIDS). Folate deficiency was most often secondary to malarial haemolysis: iron deficiency was nutritional, but hookworm was contributory in about one-third of patients. The anaemia of malaria and folate deficiency was both more common and more severe than anaemia due to iron deficiency; it was seen in younger women although primigravidae were not over-represented, it occurred earlier in pregnancy, and was associated with low birthweight. AIDS must now be included in the differential diagnosis of anaemia in pregnancy. Vigorous antimalarial treatment and prophylaxis are essential in the management and prevention of anaemia in pregnancy. Total dose iron infusion is indicated only when severe iron deficiency anaemia has been proven, and must be accompanied by antimalarial therapy and folic acid supplements. Because of the risk of transmission of human immunodeficiency virus, it is more important than ever to prevent anaemia and malaria in pregnancy, and to give blood transfusion only as a life-saving treatment.

Biological control of Biomphalaria glabrata and B. straminea by the competitor snail Thiara tuberculata in a transmission site of schistosomiasis in Martinique, French West Indies

Abstract: In Martinique, intestinal schistosomiasis was discovered at the beginning of this century. The intermediate host snail, Biomphalaria glabrata, was considered in the past as a common species in the different habitats of the island, but during the last decade it has been found only in water-cress beds. Several of these water-cress cultures contained mixed populations of B. glabrata and B. straminea. Moreover, these habitats also constituted transmission sites for Schistosoma mansoni infection. In 1979 the thiarid snail Thiara ( = Melanoides) tuberculata was discovered in Madame river, Fort-de-France, and in the following years at other sites. In 1983 a programme of biological control using this snail was started in two groups of water-cress beds. In 1981-1982 the study site, Roxelane valley, sheltered important populations of B. glabrata (45-256 individuals/m2) and of B. straminea (2-30 ind./m2). In January 1983 the competitor T. tuberculata was introduced into the two groups of water-cress beds (1.3 and 1.7 ind./m2 respectively) and during subsequent years snail population sampling was carried out. The results showed rapid colonization by the competitor snail, whose densities reached 178 and 325 ind./m2 in November 1983 and a maximum of 9941 and 13,388 ind./m2 in October 1984. During that time, B. glabrata populations declined: 153 and 41 ind./m2 in November 1983, 4 and 0 ind./m2 in October 1984, and 0 ind./m2 in the two groups of water-cress beds in October 1985. A similar phenomenon was observed for B. straminea. Since October 1985 neither planorbid species has been found by exhaustive sampling of the habitats.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemotherapeutic effects of Annona senegalensis in Trypanosoma brucei brucei.

Abstract: Mice infected with Trypanosoma brucei brucei 8/18 strain were treated orally and intramuscularly (im) with aqueous root extracts of Annona senegalensis, in doses of 27.8 mg kg-1 and 9.5 mg kg-1 respectively, for four consecutive days commencing 72 hours after the mice were infected. At these dosages the parasites were cleared from the circulation and no relapse was recorded over 60 days. The plant extract, however, had no effect on the trypanosomes when therapy was initiated at the late stages of infection, that is, about the sixth day when the parasitaemia level was 0.9 x 10(6); and all the animals died a day or two later. The herbal extracts also did not show any prophylactic action when given prior to infection. The root extract possesses different margins of safety in the mice depending on the route of administration. The therapeutic index for oral administration was 5.13, and that for im administration was 1.8. Chemical tests revealed that the plant extract contains alkaloids, saponins and tannins. Adverse reactions, especially to doses of 2.3-5.76 mg kg-1, were noted in animals that received the drug parenterally, but not when the drug was administered orally. However, A. senegalensis is shown to be therapeutically effective against T. b. brucei in mice, which agrees with the claims of Nigerian practitioners of Traditional Medicine that it is effective against trypanosomiasis in man.

Soil particles in the tissues of the foot in endemic elephantiasis of the lower legs.

Abstract: The presence of microparticles of clay is demonstrated in the dermis of the foot in a patient with, endemic elephantiasis. The particles are seen to be in the phagosomes of macrophages or in the cy...

Parasite/host-interrelationships of the trypanosomatids Trypanosoma cruzi and Blastocrithidia triatomae and the reduviid bug Triatoma infestans: influence of starvation of the bug

Abstract: We have investigated the effects of Trypanosoma cruzi and Blastocrithidia triatomae on the life span of starved second/third (L2/3), third/fourth (L3/4), and fourth/fifth instars (L4/5) of Triatoma infestans, which had been infected in the first instar and fed last in the second, third or fourth instar respectively. The intestines and sometimes also the flagellate populations of dead bugs were examined. In uninfected L2/3 a higher relative humidity prolonged the life span. With a maximal survival of 14 months, uninfected L3/4 were the most resistant to starvation, followed by L4/5 and then L2/3. Trypanosoma cruzi reduced the life span of starved L3/4 and L4/5 by only 14% and 17%, respectively. Infection with B. triatomae reduced life spans by 51% (L2/3), 55% (L3/4) and 32% (L4/5). The intestines of dead infected bugs were more likely to contain incompletely-digested blood remnants than those of uninfected bugs; living flagellates occurred in all parts of the intestine, and often the rectal lumen contained more dead flagellates than were found on the rectal wall.

Epidemiological studies on toxocariasis and visceral larva migrans in a zone of Western Spain

Abstract: An epidemiological study on toxocariasis was carried out in a zone of Western Spain (province of Salamanca) in dogs, soil and humans, comparing the simultaneous situations in urban and rural areas. The prevalence of infection in dogs was 29.4 to 33.1%, with little difference between the areas studied. The prevalence of Toxocara eggs in soil ranged from 3.7% in Salamanca city to 9% in rural areas. Seroprevalence in humans, as shown by Dot ELISA, was higher in children (8.5% in urban areas and 4.6% in rural areas) than in adults. The statistical significance of the correlations between prevalence and the different factors that affect transmission of the parasite was studied, and its importance at local level is discussed.

A single trypanosome is sufficient to infect a tsetse fly.

Abstract: Pour determiner si un trypanosome unique peut infecter une mouche tse-tse, on presente aux mouches une nourriture infectee et diluee de telle facon qu'a la dilution finale, il y ait seulement une petite chance que la mouche prenne un seul trypanosome. 21 jours plus tard, dissection et analyse de l'intestin et de l'hypopharynx

The effect of schistosome infection on the mortality rates of Bulinus globosus and Biomphalaria pfeifferi.

Abstract: Schistosoma infections of Bulinus globosus increased the per capita mortality rate in the laboratory from 0·231 to 0·406 per week.Schistosoma mansoni infections of Biomphalaria pfeifferi increased ...

The effects of 5,6 benzo-[a]-pyrone (coumarin) and DEC on filaritic lymphoedema and elephantiasis in India. Preliminary results.

Abstract: A randomized double-blind, placebo-controlled, trial of 5,6 benzo-[alpha]-pyrone (coumarin, '56 BaP') and of diethylcarbamazine (DEC) is being performed on patients with filaritic lymphoedema and elephantiasis over two years, using matched groups. In 169 patients there were significant (1% level) reductions in the amounts of oedema for the patients taking 56 BaP. The excess limb volumes were reduced from 40 to 25% over two years. A similar, but less significant (5% level), improvement was found for the circumference measurements. The rate of reduction was increased when the initial amount of oedema was greater. This therapy, while much slower than many other methods of treatment, does convert a slowly worsening condition into a slowly improving one. There were no significant reductions in the amount of oedema following DEC treatment.

Effect of praziquantel on the eggs of Schistosoma mansoni, with a note on the implications for managing central nervous system schistosomiasis.

Abstract: The morphology of Schistosoma mansoni eggs in intestinal tissues (oograms), and egg hatching in faeces, were studied after parenteral administration of praziquantel (PZQ) to infected mice. PZQ was ...

Canine filariasis in Salamanca (northwest Spain).

Abstract: A survey of dogs in four areas of Salamanca province (northwest Spain) was carried out to determine the prevalence of filariids in the canine population Blood samples from 293 dogs were tested for

Observations on human echinococcosis (hydatidosis) and evaluation of transmission factors in the Maasai of northern Tanzania.

Abstract: An attempt was made to estimate the prevalence of hydatid disease amongst the Maasai people of northern Tanzania and to examine the factors which would contribute to the transmission of the disease...

Treatment of arsenical refractory Rhodesian sleeping sickness in Kenya.

Abstract: Case histories of three Rhodesian sleeping sickness patients who relapsed after Mel-B therapy are presented. Repeated Mel-B therapy was clinically effective but not curative, and all three patients subsequently relapsed again and required further treatment.

A serological test for the diagnosis of Strongyloides antibodies in ex Far East Prisoners of War.

Abstract: This paper gives the results of an ELISA test for Strongyloides stercoralis antibodies in a group of 436 ex Far East Prisoners of War (FEPOWs). Antigen was obtained from third-stage larvae of Stron...

Experimental studies of Korea Taenia (Cheju strain) infection in domestic animals.

Abstract: In the present study, one DYL pig (five-day old), four L-SEM pigs (37-day old), three SEM pigs (44-day old), one Holstein calf (eight-day old) and two Sannean goats (five-day old) were each fed 1000, 30,000, or 380,000 eggs of the Korea Taenia (Cheju strain) and were sacrificed 16-105 days after inoculation. All DYL, L-SEM, and SEM pigs and the Holstein calf were susceptible to Korea Taenia, and one of the two Sannean goats became infected. The cysticerci recovery rates for L-SEM, SEM and DYL pigs, Holstein calf, and Sannean goat were 5.6, 1.7, 0.06, 0.03 and 0.02% respectively. Cysticerci were recovered only from the livers of the infected animals, and more cysticerci were found in the parenchyma (51%) than on the surface of the liver (49%). Immature cysticerci were first observed on day 16 after infection, mature ones on day 29, and degenerated or calcified cysticerci on day 30. Inoculation of a huge number (380,000) of Korea Taenia eggs lead to early degeneration or calcification of the cysticerci. The length, the width, and the diameters of protoscolex, rostellum, and sucker of the cysticerci were largely proportional to the period of inoculation. The measurements and patterns of the hooklets indicate that Korea Taenia is very similar to Taiwan Taenia but is different from T. saginata and T. solium. The results of the present study provide evidence that Korea Taenia and Taiwan Taenia may be of the same species.

Disability from dracunculiasis: effect on mobility.

Abstract: A study was conducted in northeastern Imo State to define the disability and restriction of mobility associated with dracunculiasis. The study was part of an evaluation of the UNICEF-assisted Drinking Water Supply and Sanitation Project in Imo State, Nigeria. A sample of household units (100 in year 1, 195 in year 2) was visited every two weeks to determine who was affected by dracunculiasis and to characterize the extent of related disability. The average duration of symptoms was 12.7 weeks (range 3-29 weeks). Fifty eight per cent of all episodes of disease resulted in severe disability (with the individual unable to leave the compound) lasting a mean of 4.2 weeks (range 2-12). The mean period of severe disability was significantly higher for those aged 50 years and over than for those less than 50 years old. In the area studied, the disease occurred during the peak yam and rice harvest time and the period of preparation for the planting season. This is the first study to document systematically and prospectively the marked restriction of normal activity in affected individuals and the long duration of the disability. These findings can assist in improving estimates of the costs associated with dracunculiasis and of potential economic benefits if the disease were eradicated.

Effect of albendazole in experimental toxocariasis of mice.

Abstract: Fifty-five mice were each infected with 800 embryonated eggs of Toxocara canis. Beginning on the second day of the infection, one group received a single 9 mg dose of albendazole every 24 hours for an eight-day period while a second group received 3 mg of albendazole every eight hours for the same period. On the tenth day of infection, mice in each treatment group and their corresponding controls were sacrificed, and the presence and motility of T. canis larvae in the brain were determined. With both therapeutical procedures the administration of albendazole reduced the number of larvae which reach the brain. However, for the same total dose, the administration of the drug every eight hours yielded results which were significantly superior to those produced by administering a single dose every 24 hours, reducing both the number of larvae in the brain and their motility.

Congenital kala-azar.

Abstract: An 11-month-old male infant was admitted to hospital with fever, pallor and hepatosplenomegaly, and was diagnosed as having kala-azar. The mother also suffered from kala-azar while carrying this baby. As the baby and the mother did not leave Delhi either during or after delivery, and the vector found in Delhi is not competent to transmit leishmaniasis, the infant could not have been infected by the bite of a sandfly. It therefore seems most likely that he was infected in utero--a rare route.

Eosinophilia as a marker for chronic strongyloidiasis--use of a serum ELISA test to detect asymptomatic cases.

Abstract: In a previously published survey of 602 former Far East prisoners of the 2nd World War (FEPOWs), 88 (15%) were found to have Strongyloides stercoralis infections. A further 25 (4·2%) had significan...

Experimental infection of cattle with Trypanosoma brucei rhodesiense.

Abstract: Infection of cattle with various stocks of Trypanosoma brucei rhodesiense indicated that 49% developed a fatal CNS disease comparable to that found in man. Duration of disease ranged from 85 to 1613 days post infection. All eight stocks of T. b. rhodesiense tested, including those from Ethiopia and Tanzania, induced CNS disease. Blood became positive three to five days after inoculation, and after an initial peak of parasitaemia remained positive for three to five months. Subinoculation of blood into rodents subsequently became negative, although trypanosomes persisted in the lymph nodes for at least 56 to 1613 days. Only animals with CNS disease had detectable parasites in the CSF, usually after the animals had undergone severe deterioration. At post mortem examination trypanosomes could usually be found in the lymph nodes and CSF, and occasionally in the blood. Clinical signs included fever, hyperkinesia, weight loss, cerebellar ataxia, tremor, salivation and hyperaesthesia. A mild to moderate anaemia accompanied a transient thrombocytopenia and leucopenia. Animals subsequently developed leucocytosis. A pleocytosis and elevated total protein in the CSF was found, which persisted in some animals for long periods. Histopathological examination of the brain showed prominent generalized perivascular infiltrates consisting mainly of lymphocytes and plasma cells. Mott's cells were regularly observed. Vascular changes were characterized by swollen endothelium, infiltration of the vascular wall by inflammatory cells, and in some instances perivascular oedema. In the most severe cases evidence of ischaemia consisted of large numbers of astrocytes, rarefaction of the parenchyma, and areas of necrosis with loss of normal architecture. Demyelination was limited to perivascular areas. Occasionally a moderate to severe pancarditis was found.

The aetiology of chronic renal failure in adult Sudanese patients.

Abstract: One hundred adult Sudanese patients who presented to Soba University Hospital (SUH) with established chronic renal failure (CRF) were studied to determine the aetiology. Thirty-eight had chronic glomerulonephritis, 12 renal calculi, nine diabetic renal disease, seven chronic pyelonephritis, five sequelae of acute renal failure (ARF), four renal vascular disease, three polycystic disease of the kidneys, and two obstructive uropathy. In 20 patients the aetiology was not determined because of late presentation to hospital. The results were compared with those of the developed countries, which differ greatly from Sudan in climate, diet, race, culture and social habits. The main differences were in the prevalence of renal calculi which, although being the second commonest cause of CRF in the Sudan, were rare in European countries. Also, diabetes mellitus was a much commoner cause of CRF in Sudan than Europe. Other aetiological factors were similar.

Measuring morbidity from malaria

Abstract: (1989). Measuring morbidity from malaria. Annals of Tropical Medicine & Parasitology: Vol. 83, No. 3, pp. 321-323.

Prevalence of Toxocara ova in some schools and public grounds in northern and central Jordan.

Abstract: Two hundred and twenty-six soil samples were collected from school playgrounds and public places in four cities and 17 villages in northern and central Jordan. Toxacara eggs were found in 35 (15.45%) of the samples. Viable eggs were found in 18 samples, with viability ranging from 20 to 78%, and among these 18 samples the mean number of viable eggs per 5 g soil was 5.5 +/- 4.58 S.D. (range one to 15 eggs). Nine of 94 samples collected from public places and five of 86 samples collected from schools contained Toxocara eggs. Viable eggs were found in higher proportions of soils collected from villages around Jerash (three of 21) and Irbid (five of 44), and from Yarmouk University campus (four of 37), than of soils collected from cities (six of 124), but the differences are not significant (P less than 0.05). Eggs of Taenia spp., Hymenolepis diminuta and Ascaris lumbricoides were also recovered, in 34, 15 and nine samples respectively of the 226 examined.

The host preferences of Chrysops silacea and C. dimidiata (Diptera: Tabanidae) in an endemic area of Loa loa in the Congo.

Abstract: The analysis of 404 blood meals from Chrysops silacea and C. dimidiata which had been collected in the forests of the Chaillu mountains (People's Republic of the Congo) has demonstrated for the fir...

Mortality in a rural area of Madang Province, Papua New Guinea.

Abstract: As part of a multi-disciplinary research programme undertaken by the Papua New Guinea Institute of Medical Research near the town of Madang, northern PNG, a three-year study of mortality was conducted in a rural population of approximately 16,500 people. From early 1982 the area was under continuous demographic surveillance which continued for the three years of the study. All deaths which occurred in this period were investigated by interviewing relatives of the deceased and examining any available health service records. Respiratory diseases were the commonest cause of death, with pneumonia accounting for 20% of deaths in children under 10 years of age, and pneumonia and chronic obstructive lung disease (COLD) together accounting for a third of all deaths. Deaths from COLD were more common in the study population than in PNG hospitals and health centres. The proportion of deaths caused by malaria in children under 10 years was estimated to be between 4 and 17%. Mortality rate in the first year of life were determined by following up a cohort of 1015 births occurring in the first 20 months of the study. Of the 1002 live births, 46 died in the first 12 months of life, giving an infant mortality rate of 45.9% live births. Other mortality and demographic rates were consistent with data reported from the 1980 PNG National Census, suggesting that the study population belonged to an advantaged rural area. Demographic features found in this population were a high birth rate, a relatively low crude death rate, and a rate of natural population increase of 2.8% per annum. The methodological difficulties associated with the measurement of malaria mortality have important implications for the evaluation of future malaria vaccines. The methods employed in this study are critically discussed, and recommendations made for future studies.

Presenting features of Rhodesian sleeping sickness patients in the Lambwe Valley, Kenya.

Abstract: During a recent outbreak of Rhodesian sleeping sickness in the Lambwe Valley no asymptomatic Rhodesian sleeping sickness patients were found although 54% of the primary patients had mild symptoms and 9% were stuporous or comatose at presentation. The duration of symptoms was three months or less in 90% of the patients. Headache, weakness, joint and back pains and weight loss were claimed by at least 75% of the patients, while 82% of the females reported amenorrhoea and 70% of the males claimed impotency. Physical examination revealed lymphadenopathy in 86% but fever in only 36% of the patients, while chancres were found in only 16%. Patients had significantly lower levels of haemoglobin and thrombocytes than controls and their erythrocyte sedimentation rates were elevated. A comparison of both blood group and haemoglobin type between patients and controls yielded no significant differences. Fifty-seven per cent of the primary patients reporting mild symptoms had abnormal levels of leucocytes in their CSF. All relapse patients had abnormal CSF parameters. Levels of serum urea nitrogen were significantly elevated in patients, but SGOT, SGPT and total bilirubin were not. Levels of albumin and beta-globulin in patients were significantly lower than controls while gamma-globulin was elevated. Mean serum IgM levels in patients were elevated to nearly three-fold those of controls, but 35% of the individual patient values fell within the 95% range of control values. Some patients had extended prothrombin and thrombin times while fibrinogen levels were significantly elevated. No patients reported haemorrhage, and none was seen.

Occasional parasitic infections of man in Papua New Guinea and Irian Jaya (New Guinea).

Abstract: Most parasites of man in New Guinea are cosmopolitan species, widely distributed and highly prevalent in the island. Reports of other parasite infections are reviewed. This impoverished fauna inclu...