Tropenmedizin und Parasitologie最新文献

The isoenzyme patterns (electrophoresis on thin-layer starch gel) and the human serum resistance (blood incubation infectivity test) of a Trypanozoon stock from a dog and 14 stocks from man in Liberia were examined. The complete conformity of criteria for man-infectivity of the dog stock with 5 human stocks and the very close similarity to the 9 remaining stocks from the same epidemiological locality indicates the dog as a reservoir host of gambiense sleeping sickness.

The prevalence of Toxoplasma gondii in indigenous meat animals in the Niger Delta area of Nigeria was measured by serological examination of antibody using the Sabin-Feldman dye-test. Of 300 each of cattle, sheep, goats and pigs examined, 32.8%, 75.2%, 81.6% and 69.2% respectively, possessed significant antibody titres. These results indicate that there exists within meat animals in this area, a considerable reservoir of Toxoplasma which has the potential for transmission as zoonosis to man.

The efficacy of oltipraz as a schistosomicidal drug was investigated in Gabonese children suffering from urinary schistosomiasis in the dosages of 1 X 25 mg/kg body weight, 1 X 35 mg/kg body weight, and 2 X 20 mg/kg body weight and compared to praziquantel, 2 X 30 mg/kg body weight. The study was undertaken in 165 patients, and follow-up investigations were carried out 6 weeks and 12 weeks after treatment. Oltipraz showed less efficacy compared to praziquantel when dosages of 1 X 25 and 1 X 35 mg/kg body weight were given. However, oltipraz 2 X 20 mg/kg body weight was equivalent to praziquantel 2 X 30 mg/kg body weight. Parasitological cure was obtained in 79% of patients treated by oltipraz and 81% of patients treated by praziquantel. Side effects were insignificant in both treatment groups. Thus, the same parasitological cure could be achieved by oltipraz as well as by praziquantel, but with a lower dosage of oltipraz.

158 school children from Lambarene and its surroundings suffering from intestinal manifestations of schistosomiasis due to Schistosoma intercalatum, Schistosoma haematobium, or mixed infections were randomly allocated to patient groups to be treated with oltipraz and praziquantel respectively. Oltipraz was tested in three dosage regimens, i.e., 1 X 25 mg/kg, 1 X 35 mg/kg, and 2 X 20 mg/kg and compared to 2 X 30 mg/kg praziquantel in each of the treatment groups. 45 days and 90 days after treatment, the children were thoroughly investigated. Rectoscopy was only performed in part of the children. The number of children with viable egg excretion had significantly dropped after therapy (p less than 0.001). Parasitological cure after 90 days was obtained in 86% of patients treated with 2 X 20 mg oltipraz and 90% of patients treated by praziquantel. A comparative effectiveness was achieved with the other dosage regimens of oltipraz, too. The efficacy of the new schistosomicid oltipraz is identical with that of praziquantel for patients with intestinal manifestation. The rectal biopsies taken 45 days and 90 days after therapy still contained numerous eggs which were mostly calcified or granulated.

In three types of trypanosomes with low virulence, trypanosome numbers increased by a factor of 18-21 per day on average during prepatency and by a factor of 70-219 on average from the first to second day of patency. By contrast, a very virulent trypanosome variant showed an average increase of trypanosome numbers per day by 32 and 28 during prepatency and early patency, respectively. --In detailed studies, trypanosomes of low virulence exhibited a rapidly rising parasitemia in early patency which lasted for 20-30 hours and was followed by a plateau of slowly rising and falling parasitemia. Trypanosomes of high virulence showed a constant logarithmic increase of their numbers, slowing down at concentrations above antilog 5.5 per microliters of blood. In mild trypanosomes with peak parasitemias of antilog 5-5.7 per microliters of blood, after low dose infections the primary parasitemia was abruptly terminated after 70-100 hours of patency, obviously by the action of antibody. After massive infections, the parasitemia was terminated at 109-122 hours after infection. --In trypanosomes with higher peak parasitemias, primary parasitemias were seen to last longer, in some cases for 7 to 12 days. --Mice infected with low doses of highly virulent trypanosomes died with high parasitemias after some 60-90 hours of patency, before antibodies could normally become effective. After massive infections they died at 40-60 hours after infection. There is clearly no need to invoke non-immunogenicity of these trypanosomes or immunosuppression by these trypanosomes to explain this course of the infection.

A field trial in Egypt of the plant molluscicide, Ambrosia maritima is described. Applications of 140, 70 and 35 mg/l-1 dry, whole plant were made to irrigation canals and drains in June. The treatment effect took between 1 and 5 weeks to become fully established. The reduction in the numbers of alive Biomphalaria alexandrina snails was generally more than 90% and was virtually the same at all treatment levels and in both types of watercourse. The snail population remained at a low level for at least 3 months until September-October. The possible use of a single, annual application in April or May in controlling snails throughout the main schistosomiasis transmission season in Lower Egypt is suggested.

Two pigs infected with Trypanosoma brucei gambiense developed low parasitemia which became undetectable after 6 months; on autopsy 13 months after infection they showed no histopathological alterations. --Five of six pigs infected with a Trypanosoma brucei brucei strain from the Ivory Coast developed low parasitemia (up to about antilog 6.5 per ml of blood) which became progressively lower but was detectable up to one year after infection. On autopsy they showed interstitial myocarditis and meningo-encephalitis; during the course of the infection, the first became milder, the second more intense; no trypanosomes were seen in the tissues. One of these pigs developed a parasitemia of up to antilog 8 and died 172 days after infection from bacterial pneumonia, histologically it had severe myocarditis with many trypanosomes in the tissue and mild meningo-encephalitis. --Three pigs infected with a Trypanosoma brucei brucei strain from the Serengeti died 47, 68, 130 days after infection. The first dying pig had a high terminal parasitemia, in the others, the parasitemia was low until the end, being only detectable by the hematocrit centrifugation technique or by mouse passage. At autopsy, all showed massive myocarditis and interstitial nephritis with masses of extravascular trypanosomes, moderate meningo-encephalitis with very few trypanosomes, and widespread colonization of other organs and tissues by trypanosomes, still without marked cellular infiltrations.

The involvement of the brain, lungs and kidneys was studied in a lethal rat malaria. Lewis inbred rats were infected with Plasmodium berghei K173. The disease proved fatal within 10-14 days. Parasitaemia showed an increase of up to 43% parasitised red blood cells on Day 10 p.i. The haematocrit decreased from 50% to 12%. The systolic blood pressure dropped from 99 to 56 mmHg. The lactate dehydrogenase activity rose to 2,543 U/l. BUN and serum creatinine doubled during the course of the disease. The transaminases increased tenfold and the cholinesterase decreased from 943 U/l to 271 U/l. Morphologically the kidneys showed an immune complex glomerulo-nephritis with a normal tubulo-interstitial system. The brain, heart and lungs were normal by light microscopic examination. Marked anaemia and shock were the main causes of death in the above-mentioned specimen rat, showing that the course of the disease is significantly different from lethal infections in humans with Plasmodium falciparum who show severe pulmonary, renal and cerebral complications.

The effects of mebendazole, levamisole, diethylcarbamazine citrate (DEC-C), and the combination of mebendazole and levamisole, on adult Onchocerca volvulus and on the in utero development of microfilariae was studied in nodules excised from patients in Southern Mexico. Adult worms isolated from patients treated with mebendazole showed a reduction in mobility and contained 40 times fewer developing microfilarial forms than did worms from untreated patients. Most of the developmental forms found in adult worms from mebendazole-treated patients were either oocytes or early morulae, with more mature forms being scarce or morphologically abnormal. Treatment with levamisole had a similar effect on embryogenesis, however it was much less marked. The number and distribution of developing forms in worms from patients treated with DEC-C was similar to that found in the control groups. The effect of the same three drugs on microfilariae in vitro was also tested. DEC-C at concentrations of 0.5 microgram - 2000 micrograms/ml did not have any obvious effect on motility or morphology of the worms provided the pH was maintained at physiological levels; levamisole also had no effect in vitro. Mebendazole induced the death of microfilariae when used at concentrations greater than 100 micrograms/ml, however these levels are greater than those found in the blood of patients under treatment. The optimal conditions for short-term maintenance of O. volvulus microfilariae in culture, are discussed. It is apparent from these studies that mebendazole has an effect on the maturation of microfilariae in utero and may also, at high concentrations, have a direct effect on mature microfilariae.

During a serological Brucella survey in Bahr el Ghazal Province (Southern Sudan), 6.5% of a total of 5982 randomly selected cattle of the Dinka tribe from 303 herds investigated showed positive results. Herds of bigger size were found to be more frequently infected than smaller herds. From 1228 randomly selected cattle of the Fellata tribe (Red Bororo race), 22.5% produced a positive reaction. Here, reactors were detected in 71 from a total of 72 herds tested (98.5%). Among the Dinka cattle, the number of reactors rose steadily in correspondence to the age of the animals. A somewhat more pronounced increase of reactors was observed in animals 4-8 years of age. On the other hand, the number of reactors in the Fellata herds increased rapidly between the age of 2-4 years. Thereafter, this infection rate did not change significantly any more. The results indicated that a significant portion (37.1%) of reactors graded positive (n = 665) expressed only low titers (less than or equal to 1:40) in the SAST. Those titers were even more numerous (49.1%) among the positive reactors belonging to cattle below the age of 4 years.