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S Geerts

Publications and source records attributed to S Geerts.

At least 73 records · Page 4Linked to original sources
PubMed1997

Diagnostic evaluation of PCR in goats experimentally infected with Trypanosoma vivax.

Six goats were experimentally infected with a stock of Trypanosoma vivax. Parasitaemia was weekly monitored by buffy coat and wet blood film examination during a period of 15 weeks and another 3 weeks following drug-treatment. Dried blood samples were tested by the polymerase chain reaction (PCR), using an extraction method with Chelex 100 (BioRad). PCR proved consistently more sensitive than the parasitological techniques.

Animals↗
PubMed1997

Prophylactic effects of isometamidium- and ethidium-sustained release devices against Trypanosoma congolense in cattle.

Two successive experiments were carried out in which three cows were treated by intramuscular injection of either 0.5 mg/kg isometamidium or 1 mg/kg ethidium and compared with another group of three cows which received a subcutaneously implanted sustained release device (SRD) containing the same dose of drug. The prophylactic effect of both drug formulations was evaluated by exposing the animals at monthly intervals to Glossina morsitans morsitans infected with Trypanosoma congolense. The average protection period using the isometamidium- and the ethidium-SRD was extended by a factor of 3.2 and 2.8, respectively in comparison with the intramuscular injection of the drugs. In the analysis of isometamidium concentrations in the serum of the animals using a competitive drug-ELISA the drugs remained present for much longer periods in the sera of the implanted animals than in those of the intramuscularly treated cattle. The animals were still protected, however, a long time after the disappearance of detectable drug levels in the serum. No difference in drug sensitivity could be observed, when breakthrough isolates were compared from animals which received the ethidium-SRD and those treated intramuscularly, although a slight loss sensitivity occurred in the breakthrough isolates as compared to the parent trypanosome population.

Animals↗
PubMed1997

The interaction of Trypanosoma congolense and Haemonchus contortus in Djallonké sheep.

The interaction between Trypanosoma congolense and Haemonchus contortus was studied in 5 groups of 8 Djallonké sheep. Two groups received a single infection with either H. contortus or T. congolense, and 2 groups were infected with T. congolense followed by H. contortus (TH) or vice versa (HT). One group was kept as uninfected controls. Mortality due to infection was observed only in the dual infection groups. In the TH group, the effects were more acute whereas in the HT group they were more chronic. No significant differences in weight gain could be demonstrated between infected and control groups. Djallonké sheep are able to withstand a single infection with either T. congolense or H. contortus, which confirms their trypanotolerant nature and provides preliminary indication of resistance against helminth infections. However, when exposed to successive infections with both parasites, some of the animals lose this tolerance.

Animals↗
PubMed1997

Anthelmintic resistance in human helminths: Learning from the problems with worm control in livestock.

During the past decade, the prevalence of anthelmintic resistance in some economically important helminths of sheep, goats and horses has increased dramatically. In some regions of Australia, South America and South Africa, anthelmintic resistance has become a serious threat to the survival of the sheep industry. Mass treatment programmes and exclusive reliance on anthelmintics for worm control in livestock are amongst the most important reasons for the development of anthelmintic resistance. In this article, Stanny Geerts, Gerald Coles and Bruno Gryseels draw the attention to a number of errors that have occurred in the control of helminths in livestock and that should be avoided in the control of worms in humans.

Journal Article↗
PubMed1997

Double-blind randomized controlled study of the efficacy and tolerability of two reversible monoamine oxidase A inhibitors, pirlindole and moclobemide, in the treatment of depression.

The aim of this double-blind randomized study was to compare the efficacy and the tolerability of moclobemide (300-600 mg daily) and pirlindole (150-300 mg daily), two reversible inhibitors of MAO-A (RIMAs), in the treatment of depression. In total 116 patients were included in the trial, 111 patients (52 patients on pirlindole and 59 patients on moclobemide) were evaluable for efficacy and safety, and 77 patients completed the whole study (42 days of administration). Both treatments produced highly significant improvements in the Hamilton Depression Rating Scale (HDRS) score, the Hamilton Anxiety Rating Scale (HARS) score and the Montgomery-Asberg Rating Scale (MADRS) score from day 7 to day 42. The pattern of development of the three scores in the two groups did not differ significantly. After 42 days of treatment, an improvement of > or = 50% in the HDRS score was noted in 80% and 67% of patients in the pirlindole and moclobemide groups, respectively. A total of 30 (58%) patients on pirlindole and 33 (56%) patients on moclobemide experienced side-effects that were considered to be possibly or probably related to the medication. The differences between the two drugs were non-significant for all types of side-effect, with the exception of dry mouth and tachycardia, which were significantly more frequent with moclobemide.

Adolescent↗
PubMed1996

Comparison of single and trickle infections of pigs with eggs of the Asian Taenia.

Two groups of seven Belgian Landrace piglets each were either infected with a single dose of 3000 or with five consecutive doses of 600 Asian Taenia eggs at weekly intervals. Nine weeks after the first infection all pigs were autopsied and the number of metacestodes was obtained by slicing the liver. There were no significant differences between the mean number of viable or dead cysts present in both groups of animals. Only very low numbers of living metacestodes were found: 0.4% (3/779) of the total number of cysts present in the single infection group and 1.8% (13/707) in the trickle infection group. Circulating antigens could be detected in only four out of 13 animals and no differences in antibody kinetics were present between the two groups of pigs. The presence of high numbers of degenerated cysts in experimental as well as in field conditions seems to indicate that the biotic potential of the Asian Taenia is rather low.

Animals↗
PubMed1996

Comparative evaluation of the prophylactic effect of slow release devices containing homidium bromide and isometamidium on Trypanosoma congolense in rabbits.

Two consecutive experiments were carried out to evaluate the prophylactic effect of biodegradable slow release devices (SRD), containing either isometamidium or homidium bromide. Rabbits subcutaneously implanted with SRD, were challenged with different Trypanosoma congolense stocks at regular intervals between 1 and 6.5 months after treatment. In a first experiment the efficacy of two types of isometamidium-SRD (poly(D,L-lactide) and poly(D,L-lactide-co-glycolide)) was compared with the classical intramuscular (i.m.) injection of the drug. Since the former polymer gave an average protection period, which was much longer than the other isometamidium formulation, a second experiment was carried out to evaluate the prophylactic effect of poly(D,L-lactide) SRD, containing either isometamidium or homidium bromide, with that of the i.m. injections of the same drugs at a dose of 1 mg kg-1. The average protection period of the homidium bromide SRD was significantly longer than that of the i.m. injected drug (112 vs. 49 days). No significant difference was obtained, however, when isometamidium was administered either as a SRD or as an i.m. injection. The average protection periods were, respectively, 106 +/- 37 days and 84 +/- 18 days. When breakthrough isolates derived from SRD-treated animals were compared with the original stocks of T. congolense, the former showed some loss of sensitivity to homidium bromide. No difference in sensitivity was observed, however, for isometamidium.

Animals↗
PubMed1996

Experimental single and trickle infections of cattle with Taenia saginata: studies of immunodiagnosis.

Two groups of 12 calves were given either a single infection dose of 30,000 Taenia saginata eggs (group A) or trickle infected with 12 x 2500 T saginata eggs (group B). The calves were killed 16, 22 or 54 weeks after infection and the numbers of viable and dead parasites were counted by slicing selected organs and muscles of half of the carcases. The total numbers of cysts and the numbers of viable cysts were higher in group A than in group B. Within the two groups there were no significant differences between the numbers of cysts at the three dates of slaughter. Comparable results were obtained by using an ELISA and a dot blot procedure for the detection of antibody in the serum of the infected calves; an initial increase in response during the first 10 weeks after infection was generally followed by a gradual decline. When using a monoclonal antibody-based ELISA for the detection of circulating antigens, the sera from all the 14 animals which had no viable cysts or only dead cysts at slaughter did not react with the monoclonal antibodies. Calves 122 and 123, which harboured two and 122 viable cysts, respectively, reacted positively during the late phase of the infection to the antigen-detecting ELISA. However, several other animals which harboured between two and 41 viable cysts at slaughter did not react.

Animals↗
PubMed1996

A double-blind randomized placebo-controlled study of the efficacy and safety of pirlindole, a reversible monoamine oxidase A inhibitor, in the treatment of depression.

The efficacy and safety of pirlindole (300 mg/day), a new reversible inhibitor of monoamine oxidase A, have been evaluated in a multicentre placebo-controlled double-blind randomized trial in 103 in-patients suffering from unipolar major depression (DSM-III-R 296.2, 296.3) over a 42-day period after a run-in placebo period of 6 days. Pirlindole produced a significantly greater decrease than placebo in the Hamilton depression score (from day 28), the Hamilton anxiety score (from day 28) and the Montgomery-Asberg depression score (on day 42). On day 42, the Hamilton depression score was < or = 7, > or = 8 and < or = 15, or > or = 16 in 21%, 45% and 34%, respectively, in the placebo group compared to 72%, 24% and 3.4%, respectively, in the pirlindole group (P < 0.001). The differences between the two groups in terms of tolerance and safety were not statistically significant.

Adult↗
PubMed1995

Development of a dot-enzyme immunoassay for the detection of circulating antigen in cattle infected with Taenia saginata cysticerci.

A monoclonal antibody-based dot-ELISA was developed for the detection of antigen in the sera of cattle with Taenia saginata cysticercosis. After pretreatment of the sera with trichloroacetic acid, antigen could be detected in experimentally infected animals from five weeks after infection. The assay distinguished animals harbouring living cysts from those carrying only dead cysts. A reliable diagnosis of animals harbouring less than 100 cysticerci was not possible, but in cattle with more than 100 living cysticerci the sensitivity was 87.5 per cent; the specificity of the test was 93.5 per cent. These values were very similar to those obtained with a sandwich ELISA.

Animals↗
PubMed1995

Failure of experimental infection of baboons (Papio hamadryas) with the eggs of Asian Taenia.

The infectivity of the eggs of Asian Taenia sp. for humans is not known. Using baboons (Papio hamadryas) as a model to extrapolate the findings, three animals were exposed per os with 1000, 10,000 and 50,000 infective eggs of the Asian Taenia sp. The serological, biochemical, haematological and parasitological (based on necropsy) results show that baboons are refractory to the infection. It is concluded that the Asian taeniid eggs may fail to develop in man.

Animals↗
PubMed1995

Characterization of epitopes on excretory-secretory antigens of Taenia saginata metacestodes recognized by monoclonal antibodies with immunodiagnostic potential.

Four monoclonal antibodies (MoAbs) produced against the excretory-secretory (ES) antigens of Taenia saginata metacestodes are currently used for the detection of circulating antigen in the sera of cattle with bovine cysticercosis. The epitopes recognised by these MoAb were characterized by periodate oxidation, alkaline borohydride and heat treatment, trichloracetic acid precipitation, enzymatic proteolysis and deglycosylation of the ES-products. These results together with those of the homologous sandwich, inhibition and competition ELISAs showed that three repetitive epitopes are recognized, which are present on the tegument and on the ES-products of T. saginata metacestodes. They are different from phosphorylcholine and seem to be either of carbohydrate or partly carbohydrate/partly protein nature.

Animals↗
PubMed1995

[Anthelmintics resistance in gastrointestinal nematodes in domestic animals].

In Belgium benzimidazole resistance has been reported in 28% of the sheep farms and 29 to 50% of the studs. In several member states of the European Union the prevalence of anthelmintic resistance (AR) is even higher than in Belgium, although AR is nearly absent in some countries of Southern Europe. AR is particularly widespread in certain nematodes of sheep, goats and horses in Europe, whereas only sporadic cases of AR have been reported in helminths of cattle. In Belgium only one case of AR has been described in goat and one in cattle; no surveys for AR have been carried out in pigs. The main helminth species, in which AR has been observed, are Haemonchus contortus, Ostertagia circumcincta and Trichostrongylus spp. in small ruminants, the Cyathostominae in horses and Oesophagostomum spp. in pigs. Resistance has developed particularly against the benzimidazoles and to a lesser extent against the levamisole/morantel group. Up to now the prevalence of ivermectin resistance remains low, but the number of cases is increasing during recent years. Due to the low sensitivity of the currently used techniques for the detection of AR (egg count reduction test and in vitro egg hatch test) the available figures underestimate the prevalence of AR. Finally, possible control measures are discussed in order to avoid or to delay the development of resistance.

Animals↗
PubMed1994

Recommendations for the control of anthelmintic resistant nematodes of farm animals in the EU.

As a result of a recent European Union meeting on anthelmintic resistant nematodes of farm animals, a list was made of nine proposals for research and five to control anthelmintic resistance. The most important were the need to have standardised and new tests to monitor the development and spread of resistant nematodes in sheep, goats, horses, cattle and pigs, and for education of veterinary surgeons and farmers in the optimal control strategies to be used to delay the development of anthelmintic resistance in nematodes.

Animals↗
PubMed1994

Evaluation of the activity of Ambrosia maritima L. against Schistosoma mansoni infection in mice.

Two groups of mice, showing a patent infection of Schistosoma mansoni, were orally treated with an alcoholic extract of Ambrosia maritima leaves. One group received a single dose, equivalent to 15 g leaves/kg body weight, whereas the other received 5 consecutive doses. The schistosomicidal activity of the plant extract was evaluated 1 week after treatment using 4 parameters: worm load, motility of the worms, oogram and the number of eggs in the liver and intestinal wall. In comparison to the control group no effect at all was observed in the mice who received one single dose of A. maritima. In the group receiving 5 consecutive daily doses, however, the percentage of immature eggs in the intestinal wall had slightly decreased as compared to the controls, but this was compensated by an increase in the number of eggs in the liver. Given the high doses of plant extract used, it is concluded that oral administration of A. maritima has a negligible effect on S. mansoni in mice.

Administration, Oral↗
PubMed1994

Effect of Ambrosia maritima on Anopheles stephensi and Aedes aegypti.

The toxicity of the molluscicidal plant Ambrosia maritima L. was evaluated against Anopheles stephensi and Aedes aegypti. In the larvicidal assays a negligible mortality was observed in both species after application of the dried leaves in the water at concentrations up to 2000 mg/l. When the powdered leaves were applied at the surface of the water, however, up to 38% of the larvae of A. stephensi were killed at 2000 mg/l. Virtually no inhibitory effect on the larval growth of both species was noticed. It can be concluded that Ambrosia maritima has little or no effect on the larvae of A. stephensi or Ae. aegypti.

Aedes↗
PubMed1994

Antibacterial and molluscicidal phenolic acids from Spondias mombin.

Spondias mombin L. (Anacardiaceae), used in traditional medicine because of its antimicrobial properties, was found to contain a series of 6-alkenyl-salicylic acids. They were isolated from the ethanolic extract of leaves and stems of Spondias mombin by a combination of chromatographic methods. Their structure was determined by NMR and MS techniques as (17:3), (17:2) and (17:1) pelandjuaic acid [or 6-(8'Z,11'Z,14'Z-heptadecatrienyl)-salicylic acid, 6-(8'Z,11'Z-heptadecadienyl)-salicylic acid, and 6-(10'Z-heptadecenyl)-salicylic acid, respectively], 6-(12'Z-non-adecenyl)-salicylic acid, and 6-(15'Z-heneicosenyl)-salicylic acid, the two last compounds being new ones. These phenolic acids were shown to have a pronounced antibacterial effect against Bacillus cereus, Streptococcus pyogenes, and Mycobacterium fortuitum (minimal bactericidal concentration in a concentration range of 3-25 micrograms/ml), and a molluscicidal effect against the snail Biomphalaria glabrata, an intermediate host in the schistosome life cycle. Because of their high molluscicidal activity (LC90 down to 1-3 ppm), these long-chain salicylic acid derivatives may be important tools in the prevention of schistosomiasis.

Animals↗