Currently, the laboratory diagnosis of toxocariasis, caused by Toxocara canis or T. cati, mainly relies on serological tests. Unfortunately, however, the specificities of most of the commercial tests that are available for the serodiagnosis of this disease are not very high and this may cause problems, especially in tropical countries where co-infections with other helminths are common. In an effort to develop a serological assay with improved specificity for the detection of Toxocara infection, an IgG(4)-ELISA based on a recombinant version (rTES-30USM) of the 30-kDa Toxocara excretory-secretory antigen (TES-30) has recently been developed. To produce the antigen, the TES-30 gene was cloned via assembly PCR, subcloned into a His-tagged prokaryotic expression vector, and purified by affinity chromatography using Ni(2+)-nitrilotriacetic-acid (Ni-NTA) resin. The performance of the ELISA based on the recombinant antigen was then compared with that of commercial kit, based on an IgG-ELISA, for the serodiagnosis of toxocariasis (Toxocara IgG-ELISA; Cypress Diagnostics, Langdorp, Belgium). Both assays were used to test 338 serum samples, including 26 samples from probable cases of toxocariasis. Assuming that all the probable cases were true cases, the assay based on rTES-30USM demonstrated a sensitivity of 92.3% (24/26) and a specificity of 89.6% (103/115) whereas the commercial kit exhibited a sensitivity of 100% (26/26) but a specificity of only 55.7% (64/115). The high sensitivity and specificity exhibited by the new IgG(4)-ELISA should make the assay a good choice for use in tropical countries and any other area where potentially cross-reactive helminthic infections are common.
Multidrug-resistant organisms cause late-onset ventilator-associated pneumonia (VAP). In a pilot, randomized and controlled study, the efficacy and safety of cefepime, in late-onset VAP in infants, have now been evaluated in Malaysia. Thirty children aged <1 year with late-onset VAP (i.e. VAP occurring 5 or more days after intubation) were randomized to receive cefepime or, as a control, ceftazidime. The clinical responses and the microbiological clearance of tracheal aspirates were evaluated in each arm. Adverse events, if any, were monitored clinically and by blood tests. Ten of the 15 children given cefepime and five of the 15 given ceftazidime showed a satisfactory clinical response (P<0.1). Cefepime appeared significantly better at clearing polymicrobial infections from tracheal aspirates. There were no fatalities in the cefepime arm but three in ceftazidime (P<0.1). The mean (S.E.) durations of antibiotic use were 9.4 (1.5) days for cefepime and 7.6 (1.0) days for ceftazidime (P>0.05). No serious adverse effects were observed in either arm. In conclusion, in late-onset VAP in infants, cefepime monotherapy appears to be at least as effective and safe as ceftazidime monotherapy, with better microbiological clearance.
Citridiol is an extract of the leaves of Corymbia citriodora (Myrtaceae), the lemon eucalyptus, and mostly consists of p-menthane-3,8-diol isomers. The effectiveness of this extract as a repellent against land leeches of the genus Haemadipsa (Haemadipsidae), primarily H. sylvestris, was tested in the laboratory and field, in Peninsular Malaysia. The formulation tested, Mosi-guard Natural spray, contained 40% (w/w) Citridiol in a base of ethanol, water and isopropanol. In the laboratory test, specimens of H. sylvestris that were placed within moist, untreated arenas enclosed by treated paper rings made numerous attempts to cross the rings but were prevented or delayed from crossing over, in a dose-dependent manner. Mortality was high among the leeches that attempted to cross over the paper rings that had been sprayed to saturation point but low among the leeches that attempted to cross over paper rings that had only been partially treated, with a droplet-spray. The field study was carried out using indices that were formulated to reflect the severity of leech attack and the degree of repellency. Heavy or moderate spraying of footwear and trouser legs (tucked into socks) not only gave complete protection against bites by H. sylvestris and H. picta but also provided high enough repellency to keep the treated footwear virtually free of leeches. Even a light spray greatly reduced the numbers of leeches on footwear and delayed their progression toward biting the test subjects, although it failed to prevent bites completely. There was no decline in the repellency of the Citridiol when hourly assessments were made over a 6-h test period in the field. The results of the study show that Citridiol is highly repellent as well as toxic to leeches, and can be effectively used to prevent leech bites in the field.
Histochemical demonstration of acid phosphatase activity in microfilariae gives sufficiently characteristic and consistent results for the differentiation of even closely related species. No difference could be detected among nocturnally periodic, nocturnally subperiodic and diurnally subperiodic Brugia malayi, but they could readily be distinguished from B. pahangi. Similarly, Dirofilaria repens could be readily distinguished from D. immitis and B. booliati from B. sergenti. The enzyme distribution pattern of a Malaysian rural strain of Wuchereria bancrofti was different from those of other regions.
Serum was collected from six adults participating in a field trial of sulfadoxine and pyrimethamine in combination which was being administered once monthly for malaria suppression. Samples were drawn during each of two consecutive months three hours, and 7, 14 and 28 days following a dose of 1 500 mg sulfadoxine. Serum sulfadoxine concentration was measured using the method of Bratton and Marshall (1939). Initial serum concentrations averaged 19-9 plus or minus 2-4 (SD) mg/100 ml and decayed to 6-2 plus or minus 2-8 mg/100 ml at 14 days. Serum sulfadoxine concentrations were still detectable at 28 days following a dose (2-1 plus or minus 1-5 mg/100 ml). Elimination half-time averaged 195 plus or minus 44 hours. The presistent serum concentrations of sulfadoxine following monthly doses documented here during field-use of this drug are in agreement with the successful clinical results reported for such a regimen (Lewis and Ponnampalam, 1974; O'Holohan and Hugoe-Mathews, 1971; Wolfensberger, 1971).