Abstract. To determine which species and populations of Anopheles transmit malaria in any given situation, immunological assays for malaria sporozoite antigen can replace traditional microscopical examination of freshly dissected Anopheles. We developed a wicking assay for use with mosquitoes that identifies the presence or absence of specific peptide epitopes of circumsporozoite (CS) protein of Plasmodium falciparum and two strains of Plasmodium vivax (variants 210 and 247). The resulting assay (VecTest TM Malaria) is a rapid, one-step procedure using a`dipstick' test strip capable of detecting and distinguishing between P. falciparum and P. vivax infections in mosquitoes. The objective of the present study was to test the efficacy, sensitivity, stability and field-user acceptability of this wicking dipstick assay. In collaboration with 16 test centres world-wide, we evaluated more than 40 000 units of this assay, comparing it to the standard CS ELISA. The`VecTest TM Malaria' was found to show 92% sensitivity and 98.1% specificity, with 97.8% accuracy overall. In accelerated storage tests, the dipsticks remained stable for >15 weeks in dry conditions up to 45 C and in humid conditions up to 37 C. Evidently, this quick and easy dipstick test performs at an acceptable level of reliability and offers practical advantages for field workers needing to make rapid surveys of malaria vectors.
It is essential for malariologists and researchers to have simple and accurate means of assessing the threat of Plasmodium parasites. An attempt was therefore made to re-standardize one of the circumsporozoite (CS) ELISA that can be used to detect and quantify the circumsporozoite antigens of P. falciparum and P. vivax. A two-site, 'sandwich' ELISA based on a monoclonal antibody was used to test for the CS antigen and sporozoites of each Plasmodium species simultaneously. Using the resultant optical-density values, standard curves, that permit the number of sporozoites in an infected mosquito to be estimated from the quantification of the CS antigen, were constructed. Using these plots and the CS ELISA, the presence of just 12.5 sporozoites (i.e. 0.8 pg CS antigen) of P. falciparum, four sporozoites (3.2 pg antigen) of P. vivax-210 or 12.5 sporozoites (32.0 pg antigen) of P. vivax-247 could be demonstrated.
Plasmodium malariae occurs in various tropical regions throughout the world and causes low, yet significant, levels of morbidity in human populations. One means of studying the ecology and frequency of this parasite is by measuring sporozoite loads in the salivary glands of infected mosquitoes. An effective, species-specific test that can be used to detect the presence of sporozoites in mosquitoes is the circumsporozoite ELISA. The aim of the present study was to standardize the circumsporozoite ELISA for P.malariae, by setting quantification parameters using, as antigen, either a synthetic peptide or extracts of whole sporozoites. The standard quantification curves produced indicated that the assay had a lower threshold of sensitivity of 250 sporozoites in a 50-microl sample, equivalent to about 1250 sporozoites in a mosquito.
Introduction Type 2 diabetes mellitus (T2D) is associated with poor health outcomes and tight glycaemic targets are questionable in those aged over 70 years. We examined whether people with T2D admitted to emergency department (ED) with a fall, were more likely to have greater frailty, co-morbidity burden, or risk factors for falls and whether use of insulin or gliclazide was associated with poor clinical outcomes. Methods The Older Persons Assessment Service (OPAS) is a local emergency department service which accepts patients on frailty criteria. The OPAS databank was retrospectively analysed for people with T2D admitted with a fall between June 2020-September 2022. We examined clinical outcomes relating to medication, age, Charlson co-morbidity index (CCI) and clinical frailty score (CFS). Results 1081 patients were included: 294 (27.2%) with T2D and a mean HbA1c of 53.9 (±15.8) mmol/mol [7.1%]. People with T2D had a similar mean CFS and age compared to those without T2D, but higher mean CCI (7.0±2.2 vs 5.9±2.1, p<0.001). Of those people with T2D, 175 (59.5%) and 240 (81.6%) had a HbA1c ≤53 mmol/mol [7.0%] and ≤64 mmol/mol [8.0%], respectively. In total, 48 (16.3%) people with T2D were identified to have a capillary blood glucose below 4.0 mmol/L on admission to the emergency department. People with T2D treated with insulin and/or gliclazide had a greater mortality (36.6% vs 23.6%, p<0.05), greater frequency of hypoglycaemia (35.4% vs 11.8%, p<0.001), and greater HbA1c (65.5±17.2 mmol/mol [8.2] vs 48.9±12.1 mmol/mol [6.6%]) compared to those who used other agents. People with T2D were not more likely to live in deprived areas. Conclusion Falls are a significant burden, and hypoglycaemia-inducing medication may contribute to the greater mortality observed in people with T2D. Clinician awareness can support de-prescribing for patients with frailty and HbA1c <64mmol/mol. There should be increased awareness of the impact of hypoglycaemia, especially in those using insulin or gliclizade.
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