Publications by authors named "Clive J Shiff"

Article Synopsis
  • Seasonal malaria transmission in Africa is linked to rainfall, but cases can still occur during the dry season due to specific conditions that support mosquito activity.
  • This study used negative binomial regression models to analyze the relationship between humidity from peri-domestic trees and malaria incidence in Zambia over three years.
  • Results indicated that humidity, particularly during the dry season, significantly influenced malaria cases, while other factors like temperature, elevation, and rainfall were less impactful.
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Cystic echinococcosis (CE) is a major neglected tropical zoonotic disease caused by the tissue-dwelling larval stage of the cestode parasite Echinococcus granulosus. For individuals suspected of CE, the diagnostic standard is imaging using ultrasonography, X rays, or computed tomography. These resource-demanding and expensive procedures are rarely available in endemic rural areas where CE is most prevalent.

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For epidemiological work with soil transmitted helminths the recommended diagnostic approaches are to examine fecal samples for microscopic evidence of the parasite. In addition to several logistical and processing issues, traditional diagnostic approaches have been shown to lack the sensitivity required to reliably identify patients harboring low-level infections such as those associated with effective mass drug intervention programs. In this context, there is a need to rethink the approaches used for helminth diagnostics.

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Schistosomes are easily transmitted and high chance of repeat infection, so if control strategies based on targeted mass drug administration (MDA) are to succeed it is essential to have a test that is sensitive, accurate and simple to use. It is known and regularly demonstrated that praziquantel does not always eliminate an infection so in spite of the successes of control programs a residual of the reservoir survives to re-infect snails. The issue of diagnostic sensitivity becomes more critical in the assessment of program effectiveness.

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Article Synopsis
  • Rapid diagnostic tests (RDTs) for Plasmodium falciparum, while useful for identifying malaria in low transmission areas, struggle with sensitivity for low-density infections and can't detect certain strains or other malaria species.
  • In a study of over 3,200 participants in Zambia, RDTs identified only 42 positive cases, whereas nested PCR detected 57 positives, highlighting RDTs' low sensitivity of just 17% compared to PCR results.
  • Despite high specificity (>99%), the study suggests that missed detections in RDTs were more about low parasite levels than issues with the pfhrp2 gene itself, complicating malaria diagnostics.
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Vector control has been at the core of successful malaria control. However, a dearth of field-oriented vector biologists threatens to undermine global reductions in malaria burden. Skilled cadres are needed to manage insecticide resistance, to maintain coverage with current interventions, to develop new paradigms for tackling 'residual' transmission and to target interventions as transmission becomes increasingly heterogeneous.

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Background: Plasmodium falciparum transmission has decreased significantly in Zambia in the last decade. The malaria transmission is influenced by environmental variables. Incorporation of environmental variables in models of malaria transmission likely improves model fit and predicts probable trends in malaria disease.

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Differential diagnosis of Schistosoma mansoni and S. haematobium, which often occur sympatrically in Africa, requires both urine and stool and the procedures are low in sensitivity. The standard diagnostic tests, such as Kato-Katz (KK) for S.

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Background: In places where malaria transmission is unstable or is transmitted under hypoendemic conditions, there are periods where limited foci of cases still occur and people become infected. These residual "hot spots" are likely reservoirs of the parasite population and so are fundamental to the seasonal spread and decline of malaria. It is, therefore, important to understand the ecological conditions that permit vector mosquitoes to survive and forage in these specific areas.

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Diagnosis for intestinal Schistosoma mansoni lacks sensitivity and is arduous to conduct. The standard diagnostic tests, Kato-Katz (KK) and circulating cathodic antigen (CCA) both lack sensitivity and with KK, require obtaining, transporting, and examining fresh stool. We compared diagnostic efficacy of KK, CCA, and polymerase chain reaction (PCR) to detect S.

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Most measurements of malaria are based on cross-sectional data and do not reflect the dynamic nature of transmission, particularly when interventions require timely data for planning strategies. Such data can be collected from local rural health centres (RHCs) where the infrastructure is sufficiently developed and where rapid diagnostics are in use. Because in rural areas, the population served by RHC is reasonably static, the regular use of malaria rapid diagnosis in RHCs can provide data to assess local weekly incidence rates, and such data are easily dispersed by cell phones.

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Surveillance for drug-resistant parasites in human blood is a major effort in malaria control. Here we report contrasting antifolate resistance polymorphisms in Plasmodium falciparum when parasites in human blood were compared with parasites in Anopheles vector mosquitoes from sleeping huts in rural Zambia. DNA encoding P.

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Objective: To evaluate the clinical utility of quantitative nuclear morphometry--i.e., alteration in nuclear size/shape, DNA content and chromatin structure-of intact cells obtained from the sediment of urine specimens collected from people living in an area highly endemic for Schistosoma haematobium in Ghana.

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Background: Current detection or screening for malaria infection necessitates drawing blood by fingerprick or venipuncture, which poses risks and limitations for repeated measurement. This study presents PCR detection of Plasmodium falciparum in human urine and saliva samples, and illustrates this potential application in genotyping malaria infections.

Methods: Urine and saliva were obtained from 47 thick film positive and 4 negative individuals one day after collection of blood slides and filter paper blood spots.

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Background: The morbid effects of urinary bilharziasis are becoming more evident with the advent of sophisticated diagnostics such as ultrasound. However, such diagnosis of Schistosoma haematobium morbidity is often hampered by lack of funds, proper equipment, or training.

Objective: We performed a cross-sectional investigation of schoolchildren in a highly endemic area of east central Zimbabwe in order to assess the utility of a number of simple clinical indicators to predict Schistosoma haematobium morbidity.

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Disease outcome in persons infected with Schistosoma haematobium varies dramatically, ranging from mild symptoms to severe damage of the kidneys and/or bladder. We used ultrasonography to characterize the extent of urinary tract pathology of infected children in Zimbabwe, and random genetic markers to examine the relationship between genetic diversity of S. haematobium and clinical outcome.

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Clinical outcome of Schistosoma haematobium infection may vary significantly, ranging from mild symptoms to severe damage of urinary tract organs. This present study was undertaken to assess the relationship of a number of epidemiological and parasitological parameters with disease outcome in children from rural Zimbabwe. We surveyed 551 primary school students from three schools in the Chikwaka Communal Lands for schistosomiasis; 59.

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