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1.
Diagnosis of clinical malaria remains difficult, especially in areas where a high proportion of the asymptomatic population have parasitaemia, for the symptoms and signs of malaria overlap with those of other common childhood diseases, such as acute lower respiratory tract infections. However, a study of symptoms and signs in a group of children who presented to Farafenni Health Centre, The Gambia with a history of recent fever identified a group of signs and symptoms which were strong predictors of malaria as opposed to other febrile illnesses. Using these predictors, an algorithm was developed which could be used by fieldworkers and which had a similar sensitivity and specificity for the diagnosis of malaria as that of an experienced paediatrician working without laboratory support. This algorithm has been validated prospectively on 518 children who presented to the Medical Research Council clinic at Basse, The Gambia with fever or a history of recent fever during a 10-month period. A fieldworker obtained a detailed history from the parent or guardian of each child and performed a clinical examination which included measurement of axillary temperature and respiratory rate. Packed cell volume was measured and a thick smear was examined for malaria parasites. A malaria score, based on the presence or absence of malaria-related signs and symptoms, was determined for 382 children who were seen at the clinic during the high transmission season. Using the cut-off score which was optimal during the previous retrospective study, a sensitivity of 70% and a specificity of 77% for a diagnosis of malaria was obtained. The optimal cut-off score for the Basse population was a score of 7; this gave a sensitivity of 88% and a specificity of 62%, figures comparable to those obtained by an experienced paediatrician without laboratory support.  相似文献   

2.
Introduction: In areas of low-to-moderate risk of malaria transmission, the World Health Organization recommends parasitic confirmation before treatment. Such areas have usually low budget for health care and malaria diagnosis is mostly based on clinical assumption. Algorithms have been developed to improve health care providers’ identification of clinical malaria and could be used as screening to reduce the number of individuals requiring parasitic confirmation before treating. Methods: Prospective clinical and parasitological data were collected from inhabitants of four villages from March 1984 through March 1985. Symptoms and signs recorded by physicians were used in multivariate models to test the best predictors of malaria. Sensitivity and specificity were calculated for various cut-offs of scores and compared to clinical diagnosis. Results: A total of 8.941 individuals were evaluated during the 1-year period of data collection. The overall prevalence of malaria parasitemia was 19.7% (n = 1762). Of the 4280 people evaluated during the high season period, 24% (n = 1024) presented any parasitemia, 55.3% (566/1024) due to Plasmodium falciparum. The final clinical algorithm included history of fever, rigors, headache, absence of myalgia, backache or cough, nausea or vomiting, and splenomegaly on examination as predictable variables. At a cut-off score of 2.0, the sensitivity of the algorithm was higher for the entire sample (57% vs. 43%), for high season period (70% vs. 53%), for children less than 6 years of age (59% vs. 40%), for individuals with parasitemia due to P. falciparum (65% vs. 48%), and for high P. falciparum parasitemic individuals at high season (84% vs. 68%). However, specificity was usually lower unless a higher cut off was used, in which case the gain in sensitivity by using the algorithm was reduced. Conclusion: In low-to-moderate transmission areas in which health related resources are scarce, a clinical algorithm increases the identification of real cases of malaria and could be used as screening for further parasitic identification.  相似文献   

3.
The algorithm developed for the integrated management of childhood illness (IMCI) provides guidelines for the treatment of paediatric malaria. In areas where malaria is endemic, for example, the IMCI strategy may indicate that children who present with fever, a recent history of fever and/or pallor should receive antimalarial chemotherapy. In many holo-endemic areas, it is unclear whether laboratory tests to confirm that such signs are the result of malaria would be very relevant or useful. Children from a holo-endemic region of Tanzania were therefore checked for malarial parasites by microscopy and by using two rapid immunochromatographic tests (RIT) for the diagnosis of malaria (ICT Malaria P.f/P.v and OptiMal. At the time they were tested, each of these children had been targeted for antimalarial treatment (following the IMCI strategy) because of fever and/or pallor. Only 70% of the 395 children classified to receive antimalarial drugs by the IMCI algorithm had malarial parasitaemias (68.4% had Plasmodium falciparum trophozoites, 1.3% only P. falciparum gametocytes, 0.3% P. ovale and 0.3% P. malariae). As indicators of P. falciparum trophozoites in the peripheral blood, fever had a sensitivity of 93.0% and a specificity of 15.5% whereas pallor had a sensitivity of 72.2% and a specificity of 50.8%. The RIT both had very high corresponding sensitivities (of 100.0% for the ICT and 94.0% for OptiMal) but the specificity of the ICT (74.0%) was significantly lower than that for OptiMal (100.0%). Fever and pallor were significantly associated with the P. falciparum asexual parasitaemias that equalled or exceeded the threshold intensity (2000/microl) that has the optimum sensitivity and specificity for the definition of a malarial episode. Diagnostic likelihood ratios (DLR) showed that a positive result in the OptiMal test (DLR = infinity) was a better indication of malaria than a positive result in the ICT (DLR = 3.85). In fact, OptiMal had diagnostic reliability (0.93) which approached that of an ideal test and, since it only detects live parasites, OptiMal is superior to the ICT in monitoring therapeutic responses. Although the RIT may seem attractive for use in primary health facilities because relatively inexperienced staff can perform them, the high cost of these tests is prohibitive. In holo-endemic areas, use of RIT or microscopical examination of bloodsmears may only be relevant when malaria needs to be excluded as a cause of illness (e.g. prior to treatment with toxic or expensive drugs, or during malaria epidemics). Wherever the effective drugs for the first-line treatment of malaria are cheap (e.g. chloroquine and Fansidar), treatment based on clinical diagnosis alone should prove cost-saving in health facilities without microscopy.  相似文献   

4.
OBJECTIVE: To identify clinical predictors for malaria and develop a clinical algorithm to more accurately identify malaria from non-malaria cases. METHODS: Four hundred thirty eight children aged 6-120 months attending the rural health center between August 15 and October 5, 1997, in Jhangara town of district Dadu, Sindh were recruited. A standard questionnaire was used to record symptoms and duration of child's illness. Each child was physically examined, had their axillary temperature measured, and blood samples were collected from which Giemsa stained thick and thin blood films were prepared and examined for presence of Plasmodium parasites. The sensitivity and specificity of several candidate algorithms for parasitemia were evaluated using various combinations of identified predictors. RESULTS: Twenty-six of 438 children (6%) were slide positive for malaria. An algorithm comprised of fever 3 days duration and (absence of cough or having rigors) had 100% sensitivity and 63% specificity for detecting P. falciparum. CONCLUSION: In this low malaria prevalence region, restricting the diagnosis of malaria to persons who had >3 days of fever and absence of cough or rigors, remained highly sensitive but was more specific than current practice. If validated prospectively, this algorithm could reduce misdiagnosis and mis-treatment.  相似文献   

5.
BACKGROUND: Diagnosing tuberculosis (TB) in a human immunodeficiency virus (HIV)-endemic area is extremely difficult, as the clinical symptoms of HIV-seropositive children can be easily confounded with TB. The paediatric tuberculosis score chart (TSC) was developed for resource-poor countries and its use continues to be promoted despite the fact that this scoring system has not been evaluated in countries with a high HIV prevalence. OBJECTIVE: To assess the utility of the TSC in an HIV-endemic area. METHOD: A prospective cohort study conducted between January and December 1999 at St Theresa's Mission Hospital, Copperbelt Province, Zambia. Results of the TSC (TB score) were compared with the results of a diagnostic algorithm, incorporating sputum smear microscopy, culture and polymerase chain reaction of Mycobacterium tuberculosis, tuberculin skin test, chest X-ray and histology eventually. RESULTS: A total of 147 children were enrolled in the study. On the basis of HIV-serology and clinical findings they were divided into four groups: children with TB (23 HIV-seropositive; 52 HIV-seronegative), 21 HIV-infected children without TB and 51 HIV-seronegative children without TB. The differences in TB scores between the groups were not significant. The sensitivity of the TSC to diagnose TB in this study was 88%; but the specificity was only 25%. CONCLUSION: The TSC should not be used as a diagnostic tool in countries with a high HIV prevalence. The low specificity of this scoring system leads to overdiagnosis of TB and unnecessary use of costly, antituberculous drugs. New tools for TB diagnosis in children in HIV-endemic areas are urgently needed.  相似文献   

6.
We conducted a study to determine whether clinical algorithms would be useful in malaria diagnosis among people living in an area of moderate malaria transmission within Kilifi District in Kenya. A total of 1602 people of all age groups participated. We took smears and recorded clinical signs and symptoms (prompted or spontaneous) of all those presenting to the study clinic with a history of fever. A malaria case was defined as a person presenting to the clinic with a history of fever and concurrent parasitaemia. A set of clinical signs and symptoms (algorithms) with the highest sensitivity and specificity for diagnosing a malaria case was selected for the age groups /=15 years. These age-optimized derived algorithms were able to identify about 66% of the cases among those <15 years of age but only 23% of cases among adults. Were these algorithms to be used as a basis for a decision on treatment among those presenting to the clinic, 16% of children /=5000 parasites/microl of blood would be sent home without treatment. Clinical algorithms therefore appear to have little utility in malaria diagnosis, performing even worse in the older age groups, where avoiding unnecessary use of anti-malarials would make more drugs available to the really needy population of children under 5 years of age.  相似文献   

7.
The measurement of parasite lactate dehydrogenase (pLDH) has been presented as an easy and rapid method for the diagnosis of malaria in humans. In order to evaluate the sensitivity and specificity of such a test we examined blood samples from 429 Ugandan patients. While pLDH activity was significantly linked to parasitaemia, sensitivity and specificity were found to be rather low at 58.8 and 62.2% respectively. The positive and negative predictive values failed to meet necessary standards. We conclude that the methods of measurement of pLDH activity in malaria infection, although potentially useful for the fast diagnosis of malaria, need to be improved to be of true value in endemic areas.  相似文献   

8.
Objectives Cryptococcal meningitis (CM) and tuberculous meningitis (TBM) are common in HIV‐infected adults in Africa and difficult to diagnose. Inaccurate diagnosis results in adverse outcomes. We describe patterns of meningitis in a Malawian hospital, focusing on features which differentiate CM and TBM with the aim to derive an algorithm using only clinical and basic laboratory data available in this resource‐poor setting. Methods Consecutive patients admitted with meningitis were prospectively recruited, clinical features were recorded and cerebrospinal fluid (CSF) was examined. Results A total of 573 patients were recruited, and 263 (46%) had CSF consistent with meningitis. One hundred and twelve (43%) had CM and 46 (18%) had TBM. CM was associated with high CSF opening pressure and low CSF leukocyte count. Fever, neck stiffness and reduced conscious level were associated with TBM. A diagnostic index was constructed demonstrating sensitivity 83%and specificity 79% for the differentiation of CM and TBM. An algorithm was derived with 92% sensitivity for the diagnosis of CM, but only 58% specificity. Conclusions Although we demonstrate features associated with CM and TBM, a sufficiently sensitive and specific diagnostic algorithm could not be derived, suggesting that the diagnosis of CM and TBM in resource‐limited settings still requires better access to laboratory tools.  相似文献   

9.
Loop-mediated isothermal amplification (LAMP) is a novel technique that rapidly amplifies target DNA in isothermal conditions. In a previous study, the sensitivities and specificities of LAMP, microscopy, and nested PCR were compared in the context of rapid malaria detection. In the present study, LAMP detected vivax malaria parasites in 115 of 117 microscopically positive samples (sensitivity, 98.3%; 95% CI, 97.4-100%), which agreed well with the nested PCR results (sensitivity, 99.1%; 95% CI: 96.0-100%). No positive cases of malaria were detected by LAMP or nested PCR in 50 consecutive feverish patients other than malaria from malaria endemic areas. LAMP performed on DNA extracted from heat-treated blood had a sensitivity of 93.3% (28/30, 95% CI: 84.4-100%) and specificity of 100% (30/30, 95% CI: 100%). The present study shows that LAMP based assays have high sensitivity, specificity, and amplification efficiencies for Plasmodium vivax detection. The authors recommend that LAMP can be considered as a rapid nucleic acid amplification assay for the molecular diagnosis of P. vivax in both clinical laboratories and malaria clinics in areas where vivax malaria is endemic.  相似文献   

10.
11.
Malaria control continues to rely on the diagnosis and prompt treatment of both suspected and confirmed cases through the health care structures. In south-eastern Tanzania malaria is one of the leading causes of morbidity and mortality. The absence of microscopic examination in most of the health facilities implies that health workers must rely on clinical suspicion to identify the need of treatment for malaria. Of 1558 randomly selected paediatric consultations at peripheral health facilities throughout Kilombero District, 41.1% were diagnosed by the attending health worker as clinical malaria cases and 42.5% prescribed an antimalarial. According to our malaria case definition of fever or history of fever with asexual falciparum parasitaemia of any density, 25.5% of all children attending the health services had malaria. This yielded a sensitivity of 70.4% (IC95% = 65.9-74.8%) and a specificity of 68.9% (IC95% = 66.2-71.5%). Accordingly, 30.4% of confirmed cases left with no antimalarial treatment. Among malaria-diagnosed patients, 10% were underdosed and 10.5% were overdosed. In this area, as in many African rural areas, the low diagnostic accuracy may imply that the burden of malaria cases may be overestimated. Greater emphasis on the functioning and quality of basic health services in rural endemic areas is required if improved case management of malaria is to help roll back this scourge.  相似文献   

12.
Malaria rapid diagnostic tests (RDTs) may improve fever management in areas without microscopy. We compared the accuracy of histidine-rich protein 2 (HRP2) and Plasmodium lactate dehydrogenase (pLDH)-based RDTs, using expert microscopy as a gold standard, for initial diagnosis, treatment monitoring, and diagnosis of recurrent malaria in a cohort of children followed longitudinally in a high-transmission area in Uganda. For 305 initial fever episodes, sensitivity was 98% for HRP2 and 87% for pLDH, whereas specificity was 55% and 96%, respectively. The HRP2 gave 51% false-positive results on Day 28, whereas pLDH gave no false positives after Day 7. For 59 recurrent fever episodes during follow-up, sensitivity was 100% for HRP2 and 91% for pLDH, whereas specificity was 33% and 100%, respectively. The HRP2-based RDTs are useful for initial diagnosis of malaria caused by superior sensitivity; however, as a result of superior specificity, pLDH-based RDTs are more appropriate to monitor treatment and diagnose recurrent malaria.  相似文献   

13.
BACKGROUND: Modelling malaria parasitaemia as function of fever has been proposed as best alternative to estimate the attributable fraction of malaria fever and the sensitivity and specificity of different case definitions of malaria disease. OBJECTIVES: To determine the prevalence of fever and its relation to malaria parasitaemia and to establish a pyrogenic threshold for malaria disease in the area. METHODS: We conducted two cross-sectional surveys in children of 6 months to 9 years of age (2434 during the rainy season of 1993 and 2353 during the dry season of 1994) randomly selected from 21 areas of Bandiagara district, Mali. RESULTS: The relationship between fever and Plasmodium falciparum parasitaemia depends strongly on the season, thus affecting the malaria-attributable fraction of fever cases and the sensitivity and specificity of malaria case definitions. The overall proportion of fever attributable to malaria parasitaemia was 33.6% during the rainy season and 23.3% during the dry season, with the highest proportion occurring among the youngest children. The cut-off value, where the sensitivity curve crosses the specificity curve, was around 3200 pf/microl for all age categories during the rainy season and 200 pf/microl during the dry season. CONCLUSIONS: Malaria remains a main cause of fever in this area of Mali. The pyrogenic threshold of parasitaemia depends strongly on the season, and different cut-off levels of parasitaemia should be used during the two seasons to define malaria cases in this area.  相似文献   

14.
OBJECTIVES: The performance of a new indigenous rapid diagnostic test, Paracheck Pf was evaluated in detection of Plasmodium falciparum in asymptomatic children in remote forest villages of Mandla district, central India to determine the lower limits of sensitivity and specificity of rapid test. METHODS: A finger prick blood sample was collected to prepare blood smear and for testing with the Paracheck test. The blood smears were read by an experienced technician blinded to the Paracheck results. The figures for specificity, sensitivity, accuracy and predictive values were calculated using microscopy as gold standard. RESULTS: The new diagnostic test had a sensitivity of 94% and a specificity of 89%. The positive and negative predictive values were 71% and 98%, respectively. The J -index was 0.83%. CONCLUSION: The rapid test was found to be very easy to perform and the result could be read reliably by field workers. The field evaluation with this new inexpensive test, ($0.65/test) indicates that it could be used as an epidemiological tool in the management of malaria particularly in areas where microscopy is not operationally feasible to attain the goal of the roll back malaria initiative.  相似文献   

15.
Under the current guidelines of presumptive treatment of all children with reported fever, the risk of over-prescribing antimalarial drugs and missing other important causes of fever, like acute respiratory tract infection (ARI), is substantial. Clinical algorithms have been shown to be useful in diagnosing malaria, but often with differing results, due to regional variations. We set out to explore the clinical features associated with malaria compared with other febrile illnesses and specifically severe malaria with ARI in children under five in Pemba. Two hundred and seven children aged six months to five years presenting to a hospital clinic with fever were studied in Pemba. Clinical findings were related to the presence of malaria parasitaemia. Malaria accounted for 67.7% of the febrile episodes investigated. Five symptoms and signs, including pallor, drowsiness, splenomegaly, fever duration and no chest crackles, could accurately predict a case of malaria with a sensitivity of 91.3% and specificity of 53% and positive predictive value of 80.3%. Several clinical features were found to differentiate severe malaria from ARI. These results confirm that clinical algorithms can increase the diagnostic accuracy of malaria, although not sufficiently to replace microscopy, and by promoting the use of clinical skills other treatable causes of febrile illnesses may be identified.These findings could have implications in optimizing treatment and malaria control in children on Pemba.  相似文献   

16.
Early diagnosis of malaria followed by appropriate treatment can help reduce related morbidity and mortality as well as interrupt transmission. Previous studies of household responses to malaria have tended to focus on endemic areas where the burden of this disease is greatest. With the apparent increasing frequency of epidemics in African highlands, a better understanding of treatment behaviours in areas of unstable transmission may be important to future public health interventions. This study was undertaken following a serious epidemic of malaria in the highlands of south-western Uganda. Our objectives were to characterize actions taken by both adults and caretakers of children < or =5 years old during their most recent episode of self-diagnosed malaria, and to identify factors that were associated with prompt treatment at a health facility. A survey of 300 households selected in a 2-stage cluster sampling procedure produced 453 adult respondents and 133 caretakers of children < or =5 years old. We found that almost 65% of adults and 62% of children who had experienced an episode of malaria in the last year (most during the epidemic) had sought treatment from a health facility first as opposed to self-treatment. Most of these people had visited the health facility within 1 day of symptom onset. By the end of their malaria episode, over 87% of adults and 80% of children had visited a health facility at least once. Factors associated with prompt presentation at a health facility included severity of illness, household proximity to a health facility, and knowledge of malaria prevention methods. Our results indicate that there is an important role for the formal health care system in mitigating morbidity and mortality and reducing transmission during malaria epidemics in Uganda.  相似文献   

17.

Background

Plasmodium falciparum malaria, is a major health problem in forested tribal belt of central India. Rapid and accurate methods are needed for the diagnosis of P. falciparum. We performed a blinded evaluation of the recently introduced Determine? malaria pf test (Abbott, Laboratories, Japan) compared with microscopy and splenomegaly in children in epidemic prone areas of district Mandla to assess the impact of intervention measures.

Methods

Children aged 2–10 yrs with and without fever were examined for spleen enlargement by medical specialist by establishing a mobile field clinic. From these children thick blood smears were prepared from finger prick and read by a technician. Simultaneously, rapid tests were performed by a field lab attendant. The figures for specificity, sensitivity and predictive values were calculated using microscopy as gold standard.

Results

In all 349 children were examined. The sensitivity and specificity for Determine rapid diagnostic test were 91 and 80% respectively. The positive predictive values (PPV), negative predictive values (NPV) and accuracy of the test were respectively 79, 91 and 85%. On the contrary, the sensitivity and specificity of spleen in detecting malaria infection were 57 and 74 % respectively with PPV of 73%, NPV 59 % and an accuracy of 65%.

Conclusions

Determine? malaria rapid diagnostic test is easier and quicker to perform and has other advantages over microscopy in not requiring prior training of personnel or quality control. Thus, highlighting the usefulness of a rapid antigen test in assessing prevailing malaria situation in remote areas.  相似文献   

18.
The immunochromatographic tests with HRP-2 antigen (histidine-rich protein) Vision Biotech Pf Rapid Malaria Test was performed in 291 children under 5 years presenting fever or history of fever (malaria presumptive cases) admitted to Children Out-Patient Department of the Modilon Hospital in Madang, in a high malaria risk area of Papua New Guinea. The results of the tests were compared to the results of the parasitic examination of the peripheral blood with light microscopy (thick and thin smears). The HRP-2 test showed very high sensitivity (95.4%) and specificity (94.1%) for Plasmodiumfalciparum parasitaemia and none or very low sensitivity and specificity for other malaria species. The HRP-2 test detected both asexual and sexual stages of the Plasmodium falciparum parasites. The test did not show significant changes in detection of different levels of parasitaemia. These findings enable to conclude that the HRP-2 immunochromatographic assay can be very helpful to diagnose Plasmodium falciparum malaria when microscopy examination is not available, but as qualitative tests can be difficult for interpretation especially in high malaria risk areas. Therefore it can require re-examination of blood with microscopy to confirm species and development stages of Plasmodium spp. and to assess parasite load.  相似文献   

19.
OBJECTIVES: The Integrated Management of Childhood Illness (IMCI) approach and new clinical treatment guidelines to control malaria among children less than 5 years old were introduced recently in Cambodia. This study was conducted to finalize the malaria part of the national IMCI fever chart. METHODS: A total of 323 sick children 2-59 months old were studied at rural health centres in northern Cambodia from February to April 2000. Cases with fever (by axillary temperature or history) or anaemia (by palmar pallor) were tested with dipsticks for Plasmodium falciparum and Plasmodium vivax in high and low malaria risk areas and, if positive, treated with anti-malarials. RESULTS: The draft IMCI chart identified children with malaria safely and effectively (sensitivity 14 of 15, approximately 93% and specificity 292 of 308, approximately 95%). The study confirmed the potential of malaria dipsticks as a part of IMCI case management. CONCLUSION: The Cambodian Ministry of Health will use the studied malaria chart during the Early Implementation Phase of IMCI. Dipsticks able to detect P. falciparum and P. vivax with high sensitivity and acceptable cost will be needed for this purpose. To promote the rational use of dipsticks, the National Centre for Malaria Control, Parasitology and Entomology (Centre National de Malaridogie, Parasitologie et Entomologie, CNM) should list all known malaria risk areas in the country and prepare detailed local maps guiding case management especially in transitional zones.  相似文献   

20.
210 children aged less than 5 years, referred to the Arua Regional TB Centre (Uganda) for suspected pulmonary tuberculosis (PTB), were examined by anamnesis, clinical examination, Mantoux test, gastric washing, chest X-ray. The response to treatment criterion was applied to the patients treated. According to the score method suggested by Ghidey and Habte, 31 children were diagnosed as PTB patients. 30 of the 31 children with PTB tested positive for alcohol acid-fast bacilli (AAFB) in the aspirated juice. The Mantoux test and X-rays gave a minor contribution to diagnosis. The clinical results are commented. A statistical analysis was carried out to evaluate the role of gastric washing in the diagnosis of PTB in children under 5 years of age (sensitivity, 96.8%; specificity, 92.2%; positive predictive value, 68.2%; negative predictive value, 99.4%). The response to treatment was also evaluated. A modified enlarged score method (based on gastric washing and including response to treatment) is proposed to be applied in developing countries where chest X-ray and other facilities are often lacking.  相似文献   

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