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Most Human African Trypanosomiasis (HAT) control programmes in areas endemic for Trypanosoma brucei gambiense rely on a strategy of active mass screening with the Card Agglutination Test for Trypanosomiasis (CATT)/T. b. gambiense. We evaluated the performance, stability and reproducibility of the CATT/T. b. gambiense on blood-impregnated filter papers (CATT-FP) in Kajo-Keji County, South-Sudan, where some areas are inaccessible to mobile teams. The CATT-FP was performed with a group of 100 people with a positive CATT on whole blood including 17 confirmed HAT patients and the results were compared with the CATT on plasma (CATT-P). The CATT-FP was repeated on impregnated filter papers stored at ambient and refrigerated temperature for 1, 3, 7 and 14 days. Another 82 patients with HAT, including 78 with a positive parasitology, were tested with the CATT-FP and duplicate filter paper samples were sent to a reference laboratory to assess reproducibility. The CATT-FP was positive in 90 of 99 patients with HAT (sensitivity: 91%). It was less sensitive than the CATT-P (mean dilution difference: -2.5). There was no significant loss of sensitivity after storage for up to 14 days both at ambient and cool temperature. Reproducibility of the CATT-FP was found to be excellent (kappa: 0.84). The CATT-FP can therefore be recommended as a screening test for HAT in areas where the use of CATT-P is not possible. Further studies on larger population samples in different endemic foci are still needed before the CATT-FP can be recommended for universal use. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Medicine & International Health is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: To compare two separately funded, but operationally similar, residual household-spraying (RHS) initiatives; one rural and one peri-urban in southern Mozambique.Methods: The rural programme is a regional project involving the participation and co-ordination of organizations across three countries in southern Africa and is focussed on control in an area in Mozambique of 7552 km2. The second programme focuses on spraying a peri-urban community within a 10-km radius around MOZAL, an aluminium smelter plant of area 410 km2. An ingredients approach was used to derive unit costs for both the rural and peri-urban spraying programmes using detail retrospective cost data and effectiveness indicators.Results: The economic cost per person covered per year using Carbamates for indoor residual spraying (IRS) in the rural area, excluding the costs of project management and monitoring and surveillance was $3.48 and in the peri-urban area, $2.16. The financial costs per person covered in the rural area and peri-urban area per year were $3.86 and $2.41, respectively. The economic costs per person covered were respectively increased by 39% and 31% when project management and monitoring and surveillance were included. The main driving forces behind the costs of delivering RHS are twofold: the population covered and insecticide used. Computed economic and financial costs are presented for all four insecticide families available for use in RHS.Conclusions: The results from both these initiatives, especially the rural area, should be interpreted as conservative cost estimates as they exclude the additional health gains that the newly introduced programmes have had on malaria rates in the neighbouring areas of South Africa and Swaziland. Both these initiatives show that introducing an IRS programme can deliver a reduction in malaria-related suffering providing financial support, political will, collaborative management and training and community involvement are in place. [ABSTRACT FROM AUTHOR]

The incidence of the American visceral leishmaniasis (AVL) in the Island of Margarita, a major tourist centre in Venezuela, has been increasing between 1998 and 2001. Lutzomyia longipalpis s.l. is the recognized vector, which was found naturally infected with Leishmania spp, indistinguishable from the parasites recovered from dogs and children. In 1999-2000, we conducted a control trial in Santa Ana del Valle and Las Cabreras, which have similar epidemiological and ecological conditions. The trial was based on intradomestic residual spraying of lambda-cyhalothrin, E.C., 25 mg/m2 and spatial fogging of fenitrothion around the houses at 30 g/ha. Sandfly abundance was recorded using Centers for Disease Control (CDC) traps indoors and outdoors. We found significantly reduced sandfly populations in the target locality. Wall bioassays showed that the residual effect of the insecticide lasts for about 3 months. We believe that indoor spraying with lambda-cyhalothrin three times a year, at a dose slightly greater than 25 mg/m2, might reduce the L. longipalpis s.l. population to a level low enough for achieving a significant reduction of the indoor transmission, thus protecting small children from the disease. [ABSTRACT FROM AUTHOR]

Levels of drug resistance of Plasmodium falciparum strains against antimalarials have increased in Laos. In several studies, chloroquine (CQ) resistance has been associated with point mutations in the Pfcrt and pfmdr genes, and sulphadoxine/pyrimethamine (S/P) resistance with point mutations in the genes of dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS). We combined a study of these molecular markers with an in vivo antimalarial drug sensitivity study in Attapeu province in the south of Lao PDR. We treated 100 patients with either CQ, S/P or a combination of both. In the CQ group, Pfcrt mutations showed a very high sensitivity (100%) but a low specificity (12.5%) to predict resistance. The combination of mutations in the Pfcrt and pfmdr genes was highly specific and had a positive predictive value of 100%. Mutations in the DHPS gene showed a high correlation with the development of resistance. The prevalence of mutations in the DHFR gene, especially codon 108 Asn, was predictive with high sensitivity (100%) but low specificity. Isolates derived from patients treated with a combination of both drugs showed a high correlation between the mutation in codon 437 of DHPS gene and in vivo-resistance (odds ratio 16.00, CI). The study provides evidence for the existence of antimalarial drug resistance in the south of Lao PDR, and offers a molecular method to predict resistance. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the strengths and weaknesses of the indicators 'proportion of households possessing mosquito net(s)' and 'proportion of children under 5 years of age who slept under a net the preceding night' for monitoring malaria control.Methods: Review of data from household surveys including demographic and health surveys in sub-Saharan African countries.Results: Net possession ranged among 14 surveyed regions from 0.1% to 28.5% for insecticide-treated nets (ITNs) and among 69 regions from 3.6% to 79.7% for any net. Reported use during the preceding night by children under 5 years of age was between 0% and 16% for ITNs and between 0.7% and 74.5% for any net. On average, in households owning ITN(s), 55% of children slept under it (R2 = 0.97, P < 0.001). For any net, use was -4.2% + 0.875 x possession (R2 = 0.89, P < 0.001); the use of nets, however, also varied somewhat among the surveyed countries (P = 0.003). In-depth surveys suggested that use was lower than possession because: (i). nets were scarce (mean 1.8 per possessing household); (ii). nets were not always used for children and (iii). use was lower during hot, dry months than during cool rainy months, and many surveys had been conducted in the dry season.Conclusions: Not all mosquito nets owned by African households are being used for young children. Household education on the consistent use of nets for this vulnerable group is called for in malaria control programmes. Regular, district-level rapid assessments of household possession of nets should complement ongoing in-depth surveys. Data on 'use during the preceding night' must be interpreted taking the survey season into account. [ABSTRACT FROM AUTHOR]

Chloroquine (CQ) resistance was first documented in Uganda in 1988. Subsequent surveillance of antimalarial drug resistance, conducted by the Ugandan Ministry of Health and several research organizations, suggests that resistance to CQ is now widespread, reaching critical levels in many areas of the country. In June 2000, the Ministry of Health held a National Consensus Meeting to evaluate the available drug efficacy data and review the national antimalarial drug policy. After extensive debate, the combination of CQ + sulfadoxine-pyrimethamine (SP) was chosen to replace CQ as the first-line treatment of uncomplicated malaria as an interim policy. This review evaluates the in vivo drug efficacy studies conducted in Uganda since 1988 and issues confronted in revision of the drug policy. The Ugandan experience illustrates the challenges faced by sub-Saharan African countries confronted with rising CQ resistance but limited data on potential alternative options. The choice of CQ + SP as a provisional policy in the absence of prerequisite efficacy, safety and cost-effectiveness data reflects the urgency of the malaria treatment problem, and growing pressure to adopt combination therapies. Surveillance of CQ + SP treatment efficacy, collection of additional data on alternative regimens and active consensus building among key partners in the malaria community will be necessary to develop a rational long-term antimalarial treatment policy in Uganda. [ABSTRACT FROM AUTHOR]

In malaria endemic areas anaemia is a usually silent condition that nevertheless places a considerable burden on health services. Cases of severe anaemia often require hospitalization and blood transfusions. The objective of this study was to assess risk factors for admission with anaemia to facilitate the design of anaemia control programmes. We conducted a prospective case-control study of children aged 2-59 months admitted to a district hospital in southern Tanzania. There were 216 cases of severe anaemia [packed cell volume (PCV) < 25%] and 234 age-matched controls (PCV > or = 25%). Most cases [55.6% (n = 120)] were < 1 year of age. Anaemia was significantly associated with the educational level of parents, type of accommodation, health-seeking behaviour, the child's nutritional status and recent and current medical history. Of these, the single most important factor was Plasmodium falciparum parasitaemia [OR 4.3, 95% confidence interval (CI) 2.9-6.5, P < 0.001]. Multivariate analysis showed that increased recent health expenditure [OR 2.2 (95% CI 1.3-3.9), P = 0.005], malnutrition [OR 2.4 (95%CI 1.3-4.3), P < 0.001], living > 10 km from the hospital [OR 3.0 (95% CI 1.9-4.9), P < 0.001], a history of previous blood transfusion [OR 3.8 (95% CI 1.7-9.1), P < 0.001] and P. falciparum parasitaemia [OR 9.5 (95% CI 4.3-21.3), P < 0.001] were independently related to risk of being admitted with anaemia. These findings are considered in terms of the pathophysiological pathway leading to anaemia. The concentration of anaemia in infants and problems of access to health services and adequate case management underline the need for targeted preventive strategies for anaemia control. [ABSTRACT FROM AUTHOR]

We developed a polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) for the detection of Onchocerca volvulus DNA. To standardize the PCR and to avoid false-negative results, an internal control DNA was co-amplified by the same set of primers. We differentiated the wild-type PCR product of the O-150 DNA sequence from the internal control by specific DNA probes. Detection of biotinylated PCR products by DNA probes was performed by ELISA to quantify the PCR product or by DNA Detection Test Strips as a rapid field technique. The methods were evaluated on skin biopsies from individuals living in an area endemic for O. volvulus in Uganda, but with low microfilaria densities because of ivermectin treatment. Microfilaria density was assessed by a single skin snip and a second skin snip was examined by PCR. Among 69 samples from microfilaria carriers, 47 (68%) were positive by ELISA and 55 (80%) by test strip detection of PCR products. When 39 samples of microfilaria-negative individuals from the same area were tested, 10 (27%) were positive by ELISA and 12 (31%) by test strips. None of the 19 samples obtained from persons living in an area not endemic for O. volvulus but endemic for Mansonella streptocerca was positive in either test. Although the ELISA is theoretically more sensitive than the test strips for the detection of PCR products, examination of field samples revealed that the test strip method had a higher operational sensitivity and was more convenient to perform. Thus, the DNA Detection Test Strips are a rapid and low-tech tool for identification of PCR products in laboratories of countries endemic for onchocerciasis. [ABSTRACT FROM AUTHOR]

We present evidence for the putative role of Rhodnius robustus as extradomestic vector of Chagas disease in Western Venezuela. First, we assessed the validity of this triatomine species by genetic characterization in relation with some other species of the prolixus group. Random amplified polymorphic DNA data showed a clear separation between this species and R. prolixus and indicated a probable genetic heterogeneity within R. robustus. Faeces and gut contents were microscopically examined in 54 of 137 R. robustus collected in palm trees. According to this morphological examination, 18% were positive for Trypanosoma cruzi, 11% harboured T. rangeli and 11% showed mixed infection. Five of the seven samples examined gave a polymerase chain reaction major band of 270 bp specific of T. cruzi. The hybridization probes showed that R. robustus may transmit clones 20 and 39 (or genetically related ones) in Venezuela. Such a transmission might occur when, in absence of domestic R. prolixus and attracted by artificial light, R. robustus enters houses and feeds on humans, or when people are bitten outdoors. The lack of bugs inside houses could mean that the insects leave houses after feeding, or die without reproducing there. [ABSTRACT FROM AUTHOR]

The protein Ov20/OvS1 was used as antigen in ELISA and Western blot in order to differentiate onchocerciasis from African mansonelliasis and to characterize the hyperreactive form of Onchocerca volvulus infection (sowda). The specificity of the IgG4 Western blot was 98% for the differentiation between persons with onchocerciasis and Mansonella microfilariae (mf) carriers (125 persons with M. perstans and 92 with M. streptocerca), whereas the IgG4 ELISA showed a specificity of 81% in 137 M. perstans mf carriers and 85% in 94 M. streptocerca mf carriers. The sensitivity of Ov20/OvS1 in identifying onchocerciasis using the IgG4 ELISA was 75% for 103 O. volvulus mf carriers with the generalized and 89% for 44 patients with the sowda form of onchocerciasis. IgE antibodies against OvS1 were found in 95% of 39 patients with hyperreactive onchocerciasis but only in 15% of 47 persons with the generalized form. Thus, Ov20/-OvS1 appears a promising candidate antigen for the diagnosis of onchocerciasis and in particular for the detection of the sowda type of disease. [ABSTRACT FROM AUTHOR]

Chemotherapy with praziquantel is the cornerstone of schistosomiasis control. In view of recent concern about tolerance or resistance to praziquantel, monitoring its efficacy in different epidemiological settings is required. We report a study among 253 schoolchildren in an area highly endemic for Schistosoma mansoni in western Côte d'Ivoire. After examining four consecutive stool specimens from each child, the first praziquantel treatment at 60 mg/kg divided into two doses was administered. Four weeks later, stool specimens were again screened over 4 consecutive days and revealed a cure rate of 71.6% and an egg reduction rate of 79.9%. There was a significant association between cure rate and intensity of infection prior to treatment with highest cure rates observed in light infections (P < 0.01). Praziquantel, at a single dose of 40 mg/kg, was again administered 35 days after the first treatment. The overall cure and egg reduction rates increased considerably. The association between cure rate and intensity of infection prior to the second treatment was significant but less pronounced. Twenty-two children remained S. mansoni positive after the two chemotherapy campaigns, and interestingly, many of these were only identified after repeated stool examinations. We argue that pre-patent infections may account for some of these 'treatment failures'. However, further studies in other endemic settings are needed, with parasitological diagnoses having a high sensitivity. [ABSTRACT FROM AUTHOR]

The commercially available ICT Card Test for bancroftian filariasis was evaluated for its sensitivity and specificity in detecting microfilaria carriers among 189 individuals each in filariasis-endemic and nonendemic areas in South India, and compared to both conventional night blood finger prick thick blood smear examination and venous blood membrane filtration. Though the specificity of the test was 100% in comparison to both, the sensitivity was 98.5% against the finger prick thick blood smear and 71.9 compared to the membrane filtration technique. Similarly, the positive predictive value was 100% against both techniques, but the negative predictive values were 99.5% against the finger prick thick blood smear and 88.3% compared to the membrane filtration technique. The test's lower sensitivity compared to the filtration technique requires further investigation. [ABSTRACT FROM AUTHOR]

Objective: To evaluate an immunofluorescence antibody test (IFAT) for diagnosis of schistosomiasis in nonimmune travellers and immigrants from endemic areas.Methods: 65 patients (48 Danes and 17 immigrants) with schistosomiasis were included. The diagnosis of schistosomiasis was based on the presence of schistosome eggs in faeces, urine, sperm, rectal or bladder biopsies and/or the presence of specific antibodies determined by the serological immunofluorescence antibody test (IFAT). Egg excretion was detected using conventional methods and the IFAT performed on whole S. mansoni schistosomula worms, harvested after 8 weeks from mice. Two patterns of immunofluorescence were observed: Fluorescence in the gut of the schistosome called 'Gut Associated Antigen, GAA', and fluorescence of the surface of the schistosomula called 'Membrane Bound Antigen, MBA'.Results: Eggs were found in 44% of the Danish patients and in 76% of immigrants. The diagnosis was based on a positive IFAT in 48% of the patients. In patients from nonendemic areas, the finding of antibodies against GAA was diagnostic while optimal sensitivity in the immigrants was reached by measuring antibodies against both GAA and MBA.Conclusion: In patients from nonendemic areas GAA is a sensitive marker of acute infection with schistosomiasis. In patients from endemic areas the demonstration of both GAA and MBA is necessary to properly identify long-lasting, nonacute infections. Egg-detection and/or measurement of CAA and CCA remain the methods of choice to monitor treatment as the immunofluorescence assay may remain positive for several years after treatment. [ABSTRACT FROM AUTHOR]