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Self-reported serious illnesses in rural Cambodia: a cross-sectional survey
No full textBACKGROUND: There is substantial evidence that ill-health is a major cause of impoverishment in developing countries. Major illnesses can have a serious economic impact on poor households through treatment costs and income loss. However, available methods for measuring the impact of ill-health on household welfare display several shortcomings and new methods are thus needed. To understand the potential complex impact of major illnesses on household livelihoods, a study on poverty and illness was conducted in rural Cambodia, as part of an international comparative research project. A cross-sectional survey was performed to identify households affected by major illness for further in-depth interviews. METHODOLOGY AND PRINCIPAL FINDINGS: 5,975 households in three rural health districts were randomly selected through a two-stage cluster sampling and interviewed. 27% of the households reported at least one member with a serious illness in the year preceding the survey and 15% of the household members reported suffering from at least one serious illness. The most reported conditions include common tropical infectious diseases, chronic diseases (notably hypertension and heart diseases) and road traffic accidents. Such conditions were particularly concentrated among the poor, children under five, women, and the elderly. Poor women often reported complications related to pregnancy and delivery as serious illnesses. CONCLUSIONS AND SIGNIFICANCE: Despite some methodological limitations, this study provides new information on the frequency of self-reported serious illnesses among the rural Cambodia's population, which serves as a basis for further in-depth investigation on 'major illnesses' and their economic consequences on poor households. This can in turn help policy makers to formulate appropriate interventions to protect the poor from the financial burden associated with ill-health. Our findings suggest that every year a considerable proportion of rural population in Cambodia, especially the poor and vulnerable, are affected by serious illnesses, both communicable and non-communicable disease
Multilocus genotyping reveals high heterogeneity and strong local population structure of the Plasmodium vivax population in the Peruvian Amazon
No full textABSTRACT: BACKGROUND: Peru is one of the Latin American countries with the highest malaria burden, mainly due to Plasmodium vivax infections. However, little is known about P. vivax transmission dynamics in the Peruvian Amazon, where most malaria cases occur. The genetic diversity and population structure of P. vivax isolates collected in different communities around Iquitos city, the capital of the Peruvian Amazon, was determined. METHODS: Plasmodium vivax population structure was determined by multilocus genotyping with 16 microsatellites on 159 P. vivax infected blood samples (mono-infections) collected in four sites around Iquitos city. The population characteristics were assessed only in samples with monoclonal infections (n=94), and the genetic diversity was determined by calculating the expected heterozygosity and allelic richness. Both linkage disequilibrium and the genetic differentiation (theta) were estimated. RESULTS: The proportion of polyclonal infections varied substantially by site (11% - 70%), with the expected heterozygosity ranging between 0.44 and 0.69; no haplotypes were shared between the different populations. Linkage disequilibrium was present in all populations (IAS 0.14 - 0.61) but was higher in those with fewer polyclonal infections, suggesting inbreeding and a clonal population structure. Strong population differentiation (theta = 0.45) was found and the Bayesian inference cluster analysis identified six clusters based on distinctive allele frequencies. CONCLUSION: The P. vivax populations circulating in the Peruvian Amazon basin are genetically diverse, strongly differentiated and they have a low effective recombination rate. These results are in line with the low and clustered pattern of malaria transmission observed in the region around Iquitos cit
First evidence of high knockdown resistance frequency in Anopheles arabiensis (Diptera: Culicidae) from Ethiopia
No full textThe status of knockdown resistance (kdr) mutation was investigated in the major malaria vector Anopheles arabiensis Patton (Diptera: Culicidae) from Ethiopia. Among 240 mosquito samples from 15 villages of southwestern Ethiopia that were screened by allele-specific polymerase chain reaction for kdr mutations, the West African kdr mutation (L1014F) was detected in almost all specimens (98.5%), whereas the East African kdr mutation (L1014S) was absent. Moreover, the mortality of An. gambiae s.l. to diagnostic dosages of 4% DDT, 0.75% permethrin, and 0.05% deltamethrin from bioassay results was 1.0%, 18.1%, and 82.2%, respectively. We report here the highest kdr allele frequency ever observed in An. arabiensis and its implications in malaria vector control in Ethiopia are discusse
Accuracy of a rapid diagnostic test on the diagnosis of malaria infection and of malaria - attributable fever during low and high transmission season in Burkina Faso
No full textBACKGROUND: Malaria management policies currently recommend that the treatment should only be administered after laboratory confirmation. Where microscopy is not available, rapid diagnostic tests (RDTs) are the usual alternative. Conclusive evidence is still lacking on the safety of a test-based strategy for children. Moreover, no formal attempt has been made to estimate RDTs accuracy on malaria-attributable fever. This study aims at estimating the accuracy of a RDT for the diagnosis of both malaria infection and malaria - attributable fever, in a region of Burkina Faso with a typically seasonal malaria transmission pattern. METHODS: Cross-sectional study. Subjects: all patients aged > 6 months consulting during the study periods. Gold standard for the diagnosis of malaria infection was microscopy. Gold standard for malaria-attributable fever was the number of fevers attributable to malaria, estimated by comparing parasite densities of febrile versus non-febrile subjects. Exclusion criteria: severe clinical condition needing urgent care. RESULTS: In the dry season, 186/852 patients with fever (22%) and 213/1,382 patients without fever (15%) had a Plasmodium falciparum infection. In the rainy season, this proportion was 841/1,317 (64%) and 623/1,669 (37%), respectively. The attributable fraction of fever to malaria was 11% and 69%, respectively. The RDT was positive in 113/400 (28.3%) fever cases in the dry season, and in 443/650 (68.2%) in the rainy season. In the dry season, the RDT sensitivity and specificity for malaria infection were 86% and 90% respectively. In the rainy season they were 94% and 78% respectively. In the dry season, the RDT sensitivity and specificity for malaria-attributable fever were 94% and 75%, the positive predictive value (PPV) was 9% and the negative predictive value (NPV) was 99.8%. In the rainy season the test sensitivity for malaria-attributable fever was 97% and specificity was 55%. The PPV ranged from 38% for adults to 82% for infants, while the NPV ranged from 84% for infants to over 99% for adults. CONCLUSIONS: In the dry season the RDT has a low positive predictive value, but a very high negative predictive value for malaria-attributable fever. In the rainy season the negative test safely excludes malaria in adults but not in childre
Response to treatment in a prospective cohort of patients with large ulcerated lesions suspected to be Buruli Ulcer (Mycobacterium ulcerans disease)
No full textBACKGROUND: The World Health Organization (WHO) advises treatment of Mycobacterium ulcerans disease, also called "Buruli ulcer" (BU), with a combination of the antibiotics rifampicin and streptomycin (R+S), whether followed by surgery or not. In endemic areas, a clinical case definition is recommended. We evaluated the effectiveness of this strategy in a series of patients with large ulcers of > or =10 cm in longest diameter in a rural health zone of the Democratic Republic of Congo (DRC). METHODS: A cohort of 92 patients with large ulcerated lesions suspected to be BU was enrolled between October 2006 and September 2007 and treated according to WHO recommendations. The following microbiologic data were obtained: Ziehl-Neelsen (ZN) stained smear, culture and PCR. Histopathology was performed on a sub-sample. Directly observed treatment with R+S was administered daily for 12 weeks and surgery was performed after 4 weeks. Patients were followed up for two years after treatment. FINDINGS: Out of 92 treated patients, 61 tested positive for M. ulcerans by PCR. PCR negative patients had better clinical improvement than PCR positive patients after 4 weeks of antibiotics (54.8% versus 14.8%). For PCR positive patients, the outcome after 4 weeks of antibiotic treatment was related to the ZN positivity at the start. Deterioration of the ulcers was observed in 87.8% (36/41) of the ZN positive and in 12.2% (5/41) of the ZN negative patients. Deterioration due to paradoxical reaction seemed unlikely. After surgery and an additional 8 weeks of antibiotics, 98.4% of PCR positive patients and 83.3% of PCR negative patients were considered cured. The overall recurrence rate was very low (1.1%). INTERPRETATION: Positive predictive value of the WHO clinical case definition was low. Low relapse rate confirms the efficacy of antibiotics. However, the need for and the best time for surgery for large Buruli ulcers requires clarification. We recommend confirmation by ZN stain at the rural health centers, since surgical intervention without delay may be necessary on the ZN positive cases to avoid progression of the disease. PCR negative patients were most likely not BU cases. Correct diagnosis and specific management of these non-BU ulcers cases are urgently neede
Post-production losses in iodine concentration of salt hamper the control of iodine deficiency disorders: a case study in northern Ethiopia
No full textIodine is essential for good function of the thyroid, and its deficiency is of public-health importance in Ethiopia. Iodization of salt is an effective and sustainable strategy to prevent and control iodine deficiency in large populations. The effectiveness of salt-iodization programmes depends on the conservation of iodine concentration in salt at various stages of the supply-chain. The overall objective of the study was to assess the loss of iodine in salt from production to consumption and to estimate the proportion of adults, especially pregnant women, at risk of dietary iodine insufficiency. A cross-sectional study was conducted during February-April 2007 in northern Ethiopia. Iodine concentrations of salt samples from producers (n=41), retailers (n=7), and consumers (n=32) were determined using iodiometric titration. A risk assessment was conducted for dietary iodine insufficiency among adults, including pregnant women, using a semi-probabilistic approach. The concentration of iodine in the sampled salts decreased by 57% from the production site to the consumers. The assessment of exposure showed that adults in 63% (n=20) of the households, including 90% (n=29) with pregnant women, were at risk of insufficient iodine intake. A monitoring and evaluation system needs to be established to ensure adequate supply of iodine along the distribution chain. Special attention is needed for the retailers and consumers. At these levels, dissemination of information regarding proper storage and handling of iodized salt is necessary to address the reported loss of iodine from sal
Low specificities of HIV diagnostic tests caused by Trypanosoma brucei gambiense sleeping sickness
No full textBACKGROUND: Accuracy of HIV diagnostic tests in tropical infections is poorly documented. Human African trypanosomiasis (HAT) is characterized by a polyclonal B-cell activation, constituting a risk for false positive reactions in diagnostic tests, including HIV tests. METHODS: A retrospective HIV diagnostic test accuracy study was performed on 360 human African trypanosomiasis (HAT) patients infected with T.b. gambiense before treatment, and 163 patients 2 years after successful treatment in Mbuji Mayi, East Kasai, DR Congo. Sensitivity, specificity and positive predictive value (PPV) of individual tests and algorithms consisting of 3 rapid tests were determined. RESULTS: Sensitivity for all tests was 100% (11/11). Low specificity (96.3%, 335/348) and PPV (45.8%, 11/24) of a classical seroconfirmation strategy (Vironostika ELISA followed by Line Immunoassay) complicated determination of the HIV status, which had to be determined by PCR. Specificities of rapid diagnostic tests were 39.1% for Determine (136/348), 85.3-92.8% (297/348-323/348) for VIKIA, Immunoflow, Doublecheck and Bioline, and 96.6-98.3% (336/348-342/348) for UniGold, Oraquick and STAT-PAK. Specificity for Vironostika was 67.5% (235/348). PPVs ranged between 4.9 and 64.7%. Combining 3 different rapid tests resulted in specificities of 98.3-100% (342-348/348) and PPVs of 64.7-100% (11/17-11/11). In cured HAT patients, specificities were significantly higher for Vironostika, Determine, Unigold and Immunoflow. CONCLUSIONS: T.b. gambiense infection decreases the specificity of antibody detection tests for HIV diagnosis. Unless tests have been validated for interference with HAT, HIV diagnosis in untreated HAT using classical algorithms should be avoided. Specific, validated combinations of 3 HIV rapid tests can increase specificit
