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Therapy of vector-borne protozoan infections in nonendemic settings
No full textVector-borne protozoan infections are responsible for a wide variety of illnesses (mainly malaria, trypanosomiasis and leishmaniasis) affecting tropical and subtropical areas, but increasingly diagnosed in nonendemic settings. This article summarizes the therapeutic developments for these conditions during the past decade and focuses specifically on treatment recommendations for returning travelers and migrants. The treatment of malaria has known the most spectacular improvements. Progress in the management of leishmaniasis and trypanosomiasis has also been substantial and includes introduction of new drugs into clinical practice, combinations of existing drugs, or new laboratory tools for treatment monitoring as well as extension of treatment indications to new groups of patients. Serious gaps still exist in terms of effectiveness and tolerance. Since the research pipeline is very limited for the coming 5-10 years, optimized combinations of existing drugs need to be urgently explored
The effects of sampling method and vegetation type on the estimated abundance of Ixodes ricinus ticks in forests
No full textEstimating the spatial and temporal variation in tick abundance is of great economical and ecological importance. Entire-blanket dragging is the most widely used method to sample free-living ixodid ticks. However, this technique is not equally efficient in different vegetation types. The height and structure of the vegetation under study will not only determine the likelihood of a tick-blanket contact, but will also determine the rate of dislodgement. The purpose of this study was therefore to determine whether the alternative strip-blanket is more effectively in picking up ticks than the standard entire-blanket. Sampling was carried out in four forest understory vegetation types that differed in height and structure on five collection dates between April and September 2008. A total of 8,068 Ixodes ricinus ticks was collected (778 adults, 1,920 nymphs, and 5,370 larvae). The highest numbers of ticks were collected along the forest trails, where the dominant vegetation consisted of short grasses. The lowest numbers of ticks were collected in bracken-fern-dominated sites, where the vegetation seriously hampered tick sampling. Surprisingly, in each vegetation type, significantly more nymphs and adults were collected using the entire-blanket. However, the strip-blanket was more effectively in collecting larvae, especially in dense and tall vegetation
The contribution of water contact behavior to the high Schistosoma mansoni infection rates observed in the Senegal River basin
No full textBACKGROUND: Schistosomiasis is one of the major parasitic diseases in the world in terms of people infected and those at risk. Infection occurs through contact with water contaminated with larval forms of the parasite, which are released by freshwater snails and then penetrate the skin of people. Schistosomiasis infection and human water contact are thus essentially linked, and more knowledge about their relationship will help us to develop appropriate control measures. So far, only few studies have related water contact patterns to infection levels. METHODS: We have conducted detailed direct water contact observations in a village in Northern Senegal during the first years of a massive Schistosoma mansoni outbreak to determine the role of human water contact in the extent of the epidemic. We quantified water contact activities in terms of frequency and duration, and described how these vary with age and sex. Moreover, we assessed the relationship between water contact- and infection intensity patterns to further elucidate the contribution of exposure to the transmission of schistosomiasis. RESULTS: This resulted in over 120,000 recorded water contacts for 1651 subjects over 175 observation days. Bathing was the main activity, followed by household activities. Frequency and duration of water contact depended on age and sex rather than season. Water contacts peaked in adolescents, women spent almost twice as much time in the water as men, and water contacts were more intense in the afternoon than in the morning, with sex-specific intensity peaks. The average number of water contacts per person per day in this population was 0.42; the average time spent in the water per person per day was 4.3 minutes. CONCLUSIONS: The observed patterns of water contact behavior are not unusual and have been described before in various other settings in sub-Saharan Africa. Moreover, water contact levels were not exceptionally high and thus cannot explain the extremely high S. mansoni infection intensities as observed in Northern Senegal. Comparison with fecal egg counts in the respective age and sex groups further revealed that water contact levels did not unambiguously correspond with infection levels, indicating that factors other than exposure also play a role in determining intensity of infection
Communities of practice: the missing link for knowledge management on implementation issues in low-income countries? [Viewpoint]
No full textThe implementation of policies remains a huge challenge in many low-income countries. Several factors play a role in this, but improper management of existing knowledge is no doubt a major issue. In this article, we argue that new platforms should be created that gather all stakeholders who hold pieces of relevant knowledge for successful policies. To build our case, we capitalize on our experience in our domain of practice, health care financing in sub-Saharan Africa. We recently adopted a community of practice strategy in the region. More in general, we consider these platforms as the way forward for knowledge management of implementation issues
Mouse models for pathogenic African trypanosomes: unravelling the immunology of host-parasite-vector interactions
No full textAfrican trypanosomiasis is a parasitic disease that affects a variety of mammals, including humans, on the sub-Saharan African continent. To understand the diverse parameters that govern the host-parasite-vector interactions, mouse models for the disease have proven to be a cornerstone. Despite the fact that most trypanosomes cannot be considered natural pathogens for rodents, experimental infections in mice have shed a tremendous amount of light on the general biology of these parasites and their interaction with and evasion of the mammalian immune system. Different aspects including inflammation, vaccine failure, antigenic variation, resistance/sensitivity to normal human serum and the influence of tsetse compounds on parasite transmission have all been addressed using mouse models. In more recent years, the introduction of various 'knock-out' mouse strains has allowed to analyse the implication of various cytokines, particularly TNF, IFNgamma and IL-10, in the regulation of parasitaemia and induction of pathological conditions during infection
Improved PCR-RFLP for the detection of diminazene resistance in Trypanosoma congolense under field conditions using filter papers for sample storage
No full textPerformance of a rapid and simple HIV testing algorithm in a multicenter phase III microbicide clinical trial
No full textA multi-test sequential algorithm based on Rapid/Simple (R/S) assays was applied for the diagnosis of HIV infection among participants in a phase 3 microbicide effectiveness trial. HIV testing was performed on finger-prick blood samples from patients after their enrollment in the trial. The specimens were tested in a serial procedure using three different rapid tests (Determine HIV-1/2 (Abbott), SD Bioline HIV 1/2 3.0 (Standard Diagnostics), and Uni-Gold HIV (Trinity Biotech)). In the event of discordant results between the Determine HIV 1/2 and SD Bioline HIV 1/2 3.0 tests, a third assay (i.e., Uni-Gold HIV) determined the final outcome. When the final outcome was positive, a second specimen was collected and tested with the same algorithm, only if a positive result was obtained with this sample the participant was informed of her positive serostatus. A total of 5734 post-enrollment specimens obtained from 1398 women were tested. Forty-six women tested positive according to the testing algorithm performed on the first collected specimen. Confirmatory testing results obtained at the ITM confirmed that 42 women were truly infected. Two out of four initial false positives tested negative upon testing of a second blood specimen. The other two tested false positive twice using specimens collected on the same day. A high percentage of specimens reactive with the Determine HIV-1/2 assay only were observed in the study site in Kampala. This result did not appear to be associated with pregnancy or malaria infection. HIV testing algorithms including only R/S assays are suitable for use in clinical trials, provided that adequate quality assurance procedures are in place