Advances and challenges in predicting the impact of lymphatic filariasis elimination programmes by mathematical modelling

Mathematical simulation models for transmission and control of lymphatic filariasis are useful tools for studying the prospects of lymphatic filariasis elimination. Two simulation models are currently being used. The first, EPIFIL, is a population-based, deterministic model that simulates average trends in infection intensity over time. The second, LYMFASIM, is an individual-based, stochastic model that simulates acquisition and loss of infection for each individual in the simulated population, taking account of individual characteristics. For settings like Pondicherry (India), where Wuchereria bancrofti infection is transmitted by Culex quinquefasciatus, the models give similar predictions of the coverage and number of treatment rounds required to bring microfilaraemia prevalence below a level of 0.5%. Nevertheless, published estimates of the duration of mass treatment required for elimination differed, due to the use of different indicators for elimination (EPIFIL: microfilaraemia prevalence < 0.5% after the last treatment; LYMFASIM: reduction of microfilaraemia prevalence to zero, within 40 years after the start of mass treatment). The two main challenges for future modelling work are: 1) quantification and validation of the models for other regions, for investigation of elimination prospects in situations with other vector-parasite combinations and endemicity levels than in Pondicherry; 2) application of the models to address a range of programmatic issues related to the monitoring and evaluation of ongoing control programmes. The models' usefulness could be enhanced by several extensions; inclusion of different diagnostic tests and natural history of disease in the models is of particular relevance

The Long Term Effect of Current and New Interventions on the New Case Detection of Leprosy: A Modeling Study

Leprosy is a contagious disease that will remain prevalent, despite the declining number of patients worldwide over the last century. With approximately 250,000 new cases detected annually, leprosy is far from being eradicated. Leprosy can be treated with drugs after disease detection

Південноукраїнські історики та російська академічна еліта: етапи та напрямки співпраці у другій половині ХІХ – на початку XX ст.

У статті на широкій джерельній базі досліджено інфраструктурні та особисті зв’язки між південноукраїнськими істориками та академіками Санкт-Петербурзької (Російської) Академії наук впродовж другої половини ХІХ ст. – 1920-х років.The article, based on a great number of sources, researches the infrastructural and personal contacts between the historians of South Ukraine and academicians of the St.-Petersburg Academy of Sciences throughout the second half of the ХІХ century – 1920-ies

Health Seeking Behaviour and Utilization of Health Facilities for Schistosomiasis-Related Symptoms in Ghana

The World Health Organization recommends that long-term benefit of schistosomiasis control should include treatment in local health facilities. This means that patients should visit a hospital or clinic with their complaints. However, little is known about whether they do so. We conducted a study in three regions of Ghana and interviewed two thousand people about whether they recently had schistosomiasis-related symptoms such as blood in urine or blood in faeces, and what they had done about it. We included fever (mostly caused by malaria) for comparison. We found that 40% of patients with urinary symptoms sought care compared to 70% of those with intestinal symptoms and 90% with fever. Overall, only 20% of all schistosomiasis-related symptoms were reported to a hospital or clinic, compared to 30% for fever. Self-medication with allopathic (i.e., orthodox) medicines was the main alternative. Our study showed that the most important determinant for seeking health care or visiting a health facility is perceived severity of the symptom. Factors such as age, sex, socio-economic status and geographic region showed no impact or a clear pattern. We conclude that many schistosomiasis patients do not visit a health facility, the only place with effective drugs, necessitating additional control measures

Irreversible Effects of Ivermectin on Adult Parasites in Onchocerciasis Patients in the Onchocerciasis Control Programme in West Africa

Ivermectin is an effective drug for the treatment of human onchocerciasis, a disease caused by the parasitic filarial nematode Onchocerca volvulus. When humans are treated, the microfilariae normally found in the skin are rapidly and very nearly completely eliminated. Nonetheless, after a delay, microfilariae gradually reappear in the skin. This study is concerned with the causes of this delay. Hypotheses are tested by comparing the results of model calculations with skin microfilaria counts collected from 114 patients during a trial of five annual treatments in the focus area of Asubende, Ghana. The results obtained strongly suggest that annual treatment with ivermectin causes an irreversible decline in microfilariae production of ∼30%/treatment. This result has important implications for public health strategies designed to eliminate onchocerciasis as a significant health hazar

Impact of ivermectin on onchocerciasis transmission: assessing the empirical evidence that repeated ivermectin mass treatments may lead to elimination/eradication in West-Africa

BACKGROUND: The Onchocerciasis Control Program (OCP) in West Africa has been closed down at the end of 2002. All subsequent control will be transferred to the participating countries and will almost entirely be based on periodic mass treatment with ivermectin. This makes the question whether elimination of infection or eradication of onchocerciasis can be achieved using this strategy of critical importance. This study was undertaken to explore this issue. METHODS: An empirical approach was adopted in which a comprehensive analysis was undertaken of available data on the impact of more than a decade of ivermectin treatment on onchocerciasis infection and transmission. Relevant entomological and epidemiological data from 14 river basins in the OCP and one basin in Cameroon were reviewed. Areas were distinguished by frequency of treatment (6-monthly or annually), endemicity level and additional control measures such as vector control. Assessment of results were in terms of epidemiological and entomological parameters, and as a measure of inputs, therapeutic and geographical coverage rates were used. RESULTS: In all of the river basins studied, ivermectin treatment sharply reduced prevalence and intensity of infection. Significant transmission, however, is still ongoing in some basins after 10–12 years of ivermectin treatment. In other basins, transmission may have been interrupted, but this needs to be confirmed by in-depth evaluations. In one mesoendemic basin, where 20 rounds of four-monthly treatment reduced prevalence of infection to levels as low as 2–3%, there was significant recrudescence of infection within a few years after interruption of treatment. CONCLUSIONS: Ivermectin treatment has been very successful in eliminating onchocerciasis as a public health problem. However, the results presented in this paper make it almost certain that repeated ivermectin mass treatment will not lead to the elimination of transmission of onchocerciasis from West Africa. Data on 6-monthly treatments are not sufficient to draw definitive conclusions

High Incidence of Pulmonary Tuberculosis a Decade after Immigration, Netherlands

Incidence rates of pulmonary tuberculosis among immigrants from high incidence countries remain high for at least a decade after immigration into the Netherlands. Possible explanations are reactivation of old infections and infection transmitted after immigration. Control policies should be determined on the basis of the as-yet unknown main causes of the persistent high incidence

Anaplasma phagocytophilum from Rodents and Sheep, China

Three strains were isolated and characterized

Macrofilaricides and onchocerciasis control, mathematical modelling of the prospects for elimination

BACKGROUND: In most endemic parts of the world, onchocerciasis (river blindness) control relies, or will soon rely, exclusively on mass treatment with the microfilaricide ivermectin. Worldwide eradication of the parasite by means of this drug is unlikely. Macrofilaricidal drugs are currently being developed for human use. METHODS: We used ONCHOSIM, a microsimulation mathematical model of the dynamics of onchocerciasis transmission, to explore the potentials of a hypothetical macrofilaricidal drug for the elimination of onchocerciasis under different epidemiological conditions, as characterized by previous intervention strategies, vectorial capacity and levels of coverage. RESULTS: With a high vector biting rate and poor coverage, a very effective macrofilaricide would appear to have a substantially higher potential for achieving elimination of the parasite than does ivermectin. CONCLUSIONS: Macrofilaricides have a substantially higher potential for achieving onchocerciasis elimination than ivermectin, but high coverage levels are still key. When these drugs become available, onchocerciasis elimination strategies should be reconsidered. In view of the impact of control efforts preceding the introduction of macrofilaricides on the success of elimination, it is important to sustain current control efforts

Effect of Micronutrient and Probiotic Fortified Yogurt on Immune-Function of Anti-Retroviral Therapy Naive HIV Patients

Background: Micronutrient supplementation has been shown to reduce the progression of HIV but does not have an effect on the intestinal barrier or the intestinal microbiota of HIV patients. Studies have suggested that probiotics could potentially complement micronutrients in preserving the immune-function of HIV patients. Objective: Assess the impact of micronutrient supplemented probiotic yogurt on the immune function of HIV patients. Design:We performed a randomized, double blind, controlled trial with CD4 count as primary outcome among HIV patients naïve to anti-retroviral treatment. Secondary outcomes included hematological parameters, incidence of diarrhea and clinical symptoms. A total of 112 HIV patients were randomized to receive a micronutrient fortified yogurt with (n = 55) or without additional probiotic Lactobacillus rhamnosus GR-1 (n = 57) for four weeks. Results:An average decline in CD4 count of −70 cells/μL (95% CI: −154 to −15) was observed in the micronutrient, probiotic group versus a decrease of −63 cells/μL (95% CI: −157 to −30) in the micronutrient control group (p = 0.9). Additional probiotic supplementation was well tolerated and not associated with adverse events. No difference between groups was detected in incidence of diarrhea or clinical symptoms. An improvement of hemoglobin levels was observed for all subjects, based upon a mean difference from baseline of 1.4 g/L (SD = 6) (p = 0.02). Conclusion:The addition of probiotics to a micronutrient fortified yogurt was well tolerated by HIV patients but was not associated with a further increase in CD4 count after one month