Lymphatic Filariasis Control in Tanzania: Effect of Repeated Mass Drug Administration with Ivermectin and Albendazole on Infection and Transmission

Lymphatic filariasis (LF) is a disabling mosquito borne parasitic disease and one of the major neglected tropical diseases. In most countries of Sub-Saharan Africa the control of LF is based on yearly mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. We monitored the effect of 3 repeated MDAs with this drug combination, as implemented by the Tanzanian National Lymphatic Filariasis Elimination Programme, on human infection and mosquito transmission during a five-year period (one pre-intervention and four post-intervention years) in a highly endemic community in north-eastern Tanzania. After start of intervention, human infection with the blood-stage larva of the parasite (microfilaria) initially decreased rapidly, leading to considerable reduction in transmission. The effects thereafter levelled off and transmission still occurred at low level after the third MDA. The MDAs had limited effect on molecular markers of adult worm burden (circulating filarial antigens) and transmission exposure (antibodies to Bm14 antigen) in the human population. The study highlights the importance of monitoring and regular evaluation in order to make evidence based programme adjustments, and it points to a need for further assessment of the long-term effect of repeated ivermectin/albendazole MDAs (including the importance of application intervals and treatment coverage), in order to optimize efforts to control LF in sub-Saharan Africa

Lymphangiogenesis and Lymphatic Remodeling Induced by Filarial Parasites: Implications for Pathogenesis

Even in the absence of an adaptive immune system in murine models, lymphatic dilatation and dysfunction occur in filarial infections, although severe irreversible lymphedema and elephantiasis appears to require an intact adaptive immune response in human infections. To address how filarial parasites and their antigens influence the lymphatics directly, human lymphatic endothelial cells were exposed to filarial antigens, live parasites, or infected patient serum. Live filarial parasites or filarial antigens induced both significant LEC proliferation and differentiation into tube-like structures in vitro. Moreover, serum from patently infected (microfilaria positive) patients and those with longstanding chronic lymphatic obstruction induced significantly increased LEC proliferation compared to sera from uninfected individuals. Differentiation of LEC into tube-like networks was found to be associated with significantly increased levels of matrix metalloproteases and inhibition of their TIMP inhibitors (Tissue inhibitors of matrix metalloproteases). Comparison of global gene expression induced by live parasites in LEC to parasite-unexposed LEC demonstrated that filarial parasites altered the expression of those genes involved in cellular organization and development as well as those associated with junction adherence pathways that in turn decreased trans-endothelial transport as assessed by FITC-Dextran. The data suggest that filarial parasites directly induce lymphangiogenesis and lymphatic differentiation and provide insight into the mechanisms underlying the pathology seen in lymphatic filariasis

Is England closing the international gap in cancer survival?

Background: We provide an up-to-date international comparison of cancer survival, assessing whether England is 'closing the gap' compared with other high-income countries. Methods: Net survival was estimated using national, population-based, cancer registrations for 1.9 million patients diagnosed with a cancer of the stomach, colon, rectum, lung, breast (women) or ovary in England during 1995-2012. Trends during 1995-2009 were compared with estimates for Australia, Canada, Denmark, Norway and Sweden. Clinicians were interviewed to help interpret trends. Results: Survival from all cancers remained lower in England than in Australia, Canada, Norway and Sweden by 2005-2009. For some cancers, survival improved more in England than in other countries between 1995-1999 and 2005-2009; for example, 1-year survival from stomach, rectal, lung, breast and ovarian cancers improved more than in Australia and Canada. There has been acceleration in lung cancer survival improvement in England recently, with average annual improvement in 1-year survival rising to 2% during 2010-2012. Survival improved more in Denmark than in England for rectal and lung cancers between 1995-1999 and 2005-2009. Conclusions: Survival has increased in England since the mid-1990s in the context of strategic reform in cancer control, however, survival remains lower than in comparable developed countries and continued investment is needed to close the international survival gap