Lymphatic filariasis is one of the neglected tropical diseases. It is estimated that 120 million people are currently infected and that 1.403 billion live in areas where filariasis is endemic. Lymphatic filariasis is a leading cause of chronic disability worldwide, including of 15 million people who have lymphoedema (elephantiasis) and 25 million men who have hydrocoele.

Lymphatic filariasis is one of the neglected tropical diseases. It is estimated that 120 million people are currently infected in 73 countries where filariasis is endemic. Lymphatic filariasis is a leading cause of chronic disability worldwide, including of 15 million people who have lymphoedema (elephantiasis) and 25 million men who have hydrocoele.

 Integrated Vector Management (IVM) is defined as "a rational decision-making process for the optimal use of resources for vector control". The approach seeks to improve the efficacy, cost-effectiveness, ecological soundness and sustainability of disease-vector control. The ultimate goal of IVM is to prevent the transmission of vector-borne diseases such as malaria, dengue, lymphatic filariasis, leishmaniasis, schistosomiasis and Chagas disease.
 WHO promotes the principles of IVM as set out in the “Global strategic framework for integrated vector management”. It lists five key elements of IVM: capacity building; advocacy and social mobilization; legislation framework; evidence-based decision-making; and integrated approaches. This framework is in line with the global plan for 2008-2015 to combat neglected tropical diseases through delivery of multi-intervention packages, which also promotes the IVM approach.
 In 2008, WHO produced the position statement on IVM to support the advancement of IVM as an important component of vector-borne disease control. The member states are invited to accelerate the development of national policies and strategies, while international organizations, donor agencies and other stakeholders are encouraged to support the capacity strengthening necessary for implementation of IVM.
 In order to take the next step and to transform the framework and policies into actual implementation, the first IVM stakeholders meeting was held in Geneva in November 2009. The meeting developed a roadmap aimed at strengthening evidence-based decision-making for new initiatives and recommended the establishment of a partnership mechanism to facilitate effective information sharing and foster better collaboration with regards to the implementation of IVM.
 This paper introduces the IVM position statement in Japanese language with the aim of disseminating the concept and approach of IVM in Japan.

Since its establishment in 1948, the World Health Organization (WHO) has organized a series of expert committee meetings to address individual tropical diseases that are included in WHO’s list of neglected tropical diseases (NTDs) in order to formulate appropriate evidence-based control strategies. Between 1948 and 2012, as many as 66 resolutions have been adopted for individual diseases. In response to trends in the global public-health agenda—notably primary health care in the 1970s and the Millennium Development Goals in the 2020s—WHO established the Department of Control of Neglected Tropical Diseases in 2005. The aim was to contribute to poverty alleviation and achievement of the Millennium Development Goals by addressing 17 NTDs in an integrated manner rather than by vertical disease-specific programmes.
Since then, WHO has led a dynamic trend in the global community to overcome NTDs, including organization of the first global partners meeting on NTDs in 2007, publication of the first WHO report on NTDs in 2010 and in 2012 the WHO roadmap to accelerate work towards the 2015 and 2020 targets for control, elimination and eradication of NTDs, and the announcement in 2013 of the London Declaration by 13 pharmaceutical companies and various donors and partners, and the publication of the second WHO report on NTDs. In May 2013, the World Health Assembly adopted the first resolution to call for increased efforts and support to control, eliminate and eradicate NTDs as a whole, contrary to the past disease-specific resolutions.
The present paper is intended to introduce Japanese audiences in the field of public health to this 66th World Health Assembly Resolution on NTDs and to the work of WHO in leading the global trend towards control and elimination of NTDs.

Background
Samoa was formerly highly endemic for Wuchereria bancrofti filariasis transmitted by Aedes mosquitoes. Previous control efforts including sporadic mass drug administration (MDA) campaigns have reduced the prevalence to low levels but have not succeeded in eliminating the disease. To effectively plan, model and evaluate the worldwide elimination effort, the Global Programme to Eliminate Lymphatic Filariasis (GPFLF) needs data on filariasis epidemiology (including age and sex-specific prevalence and the density of microfilariae (Mf)) and estimates of the number of years of MDA required for elimination. The five-year nationwide MDA campaign carried out in Samoa before the start of the Pacific Programme to Eliminate Lymphatic Filariasis (PacELF) generated extensive data on these issues.
Methodology⁄Principal Findings
MDA campaigns were conducted in Samoa with diethylcarbamazine (DEC) in 1993 to 1995 and DEC plus ivermectin in 1996 to 1997 for all persons aged 2 years and above. Coverage of the MDA, as assessed from the campaign village register books, ranged from 62% to 97% depending on the year, and was over 80% in three out of five years. Village based surveys showed that prevalence of Mf declined from 4.3% in 1993 (N=10,256) to 1.1% in 1998 (N=4,054) (Pχ²=94.4, p<0.001). Males had a three- to five-fold higher prevalence than females, and this difference remained consistent over the five-year period. Transmission was still occurring over the period as shown by the occurrence of new infections in 3 children less than 5 years old out of 5,691 tested (five-year cumulative incidence of 0.53 per thousand children for the period 1993 to 1998). There was a statistically significant reduction in the geometric mean number of Mf per 60 μl in positive cases between 1993 (11.8) and 1998 (6.9) (t=2.61; p<0.01). The proportion of people with a high density of Mf - over 60 Mf per 60 μl (1000 per ml) - declined from to 19.4% to 4.0% (Pχ²=5.6, p=0.018).
Conclusions⁄Significance
Five years of sustained MDA with DEC (3 years) and DEC plus ivermectin (2 years) reduced the prevalence of Mf of W.bancrofti in Samoa by 74%. Density of Mf in infected individuals was also significantly reduced. Males had a three to five-fold higher prevalence than women. New infections in children less than five years old still occurred at a low level, suggesting that transmission was not completely interrupted. These findings helped to prepare a sound monitoring and evaluation plan for PacELF.