Six formerly endemic countries recognized for eliminating the disease as public health problem
Data recently published by the World Health Organization (WHO) show that more than 556 million people worldwide were treated for lymphatic filariasis in 2015, compared with 538 million in 2014.
“Through national elimination programmes we targeted nearly 698 million people for treatment last year” said Dr Gautam Biswas, Coordinator of the Preventive Chemotherapy and Transmission Control unit of WHO’s Department of Control of Neglected Tropical Diseases. “As of early September 2015, just above 556 million were treated, which represents coverage of more than 79% of the targeted population. Although this is a great achievement, we know much more is needed to reach WHO’s 2020 Roadmap targets”.
Elimination of lymphatic filariasis is possible by stopping the spread of the infection.
WHO recommends annual treatment of all eligible populations in endemic areas with a single dose of two medicines: albendazole (400 mg) together with either ivermectin (150–200 µg/kg) or diethylcarbamazine citrate1 (6 mg/kg). Their effect reduces the density of microfilariae in the blood and prevents the spread of parasites to mosquitoes.
Large-scale treatment, or “preventive chemotherapy”, conducted annually for at least 5 years can interrupt transmission. Implementation of this strategy has reduced numbers of infections in the community; in 18 countries levels are so low that preventive chemotherapy can be stopped. By implementing surveillance and providing care to affected patients, six of these countries2 have demonstrated the elimination of the disease as a public health problem3.
By conducting transmission assessment surveys, national programmes can now determine whether to stop large-scale treatments. The survey results in 2015 revised down the population at risk of lymphatic filariasis in many areas where interventions occurred several times: the global number of people requiring treatment reduced from 1.4 billion in 2011 to 946 million in 2015.
Preventive chemotherapy is still required in 54 countries but has not been delivered to all endemic areas as of the end of 2015. Enhanced strategies are called for in about 29 countries to achieve the elimination targets and stop treatment by 2020.
““Achieving elimination as a public health problem is not an end in itself” said Dr Jonathan King, scientist and focal point for lymphatic filariasis elimination at WHO’s Department of Control of Neglected Tropical Diseases. “Continued surveillance is crucial as is the integration of morbidity management and disability prevention activities into public health systems as part of continued care to alleviate the suffering of people affected by this disease”.
Surgery can alleviate hydrocele (scrotal swelling) associated with the infection. Clinical severity and progression of the disease, including acute inflammatory episodes, can be reduced and prevented with simple hygiene measures, skin care, exercise and elevation of affected limbs. People with lymphoedema must have access to continuing care throughout their lives, both to manage the disease and to prevent its progression to more advanced stages.
Since 2000, a cumulative total of 6.2 billion treatments has been delivered to affected populations. The establishment that year of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has resulted in the prevention or cure of more than 97 million cases of lymphatic filariasis. This achievement is projected in turn to avert more than US$ 100 billion in economic losses of those who have benefitted from these treatments worldwide.
To achieve the WHO Roadmap targets for 2020, access to a minimum package of care must be assured for every person with associated chronic manifestations of lymphatic filariasis in all areas where the disease is present. The aim is to alleviate suffering and promote improvement in the quality of life of those affected.
Lymphatic filariasis is a parasitic disease that can result in an altered lymphatic system. Manifestation of the disease after infection takes time and can cause the abnormal enlargement of body parts leading to severe disability and social stigmatization. The parasites are transmitted by four main types of mosquitoes: Aedes, Anopheles, Culex and Mansonia.
-----------------------------------------------1DEC fortified salt for household use has been used as a public health tool in China and other countries against bancroftian and brugian filariasis as it can reduce infection levels below elimination thresholds. It is also one of the WHO-recommended strategies against lymphatic filariasis.
2Cambodia, Cook Islands, Maldives, Niue, Sri Lanka and Vanuatu.
3A process of validation is used to formally confirm elimination as a public health problem. Countries wishing to be recognized for their success can make a request to WHO for such acknowledgement along with submission of a dossier.