Global Programme to Eliminate Lymphatic Filariasis
In 1997, following advances in diagnosis and treatment of the disease, WHO classified lymphatic filariasis, along with five other infectious diseases, as eradicable or potentially eradicable. The same year, the World Health Assembly adopted Resolution WHA 50.29, which called on Member States to initiate steps to eliminate lymphatic filariasis as a public health problem. In response to this call, WHO launched the Global Programme to Eliminate Lymphatic Filariasis in 2000.
The elimination strategy has two components: (1) to stop the spread of infection (interrupting transmission); and (2) to alleviate the suffering of affected populations (controlling morbidity).
In order to interrupt transmission, districts in which lymphatic filariasis is endemic must be mapped and community-wide mass treatment programmes implemented to treat the entire at-risk population. Most of these programmes are based on once-yearly administration of single doses of two drugs given together. The following recommended drug regimens need to be administered once a year for at least 5 years, with a coverage of at least 65% of the total at-risk population:
1. Stop the spread of infection - MDA
In order to interrupt transmission, districts in which lymphatic filariasis is endemic must be mapped and a strategy of preventive chemotherapy called mass drug administration (MDA) implemented to treat the entire at-risk population. The following drug regimens are recommended for use in annual MDA for at least 5 years with a coverage of at least 65% of the total at-risk population:
- 6 mg/kg of body weight diethylcarbamazine citrate (DEC) + 400 mg albendazole; or
- 150 µg/kg of body weight ivermectin + 400 mg albendazole (in areas that are also endemic for onchocerciasis).
- 400 mg albendazole preferably twice per year (in areas that are also endemic for Loa loa).
An alternative and equally effective community-wide regimen in endemic regions is the use of common table salt or cooking salt fortified with DEC for a period of one year.
In addition to preventative chemotherapy, surveillance is conducted in order to monitor and evaluate the coverage and transmission status of lymphatic filariasis within districts that receive mass drug administration (MDA). If all eligibility criteria are met after 5 consecutive years of MDA, Transmission Assessment Survey (TAS) is conducted in order to determine if transmission has been interrupted and MDA can stop. TAS also serves as post-MDA surveillance to detect whether recrudescence of transmission has occurred.
2. Alleviate suffering - MMDP
Successful MDA will prevent new infections and therefore result in no new cases of clinical disease. To achieve the second aim of GPELF, a core strategy of morbidity management and disability prevention (MMDP) is needed. Suffering caused by the disease can be alleviated through a minimum recommended package of care to manage lymphedema and hydrocele. These services should be available within primary health care systems in all areas of known patients.