• The World Health Organisation (WHO) announced that Brazil eliminated lymphatic filariasis as a public health problem.

• Globally, Brazil joins 19 other countries and territories that have been validated by WHO for having eliminated lymphatic filariasis as a public health problem. 

• The other countries are: Malawi and Togo in the African Region; Egypt and Yemen in the Eastern Mediterranean Region; Bangladesh, Maldives, Sri Lanka and Thailand in the South-East Asia Region; and Cambodia, Cook Islands, Kiribati, Lao People’s Democratic Republic, Marshall Islands, Niue, Palau, Tonga, Vanuatu, Vietnam and Wallis and Futuna in the Western Pacific Region.

• Lymphatic filariasis, commonly known as elephantiasis, is a debilitating parasitic disease spread by mosquitoes. For centuries, this disease has afflicted millions worldwide, causing pain, chronic, severe swelling, serious disability, and social stigmatisation.

• In the Americas, three endemic countries (Dominican Republic, Guyana, and Haiti) still require mass drug administration to stop transmission and are working to achieve the elimination target.

• In addition to being the 20th country to be validated for elimination of lymphatic filariasis as a public health problem, Brazil has also become the 53rd country to have eliminated at least one neglected tropical disease, globally.

• Over the past few decades, Brazil has implemented integrated actions to eliminate lymphatic filariasis, including the development of a national plan to fight this disease in 1997, the mass distribution of antiparasitic drugs, vector control activities, and strong surveillance, particularly in the most affected areas. With these efforts, the country achieved the end of disease transmission in 2017.

Key facts about Lymphatic filariasis:

• Lymphatic filariasis, commonly known as elephantiasis, is a neglected tropical disease. Infection occurs when filarial parasites are transmitted to humans through mosquitoes. Infection is usually acquired in childhood and causes hidden damage to the lymphatic system.

• The painful and profoundly disfiguring visible manifestations of the disease – lymphoedema, elephantiasis and scrotal swelling – occur later in life and can lead to permanent disability. 

• Over 657 million people in 39 countries worldwide remain threatened by lymphatic filariasis and require preventive chemotherapy to stop the spread of this parasitic infection.

• People affected by lymphatic filariasis are not only physically disabled, but suffer mental, social and financial losses contributing to stigma and poverty.

Cause and transmission

Lymphatic filariasis is caused by infection with parasites classified as nematodes (roundworms) of the family Filariodidea.

There are 3 types of these thread-like filarial worms:

i) Wuchereria bancrofti, which is responsible for 90 per cent of the cases.

ii) Brugia malayi, which causes most of the remainder of the cases.

iii) Brugia timori, which also causes the disease.

• Mosquitoes are infected with microfilariae by ingesting blood when biting an infected host. 

• Lymphatic filariasis is transmitted by different types of mosquitoes, for example by the Culex mosquito, widespread across urban and semi-urban areas, Anopheles, mainly found in rural areas, and Aedes, mainly in endemic islands in the Pacific.

Symptoms

• The majority of infections are asymptomatic, showing no external signs of infection while contributing to the transmission of the parasite. 

• These asymptomatic infections still cause damage to the lymphatic system and the kidneys and alter the body’s immune system.

• When lymphatic filariasis develops into chronic conditions it leads to lymphoedema (tissue swelling) or elephantiasis (skin/tissue thickening) of limbs and hydrocele (scrotal swelling). 

Treatment

• Elimination of lymphatic filariasis is possible by stopping the spread of the infection through preventive chemotherapy. 

• The WHO recommended preventive chemotherapy strategy for lymphatic filariasis elimination is mass drug administration (MDA). 

• MDA involves administering an annual dose of medicines to the entire at-risk population. 

• The medicines used have a limited effect on adult parasites but effectively reduce the density of microfilariae in the bloodstream and prevent the spread of parasites to mosquitoes.

India on mission mode to eliminate lymphatic filariasis by 2027

• India’s efforts to eliminate lymphatic filariasis have made substantial strides with the introduction of the Enhanced Strategy for LF Elimination by 2027. 

• Currently, lymphatic filariasis has been reported in 345 districts across 20 states and Union Territories, with 90 per cent of cases burden contributed by eight states — Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra, Odisha, Uttar Pradesh, and West Bengal. 

• India has implemented a comprehensive five-pronged strategy to combat lymphatic filariasis, which includes mission mode Mass Drug Administration (MDA), Morbidity Management and Disability Prevention (MMDP), Vector Control (Surveillance and Management), High-Level Advocacy, and Innovative Approaches.

• This strategy incorporates a mission-mode annual MDA campaign, held biannually on February 10 and August 10, alongside National Deworming Day (NDD).

Manorama Yearbook app is now available on Google Play Store and iOS App Store