Lymphatic Filariasis known as “Elephantiasis”, is a chronic parasitic infection that puts at risk more than a billion people in 83 countries including the Philippines.
      The disease is caused by thread-like parasitic filarial worms, which lodge in the nodes andvessels of the lymphatic system. These worms live for about 10 years producing millions of immature microfilariae that circulate in the blood.
      Filariasis is transmitted when a mosquito bites an infected person, which sucks the microfilariae. These microfilariae develop into the infective stage inside the mosquito for about three weeks and may be transferred into an uninfected individual. This larva lodge into the lymph vessels and lymph glands, which develop into adult male and female worms. The male and female worms copulate and produce millions of microfilaria. This microfilaria circulates into the bloodstream and may be sucked by a mosquito vector and the cycle may be repeated.  After 5-15 years without intake of anti-filarial drugs, the adult male and female worms eventually die in the lymph nodes. After the death of the adult parasites, granulation tissue around the dead parasite results in obstruction of lymphatic channels. This produces extensive debilitation and disfigurement resulting to social stigma. The  debilitation and consequent productivity loss together with the social and psychological problems which Filariasis patients experience inflict a great burden on affected families, communities and the country as a whole.
Filariasis and its control in the Zamboanga Peninsula
Filariasis remains one of the public health problems in the Philippines. In Zamboanga Peninsula, Zamboanga Del Norte is the only Province which registers Filaria cases especially in hard to reach areas. Although not a killer disease, its economic and psychosocial effects in individuals and communities in endemic areas cannot be ignored. Lymphatic Filariasis is considered a low priority problem compared to other acute diseases like dengue, H-fever, measles, etc. That is why this disease is under the umbrella of neglected tropical diseases (NTD). The reasons are primarily due to chronicity and non-killing nature of the disease. Moreover, reports of disease occurrence do not run to large numbers possibly because the disease is either undiagnosed or misdiagnosed.
Two filarial species exist in the Philippines, namely, Wuchereria bancrofti and Brugia malayi. Mosquito vectors responsible for transmitting the parasite are the following; Aedes poecilius- primary vector, Anopheles flavirostris-secondary vector, Mansonia bonnea,Mansonia uniformis & Culex quinquefasciatus.
It is irregular in distribution and is limited to areas wherein the environment favors propagation of specific insect vectors of the parasite. It was discovered 90 years ago by foreign workers. A preliminary survey done in 1959 in 18 Provinces revealed an 8.8 % prevalence rate.  Region 9 was not included in the survey because of organizational limitations and logistic and manpower insufficiency although there are already reported cases of hydrocoele.  Because of this, a National Filariasis Control Program (NFCP) was created in 1963 after a national survey conducted in 1960 showed 43 provinces endemic for the disease. It is being implemented in the field through the three Filariasis Control Units (FCUs) based on Regions 5,8 & 11. Originally created to handle prevention and control in the three major island groups (Luzon,Visayas,Mindanao), re-organization in the Department of Health (1987) limited the activities of the FCUs to the respective regions where they are based.
The re-organization in 1987 had placed the control program under the communicable disease control service, sharing a budget with other communicable disease programs. In 1996, a separate budget was allotted to the program.
In 1997, in line with the WHO overtures for elimination of Filariasis as a public health problem, and, with the new tools in diagnosis and treatment which makes elimination feasible, the National Filariasis Control Program (NFCP) started shifting its strategies to elimination (NFEP).
            In 1998 a prevalence research study was conducted in Zamboanga Peninsula in order to document the existence and prevalence of Lymphatic Filariasis. The study was piloted   in the municipality of Baliguian, Zamboanga Del Norte based on records review of hydrocoele cases in the Municipality. Baliguian then was the first documented Municipality in the Region with Lymphatic Filariasis cases. Results revealed that there are 146 Filaria cases in the Municipality with microfilaria rate of 5 and a prevalence rate of 23.4/1000 population. Because of this data, the municipality was directed to conduct the Mass Treatment Administration of Diethylcarbamazine 50mg/tablet and albendazole 400mg/tablet yearly.
            In 2001, a survey was conducted through nocturnal blood examination in Labuan District, Zamboanga City. The result showed 16 cases out of 156 persons examined. This revealed 10.3 microfilaria rate.
In 2002, another community diagnostic survey was conducted in 7 municipalities of Zamboanga Del Norte and 4 municipalities in Zamboanga Sibugay the Region.
The result of the survey showed that in Zamboanga Del Norte out of the1, 247 persons examined, 143 were positive for Filariasis.  Municipalities that were positive include Manuel Roxas, Sibuco, Siocon, Katipunan, Jose Dalman, Manukan and Sindangan.  In Zamboanga Sibugay, there were 5 municipalities discovered with Filariasis. These include R.T Lim Municipality, Titay, Buug, Malangas and Naga.
In 2007, the community diagnostic of Lymphatic Filariasis prevalence survey have identified 25 endemic municipalities and two cities out of 35 municipalities surveyed in the Peninsula. Most of the endemic areas belong to the 4th – 6th class municipalities, majority are hard to reach areas which affected inhabitants belong to lowest socio economic groups.
Because of the increasing number of filaria cases in the Philippines including Zamboanga Peninsula, President Gloria Macapagal Arroyo signed Executive order no. 369 dtd 2004. This executive order reiterates the intake of Filariasis mass drug Diethylcarbamazine and albendazole of all 2 years old and above in all endemic provinces.
            With the advent of this strategy supported by an executive order, after more than 10 years, all provinces showed decreasing trend of Filariasis cases. In fact, Zamboanga Sibugay and Zamboanga Del Sur achieved 0 filaria case by the year 2015. This was brought about by good mass drug administration coverage (>85%). Because of these good achievements, in 2015 transmission assessment survey I was conducted in these two provinces.  Result showed 0 antigen rate in Zamboanga Sibugay and Zamboanga Del Sur hence mass drug administration implementation had been stopped. For Zamboanga Del Norte, out of 3, 208 examined only 25 were found positive for Filariasis. This is 75% decreased compared to our baseline data in 1998 survey. This clearly shows that mass drug administration implementation strategy is effective in reducing filaria case in endemic municipalities.
            In 2015, two Provinces in Zamboanga Peninsula (Zamboanga Del Sur and Zamboanga Sibugay) were qualified as Candidate for Filariasis Free Province.  Because of this status, Mass Drug Administration Implementation in these two Provinces was stopped. In 2016 only Zamboanga Del Norte Province, Isabela City and Zamboanga City implemented the two Drugs Combination of Lymphatic Filariasis Mass Drug Administration Implementation. This coming July 2017, still the Province of Zamboanga Del Norte, Zamboanga City and Isabela City will continue to conduct the Mass Drug Administration implementation.
Healthy and productive individuals and families for a Filaria-free Philippines by 2020
Elimination of filariasis as a public health problem through comprehensive approach & universal access to quality health services.
1. Sustain >85% Mass drug administration coverage in all endemic provinces
2 .<.01 microfilaria rate in all endemic provinces.