Parasites

Filariasis in the Philippines

Author Dr. Stephen Berger , 07-10-2008

Table of contents
Lifecycle of Wuchereria bancrofti, an agent of Filariasis

The lifecycle of Wuchereria bancrofti, one of the causal agents of Filariasis (Source: CDC)

 

645,232 cases of filariasis (both forms) were estimated for the Philippines from 1963 to 1996.

Wuchereria bancrofti

Time and Place:

– Bancroftian filariasis is endemic to southern Luzon, Mindanao, Mindoro, Palawan, Samar, Leyte, Sorsogon and Bohol.
– 43 of 63 provinces were endemic n 1960; 45 of 77 provinces as of 1996 4; 290 municipalities as of 2001; 351 of 1,566 municipalities as of 2003; 39 of 79 provinces as of 2004.
– Cases have recently been registered in Marinduque.
– Both forms of filariasis (W. bancrofti and B. malayi) coexist in only four provinces: Davao Oriental, Palawan, Eastern and Northern Samar 6, and Surigao del Sur.
– In 1984, 20 million persons were considered at risk for filariasis (both W. bancrofti and B. malayi) in the Philippines; 23.5 million in 2002; 15,034,765 in 2006; 21,882,581 in 2007.
– Only two provinces (Marinduque and Sulu) were considered ‘high prevalence’ areas (>10%) as of 1993.

Disease in the Philippines is nocturnally periodic.

Prevalence surveys:

37% of males and 17% of females in a village on Catanduanes (microfilaremia, 1978 publication)
13% in Bayanan and 3.4% in Manganan (Mindoro, microfilaremia, 2004 publication)

Vectors:

– The local vectors are Anopheles minimus flavirostris, Aedes poicilius , Culex quinquefasciatus, and Ochlerotatus (Finlaya) niveus.

Brugia malayi

Time and Place:

– Brugia malayi infection is endemic to southwestern Palawan, Sulu, Agusan, and Samar.
– Both forms of filariasis (W. bancrofti and B. malayi) coexist in only four provinces: Davao Oriental, Palawan, Eastern Samar, and Surigao del Sur.
– Brugia malayi was first confirmed in the Philippines in 1964 – in Palawan (33.1% local prevalence at the time).
– 43 of 63 provinces were endemic for filariasis in 1960; 45 of 77 provinces as of 1996. 1
– In 1984, 20 million persons were considered at risk for filariasis (both W. bancrofti and B. malayi) in the Philippines.

Vectors:

– The local vectors are Mansonia uniformis, Mansonia bonnea, and Mansonia dives.
– Mansonia dives is associated with both nocturnally periodic and subperiodic microfilaremia patterns on Palawan.

Mass treatment with diethylcarbamazine and albendazole was administered to 1,945,121 persons in 2001.
– 9,881,124 persons received mass treatment in 2005 ; 10,174,936 in 2006; 13,627,661 in 2007

Author
Dr. Stephen Berger

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