Parasites

Filariasis in the Philippines

Author Stephen A. Berger, MD , 07-Oct-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
Stephen A. Berger, MD

Stephen A. Berger, M.D. is affiliated with the Tel Aviv Medical Center, where he has served as Director of both Geographic Medicine and Clinical Microbiology. He also holds an appointment as Emeritus Associate Professor of Medicine at the University of Tel-Aviv School of Medicine. Dr. Berger co-founded GIDEON Informatics, developers of the GIDEON (Global Infectious Diseases and Epidemiology Online Network) web app, and the GIDEON series of ebooks.

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