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Chikungunya in the Philippines

The following background is abstracted from Gideon and the Gideon e-book series. [1,2]

Most cases of Chikungunya in the Philippines are reported in the center and south of the country.
– Epidemics were reported in 1954, 1956, 1968 and 1985 to 1986.
– In 1986, an outbreak (3 cases) of Chikungunya was reported among U.S. Peace Corps volunteers stationed in the Philippines (Mindanao, Cebu and Mashbate).
– In 2009, several Filipino tourists acquired Chikungunya in Thailand.
– Cynomolgus monkeys (Macaca fascicularis) are implicated as reservoirs in this country.

Seropositivity toward a related agent, Getah virus, has been reported among humans on Palawan, without signs of overt infection.
– Getah virus has also been identified in Nueva Ecija Province.

1. Berger SA. Infectious Diseases of the Philippines, 2012. 389 pages, 74 graphs, 1588 references. Gideon e-books,
2. Berger SA. Chikungunya and Zika: Global Status, 2012. 43 pages, 12 graphs, 1154 references. Gideon e-books,

Note featured on ProMED

Schistosomiasis in the Philippines

The following background data on schistosomiasis in the Philippines are abstracted from the Gideon e-book series. [1,2] (Primary references available on request).

Time and Place:
Schistosomiasis was first reported in the Philippines in 1906.
During the 1970’s schistosomiasis was endemic to:
– Mindoro Oriental and Sorsogon in Southern Luzon
– The provinces of North, East and Western Samar
– Leyte
– Bohol in Eastern Visayas
– All the provinces of Mindanao with the exception of Misamis Oriental, Davao Oriental and Maguindanao.
The disease is currently most common in Bohol, Lake Naujan, coastal Mindanao, Samar and southeastern Luzon.

In 1921, an estimated 25,000 to 30,000 people were infested – this number had increased to 300,000 by 1948.
– Ten million live in endemic areas, as of 2002, an estimated 800,000 were infested and 6.7 million were at risk.
– As of 2010, an estimated 560,000 persons were infested.
– 12,273 cases of schistosomiasis were officially reported in 1988; 4,240 in 2000; 6,628 in 2004; 9,383 in 2005; 3,517 in 2006
– 301 deaths were ascribed to schistosomiasis in 1988.

– Infection is common among dogs.
– Infection is common among field water buffaloes and rats on Leyte.
– The local snail reservoir is Oncomelania hupensis quadrasi

Prevalence surveys:
36.0% in rice farming villages on Leyte (2005 publication)
20% in Mindanao, Leyte, Samar and Mindoro (1941)
16% in Malay-balay, Mindanao (1981 publication)
20% in Oriental Mindoro (1978)
15% in North Samar (1977 publication)
49.5% in Bolos and Gamapin barangays (rural Luzon, 1978)
80% of children in eastern Leyte (1945)
17.4% of humans, 0.5% of cats, 7% of dogs, 0.1% of pigs, 37.6% of rats and 0.1% of water buffalo in Western Samar (2003 to 2004)
1.6% to 86.3% of dogs, 0.1% to 21.7% of cats, 0.01% to 18.4% of pigs, 0.1% to 72.5% of water buffaloes, and 0.7% to 95.4% of rats in Samar Province (2007 publication)
0% to 45.2% of rural villagers in Samar Province (2003 to 2004)
5% in Trinidad and Talibon townships, Bohol Province (1980 publication)
10% in Surigao del Norte (2005)
10% to 15% of pigs and water buffalo in endemic areas.
1.6% to 86.3% of dogs in 50 endemic villages, 0.1% of 21.7%, 0.01% to 18.4% of pigs, <0.1% to 72.5% of water buffaloes, and 0.7% to 95.4% of rats. (Samar Province, 2007 publication) 51.5% of buffaloes in Macanip, Leyte (PCR, 2008) Notable outbreaks: 1944 to 1945 - An outbreak (1,700 cases) was reported among United States and Australian Army personnel (174 cases) serving in the Philippines. 2000 - An "outbreak" was reported in Davao del Sur, with 222 cases as of October - most in the barangays of Digos- Igpit, Colorado, and Matti. References: 1. Berger SA. Infectious Diseases of the Philippines, 2011. 379 pages, 72 graphs, 1264 references. Gideon e-books.
2. Berger SA. Schistosoma Japonicum: Global Status, 2011. 14 pages, Gideon e-books.

Update: Posted in ProMED

Rabies in the Philippines

Although the incidence of rabies has declined somewhat in recent years, disease rates per 100,000 continue to be higher in the Philippines than those of neighboring countries. [1,2] See graph

1. Berger SA. Infectious Diseases of the Philippines, 2010, 1,131 pp. Gideon e-book series.
2. Berger SA. Rabies: Global Status, 2010, 353 pp. Gideon e-book series.

Leptospirosis in the Philippines

A recent outbreak in Manila belies the fact that reported rates of leptospirosis in the Philippines had actually decreased in recent years. See graph:


The following additional background data are abstracted from GIDEON (primary references available on request):

Leptospirosis was first reported n the Philippines in 1932.
– 65 cases were documented in literature published during 1932 to 1970; 390 during 1971 to 1973; approxomately 840 during 1998 to 2001.
– Leptospirosis is common in flood-prone areas of urban setting such as Metro Manila.
– The average age of patients is 32 years, 87% of cases were males and 70% are outdoor workers.
– The case fatality rate is 12 to 14 percent.
– Rates in Cabatuan, Iloilo are estimated at 147 cases per 100,000 population (2007 publication).

Prevalence surveys:
5% of aseptic meningitis cases in Manila (1989 publication)

Seroprevalence surveys:
43.6% of rice farmers in Central Luzon (1988 publication)
0% of dogs (RMAT, 1970 to 1973)

The following serovars of Leptospira interrogans have been demonstrated among patients in the Manila area: poi, tarassovi, manilai, pyrogenes, australis, grippotyphosa, javanica and automnalis.

Notable outbreaks:
1976 to 1983 – An outbreak of leptospirosis was reported on a penal farm in Sablayan, Mindoro.
1999 – An outbreak (17 cases) of leptospirosis involved participants in an ‘iron-man contest’ – from Germany, Hong Kong and the Philippines.

Update: Posted in ProMED

Measles in the Philippines

A recent outbreak in Western Visayas belies the fact that measles rates in the Philippines have declined dramatically since the 1990’s, in parallel with increased vaccination usage.


From 1983 to 1997, the Philippines had reported one of the highest measles rates in this region.


Filariasis in the Philippines

645,232 cases of filariasis (both forms) were estimated for the Philippines during 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.