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Introduction
With the massive epidemic that hit Luzon in 1995 caused by FMD serotype O Cathay topotype, the President of the Republic of the Philippines declared the whole of Luzon a calamity area (June 1995) through an executive order appropriating funds for control and eradication of FMD. This paved the way for a vigorous and sustained effort to control and eradicate the disease. The Department of Agriculture (DA) through the Bureau of Animal Industry (BAI) created the National FMD Task Force (NFMDTF) in 1995 to focus on the control of the disease. A National FMD Control and Eradication Plan was developed and anchored on four components: surveillance, public awareness campaign, animal movement management, and vaccination.
Livestock Production
Philippine agriculture plays a vital role in the economy. This attaches high priority in transforming agriculture into a modern, dynamic and competitive sector. A sustained expansion of the national economy requires sustained growth in the agricultural sector. To date, agriculture accounts for a significant part of the country’s gross domestic product (GDP) with the livestock subsector accounting for 13.28% of total agricultural production.
Livestock production in the Philippines in general has continued to be the domain of smallholders and an important contributor to the economy. At the farm level, livestock-raising is a major activity in rural areas. For a large proportion of smallholder households engaged in livestock raising, the activity is the primary source of income. The Philippine swine industry, along with poultry, has consistently dominated other livestock industries in terms of volume and value of production. The gross value of livestock output is P154.7 billion at current prices. As of January 2008, the country has a total susceptible livestock inventory of 23.8 million, of which 3.3 million are carabao, 2.6 million are cattle, 4.2 million are goats and 13.7 million are pigs. More than 80% of susceptible livestock in the country are with the small hold farmers. Of the 13.7 million pigs, 78% are with the small holders while 22% are with the commercial raisers. The presence of a disease as important as FMD has a very clear impact on the industry as experienced by the government and industry stakeholders during the 1995 FMD epidemic in the country.
FMD History
FMD was first documented in Manila in 1902 from cattle imported in Hong Kong. It was not until 1908 however, that the first epidemic occurred when a shipment of infected cattle from Hong Kong arrived in Manila, spreading the disease to 25 provinces. From then on until prior to World War II, the disease was recorded almost every year, but only in ruminants. The first reported case of FMD in swine was in 1954 during the restocking period that followed World War II. Outbreaks repeatedly occurred in 1954, but were subsequently reduced to sporadic cases from 1955 to 1959.
No FMD outbreak was reported from 1960 to 1964, but was again reported in the Province of Nueva Ecija in 1965. This led to a series of outbreaks continuing to 1966 and spreading to most provinces in Luzon. Incidence of the disease then tapered off from 1967 to 1970 and was absent on 1971. In 1975 however, a number of outbreaks occurred and the disease was reported in Visayas and Mindanao.
In the 1980’s, FMD was endemic in Luzon. Outside Luzon, the disease was last seen in General Santos City in Mindanao in 1988. In the early 1990’s, FMD remained sporadic in some areas in Luzon and it was in 1995 that a new epizootic spread to 27 provinces in Luzon tallying the highest recorded number of outbreaks in a single year at 1,553. Fig.6 shows the number of FMD outbreaks from 1995 to 2008.
In 1996, the number of outbreaks was drastically reduced to 392. The number of provinces affected also declined gradually from that period and no serotype other than Type O was detected in Luzon. FMDV Type O affected 22 provinces in 1996 and slightly increased to 24 in 1997.
Gradually, the areas affected decreased until 2004 wherein a dramatic decrease had been recorded from 14 provinces to only 7 in 2005.
The last outbreak in the Visayas was recorded in Iloilo in September 1999. With the outbreaks then confined only to Luzon Island, the country applied to OIE for Mindanao and Visayas, Palawan and Masbate, respectively, to be recognized as FMD free without vaccination. Zone Mindanao was recognized as FMD free without vaccination in 2001 while Zone Visayas, Palawan, and Masbate in 2002.
From 2002 to 2003, the majority of the outbreaks occurred in backyard farms in Zone 2 while from 2004 to 2005 outbreaks were mostly recorded in slaughterhouses.
FMD Virus Serotypes
Prior to 1995, there were 3 FMD virus serotypes in the Philippines – serotype O1 Campos, A24 Cruzeiro and C3 Philippines closely related to C3 Resende. Serotype O1 Campos caused a major epidemic in 1972 and continued sporadic outbreaks until 1988 when it was last confirmed in Isabela province. The A24 Cruzeiro serotype was first confirmed in the country in 1975 affecting mainly Luzon, causing major outbreaks during that year but became sporadic later with its last outbreak detected in 1983 in Central Luzon. Serotype C was first confirmed in 1976 and also caused major outbreaks until early 1980’s. The outbreaks then became sporadic and the last outbreak was diagnosed in Bulacan in 1995.
Trivalent vaccines (O1, A24 and C3) from manufacturers from Europe and Latin America were mainly used to control FMD outbreaks in the 1970’s and the 1980’s. In the 1990’s, vaccines were purchased only from Europe. Coupled with vaccination, animal movement control, particularly shipments from one island to another had been strictly regulated leading to confinement of FMD outbreaks on Luzon Island.
The FMD virus serotype O Cathay topotype was first detected in August 1994 in a backyard piggery in Rizal province. It later caused a major outbreak spreading to 27 provinces in Luzon in 1995.
Evidence shows that serotype O Cathay topotype was the only remaining FMD virus circulating in Luzon after 1995. From 1999 to 2005, all of the epithelial samples from suspected and confirmed outbreaks that were tested in the National FMD Diagnostic Laboratory were confirmed as serotype O. Samples were also sent to the World Reference Laboratory in Pirbright for confirmation. The last outbreak of serotype O Cathay topotype was detected in Quezon province in December 28, 2005.
