RULERS OF VIRULENCE In the Philippine infectious-disease landscape, no threat is too old and vanquished to be discounted nor too new and speculative to be disregarded
By Grace Roxas, Contributing Writer
"Some of the leading causes of morbidity and mortality in the Philippines today are similar to the leading causes of morbidity and mortality in the US before World War II which was the period prior to the wide-scale implementation of that country's immunization program," observes Dr. Celia Carlos, president of the Pediatric Infectious Disease Society of the Philippines (PIDSP). The other diseases stir up more recent memories of widespread alarm, with at least one posing a still largely spectral threat that may eclipse all the rest should the object of the fear materialize. Beyond the headlines are virulent diseases that routinely take their toll on the population in a less dramatic but more sweeping fashion, coming in as some of the leading causes of morbidity and mortality in the country in terms of sheer numbers affected.
Dysentery, malaria, measles, and tuberculosis continue to serve notice that they are not to be relegated to the dustbins of vanquished threats even with substantial gains in combating them in the past. Dr. Eric Tayag, director of the Department of Health's National Epidemiology Center (DOH NEC), says that recent outbreaks of dysentery and malaria, the anticipated failure in meeting the elimination goal for measles this year, and the emergence of multidrug-resistant (MDR) tuberculosis have put these old diseases back in the center of the government's threat radar. With the dysentery cases traced to shigella-a bacterium transmitted through the ingestion of contaminated food and water-and happening mostly in the provinces (Bohol, Bicol, Cotabato, Cavite), authorities suspect antiquated water systems as the root of the problem, a possibility that may open the floodgates to new outbreaks in other areas with old water infrastructure. Although 87 percent of households now have access to toilets, a related concern is the improper location of these toilets near the water sources, thus leading to contaminating run-offs during rains. The recent malaria outbreaks, on the other hand, take progress to task for introducing industrial development into semirural areas that are traditional nests for the vector mosquitoes. Tayag notes that at least two of the areas where recent cases are reported mostly involve patients who relocated there to work in the industrial sites-a new, problematic twist to a disease that is endemic in 65 out of the 78 Philippine provinces and is consistently one of the 10 leading causes of morbidity in the country. One year shy of the target year for its elimination, measles in 2007 showed the effects of accumulated poor coverage (less than 95 percent) for mass-immunization activities done starting 1998, with outbreaks documented in Metro Manila, Zamboanga, and Basilan. This led the DOH to do a massive follow-up vaccination in the last quarter of 2007, targeting nine million children up to 48 months of age. Tayag qualifies that although the ramping up of measles cases from one in 2006 to nearly 140 by the end of 2007 is a cause for alarm, outbreaks like these are expected to happen in the course of eliminating a disease. Carlos also points out that giving the measles vaccine in the past as part of the country's expanded program of immunization, inadequate though it may be, has gone a good way toward reducing measles cases as indicated by the almost nil hospital admissions for the disease during the expected peak season in the colder months of the year.
The outlook for tuberculosis in general is a brightening spot in the infectious-disease landscape as the country gets ready to exit the global list of countries with a high disease burden. "The incidence is still high (136/100,000) but the trend is going down," says Tayag. "We have one of the success stories for TB compared with other countries. Being removed from the list means that the money we invest in TB may now go to other programs." But the MDR issue, with its negative implications on first- and second-line treatment options, and the risk of TB coupling with HIV/AIDS-a combination with a fast lethal course-will still keep vigilance alive for TB, he adds. The invisible menace of a new strain of the pandemic influenza is again hovering after completing its 30- to 40-year cycle of mutation. The last global episode happened in Hong Kong in 1967, preceded by the 1958 Asian-flu and the 1918 Spanish-flu pandemics. According to Tayag, experts agree that the bird-flu pandemic is an indicator that the new strain will come from the bird-flu family, with the new strain expected to breach the current dead end in transmission from bird to human. "There will be so many deaths, mostly affecting children, and the surge capacity of even the most determined country will not be enough, so that it will require a global response," Tayag predicts. The unprecedented ease of international travel is a factor that might grossly affect the course of the disease.
Meanwhile, dengue's three-year cycle has become viciously shorter and it is now a year-round threat, instead of a seasonal concern before the onset of the rainy season. The 2007 incidence was the highest recorded yet, recording an 18- to 25-percent increase from the previous year. "It's getting worse every year and this is mainly because the four serotypes of the dengue virus are all circulating at the same time, and so practically everyone can get ill repeatedly," explains Tayag. "The only good news is that if DOH hasn't been doing a year-round campaign, baka mas malala pa ang dengue." Control measures have also stabilized the case-fatality rate (the proportion of death to the number of cases) to less than one percent despite the marked increase in the incidence, especially in the Visayas and Mindanao. Less dramatic but troubling more Filipinos in recent memory on any given day are the four top causes of morbidity in the country: acute lower-respiratory infections and pneumonia, diarrheal diseases, bronchitis/bronchiolitis, and the seasonal flu. Chickenpox also hits a substantial number, with infant vaccination not guaranteeing immunity among older children. Pneumonia and chronic lower-respiratory diseases, along with tuberculosis, also kill more than other infectious diseases in the country and represent 20 percent of the deaths among the 10 leading causes of mortality.
HIV/AIDS and food poisoning are on the high watch list of infection-related cases in 2007 not so much for the numbers of those affected (HIV/AIDS prevalence remains low) as in the context of issues related to their management. "We have to spend more, work more just to maintain that low level of prevalence (for HIV/AIDS)," says Tayag, "unlike for the other diseases where you spend on controlling outbreaks and reducing the number of cases." The Joint United Nations Program on HIV/AIDS (UNAIDS) has downgraded incidence estimates for the Philippines from 12,000 in 2005 to half of that last year. As of October last year, the actual cases are only half of the new estimate (2,977). Despite the low figures, the government sees possible weak links among injecting drug users who share needles and blood donors, citing the 20 individuals screened for blood donations last year and found to be HIV-positive instead. Tayag warns that contaminated blood was one of two factors that accelerated the HIV/AIDS crisis in Africa. For food poisoning, the government is looking at the longer chain of events that goes beyond isolated cases of food spoilage and deals with the economics of food production. As prices of food go up, a rise in food-poisoning cases is likely to take place as well, since food-related businesses cut corners to keep their products competitive and profitable. It can start at the farm where livestock fed antibiotics build up drug resistance in the humans who will ingest the substance from the flesh. Cost-cutting measures such as cooking in bulk and selling "double-dead" meat, as well as the propensity of economizing families to eat cheap fast food outside are the other high-risk activities for food poisoning. Says Tayag: "We believe that food poisoning is underreported because it's self-limiting and halos walang namamatay. It's a silent epidemic and a big burden. The few that get reported by the media are only the high-profile ones." He adds that the real burden might be so big that only about one percent actually gets reported.
The repertoire of anti-infectious-disease initiatives for 2008 will include new policies and interventions beyond the formal pale of health services, such as pushing for new infrastructure in water utilities and surveillance of farm-to-market practices among food manufacturers. Coinciding with the stepped-up effort to anticipate the new strain of the pandemic flu, revised international health regulations have been issued on the control of the spread of diseases and any other biologic, chemical, and geologic events with an impact on health stretching across national borders. DOH has issued an administrative order outlining the integrated disease surveillance and response on the local- and national-government levels. There is also an ongoing initiative with the Research Institute for Tropical Medicine for two years now to collect specimen from patients with influenza-like illnesses in several sentinel sites across the country. "The best guarantee we have right now that we will be able to respond immediately is being able to do early detection," explains Tayag. Against dysentery, the DOH will be mapping out areas where the old water systems need to be rehabilitated. The concerned local-government units will then be advised to make repairs before the rainy season. In coordination with the Housing and Urban Development Coordinating Council, the DOH hopes to resolve the tricky situation in high-risk slum areas by encouraging relocation of the informal settlers instead of encouraging them to stay on by fixing the water facilities where they are. These efforts are also seen to address vector control for dengue. Says Tayag: "Our vector control remains ineffective. It should be sustainable and community-based. The government can't do it alone because it requires searching and destroying every mosquito breeding site." The enormity of this task has led authorities to try to narrow down the suspect breeding sites that are driving the epidemic. With the much-awaited dengue vaccine expected to be available only by 2012, vector control and prompt supportive treatment would have to suffice for the moment. Tayag explains that those who discovered the vaccine are making sure that the protection is against the four serotypes and that it will not aggravate the illness. Unlike with other infectious diseases, a second dengue infection is not only possible but could be worse than the first one. The vaccine could also trigger a second infection if administered on a previously ill patient. For malaria, there is a new therapeutic outlook as the government introduces a new drug this year, the Artemisinin combination treatment, to replace the drug-resistance-inducing chloroquine. This is part of a concerted effort (DOH's disease-free-zones initiative) to control outbreaks as elimination is targeted for more and more endemic provinces. Other diseases covered by the disease-free-zones push are rabies, measles, and leprosy. For rabies and measles, as well as for pneumonia, chickenpox, and other infectious diseases with existing vaccines, immunization will be the most critical response. The government is introducing a second dose for measles, and hepatitis-B vaccination will be made available to all newborns.
Meanwhile, the PIDSP, together with the Philippine Pediatric Society and the Philippine Foundation for Vaccination, has finished updating its recommended childhood-immunization schedule. These recommendations, updated yearly, can guide the government and organizations involved in child health in making improvements in existing immunization programs. The PIDSP recommends the inclusion the pneumococcal conjugate vaccine (PCV) for pneumonia, as well as vaccines for Haemophilus influenzae type B, rotavirus for certain viral diarrheas, influenza, hepatitis A, human papilloma virus (HPV), and rabies. Booster shots are recommended for varicella; measles, mumps, and rubella; diphtheria, pertussis, and tetanus; and polio. Giving due consideration to these recommendations, the DOH, Tayag says, will ensure that resources will be available for the provision of the Hib vaccine. However, the government remains unconvinced that there are enough cases to justify a mass vaccination program for PCV. |
