'Disease detectives’ lead hunt for invisible killer COVID-19 in PH

Christian V. Esguerra, ABS-CBN News

Posted at Apr 01 2020 09:30 PM

MANILA — A team in hazmat suits descended on a densely packed neighborhood in Valenzuela City in response to a call that a resident was showing severe flu-like symptoms. 

The group, collectively known as the City Epidemiology and Surveillance Unit, navigated the narrow entry to the compound, then carefully took a swab from the person’s throat and nose, a crucial step in determining if he had contracted COVID-19.

While awaiting official test results that could take days, the team went on to identify those who had close contact with the person, now classified as a “person under investigation.”

Should anyone of them develop similar symptoms, however mild, they were told to inform the surveillance team immediately, a protocol that applied strictly to other communities being watched for possible outbreak. 

It’s a tedious and indispensable process that’s done over and over again to make sure that the fast-spreading disease, which has killed at least 37,000 people and threatened to paralyze economies worldwide, will be contained.

In the Philippines, the total death count is 96 from 2,311 confirmed infections as of Wednesday.


The hunt begins with epidemiology teams working round the clock as the new coronavirus continues to wreak havoc across continents.

“They’re the ones who hunt down what we call the invisible ones, people who we don’t know if they are positive or negative for COVID,” Dr. Jaime Exconde Jr., Valezuela’s chief health officer, told ABS-CBN News.

They are called “disease detectives,” who play a key role in a gripping medical “whodunit,” said Dr. Enrique Tayag, who headed the country’s National Epidemiology Center for 10 years.

Epidemiology is described as a “science of high importance,” a method to identify the “distribution of diseases, factors underlying their source and cause, and methods for their control.”

In short, it looks at the big picture and goes to the root causes of say, disease outbreaks, to determine what should be done to contain them. Epidemiologists are the eyes and ears on the ground, gathering all relevant data and making sense of them.

“It’s the heart of public health,” Tayag told ANC’s Matters of Fact podcast.


The Philippines, with a population of 105 million, has around 120 certified epidemiologists, meeting the global standard of one such expert for every 1 million people, Tayag said.

In Valenzuela, the city government beefed up its 15-man epidemiology and surveillance units with trained nurses spread to different barangay (village) health offices, said Exconde.

Last February, the interior department instructed local governments to put up one “Barangay Health Emergency Response Team” for every 5,000 people within their respective areas.

Policy decisions, such as the current 30-day lockdown of the entire Luzon island, are driven by data collected and analyzed through epidemiology, said Tayag.

The work doesn't stop with keeping as many people as possible under home quarantine, and practicing a strict 1-meter physical distancing.

Surveillance teams closely monitor areas for confirmed and possible cases, details of which would indicate if the enhanced community quarantine is actually working.

The “next 1 or 2 weeks will be really crucial” in answering this question, said Dr. Edsel Maurice Salvaña, an infectious diseases specialist, noting that many of the recent confirmed cases were likely infected before the lockdown was imposed.

A person infected with the new coronavirus usually falls sick within 5 to 14 days.

It’s only by the third or fourth week of the lockdown, said Salvaña, that health officials will know if the spread of the virus is slowing down and flattening the infection curve.


“To slow down transmission, you need to know the enemy,” said Tayag, who is also one of the country’s only around 250 infectious diseases specialists.

Knowing the enemy also requires actual testing.

The Department of Health has been under pressure to conduct “mass testing,” which, Tayag said, could be the direction now that more testing kits are coming in.

Described as a “game changer” is the SARS Cov2 kit of Gene Xpert recently approved by the Food and Drug Administration. It will make use of existing machines available all over the Philippines and currently used for tuberculosis tests.

But Tayag clarified that mass testing does not mean “testing everyone” for COVID-19.


“Kasi ganito yan. Pag may mass testing, ano ugali ng Pilipino? Kung sino yung hindi dapat i-test, sila pa yung nauuna. Alam mo naman yung nangyari. Wala pa nga yung mass testing, nagpapa-test yung hindi dapat i-test,” he said.

(It's like this. If there's mass testing, how do Filipinos behave? Those who do not need to be tested are the ones who take it first. You know what happened here. Even though there is still no mass testing, those who do not need to be tested are taking the tests.) 

Tayag said mass testing should be “carefully planned” and give priority to those showing symptoms, especially serious cases.

Medical frontliners should also be tested regularly even if they don’t manifest any symptom, he said, noting that it’s important for doctors and nurses attending to COVID-19 patients to have “peace of mind.” 

Well-planned testing will allow government to make better use of limited resources, particularly during contact-tracing, which, he said, need not be done in cases where someone is tested only because of cough but later turns out to be negative for the new coronavirus.

Tayag said authorities, in this case, could then zero in on people who came in close contact with positive cases, with tests available to those who would later fall ill.