Lessons Learned from Dengue Surveillance and Research, Puerto Rico, 1899–2013

Dengue was first reported in Puerto Rico in 1899 and sporadically thereafter.Following outbreaks in 1963 and 1969, the Centers for Disease Control and Prevention has worked closely with the Puerto Rico Department of Health to monitor and reduce the public health burden of dengue.During that time, evolving epidemiologic scenarios have provided opportunities to establish, improve, and expand disease surveillance and interventional research projects.These initiatives have enriched the tools available to the global public health community to understand and combat dengue, including diagnostic tests, methods for disease and vector surveillance, and vector control techniques.Our review serves as a guide to organizations seeking to establish dengue surveillance and research programs by highlighting accomplishments, challenges, and lessons learned during more than a century of dengue surveillance and research conducted in Puerto Rico.I n 1916, Walter W. King (Figure 1), a surgeon in the US Public Health Service stationed at the San Juan (Puerto Rico) Quarantine Station, presented to the American Society of Tropical Medicine a firsthand account of his experiences during the 1915 dengue outbreak in Puerto Rico (1).Health Commissioner William Lippitt had invited Henry Rose Carter and William Gorgas to work with King, then a captain in the US Army Medical Corps, to determine whether yellow fever virus or dengue virus caused the outbreak.After Carter, who had survived a bout with yellow fever years earlier and thus was immune, fell ill soon after examining patients in a mosquito-infested hospital, the team concluded that dengue caused the outbreak (2).King credited Arthur H. Glennan, his predecessor at the San Juan Quarantine Station, as the first to have reported local dengue cases in Puerto Rico in 1899 (3).King also cited local physicians who reported having seen dengue cases nearly every year since and an apparent outbreak in 1905 (1).King noted that younger persons and residents of San Juan were affected more often than elderly persons and persons from rural areas and that the epidemic was associated with a "superabundance" of Aedes mosquitoes.In addition, dengue cases frequently appeared in the same household ≈2 weeks after the first household member fell ill, which suggested to King that infections might occur around the household.These observations collectively led King to suspect that dengue already was endemic in Puerto Rico by 1915.Many of King's prescient observations remain true.Yet, despite extensive resources expended to understand and combat dengue, rates of illness and death caused by dengue continue to increase worldwide (4).We describe lessons learned during >100 years of dengue surveillance and research in Puerto Rico.(Because the names of some entities have changed since 1899, we have used their contemporary names to maintain consistency.) Early Epidemiologic InvestigationsOnly 1 report of dengue in Puerto Rico was published in the nearly 50 years after King's report (5).In 1963, the Puerto Rico Department of Health (PRDH) requested assistance from the Centers for Disease Control and Prevention (CDC) to respond to a dengue outbreak in which ≈27,000 suspected cases were ultimately reported to PRDH by telegram from across the island (Table 1) (6,15).A team was sent from CDC headquarters to help PRDH respond to the outbreak, along with colleagues from CDC's Puerto Rico Field Station, which had been established in 1951 to research and control schistosomiasis and investigate rabies, histoplasmosis, and leptospirosis.Later known as the San Juan Laboratories, the Field Station had grown out of the Office of Malaria Control in War Areas, which became CDC in 1946.Through observation of 2,777 persons during the 1963 outbreak, dengue was described as an acute febrile illness lasting 4-7 days with infrequent minor hemorrhagic manifestations (6).Two thirds of persons with serologic evidence of infection reported a recent illness consistent with dengue (6).Distinct from King's observations from 1915, Lessons Learned from Dengue Surveillance and Research, Puerto Rico, 1899-2013