Peru's Human Plague Outbreak: Rats, Sugarcane, and the Challenges of Regional Education and Response
September 25, 2010
Michèle Ledgerwood
Senior Research Fellow, Global Health Policy Center, CSIS
During a visit to Peru in late August to research the scientific contributions and regional partnerships of the U.S. Naval Medical Research Center Detachment in Lima and its permanent field office in Iquitos, our CSIS team had recurrent conversations about the recent outbreak of human plague in the district of Chocope, department of La Libertad, roughly 600 kilometers (375 miles) north of Lima.
Peru is no stranger to infectious diseases, acute febrile illnesses, and recurrent viral infections, many of which are zoonotic or vector-borne in origin. Yellow fever, dengue fever, and various strains of influenza are annual visitors, and 2010 has seen outbreaks of both Oropouche fever and human rabies as well (the latter transmitted by vampire bats). The diversity of Peru's geographic landscapes – from desert to mountain highlands to lush jungle – results in a rare variety of both disease and immunological response. In the coming years, the completion of the Interoceanic Highway has the potential to broaden the complexity of the epidemiological environment even further.
During this summer's outbreak, 31 cases of human plague were reported in the space of two months, resulting in three deaths. The majority of those cases were bubonic, with four pneumonic and one septicemic. Although isolated cases of human plague are reported in Peru almost every year, this was the country's first epidemic of bubonic plague since 1994, when 35 people died and more than 1,100 infections were diagnosed.
The recent outbreak was of particular concern to Peruvian public health officials and researchers because it occurred in a province that is home to two of Peru's most important export harbors and is traversed by the Pan-American Highway. Bubonic plague generally is carried by rodents and transmitted to humans either by fleas, who act as vectors for the disease, or via human handling of infected animals (alive or dead). In Chocope, rats reside in the sugarcane crops. When the crops are burned prior to harvest, the rats flee to the surrounding farming huts, triggering the onset of human infection.
One official we interviewed suggested that the Peruvian Ministry of Health's (MOH) initial concern stemmed from reports of an apparent lack of mortality in the infected rats, and a fear that they might migrate en masse to nearby urban areas. This possibility is still being researched. If true, it could have interesting implications for future outbreaks, particularly as global warming trends portend an increase in the number of host rodents in the years to come.
As neighboring Bolivia contends with its own outbreak of bubonic plague, Peru continues its surveillance of the disease, and the MOH is working on a broader public education campaign. Although Peru's economy continues to grow and the country is beginning to roll out a 
long-anticipated framework law for Universal Health Insurance (Aseguramiento Universal en Salud), significant inequalities remain. The extreme poverty and abysmal hygienic conditions in many Peruvian villages create the potential for more rapid and extensive transmission of disease during an outbreak. Improving the dissemination of health information in both rural and remote areas therefore is critical.
The implementation of Peru's national health policies is the responsibility of each individual Regional Health Authority (Dirección Regional de Salud, or DIRESA) in Peru's 25 regions. Not surprisingly, there are significant geographic disparities in both the quality of healthcare services and the management of outbreaks. As a result, the Pan American Health Organization (PAHO) is advocating for better education of both regional health providers and regional governments. One of the recent victims of fatal pneumonic plague transmission was a medical student at the Universidad Nacional de Trujillo, who intubated an infected patient without taking adequate prophylactic measures. A recent statement by fellow medical students in support of their deceased colleague directly targets the incident management approaches of the La Libertad DIRESA, and highlights the challenges of implementing appropriate epidemiological practices across disparate regions – an issue that PAHO sees as critical.
For an excellent Spanish-language article on public health concerns related to the plague outbreak in Peru, please see PAHO's website here. For more general information on the plague, please see the U.S. Centers for Disease Control and Prevention's Plague Home Page.
What are your thoughts about Peru’s plague outbreak? What public health education strategies would be most effective in this context? Leave your comments below.
