The Winter of Dengue Fever
“I’m on pesquizaje,” my daughter Rebecca told me. “All of the third, fourth and fifth year medical students at Allende have our classes suspended. We are going door-to-door looking for symptoms of dengue fever and checking for standing water.” 
As a fourth year medical student at Cuba’s ELAM (Escuela Latinoamericana de Medicina, Latin American School of Medicine in Havana), she is assigned to Salvadore Allende Hospital in Havana. It handles most of the city’s dengue cases. Though she has done health canvassing before, this is the first time she has had classes cancelled to do it. It is very unusual for an outbreak of dengue, a mosquito-borne illness, to occur this late in the season. She remembers most outbreaks happening in the Fall, being over before December, and certainly not going into January–February.
Groups of medical students are assigned to a block with about 135 homes, most having 2–7 residents. They try to check on every home daily, but don’t see many working families until the weekend. The first dengue sign they look for is fever. The medical students also check for joint pain, muscle pain, abdominal pain, headache behind the eye sockets, purple splotches and bleeding from the gums. What is unique about Cuban medical school is the way ELAM students are trained to make in-home evaluations that include potentially damaging life styles — such as having uncovered standing water where mosquitoes can breed.
Dengue is more common in Cuban cities of Havana, Santiago and Guantánamo than in rural areas. Irregular supply of water to the cities means that residents store it in cisterns. Cisterns with broken or absent lids and puddles from leaky ones are prime breeding sites for the Aedes aegypti mosquito, the primary vector (carrier) of dengue. 
DF and DHF
There is a significant difference between dengue fever (DF) and dengue hemorrhagic fever (DHF). DF is a virus which usually lasts a week or more and is uncomfortable but not deadly.  DF has four varieties (serotypes). If someone who has had one type of dengue contracts a different serotype of the disease, the person is at risk for DHF. Early DHF symptoms are similar to DF but the person can become irritable, restless and sweaty, and go into a shock-like state and die. 
DF can be so mild that many people never know that they had it and that they are at risk for the far more serious DHF. This is why the Cuban public health model of reaching out to people is important in preventing a deadly epidemic. There are no known vaccines or cures for DF or DHF — the only treatment is treating the symptoms. With DHF, this includes dealing with dehydration and often blood transfusions in intensive care. [3, 4]
Each year, there are over 100 million cases of DF, largely in sub-Saharan Africa, the Caribbean, Latin America, Southwest Asia, and parts of Indonesia and Australia.  Between 250,000 and 500,000 cases of DHF occur annually and 24,000 result in death. 
Dengue was not identified in Cuba until 1943. Epidemics hit the island in 1977–1978 (553,132 cases), 1981 (334,203 cases of DF with 10,312 cases of DHF), 1997 (17,114 DF cases with 205 DHF cases), and 2001–2002 in Havana (almost 12,000 DF cases). 
Climate, mosquitoes and health
Climate change could make conditions more comfortable for mosquitoes that are vectors for dengue. During the last half a century, Cuban health officials have calculated a 30 fold increase of Aedes aegypti mosquito.  Since the 1950s, the average temperature in Cuba has increased between 0.4 and 0.6°C. Health officials are well aware that “…increasing variability may have a greater impact on health than gradual changes in mean temperature…” 
The 1990s were a very hard time for Cuba. Known as the “special period,” this was when collapse of the Soviet Union caused oil to dry up, the nation’s production (including food) to plummet, and illnesses to increase.  It was also a time when there was a climb “in extreme weather events, such as droughts, and…stronger hurricane seasons.”  Increases in climate variability meant winters have become warmer and rainier.
Conner Gorry, Senior Editor of MEDICC Review in Havana, reports that “My friends and neighbors tell me they can’t remember ever having to fumigate or think about dengue in the winter.”  Another consequence of a more ups and downs in the climate is “…insults to the upper respiratory tract, increasing viral transmission, particularly among infants and children.” 
Medical students in Havana come from 100 countries about the globe.  No matter what accent they have when speaking Spanish, they don’t have trouble getting into homes. In Havana, there is nothing unusual about a foreigner in a bata (white medical jacket) walking through homes, poking into yards and peering on roofs to see if there is standing water.
Always in need of extra cash, an enormous number of Cubans have some sort of less than totally legal activity going on in their homes (such as a nail parlor in the living room). But it does not occur to either the resident or the medical student that the inspection would be for anything other than public health reasons.
Cuba has experienced more than half a century of mobilization campaigns like current efforts to control dengue. Soon after the 1959 revolution Cuba mobilized the literacy campaign which sent teachers and students to every corner of the island to teach citizens to read and write. Every hurricane season, the neighborhood Committees for Defense of the Revolution (CDRs) are prepared to move the elderly, sick and mentally ill to higher ground if an evacuation is necessary. Campaigns against diseases like polio and dengue have made Cubans used to the government bringing public health efforts into their homes. 
Beginning in the 1960’s, the CDRs worked with thousands of trainers, who, in turn trained 50,000 more Cubans to teach the importance of polio vaccinations. As a result, Cuba has not had a polio death since 1974. CDRs actively encourage pregnant women to regularly visit their neighborhood doctor’s office and patrol the community to enforce the ban on growing succulents that attract mosquitoes. 
Cuba places a very high value on researching preventive medicine. MEDICC Review (Medical Education Cooperation with Cuba) is a peer reviewed open access journal which works to enhance cooperation among “global health communities aimed at better health outcomes.” 
Cuban researchers have played a key role in developing the widely accepted model that DHF is determined by “the interaction between the host, the virus and the vector in an epidemiological and ecosystem setting”  In Cuba, this translates to (a) the most important risk factor for getting DHF is having a second infection of DF which is a different strain; (b) being infected a second time in a specific order of DF strains places children at a higher risk for DHF than adults; (c) white Cubans are at a higher risk for DHF than Afro-Cubans; but, (d) those who already have sickle cell anemia, bronchial asthma or diabetes are at higher risk.
Cuban researchers openly discuss weaknesses in their health care system. One study indicated that there could be a “marked undercounting” of dengue due to missing a large number of cases. This finding occurred even though the study examined data during a time of “maximum alert,” suggesting that undercounting could be very widespread. 
A typical finding is that the community must feel that the dengue control program belongs to them if it is to be successful and sustainable.  Some of the best work I’ve seen on the role of public health takes an honest look at effects of “the absence of active involvement of the community” in dengue control. The authors felt that Cuba’s outdoor spraying of adult mosquitoes “is of questionable efficacy.” Instead, they focused on “the bad conditions or absence of covers on water storage containers” in the city of Guantánamo. 
The study had a control group of 16 neighborhoods which carried out the usual practices of home inspections, measuring the degree of mosquito infestation, and larviciding (applying chemicals to kill mosquitoes during the larval stage of growth). In contrast, their intervention group did everything that the control group did, but added intense involvement by local activists. “Formal and informal leaders” of the community worked with health professionals “to mobilize the population and change behavior,” such as covering water containers correctly, repairing broken water pipelines, and not removing larvicide.
Measuring the number of mosquitoes in the two groups revealed dramatic results. The authors concluded that “Community based environmental management integrated in a routine dengue prevention and control program can reduce level of Aedes infestation by 50–75%.” 
Rebecca told me that when medical students inspect the homes of Havana residents, they find that the overwhelming majority comply with pubic health policy. But some do not. A few cannot afford the proper lid for cisterns. Some have mental problems that limit their ability to cooperate. And a very few just don’t give a damn, even if they could be raising mosquitoes that infect their neighbors. Cuban-style public health research is critical in identifying barriers that communities need to overcome if they are to protect themselves from disease.
Do you remember Katrina and the number of New Orleans residents who languished while the state and national governments did nothing meaningful? Do you remember the photos of 1000 Cuban doctors in batas ready and waiting to come to New Orleans just like they went to Nicaragua, Honduras, Haiti, Venezuela, Sri Lanka, Pakistan and dozens of other countries hit by disasters? Do you remember the government that would increase the suffering of its own people rather than accept help from Cuba?
It may be difficult, but imagine that, at the height of the Katrina disaster, the US closed medical schools in Gulf coast states and coordinated the work of attending to medical and public health needs of the poorest in New Orleans. It may contradict your lifetime of experiences, but imagine that medical schools across the US sent their students to survey living conditions of poor black, brown, red, yellow and white Americans to determine what causes elevated mortality rates and then announced that no one would return to medical school until they were part of a national plan to resolve health care needs.
It may bend your mind to the border of hallucination, but imagine that health care professionals throughout the world demanded that people of the Global South be spared the mosquito infestations, rising waters, droughts, floods, species extinctions and all other manifestations of climate change brought on by the gluttonous overproduction of the 1% in the Global North. Imagine new medical care based on help going to those who need help the most rather than obscene wealth going to those who invest in the sickness industry.
Imagine citizens welcoming health professionals to walk through their homes because they do not fear being reported to the police and because they have seen mobilization after mobilization improve their lives rather than ensnare them in empty promises. Imagine a new society.
Don Fitz (email@example.com) is editor of Synthesis/Regeneration: A Magazine of Green Social Thought. He is Co-Coordinator of the Green Party of St. Louis and produces Green Time in conjunction with KNLC-TV. This article also appeared in BlackAgendaReport.com
1. My Spanish-English dictionary does not include “pesquizaje;” but Conner Gorry, Senior Editor of MEDICC Review says that Cuban health professionals use “pesquizaje activa” to mean “active screening” when they go door-to-door. Email message from Conner Gorry January 24, 2012.
2. Lázaro, P., Pérez, Antonio, Rivero, A., León, N., Díaz, M. & Pérez, Alina (Spring, 2008). Assessment of human health vulnerability to climate variability and change in Cuba. MEDICC Review, 10 (2), 1–9.
3. Dengue fever, A.D.A.M. Medical Encyclopedia. PubMed Health. Retrieved on February 6, 2012 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002350/
4. Dengue hemorrhagic fever, A.D.A.M. Medical Encyclopedia. PubMed Health. Retrieved on February 6, 2012 from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002349/
5. Vanlerberghe, V., Toledo, M.E., Rodriguez, M., Gómez, D., Baly, A., Benitez, J.R., & Van der Stuyft, P. (Winter 2010). Community involvement in dengue vector control: Cluster randomized trial. MEDICC Review, 12 (1), 41–47.
6. Whiteford, L.M., & Branch, L.G. (2008). Primary Health Care in Cuba: The Other Revolution. Lanham: Rowman & Littlefield Publishers, Inc.
7. Fitz, D. (March 2011). The Latin American School of Medicine today: ELAM,” Monthly Review, 62 (10) 50–62.
8. Medical Education Cooperation with Cuba. Retrieved February 6, 2012 from http://www.medicc.org/ns/index.php?s=3&p=3.
9. Guzmán, M.G. & Kouri, G. (2008). Dengue haemorrhagic fever integral hypothesis: Confirming observations, 1987–2007. Transactions of the Royal Society of Tropical Medicine and Hygiene. 102, 522–523.
10. Peláez, O., Sánchez, L, Más, P., Pérez, S., Kouri, G. & Guzmán, M. (April 2011). Prevalence of febrile syndromes in dengue surveillance, Havana City, 2007. MEDICC Review, 13 (2),47–51.
11. Díaz, C., Torres, Y., de la Cruz, A., Álvarez, A., Piquero, M., Valero, A. & Fuentes, O. (2009). Estrategía intersectoral y participativa con enfoque de ecosalud para la prevención de la transmisión de dengue en el nivel local. Cadernos Saúde Pública, 25 (Supl. 1), S59S70. http://dx.doi.org/10.1590/S0102-311×2009001300006