Dengue in HaitiPosted on by
There is arguably one place that was more affected by the January 2010 earthquake than Port-au-Prince, and that is Léogâne. A low-lying coastal town about a two-hour drive from the capital, Léogâne was the epicenter of the earthquake that devastated Haiti. As part of my Epidemic Intelligence Service (EIS) fieldwork, I have been investigating a possible outbreak of dengue among aid workers in Léogâne.
Since the earthquake, Léogâne has become a site of ongoing infrastructure development, with visible construction of new roads, and water and sanitation projects. The town has also become a hub for non-governmental organizations (NGOs); within this small town one can see Médecins Sans Frontières (MSF, or Doctors Without Borders) working next door to International Federation of Red Cross and Red Crescent Societies (IFRC), Red-Cross Germany, Red-Cross Spain, and Red-Cross Swiss. Each organization has its own site within Léogâne. Some NGOs are housed within temporary buildings and others are housed in small compounds that contain office buildings, clinics, and residences for workers. The NGO workers in Léogâne include Haitians and expatriates from all over the world. All of these NGO workers, regardless of their origin, face the threat of mosquito-borne diseases, including malaria, lymphatic filariasis, and dengue.
Dengue is a virus transmitted by mosquitoes. Once bitten, a person can experience symptoms such as high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). While the majority (70%) of people infected with dengue experience no clinical symptoms at all, they are still able to infect mosquitoes that can then infect other people. A small percentage of people (1-5%) with symptoms of dengue develop severe disease. Dengue is thought to cause approximately 25,000 deaths every year worldwide.
There are two main mosquitoes that are responsible for transmitting dengue virus: Aedes aegypti and Aedes albopictus. Outbreaks of dengue occur primarily in the endemic regions of the tropics and subtropics where Aedes aegypti and albopictus mosquitoes live. While a lot is known about dengue activity in several Caribbean countries, like Puerto Rico and Cuba, very little is known about dengue in Haiti.
In October 2012, a doctor from IFRC contacted the Haiti Ministry of Health and CDC to report that an unusually high number of NGO workers in Haiti—and primarily in Léogâne—had been diagnosed with dengue in the previous 6 months. Six of these NGO workers had been evacuated out of Haiti in order to receive more advanced medical care. In response to this alert, the Haitian Ministry of Health together with CDC launched an investigation in Léogâne. In addition to myself, our team included residents from Haiti’s Field Epidemiology Training Program, epidemiologists from CDC-Haiti, and an Epidemic Intelligence Service officer and entomologist from CDC’s Dengue Branch in Puerto Rico. For about 2 weeks from late November through early December 2012, our team collected blood samples and administered questionnaires to both expatriate and Haitian NGO staff in order to determine the number of people with recent dengue virus infection and what factors put them at greater risk. Blood samples were sent from Haiti’s National Public Health Laboratory to CDC’s Dengue Branch laboratory in Puerto Rico for testing. We also provided educational materials to NGO workers that explained how to prevent dengue virus infection, and we conducted environmental inspections of residential and work sites to look for mosquitoes that carry dengue virus.
During our investigation, we observed high numbers of mosquitoes at all the worksites and residences we visited. The majority of these mosquitoes were Aedes aegypti. Buckets and tires containing water were the most common habitats for immature mosquitoes that we saw during our environmental inspections. During our site visits, we educated NGO workers about the importance of emptying out containers with pooled water, and we stressed the importance of creating proper drainage for any outside containers. In addition, because the mosquitoes that transmit dengue primarily bite during the day, we stressed the importance of using mosquito repellent containing 20-30% DEET throughout the day in order to prevent insect bites.
Our investigation of nearly 200 NGO workers revealed that one in ten participants had been infected with dengue virus in the last 3 months. Both Haitians and expatriates had been recently infected. Our team is in the process of sharing the preliminary results of our investigation with the Haitian government and all of the NGOs that participated in the investigation. We are emphasizing that greater efforts should be made to educate all NGO workers on mosquito-bite prevention practices, and that community-wide work should be undertaken to reduce mosquito-producing habitats in and around workplaces and residences. Because no vaccine is currently available to prevent dengue, avoiding mosquito bites is the most effective protection against infection. In addition, doctors and nurses should be aware that dengue virus infections occur in both Haitians and expatriates in Haiti, and they should consider dengue as a possible diagnosis for patients who have flu-like symptoms.
Even though our investigation was mainly conducted in Léogâne, we know that dengue likely occurs throughout Haiti. Therefore, we hope that our recommendations from this investigation will be shared with NGOs and health workers throughout the country to help prevent future dengue infections.