This Caribbean country has succeeded in controlling or eliminated most NTDs. Dr. Dave Chadee, Professor of Environmental Health at the University of the West Indies, shares his vision about this success story, and highlights ideas that can be applied in other countries where the Neglected Tropical Diseases Initiative for LAC is implementing several projects.
Dr. Chadee, what is the situation regarding NTDs in Trinidad and Tobago?
The situation regarding NTDs in my country is quite different from that of our neighbor’s. The country has eliminated lymphatic filariasis (LF) as well as malaria, and leprosy has been reduced to less than 1 case in every 100,000 inhabitants so it is no longer considered a major public health problem. We have also reduced the incidence of hookworms and recent surveys have not found cases of this infection. Today, the NTDs that are still considered a real challenge are yellow fever, which still persists in some pockets in forested areas (a zoonosis), and dengue, the most extensive and problematic vector-borne disease in Trinidad and Tobago and the Caribbean region.
In your opinion, what are the main factors that have helped control and eliminate these diseases in the country?
Well, first of all the fact that Trinidad and Tobago has an universal, free to all health care system that has helped in controlling or eliminating most of the local and imported diseases. This is an advantage compared to other countries in the Caribbean region, because offering free treatments to all for any NTD makes it easier for people to seek help when they need it, no matter their ability to pay for these services and whether they are nationals or non nationals.
I also think that having staff that have received specific training on NTDs is key, and not only do they need to acquire the knowledge: they need to keep informed of new developments in their field by receiving updates or refresher training.
Another success story for the country involves the strategy against NTDs – which involves continuing monitoring and evaluation activities. We know of programs that have implemented wonderful strategies but did not incorporate internal audits to check their effectiveness, strengths and weaknesses over time, significantly reducing the efficacy of the programs.
Last but not least, I believe that the political support of local authorities is key, both for the implementation of effective programs and to keep morale high among health workers. NTD work can be tedious because it is a battle that is never complete, so keeping the morale of the teams high, making workers feel appreciated, is very important.
What is the importance of vector management in the fight against NTDs?
Our experience has demonstrated that integrated vector management can help combat these diseases more effectively. At my university we have developed vector control strategies that are effective against Culex quinquefasciatus and other container breeding mosquitoes. Also, our research demonstrates that integrated vector management can be useful if used together with mass drug administration programs, and can help raise awareness about LF and other NTDs among communities.
Based on your latest research about transmission of LF, what are the changes you have observed in the habits of the Culex mosquito in the last years?
Based on my research, there is evidence that the blood feeding times of the Culex quinquefasciatus mosquito, the main vector for the transmission of LF, have shifted significantly. Previous studies showed the peak biting times in Trinidad and Tobago was between 10 pm and 3 am. Now we are finding a bimodal pattern with an early peak between 7 and 9 pm, as well as the 10-3am peak. This shift may be due to any of several factors like the use of air conditioning and fans in the household and the change of light regimens in cities such as the use of indoor lights and security lights from dusk to dawn. This means that the Culex mosquitoes have access to people between 7 and 11 pm, when they are relaxing at home and are likely to be casually dressed and exposing larger skin surface area to foraging mosquitoes. In addition, our preliminary study shows more biting in areas around the legs and arms, thereby increasing the possibility of LF transmission at an earlier time during the night than previously thought. We think it is important to take these factors into account when designing programs to fight LF and other vector-born NTDs.
Dr. Dave D. Chadee is a Professor of Environmental Health in the Department of Life Sciences, UWI. His breakthrough research includes the development of the Xenomonitoring/PCR approach to Lymphatic filariasis, a new assay method for detecting mosquito preferences, the pupal index for dengue epidemiology and control, detected and eradicated two malaria outbreaks in Trinidad and the paper published in Science entitled, Genetics: a breakthrough for global public health.
Prof. Chadee has published over 200 papers and book chapters and has numerous collaborations in the USA and the UK. Prof. Chadee is a graduate of Naparima College, Trinidad, Dalhousie University (BSc Hons.), The University of the West Indies (MPhil) and the University of Dundee (PhD, M.PH, DSc).