Abstract:
There is a long and widely held view that Aedes aegypti
(Linnaeus) and Ae. albopictus Skuse (Diptera: Culicidae),
the principal mosquito vectors of arboviruses causing yellow
fever, dengue, and chikungunya, oviposit and undergo
pre-imaginal development only in freshwater collections
near human habitations (Barraud 1934, Weaver and
Reisen 2010, Walter Reed Biosytematics Unit 2012, World
Health Organization 2009). Larval source reduction efforts
worldwide, therefore, focus on freshwater habitats of the two
vectors. However, Ae. aegypti and the closely related arboviral
vector Ae. albopictus were recently shown to also undergo
pre-imaginal development in brackish water of up to 15 ppt
salt (water with <0.5 ppt or parts per thousand salt is fresh,
0.5–30 ppt salt brackish, and >30 ppt salt saline) in discarded
food and beverage containers, as well as abandoned wells and
boats, along the coast of the Batticaloa and Jaffna districts in
tropical Sri Lanka (Ramasamy et al. 2011). Dengue is endemic
to Sri Lanka with 28,473 cases and 185 deaths in 2011. There
were 400 dengue cases with four deaths and 1,693 cases with
11 deaths, respectively, in 2011 in the Jaffna and Batticaloa
districts of the country. The Jaffna district also experienced
an epidemic of chikungunya in 2006-2007 (Surendran et
al. 2007). Dengue is of global health concern because of its
increasing incidence and spread, associated mortality and
morbidity, and the lack of a specific drug or vaccine (World
Health Organization 2009). Furthermore, Ae. albopictus has
adapted to temperate zones to transmit chikungunya and
dengue in Europe (Cavrini et al. 2009, Rezza et al. 2007, La
Ruche et al. 2010). Climate change can increase the future
global incidence and spread of dengue and other arboviral
diseases transmitted by Ae. aegypti and Ae. albopictus (Hales
et al. 2002, Ramasamy and Surendran 2011, 2012, Reiter
2001,Weaver and Reisen 2010).
