52

■Bio-mathematics, Statistics and Nano-Technologies: Mosquito Control Strategies

Entomological studies must not only be carried out to provide a practical answer to

clearly defined control-oriented research questions when data is unavailable or inadequate.

Entomological studies are also important in the estimation the expected impact of the var-

ious control measures. This helps to decide whether some measures are more useful than

others and whether some control measures are dangerous to implement (AFPM 2002).

4.12

MOSQUITO SURVEILLANCE AND COLLECTION

Collecting and evaluating information on adult mosquitos is important for decision-

making on deployment of appropriate control activities. The association between species of

mosquitos can provide clue to an understanding their biology and their role in the transmis-

sion of pathogen. Adult collections are most frequently conducted because adult mosquitos

are generally easier to survey, collect and identify, than the immature stages. A trapping

device is the most common and the simplest tool for the collection of mosquitos, mainly

for its surveillance, vector relative density, abundance and its control (Cameron & Russell

2005). Collection of mosquitos could be performed from 18:00 to 06:00 for the landing

and the resting catch and the same period time for the CDC light traps baited with dry ice.

The three main collections methods and other methods of mosquito collection use in other

studies by other authors are shown in the pictures and paragraphs listed below:

• CDC-light traps baited/augmented with CO2

• Human landing catch or bare lag catch and

• Resting catch

4.12.1

Light traps

Light traps are limited to gathering data on density and species composition of noctur-

nal adult mosquito species that are attracted to light. Some Anopheles and Aedes mosquitos

are poorly attracted to light; therefore, light traps are ineffective in collecting these species.

Although light traps are generally not recommended for use in collecting these genera,

some Aedes are strongly attracted to light traps (e.g., Ae. vexans, Oc. sollicitans and Ae.

taeniorhynchus) (WHO 1975).

Because of these behavioral differences, other of adult mosquito collection methods

(e.g., resting stations or landing counts) are needed to obtain a valid index of the total

population. A variety of light trap types exist. Wide differences in capture efficiency have

been noted between species due to differences in their reactions to light. Some species are

caught in great numbers while others are rarely taken even though they may be plentiful in

the vicinity (e.g., Ae. aegypti mosquitos).

Therefore, to increase their effectiveness, various modifications have been added such

as CO2 or dry ice and other components of host odor. The established role of CO2 as a

mosquito attractant (Service 1993, Cameron & Russell 2005) makes it feasible to use as a

standard in the sampling of mosquito population. Vythilingam et al. (1992) reported that