Strengthening the Control of Mosquito Vectors in Cabo Verde

■289

A comparative analysis (Kruskal-Wallis test) of the turnover of OVTs, at the four points

in each location, shows that only location 6 (P = 0,012) showed a statistically significant

difference (P < 0.05) in the number of eggs found at each point. After applying the Tukey

test at location 6, it observed a significant difference for eggs collected between points A

and B (P < 0.05). As a whole, the result of the comparative analysis demonstrated a distri-

bution of OVTs, by locations, without influence of the position of OVTs in the oviposition

of gravid females of Ae. aegypti.

Analyzing the POI obtained according to the type of substance tested in the OVTs, the

differences were not appreciable except for the OVTs with salt in relation to the control

(Figure 18.3 A). For the DEI the differences were notable. The OVTs with Bti + infusion

collected a greater amount of Ae. aegypti eggs (20233) with a DEI of 229.92. The OVTs

with table salt collected the lowest number of eggs (1508), having recorded a DEI of 16.39

(18.3 B).

Comparison of the different OVTs tested with the Control OVT (Kruskal-Wallis test)

in relation to the number of eggs collected during the study period demonstrates that there

is a statistically significant difference (P < 0.05) between them and the Control OVT (P

= < 0.001). Regarding temperature and monthly relative humidity, there were no major

variations during the study period, with mean values of 26.9 ^oC and 82% respectively.

Average monthly rainfall was 37.7 mm, occurring almost entirely in September (108.8

mm). There is no significant relationship between climate data and infestation rates (POI

and DEI).

18.3.4

Discussion

In this study, it was observed that the adaptation of the ovitrap from the model devel-

oped by [21] is promising for monitoring Ae. aegypti in the city of Praia, since the use of

acacia infusion + Bti in the OVT collected twice as many eggs when compared to the use

of tap water alone. The use of acacia infusion in OVTs is an innovation, used for the first

time (in oviposition traps) in this study. The use of table salt in OVT worked as a repellent

for female Ae. aegypti mosquitos in Cabo Verde.

18.3.5

Conclusion

Of the substances tested in ovitraps, Bti and Bti+infusion work as attractants of Ae.

aegypti from the city of Praia, whilst table salt having been verified as having an effect

of repellency. The use of biological larvicide Bti, in ovitraps, allowed the permanence of

OVTs in the field, safely, for at least 15 days. Monitoring with ovitraps in the Palmarejo

neighborhood showed that it had a high infestation of Ae. aegypti, during the study period.

18.4

PILOT STUDY II

18.4.1

BR-OVT evaluation as a tool for monitoring mosquito vectors in Cabo Verde

Cabo Verde has a record of eleven species of Culicidae in the country, two of which

are recognized vectors, Ae. aegypti and Anopheles arabiensis [22, 23]. This fact does not

mean that in the future other potential vector species, such as Culex pipiens and Culex