Exploring the potential of using cattle for malaria vector surveillance and control : a pilot study in western Kenya
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Biomed Central
Abstract
Background: Malaria vector mosquitoes with exophilic and zoophilic tendencies, or with a high acceptance of
alternative blood meal sources when preferred human blood-hosts are unavailable, may help maintain low but
constant malaria transmission in areas where indoor vector control has been scaled up. This residual transmission
might be addressed by targeting vectors outside the house. Here we investigated the potential of insecticide-treated
cattle, as routinely used for control of tsetse and ticks in East Africa, for mosquito control.
Methods: The malaria vector population in the study area was investigated weekly for 8 months using two different
trapping tools: light traps indoors and cattle-baited traps (CBTs) outdoors. The effect of the application of the
insecticide deltamethrin and the acaricide amitraz on cattle on host-seeking Anopheles arabiensis was tested
experimentally in field-cages and the impact of deltamethrin-treated cattle explored under field conditions on
mosquito densities on household level.
Results: CBTs collected on average 2.8 (95% CI: 1.8–4.2) primary [Anopheles gambiae (s.s.), An. arabiensis and
An. funestus (s.s.)] and 6.3 (95% CI: 3.6–11.3) secondary malaria vectors [An. ivulorum and An. coustani (s.l.)] per
trap night and revealed a distinct, complementary seasonality. At the same time on average only 1.4 (95% CI: 0.8–2.3)
primary and 1.1 (95% CI: 0.6–2.0) secondary malaria vectors were collected per trap night with light traps indoors.
Amitraz had no effect on survival of host-seeking An. arabiensis under experimental conditions but deltamethrin
increased mosquito mortality (OR 19, 95% CI: 7–50), but only for 1 week. In the field, vector mortality in association
with deltamethrin treatment was detected only with CBTs and only immediately after the treatment (OR 0.25, 95%
CI: 0.13–0.52).
Conclusions: Entomological sampling with CBTs highlights that targeting cattle for mosquito control has potential
since it would not only target naturally zoophilic malaria vectors but also opportunistic feeders that lack access to
human hosts as is expected in residual malaria transmission settings. However, the deltamethrin formulation tested
here although used widely to treat cattle for tsetse and tick control, is not suitable for the control of malaria vectors
since it causes only moderate initial mortality and has little residual activity.
Description
CITATION: Njoroge, M. M., et al. 2017. Exploring the potential of using cattle for malaria vector surveillance and control : a pilot study in western Kenya. Parasites & Vectors, 10:18, doi:10.1186/s13071-016-1957-8.
The original publication is available at https://parasitesandvectors.biomedcentral.com
The original publication is available at https://parasitesandvectors.biomedcentral.com
Keywords
Malaria -- Control, Cattle as carriers of disease -- Kenya, Malaria -- Transmission, Insecticides -- Research, Mosquitos -- Control
Citation
Njoroge, M. M., et al. 2017. Exploring the potential of using cattle for malaria vector surveillance and control : a pilot study in western Kenya. Parasites & Vectors, 10:18, doi:10.1186/s13071-016-1957-8