Limits...
Comparative evaluation of the Ifakara tent trap-B, the standardized resting boxes and the human landing catch for sampling malaria vectors and other mosquitoes in urban Dar es Salaam, Tanzania.

Sikulu M, Govella NJ, Ogoma SB, Mpangile J, Kambi SH, Kannady K, Chaki PC, Mukabana WR, Killeen GF - Malar. J. (2009)

Bottom Line: Species, respectively.SRBs exhibited poor sensitivity for both mosquito taxa and are not recommended in this setting.However, this protocol is affordable and effective for routine use of the ITT-B under programmatic conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Zoology, University of Nairobi, Nairobi, Kenya. maggysikulu@yahoo.com

ABSTRACT

Background: Frequent, sensitive and accurate sampling of Anopheles mosquitoes is a prerequisite for effective management of malaria vector control programmes. The most reliable existing means to measure mosquito density is the human landing catch (HLC). However, the HLC technique raises major ethical concerns because of the necessity to expose humans to vectors of malaria and a variety of other pathogens. Furthermore, it is a very arduous undertaking that requires intense supervision, which is severely limiting in terms of affordability and sustainability.

Methods: A community-based, mosquito sampling protocol, using the Ifakara tent trap-B (ITT-B) and standardized resting boxes (SRB), was developed and evaluated in terms of the number and sample composition of mosquitoes caught by each, compared to rigorously controlled HLC. Mosquitoes were collected once and three times every week by the HLC and the alternative methods, respectively, in the same time and location.

Results: Overall, the three traps caught 44,848 mosquitoes. The ITT-B, HLC and SRB caught 168, 143 and 46 Anopheles gambiae s.l. as well as 26,315, 13,258 and 4,791 Culex species respectively. The ITT-B was three- and five-times cheaper than the HLC per mosquito caught for An. gambiae and Cx. Species, respectively. Significant correlations between the numbers caught by HLC and ITT-B were observed for both An. gambiae s.l. (P < 0.001) and Cx. species (P = 0.003). Correlation between the catches with HLC and SRB were observed for Cx. species (P < 0.001) but not An. gambiae s.l. (P = 0.195), presumably because of the low density of the latter. Neither ITT-B nor SRB exhibited any obvious density dependence for sampling the two species.

Conclusion: SRBs exhibited poor sensitivity for both mosquito taxa and are not recommended in this setting. However, this protocol is affordable and effective for routine use of the ITT-B under programmatic conditions. Nevertheless, it is recommended that the trap and the protocol be evaluated further at full programmatic scales to establish effectiveness under fully representative conditions of routine practice.

Show MeSH

Related in: MedlinePlus

Photographs of the standardized resting boxes (SRB) used in this study. Panels A and B illustrate how the boxes are made, panel C demonstrates the way to install them, and panel D demonstrates how to recover resting mosquitoes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2734863&req=5

Figure 1: Photographs of the standardized resting boxes (SRB) used in this study. Panels A and B illustrate how the boxes are made, panel C demonstrates the way to install them, and panel D demonstrates how to recover resting mosquitoes.

Mentions: Elsewhere, resting boxes have been used to sample mosquitoes, relying on the widely observed phenomenon that they congregate in diurnal resting places which are dark and cool [9]. Boxes are generally placed on the ground with the opening facing west to minimize the influence of direct sunlight during the early part of the day. In well-shaded areas, the exact direction of the open end becomes less important [2,7,9]. It has been shown that female mosquitoes generally prefer larger and natural resting sites over smaller and artificial resting sites, respectively [10] and that in most cases the numbers of mosquitoes collected do not correlate with the results of host-seeking collections baited with humans [11]. This study investigated the ability of these boxes as outdoor devices for sampling host-seeking mosquitoes in urban Dar es Salaam where they had never been assessed before (Figure 1).


Comparative evaluation of the Ifakara tent trap-B, the standardized resting boxes and the human landing catch for sampling malaria vectors and other mosquitoes in urban Dar es Salaam, Tanzania.

Sikulu M, Govella NJ, Ogoma SB, Mpangile J, Kambi SH, Kannady K, Chaki PC, Mukabana WR, Killeen GF - Malar. J. (2009)

Photographs of the standardized resting boxes (SRB) used in this study. Panels A and B illustrate how the boxes are made, panel C demonstrates the way to install them, and panel D demonstrates how to recover resting mosquitoes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2734863&req=5

Figure 1: Photographs of the standardized resting boxes (SRB) used in this study. Panels A and B illustrate how the boxes are made, panel C demonstrates the way to install them, and panel D demonstrates how to recover resting mosquitoes.
Mentions: Elsewhere, resting boxes have been used to sample mosquitoes, relying on the widely observed phenomenon that they congregate in diurnal resting places which are dark and cool [9]. Boxes are generally placed on the ground with the opening facing west to minimize the influence of direct sunlight during the early part of the day. In well-shaded areas, the exact direction of the open end becomes less important [2,7,9]. It has been shown that female mosquitoes generally prefer larger and natural resting sites over smaller and artificial resting sites, respectively [10] and that in most cases the numbers of mosquitoes collected do not correlate with the results of host-seeking collections baited with humans [11]. This study investigated the ability of these boxes as outdoor devices for sampling host-seeking mosquitoes in urban Dar es Salaam where they had never been assessed before (Figure 1).

Bottom Line: Species, respectively.SRBs exhibited poor sensitivity for both mosquito taxa and are not recommended in this setting.However, this protocol is affordable and effective for routine use of the ITT-B under programmatic conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Zoology, University of Nairobi, Nairobi, Kenya. maggysikulu@yahoo.com

ABSTRACT

Background: Frequent, sensitive and accurate sampling of Anopheles mosquitoes is a prerequisite for effective management of malaria vector control programmes. The most reliable existing means to measure mosquito density is the human landing catch (HLC). However, the HLC technique raises major ethical concerns because of the necessity to expose humans to vectors of malaria and a variety of other pathogens. Furthermore, it is a very arduous undertaking that requires intense supervision, which is severely limiting in terms of affordability and sustainability.

Methods: A community-based, mosquito sampling protocol, using the Ifakara tent trap-B (ITT-B) and standardized resting boxes (SRB), was developed and evaluated in terms of the number and sample composition of mosquitoes caught by each, compared to rigorously controlled HLC. Mosquitoes were collected once and three times every week by the HLC and the alternative methods, respectively, in the same time and location.

Results: Overall, the three traps caught 44,848 mosquitoes. The ITT-B, HLC and SRB caught 168, 143 and 46 Anopheles gambiae s.l. as well as 26,315, 13,258 and 4,791 Culex species respectively. The ITT-B was three- and five-times cheaper than the HLC per mosquito caught for An. gambiae and Cx. Species, respectively. Significant correlations between the numbers caught by HLC and ITT-B were observed for both An. gambiae s.l. (P < 0.001) and Cx. species (P = 0.003). Correlation between the catches with HLC and SRB were observed for Cx. species (P < 0.001) but not An. gambiae s.l. (P = 0.195), presumably because of the low density of the latter. Neither ITT-B nor SRB exhibited any obvious density dependence for sampling the two species.

Conclusion: SRBs exhibited poor sensitivity for both mosquito taxa and are not recommended in this setting. However, this protocol is affordable and effective for routine use of the ITT-B under programmatic conditions. Nevertheless, it is recommended that the trap and the protocol be evaluated further at full programmatic scales to establish effectiveness under fully representative conditions of routine practice.

Show MeSH
Related in: MedlinePlus