Effect of village-wide use of long-lasting insecticidal nets on visceral Leishmaniasis vectors in India and Nepal: a cluster randomized trial

Albert Picado, Murari L Das, Vijay Kumar, Shreekant Kesari, Diwakar S Dinesh, Lalita Roy, Suman Rijal, Pradeep Das, Mark Rowland, Shyam Sundar, Marc Coosemans, Marleen Boelaert, Clive R Davies, Albert Picado, Murari L Das, Vijay Kumar, Shreekant Kesari, Diwakar S Dinesh, Lalita Roy, Suman Rijal, Pradeep Das, Mark Rowland, Shyam Sundar, Marc Coosemans, Marleen Boelaert, Clive R Davies

Abstract

Background: Visceral leishmaniasis (VL) control in the Indian subcontinent is currently based on case detection and treatment, and on vector control using indoor residual spraying (IRS). The use of long-lasting insecticidal nets (LN) has been postulated as an alternative or complement to IRS. Here we tested the impact of comprehensive distribution of LN on the density of Phlebotomus argentipes in VL-endemic villages.

Methods: A cluster-randomized controlled trial with household P. argentipes density as outcome was designed. Twelve clusters from an ongoing LN clinical trial--three intervention and three control clusters in both India and Nepal--were selected on the basis of accessibility and VL incidence. Ten houses per cluster selected on the basis of high pre-intervention P. argentipes density were monitored monthly for 12 months after distribution of LN using CDC light traps (LT) and mouth aspiration methods. Ten cattle sheds per cluster were also monitored by aspiration.

Findings: A random effect linear regression model showed that the cluster-wide distribution of LNs significantly reduced the P. argentipes density/house by 24.9% (95% CI 1.80%-42.5%) as measured by means of LTs.

Interpretation: The ongoing clinical trial, designed to measure the impact of LNs on VL incidence, will confirm whether LNs should be adopted as a control strategy in the regional VL elimination programs. The entomological evidence described here provides some evidence that LNs could be usefully deployed as part of the VL control program.

Trial registration: ClinicalTrials.gov CT-2005-015374.

Trial registration: ClinicalTrials.gov NCT00318721.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1. Location of the 12 clusters,…
Figure 1. Location of the 12 clusters, 6 in Muzaffarpur district, India and 6 in Sunsari district, Nepal selected for the entomological trial.
Intervention and control clusters are identified with a circle and a triangle respectively.
Figure 2. Flow diagram of clusters and…
Figure 2. Flow diagram of clusters and households (and cattle sheds) through study.
The upper part corresponds to the cluster selection for the full KALANET clinical trial and the lower part details the progress for the subset used in the entomological trial described in this paper.
Figure 3. Monthly geometric mean (GM) of…
Figure 3. Monthly geometric mean (GM) of total P. argentipes/LT/house for intervention (solid line) and control (dotted line) clusters.
(A) India and (B) Nepal. The arrow indicates the time of intervention (distribution of long lasting insecticidal nets).

References

    1. Desjeux P. Leishmaniasis: current situation and new perspectives. Comparative Immunology, Microbiology and Infectious Diseases. 2004;27:305–318.
    1. Dinesh DS, Kar SK, Kishore K, Palit A, Verma N, et al. Screening sandflies for natural infection with Leishmania donovani, using a non-radioactive probe based on the total DNA of the parasite. Ann Trop Med Parasitol. 2000;94:447–451.
    1. Joshi AB, Bhatt LR, Regmi S, Ashford R. An assessment of the effectiveness of insecticide spray in the control of visceral leishmaniasis in Nepal. Journal of the Nepal Health Research Council. 2003;1:1–6.
    1. Mondal D, Alam MS, Karim Z, Haque R, Boelaert M, et al. Present situation of vector-control management in Bangladesh: A wake up call. Health Policy. 2008;87:369–376.
    1. Ostyn B, Vanlerberghe V, Picado A, Dinesh DS, Sundar S, et al. Vector control by insecticide-treated nets in the fight against visceral leishmaniasis in the Indian subcontinent, what is the evidence? Trop Med Int Health 2008
    1. Shrestha SL. Seasonal distribution of phlebotomine sandflies - vector of visceral leishmaniasis. Journal of Nepal Medical Association. 1994;32:237–246.
    1. Das ML, Karki P, Koirala S, Parija SC. Entomological study of sand fly vector of kala-azar in eastern Nepal. Health Renaissance. 2007;1:26–30.
    1. Dinesh DS, Ranjan A, Palit A, Kishore K, Kar SK. Seasonal and nocturnal landing/biting behaviour of Phlebotomus argentipes (Diptera: Psychodidae). Ann Trop Med Parasitol. 2001;95:197–202.
    1. Moosa-Kazemi SH, Yaghoobi-Ershadir MR, Akhavan AA, Abdoli H, Zahraei-Ramazani AR, et al. Deltamethrin-impregnated bed nets and curtains in an anthroponotic cutaneous leishmaniasis control program in northeastern Iran. Ann Saudi Med. 2007;27:6–12.
    1. Nadim A, Motabar B, Houshmand B, Keyghobadi K, Aflatonian M. Evaluation of pyrethroid impregnated bednets for control of anthroponotic cutaneous leishmaniasis in Bam (Islamic Republic of Iran) Geneva: WHO; 2000. WHO/LEISH/95.37 WHO/LEISH/95.37.
    1. Yaghoobi-Ershadi MR, Moosa-Kazemi SH, Zahraei-Ramazani AR, Jalai-Zand AR, Akhavan AA, et al. Evaluation of deltamethrin-impregnated bed nets and curtains for control of zoonotic cutaneous leishmaniasis in a hyperendemic area of Iran. Bull Soc Pathol Exot. 2006;99:43–48.
    1. Elnaiem DA. Use of pyrethroid impregnated bednets for the control of visceral leishmaniasis in eastern Sudan. Geneva: WHO; 1996. WHO ID L3/1881/47 WHO ID L3/1881/47.
    1. Tayeh A, Jalouk L, Al-Kahaimi A. A cutaneous leishmaniasis control trial using pyrethroid-impregnated bednets in villages near Aleppo, Syria. Geneva: WHO; 1997. WHO/LEISH/97.41 WHO/LEISH/97.41.
    1. Alten B, Caglar SS, Simsek FM, Kaynas S. Effect of insecticide-treated bednets for malaria control in Southeast Anatolia-Turkey. J Vector Ecol. 2003;28:97–107.
    1. Emami MM, M. Y, Bashardoust N. Impact of Olyset long lasting nets to control transmission of anthroponotic cutaneous leishmaniasis in central Iran. Geneva: WHO; 2004. Project No SGS04-76 Project No SGS04-76.
    1. Jalouk L, Al Ahmed M, Gradoni L, Maroli M. Insecticide-treated bednets to prevent anthroponotic cutaneous leishmaniasis in Aleppo Governorate, Syria: results from two trials. Trans R Soc Trop Med Hyg. 2007;101:360–367.
    1. Ritmeijer K, Davies C, van Zorge R, Wang SJ, Schorscher J, et al. Evaluation of a mass distribution programme for fine-mesh impregnated bednets against visceral leishmaniasis in eastern Sudan. Trop Med Int Health. 2007;12:404–414.
    1. Curtis CF, Maxwell CA, Magesa SM, Rwegoshora RT, Wilkes TJ. Insecticide-treated bed-nets for malaria mosquito control. J Am Mosq Control Assoc. 2006;22:501–506.
    1. Maxwell CA, Msuya E, Sudi M, Njunwa KJ, Carneiro IA, et al. Effect of community-wide use of insecticide-treated nets for 3–4 years on malarial morbidity in Tanzania. Trop Med Int Health. 2002;7:1003–1008.
    1. Soremekun S, Maxwell C, Zuwakuu M, Chen C, Michael E, et al. Measuring the efficacy of insecticide treated bednets: the use of DNA fingerprinting to increase the accuracy of personal protection estimates in Tanzania. Trop Med Int Health. 2004;9:664–672.
    1. Hassan MM, Elraba'a FM, Ward RD, Maingon RD, Elnaiem DA. Detection of high rates of in-village transmission of Leishmania donovani in eastern Sudan. Acta Trop. 2004;92:77–82.
    1. Basak B, Kundu M, Tandon N. Observation on host preference of Phlebotomus argentipes in district South-24-Parganas, West Bengal, India. J Commun Dis. 1995;27:122–123.
    1. Ghosh KN, Bhattacharya A, Ghosh TN. Blood meal analysis of Phlebotomus argentipes in eight districts of West Bengal. J Commun Dis. 1990;22:67–71.
    1. Mukhopadhyay AK, Chakravarty AK. Bloodmeal preference of Phlebotomus argentipes & Ph. papatasi of north Bihar, India. Indian J Med Res. 1987;86:475–480.
    1. Hayes RJ, Bennett S. Simple sample size calculation for cluster-randomized trials. Int J Epidemiol. 1999;28:319–326.
    1. Jana-Kara BR, Jihullah WA, Shahi B, Dev V, Curtis CF, et al. Deltamethrin impregnated bednets against Anopheles minimus transmitted malaria in Assam, India. J Trop Med Hyg. 1995;98:73–83.
    1. Yadav RS, Sampath RR, Sharma VP. Deltamethrin treated bednets for control of malaria transmitted by Anopheles culicifacies (Diptera: Culicidae) in India. J Med Entomol. 2001;38:613–622.
    1. Dinesh DS, Das P, Picado A, Davies C, Speybroeck N, et al. Long-lasting insecticidal nets fail at household level to reduce abundance of sandfly vector Phlebotomus argentipes in treated houses in Bihar (India). Trop Med Int Health. 2008;13:953–958.
    1. Ghosh K, Mukhopadhyay J, Desai MM, Senroy S, Bhattacharya A. Population ecology of Phlebotomus argentipes (Diptera: Psychodidae) in West Bengal, India. J Med Entomol. 1999;36:588–594.
    1. Dinesh DS, Das P, Picado A, Davies C, Speybroeck N, et al. The efficacy of indoor CDC light traps for collecting the sandfly Phlebotomus argentipes, vector of Leishmania donovani. Med Vet Entomol. 2008;22:120–123.
    1. Mondal D, Singh SP, Kumar N, Joshi A, Sundar S, et al. Visceral leishmaniasis elimination programme in India, bangladesh, and Nepal: reshaping the case finding/case management strategy. PLoS Negl Trop Dis. 2009;3:e355.

Source: PubMed

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