Trial of pyrethroid impregnated bednets in an area of Tanzania holoendemic for malaria Part 1. Operational methods and acceptability

Njunwa, Kato J.; Lines, Jo; Magesa, Stephen; Mnzava, A.E.P.; Wilkes, T. J.; Alilio, Martin; Kivumbi, K.; Curtis, C. F.

doi:10.1016/0001-706x(91)90056-p

Cited by 56 publications

(31 citation statements)

References 7 publications

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“…Endorsement by a nationally respected authority added to the confidence of the users. Lambdacyalothrin-treated nets may cause flu-like symptoms in some people sleeping under them during the first few nights after treatment (Curtis 1991); Njunwa et al 1991;Miller et al 1995). The nets in this study were first used on the second night after treatment.…”

Section: Discussionmentioning

confidence: 99%

A new strategy for treating nets. Part 2: Users' perceptions of efficacy and washing practices and their implications for insecticide dosage

Miller

Jones

Ndunguru

et al. 1999

Tropical Med Int Health

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SummaryThe conventional way to treat a mosquito net with pyrethroid insecticide is to apply a standard dosage every 6-12 months, and to avoid washing the net until just before retreatment. In some places, nets are normally washed much more often than this, and it may then be more appropriate to apply smaller amounts of insecticide after each wash. The choice of strategy must take into account not only biological effectiveness, but also users' perceptions of this effectiveness and their net-washing habits. We used focus groups to compare users' responses to nets treated with different dosages and chemicals. One hundred current net users in urban Dares-Salaam were each given a net that had been pretreated either with permethrin (200 or 500 mg/m 2 ), or with lambdacyhalothrin (3 or 15 mg/m 2 ), or with water. Neither participants nor investigators knew which group had received which treatment. Focus group discussions were held after 2, 8 and 12 weeks. Participants greatly preferred treated nets. Low doses were perceived to be less effective, especially after 8 and 12 weeks. After 12 weeks most participants had washed their nets, despite requests to the contrary. Dirty nets were regarded as unhealthy and socially unacceptable. Few participants experienced side-effects or expressed fears about the safety of treatment. We conclude that asking people to refrain from washing their nets is unrealistic. A 'lowdose frequent-treatment' strategy of insecticide application may be more appropriate in the long run. At first, however, low doses give perceptibly inferior protection. An initial high (loading) dose, followed by frequent lower (maintenance) dosages, might solve this problem. keywords malaria, insecticide, pyrethroid, mosquito nets, user perceptions, Tanzania correspondence Dr

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Section: Discussionmentioning

confidence: 99%

A new strategy for treating nets. Part 2: Users' perceptions of efficacy and washing practices and their implications for insecticide dosage

Miller

Jones

Ndunguru

et al. 1999

Tropical Med Int Health

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“…Specific attention has to be paid to side-effects, which were more frequent with lambdacyhalothrin than with permethrin (Njunwa et al 1991). Although the side-effects may not be a health hazard, they can undermine the acceptance of the programme or lead to immediate washing of the net after impregnation, as observed in Nicaragua.…”

Section: Experiences With Impregnationmentioning

confidence: 99%

“…Information about the logistics and operational implications of bednet impregnation programs is still scarce (Snow et al 1988;Rozendaal 1989;Gyapong et al 1996;Marbiah et al 1994;Makemba et al 1995;Njunwa et al 1991) and the need for operational research has been stressed (Lengeler & Snow 1996;. The purpose of this paper is to describe the operational aspects encountered during bednet impregnation programmes in Nicaragua, Ecuador, Peru and Colombia.…”

Section: Introductionmentioning

confidence: 99%

Operational aspects of bednet impregnation for community‐based malaria control in Nicaragua, Ecuador, Peru and Colombia

Kroeger

Meyer

Mancheno

et al. 1997

Tropical Med Int Health

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SummaryCommunity intervention projects with pyrethroid (permethrin and lambdacyhalothrin) impregnated bednets and an accompanying community education programme were carried out in 6 malaria endemic areas on the Pacific coast of Nicaragua, Ecuador, Peru and Colombia as well as in the Peruvian Amazon basin. In this paper the operational aspects are analysed: bednet coverage, results of promotional activities for increased bednet use, the sale of low-cost bednets, techniques and difficulties with impregnation, acceptance of the programme (including washing of impregnated nets), side-effects, residual concentrations of the chemical in the nets, costs of the impregnation programme and insecticide resistance of the malaria vectors.We found that the local manufacture of bednets and their sale through village health workers, even in communities with low cash income, is a viable way of increasing bednet coverage; the impregnation of bednets is well accepted if villagers perceive a direct benefit; pretesting of the soaking capacity of different net materials should be done at central level; the instructions for the impregnation procedures of different net materials (cotton and synthetic) should be simple and unambiguous; very cheap thin net materials should be avoided, particularly in the case of lambdacyhalothrin impregnation; educational methods and/or promotion of dark-colour nets should be further tested in order to decrease the washing frequency of bednets at household level; in areas with early-biting mosquitoes further studies on the protective efficacy of bednets are necessary; careful monitoring of side-effects, particularly those of last-generation pyrethroids, is necessary; and the community-based impregnation programme is a powerful tool for strengthening community involvement in health actions.

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“…The highest of these doses is approximately what is now commonly used for net treatment; markedly higher doses tend to make net users sneeze (Njunwa et al 1991). At each of the doses tested, the resistance heterozygotes showed a knockdown rate that was distinctly lower than that of susceptibles, i.e.…”

mentioning

confidence: 94%

Can anything be done to maintain the effectiveness of pyrethroid–impregnated bednets against malaria vectors?

Curtis

Miller

Hodjati

et al. 1998

Phil. Trans. R. Soc. Lond. B

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Pyrethroid-treated bednets are the most promising available method of controlling malaria in the tropical world. Every e¡ort should be made to ¢nd methods of responding to, or preventing, the emergence of pyrethroid resistance in the Anopheles vectors. Some cases of such resistance are known, notably in An. gambiae in West Africa where the kdr type of resistance has been selected, probably because of the use of pyrethroids on cotton. Because pyrethroids are irritant to mosquitoes, laboratory studies on the impact of, and selection for, resistance need to be conducted with free-£ying mosquitoes in conditions that are as realistic as possible. Such studies are beginning to suggest that, although there is cross-resistance to all pyrethroids, some treatments are less likely to select for resistance than others are. Organophosphate, carbamate and phenyl pyrazole insecticides have been tested as alternative treatments for nets or curtains. Attempts have been made to mix an insect growth regulator and a pyrethroid on netting to sterilize pyrethroid-resistant mosquitoes that are not killed after contact with the netting. There seems to be no easy solution to the problem of pyrethroid resistance management, but further research is urgently needed.

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Trial of pyrethroid impregnated bednets in an area of Tanzania holoendemic for malaria Part 1. Operational methods and acceptability

Cited by 56 publications

References 7 publications

A new strategy for treating nets. Part 2: Users' perceptions of efficacy and washing practices and their implications for insecticide dosage

A new strategy for treating nets. Part 2: Users' perceptions of efficacy and washing practices and their implications for insecticide dosage

Operational aspects of bednet impregnation for community‐based malaria control in Nicaragua, Ecuador, Peru and Colombia

Can anything be done to maintain the effectiveness of pyrethroid–impregnated bednets against malaria vectors?

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