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Studies on mosquito biting risk among migratory rice farmers in rural south-eastern Tanzania and development of a portable mosquito-proof hut

View Article: PubMed Central - PubMed

ABSTRACT

Background: Subsistence rice farmers in south-eastern Tanzania are often migratory, spending weeks or months tending to crops in distant fields along the river valleys and living in improvised structures known as Shamba huts, not fully protected from mosquitoes. These farmers also experience poor access to organized preventive and curative services due to long distances. Mosquito biting exposure in these rice fields, relative to main village residences was assessed, then a portable mosquito-proof hut was developed and tested for protecting these migratory farmers.

Methods: Pair-wise mosquito surveys were conducted in four villages in Ulanga district, south-eastern Tanzania in 20 randomly-selected Shamba huts located in the distant rice fields and in 20 matched houses within the main villages, to assess biting densities and Plasmodium infection rates. A portable mosquito-proof hut was designed and tested in semi-field and field settings against Shamba hut replicas, and actual Shamba huts. Also, semi-structured interviews were conducted, timed-participant observations, and focus-group discussions to assess experiences and behaviours of the farmers regarding mosquito-bites and the mosquito-proof huts.

Results: There were equal numbers of mosquitoes in Shamba huts and main houses [RR (95% CI) 27 (25.1–31.2), and RR (95% CI) 30 (27.5–33.4)], respectively (P > 0.05). Huts having >1 occupant had more mosquitoes than those with just one occupant, regardless of site [RR (95% CI) 1.57 (1.30–1.9), P < 0.05]. Open eaves [RR (95% CI) 1.15 (1.08–1.23), P < 0.05] and absence of window shutters [RR (95% CI) 2.10 (1.91–2.31), P < 0.05] increased catches of malaria vectors. All Anopheles mosquitoes caught were negative for Plasmodium. Common night-time outdoor activities in the fields included cooking, eating, fetching water or firewood, washing dishes, bathing, and storytelling, mostly between 6 and 11 p.m., when mosquitoes were also biting most. The prototype hut provided 100% protection in semi-field and field settings, while blood-fed mosquitoes were recaptured in Shamba huts, even when occupants used permethrin-impregnated bed nets.

Conclusion: Though equal numbers of mosquitoes were caught between main houses and normal Shamba huts, the higher proportions of blood-fed mosquitoes, reduced access to organized healthcare and reduced effectiveness of LLINs, may increase vulnerability of the itinerant farmers. The portable mosquito-proof hut offered sufficient protection against disease-transmitting mosquitoes. Such huts could be improved to expand protection for migratory farmers and possibly other disenfranchised communities.

No MeSH data available.


Swai hut prototype. Picture showing the front (a) and side (b) views of the Swai hut prototype
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Fig4: Swai hut prototype. Picture showing the front (a) and side (b) views of the Swai hut prototype

Mentions: The main aim was to create a portable mosquito-proof hut prototype with the following essential characteristics: (1) easy to transport, (2) large enough to accommodate a migratory family of two adults and one child, (3) easy for one person to set up while in the field on his/her own, (4) robust and durable for long-term field use, (6) highly ventilated and (7) can be mounted on basic pedestals already being used by farmers in the study area (Fig. 1b, d). A tentative hut design to meet these features was proposed (Fig. 3), upon which the structural engineers at the partnering company (Elastic Product Manufacturing Company Limited, Tanzania), worked to create the final prototype. Construction was done based primarily on this original design, while also considering preferences suggested by the farmers during our interviews and focus-group discussions, as well as additional modifications from the expert engineers. The final prototype design, also called Swai hut is shown in Fig. 4.Fig. 3


Studies on mosquito biting risk among migratory rice farmers in rural south-eastern Tanzania and development of a portable mosquito-proof hut
Swai hut prototype. Picture showing the front (a) and side (b) views of the Swai hut prototype
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5120485&req=5

Fig4: Swai hut prototype. Picture showing the front (a) and side (b) views of the Swai hut prototype
Mentions: The main aim was to create a portable mosquito-proof hut prototype with the following essential characteristics: (1) easy to transport, (2) large enough to accommodate a migratory family of two adults and one child, (3) easy for one person to set up while in the field on his/her own, (4) robust and durable for long-term field use, (6) highly ventilated and (7) can be mounted on basic pedestals already being used by farmers in the study area (Fig. 1b, d). A tentative hut design to meet these features was proposed (Fig. 3), upon which the structural engineers at the partnering company (Elastic Product Manufacturing Company Limited, Tanzania), worked to create the final prototype. Construction was done based primarily on this original design, while also considering preferences suggested by the farmers during our interviews and focus-group discussions, as well as additional modifications from the expert engineers. The final prototype design, also called Swai hut is shown in Fig. 4.Fig. 3

View Article: PubMed Central - PubMed

ABSTRACT

Background: Subsistence rice farmers in south-eastern Tanzania are often migratory, spending weeks or months tending to crops in distant fields along the river valleys and living in improvised structures known as Shamba huts, not fully protected from mosquitoes. These farmers also experience poor access to organized preventive and curative services due to long distances. Mosquito biting exposure in these rice fields, relative to main village residences was assessed, then a portable mosquito-proof hut was developed and tested for protecting these migratory farmers.

Methods: Pair-wise mosquito surveys were conducted in four villages in Ulanga district, south-eastern Tanzania in 20 randomly-selected Shamba huts located in the distant rice fields and in 20 matched houses within the main villages, to assess biting densities and Plasmodium infection rates. A portable mosquito-proof hut was designed and tested in semi-field and field settings against Shamba hut replicas, and actual Shamba huts. Also, semi-structured interviews were conducted, timed-participant observations, and focus-group discussions to assess experiences and behaviours of the farmers regarding mosquito-bites and the mosquito-proof huts.

Results: There were equal numbers of mosquitoes in Shamba huts and main houses [RR (95% CI) 27 (25.1–31.2), and RR (95% CI) 30 (27.5–33.4)], respectively (P > 0.05). Huts having >1 occupant had more mosquitoes than those with just one occupant, regardless of site [RR (95% CI) 1.57 (1.30–1.9), P < 0.05]. Open eaves [RR (95% CI) 1.15 (1.08–1.23), P < 0.05] and absence of window shutters [RR (95% CI) 2.10 (1.91–2.31), P < 0.05] increased catches of malaria vectors. All Anopheles mosquitoes caught were negative for Plasmodium. Common night-time outdoor activities in the fields included cooking, eating, fetching water or firewood, washing dishes, bathing, and storytelling, mostly between 6 and 11 p.m., when mosquitoes were also biting most. The prototype hut provided 100% protection in semi-field and field settings, while blood-fed mosquitoes were recaptured in Shamba huts, even when occupants used permethrin-impregnated bed nets.

Conclusion: Though equal numbers of mosquitoes were caught between main houses and normal Shamba huts, the higher proportions of blood-fed mosquitoes, reduced access to organized healthcare and reduced effectiveness of LLINs, may increase vulnerability of the itinerant farmers. The portable mosquito-proof hut offered sufficient protection against disease-transmitting mosquitoes. Such huts could be improved to expand protection for migratory farmers and possibly other disenfranchised communities.

No MeSH data available.