Agricultural Development and Vector-Borne Diseases (FAO - HABITAT - UNEP - WHO, 1996, 91 p.) Topic K: Rural settlements List of slides K.1 Overnight forest shelter, South East Asia K.2 Forest workers camp, South East Asia K.3 Forest family dwelling, Philippines K.4 Lahu village, Thailand K.5 Typical rice growing settlement, tropical lowlands of Bolivia K.6 Typical rice growing settlement, tropical lowlands of Bolivia K.7 Village scene, Myanmar K.8 Village scene, Myanmar K.9 Village ecology, rice growing area, Tamil Nadu, India K.10 Village scene, Egypt K.11 Displaced rural people in an urban slum, India K.12 Integrated rural settlement development, Nepal K.13 Use of impregnated mosquito nets in the Gambia

Agricultural Development and Vector-Borne Diseases (FAO - HABITAT - UNEP - WHO, 1996, 91 p.)

Topic K: Rural settlements

List of slides

K.1 Overnight forest shelter, South East Asia

K.2 Forest workers camp, South East Asia

K.3 Forest family dwelling, Philippines

K.4 Lahu village, Thailand

K.5 Typical rice growing settlement, tropical lowlands of Bolivia

K.6 Typical rice growing settlement, tropical lowlands of Bolivia

K.7 Village scene, Myanmar

K.8 Village scene, Myanmar

K.9 Village ecology, rice growing area, Tamil Nadu, India

K.10 Village scene, Egypt

K.11 Displaced rural people in an urban slum, India

K.12 Integrated rural settlement development, Nepal

K.13 Use of impregnated mosquito nets in the Gambia

Credit individual slides:

World Health Organization
K.1, K.2,
Food and Agriculture Organization of the United Nations
K.3, K.4, K.5, K.6, K.7, K.8, K.10, K.11, K12
Robert Bos, Geneva
K.9
Danish Bilharziasis Laboratory
K.13

K.1 Overnight forest shelter, South East Asia

Slide K.1 Overnight forest shelter, South East Asia

K.2 Forest workers camp, South East Asia

Slide K.2 Forest workers camp, South East Asia

The highly efficient malaria vectors in the forests of South East Asia, belonging to me Anopheles dirus complex, keep the transmission cycle going among forest workers, hunters and others who stay overnight in the jungle. Conventional chemical control methods (spraying house walls with residual insecticides) serve no purpose in the makeshift shelters as shown on slide K.1. Similar conditions prevail in the Amazon region of Brazil. In more permanent camps (slide K.2) chemical control can be used for endophilic vector species and the use of impregnated mosquito nets should be promoted for personal protection.

K.3 Forest family dwelling, Philippines

Slide K.3 Forest family dwelling, Philippines

The typical housing conditions of this subsistence farming family in Quezon Province, Philippines illustrates a seemingly Arcadian setting where nevertheless vector-borne disease risks, in this case malaria, are a reality.

K.4 Lahu village, Thailand

Slide K.4 Lahu village, Thailand

On-going deforestation around this village in northern Thailand will have reduced me immediate malaria risks. New developments may introduce new risks: rice cultivation combined with pig rearing will create conditions favourable to Japanese encephalitis, inadequate storage of drinking water (because of lack of drinking water or an unreliable supply) may lead to Aedes aegypti breeding and the risk of transmission of dengue and the establishment of commercial plantations may even bring back the malaria risks.

K.5 Typical rice growing settlement, tropical lowlands of Bolivia

Slide K.5 Typical rice growing settlement, tropical lowlands of Bolivia

K.6 Typical rice growing settlement, tropical lowlands of Bolivia

Slide K.6 Typical rice growing settlement, tropical lowlands of Bolivia

The living conditions of this rice growing family in Bolivia’s lowlands are affected by the various endemic diseases they are exposed to: malaria, yellow fever and some of the more exotic or emerging arboviral haemorrhagic fevers. This type of dwellings offers little or no opportunity for personal protection measures to become part of the structure.

K.7 Village scene, Myanmar

Slide K.7 Village scene, Myanmar

K.8 Village scene, Myanmar

Slide K.8 Village scene, Myanmar

This settlement in a rice producing area in Myanmar appears to have all the features of a place where vector-borne disease problems are not a mere hazard, but a real risk. Myanmar is one of the countries where rodent-borne diseases are a serious public health problem. Clearly, agricultural areas with storage of grains and other produce, have large rodent populations. Depending on the region, leptospirosis, plague or scrub typhus may be important public health problems.

K.9 Village ecology, rice growing area, Tamil Nadu, India

Slide K.9 Village ecology, rice growing area, Tamil Nadu, India

This slide shows several of the crucial elements of the ecology of a village in southern India (in this case: Vellikurichi, Tamil Nadu) in a rice growing area where Japanese encephalitis is endemic. There is a mix of human dwellings and cattle housing, both providing ample sources of blood meals for mosquitoes. On the fringes, vegetable gardens provide humid mosquito resting sites during the hottest period of the day, while the mosquitoes (of the Culex vishnui group) breed in the flooded rice fields beyond. Groups of trees serves as grooming places for birds: egrets and herons may transport the JE virus over great distances. The only element missing in this slide: pigs, which serve as the amplifying hosts for the virus.

K.10 Village scene, Egypt

Slide K.10 Village scene, Egypt

In this peri-urban scene from Egypt, the surfaced roads and concrete building represent me urbanization process, but both physical aspects (the drainage canal) and behavioural aspects (women doing the laundry in the canal) remind one of rural settings. It is in these unplanned peri-urban extension, where the urbanization process proceeds unplanned and institutional arrangements are hopelessly inadequate to deal with even the minimum of services required, that growing populations live under conditions that are very hazardous to their health, usually with little or no access to health services. Even the minimum requirements in urban planning are not respected, such as taking into consideration the gradient in connection with proper drainage. Where urban zoning plans exist, separating areas for residential purposes, for small industry and businesses, and green zones, there are no mechanisms to enforce these plans once construction is underway. Construction and design standards, which could help reduce health risks (as demonstrated in the case of rooftop drinking water tanks in relation to A. stephensi breeding in Bombay) are often not observed.

Where fresh water canals turn into organically polluted drains, malaria risks are replaced by those of filariasis; small water collection in and around the house in urban and peri-urban areas create ideal conditions for the transmission of dengue by Aedes mosquitoes

K.11 Displaced rural people in an urban slum, India

Slide K.11 Displaced rural people in an urban slum, India

When agriculture fails to support rural populations, there is an inevitable migration to urban centres. This community of landless poor lives in tents and shacks on the outskirts of Old Delhi, without access to safe drinking water or sanitary facilities. It can be questioned whether the health risks they left behind in their rural community are of a different magnitude from those they encounter in the new, urban setting.

K.12 Integrated rural settlement development, Nepal

Slide K.12 Integrated rural settlement development, Nepal

The development of integrated rural settlements, such as here in Nepal, aim to take the various aspects of rural life into consideration. This includes the provision of safe drinking water, adequate sanitation, the screening of houses where nuisance or vector mosquitoes are a problem, and the promotion of vegetable gardens to offer people a healthy and varied diet.

K.13 Use of impregnated mosquito nets in the Gambia

Slide K.13 Use of impregnated mosquito nets in the Gambia

With agricultural development, rural communities often improve their economic status to the extent where it becomes possible to purchase medicine, afford health services and buy personal protection devices against mosquito vectors, such as mosquito nets. The phenomenon observed in several irrigated rice schemes in West Africa of an increase in mosquito densities and a concomitant reduction in malaria transmission is, by some, explained by this economic progress.

Prices of mosquito nets vary, but in Senegal farmers in the St Louis area pay 6000 CFA francs for a two person net, which compares to an annual irrigation fee of 42 000 CFA francs for one hectare of land (1997 prices).

Mosquito nets can be used as a physical barrier, but they can also be impregnated with insecticide and help reduce vector populations. Social acceptability is a crucial factor for their success. In some cultures they are appreciated for the additional privacy they provide, but in hot climates they are experienced as uncomfortable.