7
Preventive Interventions

The acute emergency phase of a typical complex emergency lasts about four weeks,1 as relief organizations become better organized and able to meet the needs of the displaced or refugee population, major epidemic illnesses are controlled or prevented, nutritional programs begin to have an effect, the water supply approaches minimal requirements, and shelter is improved. As the situation becomes more stable, public health needs change. Malaria programs need to change too, from emphasizing curative services and reaction to real or potential epidemics to a more sustained control effort. This requires much more emphasis on community involvement in establishing interventions that are cost effective and sustainable.

Appropriate preventive services for malaria control must be defined based on the specifics of the local malaria situation but might include consideration of cost-effective and sustainable vector control strategies (e.g., insecticide-treated nets), prevention of malaria during pregnancy, environmental control, or even prophylaxis of high-risk groups.

1  

As described in Chapter 2, there is much variation in the terms used to describe the stages of a complex emergency. Rather than trying to define a specific time period when preventive services are most required, it is more pragmatic to focus on the period of time when the most pressing critical needs are being met in a routine manner, most likely as a result of humanitarian efforts being operationally functional.



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Malaria Control During Mass Population Movements and Natural Disasters 7 Preventive Interventions The acute emergency phase of a typical complex emergency lasts about four weeks,1 as relief organizations become better organized and able to meet the needs of the displaced or refugee population, major epidemic illnesses are controlled or prevented, nutritional programs begin to have an effect, the water supply approaches minimal requirements, and shelter is improved. As the situation becomes more stable, public health needs change. Malaria programs need to change too, from emphasizing curative services and reaction to real or potential epidemics to a more sustained control effort. This requires much more emphasis on community involvement in establishing interventions that are cost effective and sustainable. Appropriate preventive services for malaria control must be defined based on the specifics of the local malaria situation but might include consideration of cost-effective and sustainable vector control strategies (e.g., insecticide-treated nets), prevention of malaria during pregnancy, environmental control, or even prophylaxis of high-risk groups. 1   As described in Chapter 2, there is much variation in the terms used to describe the stages of a complex emergency. Rather than trying to define a specific time period when preventive services are most required, it is more pragmatic to focus on the period of time when the most pressing critical needs are being met in a routine manner, most likely as a result of humanitarian efforts being operationally functional.

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Malaria Control During Mass Population Movements and Natural Disasters PREVENTIVE USE OF ANTIMALARIAL DRUGS Generally, prophylaxis of large populations is not realistic. Attempts to implement malaria prophylaxis strategies on a large scale have consistently faltered. Noncompliance rates are high, overall cost is high, and long-term sustainability is low. For these reasons mass chemoprophylaxis for malaria control in large populations is not recommended. There are other situations, however, where limited use of malaria prophylaxis is worth considering. Discrete populations, especially groups with little or no immunity to malaria, for which daily or weekly contact with a health care provider is possible may benefit from prophylaxis. Although relatively few evaluations have been done, in either stable or displaced populations, prophylaxis strategies for defined groups such as pregnant women, orphans, unaccompanied minors, or laborers who are housed together for prolonged periods of time could be both effective and manageable. Preventive Use of Antimalarial Drugs During Pregnancy Pregnancy is a situation where malaria prevention should be actively encouraged, as pregnant women are at greater risk of malaria infection than nonpregnant women. However, the practical realities mentioned above make such preventive intervention difficult. While chemoprophylaxis during pregnancy has traditionally been the intervention of choice, a relative lack of drugs that are both suitable for prophylaxis and safe during pregnancy as well as poor compliance and widespread drug resistance normally preclude the use of chemoprophylaxis in most areas (Schultz et al., 1994; Steketee, Wirima, and Slutsker, et al., 1996; Robb, 1999). Nonetheless, in areas without chloroquine resistance, weekly prophylaxis with the drug offers a safe and effective method for prevention of placental malaria infection (providing compliance can be maintained at high levels). Mefloquine has been used prophylactically to prevent malaria during pregnancy and has been shown to be both safe and effective (Nosten et al., 1994b), although more recently concerns have been raised about a possible association between mefloquine use during pregnancy and an increased risk of stillbirth (Nosten et al., 1999b). In areas where chloroquine or mefloquine resistance is common, where mefloquine is not financially viable, or where prophylaxis schemes are unsustainable (which accounts for most malarious areas of the world), alternative strategies to prophylaxis are needed. Often, in these areas and/

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Malaria Control During Mass Population Movements and Natural Disasters or populations the only routinely available strategy, often by default, is one based on prompt diagnosis and effective case management. In some places, because of multidrug resistance and a lack of effective drugs that can be used prophylactically, case management is the only viable strategy, although it is insufficient to eliminate the adverse impact of malaria in pregnancy (Nosten et al., 1991; McGready et al., 1998, 2000). Among populations in sub-Saharan Africa with a high level of acquired immunity, many malaria infections during pregnancy are asymptomatic (Phillips-Howard, 1999). Additionally, as mentioned previously, most attempts to rely on weekly chemoprophylaxis during pregnancy have met with failure, primarily due to resistance to the drugs most commonly used for prophylaxis (chloroquine) and poor compliance. Therefore, at least in areas of intense stable malaria transmission, neither case management nor weekly chemoprophylaxis can be relied on to adequately protect women and their fetuses from malaria. In such situations, intermittent protective treatment (IPT) with sulfadoxine/pyrimethamine (SP) during the second and third trimesters of pregnancy has been shown to be both an effective and a cost-effective method of preventing malaria-associated maternal anemia and low birth weight (Schultz et al., 1994, 1995; Verhoeff et al., 1997; Parise et al., 1998; Shulman et al., 1999). IPT differs from chemoprophylaxis in that chemoprophylaxis refers to frequent use of a drug (either daily or weekly, depending on the nature of the drug) in order to prevent illness. IPT refers to intermittent treatment doses of a drug given presumptively (i.e., not based on presence of illness or demonstrated malaria infection) on a less-frequent basis (such as monthly or even less often). The purpose is to periodically clear existing infections and, depending on the nature of the drug, provide a period of lingering protection from illness. The latter effect is achieved when using drugs for IPT, such as SP, that have long half-lives (essentially, the period of time needed for the blood concentration to be reduced by half). After a drug is given, blood drug levels peak and then diminish over time as the drug is eliminated from the body: as long as the drug blood level remains above the minimum required to inhibit parasite growth, the patient should be protected from malarial illness. Because of the opportunity to link this strategy with antenatal care visits, this approach offers an implementable and sustainable intervention. Various limitations, however, argue against the use of such a strategy in many areas. Resistance to SP is prevalent in South America and Asia and is becoming a serious concern in sub-Saharan Africa. Other antimalarial drugs (mefloquine monotherapy, combination therapy including an

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Malaria Control During Mass Population Movements and Natural Disasters artemisinin compound, or other drugs) have not been studied as part of an IPT strategy but may be an option in areas where they are effective for routine treatment of uncomplicated malaria. Among nonimmune populations and/or in areas with low malaria transmission rates, the relative infrequency of infection, the high likelihood that such an infection would be symptomatic, and the real risk that a mild infection could rapidly become severe might decrease the usefulness or effectiveness of an IPT approach. There is a small amount of data that suggest P. vivax infections also place pregnant women at risk of anemia and their babies at risk of low birth weight (Nosten et al., 1999a). HIV Infection and Malaria During Pregnancy As mentioned previously, later pregnancies (third or more) appear to be at as great a risk of producing low-birthweight babies as first and second pregnancies among women who are HIV (human immunodeficiency virus) seropositive (Steketee et al., 1996b). HIV infection also appears to reduce the protective effect of intermittent antimalarial therapy. Populations with relatively high HIV seroprevalence (>15 percent) have been shown to achieve a high degree of protection against malaria when IPT is given on a monthly basis (Parise et al., 1998). Prophylaxis of Other High-Risk Populations Anemic children (especially those who received blood transfusions because of severe anemia), severely malnourished individuals receiving therapeutic feeding, and nonimmune populations newly exposed to malaria transmission would likely benefit from preventive use of antimalarial drugs. This could be accomplished either through routine chemoprophylaxis or by using a system of regular presumptive treatment along the lines of IPT during pregnancy. For example, one study in Africa of presumptive treatment for malaria at the time of routine infant vaccinations reduced the rates of both clinical malaria and severe anemia compared to a placebo treatment (Schellenberg et al., 2001). Prophylaxis or presumptive therapy might also be advisable for severely malnourished individuals. Therapeutic feeding of starved individuals has been shown to reactivate preexisting, but quiescent, malaria infections, with potentially severe consequences (Murray et al., 1976, 1978). A short period of prophylaxis or presumptive treatment during nutritional rehabilitation might prevent these recrudescent

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Malaria Control During Mass Population Movements and Natural Disasters infections. Ideally, prevention should include more than a single approach. For example, other measures, such as insecticide-treated bed nets, would be appropriate preventive strategies in many situations. Other Prevention Issues A number of intervention studies have investigated the contribution of specific nutrients to exacerbation or prevention of malaria. Parenteral iron supplementation during pregnancy has been shown to increase the risk of malaria infection among primigravidae, whereas oral supplementation of multigravidae did not (Oppenheimer et al., 1986b; Menendez et al., 1994). A clinical trial that provided iron supplementation (with and without malaria prophylaxis) to a population of children less than 1 year old who were exposed to intense perennial malaria transmission was effective at preventing severe anemia and clinical malaria (Menendez et al., 1997). In another study, zinc supplementation reduced clinic attendance due to malaria and dramatically reduced high-density malaria infections (Shankar et al., 2000). Other nutrients that may be important in reducing malaria morbidity or mortality include vitamins A and C, riboflavin, betacarotene, and various antioxidants (Shankar, 2000). Provision of a program of nutritional supplementation to a displaced population, while difficult, is not impossible. In a study of Burundian refugees in Tanzania, supplementation of moderately anemic children with varying combinations of iron, folic acid, vitamins A and C, and monthly presumptive malaria treatment was achieved using a cadre of home health visitors, resulting in substantial hematological recovery and improvement in iron stores (Tomashek et al., 2001). INSECTICIDE-TREATED BED NETS Insecticide-treated nets (ITNs) impregnated with inexpensive and long-lasting pyrethroids have been shown to reduce human-vector contact, inoculation of humans with sporozoites, clinical episodes of fever, high-density parasitemia, malaria-attributed mortality, and overall mortality (Bermejo and Veeken, 1992; Choi et al., 1995; D’Alessandro et al., 1995; Lengeler, 1998). Reviews of published reports suggest that the overall protective efficacy of ITNs for mortality in children less than 5 years old was about 18 percent and against mild malaria episodes 39 to 48 percent (Lengeler, 1998). ITN usage was also associated with higher-packed cell

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Malaria Control During Mass Population Movements and Natural Disasters volumes in children. There was also a trend for greater protective efficacy in areas with low-to-medium transmission compared to high transmission. ITNs have been used for malaria control in displaced populations with success in some settings. In Nepal a combination of ITNs and active case detection and treatment reduced the incidence of malaria from approximately 22 cases per 10,000 persons per day to 0.2 cases (Martin et al., 1994). In Thailand, ITNs reduced P. falciparum infections and episodes of clinical malaria among displaced school-aged children and reduced the incidence of malaria-associated anemia in displaced pregnant women (Dolan et al., 1993; Luxemberger et al., 1994). ITNs were also shown to produce a modest reduction in cumulative infection rates of migrant workers in eastern Thailand (Kamol-Ratanakul and Prasittisuk, 1992). ITN programs for Afghan refugees in Pakistan have also met with considerable success (Rowland et al., 1996; Rowland, 1999). Bed nets are easily installed over beds or floor mats, can be readily moved, protect one or more persons (depending on users’ ages and the sizes of the nets available), provide some warmth and enhanced privacy at night, are generally affordable, and can last for years with proper care. The process of impregnating and hanging the nets is not complicated. Studies have clearly demonstrated that motivated community members can be taught to use bed nets properly and to do the impregnation, drying, hanging, and maintenance with only modest assistance from local governmental health staff. Depending on seasonality of malaria transmission and the frequency of washing, bed nets may require retreatment as often as twice per year or more frequently (World Health Organization, 1997c). Low retreatment rates of nets have frequently been identified as an important obstacle to implementing an effective ITN program (Cham et al., 1997; Curtis and Mnzava, 2000). “Permanently” treated nets (also known as wash-durable or long-lasting insecticide-treated nets) have been developed and are being evaluated under field conditions (Guillet et al., 2001). While use of these nets may increase initial program costs, the elimination of the need for retreatment may make them more effective over the life of the net. If ITNs are widely distributed and used in a community, infective vector density should be reduced, resulting in decreased vector-human contact, lowered malaria transmission, and decreased morbidity and mortality. These effects can occur even when ITNs are torn and benefit extends to nonnet users in the same house (Lindsay et al., 1991). At higher levels of coverage, protection extends even to non-users of ITNs living in nearby

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Malaria Control During Mass Population Movements and Natural Disasters houses (Howard et al., 2000). Recent data from an area of intense transmission suggest that coverage needs to be at least 50 to 60 percent in order to achieve these community benefits (W. Hawley, Centers for Disease Control and Prevention, personal communication, 2002). In fact, recent studies suggest that the effectiveness of insecticide-treated nets is due primarily to the action of the insecticide and the extent of coverage, while the physical barrier effect is of minimal importance (Hawley et al., in press). For this reason, if ITNs are to be used, rapid implementation aimed at achieving high coverage should be stressed to obtain maximal benefits from the program. ITN programs that achieve low coverage rates or fail to treat (or retreat) nets appropriately with insecticide are likely to accomplish little more than the wasting of valuable resources (Hawley et al., in press). Insecticide-Treated Curtains Insecticide-treated curtains (ITCs) have been shown to reduce human-vector contact and to reduce morbidity and mortality due to malaria (Cuzin-Ouattara et al., 1999; Habluetzel et al., 1997, 1999). In certain circumstances ITCs could play an important role, especially where refugee housing consists of small houses with one room, one door, and one or no windows. In such cases, ITNs would hinder movement around and use of the room, whereas curtains would be out of the way yet serve essentially the same purpose. Economic Feasibility The economic feasibility of using ITNs as an intervention has been examined in a number of settings. The cost to distribute ITNs to an entire camp population of displaced Karen in Thailand was examined (Luxemberger et al., 1994). The number of malaria treatments for P. falciparum that would be avoided by ITN use was estimated to be 310 to 1,748. (The cost to treat this number of cases of malaria would be $744 to $4,195.) Although this may have been a cost-effective intervention over the course of a number of years, the life span of the net, generally only about a year in that environment, was judged to be the most important obstacle. In terms of the cost to the community itself, an investment in a successful ITN intervention in both Malawi and Cameroon would be outweighed by the savings associated with decreased morbidity and decreased

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Malaria Control During Mass Population Movements and Natural Disasters mortality due to caring for sick individuals (Brinkmann and Brinkmann, 1995). In the Gambia the estimated cost of death averted by a successful ITN intervention was $600, a cost thought to compare favorably with other interventions, such as measles vaccination and oral rehydration solutions (D’Alessandro et al., 1995). ITN use also compared favorably to other vector control methods. In the Solomon Islands the per-capita cost of an ITN program was $1.97 compared with a per-capita program cost of $4.37 for indoor residual spraying with dichlorodiphenyltrichloroethane (DDT); efficacy data were not available (Kere and Kere, 1992). In South Africa, ITN use, while more effective in terms of reducing malaria cases, was found to be more expensive than residual house spraying (Goodman et al., 2001). However, the price per net used in this analysis was substantially higher than current market prices, and, assuming more typical net prices, the cost of using ITNs would have been lower than using residual spraying. Furthermore, by including costs saved through decreased treatment of malaria cases, ITNs would have resulted in a net savings. Using established guidelines, both ITN programs and residual spray programs would be considered cost effective and attractive health investments (cost per disability-adjusted life year averted was less than $150; Goodman et al., 1999). The cost of an ITN program will depend on bed net size, model, type, quality of material, and country (MacCormack et al., 1989). Prices for both nets and insecticides vary by country and product. Wholesale net prices are currently under $4 and in some areas even less (Goodman et al., 2001). Similarly, costs for insecticides vary widely but are generally low. OTHER PERSONAL PROTECTION MEASURES People can help protect themselves from acquiring malaria (or other vectorborne diseases) by using simple measures that decrease the likelihood of coming into contact with vectors. Through a basic understanding of the vector’s habits, especially the time of day it most likely feeds, people can modify their behavior and/or activity patterns to decrease their exposure. For example, many malaria vectors are particularly active from late dusk to dawn; if people use repellents on their exposed skin and clothes, wear long pants, long-sleeved shirts, and a hat, and stay indoors behind screened entries, their risk of exposure to disease-carrying vectors will be greatly reduced. Obviously, in many situations associated with rapid or unplanned migration, these measures are unlikely, impractical, or impossible and, even

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Malaria Control During Mass Population Movements and Natural Disasters under optimal conditions, would be difficult to implement and sustain. These measures may be beneficial on an individual level, but on a population basis they would probably have, at best, only a limited effect on malaria morbidity. Repellents Permethrin, a synthetic pyrethroid, can be used to impregnate clothing to repel insects. While it is very effective in preventing insects from biting through impregnated clothing, it offers minimal protection to exposed skin. Permethrin-impregnated clothing can be washed a number of times and still retain sufficient material to repel insects. This approach has been used effectively among some Afghan refugees in Pakistan by impregnating blankets or chaddars, a traditional wrap worn by Afghan women and used by both men and women as a sheet at night (Rowland et al., 1999; Rowland, 2001). The cost of treating chaddars was estimated to be $0.17 per person. Since chaddars were already used by these communities, this strategy avoided the additional cost of net purchase (Rowland et al., 1999). DEET (N,N-diethyl-m-toluamide) is a repellent used on exposed skin. It is effective for a number of hours, but perspiration reduces its effectiveness. Soap containing a combination of DEET and permethrin has been evaluated in a number of settings, none involving complex emergencies (Kroeger et al., 1997). Although protective efficacy was generally high when soap was used, motivation for continued use over time was low, and factors such as activity level and sweating adversely affected its impact. Since distribution of soap has other health benefits, including reduction of diarrheal disease, and is a frequent inclusion in refugee provisions, even a small added benefit might be worth the incremental expense of distributing repellent soaps (Peterson et al., 1998). However, soap distribution in general remains inadequate in most situations of displacement. In Peru and Ecuador in 1997, soap distribution was estimated to cost $4.60 per person per year (Kroeger et al., 1997). VECTOR CONTROL USING INSECTICIDES Role of Vector Control in Emergencies The role of insecticidal vector control in an emergency setting will depend, to a great extent, on the local epidemiology of malaria, the feeding

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Malaria Control During Mass Population Movements and Natural Disasters and resting behavior of the major mosquito vectors, and the capacity of relief organizations to mount and sustain vector control activities. A knowledgeable entomologist should be consulted regarding the appropriateness of vector control using insecticides, which insecticide(s) to use for a given intervention and area, and proper use and application of insecticides. The two principal methods of using insecticides for vector control are larvaciding and adulticiding. Larvaciding is the control of mosquito breeding with insecticides. This form of control is most effective when only a few discrete breeding sites are responsible for the majority of the transmission but can become impossible if breeding sites are poorly defined or numerous. For example, An. gambiae (an important malaria vector in most areas of sub-Saharan Africa) frequently breed in almost any groundwater, from hoofprints to flooded rice fields. The cost is proportional to the area of water to be treated, so the method may not be economical except where there are high-density larval populations. Adulticiding (using insecticides to kill adult mosquitoes) is technically less demanding, requiring more training but less skill. It is effective against vectors that rest on the walls of houses either before or after taking blood. The cost is proportional to the number of houses treated. Historically, in most circumstances adulticiding proved to be more useful than larvaciding and should be used preferentially unless it can be proven that larvicidal application is practical and effective, such as might occur when the vector bites outside houses and breeding sites are few and well defined. Adulticiding can be accomplished with residual or space spraying. Residual spraying involves the application of insecticides to the inside walls of a building, tent, or other shelter. It is most effective against mosquito vectors that both bite and rest indoors. Mosquitoes that immediately leave the structure after feeding are obviously not exposed to the insecticide. Space spraying is aimed primarily at killing flying mosquitoes and is generally a far less efficient and cost-effective method of mosquito control. It has been used in epidemic situations in order to get a rapid decrease in adult mosquito populations and as a highly visible intervention. ITNS OR RESIDUAL SPRAYING IN REFUGEE SETTINGS? Studies have shown that in most settings ITNs and residual spraying programs have approximately the same level of efficacy and cost effectiveness for preventing malaria (Goodman et al., 1999; Curtis and Mnzava, 2000). Comparisons between programs (or studies) using either ITNs or

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Malaria Control During Mass Population Movements and Natural Disasters residual spraying do not give a clear answer in terms of cost. In some settings nets were less expensive; in others spray programs were less expensive. Therefore, the decision to opt for one over the other for malaria control for a displaced population revolves around local logistical constraints. Provided that either could be used effectively against locally prevalent malaria vectors, they each have their advantages and disadvantages. It is important to remember that net distribution will not ensure that the nets will be kept, will be used properly, or that the most vulnerable members of households will benefit from their use. Among displaced populations, ITNs can be viewed as a valuable commodity to be traded for other desired goods, such as food items, or sold for cash. In camps in western Tanzania, almost 50 percent of nets distributed to Burundian refugees were missing less than 3 months later; in a second camp only about 15 percent of nets remained 1.5 years after original distribution (International Rescue Committee, unpublished data, 1997). This is a problem that may diminish over time as communities become more stable and the benefits of net use are more widely appreciated, but trading or selling nets rather than using them can clearly compromise the public health impact of an ITN program (Curtis and Mnzava, 2000; Rowland, 2001). ITN use presumes that a displaced population has shelter that can accommodate a net. While nets can be made to fit into very small shelters, those commercially available in large quantities are typically too large to fit in many shelters commonly found in refugee camps, especially early in an emergency phase. Successful ITN use is highly dependent on community acceptance and participation. Not only does the community need to use the nets, its residents must adhere to reimpregnation schedules for optimal effect. Among some stable populations, nets are often used exclusively by the male head of household, leaving the more vulnerable children unprotected (Makemba et al., 1995; Van Bortel et al., 1996). In comparison, residual spraying requires only passive community participation. Spray teams can rapidly move through a settlement and achieve complete coverage in a short period of time. Residual spraying does not require any specific behavioral change on the part of household members (Rowland, 1999). However, some shelter types would not be amenable to residual spraying; insecticides do not stick well to plastic sheeting, although residual spraying of cotton and canvas tents was effective for refugee populations in Pakistan (Hewitt et al., 1995). Studies are under way to develop

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Malaria Control During Mass Population Movements and Natural Disasters methods to impregnate shelter materials, such as plastic and canvas sheeting, and blankets (Rowland, 2001; World Health Organization, 2001a). Even when ITNs are preferable, it may take time and stability to successfully implement an ITN program. Adequate time and effort should be placed on designing the most appropriate community education program in order to teach the proper use of nets and to highlight vulnerable populations who most need this protection. In such situations a residual spray campaign could be used early in a complex emergency for rapid coverage, and then, as the situation stabilizes, there would be a transition to an ITN strategy. In the Tanzanian camps mentioned previously, the nongovernmental organization on the scene stopped campwide ITN distribution in favor of a twice-yearly residual spraying campaign, while community health workers attempted to improve ITN use through health education. ENVIRONMENTAL AND BIOLOGICAL VECTOR CONTROL When vector breeding sites are few in number and easily identified, environmental or biological control may be a viable option. Environmental management strategies include such activities as draining or filling in pools of water, modifying the boundaries of rivers or other water drainage systems, and applying materials to open water, such as oil or styrofoam beads, to disrupt larval development. Biological control strategies, including use of bacteria (such as Bacillus thuringiensis subsp. israelensis, or Bti) or larvivorous fish, have also been used with other control measures and with variable levels of success (Karch et al., 1992; Romi et al., 1993, World Health Organization, 1999a; Kaneko et al., 2000). Data that prove the effectiveness of some commonly recommended environmental control measures against malaria, such as cutting or clearing grass from around dwellings, are lacking. If the situation permits, the location of settlement areas for displaced populations should be chosen or reviewed with attention to the potential risk for vectorborne disease. Similarly, planning for developmental projects should include consideration of the impact on vector breeding sites (World Health Organization, 1998). RECOMMENDATIONS Review supply management procedures and ensure a reliable source of antimalarial drugs, nets or curtains (if used), and insecticides.

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Malaria Control During Mass Population Movements and Natural Disasters Ensure prompt, safe, and effective case management of malaria for all pregnant women. Establish intermittent protective treatment for pregnant women in areas with high malaria transmission. Seek guidance from an experienced medical entomologist to identify and implement appropriate cost-effective vector control strategies. Consider initial use of a residual spray program, even if insecticide-treated nets are ultimately used, to achieve rapid protection and to afford sufficient time to develop and implement a sustainable net program. Consider ways to integrate malaria prevention for children and pregnant women with nutritional support activities and/or antenatal care. Design an appropriate community education program to teach proper use of nets and to highlight vulnerable populations who most need this protection (if a net program is deemed the best approach to use). If insecticide-treated nets are to be used, the rapid attainment of high coverage (>50 percent of households) should be stressed. Reconsider using nets if it is unlikely that high coverage rates can be attained (in such cases, residual spraying may be a more cost-effective approach). Malaria Prevention Interventions: Key Points Malaria control must rapidly evolve from simple provision of curative services to development of a more sustainable control program that includes preventive interventions. Preventive services should be tailored to the specific situation and may include a variety of approaches, such as use of insecticide-treated materials or prevention of malaria during pregnancy using intermittent protective treatment. Vector control strategies should be formulated on information regarding the local epidemiology of malaria, the feeding and resting behavior of the principal mosquito vectors, and the ability of relief organizations to mount and sustain vector control activities. There is an increasing body of evidence pointing to interactions between malaria, anemia, and malnutrition. As evidence accumulates, it may become important to integrate malaria prevention activities with nutritional support activities.